Effects of the Invasive Asian Shore Crab, Hemigrapsus sanguineus, on New England Trophic Cascade: Diet and Predation

Trophic cascades occur when the community structure is influenced by indirect effects of predation on the lower trophic levels. The trophic cascade can be disrupted when an invasive species is introduced. The Asian shore crab, Hemigrapsus sanguineus has invaded ecosystems in New England and we predict this invasion will negatively affect the classic New England trophic cascade. By the predation indirectly affecting lower trophic levels, H. sanguineus can influence the community structure and diversity at the lower levels. To understand the trophic cascade, we manipulated the food source and competitors in four different mini-ecosystems. By introducing H. sanguineus into an environment with L. littorea and two algal species; Fucus distichus and Ulva sp., we confirmed that H. sanguineus disrupts the trophic cascade. Specifically, the Asian shore crab, consumed the snail’s preferred type of algae, which led to the indirect effect on the trophic cascade. The findings of this experiment confirmed that with the presence of the invasive crab, the Asian shore crabs had an indirect effect on the snail. Invasive species can have a negative effect on trophic cascades resulting from competitive exclusion

Girl Crush: Liminal Identities and Lesbian Love in Children\u27s Cartoons

A textual analysis of the cartoon Steven Universe, this project takes a semiotic approach to explore anti-essentialist messages of gender identity. I argue that within the mainstream media, the cartoon expresses prosocial messages about gender by representing nonbinary characters and gender fluid themes. Using children’s media studies, queer studies, and reception studies, I investigate how the show portrays liminal identities. In particular, I focus on how lesbian existence and gender fluidity are simultaneously normalized and othered through the text’s visuals and dialogue. Critically analyzing the ways in which the media represents queerness as ‘too adult,’ this study reveals that children’s programming can constructively depict queer identities in a media landscape that otherwise often distances children from queerness. By contextualizing the history of cartoon production, queer representation, and audience reception, my analysis provides insight into the importance of prosocial depictions of gender identity in children’s media

Ironing Out Anemia: Assessing the Role of Marketplace Factors and Government Investment Incentives in Shaping East African Pharmaceutical Markets

Africa suffers from the highest disease burden in the world, with over half of the population lacking regular access to essential medicines (Owoeye, 2014, p.214; Chaudhuri & West, 2015, p.23). Following two decades of reform, the continent has now emerged one of the fastest-growing economic regions, shifting public health focus toward non-communicable diseases (NCDs) (Holt et al., 2015, p.2). Among these NCDs is anemia, which has direct and indirect economic effects as large as 4.05% of GDP (Horton & Ross, 2003, p.51). Encouraged by the rapid growth of liberalized markets, African governments and health officials are now considering local pharmaceutical production as a way to unlock the economic, social, and political benefits of improved public health. This thesis explores two hypotheses: (a) tax incentives effectively induce greater foreign direct investment in East Africa, including pharmaceutical production, and (b) local pharmaceutical production in East Africa provides better access to essential medicines like haematinics (anti-anemia drugs) as measured by anemia prevalence in children under five. We study these questions using Ethiopia and Rwanda as representative countries. Taking effect in 2012, Ethiopia’s Double Taxation Avoidance Agreement (DTAA) with India created local investment incentives via low tax rates as compared to Rwanda, which has no such agreement. We perform a difference-in-differences (DID) regression using data from Demographic and Health Surveys (DHS) to estimate the causal relationship between favorable investment conditions and anemia rates among children. Our results are inconclusive and suggest determinants of anemia are numerous and interconnected

Temperature dependent refractive index of silicon and germanium

Silicon and germanium are perhaps the two most well-understood semiconductor materials in the context of solid state device technologies and more recently micromachining and nanotechnology. Meanwhile, these two materials are also important in the field of infrared lens design. Optical instruments designed for the wavelength range where these two materials are transmissive achieve best performance when cooled to cryogenic temperatures to enhance signal from the scene over instrument background radiation. In order to enable high quality lens designs using silicon and germanium at cryogenic temperatures, we have measured the absolute refractive index of multiple prisms of these two materials using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA Goddard Space Flight Center, as a function of both wavelength and temperature. For silicon, we report absolute refractive index and thermo-optic coefficient (dn/dT) at temperatures ranging from 20 to 300 K at wavelengths from 1.1 to 5.6 microns, while for germanium, we cover temperatures ranging from 20 to 300 K and wavelengths from 1.9 to 5.5 microns. We compare our measurements with others in the literature and provide temperature-dependent Sellmeier coefficients based on our data to allow accurate interpolation of index to other wavelengths and temperatures. Citing the wide variety of values for the refractive indices of these two materials found in the literature, we reiterate the importance of measuring the refractive index of a sample from the same batch of raw material from which final optical components are cut when absolute accuracy greater than +/-5 x 10^-3 is desired.Comment: 10 pages, 8 figures, to be published in the Proc. of SPIE 6273 (Orlando

Temperature-dependent Refractive Index of CaF2 and Infrasil 301

In order to enable high quality lens designs using calcium fluoride (CaF2) and Heraeus Infrasil 301 (Infrasil) for cryogenic operating temperatures, we have measured the absolute refractive index of these two materials as a function of both wavelength and temperature using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center. For CaF2, we report absolute refractive index and thermo-optic coefficient (dn/dT) at temperatures ranging from 25 to 300 K at wavelengths from 0.4 to 5.6 pm, while for Infrasil, we cover temperatures ranging from 35 to 300 K and wavelengths from 0.4 to 3.6 pm. For CaF2, we compare our index measurements to measurements of other investigators. For Infrasil, we compare our measurements to the mate~al manufacturer's data at room temperature and to cryogenic measurements for fused silica from previous investigations including one of our own. Finally, we provide temperature-dependent Sellmeier coefficients based on our measured data to allow accurate interpolation of index to other wavelengths and temperatures

