1,076 research outputs found
Three-dimensional geometric morphometrics for studying floral shape variation
Variation in floral shape is of major interest to evolutionary and pollination biologists, plant systematists and developmental geneticists. Quantifying this variation has been difficult due to the three-dimensional (3D) complexity of angiosperm flowers. By combining 3D geometric representations of flowers obtained by micro-computed tomography scanning with geometric morphometric methods, well established in zoology and anthropology, floral shape variation can be analyzed quantitatively, allowing for powerful interpretation and visualization of the resulting patterns of variation
Huge carotid body paraganglioma
A 33-year-old woman was admitted to our hospital with a slow-growing mass in the left side of her neck. The mass was found to be a huge (73 × 56 × 54 mm) carotid body paraganglioma. Another 21 mm-size tumor was incidentally detected at the right carotid bifurcation. She had hoarseness and Horner's syndrome of her left side. Both tumors were surgically removed. There were no cerebrovascular complications but some neurologic complications occurred when the left tumor was removed
Comparing Galaxies and Lyman Alpha Absorbers at Low Redshift
A scenario is explored in which Lyman alpha absorbers at low redshift arise
from lines of sight through extended galaxy disks, including those of dwarf and
low surface brightness galaxies. A population of galaxies is simulated based
upon observed distributions of galaxy properties, and the gas disks are modeled
using pressure and gravity confinement. Some parameter values are ruled out by
comparing simulation results with the observed galaxy luminosity function, and
constraints may be made on the absorbing cross sections of galaxies. Simulation
results indicate that it is difficult to match absorbers with particular
galaxies observationally since absorption typically occurs at high impact
parameters (>200 kpc) from luminous galaxies. Low impact parameter absorption
is dominated by low luminosity dwarfs. A large fraction of absorption lines is
found to originate from low surface brightness galaxies, so that the absorbing
galaxy is likely to be misidentified. Low redshift Lyman alpha absorber counts
can easily be explained by moderately extended galaxy disks when low surface
brightness galaxies are included, and it is easily possible to find a scenario
which is consistent with observed the galaxy luminosity function, with low
redshift Lyman limit absorber counts, and with standard nucleosynthesis
predictions of the baryon density, Omega_Baryon.Comment: 17 pages, 8 figures, accepted to the Astrophysical Journa
3D models of radiatively driven colliding winds in massive O+O star binaries - II. Thermal radio to sub-mm emission
In this work the thermal emission over cm to sub-mm wavelengths from the
winds in short-period O+O-star binaries is investigated (potential non-thermal
emission is presently ignored). The calculations are based on three-dimensional
hydrodynamical models which incorporate gravity, the driving of the winds,
orbital motion of the stars, and radiative cooling of the shocked plasma. The
thermal emission arises from the stellar winds and the region where they
collide. We investigate the flux and spectrum from a variety of models as a
function of orbital phase and orientation of the observer, and compare to the
single star case. The emission from the wind-wind collision region (WCR) is
strongly dependent on its density and temperature, being optically thick in
radiative systems, and optically thin in adiabatic systems. The flux from
systems where the WCR is highly radiative, as investigated for the first time
in this work, can be over an order of magnitude greater than the combined flux
from identically typed single stars. This excess occurs over a broad range of
wavelengths from cm to sub-mm. In contrast, when the WCR is largely adiabatic,
a significant excess in the thermal flux occurs only below 100 GHz. Eccentric
systems may show order of magnitude or greater flux variability, especially if
the plasma in the WCR transitions from an adiabatic to a radiative state and
vice-versa - in such cases the flux can display significant hysteresis with
stellar separation. We further demonstrate that clumping can affect the
variability of radio lightcurves. We investigate the spectral index of the
emission, and often find indices steeper than +0.6. Our predictions are of
interest to future observations with the next generation of radio and sub-mm
telescopes (abridged).Comment: 25 pages, 21 figures, accepted for publication in MNRA
Coral reef fish assemblages at Clipperton Atoll (Eastern Tropical Pacific) and their relationship with coral cover
Clipperton Atoll, one of the most isolated coral reefs worldwide, is of great scientific interest due to its geomorphology and high levels of endemism. This study explored the reef fish assemblage structure of Clipperton Atoll and its relationship with live coral cover. Nine stations were sampled at three sites and three depths (6, 12 and 20 m) around the reef, measuring fish species richness and biomass and hermatypic coral cover (at genus level). We evaluated variation in species richness, biomass and diversity of fish assemblages among sites and depths, as well as the relationship between the entire fish assemblage composition and live coral cover. The results showed that species richness and biomass were similar among sites, but differed across depths, increasing with depth. In contrast, diversity differed among sites but not among depths. Multivariate analyses indicated that fish assemblage composition differed among sites and depths in relation to changes in cover of coral of the genera Pocillopora, Porites, Pavona and Leptoseris, which dominate at different depths. The results showed that fish species richness and diversity were low at Clipperton Atoll and that, in isolated coral reefs with a low habitat heterogeneity and low human disturbance, live coral cover has a significant influence on the spatial variation of the reef fish assemblages. This study highlights the importance of coral habitat structure in shaping coral reef fish assemblages
Hot stars observed by XMM-Newton I. The catalog and the properties of OB stars
Aims : Following the advent of increasingly sensitive X-ray observatories,
deep observations of early-type stars became possible. However, the results for
only a few objects or clusters have until now been reported and there has been
no large survey comparable to that based upon the ROSAT All-Sky Survey (RASS).
