OUR WORK

 

­­­­Owl-inspired experimental study on flow-induced vibration suppression with aerospace applications

 

By Abdul Raffae

 

Portrait of Abdul Raffae (left) at work in Fluid-Structure Interactions Research Laboratory at UMass-Dartmouth

 

 

In today’s industries, turbulent fluctuation causes flow induced noise that has been a major contribution to noise generation of modern structures. Many aeronautical and turbine application are rapidly developing to ensure noise reduction to better understand and control the acoustic of noise and structural vibration. In my research Fluid-Structure Interactions (FSI) is used to study the deformation or oscillation (Flow-Induced Vibration) of the structure that will go through fatigue failure in long term. In this proposed work, an owl wings will be going through detailed experimental campaign to understand the source of this turbulent and find strategies to suppress the FIV in such flexible structures. Three dominant noise-attenuation factors have been identified in owl wings that includes comb-like structure, trailing-edge feathers, and the velvet-like have been identified.

 

View of the Fluid-Structure Interactions Research Laboratory at UMass-Dartmouth where Abdul conducted his research

 

 

In Fall 2021, a flexible circular cylinder with trailing-edge serration was 3D modeled using SOLIDWORKS software cased from silicone material. This was done thanks to using the re-circulating water tunnel at Professor Banafsheh Seyedaghazadeh‘s Fluid-Structure Interactions Research Laboratory at UMass-Dartmouth. Subsequently, the effects of serrations geometry, length and aspect ratio were studied using FIV response. Since then I have been working closely with the lab to find solutions to the problem. I am planning to publish the result of this research in a peer-reviewed journal. While I cannot provide more details here, I can tell you that the impact of this research is essentially to determine the noise vibration in aeronautical and micro aerial applications. I want to thank Professor Seyedaghazadeh and other colleagues at the lab for their support. The Summer OUR fund provided an opportunity to be on campus and dedicate more time to lab work. I am grateful to the OUR for this unique opportunity.

Congressman Barney Frank and his Contributions to the LGBT Community

 

By Carmen Zhao

 

I was first introduced to the OUR summer research project by my supervisor Chan Du. In 2011 Massachusetts Congressman Barney Frank donated his archives collection that documented his U.S. congressional career from 1980-2012. They are currently located in the library’s Archives and Special Collections at UMass Dartmouth and are sorted in many boxes. During the summer, I was able to spend many hours in this room sorting through Frank’s archives to help with my research. The collection is categorized into 6 series, legislative files, district files, election and legislative records, correspondence, press and public relations, and artifacts and awards. This collection is currently in the process of being digitized. During the end of summer I was assigned a supervisor in the library, Ms. Judy Farrar. With Farrar’s help I learned how to navigate the archives and special collections. At the same time, I helped with scanning old photographs associated with Barney Frank, while investigating photographic materials for my own research. After I digitized the photos I had to try to identify the dates when these photos were shot; I was also charged with the task of identifying the photographers who took them. Subsequently, I helped write labels that would go along with these photos. When working on these descriptions it was important for me to recognize some of the people’s faces in the photos who had posed with Barney. Using Barney’s archives I was able to look through the boxes and go through newspapers and articles to try to identify and match any of the unfamiliar faces from the photographs to the names that appeared in newspaper clippings.

Portrait of Carmen Zhao

 

Barney Frank was a popular congressman, but to keep his political career “safe” he kept a secret about his identity for many years. When I first started this research project I knew little about the many sides of Barney Frank’s character. I first started by watching his documentary ‘Let’s Get Frank.’ Then I read about him in books, one an autobiography and another by Stuart E. Weisberg. These materials were helpful to me as they allowed me to get a more complete picture of Frank’s life and career. While looking through the photo albums I got to see digital images from Frank’s campaigns and public appearances. While conducting the photo research I was able to put some faces to the names that were mentioned in the books. I wrote my research paper about Barney Frank’s political career as a gay man. Frank’s biggest struggle seemed to be separating his personal life with his public life. I found how keeping his sexuality a secret effected some of the choices he made and how he was able to gain people’s trust back once he came out. I studied if he had come out earlier, he could’ve effected the outcome of his 1980 congressional run or the Democratic Primary when fighting conservative candidate, Arthur Clark. Barney defeated him in the general election in a close race. The same thing happened when Frank took on former Congresswomen Margaret Heckler in 1982, the disclosure of his sexual preferences may have lost him in these elections. It was interesting to see how these career choices and the timing of them effected the outcomes of Frank’s career. Delving into the archives was helpful because I was able to find press clippings from the years mentioned in the book related to his political fallouts that supported my paper.

 

Snapshot from Carmen’s contribution to the collection. More can be found HERE

 

UMass Dartmouth Archives and Special Collections where Carmen

conducted her research through an OUR Summer Award. 

 

I found reactions from different newsletters like the Attleboro Sun, Taunton Daily Gazette, Dover-Sherborn Suburban Press, Sun Chronicle, and Arizona Republic which published  stories when Barney voluntarily came out. These pieces expressed a variety of thoughts and opinions on the situation.  It was very informative to know that Frank was not alone in this struggle. There were many people who were closeted politicians as Barney mentions some of his gay colleagues in his writings. However, the important point to highlight here is that while still silent about his sexual orientation, Barney was an advocate for LGBT. In the archives legislative files are divided into sessions of Congress and special issues. There I found his dealings with LGBT issues and I was able to find more information on these issues that occupied a good portion of Frank’s career. I plan to expand my research paper based on my work at the archives and hopefully publish it in the near future. The extended paper will focus on Frank’s early struggles that soon forced him to make the decision to come out despite the possible negative effect on his career. For this research opportunity, I am grateful to the OUR as well as to my advisor Associate Dean Chan Du and supervisor Judith Farrar.

 

 

Determining the Therapeutic Effects of VitB on Type II Diabetic Bone

By Christian Ray

 

 

Introduction

It has been hypothesized that Type 2 Diabetes Mellitus (T2DM)may be a direct cause of osteoporosis due to a decrease in bone tissue quality.^1,3 For example, one study found that T2DM was responsible for a 2-3 times increase of hip fracture risk.¹ While the presence of T2DM was initially thought to be a favorable effect on bone strength since it could increase the mineral density of the tissue, this idea was later reassessed through more detailed and rigorous analysis procedures; furthermore, it has been found that while the amount of bone mass and magnitude of mineral density are relatable to bone strength, the density of diabetic bone does not promote bone toughness and in fact decreases it.^3,8 These procedures, such as micro indentation and computer-generated tomography, revealed that the increase in mineral density had numerous detrimental effects on bone strength including bone remodeling inhibition, increased bone resorption, and overall poorer tissue quality.³

Portrait of Christian Ray

 

To be more specific, bone tissue quality can be deteriorated by non-enzymatic glycation (NEG), a naturally-occurring process resulting in the increase of advanced glycation end-products (AGEs).⁷ The AGEs intra- and inter-fibrillar crosslinks that form throughout the collagen fiber network, causing the matrix to have stiffer properties and thus become more susceptible to breakage; this is a significant factor since over 90% of bone tissue is comprised of collagen fibers which are directly responsible for the elasticity, strength and overall toughness of bone.^7,8,9 From a chemistry viewpoint, the NEG process is the reaction of a reducing sugar (such as ribose) and an amino group (such as lysine and hydroxylysine) from the collagen. In addition, AGE accumulation has also been known to inhibit bone resorption thus leading to a decrease in bone turnover, an important biological process for maintaining bone tissue quality.⁶ Therefore, it is possible that AGEs affect the bone’s mechanical strength by deteriorating tissue quality through the bone resorption process.⁶ Overall, the accumulation of AGEs interferes with the bone structure by degrading the tissue quality and changing its mechanical and chemical properties; furthermore, this process can be further progressed due to aging and diseases such as T2DM.^7-9

 

For this project, together with my peers and mentor Professor Lamya Karim at the Bone Biomechanics Lab at UMass Dartmouth, we aimed to test a drug that can reverse or reduce the harmful effects of AGEs in bone. We decided to utilize the properties of Vitamin B6 (also known as pyridoxamine hydrochloride) due to its ability to counteract AGE formation in bone tissue.^11,12 It is also an ideal treatment due to its natural presence in foods and food supplements, meaning that it is less likely to have harmful side effects unlike previously tested AGE inhibitors. Because of the lack of in-depth mechanical research of vitamin B6 as a treatment for bone deterioration, it is necessary to perform controlled studies on bone treated with varying doses of vitamin B6 in vitro. This will provide useful information to improve treatment for T2D patients.

