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Theses/Dissertations

University of Massachusetts Amherst

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Full-Text Articles in Life Sciences

The Efficacy Of Atp Monitoring Devices At Measuring Organic Matter On Postharvest Surfaces, Kristin Lane Jan 2019

The Efficacy Of Atp Monitoring Devices At Measuring Organic Matter On Postharvest Surfaces, Kristin Lane

Masters Theses

The Food Safety Modernization Act (FSMA), specifically the Produce Safety Rule (PSR), requires growers to clean and sanitize food-contact surfaces to protect against produce contamination. The ATP monitoring device is a potential sanitation tool to monitor the efficacy of an on-farm cleaning and sanitation program that could help growers meet regulatory expectations mandated by PSR. The ATP device uses bioluminescence to detect all ATP (found in bacteria and produce matter cells) from a swabbed surface. Little work has been done to test the efficacy of these tools under postharvest conditions. The present study evaluated ATP measurement for postharvest surface cleanliness ...


Metabolic Cost And Stability Of Locomotion In People With Lower Limb Amputation, Ryan Wedge Jan 2019

Metabolic Cost And Stability Of Locomotion In People With Lower Limb Amputation, Ryan Wedge

Doctoral Dissertations

It is generally accepted that metabolic energy expenditure and gait stability are key factors that influence the selection of able-bodied locomotor patterns. It is unclear how energy expenditure and gait stability are prioritized during walking in people with lower limb amputation. People with lower limb amputation generally have greater metabolic energy expenditure during walking and increased incidence of falls. People with unilateral lower limb amputation spend more time on the intact limb compared with the prosthetic limb, while able-bodied individuals generally walk with symmetrical timing between limbs. Restoring symmetry is often a goal of rehabilitation and assistive devices, yet the ...


Chemoreceptor Dynamics And Signaling: Nmr Measurements Within Functional Complexes, Maryam Kashefi Jan 2019

Chemoreceptor Dynamics And Signaling: Nmr Measurements Within Functional Complexes, Maryam Kashefi

Doctoral Dissertations

Bacteria employ remarkable membrane-bound nanoarrays to sense their environment and direct their swimming. Arrays consist of chemotaxis receptor trimers of dimers that are bridged at their membrane-distal tips by rings of two cytoplasmic proteins, a kinase CheA and a coupling protein CheW. It is widely accepted that ligand binding to the receptor causes a 2 Å piston motion of a helix that extends through the periplasmic and transmembrane domains. However, it is not clear how the signal propagates 200 Å further to control activity of the kinase bound at the tip of the receptor. Dynamic changes within the cytoplasmic domain ...


Feasibility And Efficacy Of A Recess-Based Combined Fitness Intervention On Cognition And Academic Performance In Elementary School Children, Christine St Laurent Jan 2019

Feasibility And Efficacy Of A Recess-Based Combined Fitness Intervention On Cognition And Academic Performance In Elementary School Children, Christine St Laurent

Doctoral Dissertations

Youth physical activity and fitness have been reported to influence cognition and academic related outcomes. Despite the potential benefits of muscular fitness, few intervention studies have examined the impact of an intervention that has incorporated both cardiorespiratory and muscular fitness training on cognition and academic performance in children. Previous studies have mainly been implemented either during the school day or immediately after-school. Although recess may be an ideal time to promote physical activity because it does not compete with other academic demands, it has been an understudied setting. Therefore, the purpose of this dissertation project was to examine the feasibility ...


Investigating The Role Of Lbh During Early Embryonic Development In Xenopus Laevis, Emma Weir Jan 2019

Investigating The Role Of Lbh During Early Embryonic Development In Xenopus Laevis, Emma Weir

Masters Theses

LBH is a highly conserved protein whose role during vertebrate development is relatively under-studied. In collaboration with the Albertson lab, our lab has previously shown that it is necessary for cranial neural crest cell migration in the zebrafish and in Xenopus laevis. The molecular mechanisms through which it acts are not well understood.

