326 research outputs found
The role of the School Librarians as Information Literacy Specialists: a comparative study between Hong Kong, Shanghai, South Korea, Taipei, and Japan
Theme: The Educational Role of School Libraries in the M Generation主題 -- 學校圖書館在M世代的教育角色學校圖書館主任不僅是圖書館的管理人員,現今他們也擔負了教學、顧問、行政、資訊專家和資訊素養導師等角色;然而在亞洲國家,學校圖書館主任的這些角色與貢獻卻未被認定,其中尤以作為資訊素養專家的這個角色特別不受認可與重視。因此本研究的主要在分析比較學校圖書館主任作為資訊素養導師這個角色,在亞洲不同地區的情況與差異。本研究在香港、 日本、 上海、 韓國、及台北五個地區共收集了466 位學校圖書館主任的調查問卷。分析結果發現,圖書館主任在資訊素養方面擔當的範圍和參與度,台北和南韓方面的表現優於其他地區,尤其台北學校圖書館的人員編制和組織結構更傾向富裕和部門化。分析結果同時顯示學校圖書館主任進行資訊素養教育的數量,與他們和其他學科教師的協作,以及他們作為資訊顧問和對整體教學的貢獻成正比。此外學校圖書館主任提供參考服務的數量和程度以支援其他學科教師教學,是他們主要的貢獻。postprin
Expanding ART for Treatment and Prevention of HIV in South Africa: Estimated Cost and Cost-Effectiveness 2011-2050
Signal duration and the time scale dependence of signal integration in biochemical pathways
Signal duration (e.g. the time scales over which an active signaling
intermediate persists) is a key regulator of biological decisions in myriad
contexts such as cell growth, proliferation, and developmental lineage
commitments. Accompanying differences in signal duration are numerous
downstream biological processes that require multiple steps of biochemical
regulation. Here, we present an analysis that investigates how simple
biochemical motifs that involve multiple stages of regulation can be
constructed to differentially process signals that persist at different time
scales. We compute the dynamic gain within these networks and resulting power
spectra to better understand how biochemical networks can integrate signals at
different time scales. We identify topological features of these networks that
allow for different frequency dependent signal processing properties. Our
studies suggest design principles for why signal duration in connection with
multiple steps of downstream regulation is a ubiquitous control motif in
biochemical systems.Comment: 27 pages, 4 figure
Regulation of signal duration and the statistical dynamics of kinase activation by scaffold proteins
Scaffolding proteins that direct the assembly of multiple kinases into a
spatially localized signaling complex are often essential for the maintenance
of an appropriate biological response. Although scaffolds are widely believed
to have dramatic effects on the dynamics of signal propagation, the mechanisms
that underlie these consequences are not well understood. Here, Monte Carlo
simulations of a model kinase cascade are used to investigate how the temporal
characteristics of signaling cascades can be influenced by the presence of
scaffold proteins. Specifically, we examine the effects of spatially localizing
kinase components on a scaffold on signaling dynamics. The simulations indicate
that a major effect that scaffolds exert on the dynamics of cell signaling is
to control how the activation of protein kinases is distributed over time.
Scaffolds can influence the timing of kinase activation by allowing for kinases
to become activated over a broad range of times, thus allowing for signaling at
both early and late times. Scaffold concentrations that result in optimal
signal amplitude also result in the broadest distributions of times over which
kinases are activated. These calculations provide insights into one mechanism
that describes how the duration of a signal can potentially be regulated in a
scaffold mediated protein kinase cascade. Our results illustrate another
complexity in the broad array of control properties that emerge from the
physical effects of spatially localizing components of kinase cascades on
scaffold proteins.Comment: 12 pages, 6 figure
VCAM-1 and VLA-4 Modulate Dendritic Cell IL-12p40 Production in Experimental Visceral Leishmaniasis
Vascular cell adhesion molecule-1 (VCAM-1) interacts with its major ligand very late antigen-4 (VLA-4) to mediate cell adhesion and transendothelial migration of leukocytes. We report an important role for VCAM-1/VLA-4 interactions in the generation of immune responses during experimental visceral leishmaniasis caused by Leishmania donovani. Our studies demonstrate that these molecules play no direct role in the recruitment of leukocytes to the infected liver, but instead contribute to IL-12p40-production by splenic CD8+ dendritic cells (DC). Blockade of VCAM-1/VLA-4 interactions using whole antibody or anti-VCAM-1 Fab′ fragments reduced IL-12p40 mRNA accumulation by splenic DC 5 hours after L. donovani infection. This was associated with reduced anti-parasitic CD4+ T cell activation in the spleen and lowered hepatic IFNγ, TNF and nitric oxide production by 14 days post infection. Importantly, these effects were associated with enhanced parasite growth in the liver in studies with either anti-VCAM-1 or anti-VLA-4 antibodies. These data indicate a role for VCAM-1 and VLA-4 in DC activation during infectious disease
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Commentary: mechanistic considerations for associations between formaldehyde exposure and nasopharyngeal carcinoma
Occupational exposure to formaldehyde has been linked to nasopharyngeal carcinoma. To date, mechanistic explanations for this association have primarily focused on formaldehyde-induced cytotoxicity, regenerative hyperplasia and DNA damage. However, recent studies broaden the potential mechanisms as it is now well established that formaldehyde dehydrogenase, identical to S-nitrosoglutathione reductase, is an important mediator of cGMP-independent nitric oxide signaling pathways. We have previously described mechanisms by which formaldehyde can influence nitrosothiol homeostasis thereby leading to changes in pulmonary physiology. Considering evidences that nitrosothiols govern the Epstein-Barr virus infection cycle, and that the virus is strongly implicated in the etiology of nasopharyngeal carcinoma, studies are needed to examine the potential for formaldehyde to reactivate the Epstein-Barr virus as well as additively or synergistically interact with the virus to potentiate epithelial cell transformation
Overview of biologically digested leachate treatment using adsorption
Biological process is effective in treating most biodegradable organic matter present in leachate; however, a significant amount of ammonia, metals and refractory organic compounds may still remain in this biologically digested leachate. This effluent cannot be released to receiving bodies until the discharge limit is met. Several physical/chemical processes have been practiced as post-treatment to remove the remaining pollutants including coagulation–flocculation, oxidation and adsorption. Adsorption is often applied in leachate treatment as it enhances removal of refractory organic compounds. This chapter will focus on works related to adsorption as one of the commonly used methods to treat biologically digested leachate further down to acceptable discharge limit
Overview of biologically digested leachate treatment using adsorption
Biological process is effective in treating most biodegradable organic matter present in leachate; however, a significant amount of ammonia, metals and refractory organic compounds may still remain in this biologically digested leachate. This effluent cannot be released to receiving bodies until the discharge limit is met. Several physical/chemical processes have been practiced as post-treatment to remove the remaining pollutants including coagulation–flocculation, oxidation and adsorption. Adsorption is often applied in leachate treatment as it enhances removal of refractory organic compounds. This chapter will focus on works related to adsorption as one of the commonly used methods to treat biologically digested leachate further down to acceptable discharge limit
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