1,130 research outputs found
Unusual manifestations of secondary urothelial carcinoma
AbstractHigh-grade papillary urothelial carcinoma regularly invades the bladder wall, adjacent prostate, seminal vesicles, ureters, vagina, rectum, retroperitoneum, and regional lymph nodes. In advanced stages, it may disseminate to the liver, lungs, and bone marrow. On rare occasions, unusual metastatic foci like skin have been reported. The incidence of urothelial carcinoma has increased with associated rise in variants of urothelial carcinoma and unusual metastatic foci. It is imperative that urologists and pathologists are aware of the unusual variants and unusual metastatic locations to expedite the diagnostic process. Hereby we report an unusual case of secondary involvement of spinal nerve by conventional urothelial carcinoma. Also a second case of rhabdoid variant of urothelial carcinoma showing synchronous involvement of bladder and subcutaneous tissue of upper extremity is presented
High Temperature Photochemistry in the Atmosphere of HD189733b
Recent infrared spectroscopy of hot exoplanets is beginning to reveal their
atmospheric composition. Deep with in the planetary atmosphere, the composition
is controlled by thermochemical equilibrium. Photochemistry becomes important
higher in the atmosphere, at levels above ~1 bar. These two chemistries compete
between ~1-10 bars in hot Jupiter-like atmospheres, depending on the strength
of the eddy mixing and temperature. HD189733b provides an excellent laboratory
in which to study the consequences of chemistry of hot atmospheres. The recent
spectra of HD189733b and HD209458b contain signatures of CH4, CO2, CO and H2O.
Here we identify the primary chemical pathways that govern the abundances of
CH4, CO2, CO and H2O in the cases of thermochemical equilibrium chemistry,
photochemistry, and their combination. Our results suggest that the abundance
of these species can be photochemically enhanced above or below the
thermochemical equilibrium value, so some caution must be taken when assuming
that an atmosphere is in strict thermochemical equilibrium
Properties of nitrogen-vacancy centers in diamond: group theoretic approach
We present a procedure that makes use of group theory to analyze and predict
the main properties of the negatively charged nitrogen-vacancy (NV) center in
diamond. We focus on the relatively low temperatures limit where both the
spin-spin and spin-orbit effects are important to consider. We demonstrate that
group theory may be used to clarify several aspects of the NV structure, such
as ordering of the singlets in the () electronic configuration, the
spin-spin and the spin-orbit interactions in the () electronic
configuration. We also discuss how the optical selection rules and the response
of the center to electric field can be used for spin-photon entanglement
schemes. Our general formalism is applicable to a broad class of local defects
in solids. The present results have important implications for applications in
quantum information science and nanomagnetometry.Comment: 30 pages, 6 figure
Imitation, mirror neurons and autism
Various deficits in the cognitive functioning of people with autism have been documented in recent years but these provide only partial explanations for the condition. We focus instead on an imitative disturbance involving difficulties both in copying actions and in inhibiting more stereotyped mimicking, such as echolalia. A candidate for the neural basis of this disturbance may be found in a recently discovered class of neurons in frontal cortex, 'mirror neurons' (MNs). These neurons show activity in relation both to specific actions performed by self and matching actions performed by others, providing a potential bridge between minds. MN systems exist in primates without imitative and ‘theory of mind’ abilities and we suggest that in order for them to have become utilized to perform social cognitive functions, sophisticated cortical neuronal systems have evolved in which MNs function as key elements. Early developmental failures of MN systems are likely to result in a consequent cascade of developmental impairments characterised by the clinical syndrome of autism
High Metallicity and Non-equilibrium Chemistry in the Dayside Atmosphere of hot-Neptune GJ 436b
We present a detailed analysis of the dayside atmosphere of the hot-Neptune
GJ~436b, based on recent Spitzer observations. We report statistical
constraints on the thermal and chemical properties of the planetary atmosphere,
study correlations between the various molecular species, and discuss scenarios
of equilibrium and non-equilibrium chemistry in GJ 436b. We model the
atmosphere with a one-dimensional line-by-line radiative transfer code with
parameterized molecular abundances and temperature structure. We explore the
model parameter space with 10^6 models, using a Markov chain Monte Carlo
scheme. Our results encompass previous findings, indicating a paucity of
methane, an overabundance of CO and CO2, and a slight underabundance of H2O, as
compared to equilibrium chemistry with solar metallicity. The concentrations of
the species are highly correlated. Our best-fit, and most plausible,
constraints require a CH4 mixing ratio of 1.0E-7 to 1.0E-6, with CO >= 1.0E-3,
CO2 ~ 1.0E-6 to 1.0E-4, and H2O <= 1.0E-4; higher CH4 would require much higher
CO and CO2. Based on calculations of equilibrium and non-equilibrium chemistry,
we find that the observed abundances can potentially be explained by a
combination of high metallicity (~ 10 x solar) and vertical mixing with Kzz ~
10^6 - 10^7 cm^2/s. The inferred metallicity is enhanced over that of the host
star which is known to be consistent with solar metallicity. Our constraints
rule out a dayside thermal inversion in GJ 436b. We emphasize that the
constraints reported in this work depend crucially on the observations in the
two Spitzer channels at 3.6 micron and 4.5 micron. Future observations with
warm Spitzer and with the James Webb Space Telescope will be extremely
important to improve upon the present constraints on the abundances of carbon
species in the dayside atmosphere of GJ 436b.Comment: Accepted version, 15 pages in emulateapj, 7 figures. Published in
ApJ, 2011, 729, 4
Q methodology and a Delphi poll: a useful approach to researching a narrative approach to therapy
Q methodology and a Delphi poll combined qualitative and quantitative methods to explore definitions of White and Epston's (1990) narrative approach to therapy among a group of UK practitioners. A Delphi poll was used to generate statements about narrative therapy. The piloting of statements by the Delphi panel identified agreement about theoretical ideas underpinning narrative therapy and certain key practices. A wider group of practitioners ranked the statements in a Q sort and made qualitative comments about their sorting. Quantitative methods (principal components analysis) were used to extract eight accounts of narrative therapy, five of which are qualitatively analysed in this paper. Agreement and differences were identified across a range of issues, including the social construction of narratives, privileging a political stance or narrative techniques and the relationship with other therapies, specifically systemic psychotherapy. Q methodology, combined with the Delphi poll, was a unique and innovative feature of this study