Cryogenic Temperature-dependent Refractive Index Measurements of N-BK7, BaLKN3, and SF15 for NOTES PDI

In order to enable high quality lens designs using N-BK7, BaLKN3, and SF15 at cryogenic temperatures, we have measured the absolute refractive index of prisms of these three materials using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, as a function of both wavelength and temperature. For N-BK7, we report absolute refractive index and thermo-optic coefficient (dn/dT) at temperatures ranging from 50 to 300 K at wavelengths from 0.45 to 2.7 micrometers; for BaLKN3 we cover temperatures ranging from 40 to 300 K and wavelengths from 0.4 to 2.6 micrometers; for SF15 we cover temperatures ranging from 50 to 300 K and wavelengths from 0.45 to 2.6 micrometers. We compare our measurements with others in the literature and provide temperature-dependent Sellmeier coefficients based on our data to allow accurate interpolation of index to other wavelengths and temperatures. While we generally find good agreement (plus or minus 2 x 10(exp -4) for N-BK7, less than 1 x 10(exp -4) for the other materials) at room temperature between our measured values and those provided by the vendor, there is some variation between the datasheets provided with the prisms we measured and the catalog values published by the vendor. This underlines the importance of measuring the absolute refractive index of the material when precise knowledge of the refractive index is required

Effect of an impulsive force on vortices in a rotating Bose-Einstein condensate

The effects of a sudden increase and decrease of the interatomic interaction and harmonic-oscillator trapping potential on vortices in a quasi two-dimensional rotating Bose-Einstein condensate are investigated using the mean-field Gross-Pitaevskii equation. Upon increasing the strength of interaction suddenly the condensate enters a nonstationary oscillating phase which starts to develop more vortices. The opposite happens if the strength is reduced suddenly. Eventually, the number of vortices attains a final value at large times. Similarly, the number of vortices increases (decreases) upon a sudden reduction (augmentation) in the trapping potential. We also study the decay of vortices when the rotation of the condensate is suddenly stopped. Upon a free expansion of a rotating BEC with vortices the radius of the vortex core increases more rapidly than the radius of the condensate. This makes the counting and detection of multiple vortex easier after a free expansion.Comment: RevTeX 4, 7 pages, 7 EPS figure

Choreographic and Somatic Approaches for the Development of Expressive Robotic Systems

As robotic systems are moved out of factory work cells into human-facing environments questions of choreography become central to their design, placement, and application. With a human viewer or counterpart present, a system will automatically be interpreted within context, style of movement, and form factor by human beings as animate elements of their environment. The interpretation by this human counterpart is critical to the success of the system's integration: knobs on the system need to make sense to a human counterpart; an artificial agent should have a way of notifying a human counterpart of a change in system state, possibly through motion profiles; and the motion of a human counterpart may have important contextual clues for task completion. Thus, professional choreographers, dance practitioners, and movement analysts are critical to research in robotics. They have design methods for movement that align with human audience perception, can identify simplified features of movement for human-robot interaction goals, and have detailed knowledge of the capacity of human movement. This article provides approaches employed by one research lab, specific impacts on technical and artistic projects within, and principles that may guide future such work. The background section reports on choreography, somatic perspectives, improvisation, the Laban/Bartenieff Movement System, and robotics. From this context methods including embodied exercises, writing prompts, and community building activities have been developed to facilitate interdisciplinary research. The results of this work is presented as an overview of a smattering of projects in areas like high-level motion planning, software development for rapid prototyping of movement, artistic output, and user studies that help understand how people interpret movement. Finally, guiding principles for other groups to adopt are posited.Comment: Under review at MDPI Arts Special Issue "The Machine as Artist (for the 21st Century)" http://www.mdpi.com/journal/arts/special_issues/Machine_Artis

Dissipative dynamics of vortex arrays in trapped Bose-condensed gases: neutron stars physics on μ\muK scale

We develop a theory of dissipative dynamics of large vortex arrays in trapped Bose-condensed gases. We show that in a static trap the interaction of the vortex array with thermal excitations leads to a non-exponential decay of the vortex structure, and the characteristic lifetime depends on the initial density of vortices. Drawing an analogy with physics of pulsar glitches, we propose an experiment which employs the heating of the thermal cloud in the course of the decay of the vortex array as a tool for a non-destructive study of the vortex dynamics.Comment: 4 pages, revtex; revised versio

A Comparative Test of Creative Thinking in Preschool Children and Dolphins

Creativity is considered one aspect of intelligence. Including creativity allows for more room for expression (e.g., participants can respond with movement instead of written or verbal responses) than in standard intelligence assessments. The Torrance Tests of Creative Thinking (TTCT; Torrance, 1974) are the leading method of assessing creative abilities in school-aged humans and above. To assess creativity in young humans and nonhuman animals, modifications must be made to facilitate nonverbal responses. In the current study, a cross-species comparison was conducted between preschoolers and bottlenose dolphins to examine responses to a modified creativity task in which both species were trained to demonstrate non-repeated behaviors to an “innovate” prompt. The resulting behaviors for the first test session were coded for fluency (number of non-repeated behaviors demonstrated), originality, and flexibility (low, moderate, or high activity level). Children and dolphins produced a similar number of non-repeated behaviors during individual test trials and also had similar originality scores. Related to flexibility, dolphins displayed more low energy activity levels compared to the children. Given the limited understanding of creative abilities in animals and young children, this comparison using a modified version of the TTCT offers exciting possibilities. These results could provide further evidence of similarities in cognitive processes for humans and nonhuman animals