 

Overall, there is still insufficient research and information regarding the processes and effects of AGEs on bone. The goal of this study is to determine the extent of VitB6 effectiveness as an AGE inhibitor as well as to find any unexpected effects due to the compound.

 

 

Methods

Specimen Collection

All bone samples were collected from the left tibia of 4 female human donors; 3 of these donors had no records of leg-related injuries or bone-affecting diseases and pharmaceuticals, while the fourth donor had Type 2 diabetes. The bone specimens were always shipped frozen with ice packs and insulating boxes and then stored at –20^oC for preservation purposes. Once received, the tibias were each cut into 6 sections using a Craftsman 10” Band Saw where 15% of the total bone was removed from each end and the remaining middle part was divided into four sections. The proximal and distal ends were wrapped in saline-soaked gauze and stored away at -20^oC for other projects. The medial halves of the lateral sections were then cut off using an IsoMet 1000 Precision Saw with a medium-coarse grit diamond blade; the medial halves were then stored in saline-filled zip lock bags and stored at –20^oC for other projects. Using the same saw, each of the lateral halves were then vertically divided into 8-10 cortical beams. Once completed, a South Bay Technology Model 900 Polisher was used to remove the trabecular bone and soft tissue from the beams and to narrow the dimensions down to 2mm x 2mm x 30mm. To maintain awareness of their orientation, the periosteal surface was marked with black ink, and the proximal and distal ends were marked with red and green ink, respectively. The finished beams were then stored in saline-filled microtubes and frozen at –20^oC in cryoboxes.

 

Microcomputed Tomography Imaging

After the beams were done being cut and polished to the correct dimensions, they were then shipped out to Beth Israel Deaconess Medical Center to be imaged via high-resolution Micro-CT to obtain measures of tissue mineral density, cortical porosity, and overall beam geometry.¹⁰ In order to preserve the tissue quality of the samples, the samples were stored in saline in microtubes and cryoboxes and then stored in Styrofoam-insulated boxes with dry-ice.

 

In Vitro Biochemical Incubations

In order to incubate 60 beams in total, the required chemicals for the various solutions were calculated beforehand, as shown in Table 1. Overall, the 60 beams were randomly divided into 5 incubation groups labeled as Control, Ribose, 50mM, 75mM, and 100mM. The Control solution consisted of all the main chemicals aside from the ribose and vitamin B, while the Ribose contained all of the main chemicals aside from vitamin B. The rest of the solutions (which also consisted of the same concentration of ribose) were labeled based on their concentration of vitamin B. The individual amounts of the chemicals in reference to each solution are shown in Table 2.

In order to be more time efficient and ensure consistency of the chemical compositions between the solutions, we mixed all of the ingredients except the ribose and Vitamin B in a 5-gallon glass container with a long, polymer-based, stirring rod. After pouring out enough of this solution into the Control beaker, we added the total amount of ribose into the container and mixed until completely dissolved; once complete, we poured it into the four remaining types of beakers. Then, various amounts of vitamin B were added and dissolved into its respective beakers.

Once the chemicals were all added into the various beakers, the pH of them were individually adjusted using 0.5N NaOH or 0.5N HCl in order to bring the pH within the range of 7.2-7.6; later on, we chose to start using tablets of NaOH due to the rapidly increasing volume from using the diluted version. After the pH was adjusted, the samples were placed in labeled cassettes and randomly put into the five solutions. The beakers were then covered with parafilm and incubated at 37^oC for 14 days, with their pH levels measured and adjusted daily. On the 14^th day, the samples were removed from the beakers, rinsed off with saline, and stored in their respective microtubes with saline and frozen at -20^oC.

Discussion

While most of the project went smoothly throughout the summer, there were some unexpected factors that hindered the projects time efficiency and perhaps other components as well. The first occurrence was when the samples were shipped out to the medical center for Micro CT imaging, where D#00 was accidentally packed and sent to them despite the samples not being complete and ready. This may have caused the samples to be exposed to warmer temperatures than desired for a longer period of time compared to the rest of the donors; however, the samples appeared to be sufficiently cold once shipped back to the lab, indicating that there should be no significant issues relating to tissue degradation.

The second occurrence was when we were adjusting the pH of the solutions during the incubation stage. Initially, we were adjusting the pH using a diluted solution of NaOH; however, the volume increased dramatically due to the drastic changes in pH during the first few days. This could potentially influence the incubation of the samples since the addition of water may have diluted the rest of the chemicals in the solution and thus possibly changing the outcome of its effectiveness.

Overall, the project is still ongoing as there are more stages required for testing and collecting data from the samples that will be conducted throughout the fall semester; this includes mechanical 3-point bending tests, micro indentation, cRPI, and fAGE measurements.

 

References

1. Karim L, Bouxsein ML. Effect of type 2 diabetes-related non-enzymatic glycation on bone biomechanical properties. Bone. 2016;82:21-27. doi:10.1016/j.bone.2015.07.028
2.  Valcourt U, Merle B, Gineyts E, Viguet-Carrin S, Delmas PD, Garnero P. Non-enzymatic glycation of bone collagen modifies osteoclastic activity and differentiation. J Biol Chem. 2007;282(8):5691-5703. doi:10.1074/jbc.M610536200
3. Wongdee K, Charoenphandhu N. Update on type 2 diabetes-related osteoporosis. World J Diabetes. 2015;6(5):673-678. doi:10.4239/wjd.v6.i5.673
4. Singh, R., Barden, A., Mori, T. et al. Advanced glycation end-products: a review. Diabetologia 44, 129–146 (2001). https://doi.org/10.1007/s001250051591
5. Karim L, Moulton J, Van Vliet M, Velie K, Robbins A, Malekipour F, Abdeen A, Ayres D, Bouxsein ML. Bone microarchitecture, biomechanical properties, and advanced glycation end-products in the proximal femur of adults with type 2 diabetes. Bone. 2018;114:32-9. Epub 2018/06/02. doi: 10.1016/j.bone.2018.05.030. PubMed PMID: 29857063; PMCID: PMC6141002.
6. Karim L, Vashishth D. Heterogeneous glycation of cancellous bone and its association with bone quality and fragility. PloS one. 2012;7(4):e35047. doi: 10.1371/journal.pone.0035047. PubMed PMID: 22514706; PMCID: PMC3325937.
7. Poundarik AA, Wu PC, Evis Z, Sroga GE, Ural A, Rubin M, Vashishth D. A direct role of collagen glycation in bone fracture. Journal of the mechanical behavior of biomedical materials. 2015;52:120-30. Epub 2015/11/05. doi: 10.1016/j.jmbbm.2015.08.012. PubMed PMID: 26530231; PMCID: PMC4651854.
8. Tang SY, Zeenath U, Vashishth D. Effects of non-enzymatic glycation on cancellous bone fragility. Bone. 2007;40(4):1144-51. doi: 10.1016/j.bone.2006.12.056. PubMed PMID: 17257914; PMCID: PMC4398019.
9. Vashishth D, Gibson GJ, Khoury JI, Schaffler MB, Kimura J, Fyhrie DP. Influence of nonenzymatic glycation on biomechanical properties of cortical bone. Bone. 2001;28(2):195-201. PubMed PMID: 11182378.
10. Research centers. BIDMC of Boston. https://www.bidmc.org/research/research-centers. Accessed September 8, 2022.
11. Voziyan PA, Khalifah RG, Thibaudeau C, Yildiz A, Jacob J, Serianni AS, Hudson BG. Modification of proteins in vitro by physiological levels of glucose: pyridoxamine inhibits conversion of Amadori intermediate to advanced glycation end-products through binding of redox metal ions. J Biol Chem. 2003 Nov 21;278(47):46616-24. doi: 10.1074/jbc.M307155200. Epub 2003 Sep 15. PMID: 12975371.
12. Abar O, Dharmar S, Tang S. The effect of aminoguanidine (AG) and pyridoxamine (PM) on ageing human cortical bone. Bone & joint research. 2018;7(1):105-10.

