Algoritmos de Detecçao de Taquicardias Incorporado a Desfibriladores Automáticos Implantáveis. 1) Desfibriladores Monocamerais

Diversos algoritmos foram incorporados aos cardioversores-desfibriladores automáticos implantáveis (CDIs) para identificar os distúrbios do ritmo ventricular e, sobretudo, para os diferenciar de taquicardias supraventriculares que nao necessitam terapia. Esses benefícios também sao encontrados nos CDIs bicamerais que têm como benefício a detecçao atrial acoplada à detecçao do ventrículo. O objetivo dos algoritmos é de identificar todas as arritmias ventriculares (sensibilidade de 100%), para que sejam tratadas corretamente. Devem ainda evitar erros de identificaçao de arritmias supraventriculares (especificidade máxima). Infelizmente, nao é possível alcançar 100% de sensibilidade e especificidade. Além disso, todo aumento da especificidade será acompanhado por uma diminuiçao da sensibilidade. Essa diminuiçao de especificidade pode conduzir a falha na detecçao dos distúrbios do ritmo ventricular, e como conseqüência, isto é pior que o tratamento inadequado de uma taquicardia sinusal ou supraventricular

Algoritmos de Detecçao de Taquicardias Incorporado a Desfibriladores Automáticos Implantáveis. 1) Desfibriladores Monocamerais

Diversos algoritmos foram incorporados aos cardioversores-desfibriladores automáticos implantáveis (CDIs) para identificar os distúrbios do ritmo ventricular e, sobretudo, para os diferenciar de taquicardias supraventriculares que nao necessitam terapia. Esses benefícios também sao encontrados nos CDIs bicamerais que têm como benefício a detecçao atrial acoplada à detecçao do ventrículo. O objetivo dos algoritmos é de identificar todas as arritmias ventriculares (sensibilidade de 100%), para que sejam tratadas corretamente. Devem ainda evitar erros de identificaçao de arritmias supraventriculares (especificidade máxima). Infelizmente, nao é possível alcançar 100% de sensibilidade e especificidade. Além disso, todo aumento da especificidade será acompanhado por uma diminuiçao da sensibilidade. Essa diminuiçao de especificidade pode conduzir a falha na detecçao dos distúrbios do ritmo ventricular, e como conseqüência, isto é pior que o tratamento inadequado de uma taquicardia sinusal ou supraventricular

A 310 nm Optically Pumped AlGaN Vertical-Cavity Surface-Emitting Laser

Ultraviolet light is essential for disinfection, fluorescence excitation, curing, and medical treatment. An ultraviolet light source with the small footprint and excellent optical characteristics of vertical-cavity surface-emitting lasers (VCSELs) may enable new applications in all these areas. Until now, there have only been a few demonstrations of ultraviolet-emitting VCSELs, mainly optically pumped, and all with low Al-content AlGaN cavities and emission near the bandgap of GaN (360 nm). Here, we demonstrate an optically pumped VCSEL emitting in the UVB spectrum (280-320 nm) at room temperature, having an Al0.60Ga0.40N cavity between two dielectric distributed Bragg reflectors. The double dielectric distributed Bragg reflector design was realized by substrate removal using electrochemical etching. Our method is further extendable to even shorter wavelengths, which would establish a technology that enables VCSEL emission from UVA (320-400 nm) to UVC (<280 nm)

Advances in the Direct Study of Carbon Burning in Massive Stars

The C12+C12 fusion reaction plays a critical role in the evolution of massive stars and also strongly impacts various explosive astrophysical scenarios. The presence of resonances in this reaction at energies around and below the Coulomb barrier makes it impossible to carry out a simple extrapolation down to the Gamow window-the energy regime relevant to carbon burning in massive stars. The C12+C12 system forms a unique laboratory for challenging the contemporary picture of deep sub-barrier fusion (possible sub-barrier hindrance) and its interplay with nuclear structure (sub-barrier resonances). Here, we show that direct measurements of the C12+C12 fusion cross section may be made into the Gamow window using an advanced particle-gamma coincidence technique. The sensitivity of this technique effectively removes ambiguities in existing measurements made with gamma ray or charged-particle detection alone. The present cross-section data span over 8 orders of magnitude and support the fusion-hindrance model at deep sub-barrier energies

'Leader, you first': The everyday production of hierarchical space in a Chinese bureaucracy

Recent studies highlight how organizational power relations are materialized in space. However, relatively little is known about how these spatialized power relations are reproduced on a day-to-day basis. Drawing on a ten-month ethnographic study of a large government office in China, we find that hierarchical space is produced through three intertwined processes. It proliferates as employees actively seek out signs of hierarchy in the organization’s space; it becomes familiarized as employees fabricate and circulate fanciful narratives about their spatial environs; and it is ritualized by employees acting out hierarchical relations across the organization’s space. These processes resulted in a hardening of the hierarchical relations of power. The study extends the existing literature by showing how hierarchical organizational space is not just something that is imposed on employees; it is also imposed by the employees themselves