In Xenopus, LBH is a maternally deposited protein. As such, studying its role in early development has not been feasible through the morpholino-mediated knockdown techniques that prevent translation of target genes. Recently, a technique for degrading endogenous proteins was developed, called Trim-Away. This was developed in mammalian ...


An Examination Of Tern Diet In A Changing Gulf Of Maine, Keenan Yakola Jan 2019

An Examination Of Tern Diet In A Changing Gulf Of Maine, Keenan Yakola

Masters Theses

The Gulf of Maine is a dynamic ecosystem with rapidly warming sea surface temperatures (SSTs), therefore it is vital to understand how species interactions vary over time and space. In chapter two, I quantify and compare dietary differences among four tern species, across seven islands in the region, over a 32-year period. Multivariate statistical analyses were employed to discern spatial and temporal differences in foraging ecology. Findings suggest there are significant differences between species and islands; however, only three prey species comprise the majority of chick diet for all terns and islands. The reliance on only a few prey items ...


Optical Meets Mechanical: Use Of Luminescence Spectroscopy To Assess Ageing In Biodegradable Films, Louis Colaruotolo Jan 2019

Optical Meets Mechanical: Use Of Luminescence Spectroscopy To Assess Ageing In Biodegradable Films, Louis Colaruotolo

Masters Theses

With the growing concern of the accumulation of plastic-based food packaging waste, the search for bio-based biodegradable packages is on the rise. These materials differ from their petro-based counterparts in their degradation rates, which are much higher in the former. Not only do bio-based biodegradable materials degrade faster during post-usage processes but also they age faster during usage and storage, which affects their performance and functionality. The application of noninvasive testing methods with the capability to report on the matrix’s state could assist in the development of a more ubiquitous way to assess ageing in food packaging, particularly in ...


Drivers And Consequences Of Carbon Use Efficiency - And Its Measurement In Soil, Grace Pold Jan 2019

Drivers And Consequences Of Carbon Use Efficiency - And Its Measurement In Soil, Grace Pold

Doctoral Dissertations

Soils serve as massive carbon sinks, but their ability to continue this ecological service is contingent on how the resident soil microbial community will respond to the ongoing climate crisis. One key dimension of the microbial response to warming is its carbon use efficiency (CUE), or the fraction of carbon taken up by an organism which is allocated to growth rather than respiration. However, the scientific community is still in the early stages of understanding the drivers, consequences - and even accurate measurements of - CUE. In this dissertation, I first quantified the variability of CUE and its responsiveness to temperature and ...


Silver Mirror Substrate And Rolling Method For Improved Surface-Enhanced Raman Spesctroscopic Analysis In Food, Yanqi Qu Jan 2019

Silver Mirror Substrate And Rolling Method For Improved Surface-Enhanced Raman Spesctroscopic Analysis In Food, Yanqi Qu

Doctoral Dissertations

Surface-enhanced Raman spectroscopy, short for SERS, is an emerging technology with great potential in food analysis due to rapid detection, high sensitivity, portable instrumentation, and simple sample preparation. However, it is always a bottleneck to obtain reproducible SERS measurements in real analytical cases due to the complicity of food systems and inhomogeneous aggregation of colloidal nanoparticles. To improve its performance for practical applications in food analysis, efforts have been made in improving the reproducibility, enhancing the selectivity and reducing the matrix interference to the analyte. Herein, a self-assembly silver nanoparticles mirror substrate was fabricated to improve the and the quantitative ...