 

 

‘Just Like Everyone Else’: Queer Representation in Post-Millennial Bollywood

 

By Nikki Sylvia

Portrait of Nikki (Paige) Silva

 

I am a Psychology major and member of the Psi Chi honor society. In Spring 2021, I took a course on “Gender and Sexuality in Bollywood Films,” with Professor Anupama Arora (English & Communication; Women’s and Gender Studies). In this course, we watched popular Hindi-language Indian films from the mid-twentieth century to the present. For my final research paper, I focused on two recent films that focused on same-sex love/desire, a subject rarely dealt with in classical Hindi/Indian cinema. I presented a version of this paper at the annual conference of the National Council of Undergraduate Research (NCUR) which was held virtually in April 2022; and I am grateful to the Office of Undergraduate Research at UMassDartmouth and the CAS Dean’s Office for supporting me. Furthermore, along with Prof. Arora, we have developed this paper into a longer co-authored journal-length article, which is currently under review at a scholarly academic journal.

 

The paper is titled “‘Just Like Everyone Else’: Queer Representation in Post-Millennial New Bollywood.” In a film industry where representations of heterosexual romance reign supreme and where explicit or sympathetic portrayals of non-normative desire or sexualities, while existent, have been marginal and few and far between, two recent films in particular stood out to me for their unapologetic expression of gay and lesbian struggles: Shelly Chopra Dhar’s Ek Ladki Ko Dekha Toh Aisa Laga (How I felt When I Saw That Girl, 2019) and Hitesh Kewalya’s Shubh Mangal Zyaada Saavdhan (Be Extra Wary of Marriage, 2020). These films followed in the wake of a historic legislation in India: on September 6, 2018, after decades of queer activism, Section 377 of the Indian Penal Code (the centuries-old law against sodomy) was declared unconstitutional by the Supreme Court of India.

 

The essay examines these two films as milestones of sorts in queer representations in post-millennial Bollywood. It shows how the films seek to disrupt the larger discourse around nonconforming gender/sexual subjects in popular Hindi cinema. Both films bring attention to, and contest, discourses around homosexuality in India that pathologize it – as unnatural, abnormal, filthy/dirty, disease/sickness, a crime, or as a Western import. The films make complex maneuvers to normalize same-sex love, and incorporate queer identity in ways that render it non-threatening to the heteronormative status quo. However, through their intertextual interventions (allusions to many other popular Hindi films and the conventions of this cinema), both these Bollywood “malltiplex” (mall + multiplex) films carry the potential of unsettling the dominant cis-heteropatriarchal order and imperatives of Hindu Indian society reflected in popular cinema. Thus, these recent films, even with some of their shortcomings, are refreshing for breaking the barriers of same-sex visibility in mainstream Indian cinema and can be seen as critical steps toward broader acceptance of queer identities and relationships.

Determining relative growth rates of bacterial isolates from marine biofilms

This work was conducted in the lab of Dr. Moisander, Department of Biology

By Andrea Pires

Andrea Pires at work in Dr. Moisander’s lab

 

Abstract

Biofilms of marine bacteria develop within hours of any surface submersed in seawater. Over the course of days and weeks these biofilms of bacteria mature to include protists, algae, cyanobacteria, and eventually unicellular and multicellular eukaryotes. Mature biofilms can interfere with marine operations such as boating and aquafarms, at which point they are referred to as biofouling. Antifouling methods have been developed to prevent biofouling, the most common of which involves coating the submersed surface with specialized toxic paint (de Carvalho, 2018). However, current antifouling methods are expensive and can be harmful to the environment. Potential targets for alternative antifouling methods could be found in the formation of biofilms at their early stages. There are many factors that are involved in early biofilm formation such as relative growth rates influencing bacterial fitness. This study focused on characterizing growth rates of 18 strains of marine bacteria recently isolated and identified from marine biofilms in Buzzards Bay. These cultures include bacteria from the Gammaproteobacterial genera Alteromonas, Pseudoalteromonas, Cobetia, Marinomonas, Salinimonas, Oceanobacter and Shewenella. The relative growth rates of the cultures were obtained through a series of 24-hour growth experiments. The estimated growth rates ranged from a minimum of 0.0847 h-1 to a maximum of 0.489 h-1. Significant differences in the growth rates among experiments were found for some strains. Significant differences were also found among the growth rates of strains within the genera Pseudoalteromonas, Salinimonas, and Shewenella but not among strains of Alteromonas sp.

 

Introduction

Biofilms are communities of adhered cells formed by bacteria and other microorganisms that cooperate to increase their chances of survival. In the marine environment, any submersed surface will rapidly develop a biofilm of bacteria that eventually matures to include other microorganisms such as protists, cyanobacteria and algae (de Carvalho, 2018). Advanced biofilms develop into biofouling, whose growth on submersed surfaces such as ship hulls and pipes can interfere with marine operations. For instance, the development of biofouling on ship hulls increases fuel consumption and fossil fuel emissions (Schultz et al., 2011). Various actions have been taken to eliminate biofouling, known as antifouling methods. The most common of these antifouling methods includes specialized toxic paint, which have their own negative impacts through toxicity to surrounding biota (de Carvalho, 2018). However, the costs and environmental impact associated with the development of biofouling and its prevention are substantial. Therefore, it is of interest to investigate the early stages of biofouling for purposes of exploring new potential targets for more affordable and environmentally sustainable antifouling methods.

In the initial stages of biofilm formation marine bacterial organisms colonize the submersed surface allowing for the adherence of successive colonizers such as protists and algae (de Carvalho, 2018). Targeting these initial bacterial colonizers could be an effective way to stop the development of biofouling at the source. However, more knowledge is needed about the growth dynamics of the initial biofouling colonizers. To begin, the relative growth

 

rates of 18 culture isolates of marine bacteria established and identified recently from marine biofilms in Buzzards Bay were investigated. All cultures used are common community members during early colonization of local marine biofilms (Naik et al., 2022). The methods and data from this experiment will help develop model systems for examining growth of initial biofouling colonizers and for designing further studies on impacts of antifouling methods on these bacteria.

