549 research outputs found
A Pragmatic Evaluation of an Academic Practicum\u27s Knowledge Transfer Process
Practicums are designed to provide on-the-job learning experience for the students in their chosen occupational field. But do students actually benefit from practicums? This manuscript investigates linkages between knowledge repository systems and knowledge transfer in database technology practicums. It examines the literature on knowledge transfer, develops an Action Research methodology, and presents results of a new study in database academic practicums. The study focuses on a graduate school database technology practicum at Denver-based Regis University. As a member of an academic practicum team with responsibilities involving database administrative support to a group of students and faculty, the researcher seeks to bring some data to bear on the types of methodologies utilized by past and current practicum teams over a twenty month period. The results of this investigation and the conditions that must be enabled for a practicum to effectively transfer knowledge will be presented
Venus Atmosphere Profile from a Maximum Entropy Principle
The variational method with constraints recently developed by Verkley and
Gerkema to describe maximum-entropy atmospheric profiles is generalized to
ideal gases but with temperature-dependent specific heats. In so doing, an
extended and non standard potential temperature is introduced that is well
suited for tackling the problem under consideration. This new formalism is
successfully applied to the atmosphere of Venus. Three well defined regions
emerge in this atmosphere up to a height of from the surface: the
lowest one up to about is adiabatic, a transition layer located at the
height of the cloud deck and finally a third region which is practically
isothermal.Comment: 6 pages, 3 figure
Neutrinos from Accreting Neutron Stars
The magnetospheres of accreting neutron stars develop electrostatic gaps with
huge potential drops. Protons and ions, accelerated in these gaps along the
dipolar magnetic field lines to energies greater than 100 TeV, can impact onto
a surrounding accretion disc. A proton-induced cascade so develops, and
-emission is produced from charged pion decays. Using GEANT4, a computer
code that tracks particles produced in high energy collisions, we have
calculated the resulting -spectrum with extensive disc shower simulations.
We show that the -spectrum produced out of the proton beam is a power law.
We use this result to propose accretion-powered X-ray binaries (with highly
magnetized neutron stars) as a new population of point-like -sources for
km-scale detectors, such as ICECUBE. As a particular example we discuss the
case of A0535+26. We show that ICECUBE should find A0535+26 to be a periodic
-source: one for which the formation and loss of its accretion disc can be
fully detected. Finally, we briefly comment on the possibility that smaller
telescopes, like AMANDA, could also detect A0535+26 by folding observations
with the orbital period.Comment: 7 pages, 5 figures. Updates to match accepted version in Astrophys.
OpenLab ESEV: novas aventuras no desenvolvimento de software
OpenLab ESEV is the Free Software project of the School of Education - Polytechnic
Institute of Viseu (ESEV). The project aims to establish a platform to aggregate activities that
foster the use of Free/Libre and Open Source Software (F/LOSS), Free Culture and more
flexible licenses for creative and educational purposes in the ESEV's domains of activity
(education, arts, media). OpenLab exists since 2009. It emerged in an environment
characterized by the lack of knowledge of the existing Libre alternatives and by work habits
exclusively built around proprietary software. Today, OpenLab activities are implemented within
four key areas of action: dissemination, training, support and production.
This paper presents two of the most important ongoing projects: Ottographer and
StudiozCollabPress. StudiozCollabPress is a customized version of a popular WordPress plugin
for project management that was developed to support short movie projects management.
We'll present its main features and results from real-case scenarios of use, specifically, finished
and ongoing 3D animation students' projects. Ottographer is a webcam time-lapse tool for
operating systems based on Debian GNU/Linux. Besides the main features, we'll present some
examples and suggestions for educational settings as well as for creative and educational
purposes.
Both projects are distributed as F/LOSS, meaning that they can be used, studied, and
modified without restrictions, as well as copied and redistributed in modified or unmodified form.
