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Modeling Age Structure, Abundance, and Distribution of Maple Species on Campus
No full textNorway maple (Acer platanoides), one of the most abundant invasive trees in
Massachusetts, is often associated with reduced native forest diversity. To shed
light on the effects of Norway maple on sugar maple (Acer saccharum) and red
maple (Acer rubrum) - local native maple species - I conducted a study on the
Mount Holyoke campus. In three sites, I recorded tree species and diameter,
average canopy cover, and soil moisture. With multivariate regression, I analyzed
relationships between abiotic variables and maple species and any interaction
effects among maple species. To explore the population and community
consequences of small changes in survival and growth, I attempted to construct
population projection matrix models for each maple species.
Environmental conditions appear to affect recruitment and growth of each
maple species with the most overlap in sugar and red maples. The size
distributions suggest that red maple may originally have been dominant but is
experiencing replacement by sugar maple. Although both sugar and Norway
maples are increasing, there are indications that Norway maple may negatively
affect sugar maples and could replace it in the long term.
Long-term data are highly desirable for matrix models to confirm the interaction and replacement
dynamics among the maple species.Biological Science
The Role of desat1 in Courtship and Pheromone Synthesis of Male and Female Drosophila Melanogaster
No full textSexual reproduction has fascinated scientists for centuries. The analysis of animal sexual behavior in other animals has helped to enlighten us about human sexual behavior 1. However, it has been argued that our mating habits are not controlled by pure biological need. Some have stated that due to our higher order of thinking, we can override the base biological need to choose a mate based on pheromones. However, through studying model organisms, such as Drosophila melanogaster, we have learned that pheromones play a larger role in mate choice than was previously thought2.
In this project, Drosophila melanogaster is used to study the role of pheromones in courtship. Drosophila males perform an intricate courtship dance that is primarily controlled through the pheromones that males and females emit. However, there are several mutations that affect the pheromones and how they are interpreted by Drosophila. A mutation of interest is desat1. desat1 is a mutation that affects male Drosophila. desat1 mutants lack desat1 desaturase. desat1 desaturase promotes desaturation of the fatty acids that contribute to the courtship stimulatory pheromones. Without desat1 desaturase, very few correct courtship stimulatory pheromones are produced. Beyond desat1 mutant’s tendency to mate quickly, not much is understood about the effects the lack of courtship stimulatory pheromones have on other flies3.
Courtship assay between a desat1 male, desat1 female, and a wild-type female have been described4. If a desat1 male ispresented with both desat1 and wildtype females, the male will almost always choose the desat1 female. This phenomenon has not been widely studied and is the focus of my experiments. Published observations indicate that desat1 mutant females behave like wild-type females. When desat1 females are presented with wild-type males, their courtship behavior is identical to that of the wild-type/wild-type pairings. However, no research has been done on whether or not there is a difference in the pheromones desat1 females and wild-type females are emitting3. It is possible that they are emitting a pheromone that, under normal conditions, has no effect on mating but when this pheromone is encountered by the desat1 mutant, it overrides anything it sense from the wild-type female 4. In this project, I studied the courtship assays of desat1 males and females to learn how the mutation has the mutation has affected their sexual competence. I have also analyzed their pheromone profiles, using GC-mass spectroscopy to further elucidate my finding from the courtship assays.Biochemistr
Ultrasonic Backscatter Coefficients, Attenuation Coefficients, and Speed of Sound Measurements on Human Colon Carcinoma Cells
No full textMeasuring and analyzing the ultrasonic properties of cancer cells in vitro may
identify specific properties of these cells leading to better ultrasound diagnostics. We
aim to quantify human colon carcinoma cells through ultrasonic measurements of speed
of sound, attenuation coefficients and backscatter coefficients at various frequencies.
