5,389 research outputs found

    \u3ci\u3eLa Caja de Pandora\u3c/i\u3e: Improving Access to Hospice Care among Hispanic and African-American Patients

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    Many patients clinging to hope in the form of potentially curative treatment could benefit from hospice services, but, for the most part, it is not until the patient accepts the finality of his or her condition that the physical, psychological and social benefits of hospice care become accessible to the patient and his or her family. Under current Medicare regulations and other health care payers’ policies, patients must abandon the hope of curative treatment before opting for hospice services. As a result, many terminally ill patients access the services late, sometimes a few hours before death. Scholars have proposed that such a barrier to access, present in Medicare, Medicaid and other health insurers’ coverage rules, may be responsible for lower utilization of hospice services and later access to hospice services than has been proven to be beneficial to patients and their families. This problem becomes even more significant, and other barriers beside coverage rules become apparent, when considering the health care needs of racial and ethnic minorities in the United States. Not only do patients in racial and ethnic minority groups access hospice late, like the general population, but they also access it in far fewer numbers. The statistics are especially stark among African-American and Hispanic patients. This Article explores these powerful statistics, seeking to shed light on the end-of-life decision-making process for Hispanics and African-Americans, with an eye toward identifying barriers to access and utilization of hospice services among those populations

    Disperse two-phase flows, with applications to geophysical problems

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    In this paper we study the motion of a fluid with several dispersed particles whose concentration is very small (smaller than 10−3), with possible applications to problems coming from geophysics, meteorology, and oceanography. We consider a very dilute suspension of heavy particles in a quasi-incompressible fluid (low Mach number). In our case the Stokes number is small and --as pointed out in the theory of multiphase turbulence-- we can use an Eulerian model instead of a Lagrangian one. The assumption of low concentration allows us to disregard particle--particle interactions, but we take into account the effect of particles on the fluid (two-way coupling). In this way we can study the physical effect of particle inertia (and not only passive tracers), with a model similar to the Boussinesq equations. The resulting model is used in both direct numerical simulations and large eddy simulations of a dam-break (lock-exchange) problem, which is a well-known academic test case. Keywords: Dilute suspensions, Eulerian models, direct and large eddy simulations, slightly compressible flows, dam-break (lock-exchange) problem

    Deep learning for inferring cause of data anomalies

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    Daily operation of a large-scale experiment is a resource consuming task, particularly from perspectives of routine data quality monitoring. Typically, data comes from different sub-detectors and the global quality of data depends on the combinatorial performance of each of them. In this paper, the problem of identifying channels in which anomalies occurred is considered. We introduce a generic deep learning model and prove that, under reasonable assumptions, the model learns to identify 'channels' which are affected by an anomaly. Such model could be used for data quality manager cross-check and assistance and identifying good channels in anomalous data samples. The main novelty of the method is that the model does not require ground truth labels for each channel, only global flag is used. This effectively distinguishes the model from classical classification methods. Being applied to CMS data collected in the year 2010, this approach proves its ability to decompose anomaly by separate channels.Comment: Presented at ACAT 2017 conference, Seattle, US

    Stigma and Criminalization of Mental Health in an Inpatient Versus Jail Setting

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    Stigmatization is the perceived, negative stereotype assigned to a group of individuals. This stigmatization has contributed to the criminalization of mental health, meaning that individuals with mental health issues are more likely to be arrested for behaviors that are not criminal. This project examines mental health stigma toward an individual in a psychiatric setting and a correctional setting. We hypothesized that when reading a vignette about an individual experiencing a mental health crisis, participants will stigmatize them more if they are incarcerated than if they are in a psychiatric facility. Results showed that participants exhibited a higher level of discrimination stigma for the jail condition than for the psychiatric facility condition. This research has important implications for those individuals who are incarcerated, experience mental health issues, and are more susceptible to discriminatory beliefs

    Neural Correlates of Fear in the Periaqueductal Gray

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    International audienceThe dorsal and ventral periaqueductal gray (dPAG and vPAG, respectively) are embedded in distinct survival networks that coordinate, respectively, innate and conditioned fear-evoked freezing. However, the information encoded by the PAG during these survival behaviors is poorly understood. Recordings in the dPAG and vPAG in rats revealed differences in neuronal activity associated with the two behaviors. During innate fear, neuronal responses were significantly greater in the dPAG compared with the vPAG. After associative fear conditioning and during early extinction (EE), when freezing was maximal, a field potential was evoked in the PAG by the auditory fear conditioned stimulus (CS). With repeated presentations of the unreinforced CS, animals displayed progressively less freezing accompanied by a reduction in event-related field potential amplitude. During EE, the majority of dPAG and vPAG units increased their firing frequency, but spike-triggered averaging showed that only ventral activity during the presentation of the CS was significantly coupled to EMG-related freezing behavior. This PAG–EMG coupling was only present for the onset of freezing activity during the CS in EE. During late extinction, a subpopulation of units in the dPAG and vPAG continued to show CS-evoked responses; that is, they were extinction resistant. Overall, these findings support roles for the dPAG in innate and conditioned fear and for the vPAG in initiating but not maintaining the drive to muscles to generate conditioned freezing. The existence of extinction-susceptible and extinction-resistant cells also suggests that the PAG plays a role in encoding fear memories

