962 research outputs found

    The effects of singeing on the histological appearance of some visceral organs in the red Sokoto goat (Capra hirrcus)

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    The histology of visceral organs from singed Red Sokoto goats were assessed for reliability for use as histopathological samples from singed abattoir specimen. This becomes important as samples for histopathology and histology of goats in Nigeria have been sourced from singed carcasses, with no available literature reporting on the effect of singeing on the histological appearance of tissues from such sample. Hence, this study will fill this knowledge gap. The unfixed samples post-singeing were grouped into time periods of an hour interval up to 3 hours. They were subsequently fixed after allocated tie framed and processed for histological observation. The slides were graded on a scale of 1 to 3, where 1 referred to highly distorted, 2 referred to moderately distorted and 3 referred to mildly distorted. The samples from unsigned viscera that were fixed immediately served as control. Most of the visceral organs showed moderate distortions, except the intestines which degenerated to highly distorted architecture after 3 hours. The stomach compartments displayed normal organ structure similar to the control samples. Blood extravasations were observed in most of the organs. This project shows that samples from singed carcasses that are fixed within 2 hours post-singeing are stable for histology or histopathological studies. It also implied that abattoir samples for histopathogy should be sent to the nearest laboratory about 2 hours radius for fixation and processing to generate reliable data.Key words: Singeing, organ architecture, fixation, histology, histopathology, Nigeri

    GAUSSPY+: A fully automated Gaussian decomposition package for emission line spectra

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    Our understanding of the dynamics of the interstellar medium is informed by the study of the detailed velocity structure of emission line observations. One approach to study the velocity structure is to decompose the spectra into individual velocity components; this leads to a description of the data set that is significantly reduced in complexity. However, this decomposition requires full automation lest it become prohibitive for large data sets, such as Galactic plane surveys. We developed GAUSSPY+, a fully automated Gaussian decomposition package that can be applied to emission line data sets, especially large surveys of HI and isotopologues of CO. We built our package upon the existing GAUSSPY algorithm and significantly improved its performance for noisy data. New functionalities of GAUSSPY+ include: (i) automated preparatory steps, such as an accurate noise estimation, which can also be used as stand-alone applications; (ii) an improved fitting routine; (iii) an automated spatial refitting routine that can add spatial coherence to the decomposition results by refitting spectra based on neighbouring fit solutions. We thoroughly tested the performance of GAUSSPY+ on synthetic spectra and a test field from the Galactic Ring Survey. We found that GAUSSPY+ can deal with cases of complex emission and even low to moderate signal-to-noise values

    Antidepressants for Preventing Postnatal Depression

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    Background Depression is common in the postnatal period and can lead to adverse effects on the infant and wider family, in addition to the morbidity for the mother. It is not clear whether antidepressants are effective for the prevention of postnatal depression and little is known about possible adverse effects for the mother and infant, particularly during breastfeeding. This is an update of a Cochrane Review last published in 2005. Objectives To assess the effectiveness of antidepressant medication for the prevention of postnatal depression, in comparison with any other treatment, placebo or standard care. Search methods We searched the Cochrane Common Mental Disorders Controlled Trials Register (CCMDCTR both Studies and References), CENTRAL (Wiley), MEDLINE (OVID), Embase (OVID), PsycINFO (OVID), on 13 February 2018. We also searched the World HealthOrganization (WHO) trials portal (ICTRP) and ClinicalTrials.gov on 13 February 2018 to identify any additional unpublished or ongoing studies. Selection criteria Randomised controlled trials (RCTs) of initiation of antidepressants (alone or in combination with another treatment), compared with any other treatment, placebo or standard care for the prevention of postnatal depression among women who were either pregnant or had given birth in the previous six weeks and were not currently depressed at baseline. Data collection and analysis We used standard methodological procedures expected by Cochrane. We requested missing information from investigators wherever possible and sought data to allow intention-to-treat analyses

    The three-dimensional structure of Galactic molecular cloud complexes out to 2.5 kpc