 

Methods

 

Experimental Design

Reviving glycerol stocks

All culturing was conducted in a biosafety hood treated beforehand with ultraviolet light for at least 15 minutes. Sterile 5-mL tubes were used to revive the cultures from the glycerol stocks. The tubes were filled with 2.5-mL of marine broth. The glycerol stocks of the cultures were stored at -80ºC. The glycerol stocks of the cultures were kept on ice and using sterile, single-use inoculating loops, a small amount of the stock was obtained and transferred into its corresponding sterile 5-mL tube in the biosafety hood. The inoculated tubes were grown overnight (~24 hours) in a dark incubator at ~25-28ºC on a stirring plate.

 

Measuring Optical Densities (OD)

The next day, the optical densities of the overnight growth cultures were measured, and each strain was streaked on a Marine Agar plate (Fig. 1). 200 µL of each culture were added onto three wells of a non-treated polystyrene plate and read at 600 nm with a plate reader. These optical densities were then used to calculate the dilution factor for an OD of 0.05 and a total volume of 1000 µL. Using the subsequent dilution factors, a specific amount of each culture and Marine Broth were added to 2-mL sterile tubes. The optical densities of these dilutions were then measured again and recorded.

 

24-hour Growth Experiment

To prepare for the 24-hour growth experiment a plate lid was treated with 0.05% Triton X-100 in 20% ethanol to alleviate condensation forming in the lid throughout the 24-hour incubation. Each culture, adjusted to the approximate OD 0.05, further diluted with media to 1:100, was

 

aseptically pipetted to six replicate wells of a 96-well polystyrene plate. Each plate also included six wells with media only, serving as a negative control. The treated plate lid was then placed on top of the plate. The plate was then placed inside the microplate reader and grown at 25ºC. The plate reader program was adjusted to record optical density at 600 nm every 20 minutes for 24 hours. These readings were saved and used to estimate the growth rates of the marine bacterial cultures.

 

Estimating Growth Rates

The optical density readings recorded from the 24h growth experiments were then used to estimate the maximum growth rates of each strain and replicate (each well). The Easy Linear function within the R growthrates package was used to fit a linear model to the log- transformed data to find the maximum growth rate separately for each well, resulting in six separately calculated growth rates per strain per experiment (Petzoldt, 2020).

 

Results

The 24h growth overnight experiment was performed for each of the bacterial cultures at least once and up to seven separate times. The untransformed growth curves obtained by the 24h experiments were plotted for each experiment using the R growthrates package (Fig. 2). The estimated maximum growth rates ranged from a minimum of 0.0847 h-1 to a maximum of 0.489 h-1 across all strains and replicates (Table 1).

One of the aims of the experiments was to assess the methodological repeatability of the growth rate measurements across experiments. The variability in maximum growth rates of strains among experiments was analyzed using a series of one-way ANOVAs (Fig. 3). Growth rates of strains 9214 and 9273 were significantly different across experiments (one-way ANOVA, p < 0.05). Strains 9213, 9212, 9243 and 9275 were tested only once and the remaining strains showed no significant differences across experiments (one-way ANOVA, p>0.05). The growth rates of strains within the same genus were also compared using a series of one-way ANOVA tests. The Pseudoalteromonas genus included strains 9206, 9207 and 9274. There was a significant difference in the growth rates of strains 9206 and 9274 but other strains showed no differences. The Alteromonas genus included strains 9211, 9215, 9239, 9243, 9273, 9282, and 9283, and had no significant differences in their growth rates (p >0.05, Fig. 4). The Shewanella genus included strains 9242 and UMD1 with significantly different growth rates (p<0.05). The Salinimonas strains included strains 9275 and 9278 that also differed significantly in their growth rates.

 

 

Discussion

This study characterized growth rates of 18 recent marine biofilm bacterial isolates in the form of growth curves under standardized conditions. Calculated growth rates were used to examine any differences among the strains with respect to their growth patterns in monocultures. Variability across experiments is indicative of the reproducability and reliability of the growth rates obtained using this method. The data obtained from the growth experiments showed there was variability among experiments and strains within the same genus. However, only a few strains showed significant differences among experiments. For instance, strain 9213 showed significant differences in growth rates among experiments. This could have been influenced by the fact that it was later found to be a mixture of two different bacteria. Sources of variation within a single strain across experiments appear to have stemmed from periodically poor success in initial revival from glycerol or possibly experimental error.

Increasing the number of replicates per strain could help assess sources of variation among experiments.

There were significantly different growth rates among strains of the Pseudoalteromonas, Shewanella and Salinimonas genera but none were seen in the Alteromonas genus. These identified differences are likely due to slight functional differences among the strains but also could indicate more consistent differences among genera. Such differences may play a role in individual strain fitness in marine biofilms and will be of interest in future studies. Alteromonas spp. form a dominant component of early biofilms in local waters, while Shewanella spp. form a more subdominant group (Naik et al. 2022). A generally lower growth rate of Alteromonas was observed compared to Shewanella under the nutrient enriched conditions in these experiments and appears not to support the idea that representatives of Alteromonadaceae win during early biofilm colonization due to their superior growth rates.

Ultimately, these results will inform the growth curve methods and strains used in future experiments investigating biofilm formation along with competition and facilitation in co-cultures.

 

References

de Carvalho, C. C. C. R. (2018). Marine Biofilms: A Successful Microbial Strategy With Economic Implications. Frontiers in Marine Science, 5. https://www.frontiersin.org/article/10.3389/fmars.2018.00126

Naik, A., Smithers, M., & Moisander, P. H. (2022). Impacts of UV-C Irradiation on Marine Biofilm Community Succession. Applied and Environmental Microbiology, 88(4), e02298-21. https://doi.org/10.1128/aem.02298-21

Petzoldt, T. (2020). Estimation of Growth Rates with Package growthrates. https://tpetzoldt.github.io/growthrates/doc/Introduction.html

Schultz, M. P., Bendick, J. A., Holm, E. R., & Hertel, W. M. (2011). Economic impact of biofouling on a naval surface ship. Biofouling, 27(1), 87–98. https://doi.org/10.1080/08927014.2010.542809

 

Architecture and Morality in Antebellum New Bedford

 

By Kayla Rausch

 

Portrait of Kayla Rausch at work in New Bedford Public Library’s Special Collections

 

Does architecture manifest social and moral principles? Can we equate ethics with aesthetics? How can historical architectural styles reveal the values of societies in which they were built? My name is Kayla Rausch, a third-year Art History major, and I am the Fall 2021/Spring 2022 recipient of the New Bedford Art Museum/Artworks! Student Fellowship. Under the supervision of my advisor, Dr. Pamela Karimi, I have been developing my research project entitled Architecture and Morality in Antebellum New Bedford. Because it was home to some of the most affluent in antebellum America, New Bedford, MA, is an ideal location for studying the moral and ethical dimensions of stylistic preferences in American architecture.

My project examines how local architecture was emblematic of the esteemed values upheld by influential and affluent citizens of New Bedford during its Whaling boom in the pre-Civil War era. Amidst such prosperous conditions, the Society of Friends or Quakers—who had fled England to escape religious persecution during the 1600s— embraced simplicity and rejected excess ornamentation in their architecture. Contrasting the opulent Greek and Gothic-revival or the Second Empire styles, which were built and owned by other prosperous New Bedford whaling captions and businesspeople, New Bedford Quakers’ preference for modesty demonstrated that, even within the same society, there were differing ideas of morality and taste.

