501 research outputs found

    Consumption of Whole Cottonseed by White-Tailed Deer and Nontarget Species

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    Supplementing diets of white-tailed deer (Odocoileus virginianus) with pelleted rations is an increasingly common practice aimed at increasing deer antler size on rangelands in Texas. Feed loss to consumption by various nontarget species (e.g., raccoons [Procyon lotor] and feral pigs [Sus scrofa]) raises both ecological and economic concerns. Whole cottonseed is a feedstuff that may afford a more targeted supplemental feeding effort. Accordingly, we determined: (1) consumption rates of whole cottonseed by feral pigs and raccoons in captivity; and (2) species visitation at feed sites and preference for whole cottonseed relative to whole corn under field conditions. For experiments 1 and 2, we trapped subadult feral pigs and raccoons (n = 16 for each) and randomly assigned them to 4 feed treatments. We weighed and took blood to assess gossypol levels from both pigs and raccoons every 2 weeks for 2 months. Pigs were adept at sorting cottonseed from their feed ration in the laboratory trial. Raccoons consumed cottonseed only under severe dietary stress (i.e., diets reduced to 60% of maintenance requirements). To supplement laboratory findings we used motion-triggered video camera systems to monitor species visitation and feeding behaviors in the field. Video surveillance (125 hours of recorded events) of feeders supported our observations from laboratory trials that cottonseed was unpalatable to feral pigs and raccoons, whereas white-tailed deer consumed cottonseed readily. Given our results, we believe that whole cottonseed merits further consideration as a supplement for free-ranging deer

    Teaching Psychological Principles to Cybersecurity Students

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    This paper will discuss our observations gained from teaching psychological principles and methods to undergraduate and postgraduate cybersecurity students. We will draw on and extend our previous work encouraging the teaching of psychology in computing and cybersecurity education. We pay special attention to the consideration of characteristics of cybersecurity students in terms of teaching psychology in a way that will be accessible and engaging. We then discuss the development and use of an online training tool which draws on psychology to help educators and companies to raise awareness of cybersecurity risks in students and employees. Finally, we offer some practical suggestions to incorporate psychology into the cybersecurity curriculum

    Structural and functional conservation of key domains in InsP3 and ryanodine receptors.

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    Inositol-1,4,5-trisphosphate receptors (InsP(3)Rs) and ryanodine receptors (RyRs) are tetrameric intracellular Ca(2+) channels. In each of these receptor families, the pore, which is formed by carboxy-terminal transmembrane domains, is regulated by signals that are detected by large cytosolic structures. InsP(3)R gating is initiated by InsP(3) binding to the InsP(3)-binding core (IBC, residues 224-604 of InsP(3)R1) and it requires the suppressor domain (SD, residues 1-223 of InsP(3)R1). Here we present structures of the amino-terminal region (NT, residues 1-604) of rat InsP(3)R1 with (3.6 Å) and without (3.0 Å) InsP(3) bound. The arrangement of the three NT domains, SD, IBC-β and IBC-α, identifies two discrete interfaces (α and β) between the IBC and SD. Similar interfaces occur between equivalent domains (A, B and C) in RyR1 (ref. 9). The orientations of the three domains when docked into a tetrameric structure of InsP(3)R and of the ABC domains docked into RyR are remarkably similar. The importance of the α-interface for activation of InsP(3)R and RyR is confirmed by mutagenesis and, for RyR, by disease-causing mutations. Binding of InsP(3) causes partial closure of the clam-like IBC, disrupting the β-interface and pulling the SD towards the IBC. This reorients an exposed SD loop ('hotspot' (HS) loop) that is essential for InsP(3)R activation. The loop is conserved in RyR and includes mutations that are associated with malignant hyperthermia and central core disease. The HS loop interacts with an adjacent NT, suggesting that activation re-arranges inter-subunit interactions. The A domain of RyR functionally replaced the SD in full-length InsP(3)R, and an InsP(3)R in which its C-terminal transmembrane region was replaced by that from RyR1 was gated by InsP(3) and blocked by ryanodine. Activation mechanisms are conserved between InsP(3)R and RyR. Allosteric modulation of two similar domain interfaces within an N-terminal subunit reorients the first domain (SD or A domain), allowing it, through interactions of the second domain of an adjacent subunit (IBC-β or B domain), to gate the pore