The impact of neogene grassland expansion and aridification on the isotopic composition of continental precipitation

The late Cenozoic was a time of global cooling, increased aridity, and expansion of grasslands. In the last two decades numerous records of oxygen isotopes have been collected to assess plant ecological changes, understand terrestrial paleoclimate, and to determine the surface history of mountain belts. The δ¹⁸(O) values of these records, in general, increase from the mid-Miocene to the Recent. We suggest that these records record an increase in aridity and expansion of grasslands in midlatitude continental regions. We use a nondimensional isotopic vapor transport model coupled with a soil water isotope model to evaluate the role of vapor recycling and transpiration by different plant functional types. This analysis shows that increased vapor recycling associated with grassland expansion along with biomechanistic changes in transpiration by grasses themselves conspires to lower the horizontal gradient in the δ¹⁸(O) of atmospheric vapor as an air mass moves into continental interiors. The resulting signal at a given inland site is an increase in δ¹⁸(O) of precipitation with the expansion of grasslands and increasing aridity, matching the general observed trend in terrestrial Cenozoic δ¹⁸(O) records. There are limits to the isotopic effect that are induced by vapor recycling, which we refer to here as a “hydrostat.” In the modern climate, this hydrostatic limit occurs at approximately the boundary between forest and grassland ecosystems

On violating one’s own privacy: N-adic utterances and inadvertent disclosures in online venues

Purpose: To understand the phenomena of people revealing regrettable information on the Internet, we examine who people think they’re addressing, and what they say, in the process of interacting with those not physically or temporally co-present. Design/methodology/approach: We conduct qualitative analyses of interviews with student bloggers and observations of five years’ worth of their blog posts, drawing on linguists’ concepts of indexical ground and deictics. Based on analyses of how bloggers reference their shared indexical ground and how they use deictics, we expose bloggers’ evolving awareness of their audiences, and the relationship between this awareness and their disclosures. Findings: Over time, writers and their regular audience, or “chorus,” reciprocally reveal personal information. However, since not all audience members reveal themselves in this venue, writers’ disclosures are available to those observers they are not aware of. Thus, their over-disclosure is tied to what we call the “n-adic” organization of online interaction. Specifically, and as can be seen in their linguistic cues, N-adic utterances are directed towards a non-unified audience whose invisibility makes the discloser unable to find out the exact number of participants or the time they enter or exit the interaction. Research implications: Attention to linguistic cues, such as deictics, is a compelling way to identify the shifting reference groups of ethnographic subjects interacting with physically or temporally distant others. Originality/value: We describe the social organization of interaction with undetectable others. N-adic interactions likely also happen in other on- and offline venues in which participants are obscured but can contribute anonymously.postprin

A multi-metric approach to investigate the effects of weather conditions on the demographic of a terrestrial mammal, the European badger (Meles meles)

Models capturing the full effects of weather conditions on animal populations are scarce. Here we decompose yearly temperature and rainfall into mean trends, yearly amplitude of change and residual variation, using daily records. We establish from multi-model inference procedures, based on 1125 life histories (from 1987 to 2008), that European badger (Meles meles) annual mortality and recruitment rates respond to changes in mean trends and to variability in proximate weather components. Variation in mean rainfall was by far the most influential predictor in our analysis. Juvenile survival and recruitment rates were highest at intermediate levels of mean rainfall, whereas low adult survival rates were associated with only the driest, and not the wettest, years. Both juvenile and adult survival rates also exhibited a range of tolerance for residual standard deviation around daily predicted temperature values, beyond which survival rates declined. Life-history parameters, annual routines and adaptive behavioural responses, which define the badgers’ climatic niche, thus appear to be predicated upon a bounded range of climatic conditions, which support optimal survival and recruitment dynamics. That variability in weather conditions is influential, in combination with mean climatic trends, on the vital rates of a generalist, wide ranging and K-selected medium-sized carnivore, has major implications for evolutionary ecology and conservation

Optimal stomatal behaviour around the world

© 2015 Macmillan Publishers Limited. All rights reserved. Stomatal conductance (g s) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of g s in predictions of global water and carbon cycle changes, a global-scale database and an associated globally applicable model of g s that allow predictions of stomatal behaviour are lacking. Here, we present a database of globally distributed g s obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model and the leaf and wood economics spectrum. We also demonstrate a global relationship with climate. These findings provide a robust theoretical framework for understanding and predicting the behaviour of g s across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate