5,529 research outputs found

    Fowl communicate the size, speed and proximity of avian stimuli through graded structure in referential alarm calls

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    Many animals produce alarm calls that warn conspecifics about predators. In some species, alarm calls communicate continuous traits associated with a predator encounter, such as its level of threat. In other species, alarm calls communicate categorical traits, such as predator class (e.g. avian versus terrestrial), and are consequently considered functionally referential. In theory, functionally referential alarm calls can simultaneously communicate continuously distributed traits, though examples of such calls are rare. Such dual-function calls could be adaptive because they would enable receivers to tailor their responses to a specific predator class, as well as to more subtle characteristics of individual attacks. Here, we tested whether male fowl (Gallus gallus) communicate continuous variation in avian stimuli through graded structure in their functionally referential aerial alarm calls. In the first experiment, we held male fowl in an indoor test cage and allowed them to view wild birds flying past a window. We recorded their alarm calls and compared the structure to the size, speed, and proximity of the eliciting stimuli. Stimuli that appeared closer, larger, and faster elicited alarm calls that were shorter, louder, clearer, and lower in frequency. In the second experiment, we broadcast alarm calls to foraging females and compared their responses to the graded structural changes documented earlier. Females exhibited greater initial responses and finished feeding later in response to louder alarm calls. Together, these results show that fowl communicate the size, speed and proximity of avian stimuli through graded variation in their functionally referential aerial alarm calls

    A comparison of handwritten and computer-assisted prescriptions in an intensive care unit

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    BACKGROUND: We conducted a prospective comparative study to evaluate the potential benefit of computer-assisted prescribing (CAP). We compared the accuracy, completeness and time use of CAP with that of conventional handwritten prescribing at the intensive care unit (ICU) of the John Radcliffe Hospital, Oxford, UK. RESULTS: Twenty-five clinicians and 2409 drug entries were evaluated for accuracy, completeness, legibility and time spent prescribing. One hundred and twenty-eight handwritten and 110 CAP charts were monitored. One hundred percent of CAP charts were complete compared to 47% of handwritten charts.Drug prescriptions were divided into three categories: intravenous fluids, intravenous infusions and intermittent drugs. Percentage of correct entries in each category were 64%, 47.5% and 90% for handwritten, compared to 48%, 32% and 90% for CAP charts, respectively.The mean time taken to prescribe was 20 s for hand written prescribing and 55 s for CAP. CONCLUSIONS: Computer-assisted prescriptions were more complete, signed and dated than handwritten prescriptions. Errors in prescribing, including failure to discontinue a drug were not reduced by CAP. Handwritten prescribing was quicker than CAP. Simple enhancements of the computer software could be introduced which might overcome these deficiencies. CAP was successfully integrated into clinical practice in the ICU

    Relativistic Corrections in White Dwarf Asteroseismology

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    With the precision now afforded by modern space-based photometric observations from the retired K2 and current TESS missions, the effects of general relativity (GR) may be detectable in the light curves of pulsating white dwarfs (WDs). Almost all WD models are calculated using a Newtonian description of gravity and hydrodynamics. To determine if inclusion of GR leads to observable effects, we used idealized models of compact stars and made side-by-side comparison of mode periods computed using a (i) Newtonian and (ii) GR description of the equilibrium structure and nonradial pulsations. For application to white dwarfs, it is only necessary to include the first post-Newtonian (1PN) approximation to GR. The mathematical nature of the linear nonradial pulsation problem is then qualitatively unchanged and the GR corrections can be written as extensions of the classic Dziembowski equations. As such, GR effects might easily be included in existing asteroseismology codes. The idealized stellar models are (i) \pn1 relativistic polytropes and (ii) stars with cold degenerate-electron equation of state featuring a near-surface chemical transition from μe=2\mu_e = 2 to μe=1\mu_e = 1, simulating a surface hydrogen layer. Comparison of Newtonian and 1PN normal mode periods reveals fractional differences on the order of the surface gravitational redshift zz. For a typical WD, this fractional difference is ∼10−4\sim 10^{-4} and is greater than the period uncertainty σΠ/Π\sigma_{\Pi}/\Pi of many white dwarf pulsation modes observed by TESS. A consistent theoretical modeling of periods observed in these stars should in principle include GR effects to 1PN order

    Chronic opioid pretreatment potentiates the sensitization of fear learning by trauma.

