210 research outputs found
Thermal model at RHIC, part II: elliptic flow and HBT radii
We continue the analysis of the preceding talk with a discussion of the
elliptic flow and the HBT pion correlation radii. It is shown that the thermal
model can be extended to describe these phenomena. The description of the
elliptic flow involves an appropriate deformation of the freeze-out
hypersurface and flow velocity. The obtained results agree reasonably with the
data for soft (< 2 GeV) transverse momenta. For the pionic HBT correlation
radii the experimental feature that R_out/R_side ~ 1 is naturally obtained. The
reproduction of individual R_side and R_out can be achieved with the inclusion
of the excluded volume corrections, which effectively increase the radii by
\~30%.Comment: Talk presented at II International Workshop on Hadron Physics, 25-29
September 2002, Coimbra, Portugal (10 pages
pion-rho-omega vertex in nuclear matter
Medium modifications of the pion-omega-rho vertex are analyzed in context of
the omega -> pi gamma* and rho -> pi gamma* decays in nuclear matter. A
relativistic hadronic model with mesons, nucleons, and Delta(1232)isobars is
applied. A substantial increase of the widths for the decays omega -> pi gamma*
and rho -> pi gamma* is found for photon virtualities in the range 0.3-0.6 GeV.
This enhancement has a direct importance for the description of dilepton yields
obtained in relativistic heavy-ion collisions.Comment: 6 pages, to appear in Proc. 2nd International Symposium on Quantum
Theory and Symmetries, Cracow, 18-21 July 200
Dowling-Degos Disease: Case Report and Review of the Literature
Dowling-Degos disease (DDD) is an unusual pigmentary disorder usually caused by mutations in keratin 5. A 44-year-old woman in good general health presented due to the recent appearance of numerous pigmented macules on her axillary and anogenital skin. A biopsy showed lacy, finger-like epidermal extensions into the dermis which were heavily pigmented and associated with tiny cysts or dilated follicles. We view DDD as part of a spectrum of disorders which are morphologically related but vary in location and time of expression. In addition, both the clinical and histological differential diagnostic considerations are extensive. Copyright (C) 2010 S. Karger AG, Base
Morphometric changes in the corpus luteum of pregnant hypokinetic rats
The aim of this work was to study the influence of hypokinetic conditions on
the ovary and corpus luteum of pregnant rats. The rats were kept in hypokinetic
conditions for 5 days in the period between the 13th and 18th days of
pregnancy. A three-dimensional reconstruction of the ovary and corpora lutea
and also a stereological evaluation of the luteal cells and their nuclei were
performed using serially cut material. Hypokinesia caused a decrease in the
mean volume of the ovary and individual corpus luteum and in the total volume
of corpora lutea per ovary in immobilised animals as compared to the
control. Moreover, a decrease was observed in the mean number of luteal
cells and an increase in the size of these cells, as well as in the mean volume
fraction of their nuclei. These results indicate that immobilisation of pregnant
rats for 5 days considerably influences the morphology of the corpus luteum
and luteal cells
Self-diffusion and shear viscosity for the TIP4P/Ice water model
With an ever-increasing interest in water properties, many intermolecular
force fields have been proposed to describe the behavior of water.
Unfortunately, good models for liquid water usually cannot provide
simultaneously an accurate melting point for ice. For this reason, the
TIP4P/Ice model was developed at targeting the melting point, and has become
the preferred choice for simulating ice at coexistence. Unfortunately,
available data for its dynamic properties in the liquid state are scarce.
Therefore, we demonstrate a series of simulations aimed at the calculation of
transport coefficients for the TIP4P/Ice model over a large range of
thermodynamic conditions, ranging from K to K for the
temperature and from to MPa for the pressure. We have found that
the self-diffusion (shear viscosity) exhibits smaller (increased) values than
TIP4P/2005 and experiments. However, rescaling the temperature with respect to
the triple point temperature as in a corresponding states plot we find
TIP4P/Ice compares very well with TIP4P/2005 and to experiment. Such
observations allow us to infer that despite the different original purposes of
these two models examined here, one can benefit from a vast number of reports
regarding the behavior of transport coefficients for the TIP4P/2005 model and
utilize them following the routine described in this paper
Computing and fabricating multilayer models
We present a method for automatically converting a digital 3D model into a multilayer model: a parallel stack of high-resolution 2D images embedded within a semi-transparent medium. Multilayer models can be produced quickly and cheaply and provide a strong sense of an object's 3D shape and texture over a wide range of viewing directions. Our method is designed to minimize visible cracks and other artifacts that can arise when projecting an input model onto a small number of parallel planes, and avoid layer transitions that cut the model along important surface features. We demonstrate multilayer models fabricated with glass and acrylic tiles using commercially available printers
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Chopper: Partitioning models into 3D-printable parts
3D printing technology is rapidly maturing and becoming ubiquitous. One of the remaining obstacles to wide-scale adoption is that the object to be printed must fit into the working volume of the 3D printer. We propose a framework, called Chopper, to decompose a large 3D object into smaller parts so that each part fits into the printing volume. These parts can then be assembled to form the original object. We formulate a number of desirable criteria for the partition, including assemblability, having few components, unobtrusiveness of the seams, and structural soundness. Chopper optimizes these criteria and generates a partition either automatically or with user guidance. Our prototype outputs the final decomposed parts with customized connectors on the interfaces. We demonstrate the effectiveness of Chopper on a variety of non-trivial real-world objects.National Science Foundation (U.S.) (Grant CCF-1012147)National Science Foundation (U.S.) (Grant IIS-1116296)Intel Corporation (Science and Technology Center for Visual Computing
Real-Time Volumetric Shadows using 1D Min-Max Mipmaps
Light scattering in a participating medium is responsible for several important effects we see in the natural world. In the presence of occluders, computing single scattering requires integrating the illumination scattered towards the eye along the camera ray, modulated by the visibility towards the light at each point. Unfortunately, incorporating volumetric shadows into this integral, while maintaining real-time performance, remains challenging.
In this paper we present a new real-time algorithm for computing volumetric shadows in single-scattering media on the GPU. This computation requires evaluating the scattering integral over the intersections of camera rays with the shadow map, expressed as a 2D height field. We observe that by applying epipolar rectification to the shadow map, each camera ray only travels through a single row of the shadow map (an epipolar slice), which allows us to find the visible segments by considering only 1D height fields. At the core of our algorithm is the use of an acceleration structure (a 1D minmax mipmap) which allows us to quickly find the lit segments for all pixels in an epipolar slice in parallel. The simplicity of this data structure and its traversal allows for efficient implementation using only pixel shaders on the GPU
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