Photooxidation of Biopolymers

The lack of degradation of plastic products have imposed problems in the preservation of natural environments and their ecosystems through plastic accumulation. This collection of plastics promotes toxin exposure to wildlife, finding its way into the food chain, affecting both land and marine ecosystems. The project goal is to understand the degradation mechanisms of biodegradable materials and other comparable materials through UV radiation testing. Polylactide (PLA) films and polycarbonate (PC) films will be compared for their relative deterioration from constant UV radiation in a Q-U-V accelerated weather tester for 28 days. Five 3” by 5” samples of 14 mil thick and 16 mil thick PLA films along with 15 mil thick PC films were prepared for ultraviolet exposure. Mechanical and microstructural property changes will be monitored by tensile testing using ASTM D882 procedure, differential scanning calorimetry, and FT-infrared spectroscopy. Based on preliminary observations, there are no signs suggesting PLA will degrade to a greater extent than PC

Disentangling the signal of climatic fluctuations from land use: changes in ecosystem functioning in South American protected areas (1982-2012)

Global environmental change is characterized by changing climate, atmospheric composition and land use. Its impact on ecosystem structure and functioning has been detected throughout the world. While every ecosystem is vulnerable to climate change, the degree of the impact and the magnitude of the ecosystem response are likely to vary. Protected areas of South America provide a ‘laboratory’ to test expectations of climate change effects on ecosystems at a regional scale. By using protected areas we minimized the effects of land use/land cover changes over ecosystem functioning. We analyzed the temporal trends, that is, directional changes, and spatial heterogeneity of both climatic variables and attributes of the seasonal dynamics of the normalized difference vegetation index, that is, a surrogate of vegetation carbon gains derived from satellite information, on 201 protected areas of South America. Increased productivity and higher seasonality, frequently climate driven, is the most common signal across South American biomes but concentrated on those areas located in the tropics and subtropics. In general, arid and semiarid sites responded positively to increases in precipitation and negatively to increases in temperature, while humid ecosystems responded in the opposite way. Our results provide a preliminary basis for predicting which ecosystems will respond more rapidly and strongly to climate change. We also provide support to the fact that protected areas are not static systems as their functioning is changing with different magnitude and in contrasting directions

Building A Health Administration Program: Strategies For Success

Nearly 200 students have now graduated from the University of Baltimore’s (UB’s) six-year-old undergraduate Health Systems Management program (HSMG). With a total student enrollment of 113, the program is one of the larger health administration programs in the United States. The program, an affiliate member of the Association of University Programs in Health Administration, is a unique weekend program that allows working professionals with an Associate’s degree to complete a Bachelor of Science degree in 2½ years. The students have, on average, 10–15 years of experience in the heath industry either as nurses or radiology technicians, thus bringing extensive practical experience to the classroom. By any academic measure, the program has been a success. Recruitment is strong and steady, the retention rate and graduation rate (over 80 percent) is high compared to both the university and national averages, and over 90 percent of the graduating students finish in the 2½ years. The purpose of this paper is to discuss the issues and strategies involved in implementing the program, as well as some of the unique features of this program. We believe our success can be replicated in other university and program settings. The health care employment market in the greater Baltimore region provided a significant student population base from which we were able to draw for enrollment in our HSMG program. Other regional markets can be addressed in a similar fashion to meet the educational needs of students and enhance the achievement of university enrollment goals

Effect on Irradiance of the eruption of the Cordon Caulle (Chile) at different altitudes in the Nahuel Huapi National Park (Patagonia, Argentina)

