2,514 research outputs found
Effects of Simulated Student Interaction on Student Perceptions of Teaching Presence
The purpose of this study was to explore the impact of the instructor posting in online discussions as a simulated student; particularly the impact simulated student interaction (SSI) had on the instructor/student relationship. Student perceptions were examined using a modified version of the Community of Inquiry (CoI) survey to determine what impact SSI had on teaching presence, cognitive presence, and social presence within the online classroom. The full 34 item CoI Survey was piloted in the summer of 2014 at a small comprehensive university located in northeast Texas. A factor analysis was conducted on the data and the top items from each factor in the instrument extracted. The resulting 17 item instrument demonstrated both validity and reliability. This modified CoI Survey was used in the fall of 2014 with three special education courses making up a control group and an intervention group in a pre-post experimental design. An ANOVA was performed to compare the results of the pre-course and post-course surveys by group. The ANOVA showed a statistically significant difference for all three factors for the intervention group between the pre- and post-course survey, while no significance between surveys was shown for the control group
Comparing Different Template Features for Recognizing People by Their Gait
To recognize people by their gait from a sequence of images, we have proposed a statistical approach which combined eigenspace transformation (EST) with canonical space transformation (CST) for feature transformation of spatial templates. This approach is used to reduce data dimensionality and to optimize the class separability of different gait sequences simultaneously. Good recognition rates have been achieved. Here, we incorporate temporal information from optical flows into three kinds of temporal templates and use them as features for gait recognition in addition to the spatial templates. The recognition performance for four kinds of template features has been evaluated in this paper. Experimental results show that spatial templates, horizontal-flow templates and the combined horizontal-flow and vertical-flow templates are better than vertical-flow templates for gait recognition
Dbl3 drives Cdc42 signaling at the apical margin to regulate junction position and apical differentiation
Epithelial cells develop morphologically characteristic apical domains that are bordered by tight junctions, the apicalâlateral border. Cdc42 and its effector complex Par6âatypical protein kinase c (aPKC) regulate multiple steps during epithelial differentiation, but the mechanisms that mediate process-specific activation of Cdc42 to drive apical morphogenesis and activate the transition from junction formation to apical differentiation are poorly understood. Using a small interfering RNA screen, we identify Dbl3 as a guanine nucleotide exchange factor that is recruited by ezrin to the apical membrane, that is enriched at a marginal zone apical to tight junctions, and that drives spatially restricted Cdc42 activation, promoting apical differentiation. Dbl3 depletion did not affect junction formation but did affect epithelial morphogenesis and brush border formation. Conversely, expression of active Dbl3 drove process-specific activation of the Par6âaPKC pathway, stimulating the transition from junction formation to apical differentiation and domain expansion, as well as the positioning of tight junctions. Thus, Dbl3 drives Cdc42 signaling at the apical margin to regulate morphogenesis, apicalâlateral border positioning, and apical differentiation
Generation of entangled coherent states via cross phase modulation in a double electromagnetically induced transparency regime
The generation of an entangled coherent state is one of the most important
ingredients of quantum information processing using coherent states. Recently,
numerous schemes to achieve this task have been proposed. In order to generate
travelling-wave entangled coherent states, cross phase modulation, optimized by
optical Kerr effect enhancement in a dense medium in an electromagnetically
induced transparency (EIT) regime, seems to be very promising. In this
scenario, we propose a fully quantized model of a double-EIT scheme recently
proposed [D. Petrosyan and G. Kurizki, {\sl Phys. Rev. A} {\bf 65}, 33833
(2002)]: the quantization step is performed adopting a fully Hamiltonian
approach. This allows us to write effective equations of motion for two
interacting quantum fields of light that show how the dynamics of one field
depends on the photon-number operator of the other. The preparation of a
Schr\"odinger cat state, which is a superposition of two distinct coherent
states, is briefly exposed. This is based on non-linear interaction via
double-EIT of two light fields (initially prepared in coherent states) and on a
detection step performed using a beam splitter and two photodetectors.
In order to show the entanglement of a generated entangled coherent state, we
suggest to measure the joint quadrature variance of the field. We show that the
entangled coherent states satisfy the sufficient condition for entanglement
based on quadrature variance measurement. We also show how robust our scheme is
against a low detection efficiency of homodyne detectors.Comment: 15 pages, 9 figures; extensively revised version; added Section
The local power of the gradient test
The asymptotic expansion of the distribution of the gradient test statistic
is derived for a composite hypothesis under a sequence of Pitman alternative
hypotheses converging to the null hypothesis at rate , being the
sample size. Comparisons of the local powers of the gradient, likelihood ratio,
Wald and score tests reveal no uniform superiority property. The power
performance of all four criteria in one-parameter exponential family is
examined.Comment: To appear in the Annals of the Institute of Statistical Mathematics,
this http://www.ism.ac.jp/editsec/aism-e.htm
Slow Light in Doppler Broadened Two level Systems
We show that the propagation of light in a Doppler broadened medium can be
slowed down considerably eventhough such medium exhibits very flat dispersion.