    FIRBACK IV: Towards the nature of the 170microns source population

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    We present a detailed study of the brighter (>4σ> 4\sigma detections) sources in the 170μ\mum FIRBACK northern N1 ISO survey, with the help of complementary data in the optical, radio, and mid-IR domain. For 82% of them, an optical galaxy counterpart is identified, either as the unique source of the IR emission, or as part of a multiple identification. With less than 15% of AGNs, these sources are essentially local, moderate starbursters with a dominating cold dust component. and represent a population of cold galaxies rather neglected up to now. Their colours do not match those of the far-IR Cosmic IR Background (CIB), to which they contribute less than 5%. The bulk of the sources contributing to the CIB is thus to be searched for in more distant galaxies, possibly counterparts of the fainter FIRBACK sources still under study. These bright, local, galaxies however play an important role in the evolution of IR galaxies: they dominate the number counts at high 170 μ\mum fluxes, and represent half of the contribution at 250 mJy. Although not particularly massive (typically M*), they form more stars than a typical spiral galaxy and many are bulge dominated, that could represent the remnant of a former merger. The fainter part of this population may represent the missing link with the higher-z sources found in sub-mm observations.Comment: 40 pages, 10 figures, accepted for publication in Astronomy & Astrophysic

    Mapping the cold dust temperatures and masses of nearby Kingfish galaxies with Herschel

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    Taking advantage of the sensitivity and angular resolution of the Herschel Space Observatory at far-infrared and submm wavelengths, we aim to characterize the physical properties of cold dust within nearby galaxies and study the robustness of the parameters we derive using different modified blackbody models. For a pilot subsample of the KINGFISH program, we perform 2 temperature fits of the Spitzer and Herschel photometric data (24 to 500um), with a warm and a cold component, globally and in each resolution element.At global scales, we observe ranges of values for beta_c(0.8 to 2.5) and Tc(19.1 to 25.1K).We compute maps of our parameters with beta fixed or free to test the robustness of the temperature and dust surface density maps we deduce. When the emissivity is fixed, we observe temperature gradients as a function of radius.When the emissivity is fitted as a free parameter, barred galaxies tend to have uniform fitted emissivities.Gathering resolved elements in a Tc-beta_c diagram underlines an anti-correlation between the two parameters.It remains difficult to assess whether the dominant effect is the physics of dust grains, noise, or mixing along the line of sight and in the beam. We finally observe in both cases that the dust column density peaks in central regions of galaxies and bar ends (coinciding with molecular gas density enhancements usually found in these locations).We also quantify how the total dust mass varies with our assumptions about the emissivity index as well as the influence of the wavelength coverage used in the fits. We show that modified blackbody fits using a shallow emissivity (beta_c < 2.0) lead to significantly lower dust masses compared to the beta_c < 2.0 case, with dust masses lower by up to 50% if beta_c=1.5 for instance.The working resolution affects our total dust mass estimates: masses increase from global fits to spatially-resolved fits.Comment: 26 pages, 12 figures, 4 tables, accepted for publication in MNRAS, 2012 June 2

    The 1-1000 micron SEDs of far-infrared galaxies

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    Galaxies selected at 170um by the ISO FIRBACK survey represent the brightest \~10% of the Cosmic Infrared Background. Examining their nature in detail is therefore crucial for constraining models of galaxy evolution. Here we combine Spitzer archival data with previous near-IR, far-IR, and sub-mm observations of a representative sample of 22 FIRBACK galaxies spanning three orders of magnitude in infrared luminosity. We fit a flexible, multi-component, empirical SED model of star-forming galaxies designed to model the entire ~1-1000um wavelength range. The fits are performed with a Markov Chain Monte Carlo (MCMC) approach, allowing for meaningful uncertainties to be derived. This approach also highlights degeneracies such as between Td and beta, which we discuss in detail. From these fits and standard relations we derive: L_IR, L_PAH, SFR, tau_V, M_star, M_dust, Td, and beta. We look at a variety of correlations between these and combinations thereof in order to examine the physical nature of these galaxies. Our conclusions are supplemented by morphological examination of the sources, and comparison with local samples. We find the bulk of our sample to be consistent with fairly standard size and mass disk galaxies with somewhat enhanced star-formation relative to local spirals, but likely not bona fide starbursts. A few higher-z LIGs and ULIGs are also present, but contrary to expectation, they are weak mid-IR emitters and overall are consistent with star-formation over an extended cold region rather than concentrated in the nuclear regions. We discuss the implications of this study for understanding populations detected at other wavelengths, such as the bright 850um SCUBA sources or the faint Spitzer 24um sources.Comment: 19 pages, 20 figures, accepted for publication in MNRA