Factors Influencing Spartina Alterniflora Productivity In Relationship To Estuary Inlet Opening Ellisville Marsh, Plymouth, Ma, Ellen K. Russell Jan 2019

Factors Influencing Spartina Alterniflora Productivity In Relationship To Estuary Inlet Opening Ellisville Marsh, Plymouth, Ma, Ellen K. Russell

Doctoral Dissertations

A scientific basis for understanding the health of salt marsh vegetation, primarily Spartina alterniflora, in apposition to dredging of the tidal inlet to Ellisville Marsh in Plymouth, Massachusetts was determined. A three-hectare S. alterniflora loss, and coincident coastal bank erosion occurred; ostensibly due to inlet blockage from sand deposition, prolonged inundation, and meandering of inlet channel into coastal bank. This warranted dredging the tidal inlet, whereby tidal flushing would restore growth or discontinue die-off, and deter coastal bank erosion. A pre- and post dredge study was conducted assessing environmental factors related to plant productivity. Following dredging, an increase in tidal ...


Multiscale Simulations Of Intrinsically Disordered Proteins, Xiaorong Liu Jan 2019

Multiscale Simulations Of Intrinsically Disordered Proteins, Xiaorong Liu

Doctoral Dissertations

Intrinsically disordered proteins (IDPs) lack stable secondary and/or tertiary structures under physiological conditions. The have now been recognized to play important roles in numerous biological processes, particularly cellular signaling and regulation. Mutation of IDPs are frequently associated with human diseases, such as cancers and neuron degenerative diseases. Therefore, it is important to understand the structure, dynamics, and interactions of IDPs, so as to establish the mechanistic basis of how intrinsic disorder mediates versatile functions and how such mechanisms may fail in human diseases. However, the heterogeneous structural ensembles of IDPs are not amenable to high resolution characterization solely through ...


Physical And Biological Drivers Of Juvenile Fish Distributions In Unstructured Shallow Tropical Nearshore Habitats, Christopher Haak Jan 2019

Physical And Biological Drivers Of Juvenile Fish Distributions In Unstructured Shallow Tropical Nearshore Habitats, Christopher Haak

Doctoral Dissertations

The structural complexity of aquatic habitats can influence the ecological processes that occur within them, as fine-scale topographic features act as refugia for small fishes, buffering the effects of environmental stressors. Accordingly, the habitat requirements of juvenile demersal fishes in shallow littoral zones are often defined by their associations with distinct benthic microhabitats, such as densely vegetated substrates. However, an array of ecologically-important juvenile fishes also associate with topographically-homogeneous, sparsely-vegetated substrata. Absent the benefits offered by structural refugia, such fishes may be more affected by environmental variability and may have evolved distinct strategies for coping with stressors. I examined this ...


Arboriculture Safety Around The World, Jamie Lim Jan 2019

Arboriculture Safety Around The World, Jamie Lim

Masters Theses

Arboricultural work is inherently dangerous, with more serious injuries and fatalities than most other professions. Safety standards exist in some jurisdictions, but it is unclear how many standards exist, how they compare to one another, and whether (and how many) jurisdictions share standards. To establish a baseline understanding of these issues, my objectives were to (i) develop a database of existing standards, (ii) identify the most frequently occurring safety topics and (iii) describe similarities and differences in safety topics among standards from different countries. I worked with a variety of contacts and traditional university library resources to identify, obtain, analyze ...


Urban Biodiversity Experience And Exposure: Intervention And Inequality At The Local And Global Scale, Evan Kuras Jan 2019

Urban Biodiversity Experience And Exposure: Intervention And Inequality At The Local And Global Scale, Evan Kuras

Masters Theses

As cities expand globally, researchers must clarify how human activities and institutions shape biodiversity and conversely, how ecological processes shape human outcomes. Two features of contemporary cities motivate this thesis. First, urban residents, and especially children, are spending less time in nature and consequently, miss out on healthy and formative experiences with biodiversity. Second, residents with the least access to biodiversity tend to be those with the lowest socioeconomic status (SES). Together, these patterns convey a multi-layered environmental injustice: not only might urbanites become increasingly estranged from biodiversity, disinterested from its conservation, and disconnected from its benefits, but these outcomes ...