Volcanic eruptions inject ash and non-ash particles into the atmosphere, modifying regional Aerosols Optical Depth (AOD) and aerosols size distribution, which affect irradiance at the earth’s surface. In this paper, we analyze the effect of the eruption of Puyehue-Cordon Caulle (Chile) on irradiance in the area of the Nahuel Huapi National Park (NHNP) (~100 km southeast of Puyehue-Cordon Caulle), at different altitudes. In this paper we only included the results for direct and AOD obtained during field campaigns at two consecutive years, before and after the eruption. Three days presented clear skies during most of the day in 2011. Two of those days, showed AOD similar to the values in 2010. On the third days, at the lowest altitude site (804m.s.l.), AOD were near 200% larger than in 2010. The largest decreases observed, at noon, in the direct irradiance was ~30% at 380 nm and 25% at 500nm, increasing with Solar Zenith Angle (SZA). The effect was less pronounced at the site at highest altitude (1930 m.s.l.), where the AODs increase was near 90% and the direct noon irradiance decrease 10% at 380 nm and 7% at 500nm. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.Fil: Diaz, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Paladini, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Braile, H. G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Dieguez, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vernet, María. University of California at San Diego; Estados UnidosFil: Vrsalovic, Jazmin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Estradiol regulates brown adipose tissue thermogenesis via hypothalamic AMPK

Copyright © 2014 Elsevier Inc. All rights reserved.Peer reviewedPublisher PD

Acceptability of Tenofovir Gel as a Vaginal Microbicide Among Women in a Phase I Trial: A Mixed-Methods Study

Objectives: In this phase I safety trial of tenofovir gel, a candidate vaginal microbicide for human immunodeficiency virus (HIV) prevention, a mixed-methods design was used to gather acceptability data among women participants. The impact of acceptability factors on use of the gel and the relationship between qualitative and quantitative acceptability data are explored. Methods: Participants included low-risk, HIV-uninfected, and clinically stable HIV-infected women. Participants were enrolled into cohorts stratified by HIV serostatus, sexual activity, gel concentration, and frequency of use. Quantitative data were collected via interviewer-administered structured questionnaires. Qualitative data were collected via semistructured small group discussions. Results: Although 94% of participants stated they would “probably” or “definitely” use tenofovir gel, a range of responses emerged on multiple domains relevant to microbicide acceptability during the qualitative discussions. Lubrication, leakage, sexual pleasure, and the possibility of covert use were central to women's qualitative assessments of tenofovir gel. Conclusions: Quantitative results indicate that tenofovir vaginal gel was acceptable to almost all users, while qualitative findings indicate that acceptability is complex, varies among users, and is likely shaped by a variety of contextual factors that manufacturers will need to consider to optimize use-effectiveness. Because of the differences in the qualitative and quantitative responses, the authors argue that future trials of candidate microbicides should include strategic collection of mixed-methods microbicide acceptability data

Los latidos del tiempo: un viaje imaginario desde el origen del universo hasta nuestros días

El conocimiento científico provisorio y cambiante, nos permite entender la realidad que nos rodea de una determinada manera. Esta no es la única forma de comprender nuestro universo pero sin duda explica los fenómenos de un modo racional y empírico. Esto se realiza mediante la formulación de hipótesis, la corroboración y contrastación de las mismas, comunicando los resultados y abriendo el juego a diversas opiniones que, lejos de criticar destructivamente, afianzan los conocimientos, solidificando las bases en una construcción colectiva del saber (Desantes-Guanter et al 2000). Este es el espíritu que se transmite a quienes participan de Latidos del Tiempo; una propuesta de extensión. Un recorrido guiado por especialistas en astronomía, zoología, ecología, biología de la conservación y antropología, que articula tres importantes centros de formación, divulgación y entretenimiento: el Observatorio Astronómico, el Museo de Ciencias Naturales y el Jardín Zoológico y Botánico de La Plata. La actividad, abarca los hitos más importantes de la evolución cósmica. Comienza con el Big Bang, incursionando por el Origen de la Vida y el Origen del Hombre hasta el presente, reflexionando sobre las problemáticas ambientales actuales y sobre nuestra responsabilidad como especie racional sobre el Planeta. El desafío y principal logro de la actividad, consiste en abordar cada tema de manera amena y multidisciplinar pero desdibujando los límites de cada disciplina, tratando de que los participantes experimenten la continuidad de los diversos hitos, integrando y relacionando los eventos, discutiendo ante distintas interpretaciones y generando nuevos interrogantes, más que de respuestas definitivas.Trabajos del área Ciencias NaturalesDepartamento de Ciencias Exactas y Naturale