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D. Dwight Davis’s Legacy: A Morphological Examination of the Evolutionary Synthesis
No full textD. Dwight Davis was a morphologist who worked at the Field Museum of Natural
History in Chicago, publishing between 1932 and 1964. Best-known for an
authoritative monograph on the comparative anatomy of the giant panda, Davis
envisioned a field of morphology that could discern the evolutionary processes
leading to animal bodies. He searched for a broad alternative to the “Modern
Synthesis,” the unification of Darwinian evolution and genetics. Davis brought
together the neglected work of scientists like Richard Goldschmidt, D’Arcy
Thompson, and Conrad Waddington to fill in the missing links between small
genetic changes and large, relatively adaptive steps. While much of Davis’s
thought is unified in his work on the panda, his efforts in translating Phylogenetic
Systematics, which introduced cladistics to English-speaking evolutionists, stand
out. My argument is that Davis came to believe that the living history of actual
organisms was the most important factor in biological systems, and the new
approach of phylogenetics was an expression of the interplay of traits in the real
life of an organism. Biological progress is not the design of hypothetical
ancestors striving to become organisms that do not yet exist: the first insect, or
amphibian, or reptile, or mammal.Biological Science
Predicting Olivine Composition Using Raman Spectroscopy Through Band Shift and Multivariate Analyses
No full textOlivine minerals control many of the properties of Earth’s upper mantle. Additionally, olivines affect rheology, they may store hydrogen, and they are diagnostic of crystallization temperature. Olivine’s presence in meteorites and terrestrial bodies makes the study of this mineral group crucial to the planetary science community. Olivine composition can be characterized using Raman spectroscopy. This in situ technique will be used to characterize Martian minerals in upcoming missions such as ExoMars and Mars 2020.
Raman spectra of 93 olivines were acquired on Bruker’s 532 nm Senterra spectrometer. Of these samples, 25 were also run on Bruker’s BRAVO and Senterra (785 nm) spectrometers. Raman spectra of the olivine group minerals in the solid solution between forsterite (Mg2SiO4) and fayalite (Fe2SiO4) have a high intensity doublet between 800 and 880 cm-1. Historically, the band shift of these two peaks was utilized to predict the Mg/Fe contents (Kuebler et al., 2006; Foster et al., 2007; Gaisler and Kolesov, 2007; Mouri and Enami, 2008; Yasuzuka et al., 2009; Ishibashi et al., 2011), though these studies used different instruments and only limited data sets. This thesis compares the band shift method for understanding olivine composition with a more novel method using partial least squares (PLS), the least absolute shrinkage and selection operator (lasso), and least angle regression (LARS).
To evaluate the accuracy of each univariate model, both the R2 value of each fit (on a plot of composition versus peak centroid) and the cross-validated root mean squared error (RMSE-CV) of each model were used. Internal cross-validation of each data set was the most accurate %Fo predictor. For example, the model for which all data were acquired on the BRAVO spectrometer (under identical operating conditions) predicts %Fo content best for other data acquired on the BRAVO. For this reason, previous studies may appear deceptively accurate because they did not use cross-validation nor evaluate the accuracy of predictions on “unseen data” (data not included within the model).
Aggregated data sets from multiple instruments show excellent performance and can be generalized to other instruments for which calibrations are not available, such as the upcoming Raman Mars instruments. The most accurate %Fo predictions that avoid instrument bias result from an aggregated model produced through PLS or lasso multivariate analyses. A model that isolates the olivine doublet is also suggested instead of utilizing the entirety of the spectrum.
Overall, this thesis demonstrates that multivariate analyses are superior to univariate methods for prediction of olivine composition from Raman spectroscopy. Multivariate analyses that use multiple instrument data avoid instrument bias and leverage multiple aspects of the spectra. Recommended PLS and lasso models with the smallest errors are listed in the appendix of this thesis for the use of future workers.Astronom
Enacting Cosmopolitanism: Postcolonial Performances of 'European' Care for Asylum-Seekers in Reykjavík, Iceland
No full textThis thesis, based on the presenter’s fieldwork in Reykjavík, Iceland from May-July 2016, brings ethnographic evidence into conversation with anthropological scholars on humanitarianism, activism, migration, and cosmopolitanism. This work traces Iceland’s involvement with the 1951 UNHCR Convention and Protocol Relating to the Status of Refugees and the European Commission’s Dublin Regulation as, respectively, universalist and nationalist models for modern membership in a globally connected society. Specifically, this work examines the engagement of Laugarneskirkja (an Icelandic Lutheran church) with asylum-seekers as well as the activists and activisms of Andrými (the Icelandic chapter of No Borders International) as ways to understand a contemporary Icelandic interaction with displaced peoples as part of Iceland’s national cultural narrative.Sociology & Anthropolog
Empathy for the sake of Empathy: Examining the One-Shot Prisoner's Dilemma Game
No full textThe prisoner’s dilemma is a widely studied game within game theory.
