161 research outputs found
Biochemical Profile of Amniotic and Allantoic Fluid During Different Gestational Phases in Mares
AbstractFetal fluids have different vital functions that sustain both pregnancy and normal parturition. The biochemical composition of amniotic fluid during gestation is not well established; thus the purpose of the present study was to determine the biochemical profile of both amniotic and allantoic fluids from mares during initial, mid, and latter third phases of pregnancy. Samples were collected after slaughter, using allantocentesis and amniocentesis. Sixty samples of fetal fluids were analyzed. Alkaline phosphatase (AP), glucose, total protein (TP), urea, creatinine, Ca, chloride (Cl), Na, and K concentrations were measured using commercially available kits. The AP concentration in amniotic fluid was higher than that in allantoic fluid during the three gestational phases (P < .05). There were no differences between glucose mean values of allantoic and those of amniotic fluids (P < .05). However, glucose values were higher in the allantoic fluid in the last trimester of pregnancy. TP was higher in the amniotic fluid than in allantoic fluid (P < .05). Urea values varied among the phases; however, there were no differences between the amniotic and allantoic fluid values (P > .05). Creatinine values were higher in allantoic fluid (P < .05). Na and Cl concentrations were higher in amniotic fluid (P < .05). However, Ca and K concentrations were higher in the allantoic fluid
Investigation of transition frequencies of two acoustically coupled bubbles using a direct numerical simulation technique
The theoretical results regarding the ``transition frequencies'' of two
acoustically interacting bubbles have been verified numerically. The theory
provided by Ida [Phys. Lett. A 297 (2002) 210] predicted the existence of three
transition frequencies per bubble, each of which has the phase difference of
between a bubble's pulsation and the external sound field, while
previous theories predicted only two natural frequencies which cause such phase
shifts. Namely, two of the three transition frequencies correspond to the
natural frequencies, while the remaining does not. In a subsequent paper [M.
Ida, Phys. Rev. E 67 (2003) 056617], it was shown theoretically that transition
frequencies other than the natural frequencies may cause the sign reversal of
the secondary Bjerknes force acting between pulsating bubbles. In the present
study, we employ a direct numerical simulation technique that uses the
compressible Navier-Stokes equations with a surface-tension term as the
governing equations to investigate the transition frequencies of two coupled
bubbles by observing their pulsation amplitudes and directions of translational
motion, both of which change as the driving frequency changes. The numerical
results reproduce the recent theoretical predictions, validating the existence
of the transition frequencies not corresponding to the natural frequency.Comment: 18 pages, 8 figures, in pres
Isolating signatures of major cloud-cloud collisions - II. The lifetimes of broad bridge features
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.We investigate the longevity of broad bridge features in position–velocity diagrams that appear as a result of cloud–cloud collisions. Broad bridges will have a finite lifetime due to the action of feedback, conversion of gas into stars and the time-scale of the collision. We make a series of analytic arguments with which to estimate these lifetimes. Our simple analytic arguments suggest that for collisions between clouds larger than R ∼ 10 pc the lifetime of the broad bridge is more likely to be determined by the lifetime of the collision rather than the radiative or wind feedback disruption time-scale. However, for smaller clouds feedback becomes much more effective. This is because the radiative feedback time-scale scales with the ionizing flux Nly as R7/4N−1/4ly R7/4Nly−1/4 so a reduction in cloud size requires a relatively large decrease in ionizing photons to maintain a given time-scale. We find that our analytic arguments are consistent with new synthetic observations of numerical simulations of cloud–cloud collisions (including star formation and radiative feedback). We also argue that if the number of observable broad bridges remains ∼ constant, then the disruption time-scale must be roughly equivalent to the collision rate. If this is the case, our analytic arguments also provide collision rate estimates, which we find are readily consistent with previous theoretical models at the scales they consider (clouds larger than about 10 pc) but are much higher for smaller clouds.Peer reviewe
Isolating signatures of major cloud-cloud collisions using position-velocity diagrams
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.Collisions between giant molecular clouds are a potential mechanism for triggering the formation of massive stars, or even super star clusters. The trouble is identifying this process observationally and distinguishing it from other mechanisms. We produce synthetic position–velocity diagrams from models of cloud–cloud collisions, non-interacting clouds along the line of sight, clouds with internal radiative feedback and a more complex cloud evolving in a galactic disc, to try and identify unique signatures of collision. We find that a broad bridge feature connecting two intensity peaks, spatially correlated but separated in velocity, is a signature of a high-velocity cloud–cloud collision. We show that the broad bridge feature is resilient to the effects of radiative feedback, at least to around 2.5 Myr after the formation of the first massive (ionizing) star. However for a head-on 10 km s−1 collision, we find that this will only be observable from 20 to 30 per cent of viewing angles. Such broad–bridge features have been identified towards M20, a very young region of massive star formation that was concluded to be a site of cloud–cloud collision by Torii et al., and also towards star formation in the outer Milky Way by Izumi et al.Peer reviewe
