Singular Vectors of the Virasoro Algebra

We give expressions for the singular vectors in the highest weight representations of the Virasoro algebra. We verify that the expressions --- which take the form of a product of operators applied to the highest weight vector --- do indeed define singular vectors. These results explain the patterns of embeddings amongst Virasoro algebra highest weight representations.Comment: 15 p

Efectos de las interacciones electrostáticas sobre el potencial efectivo de líquidos moleculares

Esta tesis resume el trabajo realizado con potenciales efectivos sobre dos tipos de fluidos: el primero formado por moléculas que contienen dipolo eléctrico y el segundo con moléculas modeladas por cuerpos convexos. Los potenciales efectivos contienen un parámetro molecular extra, al de energía y al de distancia, que modifica el perfil del potencial con respecto a uno de referencia. El método empleado para ambos casos fue, esencialmente, trabajar con el promedio angular de las distintas configuraciones posibles entre dos moléculas y su posterior representación mediante un potencial efectivo simétricamente esférico; esto último se realiza mediante el principio de estados correspondientes. En el caso de moléculas convexas, el sistema efectivo representa adecuadamente el segundo coeficiente virial hallado por la termodinámica clásica de cuerpos convexos. En el caso polar, el potencial efectivo representa adecuadamente los primeros dos coeficientes viriales de un fluido teórico empleado regularmente en sistemas polares. Se ha incluido en dicho potencial un efecto de frustración energética entre dipolos lo cual ha permitido construir una ecuación de estado para este tipo de sistemas

La Importancia de la Radiología Forense

Resumen La identificación de los cadáveres es uno de los objetivos más importantes de la necropsia en grandes desastres, en este caso debido a una explosión, los cadáveres pueden presentar múltiples daños, mutilaciones, cuerpos quemados, restos de materiales de la explosión, tales como productos químicos, cuerpos extraños y objetos metálicos del componente desencadenante entre otros, lo que dificulta la aplicación de los métodos científicos más reconocidos, es aquí donde se utilizan los estudios radiológicos para identificar e individualizar los cadáveres mediante radiografías de la pelvis, identificación del sexo a través del orificio pélvico, en la radiografía del cráneo a través de las mastoides, estudio del carpograma, también de las diferentes señales particulares de cadáveres que pueden identificarse mediante un estudio radiológico para el proceso de identificación indiciaria, entre las señales particulares encontramos, prótesis ortopédicas, fracturas antiguas con formación de callos óseos, vértebras fusionadas, variantes anatómicas, vestimenta y artículos personales presentes en los cuerpos, las características individuales descritas por la familia o las personas cercanas a las víctimas y las encontradas durante el examen corporal, la identificación fehaciente utilizando métodos científicos, como la comparación de huellas digitales, la comparación dental y la comparación genética ácido desoxirribonucleico (ADN), (Cruz,2019 ).Summary The identification of the corpses is one of the most important objectives of the autopsy in major disasters, in this case due to an explosion, the corpses can present multiple damages, mutilations, burned bodies, remains of materials from the explosion, such as chemical products , foreign bodies and metallic objects of the triggering component among others, which makes it difficult to apply the most recognized scientific methods, it is here that radiological studies are used to identify and individualize the corpses by means of radiographs of the pelvis, identification of sex through the pelvic orifice, in the x-ray of the skull through the mastoids, study of the carpogram, also of the different particular signs of corpses that can be identified by means of a radiological study for the identification process, among the particular signs we find orthopedic prostheses, fractures old with bone callus formation os, fused vertebrae, anatomical variants, clothing and personal items present in the bodies, the individual characteristics described by the family or people close to the victims and those found during the body examination, reliable identification using scientific methods, such as the comparison of fingerprints, dental comparison and deoxyribonucleic acid (DNA) genetic comparison

Acute-Stress Biomarkers in Three Octopodidae Species After Bottom Trawling

Several Octopodidae species have a great potential for the diversification of worldwide aquaculture. Unfortunately, the lack of stress-related biomarkers in this taxon results an obstacle for its maintenance in conditions where animal welfare is of paramount relevance. In this study, we made a first approach to uncover physiological responses related to fishing capture in Eledone moschata, Eledone cirrhosa, and Octopus vulgaris. Captured octopus from all three species were individually maintained in an aquaculture system onboard of oceanographic vessel in south-western waters of Europe. Haemolymph plasma and muscle were collected in animals at the moment of capture, and recovery was evaluated along a time-course of 48 h in Eledone spp., and 24 h for O. vulgaris. Survival rates of these species captured in spring and autumn were evaluated. Physiological parameters such as plasma pH, total CO2, peroxidase activity, lysozyme, hemocyanin, proteases, pro-phenoloxidase, anti-proteases, free amino acids, lactate and glucose levels, as well as muscle water percentage, free amino acids, lactate, glycogen and glucose values were analyzed. The immune system appears to be compromised in these species due to capture processes, while energy metabolites were mobilized to face the acute-stress situation, but recovery of all described parameters occurs within the first 24 h after capture. Moreover, this situation exerts hydric balance changes, as observed in the muscle water, being these responses depending on the species assessed. In conclusion, three Octopodidae species from south-western waters of Europe have been evaluated for stress-related biomarkers resulting in differentiated mechanisms between species. This study may pave the way to further study the physiology of stress in adult octopuses and develop new methodologies for their growth in aquaculture conditions

