Dioszegia antarctica sp. nov. and Dioszegia cryoxerica sp. nov., psychrophilic basidiomycetous yeasts from polar desert soils in Antarctica

International Journal of Systematic and Evolutionary Microbiology, 60

Acute Chagas' cardiopathy in a polar bear (Ursus maritimus) in Guadalajara, Mexico

We report a 24 year old female polar bear (Ursus maritimus) who contracted Chagas' infection at the Guadalajara Zoo, in Jalisco, México, and died of acute Chagas' carditis 15 days later. The histopathological findings are described, as well as the presence of triatomines (Triatoma longipennis Usinger) infected with Trypanosoma cruzi collected within 5 meters from the place where the animal lived in the city of Guadalajara.

Estación Astronómica Polar J. L. Sersic

- El grupo IATE del Observatorio Astronómico Córdoba está desarrollando un proyecto observacional en el antártico, desde 1989, denominado ASTROLABEL. Las observaciones se realizan en Base Antártica Belgrano, a 78º S y 34º W, siendo el sitio más adecuado según la prospección hecha en las bases argentinas de actividad permanente. - Se pretende determinar cualitativamente la aptitud de la atmósfera polar para realizar observaciones astronómicas en el rango visible del espectro. Las especiales cirscunstancias de la región, como lo son su prolongado período de oscuridad invernal, la inexistencia de contaminación atmosférica y lumínica y los bajos niveles de humedad relativa, han despertado el interés de los investigadores. - Las tareas se desarrollan en convenio con el Instituto Antártico Argentino (IAA). Objetivos Se pretende determinar cualitativa y cuantitativamente las condiciones del cielo del lugar, para la ejecución de trabajos astronómicos de interés. (...) La disponibilidad de muchas horas de observación continuada hace posible el monitoreo de estrellas con una frecuencia de varias veces al día, lo que permitirá obtener su curva de luminosidad completa, sin interrumpir las observaciones por la salida del sol. Esta situación es la que permitirá la observación de Eta Carina, estrella que presenta bruscos y sorprendentes cambios en su luminosidad. Similar es el caso de las estrellas variables R Corona Borealis con cambios esporádicos, aunque de bajo valor en su brillo. Estas observaciones demandan de un monitoreo constante y con una frecuencia de al menos dos o tres veces diarias. Se pretende obtener una conclusión sobre la transparencia en el UV, cuando se produce la apertura de la depresión de ozono, para lo cual se obtendrá una correlación entre las mediciones de los índices de esa banda y las mediciones de ozono hechas en el lugar con medidores Brewer y EVA. También se tomarán datos con radiómetro de sol durante el verano.

Polar S810 como recurso alternativo ao eletrocardiograma no teste de exercício de 4 segundos

FUNDAMENTO: O teste de exercício de 4 segundos (T4s) avalia o tônus vagal cardíaco durante o transiente inicial da frequência cardíaca (FC), em exercício dinâmico súbito, por meio da identificação do índice vagal cardíaco (IVC) obtido a partir do eletrocardiograma (ECG). OBJETIVO: Testar a utilização do monitor de frequência cardíaca (MFC) Polar S810 como recurso alternativo ao ECG na aplicação do T4s. MÉTODOS: Neste trabalho, 49 indivíduos do sexo masculino (25 ± 20 anos, 176 ± 12 cm, 74 ± 6 kg) realizaram o T4s. Os intervalos RR foram registrados simultaneamente por ECG e MFC. Calcularam-se média e desvio padrão do último intervalo RR do período pré-exercício ou o primeiro do período de exercício, aquele que for mais longo (RRB), do mais curto intervalo RR do período de exercício (RRC) e do IVC obtidos por ECG e MFC. Utilizou-se o teste t de Student para amostras dependentes (p < 0,05) para testar a significância das diferenças entre as médias. Para identificar a concordância entre o ECG e o MFC, utilizou-se a regressão linear, com cálculo do coeficiente de correlação de Pearson e a estratégia proposta por Bland e Altman. RESULTADOS: A regressão linear apresentou r² de 0,9999 para o RRB, 0,9997 para o RRC e 0,9996 para o IVC. A estratégia de Bland e Altman apresentou desvio padrão de 0,92 ms para o RRB, 0,86 ms para o RRC e 0,002 para o IVC. CONCLUSÃO: O MFC Polar S810 se mostrou eficiente na aplicação do T4s quando comparado ao ECG.