Measurements were made using single element transducers at frequencies of 5-25MHz
in a controlled water-tank environment. Human Colon Carcinoma cells (HCT) were
cultured and a pellet made using 1% agar solution. The attenuation, speed of sound and
backscatter coefficients were then measured in order to determine quantitative
information. For the speed of sound and attenuation experiments, the sample was
placed between a transmitting transducer, connected to an amplifier and a function
generator, and a receiving transducer connected to an oscilloscope. The amplitude of
the wave and the delay time of the pulse were recorded with and without the sample
compared to the water only path. The attenuation coefficients and the speed of sound
were calculated based on changes in time and wave amplitude due to the presence of
the sample. A backscatter experiment from 5-25MHz using a single element focused
transducer was also performed. The transducer was connected to a pulser receiver and
the output of the pulser receiver connected to an oscilloscope that displayed the
transmission of the signal. When the sample was aligned with the transducer, a signal
was recorded and the coefficient calculated using Matlab. We are currently working to
improve the speed of sound, attenuation, and backscatter data obtained in order to
quantify the tissue characteristics of HCT cells. Future directions would include
comparing data obtained for HCT cells with other cancer cells as well as against normal
human colon cell lines.Biochemistr
The Perceived Motivating Power of Exercise-related Social Media Varies as a Function of Social Media Platform and Account Type
No full textThe present research set out to determine the extent to which people perceive exercise-related content on different social media platforms (Twitter or Instagram) or from different types of users (individuals or corporations) to motivate themselves and others to exercise. Two studies employed an explanatory sequential design, in which a quantitative study was followed by a qualitative study. Participants rated motivational characteristics of 40 exercise-related social media stimuli and completed measures of their motivation to exercise, current exercise habits, and related measures. Ten people subsequently participated in one of three focus groups to discuss perceptions of exercise-related social media. Several hypotheses regarding differences in perceptions of different types of social media (Twitter vs. Instagram; individual vs. corporate) were tested. Instagram stimuli were rated as more motivational than Twitter stimuli for self-reported motivation, whereas account type was found to play a role in predicting motivation only when platform was also taken into consideration. Positive bivariate correlations were also found between the degree to which a participant was autonomously motivated to exercise and how much the Corporate stimuli motivated them to exercise. A thematic analysis of the focus groups identified three primary themes: finding enjoyment in the obligation of exercising, motivation from others, and social media’s impact on perceiving others. Overall, the motivational impact of social media is influenced by which platform it is on and who is posting it.Psychology & Educatio
Painting Interiors: An Excavation of the Subterranean World
No full textAs an artist, I have a responsibility to dream. These dreams are often made up of fragments of my life experiences and observations. The ordinary scenes I experience daily, give rise to escapism that help soothe the rigid reality. My paintings depict my process of constructing a world we can not see. In the excavation of these subterranean environments, I imagine that when reality is dismantled, a space where our subconscious dwells is revealed.
Interior spaces are sanctuaries for the restless mind. They stimulate the preciousness of a space through its storing capability and sheltering quality. Their willingness to be domesticated and personalized enables memories and emotions to exist. These spaces are the main motif and starting points of my work. Basing the interior architecture on real spaces I have encountered, I am able to mimic the sensation of lingering over banal objects in my paintings. This immersion into a virtual space permits an endless amount of possibilities bounded by the limits of oil paints. The interior rooms that were once confined by the pressures of reality, are thus liberated and transformed into spaces that harbor the subliminal thoughts of nostalgia and solitude.
By closely observing the present reality and my past history, I have unearthed alluring resolutions that piece together images of a hidden world. By processing through layers of paint, my spaces are able to reach a level of transcendence that exist between reality and fiction. As a result, the creation of this amalgamated world challenged my understandings of architecture, time, and identity.Art Studi
Synthesis and Characterization of Decanoic Acid Coated Magnetic Iron (III) Oxide Nanocubes for the Preparation of Uniform Nanocube Monolayers
No full textWhile research into the synthesis and characterization of magnetic iron oxide nanospheres has been heavy, the study of different shapes of iron oxide, such as nanotubes, nanocubes, nanorods, etc. has not been thorough. In this project, we investigated the less common magnetic Fe3O4 nanocubes. These nanocubes were synthesized by the thermal decomposition of iron (III) acetylacetonate. The synthesis was carried out in the presence of decanoic acid as the surfactant and also the organic solvent dibenzyl ether. The presence of decanoic acid coated nanocubes were confirmed using Fourier Transform Infra-red (FTIR) Spectroscopy.
Since iron oxide nanocubes are unstable in air and especially in solution, due to their high surface energy and tendency to aggregate, mixed solvent systems of different ratios by volume of chloroform to methanol namely, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1 were used as dispersing agents for the nanocubes with pure chloroform as a control. This was done to determine if mixed solvent systems would be able to prevent the formation of nanocube aggregates as opposed to single solvent systems.
