187 research outputs found

    Content and construct validity of the Early Childhood Physical Environment Rating Scale (ECPERS)

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    The Early Childhood Physical Environment Rating Scale (ECPERS) has been designed to assess the quality of the physical environment of early childhood educational facilities. The purpose of the current research was to examine the content and construct validity of the scale. With regard to content validity, the vast majority of items (93%) in the scale were found to be important to very important by a diverse panel of 12 experts. Construct validity was measured as the degree of agreement between expert's global evaluation of a center and by using the 142-item ECPERS scale. The data from 13 experts assessing 13 different centers across Australia and New Zealand showed a very high correlation between expert's judgements and ECPERS score (r=0.85). The results indicate that ECPERS is a valid instrument for the measurement of the quality of the physical environment of early childhood centers relative to the potential for child development and learning

    Effect of the spin-orbit interaction and the electron phonon coupling on the electronic state in a silicon vacancy

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    The electronic state around a single vacancy in silicon crystal is investigated by using the Green's function approach. The triply degenerate charge states are found to be widely extended and account for extremely large elastic softening at low temperature as observed in recent ultrasonic experiments. When we include the LS coupling λSi\lambda_{\rm Si} on each Si atom, the 6-fold spin-orbital degeneracy for the V+V^{+} state with the valence +1 and spin 1/2 splits into Γ7\Gamma_{7} doublet groundstates and Γ8\Gamma_{8} quartet excited states with a reduced excited energy of O(λSi/10)O(\lambda_{\rm Si}/10). We also consider the effect of couplings between electrons and Jahn-Teller phonons in the dangling bonds within the second order perturbation and find that the groundstate becomes Γ8\Gamma_{8} quartet which is responsible for the magnetic-field suppression of the softening in B-doped silicon.Comment: 4 pages, 2 figure

    Predicting urban surface roughness aerodynamic parameters using random forest

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    The surface roughness aerodynamic parameters z0 (roughness length) and d (zero-plane displacement height) are vital to the accuracy of the Monin–Obukhov similarity theory. Deriving improved urban canopy parameterization (UCP) schemes within the conventional framework remains mathematically challenging. The current study explores the potential of a machine-learning (ML) algorithm, a random forest (RF), as a complement to the traditional UCP schemes. Using large-eddy simulation and ensemble sampling, in combination with nonlinear least squares regression of the logarithmic-layer wind profiles, a dataset of approximately 4.5 × 10³ samples is established for the aerodynamic parameters and the morphometric statistics, enabling the training of the ML model. While the prediction for d is not as good as the UCP after Kanda et al., the performance for z₀ is notable. The RF algorithm also categorizes z₀ and d with an exceptional performance score: the overall bell-shaped distributions are well predicted, and the ±0.5σ category (i.e., the 38% percentile) is competently captured (37.8% for z₀ and 36.5% for d). Among the morphometric features, the mean and maximum building heights (Have and Hmax, respectively) are found to be of predominant influence on the prediction of z₀ and d. A perhaps counterintuitive result is the considerably less striking importance of the building-height variability. Possible reasons are discussed. The feature importance scores could be useful for identifying the contributing factors to the surface aerodynamic characteristics. The results may shed some light on the development of ML-based UCP for mesoscale modeling

    The Angular Trispectra of CMB Temperature and Polarization

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    We develop the formalism necessary to study four-point functions of the cosmic microwave background (CMB) temperature and polarization fields. We determine the general form of CMB trispectra, with the constraints imposed by the assumption of statistical isotropy of the CMB fields, and derive expressions for their estimators, as well as their Gaussian noise properties. We apply these techniques to initial non-Gaussianity of a form motivated by inflationary models. Due to the large number of four-point configurations, the sensitivity of the trispectra to initial non-Gaussianity approaches that of the temperature bispectrum at high multipole moment. These trispectra techniques will also be useful in the study of secondary anisotropies induced for example by the gravitational lensing of the CMB by the large scale structure of the universe.Comment: 16 pages, 4 figures; typographical errors correcte

    Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

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    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology

    ISSUES IN HIGH-RESOLUTION ATMOSPHERIC MODELING IN COMPLEX TOPOGRAPHY --THE HiRCoT WORKSHOP

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    During the past years the atmospheric modeling community, both from the application and pure research perspectives, has been facing the challenge of high resolution numerical modeling in places with complex topography. In February 2012, as a result of the collaborative efforts of the Institute of Meteorology of the University of Natural Resources and Life Sciences (BOKUMet), the Arctic Region Supercomputing Center (ARSC), the Institute of Meteorology and Geophysics of the University of Innsbruck (IMG) and the enthusiasm of the scientific community, the HiRCoT workshop was held in Vienna, Austria. HiRCoT objectives were to: 1) Identify the problems encountered with numerical modeling at grid spacing lower than 1 km over complex terrain, that is, understand the key areas that are troublesome and formulate the key questions about them; 2) Map out possibilities on how to address these issues; 3) Allow the researchers to discuss the issues on a shared platform (online through a wikipage and face-to-face). This manuscript presents an overview of the topics and research priorities discussed in the workshop

