839 research outputs found

    Anti-VEGF Treatment Strategies for Wet AMD

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    Over the past few years, antivascular endothelial growth factor (VEGF) therapy has become a standard treatment for neovascular age-related macular degeneration (AMD). During this time, treatment strategies have evolved from a monthly dosing schedule to individualized regimens. This paper will review the currently available anti-VEGF agents and evidence-based treatment strategies

    The Viking seismometry

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    Efforts were made to determine the seismicity of Mars as well as define its internal structure by detecting vibrations generated by marsquakes and meteoroid impacts. The lack of marsquakes recognized in the Viking data made it impossible to make any direct inferences about the interior of Mars and only allowed the setting of upper bounds on the seismic activity of the planet. After obtaining more than 2100 hours worth of data during the quite periods at rates of one sample per second or higher, the Viking 2 seismometer was turned off as a consequence of a landing system failure. During the periods when adequate data were obtained, one event of possible seismic or meteoroid impact origin was recognized; however, there is a significant probability that this event was generated by a wind gust

    THE FIRST SM-ND ISOTOPIC DATA FOR METAMORPHIC ROCKS OF THE GUDJAL BLOCK IN THE EASTERN PART OF BUREYA CONTINENTAL MASSIF

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    It is the first time that there have been Sm-Nd isotopic geochemical studies conducted into the metamorphic rocks of the Gudjal block considered as a basement protrusion of the Bureya continental massif. It has been found that biotite and garnet-amphibole schists of the Gudjal formation are characterized by strongly negative εNd(0)=–15.7…–17.2 values and Paleoproterozoic values of Nd model age of tNd(DM)=2.4–2.1 Ga. Similar isotopic parameters are also typical of gneissic biotite granodiorites: εNd(0)=–18.7, tNd(DM)=1.8 Ga. Out of orthorocks of the Gudjal block studied, the Neoproterozoic orthogneisses and orthoamphibolites of the Tulovchikha formation and the Neoproterozoic gneiss-granites of the Nyatyngran complex of the Paleoproterozoic model age may be considered as a probable substrate for melts

    Seismology on Mars

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    A three-axis short period seismometer has been operating on the surface of Mars in the Utopia Planitia region since September 4, 1976. During the first five months of operation approx. 640 hours of high quality data, uncontaminated by Lander or wind noise, have been obtained. The detection threshold is estimated to be magnitude 3 to about 200 km and about 6.5 for the planet as a whole. No large events have been seen during this period indicating that Mars is less seismically active than Earth

    Late Miocene to early Pliocene biofacies of Wanganui and Taranaki Basins, New Zealand: Applications to paleoenvironmental and sequence stratigraphic analysis

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    The Matemateaonga Formation is late Miocene to early Pliocene (upper Tongaporutuan to lower Opoitian New Zealand Stages) in age. The formation comprises chiefly shellbeds, siliciclastic sandstone, and siltstone units and to a lesser extent non-marine and shallow marine conglomerate and rare paralic facies. The Matemateaonga Formation accumulated chiefly in shelf paleoenvironments during basement onlap and progradation of a late Miocene to early Pliocene continental margin wedge in the Wanganui and Taranaki Basins. The formation is strongly cyclothemic, being characterised by recurrent vertically stacked facies successions, bounded by sequence boundaries. These facies accumulated in a range of shoreface to mid-outer shelf paleoenvironments during conditions of successively oscillating sea level. This sequential repetition of facies and the biofacies they enclose are the result of sixth-order glacio-eustatic cyclicity. Macrofaunal associations have been identified from statistical analysis of macrofossil occurrences collected from multiple sequences. Each association is restricted to particular lithofacies and stratal positions and shows a consistent order and/or position within the sequences. This pattern of temporal paleoecologic change appears to be the result of lateral, facies-related shifting of broad biofacies belts, or habitat-tracking, in response to fluctuations of relative sea level, sediment flux, and other associated paleoenvironmental variables. The associations also show strong similarity in terms of their generic composition to biofacies identified in younger sedimentary strata and the modern marine benthic environment in New Zealand

    A multiscale analysis of gene flow for the New England cottontail, an imperiled habitat specialist in a fragmented landscape

