289 research outputs found
Precision Pion-Proton Elastic Differential Cross Sections at Energies Spanning the Delta Resonance
A precision measurement of absolute pi+p and pi-p elastic differential cross
sections at incident pion laboratory kinetic energies from T_pi= 141.15 to
267.3 MeV is described. Data were obtained detecting the scattered pion and
recoil proton in coincidence at 12 laboratory pion angles from 55 to 155
degrees for pi+p, and six angles from 60 to 155 degrees for pi-p. Single arm
measurements were also obtained for pi+p energies up to 218.1 MeV, with the
scattered pi+ detected at six angles from 20 to 70 degrees. A flat-walled,
super-cooled liquid hydrogen target as well as solid CH2 targets were used. The
data are characterized by small uncertainties, ~1-2% statistical and ~1-1.5%
normalization. The reliability of the cross section results was ensured by
carrying out the measurements under a variety of experimental conditions to
identify and quantify the sources of instrumental uncertainty. Our lowest and
highest energy data are consistent with overlapping results from TRIUMF and
LAMPF. In general, the Virginia Polytechnic Institute SM95 partial wave
analysis solution describes our data well, but the older Karlsruhe-Helsinki PWA
solution KH80 does not.Comment: 39 pages, 22 figures (some with quality reduced to satisfy ArXiv
requirements. Contact M.M. Pavan for originals). Submitted to Physical Review
Measurement of Inverse Pion Photoproduction at Energies Spanning the N(1440) Resonance
Differential cross sections for the process pi^- p -> gamma n have been
measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron
with the Crystal Ball multiphoton spectrometer. Measurements were made at 18
pion momenta from 238 to 748 MeV/c, corresponding to E_gamma for the inverse
reaction from 285 to 769 MeV. The data have been used to evaluate the gamma n
multipoles in the vicinity of the N(1440) resonance. We compare our data and
multipoles to previous determinations. A new three-parameter SAID fit yields 36
+/- 7 (GeV)^-1/2 X 10^-3 for the A^n_1/2 amplitude of the P_11.Comment: 14 pages, 8 figures, submitted to PR
Mechanically Assisted Exfoliation and Functionalization of Thermally Converted Graphene Sheets
Published versio
Rapid prototyping for biomedical engineering: current capabilities and Challenges
A new set of manufacturing technologies has emerged in the past decades to address market requirements in a customized way and to provide support for research tasks that require prototypes. These new techniques and technologies are usually referred to as rapid prototyping and manufacturing technologies, and they allow prototypes to be produced in a wide range of materials with remarkable precision in a couple of hours. Although they have been rapidly incorporated into product development methodologies, they are still under development, and their applications in bioengineering are continuously evolving. Rapid prototyping and manufacturing technologies can be of assistance in every stage of the development process of novel biodevices, to address various problems that can arise in the devices' interactions with biological systems and the fact that the design decisions must be tested carefully. This review focuses on the main fields of application for rapid prototyping in biomedical engineering and health sciences, as well as on the most remarkable challenges and research trends
Systemic neurotransmitter responses to clinically approved and experimental neuropsychiatric drugs.
Neuropsychiatric disorders are the third leading cause of global disease burden. Current pharmacological treatment for these disorders is inadequate, with often insufficient efficacy and undesirable side effects. One reason for this is that the links between molecular drug action and neurobehavioral drug effects are elusive. We use a big data approach from the neurotransmitter response patterns of 258 different neuropsychiatric drugs in rats to address this question. Data from experiments comprising 110,674 rats are presented in the Syphad database [ www.syphad.org ]. Chemoinformatics analyses of the neurotransmitter responses suggest a mismatch between the current classification of neuropsychiatric drugs and spatiotemporal neurostransmitter response patterns at the systems level. In contrast, predicted drug-target interactions reflect more appropriately brain region related neurotransmitter response. In conclusion the neurobiological mechanism of neuropsychiatric drugs are not well reflected by their current classification or their chemical similarity, but can be better captured by molecular drug-target interactions
Inclusive Jet and Hadron Suppression in a Multi-Stage Approach
We present a new study of jet interactions in the Quark-Gluon Plasma created
in high-energy heavy-ion collisions, using a multi-stage event generator within
the JETSCAPE framework. We focus on medium-induced modifications in the rate of
inclusive jets and high transverse momentum (high-) hadrons.
Scattering-induced jet energy loss is calculated in two stages: A high
virtuality stage based on the MATTER model, in which scattering of highly
virtual partons modifies the vacuum radiation pattern, and a second stage at
lower jet virtuality based on the LBT model, in which leading partons gain and
lose virtuality by scattering and radiation. Coherence effects that reduce the
medium-induced emission rate in the MATTER phase are also included. The
\trento\ model is used for initial conditions, and the (2+1)D VISHNU model is
used for viscous hydrodynamic evolution. Jet interactions with the medium are
modeled via 2-to-2 scattering with Debye screened potentials, in which the
recoiling partons are tracked, hadronized, and included in the jet clustering.
Holes left in the medium are also tracked and subtracted to conserve transverse
momentum. Calculations of the nuclear modification factor ()
for inclusive jets and high- hadrons are compared to
experimental measurements at RHIC and the LHC. Within this framework, we find
that two parameters for energy-loss, the coupling in the medium and the
transition scale between the stages of jet modification, suffice to
successfully describe these data at all energies, for central and semi-central
collisions, without re-scaling the jet transport coefficient .Comment: 33 pages, 23 figure
Multi-scale evolution of charmed particles in a nuclear medium
Parton energy-momentum exchange with the quark gluon plasma (QGP) is a
multi-scale problem. In this work, we calculate the interaction of charm quarks
with the QGP within the higher twist formalism at high virtuality and high
energy using the MATTER model, while the low virtuality and high energy portion
is treated via a (linearized) Boltzmann Transport (LBT) formalism. Coherence
effect that reduces the medium-induced emission rate in the MATTER model is
also taken into account. The interplay between these two formalisms is studied
in detail and used to produce a good description of the D-meson and charged
hadron nuclear modification factor RAA across multiple centralities. All
calculations were carried out utilizing the JETSCAPE framework
Elaborations, Revisions, Dissents: Alfred D. Chandler, Jr.’s., The Visible Hand after Twenty Years
Two decades have passed since the publication of 'The Visible Hand,' Alfred D. Chandler, Jr.'s, magisterial account of the rise of the modern business enterprise in the United States. Although Chandler's pathbreaking work has been widely hailed as a landmark in business history, only rarely has anyone considered systematically its influence on the large body of historical scholarship on related topics. This essay is intended to help fill this gap. It is divided into two sections. The first section reviews Chandler's argument, touches on the relationship of Chandler's oeuvre to his personal background, and locates 'The Visible Hand' in the context of American historical writing. The second considers how three groups of historians have responded to Chandler's ideas. These groups consist of champions who creatively elaborated on Chandler's intellectual agenda; critics who probed anomalies between Chandler's argument and their own research; and skeptics who rejected Chandler's analysis outright
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