    Ferroquadrupole ordering and Gamma_5 rattling motion in clathrate compound Ce_3Pd_20Ge_6

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    Lattice effects in a cerium based clathrate compound Ce_3Pd_20Ge_6 with a cubic Cr_23C_6-type structure have been investigated by ultrasonic and thermal expansion measurements. Elastic softenings of (C_11-C_12)/2 and C_44 proportional to the reciprocal temperature 1/T above T_Q1 = 1.25 K are well described in terms of the quadrupole susceptibility for the ground state Gamma_8 quartet. A huge softening of 50 % in (C_11-C_12)/2 and a spontaneous expansion DL/L = 1.9x10^-4 along the [001] direction in particular indicate the ferroquadrupole ordering of O_2^0 below T_Q1. The elastic anomalies associated with the antiferromagnetic ordering at T_N2 = 0.75 K and the incommensurate antiferromagnetic ordering are also found. Notable frequency dependence of C_44 around 10 K is accounted for by the Debye-type dispersion indicating a Gamma_5 rattling motion of an off-center Ce ion along the [111] direction with eight fractionally occupied positions around the 4a site in a cage. The thermally activated Gamma_5 rattling motion obeying a relaxation time t = t_0exp(E/k_BT) with an attempt time t_0 = 3.1x10^-11 sec and an activation energy E = 70 K dies out with decreasing temperature, and then the off-center tunneling state of Ce ion in the 4a-site cage will appear at low temperatures.Comment: 11 pages, 15 figures, to be published on Phys. Rev.

    Penguin-Diagram Induced BKXϕB \rightarrow K_X\phi Decays in the Standard Model and in the Two-Higgs-Doublet Model

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    We systematically analyse the gluonic penguin-induced charmless decays B \ra K_X\phi(KXK_X denotes the meson state sqˉ  (q=u or d)s\bar q \;(q=u\ {\rm or}\ d) ), in the standard model and the two-Higgs-doublet model. These processes, being induced at one-loop level, are of great importance in measuring the virtual top quark effect in the standard model, and also in searching for the non-standard signals in the low energy region. It is shown that the QCD effect is also significant in these processes, as in the weak radiative processes B \ra X_s \gamma. We also show that the charged Higgs contribution can not provide sizable enhancements for the decays B \ra K_X\phi, in contrast to the decays B \ra K_X\gamma. It is also found that processes such as B \ra K_1(1400)\phi and B \ra K(1460)\phi have large branching fractions among B \ra K_X\phi decays.Comment: 18pages, Latex. Paper (Hayashi, Takemi et al. AUE-02-93) is replaced with reviced version Jan 1994 and aloso the title is change

    Spatial Metrics of Interaction between CD163-Positive Macrophages and Cancer Cells and Progression-Free Survival in Chemo-Treated Breast Cancer

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    Tumor-associated macrophages (TAMs) promote progression of breast cancer and other solid malignancies via immunosuppressive, pro-angiogenic and pro-metastatic effects. Tumor-promoting TAMs tend to express M2-like macrophage markers, including CD163. Histopathological assessments suggest that the density of CD163-positive TAMs within the tumor microenvironment is associated with reduced efficacy of chemotherapy and unfavorable prognosis. However, previous analyses have required research-oriented pathologists to visually enumerate CD163+ TAMs, which is both laborious and subjective and hampers clinical implementation. Objective, operator-independent image analysis methods to quantify TAM-associated information are needed. In addition, since M2-like TAMs exert local effects on cancer cells through direct juxtacrine cell-to-cell interactions, paracrine signaling, and metabolic factors, we hypothesized that spatial metrics of adjacency of M2-like TAMs to breast cancer cells will have further information value. Immunofluorescence histo-cytometry of CD163+ TAMs was performed retrospectively on tumor microarrays of 443 cases of invasive breast cancer from patients who subsequently received adjuvant chemotherapy. An objective and automated algorithm was developed to phenotype CD163+ TAMs and calculate their density within the tumor stroma and derive several spatial metrics of interaction with cancer cells. Shorter progression-free survival was associated with a high density of CD163+ TAMs, shorter median cancer-to-CD163+ nearest neighbor distance, and a high number of either directly adjacent CD163+ TAMs (within juxtacrine proximity \u3c12 µm to cancer cells) or communicating CD163+ TAMs (within paracrine communication distance \u3c250 µm to cancer cells) after multivariable adjustment for clinical and pathological risk factors and correction for optimistic bias due to dichotomization
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