    Interlaboratory Evaluation of Rodent Pulmonary Responses to Engineered Nanomaterials: The NIEHS Nano GO Consortium

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    Background: Engineered nanomaterials (ENMs) have potential benefits, but they also present safety concerns for human health. Interlaboratory studies in rodents using standardized protocols are needed to assess ENM toxicity. Methods: Four laboratories evaluated lung responses in C57BL/6 mice to ENMs delivered by oropharyngeal aspiration (OPA), and three labs evaluated Sprague-Dawley (SD) or Fisher 344 (F344) rats following intratracheal instillation (IT). ENMs tested included three forms of titanium dioxide (TiO2) [anatase/rutile spheres (TiO2-P25), anatase spheres (TiO2-A), and anatase nanobelts (TiO2-NBs)] and three forms of multiwalled carbon nanotubes (MWCNTs) [original (O), purified (P), and carboxylic acid “functionalized� (F)]. One day after treatment, bronchoalveolar lavage fluid was collected to determine differential cell counts, lactate dehydrogenase (LDH), and protein. Lungs were fixed for histopathology. Responses were also examined at 7 days (TiO2 forms) and 21 days (MWCNTs) after treatment. Results: TiO2-A, TiO2-P25, and TiO2-NB caused significant neutrophilia in mice at 1 day in three of four labs. TiO2-NB caused neutrophilia in rats at 1 day in two of three labs, and TiO2-P25 and TiO2-A had no significant effect in any of the labs. Inflammation induced by TiO2 in mice and rats resolved by day 7. All MWCNT types caused neutrophilia at 1 day in three of four mouse labs and in all rat labs. Three of four labs observed similar histopathology to O-MWCNTs and TiO2-NBs in mice. Conclusions: ENMs produced similar patterns of neutrophilia and pathology in rats and mice. Although interlaboratory variability was found in the degree of neutrophilia caused by the three types of TiO2 nanoparticles, similar findings of relative potency for the three types of MWCNTs were found across all laboratories, thus providing greater confidence in these interlaboratory comparisons

    Learning for a Better Future

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    Various international scholars and associates of the PASCAL (Place, Social Capital and Learning Regions) International Observatory (Africa hub), under the auspices of the Centre for Local Economic Development (CENLED) based at the University of Johannesburg (UJ), have contributed chapters in this scholarly book. The book aims to demonstrate how a combination of globalisation, pandemics and the impact of innovation and technologies are driving towards a world in which traditional ideas are being challenged. The book carries forward a dual context and relevance: to South African social, educational, economic and cultural development, and the broader international context and action directed at how lifelong learning for all can be fostered in communities as a foundation for a just, human-centred, sustainable world. The distinctive contribution of this book to the production of a local body of knowledge lies in the symbiotic relationships between these objectives, so that South Africa could serve as a test case in working towards approaches that have a wider international significance

    Illustrations and guidelines for selecting statistical methods for quantifying spatial pattern in ecological data

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    This paper aims to provide guidance to ecologists with limited experience in spatial analysis to help in their choice of techniques, It uses examples to compare methods of spatial analysis for ecological field data. A taxonomy of different data types is presented, including point- and area-referenced data, with and without attributes. Spatially and non-spatially explicit data are distinguished. The effects of sampling and other transformations that convert one data type to another are discussed; the possible loss of spatial information is considered. Techniques for analyzing spatial pattern, developed in plant ecology, animal ecology, landscape ecology, geostatistics and applied statistics are reviewed briefly and their overlap in methodology and philosophy noted. The techniques are categorized according to their output and the inferences that may be drawn from them, in a discursive style without formulae. Methods are compared for four case studies with field data covering a range of types. These are: 1) percentage cover of three shrubs along a line transect 2) locations and volume of a desert plant in a I ha area: 3) a remotely-sensed spectral index and elevation from 10(5) km(2) of a mountainous region; and 4) land cover from three rangeland types within 800 km2 of a coastal region. Initial approaches utilize mapping, frequency distributions and variance-mean indices. Analysis techniques we compare include: local quadrat variance, block, quadrat variance, correlograms, variograms, angular correlation, directional variograms, wavelets, SADIE, nearest neighbour methods, Ripley's L(t), and various landscape ecology metrics. Our advice to ecologists is to use simple visualization techniques for initial analysis, and subsequently to select methods that are appropriate for the data type and that answer their specific questions of interest, It is usually prudent to employ several different techniques
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