Examining how the Quakers’ values (which are visually depicted through their architecture) starkly contrasted the elitist ideals promoted through the surrounding structures, I embarked on a tour of the New Bedford Friends Meetinghouse and conducted interviews with experts and members of the Society of Friends. I learned from them how simplicity and transparency are at the heart of their values. Additionally, I have studied how Quakers have long been strong advocates of social activism and committed to racial equality as quintessential components of their faith. Specifically, Quakers played a major role in the abolitionist movement in New England. Though not all Quakers publicly participated in the abolitionist movement, they helped create a safe haven for runaway slaves who came to Massachusetts from the southern states. Quakers also advocated for gender equality, encouraging women to participate in businesses while their men were away and busy with whaling. My research aims to demonstrate how many of these values were manifested in both public and private buildings built and owned by Quakers.

In addition to extensive fieldwork, I have made numerous visits to the New Bedford Free Public Library to investigate nineteenth century society and Quaker history. The library has also afforded me an examination of mainstream nineteenth-century materials, such as architectural pattern books, popular magazines, and early twentieth century New Bedford city atlases. In order to foster a society centered upon the distinguished tastes of the wealthy, many nineteenth century publications worked to promote sophisticated European tastes. These included popular periodicals, such as Godey’s Lady’s Book and architectural pattern books, such as Asher Benjamin’s The Architect. These materials were all popular in antebellum New England and largely accessible to the New Bedford population.

 

By comparing and contrasting a wide range of published materials, I have examined which moral values were predominantly promoted and to what end. Given the significant role the Quakers played in all aspects of life in Antebellum New Bedford, I have further explored the reasons behind the marginalization of the Quaker aesthetic preferences in the mainstream and canonical discourse of American architecture.

I have presented my work to the fellowship committee and have been invited by the Director of Fine Arts at the New Bedford Public Schools to deliver a talk about my work to younger students.

As mentioned above, this project was awarded the 2022 New Bedford Art Museum/Artworks! Fellowship. In addition, I was a recipient of the Winter/Spring 2022 Office of Undergraduate Research (OUR) award. This grant has provided me the opportunity to conduct research about domestic and Quaker architecture of greater New England at the Boston Public Library as an extension of my project through the New Bedford Art Museum/Artworks! Fellowship. According to my mentor, Professor Karimi, “Kayla’s project is a great example of the high quality of research that undergraduate students at UMass Dartmouth undertake.” I soon plan to publish my work to an undergraduate journal. I also hope to go to graduate school to further study architectural and art history.

 

 

Risk-Induced Behavioral Changes Increase Survival When Exposed to Predators

By Isabella Mancini 

 

     Portrait of Isabella Mancini, her colleagues, and mentor,

Prof. Michael Sheriff, at Benthic Ecology Society’s annual meeting

in Portsmouth New Hampshire

 

Abstract

Predation risk is a pervasive force in ecology, shaping species interactions and community dynamics. When prey are exposed to predators they may alter their behavior, physiology, or morphology. Risk-induced behavioral changes can include changes to prey refuge use and risk aversion behavior. I hypothesized that the strength of these non-consumptive effects and prey behavioral decisions may depend on resource availability or prey state. I tested this by either exposing the dogwhelk, Nucella lapillus, to non-lethal green crabs, Carcinus maenas (rendered non-lethal by gluing their claws together) or not, for 28 days while varying food availability using the basal resource, Mytilus edulis. We measured individual behavior of Nucella every 3 days throughout the experiment. We also measured initial and final tissue weights, shell weights, and shell lengths of each Nucella in order to track growth. We found that risk-exposed Nucella were more risk averse. We also found that food availability increased risk aversion regardless of risk treatment. Food availability also significantly increased individual growth compared to non-food treatments. I found that there was a cost of predation risk on individual growth when compared to non-risk treatments, however initial prey state did not significantly impact risk aversion, nor did growth. These findings support the hypothesis that resources increase prey state enough to decrease risky behavior when faced with predation risk.

 

Introduction

The influence of predation risk on prey species and communities has become an emerging topic of study in the field of ecology. The risk of predation alone (not including consumption or killing) can alter prey phenotype, fitness, and influence species interactions within entire trophic chains (Peacor et al. 2020). These risk-induced responses may also be impacted by the environment in which they occur and may vary based on individual prey state or condition (Matassa et al. 2016). Learning the nuances of these prey responses is important to understanding the trophic relations and population dynamics in these systems.

Using a notable set of predator-prey interactions in the New England intertidal ecosystem, green crabs (Carcinus maenas) and dog whelk snails (Nucella lapillus), we investigate a novel area of this research: how prey decide to allocate their energy to either foraging or antipredator behaviors. Literature on how resource availability may impact refuge use behavior is lacking in its investigation into the decision a prey would make if the resources are outside of the refuge.

A 2016 study on Nucella, using barnacles as a resource, concluded that food outside of the refuge was enticing prey to engage in more risky behavior in the presence of risk and found that prey state did not dramatically affect this result (Matassa et al. 2016). The impact that food quality and handling time could have on this result is still in question. The alternative hypothesis that available resources could increase prey state, allowing them to stay in the refuge more often, has also not been thoroughly explored.  Here we expand upon the Matassa et al. (2016) study to examine individual level risk aversion behavior and growth when prey are exposed to predation risk or not across two different resource levels during a 4-week mesocosm experiment. We considered both resource availability hypotheses and made predictions that would support each.

 

Methods

Experimental design

We tested the influence of resource availability on prey refuge use behavior using a mesocosm laboratory experiment at the UMass Dartmouth School for Marine Science and Technology campus in New Bedford, MA. 15 Nucella, 10 of which were tagged and used for this experiment, (15.6 ± 1.3 mm, mean shell length ± SD) were placed in each of 24 clear-plastic mesocosms (44.45 cm. L x 30.48 cm W x 17.78 cm H) with independent flowthrough sea water (Buzzards Bay, ~ 18℃) and a 20.32cm² tile refuge elevated 2cm from the mesocosm floor by PCV pipe. The refuge could be accessed by Nucella but was too low for Carcinus to fit under. Snails could also access the top of the wall and underside lid of the mesocosm for refuge, as crabs could not attack them there (tested, but data not shown). 12 of the mesocosms had a single non-lethal green crab (52.2 ± 0.8 mm, mean carapace width ± SD with its claws banded and super glued shut to ensure they could not consume snails) and 12 mesocosms had blue mussels added as a resource (ad libitum) for a fully crossed 2×2 experiment, including: 6 food plus predation risk (FPR), 6 food no risk (FNR), 6 no-food plus predation risk (NFPR), and 6 no food no risk (NFNR) treatments. The experiment was conducted for 28 days from 7/19/21 to 8/18/21

We recorded snail location every 3 days for all tagged snails. Our designation of in a refuge or in the open was based upon those from Matassa et al. 2016, however, we also conducted preliminary feeding trials with crabs to determine where they could access and consume prey by attaching food (fish) to various locations on the wall and underside of the mesocosm lid. Snail location observations were scored as a -1 if snails were on the tile, in the open or low on the wall where they could be eaten, a 0 if snails were mid-way on the wall where crabs had difficulty accessing them, or a 1 if snails were under the tile, at the very top of the wall or the underside of the lid where crabs could not access them. The sum of the scores was used to estimate individual risk aversion scores for each tagged snail over the 28 days of the experiment. Shell and tissue weights of each tagged snail were taken using a non-destructive buoyant weighing technique (Palmer, 1982) and shell length was recorded using digital calipers. The weights and shell lengths were taken at the beginning and end of the experiment, and growth was calculated as the final-initial measurements.