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    Knowledge of the three-dimensional structure of Galactic molecular clouds is important for understanding how clouds are affected by processes such as turbulence and magnetic fields and how this structure effects star formation within them. Great progress has been made in this field with the arrival of the Gaia mission, which provides accurate distances to ∼109\sim10^{9} stars. Combining these distances with extinctions inferred from optical-IR, we recover the three-dimensional structure of 16 Galactic molecular cloud complexes at ∼1\sim1pc resolution using our novel three-dimensional dust mapping algorithm \texttt{Dustribution}. Using \texttt{astrodendro} we derive a catalogue of physical parameters for each complex. We recover structures with aspect ratios between 1 and 11, i.e.\ everything from near-spherical to very elongated shapes. We find a large variation in cloud environments that is not apparent when studying them in two-dimensions. For example, the nearby California and Orion A clouds look similar on-sky, but we find California to be more sheet-like, and massive, which could explain their different star-formation rates. In Carina, our most distant complex, we observe evidence for dust sputtering, which explains its measured low dust mass. By calculating the total mass of these individual clouds, we demonstrate that it is necessary to define cloud boundaries in three-dimensions in order to obtain an accurate mass; simply integrating the extinction overestimates masses. We find that Larson's relationship on mass vs radius holds true whether you assume a spherical shape for the cloud or take their true extents.Comment: accepted for publication by MNRAS, 23 pages, 9 figures, 3 table

    ALMA uncovers highly filamentary structure towards the Sgr E region

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    We report on the discovery of linear filaments observed in CO(1-0) emission for a ∼2′\sim2' field of view toward the Sgr E star forming region centered at (l,b)=(358.720∘^\circ, 0.011∘^\circ). The Sgr E region is thought to be at the turbulent intersection of the ''far dust lane'' associated with the Galactic bar and the Central Molecular Zone (CMZ). This region is subject to strong accelerations which are generally thought to inhibit star formation, yet Sgr E contains a large number of HII regions. We present 12^{12}CO(1-0), 13^{13}CO(1-0), and C18^{18}O(1-0) spectral line observations from ALMA and provide measurements of the physical and kinematic properties for two of the brightest filaments. These filaments have widths (FWHM) of ∼0.1\sim0.1 pc and are oriented nearly parallel to the Galactic plane, with angles from the Galactic plane of ∼2∘\sim2^\circ. The filaments are elongated, with lower limit aspect ratios of ∼\sim5:1. For both filaments we detect two distinct velocity components that are separated by about 15 km s−1^{-1}. In the C18^{18}O spectral line data with ∼\sim0.09 pc spatial resolution, we find that these velocity components have relatively narrow (∼\sim1-2 km s−1^{-1}) FWHM linewidths when compared to other sources towards the Galactic center. The properties of these filaments suggest that the gas in the Sgr E complex is being ''stretched'' as it is rapidly accelerated by the gravitational field of the Galactic bar while falling towards the CMZ, a result that could provide insight into the extreme environment surrounding this region and the large-scale processes which fuel this environment.Comment: 20 pages, 17 figures, accepted for publication in Ap

    Multicomponent kinematics in a massive filamentary IRDC

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    To probe the initial conditions for high-mass star and cluster formation, we investigate the properties of dense filaments within the infrared dark cloud G035.39-00.33 (IRDC G035.39) in a combined Very Large Array (VLA) and the Green Bank Telescope (GBT) mosaic tracing the NH3 (1,1) and (2,2) emission down to 0.08 pc scales. Using agglomerative hierarchical clustering on multiple line-of-sight velocity component fitting results, we identify seven extended velocity-coherent components in our data, likely representing spatially coherent physical structures, some exhibiting complex gas motions. The velocity gradient magnitude distribution peaks at its mode of 0.35 km/s/pc and has a long tail extending into higher values of 1.5 - 2 km/s/pc, and is generally consistent with those found toward the same cloud in other molecular tracers and with the values found towards nearby low-mass dense cloud cores at the same scales. Contrary to observational and theoretical expectations, we find the non-thermal ammonia line widths to be systematically narrower (by about 20%) than those of N2H+ (1-0) line transition observed with similar resolution. If the observed ordered velocity gradients represent the core envelope solid-body rotation, we estimate the specific angular momentum to be about 2 x 10^21 cm^2/s, similar to the low-mass star-forming cores. Together with the previous finding of subsonic motions in G035.39, our results demonstrate high levels of similarity between kinematics of a high-mass star-forming IRDC and the low-mass star formation regime.Comment: 22 pages, 14 figures, accepted to Ap

    'The Brick' is not a brick : A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016