Population Viability And Connectivity Of The Federally Threatened Eastern Indigo Snake In Central Peninsular Florida, Javan Bauder Jan 2019

Population Viability And Connectivity Of The Federally Threatened Eastern Indigo Snake In Central Peninsular Florida, Javan Bauder

Doctoral Dissertations

Understanding the factors influencing the likelihood of persistence of real-world populations requires both an accurate understanding of the traits and behaviors of individuals within those populations (e.g., movement, habitat selection, survival, fecundity, dispersal) but also an understanding of how those traits and behaviors are influenced by landscape features. The federally threatened eastern indigo snake (EIS, Drymarchon couperi) has declined throughout its range primarily due to anthropogenically-induced habitat loss and fragmentation making spatially-explicit assessments of population viability and connectivity essential for understanding its current status and directing future conservation efforts.

The primary goal of my dissertation was to understand how ...


Changes In Color Guidance Over The Course Of A Complex Visual Search, Ryan Papargiris Jan 2019

Changes In Color Guidance Over The Course Of A Complex Visual Search, Ryan Papargiris

Masters Theses

When searching for an object, we store a mental representation of the target, which guides our search through the use of attention. The effectiveness of this search guidance varies depending on the task and the relationship between target and distractors. With a better understanding of how search guidance changes over time within a trial, we can better compare the differences between experimental conditions. Eye tracking data from a variety of search tasks were analyzed to determine how color guidance varied over the course of the trial. Color guidance for a given fixation was evaluated based on the distance in color ...


Visual Attention In Jumping Spiders, Margaret Bruce Jan 2019

Visual Attention In Jumping Spiders, Margaret Bruce

Masters Theses

The different ways that animals extract and analyze visual information from their environment is of interest to sensory ecologists. Jumping spiders, well-known for visually guided mating and hunting behavior, are an interesting model for the study of visual attention because they quickly and efficiently integrate information from eight eyes with a small brain. Stimuli in front of the spider are examined by two functionally and morphologically distinct pairs of forward-facing eyes. The principal eyes discern fine details and have small retinas and thus a small visual field. However, their position at the back of moveable tubes within the cephalothorax expands ...


Ecological And Economic Implications Of Establishing Quercus Spp. In The Urban Environment, Tierney Bocsi Jan 2019

Ecological And Economic Implications Of Establishing Quercus Spp. In The Urban Environment, Tierney Bocsi

Masters Theses

As urban greening efforts continue, it is important to assess whether decisions to intensify street tree planting are meeting intended goals of improving urban canopy cover and increasing ecosystem services. Benefits of the urban forest take many forms, from ecological and economic to social and cultural, and are frequently cited in support of street tree planting. However, it is unknown to what extent factors such as species or nursery production method affect the ability of trees to successfully establish and provide ecosystem services in the urban environment. Using a system of oak trees planted along roads in South Amherst, Massachusetts ...


Garlic Mustard (Alliaria Petiolata) Management Effectiveness And Plant Community Response, Erin Coates-Connor Jan 2019

Garlic Mustard (Alliaria Petiolata) Management Effectiveness And Plant Community Response, Erin Coates-Connor

Masters Theses

The control and eradication of the invasive biennial herb garlic mustard (Alliaria petiolata) and the restoration of invaded forest habitats present important linked challenges to land managers in North America. Removing garlic mustard by hand and by glyphosate herbicide application have both been used as eradication strategies with mixed results. Each method has advantages and disadvantages, but they are rarely compared for effectiveness and community impact across multiple years of management. Some previous studies have shown improvements in species diversity and plant community composition following management, while others have found no differences. To better understand both garlic mustard population and ...


One Year Change In Cognitive Function In Male And Female Common Marmosets (Callithrix Jacchus), Brianna Healey Jan 2019

One Year Change In Cognitive Function In Male And Female Common Marmosets (Callithrix Jacchus), Brianna Healey

Masters Theses

Long term cognitive studies in humans and nonhuman primates such as macaques are difficult because of their long lifespan. The common marmoset (Callithrix jacchus) is a non-human primate who shares with humans many features characteristic of primates, including a complex brain and cognitive function. They also have a short lifespan (~10 years) that makes them a great model in studies of cognitive aging. This study focuses on the rate of decline in cognitive function in male and female marmosets based on performance on reversal learning tasks over 2 years of testing.

