1,666 research outputs found

    Temperature and salinity tolerances of young Gulf of California grunion, Leuresthes sardina (Atheriniformes: Atherinidae)

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    Temperature and salinity tolerances were determined for laboratory-reared larval and juvenile Gulf of California grunion, Leuresthes sardina. The fish were hatched in the laboratory from artificially fertilized eggs obtained from spawning adults captured with a beach seine...

    Martin Luther and the peasants' revolt

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    [INTRODUCTION] The student of the Middle Ages, particularly the time of the Peasants' Revolt (1525), is likely to come from his study with a considerable number of questiohs in his mind. That was a time of intense rivalry, open bitterness, and rank partisanship. Seemingly much of the same spirit and practice has descended upon the. shoulders of those who have since acted as historians of that period, and much, if not all what has been written bears the mark of bias and is open to the charge of partizanship. The facts,with a right estimate as to their value, and the correct inference to be drawn,- these are difficult to determine. One needs to remember also, that the very character of the period with its state of wide, spread unrest, its religious, social and political uncertainties, was reflected in the lives and actions of the individual men of the time. They thought, spoke and acted, usually with much vigor, and (as men usually do) from mixed motives. If we sieze upon certain of their conceptions and deeds it would be to condemn them unmercifully in the judgment of today, but upon closer and fuller study there come to light the complex reasons and explanations which raise the question: Should they, products of their age and living by its standards, be subjected too searchingly to the more rigid tests of the modern conscience?

    Ant mosaics in Bornean primary rain forest high canopy depend on spatial scale, time of day, and sampling method.

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    Background: Competitive interactions in biological communities can be thought of as giving rise to "assembly rules" that dictate the species that are able to co-exist. Ant communities in tropical canopies often display a particular pattern, an "ant mosaic", in which competition between dominant ant species results in a patchwork of mutually exclusive territories. Although ant mosaics have been well-documented in plantation landscapes, their presence in pristine tropical forests remained contentious until recently. Here we assess presence of ant mosaics in a hitherto under-investigated forest stratum, the emergent trees of the high canopy in primary tropical rain forest, and explore how the strength of any ant mosaics is affected by spatial scale, time of day, and sampling method. Methods: To test whether these factors might impact the detection of ant mosaics in pristine habitats, we sampled ant communities from emergent trees, which rise above the highest canopy layers in lowland dipterocarp rain forests in North Borneo (38.8-60.2 m), using both baiting and insecticide fogging. Critically, we restricted sampling to only the canopy of each focal tree. For baiting, we carried out sampling during both the day and the night. We used null models of species co-occurrence to assess patterns of segregation at within-tree and between-tree scales. Results: The numerically dominant ant species on the emergent trees sampled formed a diverse community, with differences in the identity of dominant species between times of day and sampling methods. Between trees, we found patterns of ant species segregation consistent with the existence of ant mosaics using both methods. Within trees, fogged ants were segregated, while baited ants were segregated only at night. Discussion: We conclude that ant mosaics are present within the emergent trees of the high canopy of tropical rain forest in Malaysian Borneo, and that sampling technique, spatial scale, and time of day interact to determine observed patterns of segregation. Restricting sampling to only emergent trees reveals segregatory patterns not observed in ground-based studies, confirming previous observations of stronger segregation with increasing height in the canopy.Kalsum M. Yusah was funded by the South East Asia Rainforest Research Partnership (SEARRP), a Malaysian Ministry of Higher Education Fundamental Research Grant (FRG0373- STWN- 1/ 2014), and a Universiti Malaysia Sabah New Lecturer Grant Scheme grant (SLB0071- STWN- 2013). Tom M. Fayle was funded by a Czech Science Foundation standard grant (16-09427S)

    Tributes to Dean James Forsyth

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    A Spatially Resolved Study of the Synchrotron Emission and Titanium in Tycho's Supernova Remnant with NuSTAR