It focuses on how we can elicit cooperation when there is a clear incentive to
defect. While this concept has been applied to a variety of situations, the
studies within game theory, and specifically about the prisoner’s dilemma,
lack research on true altruists (i.e., individuals who cooperate because they are
good people and not because there is an incentive to do so). The focus of this
paper is the distinction between empathetic people and narcissistic people and
presents a model that shows how true altruists can remain in society despite
narcissists constantly taking advantage of them. The model considers a oneshot
Bayesian prisoner’s dilemma game. The one-shot nature of the game is
used to simulate a lack of reciprocity and, therefore, represents individuals
that cooperate because of who they are as opposed to other incentives. The
Bayesian model allows for the distinction between empathetic and narcissistic
individuals. The results from this model suggest that empathetic individuals
can remain in society as long as there are enough empathetic individuals (µ)
and enough of the “warm feeling” (ε) that these individuals receive from
being altruistic and cooperating. Further work on this model can include
endogenizing both ε and µ as well as studying the relationship within actual
populations.Economic
IDENTIFICATION OF A DEGRADATION SIGNAL IN THE ANTI-SIGMA FACTOR CSFB REQUIRED FOR THE SWITCH TO LATE GENE EXPRESSION DURING BACILLUS SUBTILIS SPORULATION
No full textIn response to adverse environmental conditions, the gram-positive bacterium Bacillus subtilis undergoes an adaptive process known as sporulation, culminating in the production of a metabolically dormant, extraordinarily resistant cell type called a spore. Sporulation is tightly regulated by alternating early and late sigma factors, which direct the expression of developmental genes. The anti-sigma factor CsfB plays an important role in the σF to σG switch in the developing spore by inhibiting σG at early times while σF must be active. Unpublished work from the Camp laboratory revealed that unlike GFP alone, a GFP-CsfB fusion protein degraded quickly during sporulation. Moreover, this degradation is known to depend, at least partially, upon the protease ClpCP. To identify the signal sequence on CsfB that allows for its recognition by the protease, I constructed GFP-CsfB fusion protein variants either harboring or lacking parts of the CsfB C-terminus. B. subtilis strains expressing these constructs were screened for changes to protein levels during sporulation by both western blot and fluorescence microscopy. My data revealed that the last 3 residues (LYS) are sufficient but not necessary for degradation. Further inspection of various GFP-CsfB variants shows the presence of a second internal degron that is also sufficient but not necessary for degradation. Next, I attempted to construct a variant of GFP-CsfB that lacked both degrons but retains its ability to inhibit σG. Finally, I tested the dependence of each degron upon the ClpCP protease by knocking out the clpC gene and observing the degradation pattern of various GFP-CsfB variants. Data indicated that degradation via the C-terminal degron and the internal degron both depend upon the ClpCP protease. These results will help elucidate the importance of proper CsfB degradation during σG regulation, and more broadly, proper cell differentiation in Bacillus subtilis sporulation.Biological Science
Cuba's Unresolved UMAP History: Survivors' Struggles to Counter the Official Story
No full textThe History department thesis “Cuba’s Unresolved UMAP History: Survivors’ Struggles to Counter the Official Story” explores how the Castro regime and its victims remember the island’s reeducation camps. The Military Units to Aid Production (UMAP) camps were created in 1964 and constructed throughout the province of Camagüey. Applicants for Cuban passports, gays, political dissidents, and religious minorities were detained and forced to work for below minimum wages to cultivate agricultural fields. The great majority of laborers worked in sugarcane fields to boost production. Prisoners were not only exposed to hard labor but also physical and emotional abuses. The Cuban Union of Writers and Artists led protests against the camps and managed to spread information about these human rights atrocities outside of Cuba, including hormonal experimentation on gay laborers. The level of negative press that these reeducation camps earned outside of the island prompted Fidel Castro to close and demolish them by 1969.
Research funded by an Almara fellowship involved survivors’ published and unpublished testimonies, an interview with the leader of a survivors’ organization, and various print sources dealing with the camps during the 1960s and their controversies later. Castro’s targeting of deviant labor led his regime on multiple occasions to reframe the image and stories surrounding these camps that were never officially commemorated by the state. While the official justification originally claimed the camps provided marginalized civilians the opportunity to reform themselves and contribute economically to Cuba, some victims of the UMAP camps saw themselves instead as the slaves of a regime that discriminated against them and disregarded their rights while exploiting their labor. The camps served as a stepping-stone towards the Ten Million Ton Harvest effort of 1970 that redefined the ideal patriotic man through the New Man campaign. The swift transition from the UMAP camps to these subsequent campaigns allowed for Cuban society to focus on its future rather than commemorate its past.Histor
Hoaxes, Memes & Bots
No full textIn 2016 the world woke up to the severity of the polluted information environment. This lecture explained why we need to consider the whole spectrum of the misinformation ecosystem, what we learned from monitoring disinformation in the French, UK, and German elections, and why we have to stop using the term “fake news.” Most importantly, it included practical tips so you can make sure you don't get fooled by the hoaxes, misattributed, and manipulated content that surfaces online. Nic Dias is a senior research fellow at First Draft News, a nonprofit dedicated to supporting truth and trust on the internet. He has a background in computational journalism and social science. Nic's recent research interests include the use of bots to boost hyperpartisan perspectives, misinformation and disinformation on social media. In this avenue, he has studied the use of social bots to amplify misinformation in the United States, France, the United Kingdom and Germany -- particularly during elections. Other curiosities of his include the psychological principles dictating the correction of false beliefs
The role of Aur-A in Drosophila melanogaster fat body remodeling
No full textTissue remodeling is an important process in multicellular organisms that
is necessary for processes such as wound healing and tumor metastasis. For
remodeling to occur, connective proteins of the extracellular matrix (ECM) must
be cleaved so that cells can migrate. The migration of cells in wound healing
promotes wound closure and ECM degradation allows cancerous cells to separate
from the tumor to metastasize.