Burn severity influences postfire CO2 exchange in Arctic tundra

Author Posting. © Ecological Society of America, 2011. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 21 (2011): 477–489, doi:10.1890/10-0255.1.Burned landscapes present several challenges to quantifying landscape carbon balance. Fire scars are composed of a mosaic of patches that differ in burn severity, which may influence postfire carbon budgets through damage to vegetation and carbon stocks. We deployed three eddy covariance towers along a burn severity gradient (i.e., severely burned, moderately burned, and unburned tundra) to monitor postfire net ecosystem exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar in Alaska, USA, during the summer of 2008. Remote sensing data from the MODerate resolution Imaging Spectroradiometer (MODIS) was used to assess the spatial representativeness of the tower sites and parameterize a NEE model that was used to scale tower measurements to the landscape. The tower sites had similar vegetation and reflectance properties prior to the Anaktuvuk River fire and represented the range of surface conditions observed within the fire scar during the 2008 summer. Burn severity influenced a variety of surface properties, including residual organic matter, plant mortality, and vegetation recovery, which in turn determined postfire NEE. Carbon sequestration decreased with increased burn severity and was largely controlled by decreases in canopy photosynthesis. The MODIS two-band enhanced vegetation index (EVI2) monitored the seasonal course of surface greenness and explained 86% of the variability in NEE across the burn severity gradient. We demonstrate that understanding the relationship between burn severity, surface reflectance, and NEE is critical for estimating the overall postfire carbon balance of the Anaktuvuk River fire scar.This work was supported by NSF grants #0632139 (OPP-AON), #0808789 (OPP-ARCSS SGER), #0829285 (DEB-NEON SGER), and #0423385 (DEBLTER) to the Marine Biological Laboratory

Differential responses of ecotypes to climate in a ubiquitous arctic sedge: implications for future ecosystem C cycling

The response of vegetation to climate change has implications for the carbon cycle and global climate. It is frequently assumed that a species responds uniformly across its range to climate change. However, ecotypes—locally adapted populations within a species—display differences in traits, which may affect their gross primary productivity (GPP) and response to climate change. To determine if ecotypes are important for understanding the response of ecosystem productivity to climate we measured and modeled growing season GPP in reciprocally transplanted and experimentally warmed ecotypes of the abundant arctic sedge Eriophorum vaginatum. Transplanted northern ecotypes displayed home site advantage in GPP that was associated with differences in leaf area index. Southern ecotypes exhibited a greater response in GPP when transplanted. The results demonstrate that ecotypic differentiation can impact the morphology and function of vegetation with implications for carbon cycling. Moreover they suggest that ecotypic control of GPP may limit the response of ecosystem productivity to climate change. This investigation shows that ecotypes play a substantial role in determining GPP and its response to climate. These results have implications for understanding annual to decadal carbon cycling where ecotypes could influence ecosystem function and vegetation feedbacks to climate change

Extensão da distribuição geográfica de Plecturocebus baptista (Pitheciidae, Primates) e uma possível zona híbrida com Plecturocebus hoffmannsi: implicações evolutivas e de conservação

