4,122 research outputs found

    Sticky physics of joy: On the dissolution of spherical candies

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    Assuming a constant mass-decrease per unit-surface and -time we provide a very simplistic model for the dissolution process of spherical candies. The aim is to investigate the quantitative behavior of the dissolution process throughout the act of eating the candy. In our model we do not take any microscopic mechanism of the dissolution process into account, but rather provide an estimate which is based on easy-to-follow calculations. Having obtained a description based on this calculation, we confirm the assumed behavior by providing experimental data of the dissolution process. Besides a deviation from our prediction caused by the production process of the candies below a diameter of 2 mm, we find good agreement with our model-based expectations. Serious questions on the optimal strategy of enjoying a candy will be addressed, like whether it is wise to split the candy by breaking it with the teeth or not

    Running the Health Care Marathon: An Ethnography of a Charitable Clinic in a Rural Appalachian Community

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    Appalachia is characterized as being a place of health inequalities, including substandard health care access. Health disparities in access to health care persist in the region, and many Tennessee residents are unable to afford premiums, if they can afford insurance at all. Uninsured individuals rely on community based free clinics, which serve as health care safety nets and allowing people to obtain limited health care. This ethnographic investigation, involving semi-structured interviews and participant-observation of the Blackberry Spruce Free Clinic, provides insight into the continued need of health care safety net resources. This research provides a patient’s perspective on the barriers to care for the uninsured, the difficulties in managing chronic illnesses and other medical needs when relying on charity care, and the problems of clinic management in its role as a temporary solution for the uninsured population

    Asymptotic Normalization Coefficients for 13C+p->14N

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    The 13C(14N,13C)14N^{13}C(^{14}N,^{13}C)^{14}N proton exchange reaction has been measured at an incident energy of 162 MeV. Angular distributions were obtained for proton transfer to the ground and low lying excited states in 14N^{14}N. Elastic scattering of 14N^{14}N on 13C^{13}C also was measured out to the rainbow angle region in order to find reliable optical model potentials. Asymptotic normalization coefficients for the system 13C+p→14N^{13}C+p\to {}^{14}N have been found for the ground state and the excited states at 2.313, 3.948, 5.106 and 5.834 MeV in 14N^{14}N. These asymptotic normalization coefficients will be used in a determination of the S-factor for 7Be(p,γ)8B^{7}Be(p,\gamma)^{8}B at solar energies from a measurement of the proton transfer reaction 14N(7Be,8B)13C^{14}N(^{7}Be,^{8}B)^{13}C.Comment: 5 pages, 6 figure

    Using Unmanned Aerial Vehicles for Bird Harassment on Fish Ponds

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    The effects of aquaculture decline on piscivorous birds in the Mississippi Delta concern catfish farmers, with possible increases in fish loss and disease transmission. Piscivorous birds quickly habituate to most current methods of harassment (loud noises and visual disturbances) leading to increased depredation and disease. Our study was designed to test the efficacy of using unmanned aerial vehicles (UAVs) to effectively control piscivorous birds at fish farms. We hypothesized that a UAV would be more efficient at reducing the number of fish-eating birds on fish ponds than current forms of harassment. We conducted pre-treatment bird surveys, harassment observations, and post-treatment surveys at each experimental unit before and after each treatment on the same treatment days on 6 study sites in the Mississippi Alluvial Valley. The results of this study indicate that UAV harassment did not reduce piscivorous bird abundance more than human harassment in a 2-year field experiment

    Prospective evaluation of multiplicative hybrid earthquake forecasting models in California

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    The Regional Earthquake Likelihood Models (RELM) experiment, conducted within the Collaboratory for the Study of Earthquake Predictability (CSEP), showed that the smoothed seismicity (HKJ) model by Helmstetter et al. was the most informative time-independent earthquake model in California during the 2006–2010 evaluation period. The diversity of competing forecast hypotheses and geophysical data sets used in RELM was suitable for combining multiple models that could provide more informative earthquake forecasts than HKJ. Thus, Rhoades et al. created multiplicative hybrid models that involve the HKJ model as a baseline and one or more conjugate models. In retrospective evaluations, some hybrid models showed significant information gains over the HKJ forecast. Here, we prospectively assess the predictive skills of 16 hybrids and 6 original RELM forecasts at a 0.05 significance level, using a suite of traditional and new CSEP tests that rely on a Poisson and a binary likelihood function. In addition, we include consistency test results at a Bonferroni-adjusted significance level of 0.025 to address the problem of multiple tests. Furthermore, we compare the performance of each forecast to that of HKJ. The evaluation data set contains 40 target events recorded within the CSEP California testing region from 2011 January 1 to 2020 December 31, including the 2016 Hawthorne earthquake swarm in southwestern Nevada and the 2019 Ridgecrest sequence. Consistency test results show that most forecasting models overestimate the number of earthquakes and struggle to explain the spatial distribution of epicenters, especially in the case of seismicity clusters. The binary likelihood function significantly reduces the sensitivity of spatial log-likelihood scores to clustering, however; most models still fail to adequately describe spatial earthquake patterns. Contrary to retrospective analyses, our prospective test results show that none of the models are significantly more informative than the HKJ benchmark forecast, which we interpret to be due to temporal instabilities in the fit that forms hybrids. These results suggest that smoothing high-resolution, small earthquake data remains a robust method for forecasting moderate-to-large earthquakes over a period of 5–15 yr in California.This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 821115, Real-time earthquake rIsk reduction for a reSilient Europe (RISE), http://www.rise-eu.org). Additionally, this research was supported by the Southern California Earthquake Center (contribution no. 11011). SCEC is funded by NSF Cooperative agreement EAR-1600087 and USGS Cooperative agreement G17AC00047

    A Nonhomologous End-Joining Mutant for Neurospora sitophila Research

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    Disruption of the nonhomologous end-joining (NHEJ) pathway has been shown to increase the efficiency of transgene integration into targeted genomic locations of Neurospora crassa and other fungi. Here, we report that a similar phenomenon occurs in a second Neurospora species: N. sitophila. Specifically, we show that deletion of N. sitophila mus-51 increases the efficiency of targeted-transgene integration, presumably by disrupting NHEJ. Researchers interested in obtaining the N. sitophila mus-51∆ strains described in this study can obtain them from the Fungal Genetics Stock Center (FGSC, Kansas State University, Manhattan, KS)
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