 

Results

Pairwise comparisons were made between treatment groups and risk aversion score averages (Fig1). There was a significant difference between the FR and non-food treatments (FR|NFC p<0.001, FR|NFR p<0.01, Fig1). There was also a significant difference between our food with risk and food with no-risk groups (FR|FC p<0.001, Fig1). Risk and food both independently and combined increased risk aversion score.  Pairwise comparisons were also made between each treatment and each of our growth metrics across the experiment, tissue weight, shell weight, and shell length (Fig2). Food availability significantly increased all growth metrics when comparing each food treatment to it’s corresponding no-food treatment (FC|NFC and FC|NFR p< 0.001, FR|NFC and FR|NFR p=0.003 Fig 2). Predation risk caused a significant cost in growth when comparing the food control and food risk treatments (FR|FR; tissue and shell weight growth p<0.001, shell length growth p=0.002, Fig2). Risk aversion averages were then compared to the initial state of individual based on each growth metric (Fig3). Risk aversion averages were also compared to overall growth across the experiment using each metric (Fig3). Although there appears to be a negative correlation between risk aversion and each metric in both cases, almost all of these trends were not statistically significant (p>0.05, Fig3) and no correlation was found between risk aversion and initial or overall growth (R² ~0.33).

 

 

Fig 1. Risk Aversion vs Treatment. This graph shows comparisons of each of the four treatment groups to the average risk aversion score of individual snails within that treatment. Asterisks indicate significance (**** p<0.001). Bars show Mean +/- SD.

 

 

 

Fig 2. Growth Metrics vs Treatment. These graphs show comparisons of each of the four treatments groups to the average growth for each growth metric (tissue weight, shell length, shell weight). Bars show Mean +/- SD.

 

Fig 3. Risk Aversion vs Initial State & Growth. These graphs show trends in risk aversion behavior in comparison to trends in individual initial body condition and in each growth metric. None of these comparisons were statistically significant. Lines show Mean +/- SE.

 

Discussion      

We found that food availability increases growth across all metrics. This means prey that have higher resources are able to grow more. This result occurred as expected, however by comparing the food treatment groups to each other, we are also able to show that predation risk causes a cost to growth. That is, the prey in the FR treatment grew less than the prey in the FNR treatment. This finding could easily be attributed to the negative impacts that predation risk is assumed to have on a prey’s ability to forage, however our remaining findings show that this assumption is not as simple as it seems.

A prey’s ability to prioritize and allocate energy between both foraging and antipredator behaviors has major implications for it’s ability to grow and increase it’s fitness. We found that both food and risk being present increase refuge use both independently and together. These results support the hypothesis that food availability increases prey state enough that they do not need to leave the refuge to forage as often. This is contradictory to the hypothesis (supported by the Matassa et al. 2016) that food availability would increase foraging and entice prey out of the refuge therefore decreasing risk aversion. If this was the case in our study, the lowest risk aversion score should’ve been seen in the FC treatment, but that was not the case. Instead we found that the lowest risk aversion behavior and least refuge use occurred in the NFC group.  There are many possible explanations for why our results support this alternative hypothesis in compared to the previous research. More investigation needs to be done into how the quantity and quality of resources available to prey impact their behavioral decisions. Studies considering the natural and baseline levels of refuge use or fear of predation within prey could also help give insight into these types of contradicting behaviors seen across studies and taxa.

§

 

My Experience at the Benthic Ecology Meeting

      Isabella Mancini at the Benthic Ecology Society’s annual meeting in

Portsmouth, New Hampshire

 

I was lucky enough to attend the Benthic Ecology Meeting in Portsmouth, New Hampshire as part of the Sheriff lab this semester and it was a very unique experience. As an undergraduate, being able to attend a conference like this was incredibly valuable. I got to see tons of presentations of other scientists’ work in the field of ecology and network with professionals. Along with presenting my own work as a poster, I was able to discuss my work with others, including the very people I had cited in my paper, which was amazing. This experience helped me to learn how the world of academia really works and allowed me to talk with people at all stages of their careers, which was extremely beneficial to my understanding of the steps it takes to build a career in the field of biology.

 

Reconstructing the History of the Hoover Dam for Cutting-Edge Pedagogical Purposes

By James Ristaino

 

James Ristaino is shown here helping users with the VR experience he helped

create along with a team of faculty and other student researchers.

 

§

 

My name is James Ristaino. I am a junior majoring in Animation & Game Arts here at the College of Visual and Performinf Arts at UMassD. For the past couple of years I have been a member of an interdisciplinary research team of faculty, graduate, and undergraduate students on a virtual reality (VR) educational game, which we like to call VR “serious game.” This team, which is consisted of a variety of experts from science, arts, humanities, and computer science, focuses on creating an immersive VR environment for Hoover Dam (https://vrhooverdam.com). Our immersive environment tells the story of the dam’s construction from the viewpoint of photographer Winthrop A. Davis, who moved to Las Vegas in the early 1930s to capture the dam’s construction process. A “serious” educational game, the project is focused on the history of the construction of what my group believes to be “one of the most iconic structures in the world.” We combine cutting edge-technologies with scholarship in the field of history to create what my group describes as “an interactive, 4-dimensional game that takes place within the landscape of the 1930s Black Canyon site where Hoover Dam was built.” The project is funded by a grant from the National Endowment for the Humanities and is headed by lead researcher and UMassd Professor of English & Communication, Dr. Anthony Arrigo, as well as Professor Scott Ahrens from UMassD’s Art & Design, Dr. Shakhnoza Kayumova from UMassD’s STEM Education, and Dr. Michelle Turk from the Department of History at UNLV. There are also students in our team, including Matthew Cormier who is a Ph.D. Candidate in Mathematics, Mya Ramirez, who is an Undergraduate Student in Animation & Game Arts, and myself.

 

Work produced by James Ristaino for the NEH-funded, collaborative, and

interdisciplinary research project on the Hoover Dam.

§

I have spent my time on this team as a 3D artist. I was given historic images as reference and was asked to replicate them in 3D. This process consists of importing references into the workspace, selecting a basic shape to begin with(like a cube, cylinder, or sphere), and working simply for as long as possible. Meaning, working in low-detail, then adding high-detail later on. Once the model is complete, then it will need to be UV mapped, which means creating a surface mesh for the textures to be placed. The models are then brought into programs like Substance painter and materials are assigned to those UV maps to achieve the desired texture. An example of my work is the 1930’s Sixty Dozer, with 3 different texture options so that they don’t all look the same throughout the Canyon. I also worked on the Rope and Chair Hoisting system that the High-Scalers used during construction of the Dam, the Wrench that the workers used, and also the employment badge. I used a combination of materials on these models, like rust or metal, and photos to make the items look realistic, like the employment badge.

§

I have enjoyed my experience with the research team so far. I believe that this extracurricular activity has shaped my current career in the arts as well as possibly the future direction of my career in the field. I am grateful for this NEH-funded research opportunity! It is also wonderful to be guided by professors and researchers in learning environments outside the classroom context. I am particularly thankful to professors Arrigo, Ahrens, and Kayumova.