Growth of semi-polar GaN on high index silicon (11h) substrates by metal organic vapor phase epitaxy

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2014

Note on homology of expanding foliations

This note contains some remarks about the homologies that can be associated to a foliation which is invariant and uniformly expanded by a diffeomorphism. We construct a family of 'dynamical' closed currents supported on the foliation which help us relate the geometric volume growth of the leaves under the diffeomorphism with the map induced on homology in the case when these currents have nonzero homology.

Energetics of RecA-mediated recombination reactions. Without ATP hydrolysis RecA can mediate polar strand exchange but is unable to recycle.

We demonstrate that the step of DNA strand exchange during RecA-mediated recombination reaction can occur equally efficiently in the presence or absence of ATP hydrolysis. The polarity of strand exchange is the same when instead of ATP its non-hydrolyzable analog adenosine-5'-O-(3-thiotriphosphate) is used. We show that the ATP dependence of recombination reaction is limited to the post-exchange stages of the reactions. The low DNA affinity state of RecA protomers, induced after ATP hydrolysis, is necessary for the dissociation of RecA-DNA complexes at the end of the reaction. This dissociation of RecA from DNA is necessary for the release of recombinant DNA molecules from the complexes formed with RecA and for the recycling of RecA protomers for another round of the recombination reaction.

Modified differentials and basic cohomology for Riemannian foliations

We define a new version of the exterior derivative on the basic forms of a Riemannian foliation to obtain a new form of basic cohomology that satisfies Poincaré duality in the transversally orientable case. We use this twisted basic cohomology to show relationships between curvature, tautness, and vanishing of the basic Euler characteristic and basic signature.

Index theory for basic Dirac operators on Riemannian foliations

In this paper we prove a formula for the analytic index of a basic Dirac-type operator on a Riemannian foliation, solving a problem that has been open for many years. We also consider more general indices given by twisting the basic Dirac operator by a representation of the orthogonal group. The formula is a sum of integrals over blowups of the strata of the foliation and also involves eta invariants of associated elliptic operators. As a special case, a Gauss-Bonnet formula for the basic Euler characteristic is obtained using two independent proofs.

Polar gradients of the DYRK-family kinase Pom1 couple cell length with the cell cycle.

Cells normally grow to a certain size before they enter mitosis and divide. Entry into mitosis depends on the activity of Cdk1, which is inhibited by the Wee1 kinase and activated by the Cdc25 phosphatase. However, how cells sense their size for mitotic commitment remains unknown. Here we show that an intracellular gradient of the dual-specificity tyrosine-phosphorylation regulated kinase (DYRK) Pom1, which emanates from the ends of rod-shaped Schizosaccharomyces pombe cells, serves to measure cell length and control mitotic entry. Pom1 provides positional information both for polarized growth and to inhibit cell division at cell ends. We discovered that Pom1 is also a dose-dependent G2-M inhibitor. Genetic analyses indicate that Pom1 negatively regulates Cdr1 and Cdr2, two previously described Wee1 inhibitors of the SAD kinase family. This inhibition may be direct, because in vivo and in vitro evidence suggest that Pom1 phosphorylates Cdr2. Whereas Cdr1 and Cdr2 localize to a medial cortical region, Pom1 forms concentration gradients from cell tips that overlap with Cdr1 and Cdr2 in short cells, but not in long cells. Disturbing these Pom1 gradients leads to Cdr2 phosphorylation and imposes a G2 delay. In short cells, Pom1 prevents precocious M-phase entry, suggesting that the higher medial Pom1 levels inhibit Cdr2 and promote a G2 delay. Thus, gradients of Pom1 from cell ends provide a measure of cell length to regulate M-phase entry.

In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii

The polar hydroethanolic extract from Selaginella sellowii(SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis.