Graduate students of color: the impact of mentoring at predominantly white institutions

2019 Summer.Includes bibliographical references.Despite the increasing diversity of the US population, particularly of Latinx residents, the lack of resources and the underrepresentation of graduate students of color (GSC) are lingering issues in higher education. This dissertation discusses the impact of mentoring at predominantly white institutions (PWIs) for GSC. With Critical Race Theory (CRT) as my lens, I expand on mentoring, mentorship services, counter-storytelling, critical social factors and a historical context of higher education in order to both illustrate the problem and offer specific solutions to the systemic barriers that GSC face every day on college campuses. By leveraging the narrative side of CRT, this study provided the opportunity for additional GSC by creating a qualitative/quantitative survey designed to capture perceptions and experiences at other PWIs. These stories identify a trend or need for appropriate services in a system where GSC are attempting to navigate. The results offer specific counterstories by and experiential knowledge of GSC on mentoring at PWIs. There were two types: open-ended and Likert-scale. The survey results gave clarity on the specific topics it was designed to address. Respondents' overall attitudes and perceptions of mentoring show that mentees expect mentors to exhibit high levels of accessibility, approachability, trust, interest in a mentee's personal and academic welfare, especially as a person of color. Also, GSC expected at least some level of engagement with the mentee as a junior colleague, not merely as a student. Finally, GSC expected mentors to help navigate departmental academic support structures and policies as well as professional opportunities

Reductions in the dietary niche of southern sea otters (Enhydra lutris nereis) from the Holocene to the Anthropocene.

The sea otter (Enhydra lutris) is a marine mammal hunted to near extinction during the 1800s. Despite their well-known modern importance as a keystone species, we know little about historical sea otter ecology. Here, we characterize the ecological niche of ancient southern sea otters (E. lutris nereis) using δ13C analysis and δ15N analysis of bones recovered from archaeological sites spanning ~7,000 to 350 years before present (N = 112 individuals) at five regions along the coast of California. These data are compared with previously published data on modern animals (N = 165) and potential modern prey items. In addition, we analyze the δ15N of individual amino acids for 23 individuals to test for differences in sea otter trophic ecology through time. After correcting for tissue-specific and temporal isotopic effects, we employ nonparametric statistics and Bayesian niche models to quantify differences among ancient and modern animals. We find ancient otters occupied a larger isotopic niche than nearly all modern localities; likely reflecting broader habitat and prey use in prefur trade populations. In addition, ancient sea otters at the most southerly sites occupied an isotopic niche that was more than twice as large as ancient otters from northerly regions. This likely reflects greater invertebrate prey diversity in southern California relative to northern California. Thus, we suggest the potential dietary niche of sea otters in southern California could be larger than in central and northern California. At two sites, Año Nuevo and Monterey Bay, ancient otters had significantly higher δ15N values than modern populations. Amino acid δ15N data indicated this resulted from shifting baseline isotope values, rather than a change in sea otter trophic ecology. Our results help in better understanding the contemporary ecological role of sea otters and exemplify the strength of combing zooarchaeological and biological information to provide baseline data for conservation efforts

The threat of the ambrosia beetle Megaplatypus mutatus (Chapuis) (=Platypus mutatus Chapuis) to world poplar resources

We describe the life cycle of Megaplatypus mutatus (Chapuis) (=Platypus mutatus) and the damage it causes to poplar resources in Argentina. This insect, native to the subtropical and tropical areas of South America, has extended its range into temperate regions, reaching as far south as Neuquén in Argentinean Patagonia. The damage is caused by the adult insects, which bore large gallery systems into living poplars (Populus spp.), willows (Salix spp.) and many other broadleaf species, including important fruit trees species such as apples (Malus spp.), walnuts (Juglans spp.) and avocados (Persea spp.). The galleries degrade the lumber and weaken the tree stems, which often then break during windstorms. A recent introduction of M. mutatus to Italy demonstrates that this insect can be transported long distances between countries, and therefore presents a threat worldwide - particularly to poplar cultivation. We review the taxonomic nomenclature for this pest, provide a summary of the life cycle, hosts and damage and summarize actions taken to reduce the risk of introduction of M. mutatus to Canada.Facultad de Ciencias Agrarias y Forestale