 

Self-Care Behaviors as a Mediator of Health Anxiety for Nurses during COVID-19 Pandemic

By Christopher McGuire

 

                      Chris McGuire at the Eastern Psychological 
                            Association’s Research Conference

Introduction

The COVID-19 pandemic has lead to many adverse psychological outcomes, especially in healthcare workers. For example, nurses working with COVID patients report higher symptoms of PTSD, anxiety, and insomnia (Li, 2021; Schierber-Scherr et al., 2021). Health anxiety, another negative outcome, is defined as the preoccupation or obsession with thinking an individual has a serious physiological disease when there are no apparent physical symptoms (Weck & Höfling, 2015). This can develop into a serious mental disorder that overtakes one’s thoughts and emotions if symptoms get out of control, thus interrupting their daily life. To mitigate such adverse outcomes, self-care behaviors are essential to maintain physiological health (Riegel, et al., 2009). In this study, differences in health anxiety levels will be measured in nurses who have worked with COVID-19 patients and nurses who have not, and self-care behaviors will be tested as a moderator of those two variables.

Methods

Participants

For four weeks in October and November, 2021, nurses were invited to participate in our study by taking online surveys promoted through social media and the American Association of Critical Care Nurses Participate in Research Studies webpage. A total of 271 responses were recorded, but only 148 responses were used in the analysis due to missing data. Participants were asked demographic information, including number of years worked as a nurse, age, average number of hours worked per week, and whether or not they have worked directly with patients who had contracted COVID-19.

Measures

Health Anxiety: Participants were asked to complete the Health Anxiety Questionnaire (HAQ) (Lucock & Morley 1996) to measure their levels of health anxiety. The survey consists of 21 questions asking participants about their attitudes towards their own physical health, and health symptomologies. The items can be categorized into four subscales (health worry & preoccupation, fear of illness & death, reassurance seeking behavior, and interference with life) or scored as a full scale. The HAQ uses a 4-point Likert scale (scored 0-3) ranging from “not at all or rarely” to “most of the time” to measure how often the participants feel concern, anxiety, or stress about their own physical health. The average scores were used in the current analyses, with higher scores indicating higher health anxiety.

Self-care: A self-care measure was developed by the researchers for the study to assess  15 self-care activities, including sleep, exercise, diet, stress management, and body monitoring. Items on the self-care measure were loosely based off the Self-care of Heart Failure Index (SCHFI) (Riegel, et al., 2009) which asks a variety of self-care questions using various Likert scales. Higher scores indicate an increased frequency in engaging these behaviors.

Results

Data were analyzed in two steps. The first step was to examine differences in health anxiety. Specifically, a t-test found that nurses who reported treating patients with COVID-19 had significantly higher health anxiety scores (M = 2.77, SD = 0.67) than nurses who did not (M = 2.39, SD = 0.50), t(147) = 3.04, p = .003). The second step was to examine if self-care behaviors moderated the relationship between treating patients with COVID-19 and health anxiety. We tested this using a hierarchical regression controlling for age, number of years working as a nurse, and education. The first step, which included the control variables, if they treated patients with COVID-19, and scores on the self-care scale, accounted for 21.7% of the variance, F(5, 142) = 7.88, p < .001. The second step, which included the interaction term of if they treated patients with COVID-19 and self-care, accounted for an additional 2.2% of the variance, ΔF(1, 141) = 4.07, p = .04. Overall, the model accounted for 23.9% of the variance in health anxiety, F(6, 141) = 7.83, p < .001. Follow-up analyses of the interaction found that the difference in health anxiety between nurses who treated patients with COVID-19 and those who did not decreased as self-care behaviors increased.

Discussion

Working closely with patients with COVID-19 during a national pandemic is significantly related to increased levels of health anxiety in nurses. This finding emphasizes the vulnerability of nurses working with COVID patients to adverse psychological outcomes. Self-care behaviors may be an effective way to lower these levels of health anxiety. Self-care behaviors accounted for a significant amount of variance of health anxiety in nurses that worked with COVID patients. This suggests that engaging in healthy self-care acts can help reduce feelings of health anxiety in nurses working with COVID patients. Lastly, as self-care behaviors increased, the differences in health anxiety decreased between nurses who treated COVID patients and nurses who did not. This suggests self-care behaviors are essential to maintain lower health anxiety levels for all nurses, but that they might be particularly important for nurses who treat patients with COVID-19.

The current study emphasizes the need for nurses to engage in self-care behaviors, especially those working with patients with COVID-19. Limitations of this study include the use of self-report, that the sample is not representative (e.g., geographical area, sample was overwhelmingly White and female), and that it is possible that nurses who were more affected by the COVID-19 pandemic may have been more likely to respond. Future research is needed for more in-depth knowledge of the adverse effects of health anxiety on nurses working with COVID patients.

Presentation at the Eastern Psychological Association’s research conference: A Fulfilling Experience

Walking into the Eastern Psychological Association’s research conference, I was unsure what to expect as this was my first time ever at a conference. I was walking through Times Square to my hotel in Manhattan, a city I have never been before, wondering what kind of experience I would have. Outside, the typical hustle and bustle of New York City was going on in the streets, but on the inside, a solemn sharing of knowledge was taking place. It was a very unique sight, as students, professors, and researchers from around the US met in this somewhat chaotic city to share research, ask questions, and speak with like-minded people.

I had the pleasure of listening to some great speakers and speaking with dedicated students during the two full days of the conference before my own presentation. I particularly enjoyed walking around the poster presentations and seeing what other students were researching. I was truly amazed at the number of undergraduates who were attending their first conference, like myself. Listening to keynote speakers with decades of experience was also fascinating as these researchers are at the top of their field and show me what I can become with dedication and hard work. The highlight of my conference experience was presenting. I was a bit concerned while setting up my poster, but once I started speaking to the viewers, the nerves melted away and it truly felt like having a conversation rather than a “presentation.” Overall, my first conference was a memorable experience and something I will take with me the rest of my career. I learned a lot, was amazed by the environment and amount of knowledge, and was very proud to show my project I have been working on for over a year to viewers. I thank my mentor, Dr. Brian Ayotte, my committee members, Dr. Anna Shierberl Scherr and Dr. Marni Kellogg, the Office of Undergraduate Research, and my family for their support to make this experience happen.

Using the User Cost of Monetary Assets to Explain the Investment Portion of Gross Domestic Product

 

By Adam Bourgoin-Stone

Over the summer, I have been co-writing a paper with Dr. Biyan Tang on the merits of utilizing the user cost of monetary assets rather than the interest rate in economic research, specifically research into the investment part of Gross Domestic Product. The paper itself is not complete yet, and the current results may change if errors in the regression are detected.  The paper has been submitted to present in a conference hosted by the Midwest Economics Association. This project has been and continues to be an incredible opportunity for me to not only learn more about economics, but also expand my critical reading and research skills.

Gross Domestic Product is often used in economics as an indicator of general economic growth. GDP is equal to Consumption + Investment + Government Spending + Net Exports. According to the Bureau of Economic Analysis, investment has remained at between 16% and 26% since 1947. Since investment is a significant portion of GDP, it is important to understand which factors correlate with it, and which factors can promote its growth. Based on traditional economic theory, the interest rate is negatively related to the level of investment that firms are willing to make. In other words, with a higher interest rate, investment will fall assuming other economic or political conditions remain the same. However, the relationship between the interest rate and investment can be unclear. Some research in the past has found a negative relationship; some has found a positive relationship; one paper found that the correlation changes significantly based on the interest rate level at the time of adjustment. A more intuitive tool for measuring investment as a part of GDP may be the user cost of monetary assets. The user cost is measured by the opportunity cost, or the forgone interest, of holding certain liquid monetary assets (like currency or checking account balance) versus holding pure investment assets. For example, if you held $1000 in cash, the user cost of your monetary asset would be the federal interest rate that you could have earned on the money had you kept it entirely in the form of investment assets such as treasury bonds. The user cost of monetary assets can be separated into the user costs for the various monetary aggregates, such as M1, M2, M3, and M4. A general overview of the monetary aggregates is that M1 contains the most liquid assets, and that each subsequent monetary aggregate contains the previous aggregate plus less liquid assets. For example, M1 contains physical currency, demand deposits, traveler’s checks, and other checkable deposits. M2 contains everything in M1, and also savings deposits, money market securities, mutual funds, and other time deposits.