    When fast is better: Protein folding fundamentals and mechanisms from ultrafast approaches

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    Protein folding research stalled for decades because conventional experiments indicated that proteins fold slowly and in single strokes, whereas theory predicted a complex interplay between dynamics and energetics resulting in myriad microscopic pathways. Ultrafast kinetic methods turned the field upside down by providing the means to probe fundamental aspects of folding, test theoretical predictions and benchmark simulations. Accordingly, experimentalists could measure the timescales for all relevant folding motions, determine the folding speed limit and confirm that folding barriers are entropic bottlenecks. Moreover, a catalogue of proteins that fold extremely fast (microseconds) could be identified. Such fast-folding proteins cross shallow free energy barriers or fold downhill, and thus unfold with minimal co-operativity (gradually). A new generation of thermodynamic methods has exploited this property to map folding landscapes, interaction networks and mechanisms at nearly atomic resolution. In parallel, modern molecular dynamics simulations have finally reached the timescales required to watch fast-folding proteins fold and unfold in silico. All of these findings have buttressed the fundamentals of protein folding predicted by theory, and are now offering the first glimpses at the underlying mechanisms. Fast folding appears to also have functional implications as recent results connect downhill folding with intrinsically disordered proteins, their complex binding modes and ability to moonlight. These connections suggest that the coupling between downhill (un)folding and binding enables such protein domains to operate analogically as conformational rheostats

    Ash plume properties retrieved from infrared images: a forward and inverse modeling approach

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    We present a coupled fluid-dynamic and electromagnetic model for volcanic ash plumes. In a forward approach, the model is able to simulate the plume dynamics from prescribed input flow conditions and generate the corresponding synthetic thermal infrared (TIR) image, allowing a comparison with field-based observations. An inversion procedure is then developed to retrieve ash plume properties from TIR images. The adopted fluid-dynamic model is based on a one-dimensional, stationary description of a self-similar (top-hat) turbulent plume, for which an asymptotic analytical solution is obtained. The electromagnetic emission/absorption model is based on the Schwarzschild's equation and on Mie's theory for disperse particles, assuming that particles are coarser than the radiation wavelength and neglecting scattering. In the inversion procedure, model parameters space is sampled to find the optimal set of input conditions which minimizes the difference between the experimental and the synthetic image. Two complementary methods are discussed: the first is based on a fully two-dimensional fit of the TIR image, while the second only inverts axial data. Due to the top-hat assumption (which overestimates density and temperature at the plume margins), the one-dimensional fit results to be more accurate. However, it cannot be used to estimate the average plume opening angle. Therefore, the entrainment coefficient can only be derived from the two-dimensional fit. Application of the inversion procedure to an ash plume at Santiaguito volcano (Guatemala) has allowed us to retrieve the main plume input parameters, namely the initial radius b0b_0, velocity U0U_0, temperature T0T_0, gas mass ratio n0n_0, entrainment coefficient kk and their related uncertainty. Moreover, coupling with the electromagnetic model, we have been able to obtain a reliable estimate of the equivalent Sauter diameter dsd_s of the total particle size distribution. The presented method is general and, in principle, can be applied to the spatial distribution of particle concentration and temperature obtained by any fluid-dynamic model, either integral or multidimensional, stationary or time-dependent, single or multiphase. The method discussed here is fast and robust, thus indicating potential for applications to real-time estimation of ash mass flux and particle size distribution, which is crucial for model-based forecasts of the volcanic ash dispersal process

    Simultaneous Continuation of Infinitely Many Sinks Near a Quadratic Homoclinic Tangency

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    We prove that the C3C^3 diffeomorphisms on surfaces, exhibiting infinitely many sinksnear the generic unfolding of a quadratic homoclinic tangency of a dissipative saddle, can be perturbed along an infinite dimensional manifold of C3C^3 diffeomorphisms such that infinitely many sinks persist simultaneously. On the other hand, if they are perturbed along one-parameter families that unfold generically the quadratic tangencies, then at most a finite number of those sinks have continuation
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