39 research outputs found
Stability of the fragments and thermalization at peak center-of-mass energy
We simulate the central reactions of nearly symmetric, and asymmetric
systems, for the energies at which the maximum production of IMFs occurs
(E).This study is carried out by using hard EOS along with
cugnon cross section and employing MSTB method for clusterization. We study the
various properties of fragments. The stability of fragments is checked through
persistence coefficient and gain term. The information about the thermalization
and stopping in heavy-ion collisions is obtained via relative momentum,
anisotropy ratio, and rapidity distribution. We find that for a complete
stopping of incoming nuclei very heavy systems are required. The mass
dependence of various quantities (such as average and maximum central density,
collision dynamics as well as the time zone for hot and dense nuclear matter)
is also presented. In all cases (i.e., average and maximum central density,
collision dynamics as well as the time zone for hot and dense nuclear matter) a
power law dependence is obtained.Comment: 21 Pages, 8 Figure
Multi-Dimensional, Compressible Viscous Flow on a Moving Voronoi Mesh
Numerous formulations of finite volume schemes for the Euler and
Navier-Stokes equations exist, but in the majority of cases they have been
developed for structured and stationary meshes. In many applications, more
flexible mesh geometries that can dynamically adjust to the problem at hand and
move with the flow in a (quasi) Lagrangian fashion would, however, be highly
desirable, as this can allow a significant reduction of advection errors and an
accurate realization of curved and moving boundary conditions. Here we describe
a novel formulation of viscous continuum hydrodynamics that solves the
equations of motion on a Voronoi mesh created by a set of mesh-generating
points. The points can move in an arbitrary manner, but the most natural motion
is that given by the fluid velocity itself, such that the mesh dynamically
adjusts to the flow. Owing to the mathematical properties of the Voronoi
tessellation, pathological mesh-twisting effects are avoided. Our
implementation considers the full Navier-Stokes equations and has been realized
in the AREPO code both in 2D and 3D. We propose a new approach to compute
accurate viscous fluxes for a dynamic Voronoi mesh, and use this to formulate a
finite volume solver of the Navier-Stokes equations. Through a number of test
problems, including circular Couette flow and flow past a cylindrical obstacle,
we show that our new scheme combines good accuracy with geometric flexibility,
and hence promises to be competitive with other highly refined Eulerian
methods. This will in particular allow astrophysical applications of the AREPO
code where physical viscosity is important, such as in the hot plasma in galaxy
clusters, or for viscous accretion disk models.Comment: 26 pages, 21 figures. Submitted to MNRA
Generalized Isoscaling of Isotopic Distributions
Generalized isoscaling relationships are proposed that may permit one to
relate the isotopic distributions of systems that may not be at the same
temperature. The proposed relationships are applied to multifragmentation
excitation functions for central Kr+Nb and Ar+Sc collisions.Comment: 20 pages, 5 figure
Using enhanced number and brightness to measure protein oligomerization dynamics in live cells
Protein dimerization and oligomerization are essential to most cellular functions, yet measurement of the size of these oligomers in live cells, especially when their size changes over time and space, remains a challenge. A commonly used approach for studying protein aggregates in cells is number and brightness (N&B), a fluorescence microscopy method that is capable of measuring the apparent average number of molecules and their oligomerization (brightness) in each pixel from a series of fluorescence microscopy images. We have recently expanded this approach in order to allow resampling of the raw data to resolve the statistical weighting of coexisting species within each pixel. This feature makes enhanced N&B (eN&B) optimal for capturing the temporal aspects of protein oligomerization when a distribution of oligomers shifts toward a larger central size over time. In this protocol, we demonstrate the application of eN&B by quantifying receptor clustering dynamics using electron-multiplying charge-coupled device (EMCCD)-based total internal reflection microscopy (TIRF) imaging. TIRF provides a superior signal-to-noise ratio, but we also provide guidelines for implementing eN&B in confocal microscopes. For each time point, eN&B requires the acquisition of 200 frames, and it takes a few seconds up to 2 min to complete a single time point. We provide an eN&B (and standard N&B) MATLAB software package amenable to any standard confocal or TIRF microscope. The software requires a high-RAM computer (64 Gb) to run and includes a photobleaching detrending algorithm, which allows extension of the live imaging for more than an hour
Healthcare Service Use, Help-seeking Behaviors, and Health and Wellbeing in Attenuated Psychosis
Persons with serious mental illness (SMI) receive poorer-than-standard healthcare, contributing to a 20-year reduction in the average life expectancy of persons with SMI. While extant literature describes the health disparities experienced by persons with SMI, little research examines the relationship between attenuated psychotic symptoms, healthcare service use, and help-seeking behaviors that may contribute to the disparities in this vulnerable population. This study explores the relationships between attenuated psychotic symptoms, physical health symptoms and related distress, healthcare service use, and help-seeking intentions to better understand health disparities in vulnerable and marginalized populations, such as individuals with SMI. Only a portion of individuals exhibiting symptoms meet criteria for a psychiatric illness based on the psychosis continuum. Subjects with Attenuated Psychotic Symptoms (APS; symptoms that are qualitatively similar to those of frank psychosis but attenuated in severity) were studied to examine hypotheses related to the health disparities and healthcare service inequities present in the SMI population because they often have analogous health disparities, comparable psychological and social characteristics as persons with SMI, and represent roughly 2% of college samples, which approximates the epidemiological risk of psychosis. Data was collected from one hundred and twenty-five undergraduate and graduate students attending the University of Nebraska-Lincoln. Selected measures examined individuals’ demographics, physical health symptoms, medical provider-diagnosed severe/chronic health conditions, healthcare service use, help-seeking intentions, attenuated psychotic symptoms, and psychological wellbeing. Analyses included descriptive statistics, Pearson’s correlation coefficients, and T-tests. The study’s findings indicate that physical and attenuated psychotic symptoms are inversely correlated with help-seeking intentions, with healthcare service use correlated only with physical symptoms. These findings suggest that as symptoms and corresponding distress increase, people are less likely to engage in help-seeking behaviors, possibly related to barriers associated with symptoms such as decreased or low energy, avolition, or other challenges related to physical and mental health. Findings also indicate a need for further analysis of healthcare service use engagement and help-seeking behavior, including life- style and other health-related behaviors, to identify intervention targets to improve mental and physical health.
Keywords: serious mental illness, help-seeking behaviors, attenuated psychosi