Titi monkeys (family Pitheciidae) are Neotropical primates highly diversified in morphology, ecology and genetics, with a wide geographic distribution, including the Amazon, Atlantic Forest, Cerrado, Pantanal and Caatinga. This diversity, together with knowledge gaps, generates uncertainties in titi monkey taxonomy and distribution. An example is Plecturocebus baptista, with only 14 occurrence records and an ill-defined distribution based on untested geographical barriers. Here, we report the occurrence of this species at a new locality outside its known range, across the Paraná-Urariá River, which was considered a distributional limit for the species. The new record implies an overlap of P. baptista with the range of P. hoffmannsi. We document the sighting of an apparent hybrid animal. Our observations suggest that i) the distribution of P. baptista needs to be reviewed, and ii) the evolutionary relationships between P. baptista and P. hoffmannsi may be more complex than previously assumed. Since both species share contiguous areas of potential hybridization, we question whether the two species arose via allopatric speciation.Macacos zogue-zogue (família Pitheciidae) são primatas neotropicais altamente diversificados em morfologia, ecologia e genética, com distribuição geográfica abrangente, incluindo a Floresta Amazônica, Mata Atlântica, Cerrado, Pantanal e a Caatinga. Essa diversificação, juntamente com lacunas de conhecimento, gera incertezas na taxonomia e distribuição das espécies. Um exemplo é Plecturocebus baptista, com apenas 14 registros de ocorrência e distribuição indefinida, baseada em barreiras geográficas não testadas. Aqui nós relatamos a ocorrência da espécie em uma nova localidade, fora de sua área conhecida de distribuição, que transpõe uma suposta barreira geográfica, o Rio Paraná-Urariá. O novo registro de P. baptista se sobrepõe à distribuição de P. hoffmannsi e, neste contexto, observamos um indivíduo aparentemente híbrido entre as duas espécies. Nossas observações sugerem que i) a distribuição de P. baptista necessita ser revisada, e ii) a relação evolutiva entre P. baptista e P. hoffmannsi pode ser mais complexa do que se pensava. Como ambas espécies compartilham áreas contínuas de potencial hibridização, questionamos se as duas espécies resultaram de especiação alopátrica

Contrasting soil thermal responses to fire in Alaskan tundra and boreal forest

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Earth Surface 120 (2015): 363–378, doi:10.1002/2014JF003180.Recent fire activity throughout Alaska has increased the need to understand postfire impacts on soils and permafrost vulnerability. Our study utilized data and modeling from a permafrost and ecosystem gradient to develop a mechanistic understanding of the short- and long-term impacts of tundra and boreal forest fires on soil thermal dynamics. Fires influenced a variety of factors that altered the surface energy budget, soil moisture, and the organic-layer thickness with the overall effect of increasing soil temperatures and thaw depth. The postfire thickness of the soil organic layer and its impact on soil thermal conductivity was the most important factor determining postfire soil temperatures and thaw depth. Boreal and tundra ecosystems underlain by permafrost experienced smaller postfire soil temperature increases than the nonpermafrost boreal forest from the direct and indirect effects of permafrost on drainage, soil moisture, and vegetation flammability. Permafrost decreased the loss of the insulating soil organic layer, decreased soil drying, increased surface water pooling, and created a significant heat sink to buffer postfire soil temperature and thaw depth changes. Ecosystem factors also played a role in determining postfire thaw depth with boreal forests taking several decades longer to recover their soil thermal properties than tundra. These factors resulted in tundra being less sensitive to postfire soil thermal changes than the nonpermafrost boreal forest. These results suggest that permafrost and soil organic carbon will be more vulnerable to fire as climate warms.We are pleased to acknowledge funding from the US National Science Foundation, grants DEB-1026843 and EF-1065587, to the Marine Biological Laboratory. Additional logistical support was provided by Toolik Field Station and CH2MHill, funded by NSF's Office of Polar Programs.2015-08-2

Testing the link between terrestrial climate change and Galactic spiral arm transit

We re-examine past suggestions of a close link between terrestrial climate change and the Sun's transit of spiral arms in its path through the Milky Way galaxy. These links produced concrete fits, deriving the unknown spiral pattern speed from terrestrial climate correlations. We test these fits against new data on spiral structure based on CO data that does not make simplifying assumptions about symmetry and circular rotation. If we compare the times of these transits to changes in the climate of Earth, not only do the claimed correlations disappear, but also we find that they cannot be resurrected for any reasonable pattern speed.Comment: Accepted for publication in ApJ Letters. Moderate revisions with clarification, no change in conclusion

Collared forest-falcon (Micrastur semitorquatus) preying on a squirrel in a fragment of atlantic forest with a revision of the predation events for the species

We recorded predation on the squirrel Guerlinguetus ingrami by a Collared Forest-Falcon (Micrastur semitorquatus) through camera trapping in a forest fragment of Atlantic Forest in the interior of São Paulo state, Brazil. The squirrel was captured while it moved across the forest floor. A compilation from bibliographic and other sources resulted in 68 vertebrate and 03 invertebrate species as prey of the Collared Forest-Falcon, with birds more commonly reported in the diet of the species. The majority of prey (66% of species) did not exceed 300 g, but some prey species (12%) such as guans (Penelope spp.) were heavier than the falcon. The Collared Forest-Falcon could affect the population dynamics of smaller vertebrates in forest fragments of Atlantic Forest due to its flexibility in diet and habitat use, an aspect that deserve a more thorough investigation. © 2017, Sociedade Brasileira de Ornitologia. All rights reserved