516 research outputs found
Sources of Investment Inefficiency: The Case of Fixed-Asset Investment in China
This study attempts to measure the inefficiency associated with aggregate investment in a transitional economy. The inefficiency is decomposed into allocative and production inefficiency based on standard production theory. Allocative inefficiency is measured by disequilibrium investment demand. Institutional factors are then taken into consideration as possible explanatory variables of the disequilibrium. The resulting model is applied to Chinese provincial panel data. The main findings are: Chinese investment demand is strongly receptive to expansionary fiscal policies and inter-provincial network effects; and although there are signs of increasing allocative efficiency, the tendency of over-investment remains, even with improvements in production efficiency.Over-investment, Efficiency, Disequilibrium, Soft-budget constraint
Stress Level of a Classroom Instructors and Its Influence to Their Classroom Performance
In today’s education, teachers face numerous challenges. Among them, teacher stress level has a significant impact on classroom performance. This study aims to explore this influence. Classroom stress refers to the psychological and physiological tension teachers face due to various factors. It affects teachers’ communication with students, classroom management, and teaching quality. Factors contributing to teachers’ stress level include organizational, management, and individual factors. To address this, effective strategies are proposed: organizational interventions like optimizing resource allocation, reducing burdens, and providing psychological counseling; and individual interventions like self-adjustment, improving psychological quality, and teaching skills training. These strategies aim to reduce teacher stress, improve teaching quality, and contribute to education in our country
Feature Grouping and Sparse Principal Component Analysis
Sparse Principal Component Analysis (SPCA) is widely used in data processing
and dimension reduction; it uses the lasso to produce modified principal
components with sparse loadings for better interpretability. However, sparse
PCA never considers an additional grouping structure where the loadings share
similar coefficients (i.e., feature grouping), besides a special group with all
coefficients being zero (i.e., feature selection). In this paper, we propose a
novel method called Feature Grouping and Sparse Principal Component Analysis
(FGSPCA) which allows the loadings to belong to disjoint homogeneous groups,
with sparsity as a special case. The proposed FGSPCA is a subspace learning
method designed to simultaneously perform grouping pursuit and feature
selection, by imposing a non-convex regularization with naturally adjustable
sparsity and grouping effect. To solve the resulting non-convex optimization
problem, we propose an alternating algorithm that incorporates the
difference-of-convex programming, augmented Lagrange and coordinate descent
methods. Additionally, the experimental results on real data sets show that the
proposed FGSPCA benefits from the grouping effect compared with methods without
grouping effect.Comment: 21 pages, 5 figures, 2 table
Deciphering Charging Status, Absolute Quantum Efficiency, and Absorption Cross Section of MultiCarrier States in Single Colloidal Quantum Dot
Upon photo- or electrical-excitation, colloidal quantum dots (QDs) are often
found in multi-carrier states due to multi-photon absorption and photo-charging
of the QDs. While many of these multi-carrier states are observed in single-dot
spectroscopy, their properties are not well studied due to random
charging/discharging, emission intensity intermittency, and uncontrolled
surface defects of single QD. Here we report in-situ deciphering the charging
status, and precisely assessing the absorption cross section, and determining
the absolute emission quantum yield of mono-exciton and biexciton states for
neutral, positively-charged, and negatively-charged single core/shell CdSe/CdS
QD. We uncover very different photon statistics of the three charge states in
single QD and unambiguously identify their charge sign together with the
information of their photoluminescence decay dynamics. We then show their
distinct photoluminescence saturation behaviors and evaluated the absolute
values of absorption cross sections and quantum efficiencies of monoexcitons
and biexcitons. We demonstrate that addition of an extra hole or electron in a
QD changes not only its emission properties but also varies its absorption
cross section
Targeting Vacuolar H+-ATPases as a New Strategy against Cancer
Abstract
Growing evidence suggests a key role of tumor acidic microenvironment in cancer development, progression, and metastasis. As a consequence, the need for compounds that specifically target the mechanism(s) responsible for the low pH of tumors is increasing. Among the key regulators of the tumor acidic microenvironment, vacuolar H+-ATPases (V-ATPases) play an important role. These proteins cover a number of functions in a variety of normal as well as tumor cells, in which they pump ions across the membranes. We discuss here some recent results showing that a molecular inhibition of V-ATPases by small interfering RNA in vivo as well as a pharmacologic inhibition through proton pump inhibitors led to tumor cytotoxicity and marked inhibition of human tumor growth in xenograft models. These results propose V-ATPases as a key target for new strategies in cancer treatment. [Cancer Res 2007;67(22):10627–30
Improving Model Drift for Robust Object Tracking
Discriminative correlation filters show excellent performance in object
tracking. However, in complex scenes, the apparent characteristics of the
tracked target are variable, which makes it easy to pollute the model and cause
the model drift. In this paper, considering that the secondary peak has a
greater impact on the model update, we propose a method for detecting the
primary and secondary peaks of the response map. Secondly, a novel confidence
function which uses the adaptive update discriminant mechanism is proposed,
which yield good robustness. Thirdly, we propose a robust tracker with
correlation filters, which uses hand-crafted features and can improve model
drift in complex scenes. Finally, in order to cope with the current trackers'
multi-feature response merge, we propose a simple exponential adaptive merge
approach. Extensive experiments are performed on OTB2013, OTB100 and TC128
datasets. Our approach performs superiorly against several state-of-the-art
trackers while runs at speed in real time.Comment: 7 pages, 6 figures, 4 table
1,3-Dibenzyloxy-5-(bromomethyl)benzene
In the title compound, C21H19BrO2, the dihedral angles between the central benzene ring and the two peripheral rings are 50.28 (5) and 69.75 (2)°. The O—CH2 bonds lie in the plane of the central ring and adopt a syn–anti conformation
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