The slowing down is achieved by the application of a saturating counter
propagating beam that produces a hole in the inhomogeneous line shape. In
atomic vapors, we calculate group indices of the order of 10^3. The
calculations include all coherence effects.Comment: 6 pages, 5 figure
Clinical investigation of an outbreak of alveolitis and asthma in a car engine manufacturing plant
Background Exposure to metal working fluid (MWF) has been associated with outbreaks of EAA in the US, with bacterial contamination of MWF being a possible cause, but was uncommon in the UK. Twelve workers developed extrinsic allergic alveolitis (EAA) in a car engine manufacturing plant in the UK, presenting clinically between December 2003 and May 2004. This paper reports the subsequent epidemiological investigation of the whole workforce. This had three aims:-
âą To measure the extent of the outbreak by identifying other workers who may have developed EAA or other work-related respiratory diseases.
âą To provide case-detection so that those affected can be treated.
âą To provide epidemiological data to identify the cause of the outbreak.
Methods The outbreak was investigated in a three-phase cross-sectional survey of the workforce.
Phase I A respiratory screening questionnaire was completed by 808/836 workers (96.7%) in May 2004.
Phase II 481 employees with at least one respiratory symptom on screening and 50 asymptomatic controls were invited for investigation at the factory in June 2004. This included a questionnaire, spirometry and clinical opinion. 454/481(94.4%) responded along with 48/50(96%) controls. Workers were identified who needed further investigation and serial measurements of peak expiratory flow (PEF).
Phase III 162 employees were seen at the Birmingham Occupational Lung Disease clinic. 198 employees returned PEF records, including 141 of the 162 who attended for clinical investigation. Case definitions for diagnoses were agreed.
Results 87 workers (10.4% of workforce) met case definitions for occupational lung disease, comprising EAA(19), occupational asthma(74) and humidifier fever(7). 12 workers had more than one diagnosis. The peak onset of work-related breathlessness was Spring 2003. The proportion of workers affected was higher for those using metal working fluid (MWF) from a large sump(27.3%) compared with working all over the manufacturing area (7.9%) (OR=4.39,p<0.001). Two workers had positive specific provocation tests to the used but not the unused MWF solution.
Conclusions Extensive investigation of the outbreak of EAA detected a large number of affected workers, not only with EAA but also occupational asthma. This is the largest reported outbreak in Europe. Mist from used MWF is the likely cause. In workplaces using MWF, there is a need to carry out risk assessments, to monitor and maintain fluid quality, to control mist and to carry out respiratory health surveillance
Field Theory And Second Renormalization Group For Multifractals In Percolation
The field-theory for multifractals in percolation is reformulated in such a
way that multifractal exponents clearly appear as eigenvalues of a second
renormalization group. The first renormalization group describes geometrical
properties of percolation clusters, while the second-one describes electrical
properties, including noise cumulants. In this context, multifractal exponents
are associated with symmetry-breaking fields in replica space. This provides an
explanation for their observability. It is suggested that multifractal
exponents are ''dominant'' instead of ''relevant'' since there exists an
arbitrary scale factor which can change their sign from positive to negative
without changing the Physics of the problem.Comment: RevTex, 10 page
Overexpression of mineralocorticoid receptors does not affect memory and anxiety-like behavior in female mice
A theoretical approach for the electrochemical characterization of ciliary epithelium
The ciliary epithelium (CE) is the primary site of aqueous humor (AH) production, which
results from the combined action of ultrafiltration and ionic secretion. Modulation of ionic secretion
is a fundamental target for drug therapy in glaucoma, and therefore it is important to identify the
main factors contributing to it. Since several ion transporters have been hypothesized as relevant
players in CE physiology, we propose a theoretical approach to complement experimental methods
in characterizing their role in the electrochemical and fluid-dynamical conditions of CE. As a first
step, we compare two model configurations that differ by (i) types of transporters included for
ion exchange across the epithelial membrane, and by (ii) presence or absence of the intracellular
production of carbonic acid mediated by the carbonic anhydrase enzyme. The proposed model
configurations do not include neurohumoral mechanisms such as P2Y receptor dependent, cAMP
or calcium dependent pathways, which occur in the ciliary epithelium bilayer and influence the
activity of ion transporters, pumps and channels present in the cell membrane. Results suggest
that one of the two configurations predicts sodium and potassium intracellular concentrations and
transmembrane potential much more accurately than the other. Because of its quantitative prediction
power, the proposed theoretical approach may help relate phenomena at the cellular scale, that cannot
be accessed clinically, with phenomena occuring at the scale of the whole eye, for which clinical
assessment is feasible
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