Methods : A limited survey of X-ray sources, consisting of all public XMM
observations (2XMMi) and slew survey data (XMMSL1), is now available. The X-ray
counterparts to hot, massive stars have been searched for in these catalogs.
Results : About 300 OB stars were detected with XMM. Half of them were bright
enough for a spectral analysis to be possible, and we make available the
detailed spectral properties that were derived. The X-ray spectra of O stars
are represented well by low (<1keV) temperature components and seem to indicate
that an absorption column is present in addition to the interstellar
contribution. The X-ray fluxes are well correlated with the bolometric fluxes,
with a scatter comparable to that of the RASS studies and thus larger than
found previously with XMM for some individual clusters. These results contrast
with those of B stars that exhibit a large scatter in the L_X-L_BOL relation,
no additional absorption being found, and the fits indicate a plasma at higher
temperatures. Variability (either within one exposure or between multiple
exposures) was also investigated whenever possible: short-term variations are
far more rare than long-term ones (the former affects a few percent of the
sample, while the latter concerns between one third and two thirds of the
sources). Conclusions : This paper presents the results of the first
high-sensitivity investigation of the overall high-energy properties of a
sizable sample of hot stars.Comment: 10 pages, 4 figures, accepted for publication by A&
Формування передумов соціально-політичних конфліктів в українському суспільстві періоду трансформації
У статті на основі емпіричних показників всеукраїнського моніторингового дослідження, проведеного в 1994-2004 рр. Інститутом соціології НАН України з’ясовуються і аналізуються групи факторів, що детермінували появу соціально-політичних конфліктів в сучасному українському суспільстві, зумовили їх природу та характер розвитку.The article empirical indicators nationwide monitoring study conducted in 1994-2004 in the Institute of Sociology of NAS of Ukraine researched and analyzed a group of factors that determinuvaly emergence of socio-political conflicts in modern Ukrainian society, led to their nature and character development
Two subphenotypes of septic acute kidney injury are associated with different 90-day mortality and renal recovery
Background The pathophysiology of septic acute kidney injury is inadequately understood. Recently, subphenotypes for sepsis and AKI have been derived. The objective of this study was to assess whether a combination of comorbidities, baseline clinical data, and biomarkers could classify meaningful subphenotypes in septic AKI with different outcomes. Methods We performed a post hoc analysis of the prospective Finnish Acute Kidney Injury (FINNAKI) study cohort. We included patients admitted with sepsis and acute kidney injury during the first 48 h from admission to intensive care (according to Kidney Disease Improving Global Outcome criteria). Primary outcomes were 90-day mortality and renal recovery on day 5. We performed latent class analysis using 30 variables obtained on admission to classify subphenotypes. Second, we used logistic regression to assess the association of derived subphenotypes with 90-day mortality and renal recovery on day 5. Results In total, 301 patients with septic acute kidney injury were included. Based on the latent class analysis, a two-class model was chosen. Subphenotype 1 was assigned to 133 patients (44%) and subphenotype 2 to 168 patients (56%). Increased levels of inflammatory and endothelial injury markers characterized subphenotype 2. At 90 days, 29% of patients in subphenotype 1 and 41% of patients in subphenotype 2 had died. Subphenotype 2 was associated with a lower probability of short-term renal recovery and increased 90-day mortality. Conclusions In this post hoc analysis, we identified two subphenotypes of septic acute kidney injury with different clinical outcomes. Future studies are warranted to validate the suggested subphenotypes of septic acute kidney injury.Peer reviewe
Rhodococcus equi Infection after Alemtuzumab Therapy for T-cell Prolymphocytic Leukemia
Rhodococcus equi, mainly known from veterinary medicine as a pathogen in domestic animals, can also cause infections in immunocompromised humans, especially in those with defects in cellular immunity. Alemtuzumab, an anti-CD52 monoclonal antibody, causes lymphocytopenia by eliminating CD52-positive cells. We report a patient in whom Rhodococcus equi infection developed after alemtuzumab therapy
Compressed air energy storage with liquid air capacity extension
As renewable electricity generation capacity increases, energy storage will be required at larger scales. Compressed Air Energy Storage (CAES) at large scales, with effective management of heat, is recognised to have potential to provide affordable grid-scale energy storage. Where suitable geologies are unavailable, compressed air could be stored in pressurised steel tanks above ground, but this would incur significant storage costs. Liquid Air Energy Storage (LAES), on the other hand, does not need a pressurised storage vessel, can be located almost anywhere, has a relatively large volumetric exergy density at ambient pressure, and has relatively low marginal cost of energy storage capacity even at modest scales. However, it has lower roundtrip efficiency than compressed air energy storage technologies. This paper carries out thermodynamic analyses for an energy storage installation comprising a compressed air component supplemented with a liquid air store, and additional machinery to transform between gaseous air at ambient temperature and high pressure, and liquid air at ambient pressure. A roundtrip efficiency of 42% is obtained for the conversion of compressed air at 50 bar to liquid air, and back. The proposed system is more economical than pure LAES and more economical than a pure CAES installation if the storage duration is sufficiently long and if the high-pressure air store cannot exploit some large-scale geological feature
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