Barnett (1978) derives a user cost formula for monetary assets:

where p_it is the current period user cost of the per capita real balances of monetary asset i during period t, p^*_t is an aggregate index of the prices of good/services and of the prices of durable goods rental during period t, R_t is the yield on per capital bond holdings during period t, and r_it is the nominal yield on monetary asset i during period t. The formula demonstrates that as the benchmark interest rate rises, the forgone interest rate increases with it.

The relationships of different economic factors with investment can be described using the Ordinary Least Squares regression

PriInv = b0 + b1(IntRate) + b2(rGDP) + b3(PubInv) +b4(PriCredit) + b5(CorpTax) + b6(Income) + b7(Inflat) + b8(TreasBond) + b9(Savings)

where the dependent variable is private investment in billions of dollars, and the independent variables are the interest rate, real GDP, public investment, credit available to the private sector, the effective corporate tax rate, aggregate income, the inflation rate, the treasury bond yield rate, and the savings rate. The user cost data was organized by the user costs for the different monetary aggregates (e.g. M1, M2, M3, M4). Two regressions were used, one using the interest rate, and the other replacing the interest rate with the user cost of monetary assets for M1. The adjusted R², which is the percent of the variance of the dependent variable that is explained by the independent variables, was compared to determine whether the user cost is a better determinant of private investment than the interest rate. Regressions were run with the user cost for each monetary aggregate, with the regression that yielded the highest adjusted R², the user cost for M1, being compared with the interest rate regression. The t-values of the interest rate and the user cost for each monetary aggregate were used to determine the statistical significance of each variable’s correlation with gross private investment. The statistical significance of each monetary aggregate’s user cost and the interest rate is visualized in Figure 1. Clearly, the interest rate is shown to have the most statistically significant correlation with the investment, and the user cost for M1 is shown to have the most significant relationship out of all of the user costs, though it is still statistically insignificant. Figures 2 and 3 show the interest rate and the user cost of M1 over time with gross private investment, respectively. The user cost and the interest rate are shown to be almost identical in proportion.

Figure 1, t-values of the interest rate and the monetary aggregate user costs

 

Figure 2, gross private investment and the interest rate over time

 

Figure 3, gross private investment and the user cost of M1 over time

 

The coefficients of each of the variables of the regression using the interest rate are shown in Figure 4. In this regression the interest rate is found to have a positive correlation with private investment. While at first glance, this seems contrary to traditional economic theory, this is likely because we did not add a lag to the regression. The relationship is shown to be positive because when investments fall, the federal reserve lowers the interest rate to stimulate investment, and when investment rises again, the federal reserve slowly returns interest rates to their previous values. The effective corporate tax rate was also shown to have a positive correlation, when a higher tax rate would be expected to lower the funds firms have at their disposal to invest, thereby reducing private investment. Figure 5 shows the regression using the M1 user cost (as that is the user cost that had the most significant correlation with investment, and the regression using the M1 user cost yielded the highest adjusted R²). The effective corporate tax rate is shown to have a positive relationship in this regression as well. In fact, most of the variables have similar values to the regression using the interest rate, except for the treasury bond yield rate and the inflation rate.

Figure 4, regression results for the interest rate. Standard errors are below coefficient values. *** – significant at 1% level. ** – 5% level. * – 10% level

 

Figure 5, regression results for the user cost. Standard errors are below coefficient values. *** – significant at 1% level. ** – 5% level. * – 10% level

 

The adjusted R² of the regression using the interest rate was .9905, and the adjusted R² of the regression with the user cost was .9881. This result is not unexpected, given the fact that the user cost was found to be statistically insignificant, while the interest rate was found to be significant at the 0.1% significance level, meaning that there is only a 0.1% risk of concluding that it is significant when it isn’t.

According to these results, the interest rate is probably a better variable than the user cost for explaining the variance of investment in the US. Secondary results include the statistical insignificance of the inflation rate when explaining investment, and also the inconsistency of the treasury bond yield rate’s significance. When using the interest rate, it was found to be mostly insignificant, but when using the user cost for M1, it was found to be significant at or above the 1% level. Based on these current results, I cannot conclude that the user cost of monetary assets is a more efficient factor than the interest rate for analysis of the investment part of GDP.

I want to thank the Dean of the UMass Dartmouth College of Arts and Sciences, Dr. Pauline Entin, for the generous stipend that I was granted for my summer project.

Works Cited in Paper

Acha, Anthony, and Kelechi Acha. “Interest Rates in Nigeria: an Analytical Perspective.” Research Journal of Finance and Accounting, vol. 2, no. 3, 14 Apr. 2016, pp. 71–81.

Agu, Osmond Chigozie. “DETERMINANTS OF PRIVATE INVESTMENT IN NIGERIA: AN ECONOMETRIC ANALYSIS.” International Journal of Economics, Commerce and Management, vol. 3, no. 4, Apr. 2015.

Ahmed, Afaq, and Muhammad Mubarik. “Impact of Interest Rate and Inflation on Stock Market Index: A Case of Pakistan .” Jan. 2012.

Ajide, Kazeem, and Olukemi Lawanson. “Modelling the Long Run Determinants of Domestic Private Investment in Nigeria.” Asian Social Science, vol. 8, no. 13, 2012.

Akhtar, M. A. “Effects of Interest Rates and Inflation on Aggregate Inventory Investment in the United States.” The American Economic Review, vol. 73, no. 3, June 1983, pp. 319–328.

Albu, Lucian Liviu. “TRENDS IN THE INTEREST RATE–INVESTMENT– GDP GROWTH RELATIONSHIP .” Romanian Journal of Economic Forecasting, vol. 3, Jan. 2006, pp. 5–13.

Appienti, William, et al. “KEY DETERMINANTS OF INVESTMENTIN GHANA: COINTEGRATION AND CAUSALITY ANALYSIS.” May 2016.

Awan, Rehmat, et al. “Rate of Interest, Financial Liberalization & Domestic Savings Behavior in Pakistan.” International Journal of Economics and Finance, vol. 2, no. 4, 2010.

Bagci, Erdem, and Emre Erguven. “Relations between Interest Rate, Inflation, Growth AndInvestment in Turkey, 2002-2015 .” 2016.

Bitros, Georgios, and M. Ishaq Nadiri. “Elasticities of Business Investment in the U.S. and Their Policy Implications : A Disaggregate Approach to Modeling and Estimation .” July 2017.

Chen, K. C., and Daniel Tzang. “Interest-Rate Sensitivity of Real Estate Investment Trusts.” The Journal of Real Estate Research, vol. 3, no. 3, 1988, pp. 13–22.

Heim, John. “THE INVESTMENT FUNCTION: DETERMINANTS OF DEMAND FOR INVESTMENT GOODS.” Jan. 2008.

Kosma, Olga. “Determinants of Investment Activity: the Case of Greece.” 2015.

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