The decanoic acid coated nanocubes were analyzed under a Transmission Electron Microscope (TEM) which were deposited on carbon-coated TEM grids. These particles were deposited on the grids using two different techniques, the Langmuir-Schaefer technique at the air-water interface, as well as drop casting. Slope analysis of the isotherms obtained from Langmuir-Schaefer samples were performed to study phase transitions during sample preparation. The TEM grids for different samples were analyzed under the microscope to record images in order to study the behavior and morphology of the nanocubes. TEM analysis revealed that thin, crystalline packing of nanocubes could be achieved when the Langmuir-Schaefer technique was used with a chloroform:methanol ratio of 3:1. The size distribution of the nanocubes could be measured from TEM images and a pure chloroform sample was used to determine the average size to be 14.25 ± 4.04 nm which is quite close to the superparamagnetic limit of iron. From the results it could be confirmed that a mixed solvent system of chloroform and methanol is able to disperse decanoic acid coated nanocubes to reduce aggregation in solution and for the formation of crystalline packed layers and that thermal decomposition is a suitable method to synthesize uniform nanocubes with a narrow size distribution.Chemistr
Power and Property in the Community Forests of Bhutan
No full textPower and property are mutually constituted and continually (re)negotiated and inextricable throughout the world, including in the eastern Himalayan Kingdom of Bhutan. Forest governance and access to natural resources are two arenas in which these power relations play out. Through community forestry, the Royal Government of Bhutan has decentralized, but not devolved, power over the resources that people depend on for livelihoods, subsistence, and survival. The government does this by prioritizing certain forms of land use (primarily biodiversity conservation), controlling infrastructure development, and maintaining ownership rights over forests. I argue that the government should devolve power through ownership rights and increased decision-making control for local communities because this could address several social, economic, and ecological problems that the country is facing, including rural - urban migration and youth unemployment.
During the fall of 2015, I studied abroad with the School for Field Studies (SFS) program ‘Himalayan Environment and Society in Transition.’ I interviewed people in three villages in the district of Bumthang about rights and access to the natural resources in community forests. I compared my results to the language that the government uses about land and community forestry in official documents, finding a lack of devolution of power over resources.
Throughout the past 60 years, forest governance and property laws have changed several times. In 1969, the National Assembly passed the Forest Act, nationalizing all forests that were not in private hands. In 1996, the National Assembly passed the Forest and Nature Conservation Act, creating a system of community forestry in which the government decentralized decision-making to local officials but did not devolve the power to make decisions about those resources to the resource users. Devolution of power over resources, within a capitalist mode of production, provides people with the means of achieving not only subsistence and survival, but long-term security as well.
When land is expropriated, people lose control over their means of survival; this expropriation is necessary in a capitalist system to create wage laborers. Having access to land and resources is one way to disentangle oneself from the exploitation of labor. At the same time that Bhutan’s economy is developing capitalist characteristics, the government maintains a rhetorical commitment to Gross National Happiness and a recognition of traditional culturally and ecologically sustainable ways of living that are assumed to have existed in Bhutan throughout its history.
If the Bhutanese government is to honor its commitments to preserve the country’s biodiversity and cultural history, it must continue its path to devolution of power over land and natural resources, which form the bedrock of Bhutanese livelihoods, subsistence, and survival. Government officials have made substantial progress in terms of decentralization, but to address the rapid modernization and capitalist changes that are occurring in the economy, political system, and culture, they must remain aware of what is best for Bhutan’s citizens, regardless of pressures from abroad.Environmental Studie
Isoform-Specific Effects of the DOA Kinase on Autophagic Cell Death of the Larval Salivary Glands in Drosophila melanogaster
No full textFamilies of protein kinases have been conserved over millions of years,
and they play important roles in many cellular processes such as the cell cycle,
differentiation, and signal transduction (Neiman, 1993). Doa, or Darkener of
apricot, is a locus found in Drosophila melanogaster that encodes a protein
kinase belonging to the LAMMER kinase family. There are seven known protein
isoforms of the DOA kinase, which differ by molecular weight and developmental
specificity (Kpebe and Rabinow, 2008). While the isoforms contain identical Cterminal
catalytic domains, the N-terminal noncatalytic domains are different due
to the use of alternative promoters (Kpebe and Rabinow, 2008). Given the number
of different structures of DOA isoforms and their respective developmental
specificity, it is possible that the isoforms are performing different molecular
functions (Kpebe and Rabinow, 2008).