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    Landscape features of anthropogenic or natural origin can influence organisms\u27 dispersal patterns and the connectivity of populations. Understanding these relationships is of broad interest in ecology and evolutionary biology and provides key insights for habitat conservation planning at the landscape scale. This knowledge is germane to restoration efforts for the New England cottontail (Sylvilagus transitionalis), an early successional habitat specialist of conservation concern. We evaluated local population structure and measures of genetic diversity of a geographically isolated population of cottontails in the northeastern United States. We also conducted a multiscale landscape genetic analysis, in which we assessed genetic discontinuities relative to the landscape and developed several resistance models to test hypotheses about landscape features that promote or inhibit cottontail dispersal within and across the local populations. Bayesian clustering identified four genetically distinct populations, with very little migration among them, and additional substructure within one of those populations. These populations had private alleles, low genetic diversity, critically low effective population sizes (3.2-36.7), and evidence of recent genetic bottlenecks. Major highways and a river were found to limit cottontail dispersal and to separate populations. The habitat along roadsides, railroad beds, and utility corridors, on the other hand, was found to facilitate cottontail movement among patches. The relative importance of dispersal barriers and facilitators on gene flow varied among populations in relation to landscape composition, demonstrating the complexity and context dependency of factors influencing gene flow and highlighting the importance of replication and scale in landscape genetic studies. Our findings provide information for the design of restoration landscapes for the New England cottontail and also highlight the dual influence of roads, as both barriers and facilitators of dispersal for an early successional habitat specialist in a fragmented landscape

    ПЕРВЫЕ SM-ND ИЗОТОПНЫЕ ДАННЫЕ ДЛЯ МЕТАМОРФИЧЕСКИХ ПОРОД ГУДЖАЛЬСКОГО БЛОКА ВОСТОЧНОЙ ЧАСТИ БУРЕИНСКОГО КОНТИНЕНТАЛЬНОГО МАССИВА

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    It is the first time that there have been Sm-Nd isotopic geochemical studies conducted into the metamorphic rocks of the Gudjal block considered as a basement protrusion of the Bureya continental massif. It has been found that biotite and garnet-amphibole schists of the Gudjal formation are characterized by strongly negative εNd(0)=–15.7…–17.2 values and Paleoproterozoic values of Nd model age of tNd(DM)=2.4–2.1 Ga. Similar isotopic parameters are also typical of gneissic biotite granodiorites: εNd(0)=–18.7, tNd(DM)=1.8 Ga. Out of orthorocks of the Gudjal block studied, the Neoproterozoic orthogneisses and orthoamphibolites of the Tulovchikha formation and the Neoproterozoic gneiss-granites of the Nyatyngran complex of the Paleoproterozoic model age may be considered as a probable substrate for melts.Впервые проведены Sm-Nd изотопно-геохимические исследования метаморфических пород Гуджальского блока, рассматриваемого в качестве «выступа» фундамента Буреинского континентального массива. Установлено, что биотитовые и гранат-амфиболовые ортосланцы гуджальской свиты характеризуются глубоко отрицательными значениями εNd(0) =–15.7…–17.2 и палеопротерозойскими величинами Nd модельного возраста tNd(DM)=2.4–2.1 млрд лет. Близкими изотопными параметрами характеризуются и гнейсовидные биотитовые гранодиориты: εNd(0)=–18.7, tNd(DM)=1.8 млрд лет. Для исследованных ортопород Гуджальского блока в качестве возможного субстрата для расплавов могут рассматриваться неопротерозойские ортогнейсы и ортоамфиболиты туловчихинской свиты, неопротерозойские гнейсограниты нятыгранского комплекса, обладающие палеопротерозойским модельным возрастом

    Relationships Among Alcohol Outlet Density, Alcohol use, and Intimate Partner Violence Victimization Among Young Women in the United States

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    Greater access to alcohol has been widely found to be associated with many negative outcomes including violence perpetration. This study examines the relationship between alcohol outlet density, alcohol use, and intimate partner violence (IPV) victimization among young women in the United States. A direct association between alcohol outlet density in one’s neighborhood and the likelihood of IPV victimization was examined. Data were from Wave III of the National Longitudinal Study of Adolescent Health (Add Health), which followed a nationally representative sample of adolescents into adulthood. Participants were young adult females age 18 to 26 at Wave III. Of the 4,571 female respondents who reported a current heterosexual relationship and had IPV data, 13.2% reported having been the victim of physical violence only and 6.5% experienced sexual only or physical and sexual violence in the relationship during the past year. In the regression models tested, there was no significant direct association between neighborhood alcohol outlet density and IPV victimization nor was there an association between outlet density and drinking behaviors, thus eliminating the possibility of an indirect association. Results of fully adjusted models indicate females who drank heavily, whether infrequently or frequently, were at significant risk for experiencing sexual only IPV or sexual and physical IPV. Asians and Native Americans were at significantly greater odds of experiencing sexual only or sexual and physical IPV compared with non-Hispanic Whites, while non-Hispanic Blacks were at significantly greater odds for physical only IPV. We conclude that a continuous measure of alcohol outlet density was not associated with IPV in models controlling for individual and other neighborhood characteristics. Young women who drink heavily, whether infrequently or frequently, have greater odds of experiencing sexual only or sexual and physical compared to abstainers. Similar to previous study findings, young women living with or married to their partner were at far greater risk of experiencing physical only and/or sexual only or sexual and physical IPV. The study adds to the growing body of literature that examines how community characteristics such as outlet density influence the likelihood of IPV
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