No. 07: The Urban Food System of Mexico City, Mexico

This report provides an overview of Greater Mexico City and its food system. The city’s history, demographic characteristics, geography and economy are first discussed. The city’s urban food system and urban food security are then examined with a particular focus on formal and informal food retail, food expenditure patterns, and policies to combat hunger and food insecurity. Meeting the daily food demands of Mexico City’s over 20 million inhabitants requires the agricultural production of Mexico’s rural areas, its fishing industry and food imports. Food products arrive in the city from around the country in a combination of traditional and highly sophisticated modern systems of food supply and distribution. Structural changes in recent decades have led to modifications in the systems of supply, distribution and food consumption with vertically integrated companies now controlling aspects of the food chain. The system of supply and marketing of food products is also characterized by competition between public markets, large wholesale and retail companies, and neighbourhood convenience stores. While levels of household food insecurity (undernutrition) are lower than in other global cities of the South, Mexico City faces an epidemic of overnutrition, obesity and non-communicable diseases

Cavity-Based 3D Cooling of a Levitated Nanoparticle via Coherent Scattering

We experimentally realize cavity cooling of all three translational degrees of motion of a levitated nanoparticle in vacuum. The particle is trapped by a cavity-independent optical tweezer and coherently scatters tweezer light into the blue detuned cavity mode. For vacuum pressures around $10^{-5}\,{\rm mbar}$, minimal temperatures along the cavity axis in the mK regime are observed. Simultaneously, the center-of-mass (COM) motion along the other two spatial directions is cooled to minimal temperatures of a few hundred $\rm mK$. Measuring temperatures and damping rates as the pressure is varied, we find that the cooling efficiencies depend on the particle position within the intracavity standing wave. This data and the behaviour of the COM temperatures as functions of cavity detuning and tweezer power are consistent with a theoretical analysis of the experiment. Experimental limits and opportunities of our approach are outlined

Economia espacial e memória na América Latina

É com muito entusiasmo que apresentamos o terceiro número da PatryTer ”“ Revista Latinoamericana e Caribenha de Geografia e Humanidades. No mês de março de 2019, completamos o primeiro ano de existência. Os três primeiros números publicados revelam o grande desafio assumido pela equipe de edição e esboçam os enfrentamentos que temos pela frente, por diferentes motivos. Certamente, o maior desafio, nesses doze primeiros meses, foi o de iniciar e manter a revista sem apoio financeiro de qualquer agência nacional ou estrangeira. Todo o trabalho do periódico é realizado por integrantes do Grupo de Pesquisa CNPqCidades e Patrimonializacao na América Latina e Caribe, sediado no Departamento de Geografia da Universidade de Brasília e também coordenado pelo editor chefe da PatryTer. Lembro da colaboração incondicional de colegas de diferentes partes de nossa América, especialmente de Costa Rica, México, Cuba, Panamá, Argentina, Peru e Colômbia. Prova disso é que o presente número será apresentado no III Seminário Latinoamericano sobre Representacoes do Espaço, no Instituto de Geografía da UNAM, México, no mês de abril de 2019.É com muito entusiasmo que apresentamos o terceiro número da PatryTer ”“ Revista Latinoamericana e Caribenha de Geografia e Humanidades. No mês de março de 2019, completamos o primeiro ano de existência. Os três primeiros números publicados revelam o grande desafio assumido pela equipe de edição e esboçam os enfrentamentos que temos pela frente, por diferentes motivos. Certamente, o maior desafio, nesses doze primeiros meses, foi o de iniciar e manter a revista sem apoio financeiro de qualquer agência nacional ou estrangeira. Todo o trabalho do periódico é realizado por integrantes do Grupo de Pesquisa CNPqCidades e Patrimonializacao na América Latina e Caribe, sediado no Departamento de Geografia da Universidade de Brasília e também coordenado pelo editor chefe da PatryTer. Lembro da colaboração incondicional de colegas de diferentes partes de nossa América, especialmente de Costa Rica, México, Cuba, Panamá, Argentina, Peru e Colômbia. Prova disso é que o presente número será apresentado no III Seminário Latinoamericano sobre Representacoes do Espaço, no Instituto de Geografía da UNAM, México, no mês de abril de 2019.É com muito entusiasmo que apresentamos o terceiro número da PatryTer ”“ Revista Latinoamericana e Caribenha de Geografia e Humanidades. No mês de março de 2019, completamos o primeiro ano de existência. Os três primeiros números publicados revelam o grande desafio assumido pela equipe de edição e esboçam os enfrentamentos que temos pela frente, por diferentes motivos. Certamente, o maior desafio, nesses doze primeiros meses, foi o de iniciar e manter a revista sem apoio financeiro de qualquer agência nacional ou estrangeira. Todo o trabalho do periódico é realizado por integrantes do Grupo de Pesquisa CNPqCidades e Patrimonializacao na América Latina e Caribe, sediado no Departamento de Geografia da Universidade de Brasília e também coordenado pelo editor chefe da PatryTer. Lembro da colaboração incondicional de colegas de diferentes partes de nossa América, especialmente de Costa Rica, México, Cuba, Panamá, Argentina, Peru e Colômbia. Prova disso é que o presente número será apresentado no III Seminário Latinoamericano sobre Representacoes do Espaço, no Instituto de Geografía da UNAM, México, no mês de abril de 2019