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    Despite the large comorbidity between PTSD and opioid use disorders, as well as the common treatment of physical injuries resulting from trauma with opioids, the ability of opioid treatments to subsequently modify PTSD-related behavior has not been well studied. Using the stress-enhanced fear learning (SEFL) model for PTSD, we characterized the impact of chronic opioid regimens on the sensitization of fear learning seen following traumatic stress in mice. We demonstrate for the first time that chronic opioid pretreatment is able to robustly augment associative fear learning. Highlighting aversive learning as the cognitive process mediating this behavioral outcome, these changes were observed after a considerable period of drug cessation, generalized to learning about multiple aversive stimuli, were not due to changes in stimulus sensitivity or basal anxiety, and correlated with a marker of synaptic plasticity within the basolateral amygdala. Additionally, these changes were not observed when opioids were given after the traumatic event. Moreover, we found that neither reducing the frequency of opioid administration nor bidirectional manipulation of acute withdrawal impacted the subsequent enhancement in fear learning seen. Given the fundamental role of associative fear learning in the generation and progression of PTSD, these findings are of direct translational relevance to the comorbidity between opioid dependence and PTSD, and they are also pertinent to the use of opioids for treating pain resulting from traumas involving physical injuries

    Feasibility of a self-completed history questionnaire in women requesting repeat combined hormonal contraception.

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    OBJECTIVE: To measure agreement between the client's and the clinician's responses to questions regarding client history as answered on a questionnaire based on the UK Medical Eligibility Criteria for Contraceptive Use (UKMEC) for combined hormonal contraception (CHC). METHODS: Clients aged 18 years and over, attending a central London community contraceptive clinic requesting a repeat supply of CHC, completed a history questionnaire and an evaluation form. Clinicians then completed their copy of the same questionnaire during the consultation. Percentage agreement and the Kappa statistic were used to assess the level of client-clinician agreement. RESULTS: Data from 328 client-clinician pairs were analysed. Agreement was above 93% for all identified risk factors. There was complete agreement for thrombosis, diabetes, stroke, cancer and liver problems. Least agreement was noted in the recording of migraine and abnormal bleeding. For all risk factors except smoking, the proportion of clients reporting a risk factor was more than the proportion of clinicians reporting a risk factor. No clinically important information relevant to a particular client's use of CHC was missed and none of them would have been wrongly prescribed the CHC based just on their self-completed questionnaires. Most women (97%) were happy with this method of history taking. CONCLUSIONS: A self-completed history questionnaire is acceptable to women and can potentially replace traditional routine medical history taking for continuing CHC. Women completed the questionnaire with a high degree of reliability. There was complete client-clinician agreement on UKMEC Category 4 criteria. Overall, clients reported more risk factors than clinicians, which increases the safety of the questionnaire

    Time for responsible peatland agriculture

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    Letter

    The Protostellar Mass Function

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    The protostellar mass function (PMF) is the Present-Day Mass Function of the protostars in a region of star formation. It is determined by the initial mass function weighted by the accretion time. The PMF thus depends on the accretion history of protostars and in principle provides a powerful tool for observationally distinguishing different protostellar accretion models. We consider three basic models here: the Isothermal Sphere model (Shu 1977), the Turbulent Core model (McKee & Tan 2003), and an approximate representation of the Competitive Accretion model (Bonnell et al. 1997, 2001a). We also consider modified versions of these accretion models, in which the accretion rate tapers off linearly in time. Finally, we allow for an overall acceleration in the rate of star formation. At present, it is not possible to directly determine the PMF since protostellar masses are not currently measurable. We carry out an approximate comparison of predicted PMFs with observation by using the theory to infer the conditions in the ambient medium in several star-forming regions. Tapered and accelerating models generally agree better with observed star-formation times than models without tapering or acceleration, but uncertainties in the accretion models and in the observations do not allow one to rule out any of the proposed models at present. The PMF is essential for the calculation of the Protostellar Luminosity Function, however, and this enables stronger conclusions to be drawn (Offner & McKee 2010).Comment: 16 pages, 8 figures, published in Ap

    Diagnosis of Elder Abuse in U.S. Emergency Departments

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    To estimate the proportion of visits to United States emergency departments (EDs) receiving a diagnosis of elder abuse using two nationally representative datasets
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