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    We report results from deep observations (~750 ks) of Tycho's supernova remnant (SNR) with NuSTAR. Using these data, we produce narrow-band images over several energy bands to identify the regions producing the hardest X-rays and to search for radioactive decay line emission from 44Ti. We find that the hardest (>10 keV) X-rays are concentrated in the southwest of Tycho, where recent Chandra observations have revealed high emissivity "stripes" associated with particles accelerated to the knee of the cosmic-ray spectrum. We do not find evidence of 44Ti, and we set limits on its presence and distribution within the SNR. These limits correspond to a upper-limit 44Ti mass of M44 < 2.4x10^-4 M_sun for a distance of 2.3 kpc. We perform spatially resolved spectroscopic analysis of sixty-six regions across Tycho. We map the best-fit rolloff frequency of the hard X-ray spectra, and we compare these results to measurements of the shock expansion and ambient density. We find that the highest energy electrons are accelerated at the lowest densities and in the fastest shocks, with a steep dependence of the roll-off frequency with shock velocity. Such a dependence is predicted by models where the maximum energy of accelerated electrons is limited by the age of the SNR rather than by synchrotron losses, but this scenario requires far lower magnetic field strengths than those derived from observations in Tycho. One way to reconcile these discrepant findings is through shock obliquity effects, and future observational work is necessary to explore the role of obliquity in the particle acceleration process.Comment: 12 pages, 12 figures, ApJ in pres

    Prescription analgesia and adjuvant use by pain severity at admission among nursing home residents with non-malignant pain

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    OBJECTIVE: We estimated the use of prescribed analgesics and adjuvants among nursing home residents without cancer who reported pain at their admission assessment, in relation to resident-reported pain severity. METHODS: Medicare Part D claims were used to define 3 classes of analgesics and 7 classes of potential adjuvants on the 21st day after nursing home admission (or the day of discharge for residents discharged before that date) among 180,780 residents with complete information admitted between January 1, 2011 and December 9, 2016, with no cancer diagnosis. RESULTS: Of these residents, 27.9% reported mild pain, 46.6% moderate pain, and 25.6% reported severe pain. The prevalence of residents in pain without Part D claims for prescribed analgesic and/or adjuvant medications was 47.3% among those reporting mild pain, 35.7% among those with moderate pain, and 24.8% among those in severe pain. Among residents reporting severe pain, 33% of those \u3e /= 85 years of age and 35% of those moderately cognitively impaired received no prescription analgesics/adjuvants. Use of all classes of prescribed analgesics and adjuvants increased with resident-reported pain severity, and the concomitant use of medications from multiple classes was common. CONCLUSION: Among nursing home residents with recognized pain, opportunities to improve the pharmacologic management of pain, especially among older residents, and those living with cognitive impairments exist

    Role of science in ecosystem management

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    Roberts argues that in order to implement ecosystem management, resource management must switch its ecological perspective from an individual-and population-based focus to ecosystem-and landscape-based ecology; from an object (form) to context (function) approach; and adopt a multi-scalar modeling approach. A major role for science in EM is to predict ecosystem behavior under alternative management strategies. Wilcox, Risbrudt, Thomas, and Kessler all emphasized the critical role of a higher level of science, although Daniels pointed out that there is a risk of creating a politics of expertise. Thus participating scientists have a strong responsibility to communicate their knowledge to the public in understandable ways

    The Hard X-Ray View of the Young Supernova Remnant G1.9+0.3

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    NuSTAR observed G1.9+0.3, the youngest known supernova remnant in the Milky Way, for 350 ks and detected emission up to ∼\sim30 keV. The remnant's X-ray morphology does not change significantly across the energy range from 3 to 20 keV. A combined fit between NuSTAR and CHANDRA shows that the spectrum steepens with energy. The spectral shape can be well fitted with synchrotron emission from a power-law electron energy distribution with an exponential cutoff with no additional features. It can also be described by a purely phenomenological model such as a broken power-law or a power-law with an exponential cutoff, though these descriptions lack physical motivation. Using a fixed radio flux at 1 GHz of 1.17 Jy for the synchrotron model, we get a column density of NH_{\rm H} = (7.23±0.07)×1022(7.23\pm0.07) \times 10^{22} cm−2^{-2}, a spectral index of α=0.633±0.003\alpha=0.633\pm0.003, and a roll-off frequency of νrolloff=(3.07±0.18)×1017\nu_{\rm rolloff}=(3.07\pm0.18) \times 10^{17} Hz. This can be explained by particle acceleration, to a maximum energy set by the finite remnant age, in a magnetic field of about 10 μ\muG, for which our roll-off implies a maximum energy of about 100 TeV for both electrons and ions. Much higher magnetic-field strengths would produce an electron spectrum that was cut off by radiative losses, giving a much higher roll-off frequency that is independent of magnetic-field strength. In this case, ions could be accelerated to much higher energies. A search for 44^{44}Ti emission in the 67.9 keV line results in an upper limit of 1.5×10−51.5 \times 10^{-5}  ph cm−2 s−1\,\mathrm{ph}\,\mathrm{cm}^{-2}\,\mathrm{s}^{-1} assuming a line width of 4.0 keV (1 sigma).Comment: 9 pages, 6 figures, accepted Ap
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