These projects might help us launch a new trend at our school community that we highly
antecipate: the development and sharing of our own tools
Autoimmune neurological conditions associated with Zika virus infection
Zika virus (ZIKV) is an emerging flavivirus rapidly spreading throughout the tropical Americas. mosquitoes is the principal way of transmission of the virus to humans. ZIKV can be spread by transplacental, perinatal, and body fluids. ZIKV infection is often asymptomatic and those with symptoms present minor illness after 3 to 12 days of incubation, characterized by a mild and self-limiting disease with low-grade fever, conjunctivitis, widespread pruritic maculopapular rash, arthralgia and myalgia. ZIKV has been linked to a number of central and peripheral nervous system injuries such as Guillain-Barré syndrome (GBS), transverse myelitis (TM), meningoencephalitis, ophthalmological manifestations, and other neurological complications. Nevertheless, mechanisms of host-pathogen neuro-immune interactions remain incompletely elucidated. This review provides a critical discussion about the possible mechanisms underlying the development of autoimmune neurological conditions associated with Zika virus infection
Deficit of Kcnma1 mRNA expression in the dentate gyrus of epileptic rats
Epileptogenesis in mesial temporal lobe epilepsy is determined by several factors including abnormalities in the expression and function of ion channels. Here, we report a long-lasting deficit in gene expression of Kcnma1 coding for the large-conductance calcium-activated potassium (BK, MaxiK) channel α-subunits after pilocarpine-induced status epilepticus. By using comparative realtime PCR, Taqman gene expression assays, and the delta-delta comparative threshold method we detected a significant reduction in Kcnma1 expression in microdissected dentate gyrus at different intervals after status epilepticus (24 h, 10 days, 1 month, and more than 2 months). BK channels are key regulators of neuronal excitability and transmitter release. Hence, defective Kcnma1 expression may play a critical role in the pathogenesis of mesial temporal lobe epilepsy
Differential changes in mGlu2 and mGlu3 gene expression following pilocarpine-induced status epilepticus: A comparative real-time PCR analysis
Group II metabotropic glutamate (mGlu II) receptors subtype 2 and 3 (mGlu2 and mGlu3) are subtle regulators of neuronal excitability and synaptic plasticity in the hippocampus. In recent years, researchers have investigated the potential neuroprotective and anticonvulsant effects of compounds acting on mGlu II receptors. However, abnormal expression and function of mGlu2 and mGlu3 have been reported in temporal lobe epilepsy, a phenomena that may limit the therapeutic effectiveness of these potentially new antiepileptic drugs. Here, we investigated seizure-induced changes in mGlu2 and mGlu3 mRNA following pilocarpine-inducted status epilepticus (SE) and subsequent epileptogenesis. Relative changes in gene expression were assessed by comparative analysis of quantitative real-time PCR (qrtPCR) by the delta–delta CT method. Pilocarpine-treated and control rats were sacrificed at different periods (24 h, 10 days, one month and more than two months) following SE. Total RNA was isolated from microdissected dentate gyrus and processed for RT-PCR and qrtPCR using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an endogenous control gene. Analysis of relative quantification (RQ) ratios of mGlu2 and mGlu3 mRNA expression revealed a significant down-regulation of both targets at 24 h after SE. Gene expression partially recovered at 10 days following SE reaching control levels at one month after SE. Two month after SE, mGlu2 mRNA expression was significantly down-regulated to ~ 41% of control expression whereas mGlu3 mRNA was comparable to control levels. Our data indicate that mGlu2 and mGlu3 expression is dynamically down-regulated or selectively enhanced during critical periods of epileptogenesis. Seizure-induced differential dysregulation of mGlu2 and mGlu3 receptors may affect the availability of these molecular targets for therapeutic compounds in epilepsy
Deficit of Kcnma1 mRNA expression in the dentate gyrus of epileptic rats
Epileptogenesis in mesial temporal lobe epilepsy is determined by several factors including abnormalities in the expression and function of ion channels. Here, we report a long-lasting deficit in gene expression of Kcnma1 coding for the large-conductance calcium-activated potassium (BK, MaxiK) channel alpha-subunits after pilocarpine-induced status epilepticus. By using comparative real-time PCR, Taqman gene expression assays, and the delta-delta comparative threshold method we detected a significant reduction in Kcnma1 expression in microdissected dentate gyrus at different intervals after status epilepticus (24 h, 10 days, 1 month, and more than 2 months). BK channels are key regulators of neuronal excitability and transmitter release. Hence, defective Kcnma1 expression may play a critical role in the pathogenesis of mesial temporal lobe epilepsy
Hurst Coefficient in long time series of population size: Model for two plant populations with different reproductive strategies
Can the fractal dimension of fluctuations in population size be used to estimate extinction risk? The problem with estimating this fractal dimension is that the lengths of the time series are usually too short for conclusive results. This study answered this question with long time series data obtained from an iterative competition model. This model produces competitive extinction at different perturbation intensities for two different germination strategies: germination of all seeds vs. dormancy in half the seeds. This provided long time series of 900 years and different extinction risks. The results support the hypothesis for the effectiveness of the Hurst coefficient for estimating extinction risk
Multiple and Precessing Collimated Outflows in the Planetary Nebula IC 4634
With its remarkable double-S shape, IC 4634 is an archetype of
point-symmetric planetary nebulae (PN). In this paper, we present a detailed
study of this PN using archival HST WFPC2 and ground-based narrow-band images
to investigate its morphology, and long-slit spectroscopic observations to
determine its kinematics and to derive its physical conditions and excitation.
The data reveal new structural components, including a distant string of knots
distributed along an arc-like feature 40"-60" from the center of the nebula, a
skin of enhanced [O III]/H-alpha ratio enveloping the inner shell and the
double-S feature, and a triple-shell structure. The spatio-kinematical study
also finds an equatorial component of the main nebula that is kinematically
independent from the bright inner S-shaped arc. We have investigated in detail
the bow shock-like features in IC 4634 and found that their morphological,
kinematical and emission properties are consistent with the interaction of a
collimated outflow with surrounding material. Indeed, the morphology and
kinematics of some of these features can be interpreted using a 3D numerical
simulation of a collimated outflow precessing at a moderate, time-dependent
velocity. Apparently, IC 4634 has experienced several episodes of
point-symmetric ejections oriented at different directions with the outer
S-shaped feature being related to an earlier point-symmetric ejection and the
outermost arc-like string of knots being the relic of an even much earlier
point-symmetric ejection. There is tantalizing evidence that the action of
these collimated outflows has also taken part in the shaping of the innermost
shell and inner S-shaped arc of IC 4634.Comment: 16 pages, 11 figures, accepted for publication in The Astrophysical
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