Drosophila melanogaster undergoes metamorphosis from larva to adult.
Most larval tissues undergo apoptosis, but the larval fat body undergoes
remodeling and persists until after the adult has eclosed. During remodeling, the
larval fat body cells change from being polygonal cells connected in sheets to
spherical cells that are free floating. Since D. melanogaster possess multiple tools
for genetic analysis, this organism is a commonly used model organism in
biomedical research.
Drosophila were fed EMS to establish mutations on their third
chromosome and were then scored for lethality. Twenty of these lines are pharate
adult lethal, wherein the newly formed adult flies fail to eclose from their pupal
case, and have larval fat body remodeling abnormalities. The fat body phenotype
was screened and categorized according to the level of remodeling. The
chromosomal location of four of the mutated genes that cause pharate adult
lethality and abnormal fat body remodeling was attempted to be established.
Three of the mutated lines were determined to have mutations in the aur-A
gene. This gene is known to affect the cytoskeleton arrangement in neuroblasts,
but its role in fat body remodeling is unknown. The results from this study
suggest that that this mutated gene does affect the actin filament organization.Biochemistr
Education, Equity, and Experience
No full textIn recent years, youth entrepreneurship has become a trending topic amongst colleges and universities across the United States. At Harvard’s Graduate School of Education in the Leadership Lab Initiative this summer, I examined the causes of the uptick in youth entrepreneurship and how universities are supporting young entrepreneurs pursuing their college degrees. Our lab discovered that college students today are more likely to pursue entrepreneurship over traditional careers because of their desire to make a difference and their fear of another economic recession that could potentially leave them jobless after years of service at a particular company or corporation. As part of the research, I interviewed 73 student entrepreneurs, professors of entrepreneurship courses, and directors of centers for entrepreneurship at 43 of the top 50 universities known for their entrepreneurship programs. We found two major results. First, we discovered that there is a generation of young founders emerging, due in part to what many call the “Facebook effect,” that we are calling Generation F. Second, entrepreneurship is being taught using the lean startup method and advanced experiential learning and we are calling that style of teaching the Creation-Based Learning Model. We discovered that interest in entrepreneurship is rising immensely, but the number of students pursuing entrepreneurship post-graduation is still relatively small, perhaps in part due to the risk factors involved in starting a business. Despite this, many of those interviewed mentioned that the barriers of entry for entrepreneurs have never been lower. This presentation will focus on the role of experiential learning and educational supports available for student entrepreneurs at colleges and universities across the country, as well as discuss in depth what defines a member of Generation F and the pedagogy surrounding the Creation-Based Learning Model.Educational experiences differ vastly from person to person based on a multitude of factors. When thinking about and addressing these features, it is crucial to consider the role of education inequity. From one’s physical location to differences in learning style, these panelists spent their summers investigating factors that influence education, as well as what can be done to work towards education equity. While working at various labs throughout the east coast, three of the panelists were able to look at the educational experiences across many age groups, from students in early childhood and elementary school classrooms to those attending graduate school. One panelist worked at an education-based nonprofit where she focused on event planning, while also learning the positive effects of providing long-term education intervention. As education is regarded highly, educators need to be cognizant of factors that influence the education their students are receiving and what can be done to provide all students with the best education possible
Parental Boundary Dissolution and Young Adults’ Romantic Relationships
No full textParental boundary dissolution is a term used to describe a parent-child relationship structure wherein a parent breaches age-appropriate and relationship-appropriate boundaries with their child. The current study aimed to examine the association of boundary dissolution with negative indicators of sexual and romantic relationship health in young adulthood, the moderating role of family risk factors and other indicators of parent-child relationship quality, as well as the mediating role of emotion regulation between boundary dissolution and negative sexual and romantic relationship outcomes. Results did not support hypotheses. However, emotion regulation emerged as a significant correlate of sexual and relationship health, as were race and household income. The findings demonstrate that self-report measures may not be adequate measurements of boundary dissolution and that more research needs to be done to address cultural differences in family structure.Psychology & Educatio