Programming The Inverse Thermal Balance For A Bagasse-Fired Boiler, Including The Application Of A Optimization Method In MATLAB

Thermal balance of steam boilers can be done by two ways, the direct or indirect method; the direct method is not accurate. The reason why it is not accurate is that some operating parameters of biomass boilers cannot be obtained by direct measurements, like the measurement of fuel flow. These facts make it difficult to apply the direct method in the heat balance and force to use indirect one to determine these parameters and the boiler efficiency; hence, the indirect method is generally used for heat balance. Indirect method provides more accurate values and additionally, quantifies each of the energy losses, allowing to determinate causes of low efficiency of the equipment. Large amount of data involved implies the use of more affective calculation means; being iterative, assumed values for fuel flow must be compared with a value calculated until both match. In this work, the indirect method has been programmed in MATLAB; and for the preliminary fuel flow evaluation an optimization method could be used to prevent having to assume a value. Calculation details and a MATLAB algorithm are also presented

Ovarian and Adrenal Androgens and Their Link to High Human Chorionic Gonadotropin Levels: A Prospective Controlled Study

Background. Although the association between human chorionic gonadotropin (hCG) and hyperandrogenism was identified more than 40 years ago, relevant questions remain unanswered. Design and Methods. We conducted a prospective, longitudinal, and controlled study in 23 women with a diagnosis of a complete hydatidiform mole (HM). Results. All participants completed the study. Before HM evacuation mean hCG was markedly higher in the cases than in the control group (P≤0.001). Free testosterone (T) and dehydroepiandrosterone sulfate (DHEA-S) were found to be higher in the cases (2.78 ± 1.24 pg/mL and 231.50 ± 127.20 μ/dL) when compared to the control group (1.50 ± 0.75 pg/mL and 133.59 ± 60.69 μ/dL) (P=0.0001 and 0.001), respectively. There was a strong correlation between hCG and free T/total T/DHEA-S concentrations (r=0.78; P≤0.001, r=0.74;  P≤0.001, and r=0.71;  P≤0.001), respectively. In the cases group 48 hours after HM evacuation, hCG levels were found to be significantly lower when compared to initial levels (P=0.001) and free T and DHEA-S declined significantly (P=0.0002 and 0.009). Conclusion. Before uterus evacuation, hCG, free T, and DHEA-S levels were significantly higher when compared with controls finding a strong correlation between hCG and free T/DHEA-S levels. Forty-eight hours after HM treatment hCG levels declined and the difference was lost. A novel finding of our study is that in cases, besides free T, DHEA-S was also found to be significantly higher and both the ovaries and adrenal glands appear to be the sites of this androgen overproduction

Calculation of Response matrix of a BSS with 6LiI scintillator

The response matrix of a Bonner sphere spectrometer was calculated using MCNP 4C and MCNPX 2.4.0 codes. As thermal neutron detector a 0.4 cm £; 0.4 cm 6LiI which is located at the center of a set of polyethylene spheres. The response was calculated for 0, 2, 3, 5, 8, 10, and 12 inches-diameter polyethylene spheres for neutrons whose energy goes from 2.50E(-8) to 100 MeV. The response matrix was calculated for 23 neutron energies, the response functions were energy-interpolated to 51 neutron energies and were compared with a matrix response reported in the literature, in this comparison both response matrices are in agreement. The main differences were found in the bare detector and are attributed to the irradiation conditions and cross sections, for the other detectors the differences are due to the cross sections libraries