We found that marmosets improved their overall performance from ...


Photosynthesizing The Workplace: A Study In Healthy And Holistic Production Spaces, Kaeli Howard Jan 2019

Photosynthesizing The Workplace: A Study In Healthy And Holistic Production Spaces, Kaeli Howard

Masters Theses

Throughout time nature has been a prescribed healer of stress on the human condition. Its vital integration into our daily lives has been proven by scientific evidence. The majority of Americans spend approximately 1/3 of their life working, whatever that job may entail. Therefore, it makes sense that the environments that we spend so much of our life in for work at extremely important to our physical and mental health, however, current workplace models are not acknowledging that. Redefining the workplace to integrate nature would start to change work life in this country and how work itself is viewed ...


The Efficacy Of Nanoemulsion-Based Delivery Systems To Improve Vitamin D3 Bioaccessibility And Bioavailability, Alagu Selvi Kadappan Jan 2019

The Efficacy Of Nanoemulsion-Based Delivery Systems To Improve Vitamin D3 Bioaccessibility And Bioavailability, Alagu Selvi Kadappan

Masters Theses

Vitamin D deficiency is an epidemic issue in all age groups in Western countries and that affects both skeletal and non-skeletal functions. Even with the wide application of food fortification, vitamin D deficiency tends to increase continuously. Being hydrophobic in nature, vitamin D has poor solubility; thereby it negatively affects its absorption and bioavailability when compared to other hydrophilic dietary compounds. The need to develop a novel strategy is of greater importance to enhance its bioavailability and thereby improving vitamin D level in the body.

In this study, lipid-based delivery of oil-in-water nanoemulsion (diameter < 200nm) was utilized to improve the bioaccessibility and oral bioavailability of vitamin D3. First, we examined the in ...


Studies On The Interaction And Organization Of Bacterial Proteins On Membranes, Mariana Brena Jan 2019

Studies On The Interaction And Organization Of Bacterial Proteins On Membranes, Mariana Brena

Masters Theses

Bacteria have developed various means of secreting proteins that can enter the host cell membrane. In this work I focus on two systems: cholesterol-dependent cytolysins and Type III Secretion.

Cholesterol is a molecule that is critical for physiological processes and cell membrane function. Not only can improper regulation lead to disease, but also the role cholesterol plays in cell function indicates it is an important molecule to understand. In response to this need, probes have been developed that detect cholesterol molecules in membranes. However, it has been recently shown that there is a need for probes that only respond to ...


Sex, Motivation, And Reversal Learning In The Common Marmoset (Callithrix Jacchus), Alyssa Carlotto Jan 2019

Sex, Motivation, And Reversal Learning In The Common Marmoset (Callithrix Jacchus), Alyssa Carlotto

Masters Theses

This study examined the relationships between motivation and cognitive performance in male and female common marmosets (Callithrix jacchus). This question was driven by prior data from the Lacreuse lab showing a robust female impairment in reversal learning, as assessed by the number of trials needed to acquire a reversal following a simple discrimination between two stimuli. This thesis tested the hypothesis that the female impairment in reversal learning was mediated by deficits in motivation. Two sets of measures were used to test this hypothesis. I evaluated physical effort via testing on the progressive ratio (PR), a test that requires animals ...