Climatic controls on the global distribution, abundance, and species richness of mangrove forests
Mangrove forests are highly productive tidal saline wetland ecosystems found along sheltered tropical and subtropical coasts. Ecologists have long assumed that climatic drivers (i.e., temperature and rainfall regimes) govern the global distribution, structure, and function of mangrove forests. However, data constraints have hindered the quantification of direct climate-mangrove linkages in many parts of the world. Recently, the quality and availability of global-scale climate and mangrove data have been improving. Here, we used these data to better understand the influence of air temperature and rainfall regimes upon the distribution, abundance, and species richness of mangrove forests. Although our analyses identify global-scale relationships and thresholds, we show that the influence of climatic drivers is best characterized via regional range-limit-specific analyses. We quantified climatic controls across targeted gradients in temperature and/or rainfall within 14 mangrove distributional range limits. Climatic thresholds for mangrove presence, abundance, and species richness differed among the 14 studied range limits. We identified minimum temperature-based thresholds for range limits in eastern North America, eastern Australia, New Zealand, eastern Asia, eastern South America, and southeast Africa. We identified rainfall-based thresholds for range limits in western North America, western Gulf of Mexico, western South America, western Australia, Middle East, northwest Africa, east central Africa, and west-central Africa. Our results show that in certain range limits (e.g., eastern North America, western Gulf of Mexico, eastern Asia), winter air temperature extremes play an especially important role. We conclude that rainfall and temperature regimes are both important in western North America, western Gulf of Mexico, and western Australia. With climate change, alterations in temperature and rainfall regimes will affect the global distribution, abundance, and diversity of mangrove forests. In general, warmer winter temperatures are expected to allow mangroves to expand poleward at the expense of salt marshes. However, dispersal and habitat availability constraints may hinder expansion near certain range limits. Along arid and semiarid coasts, decreases or increases in rainfall are expected to lead to mangrove contraction or expansion, respectively. Collectively, our analyses quantify climate-mangrove linkages and improve our understanding of the expected global- and regional-scale effects of climate change upon mangrove forests
Understanding Behavioral Sources of Process Variation Following Enterprise System Deployment
This paper extends the current understanding of the time-sensitivity of intent and usage following large-scale IT implementation. Our study focuses on perceived system misfit with organizational processes in tandem with the availability of system circumvention opportunities. Case study comparisons and controlled experiments are used to support the theoretical unpacking of organizational and technical contingencies and their relationship to shifts in user intentions and variation in work-processing tactics over time. Findings suggest that managers and users may retain strong intentions to circumvent systems in the presence of perceived task-technology misfit. The perceived ease with which this circumvention is attainable factors significantly into the timeframe within which it is attempted, and subsequently impacts the onset of deviation from prescribed practice and anticipated dynamics
Linear and nonlinear effects of temperature and precipitation on ecosystem properties in tidal saline wetlands
Climate greatly influences the structure and functioning of tidal saline wetland ecosystems. However, there is a need to better quantify the effects of climatic drivers on ecosystem properties, particularly near climate-sensitive ecological transition zones. Here, we used climate- and literature-derived ecological data from tidal saline wetlands to test hypotheses regarding the influence of climatic drivers (i.e., temperature and precipitation regimes) on the following six ecosystem properties: canopy height, biomass, productivity, decomposition, soil carbon density, and soil carbon accumulation. Our analyses quantify and elucidate linear and nonlinear effects of climatic drivers. We quantified positive linear relationships between temperature and above-ground productivity and strong positive nonlinear (sigmoidal) relationships between (1) temperature and above-ground biomass and canopy height and (2) precipitation and canopy height. Near temperature-controlled mangrove range limits, small changes in temperature are expected to trigger comparatively large changes in biomass and canopy height, as mangrove forests grow, expand, and, in some cases, replace salt marshes. However, within these same transition zones, temperature- induced changes in productivity are expected to be comparatively small. Interestingly, despite the significant above-ground height, biomass, and productivity relationships across the tropical–temperate mangrove–marsh transition zone, the relationships between temperature and soil carbon density or soil carbon accumulation were not significant. Our literature review identifies several ecosystem properties and many regions of the world for which there are insufficient data to fully evaluate the influence of climatic drivers, and the identified data gaps can be used by scientists to guide future research. Our analyses indicate that near precipitation-controlled transition zones, small changes in precipitation are expected to trigger comparatively large changes in canopy height. However, there are scant data to evaluate the influence of precipitation on other ecosystem properties. There is a need for more decomposition data across climatic gradients, and to advance understanding of the influence of changes in precipitation and freshwater availability, additional ecological data are needed from tidal saline wetlands in arid climates. Collectively, our results can help scientists and managers better anticipate the linear and nonlinear ecological consequences of climate change for coastal wetlands
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