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    © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.In this paper we provide a comprehensive description of the internal dynamics of G0.253+0.016 (a.k.a. 'the Brick'); one of the most massive and dense molecular clouds in the Galaxy to lack signatures of widespread star formation. As a potential host to a future generation of high-mass stars, understanding largely quiescent molecular clouds like G0.253+0.016 is of critical importance. In this paper, we reanalyse Atacama Large Millimeter Array cycle 0 HNCO J=4(0,4)−3(0,3)J=4(0,4)-3(0,3) data at 3 mm, using two new pieces of software which we make available to the community. First, scousepy, a Python implementation of the spectral line fitting algorithm scouse. Secondly, acorns (Agglomerative Clustering for ORganising Nested Structures), a hierarchical n-dimensional clustering algorithm designed for use with discrete spectroscopic data. Together, these tools provide an unbiased measurement of the line of sight velocity dispersion in this cloud, σvlos,1D=4.4±2.1\sigma_{v_{los}, {\rm 1D}}=4.4\pm2.1 kms−1^{-1}, which is somewhat larger than predicted by velocity dispersion-size relations for the Central Molecular Zone (CMZ). The dispersion of centroid velocities in the plane of the sky are comparable, yielding σvlos,1D/σvpos,1D∼1.2±0.3\sigma_{v_{los}, {\rm 1D}}/\sigma_{v_{pos}, {\rm 1D}}\sim1.2\pm0.3. This isotropy may indicate that the line-of-sight extent of the cloud is approximately equivalent to that in the plane of the sky. Combining our kinematic decomposition with radiative transfer modelling we conclude that G0.253+0.016 is not a single, coherent, and centrally-condensed molecular cloud; 'the Brick' is not a \emph{brick}. Instead, G0.253+0.016 is a dynamically complex and hierarchically-structured molecular cloud whose morphology is consistent with the influence of the orbital dynamics and shear in the CMZ.Peer reviewedFinal Accepted Versio

    Quantum Electronics

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    Contains research objectives and summary of research on eight projects in three sections and reports on two research projects.U. S. Air Force - Office of Scientific Research (Contract F44620-71-C-0051)Joint Services Electronics Program (Contract DAAB07-74-C-0630)University of California, Livermore (Subcontract No. 7877409)U. S. Army Research Office - Durham (Contract DAHC04-72-C-0044

    JWST reveals widespread CO ice and gas absorption in the Galactic Center cloud G0.253+0.016

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    We report JWST NIRCam observations of G0.253+0.016, the molecular cloud in the Central Molecular Zone known as The Brick, with the F182M, F187N, F212N, F410M, F405N, and F466N filters. We catalog 56,146 stars detected in all 6 filters using the crowdsource package. Stars within and behind The Brick exhibit prodigious absorption in the F466N filter that is produced by a combination of CO ice and gas. In support of this conclusion, and as a general resource, we present models of CO gas and ice and CO2_2 ice in the F466N, F470N, and F410M filters. Both CO gas and ice may contribute to the observed stellar colors. We show, however, that CO gas does not absorb the Pfβ\beta and Huϵ\epsilon lines in F466N, but that these lines show excess absorption, indicating that CO ice is also present and contributes to observed F466N absorption. The most strongly absorbed stars in F466N are extincted by ∼\sim 2 magnitudes, corresponding to >> 80\% flux loss. This high observed absorption requires very high column densities of CO, requiring total CO column that is in tension with standard CO abundance and/or gas-to-dust ratios. There is therefore likely to be a greater CO/H2_2 ratio (XCO>10−4_{CO} > 10^{-4}) and more dust per H2_2 molecule (>0.01>0.01) in the Galactic Center than the Galactic disk. Ice and/or gas absorption is observed even in the cloud outskirts, implying that additional caution is needed when interpreting stellar photometry in filters that overlap with ice bands throughout our Galactic Center. The widespread CO absorption in our Galactic Center hints that significant ice absorption is likely present in other galactic centers.Comment: Submitted to ApJ. Revised after second referee report. 16 pages, 11 figure

    Scenario-based design and evaluation for capability

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    Scenarios are frequently used within techniques for planning and designing systems. They are an especially helpful means of visualizing and understanding the incorporation of new systems within systems of systems. If used as the basis for decisions about candidate designs, then it is important that such decisions can be rationalized and quantitative assessment is particularly important. In this paper, an approach for developing complex scenarios, which incorporates the phases of systems development and deployment, is presented and a quantitative method of comparison is described. This approach is based on the development of measures of merit and measures of performance. The techniques are illustrated using cases that are relevant to Network Enabled Capability
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