683 research outputs found
Cyclic AMP-specific phosphodiesterase, PDE8A1, is activated by protein kinase A-mediated phosphorylation
The cyclic AMP-specific phosphodiesterase PDE8 has been shown to play a pivotal role in important processes such as steroidogenesis, T cell adhesion, regulation of heart beat and chemotaxis. However, no information exists on how the activity of this enzyme is regulated. We show that under elevated cAMP conditions, PKA acts to phosphorylate PDE8A on serine 359 and this action serves to enhance the activity of the enzyme. This is the first indication that PDE8 activity can be modulated by a kinase, and we propose that this mechanism forms a feedback loop that results in the restoration of basal cAMP levels. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserve
Competency-Based Approach to Information Systems Program Development: Guidance from the MSIS 2016 Global Competence Model
The panel has three objectives: First, it will present multiple perspectives on competency-driven approaches to developing and evaluating degree programs in Information Systems and compare the competency-driven approach to earlier, teaching topic or body of knowledge –driven approaches. Second, it will introduce the (nearly) completed version of the MSIS 2016 global competency model to the members of the global IS community and celebrate IS community’s efforts to improve the quality of graduate education. Third, the panel will discuss the essential role the competency-driven approach has as a foundation of MSIS 2016
Agency Conflicts and Corporate Payout Policies: A Global Study
We investigate the roles of firm and country level agency conflicts in determining corporate payout policies. Based on a large sample of 29,610 firms in 43 countries from 2001 to 2006, we find that in high protection countries, investors are able to use their legal powers to extract cash from firms but their ability to do so can be substantially hindered when agency costs at the firm level are high. In poor protection countries, investors can seek refuge in firm level governance mechanisms to curb agency conflicts, suggesting a substitution between country and firm level investor protection. Finally, compared to repurchases, we find dividends are more likely to be the sole method of payout in high protection countries and in less closely held firms
Agency Conflicts and Corporate Payout Policies: A Global Study
We investigate the roles of firm and country level agency conflicts in determining corporate payout policies. Based on a large sample of 29,610 firms in 43 countries from 2001 to 2006, we find that in high protection countries, investors are able to use their legal powers to extract cash from firms but their ability to do so can be substantially hindered when agency costs at the firm level are high. In poor protection countries, investors can seek refuge in firm level governance mechanisms to curb agency conflicts, suggesting a substitution between country and firm level investor protection. Finally, compared to repurchases, we find dividends are more likely to be the sole method of payout in high protection countries and in less closely held firms
Transport in rough self-affine fractures
Transport properties of three-dimensional self-affine rough fractures are
studied by means of an effective-medium analysis and numerical simulations
using the Lattice-Boltzmann method. The numerical results show that the
effective-medium approximation predicts the right scaling behavior of the
permeability and of the velocity fluctuations, in terms of the aperture of the
fracture, the roughness exponent and the characteristic length of the fracture
surfaces, in the limit of small separation between surfaces. The permeability
of the fractures is also investigated as a function of the normal and lateral
relative displacements between surfaces, and is shown that it can be bounded by
the permeability of two-dimensional fractures. The development of channel-like
structures in the velocity field is also numerically investigated for different
relative displacements between surfaces. Finally, the dispersion of tracer
particles in the velocity field of the fractures is investigated by analytic
and numerical methods. The asymptotic dominant role of the geometric
dispersion, due to velocity fluctuations and their spatial correlations, is
shown in the limit of very small separation between fracture surfaces.Comment: submitted to PR
Non-Linear Vibrations in Nuclei
We have perfomed Time Dependant Hartree-Fock (TDHF) calculations on the non
linear response of nuclei. We have shown that quadrupole (and dipole) motion
produces monopole (and quadrupole) oscillations in all atomic nuclei. We have
shown that these findings can be interpreted as a large coupling between one
and two phonon states leading to large anharmonicities.Comment: 4 pages, 3 figure
The Role of the Pediatric Nurse Practitioner in the Comprehensive Management of Pediatric Oncology Patients in the Inpatient Setting
The role of the pediatric nurse practitioner (PNP) in the comprehensive management of pediatric oncology patients in the inpatient setting was examined at a large tertiary teaching hospital. This article shows role responsibilities including new diagnosis teaching, procedures, routine chemotherapy, patients' comprehensive medical management, coordination of nursing care across settings, phone triage, and professional development. A PNP's typical day is highlighted to illustrate the innovative merging of traditional ambulatory care roles with that of the PNP as a comprehensive manager of pediatric oncology patients in the inpatient setting. This role provides a more seamless care experience and provides critical links in the delivery of health care to pediatric oncology patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68349/2/10.1177_104345429901600202.pd
Cooling Properties of Cloudy Bag Strange Stars
As the chiral symmetry is widely recognized as an important driver of the
strong interaction dynamics, current strange stars models based on MIT bag
models do not obey such symmetry. We investigate properties of bare strange
stars using the Cloudy Bag Model, in which a pion cloud coupled to the
quark-confining bag is introduced such that chiral symmetry is conserved. We
find that in this model the decay of pions is a very efficient cooling way. In
fact it can carry out most the thermal energy in a few milliseconds and
directly convert them into 100MeV photons via pion decay. This may be a very
efficient -ray burst mechanism. Furthermore, the cooling behavior may
provide a possible way to distinguish a compact object between a neutron star,
MIT strange star and Cloudy Bag strange star in observations.Comment: 23 pages, 14 figures, accepted by Astroparticle Physics, abstract
appeared here has been shortene
A Hadron Blind Detector for the PHENIX Experiment
A novel Hadron Blind Detector (HBD) has been developed for an upgrade of the
PHENIX experiment at RHIC. The HBD will allow a precise measurement of
electron-positron pairs from the decay of the light vector mesons and the
low-mass pair continuum in heavy-ion collisions. The detector consists of a 50
cm long radiator filled with pure CF4 and directly coupled in a windowless
configuration to a triple Gas Electron Multiplier (GEM) detector with a CsI
photocathode evaporated on the top face of the first GEM foil.Comment: 4 pages, 3 figures, Quark Matter 2005 conference proceeding
Formation of superdense hadronic matter in high energy heavy-ion collisions
We present the detail of a newly developed relativistic transport model (ART
1.0) for high energy heavy-ion collisions. Using this model, we first study the
general collision dynamics between heavy ions at the AGS energies. We then show
that in central collisions there exists a large volume of sufficiently
long-lived superdense hadronic matter whose local baryon and energy densities
exceed the critical densities for the hadronic matter to quark-gluon plasma
transition. The size and lifetime of this matter are found to depend strongly
on the equation of state. We also investigate the degree and time scale of
thermalization as well as the radial flow during the expansion of the
superdense hadronic matter. The flow velocity profile and the temperature of
the hadronic matter at freeze-out are extracted. The transverse momentum and
rapidity distributions of protons, pions and kaons calculated with and without
the mean field are compared with each other and also with the preliminary data
from the E866/E802 collaboration to search for experimental observables that
are sensitive to the equation of state. It is found that these inclusive,
single particle observables depend weakly on the equation of state. The
difference between results obtained with and without the nuclear mean field is
only about 20\%. The baryon transverse collective flow in the reaction plane is
also analyzed. It is shown that both the flow parameter and the strength of the
``bounce-off'' effect are very sensitive to the equation of state. In
particular, a soft equation of state with a compressibility of 200 MeV results
in an increase of the flow parameter by a factor of 2.5 compared to the cascade
case without the mean field. This large effect makes it possible to distinguish
the predictions from different theoretical models and to detect the signaturesComment: 55 pages, latex, + 39 figures available upon reques
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