Mechanisms And Mitigation Of Skeletal Muscle Fatigue In Single Fibers From Older Adults, Aurora Foster Jan 2019

Mechanisms And Mitigation Of Skeletal Muscle Fatigue In Single Fibers From Older Adults, Aurora Foster

Masters Theses

Skeletal muscle fatigue is the contraction-induced decline in whole muscle force or power, and can be greater in older versus young adults. Fatigue primarily results from increased metabolism elevating phosphate (Pi) and hydrogen (H+), which alters myosin-actin interactions; however, which steps of the myosin-actin cross-bridge cycle are changed and their reversibility are unclear. PURPOSE: This study sought to: 1) Examine the effects of elevated Pi and H+ on molecular and cellular function, and 2) Test the ability of deoxyadenosine triphosphate (dATP), an alternative energy to adenosine triphosphate (ATP), to reverse the contractile changes induced with high Pi ...


Ecological Considerations And Application Of Urban Tree Selection In Massachusetts, Ashley Mcelhinney Jan 2019

Ecological Considerations And Application Of Urban Tree Selection In Massachusetts, Ashley Mcelhinney

Masters Theses

Trees provide countless environmental, economic, and societal benefits to the urban environment, and may become increasingly important to maintaining environmental quality and human well-being in the face of increasing urbanization and climate change. However, trees in these urban areas are rapidly diminishing across the United States. Much of this loss can be prevented with proper planning and management, focused on selecting tree species that are both well-suited to the area’s growing conditions and able to survive the many stress factors in an urban setting. Choosing which tree species to plant in Massachusetts is especially challenging considering the lack of ...


Development And Cross-Validation Of A Cadence-Based Metabolic Equation For Walking, Christopher C. Moore Jan 2019

Tropomyosin-Based Effects Of Acidosis On Thin-Filament Regulation During Muscle Fatigue, Brent Scott Jan 2019

Tropomyosin-Based Effects Of Acidosis On Thin-Filament Regulation During Muscle Fatigue, Brent Scott

Masters Theses

Skeletal muscle fatigue is defined as a loss in the force/velocity generating capacity of a muscle. A portion of the loss in function is attributable to effects of acidosis (i.e. low pH) on the regulatory proteins, troponin and tropomyosin (Tm), which regulate the binding of myosin and actin in a calcium (Ca++) dependent manner. However, the relative role of troponin and Tm on myosin-actin function during acidosis is not clear, nor are the mechanisms underlying these effects. PURPOSE: To determine the role of Tm in the acidosis-induced depression of muscle function using isolated muscle proteins in an in ...


Patterns Of Morphological Plasticity In Metriaclima Zebra And Danio Rerio Suggest Differently Canalized Phenotypes Due To Form-Function Relationships, Dylan Jockel Jan 2019

Patterns Of Morphological Plasticity In Metriaclima Zebra And Danio Rerio Suggest Differently Canalized Phenotypes Due To Form-Function Relationships, Dylan Jockel

Masters Theses

In order to ascertain the degree of compatibility in developmental restructuring and behavioral plasticity between two fish species frequently made subject of laboratory research (Metriaclima zebra & Danio rerio), alternative trophic niche exposure experiments utilizing novel three-prong feeding treatments were conducted to obtain morphometric data, which demonstrated both species do bear some degree of plasticity. The results are somewhat complicated by differences in locality of detectable restructuring, which may be due to disparity in the form-function relationship for each species’ lineage. Each is notable in the manner of respective species’ jaw protrusion, as it is driven by anterior kinethmoid rotation in ...


The Effects Of Acidosis On Calcium Dependent Binding Of A Single Crossbridge, Matthew Unger Jan 2019

The Effects Of Acidosis On Calcium Dependent Binding Of A Single Crossbridge, Matthew Unger

Masters Theses

Intracellular acidosis is a putative agent of skeletal muscle fatigue, in part, because acidosis depresses the calcium (Ca2+) sensitivity and force production of muscle (18, 50). However, the molecular mechanisms behind this depression in Ca2+ sensitivity and force production are unknown. This gap in knowledge poses a significant challenge in generating a complete understanding of the fatigue process. To close this gap, the ability of myosin to bind to a single actin filament was measured under acidic conditions, in a laser trap assay, with and without regulatory proteins. Decreasing pH from 7.4 to 6.5 reduced the ...