Linfoma multicêntrico com metástase no sistema nervoso central em cão. Relato de caso
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Search for astronomical neutrinos from blazar TXS 0506+056 in super-kamiokande
We report a search for astronomical neutrinos in the energy region from several GeV to TeV in the direction of the blazar TXS 0506+056 using the Super-Kamiokande detector following the detection of a 100 TeV neutrinos from the same location by the IceCube collaboration. Using Super-Kamiokande neutrino data across several data samples observed from 1996 April to 2018 February we have searched for both a total excess above known backgrounds across the entire period as well as localized excesses on smaller timescales in that interval. No significant excess nor significant variation in the observed event rate are found in the blazar direction. Upper limits are placed on the electron- and muon-neutrino fluxes at the 90% confidence level as 6.0 × 10−7 and 4.5 × 10−7–9.3 × 10−10 [erg cm−2 s−1], respectively
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Consensus Statement on the Pathology of IgG4-Related Disease
IgG4-related disease is a newly recognized fibro-inflammatory condition characterized by several features: a tendency to form tumefactive lesions in multiple sites; a characteristic histopathological appearance; and—often but not always—elevated serum IgG4 concentrations. An international symposium on IgG4-related disease was held in Boston, MA, on 4–7 October 2011. The organizing committee comprising 35 IgG4-related disease experts from Japan, Korea, Hong Kong, the United Kingdom, Germany, Italy, Holland, Canada, and the United States, including the clinicians, pathologists, radiologists, and basic scientists. This group represents broad subspecialty expertise in pathology, rheumatology, gastroenterology, allergy, immunology, nephrology, pulmonary medicine, oncology, ophthalmology, and surgery. The histopathology of IgG4-related disease was a specific focus of the international symposium. The primary purpose of this statement is to provide practicing pathologists with a set of guidelines for the diagnosis of IgG4-related disease. The diagnosis of IgG4-related disease rests on the combined presence of the characteristic histopathological appearance and increased numbers of IgG4+ plasma cells. The critical histopathological features are a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. We propose a terminology scheme for the diagnosis of IgG4-related disease that is based primarily on the morphological appearance on biopsy. Tissue IgG4 counts and IgG4:IgG ratios are secondary in importance. The guidelines proposed in this statement do not supplant careful clinicopathological correlation and sound clinical judgment. As the spectrum of this disease continues to expand, we advocate the use of strict criteria for accepting newly proposed entities or sites as components of the IgG4-related disease spectrum
GMC Collisions as Triggers of Star Formation. III. Density and Magnetically Regulated Star Formation
We study giant molecular cloud (GMC) collisions and their ability to trigger star cluster formation. We further develop our three dimensional magnetized, turbulent, colliding GMC simulations by implementing star formation sub-grid models. Two such models are explored: (1) Density-Regulated, i.e., fixed efficiency per free-fall time above a set density threshold; (2) Magnetically- Regulated, i.e., fixed efficiency per free-fall time in regions that are magnetically supercritical. Variations of parameters associated with these models are also explored. In the non-colliding simulations, the overall level of star formation is sensitive to model parameter choices that relate to effective density thresholds. In the GMC collision simulations, the final star formation rates and efficiencies are relatively independent of these parameters. Between non-colliding and colliding cases, we compare the morphologies of the resulting star clusters, properties of star-forming gas, time evolution of the star formation rate (SFR), spatial clustering of the stars, and resulting kinematics of the stars in comparison to the natal gas. We find that typical collisions, by creating larger amounts of dense gas, trigger earlier and enhanced star formation, resulting in 10 times higher SFRs and efficiencies. The star clusters formed from GMC collisions show greater spatial sub-structure and more disturbed kinematics
GMC Collisions as Triggers of Star Formation. II. 3D Turbulent, Magnetized Simulations
We investigate giant molecular cloud (GMCs) collisions and their ability to induce gravitational instability and thus star formation. This mechanism may be a major driver of star formation activity in galactic disks. We carry out a series of three dimensional, magnetohydrodynamics (MHD), adaptive mesh refinement (AMR) simulations to study how cloud collisions trigger formation of dense filaments and clumps. Heating and cooling functions are implemented based on photo-dissociation region (PDR) models that span the atomic to molecular transition and can return detailed diagnostic information. The clouds are initialized with supersonic turbulence and a range of magnetic field strengths and orientations. Collisions at various velocities and impact parameters are investigated. Comparing and contrasting colliding and non-colliding cases, we characterize morphologies of dense gas, magnetic field structure, cloud kinematic signatures, and cloud dynamics. We present key observational diagnostics of cloud collisions, especially: relative orientations between magnetic fields and density structures, like filaments; 13CO(J=2-1), 13CO(J=3-2), and 12CO(J=8-7) integrated intensity maps and spectra; and cloud virial parameters. We compare these results to observed Galactic clouds
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