Macroautophagy, referred to here as autophagy, is a crucial process that
aids in the regulation of cellular homeostasis (Lockshin and Zakeri, 2004).
Autophagy is lysosomally-mediated, and is an important process involved in the
removal and degradation of bulk cytoplasm and long-lived proteins and organelles
(Berry and Baehrecke, 2007). The salivary glands in Drosophila melanogaster
offer an ideal model for studying developmental autophagic cell death in vivo,
since the bulk of the cytoplasm in the larval salivary glands are removed via
autophagic cell death during metamorphosis (Lockshin and Zakeri, 2004).
In this project, interfering RNA (RNAi) constructs encoding short hairpin
RNAs (shRNAs) were used to silence the expression of specific Doa isoforms
through the degradation of homologous mRNA. The constructs each target a
different Doa isoform mRNA, because the N-termini are all different from one
another, and are being expressed from alternative promoters. This approach could
hypothetically reveal different functions of the Doa isoforms. The segregation of
markers (Tb on the balancer chromosome TM6 or TSTL) is used to follow
genotypes of overexpression/RNAi for Doa.
Since RNAi in Drosophila is cell-autonomous, the GAL4-UAS system can
be used to target the expression of the RNAi constructs. By crossing female flies
with a UAS-GFP responder to males with a Salivary Gland (SG) GAL4 driver, it
is possible to express GFP in the salivary glands of the progeny. The salivary
glands can be visualized via fluorescence microscopy, and images taken at 6 hour
intervals should reveal a construct’s effects on autophagic cell death. Differences
in levels of autophagy of the salivary glands between flies with the modifier
construct and the wild-type could be indicative of an isoform’s involvement in the
promotion or inhibition of cell death.Biological Science
The meaning of symbolism in tattoos: A qualitative inquiry into the relationship between individuals and their body art
No full textThis study investigated the nature of the relationships between individuals and their own tattoo(s). Through considering the personal construction of symbolic meaning involved with getting and having a tattoo, this research addressed how tattoos serve a performative, significant function for the individuals who wear them. Specifically, attention was paid to how tattoos and their capacity for constructed symbolism play an important, long-term role in how individuals are connected to themselves and/or to the greater world. To address this question, semi-structured in-person interviews were conducted with eight individuals with one or more tattoo(s). Data were analyzed in a qualitative manner, specifically using the method of inductive thematic analysis. This study was ideographic in nature, as this topic had not previously been explored, nor have previous studies utilized qualitative methodology as a means of research for this subject.Psychology & Educatio
Where are the Unmarried Women? The Impact of Truth Commissions on Post-Conflict Gender Relations
No full textA recent trend in the field of transitional justice has been the inclusion of a gendered perspective to ensure that women’s experiences during war are addressed effectively. For truth commissions in particular, this has meant implementing various gender-sensitive protocols such as women- only hearings for victims to testify about experiences of sexual violence, as well as chapters in final reports dedicated to the experiences of women during conflict. The Sierra Leone Truth and Reconciliation Commission (TRC) is considered to be a successful example of how to address the needs and experiences of women. Yet despite a number of comprehensive recommendations and extensive research into the pre-existing social inequalities that contributed to the wartime experiences of Sierra Leonean women, progress towards gender equality since the commission has been slow. My research explores how the almost singular portrayal of Sierra Leonean women as passive victims of sexual violence has reproduced previous notions of gender roles, and in turn hindered progress. By tracing legal trends and narratives of womanhood in popular Sierra Leonean culture, I assess the impact that the TRC has had on the lives of women, and identify missed opportunities. I draw larger connections through an analysis of five other truth commissions from around the world: Liberia, Ghana, Peru, East Timor, and Guatemala. I argue that in order for truth commissions to have a lasting impact on women’s lives post-conflict, their reports must include more diverse narratives of women’s experiences of war—narratives that go beyond a singular portrayal of women as victims of sexual violence. This thesis contributes to the existing literature on transitional justice by demonstrating the damaging impact of these essentialized narratives.Politic