35,269 research outputs found
New Terms for the Compact Form of Electroweak Chiral Lagrangian
The compact form of the electroweak chiral Lagrangian is a reformulation of
its original form and is expressed in terms of chiral rotated electroweak gauge
fields, which is crucial for relating the information of underlying theories to
the coefficients of the low-energy effective Lagrangian. However the compact
form obtained in previous works is not complete. In this letter we add several
new chiral invariant terms to it and discuss the contributions of these terms
to the original electroweak chiral Lagrangian.Comment: 3 pages, references adde
Quantum Spin Hall and Quantum Anomalous Hall States Realized in Junction Quantum Wells
Both quantum spin Hall and quantum anomalous Hall states are novel states of
quantum matter with promising applications. We propose junction quantum wells
comprising II-VI, III-V or IV semiconductors as a large class of new materials
realizing the quantum spin Hall state. Especially, we find that the bulk band
gap for the quantum spin Hall state can be as large as 0.1 eV. Further more,
magnetic doping would induce the ferromagnetism in these junction quantum wells
due to band edge singularities in the band-inversion regime and to realize the
quantum anomalous Hall state.Comment: 5 pages, 4 figure
Hydrothermal synthesis of α-MnO<inf>2</inf> and β-MnO <inf>2</inf> nanorods as high capacity cathode materials for sodium ion batteries
Two types of MnO2 polymorphs, α-MnO2 and β-MnO2 nanorods, have been synthesized by a hydrothermal method. Their crystallographic phases, morphologies, and crystal structures were characterized by XRD, FESEM and TEM analysis. Different exposed crystal planes have been identified by TEM. The electrochemical properties of α-MnO 2 and β-MnO2 nanorods as cathode materials in Na-ion batteries were evaluated by galvanostatic charge/discharge testing. Both α-MnO2 and β-MnO2 nanorods achieved high initial sodium ion storage capacities of 278 mA h g-1 and 298 mA h g-1, respectively. β-MnO2 nanorods exhibited a better electrochemical performance such as good rate capability and cyclability than that of α-MnO2 nanorods, which could be ascribed to a more compact tunnel structure of β-MnO2 nanorods. Furthermore, the one-dimensional architecture of nanorods could also contribute to facile sodium ion diffusion in the charge and discharge process. © The Royal Society of Chemistry 2013
SnO<inf>2</inf>@graphene nanocomposites as anode materials for Na-ion batteries with superior electrochemical performance
An in situ hydrothermal synthesis approach has been developed to prepare SnO2@graphene nanocomposites. The nanocomposites exhibited a high reversible sodium storage capacity of above 700 mA h g-1 and excellent cyclability for Na-ion batteries. In particular, they also demonstrated a good high rate capability for reversible sodium storage. © 2013 The Royal Society of Chemistry
Hydrothermal synthesis of I?-MnO2 and I?-MnO2 nanorods as high capacity cathode materials for sodium ion batteries
Two types of MnO2 polymorphs, I?-MnO2 and I?-MnO2 nanorods, have been synthesized by a hydrothermal method. Their crystallographic phases, morphologies, and crystal structures were characterized by XRD, FESEM and TEM analysis. Different exposed crystal planes have been identified by TEM. The electrochemical properties of I?-MnO2 and I?-MnO2 nanorods as cathode materials in Na-ion batteries were evaluated by galvanostatic charge/discharge testing. Both I?-MnO2 and I?-MnO2 nanorods achieved high initial sodium ion storage capacities of 278 mA h ga??1 and 298 mA h ga??1, respectively. I?-MnO2 nanorods exhibited a better electrochemical performance such as good rate capability and cyclability than that of I?-MnO2 nanorods, which could be ascribed to a more compact tunnel structure of I?-MnO2 nanorods. Furthermore, the one-dimensional architecture of nanorods could also contribute to facile sodium ion diffusion in the charge and discharge process
4D dynamic management for construction planning and resource utilization
Author name used in this publication: K. W. Chau2003-2004 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Influence of Isentropic Mixing on Seasonal Ozone Variations in the Lower Stratosphere and Upper Troposphere
[1] The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment II ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is ∼118 ± 61 × 109 kg yr−1 globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer
The challenge of acute-stroke management: does telemedicine offer a solution?
<p><b>Background:</b> Several studies have described successful experiences with the use of telemedicine in acute stroke. The objective of this study was to assess the feasibility, acceptability, and treatment delivery reliability, of telemedicine systems for the clinical and radiological assessment, and management of acute-stroke patients.</p>
<p><b>Summary of Review:</b> A systematic review of the literature was carried out. Studies were included if they met the following criteria: (1) study population included participants with a diagnosis of suspected acute stroke, (2) intervention included the use of telemedicine systems to aid assessment, diagnosis, or treatment in acute stroke, and (3) outcomes measured related to feasibility in clinical practice, acceptability to patients, carers, and staff, reliability of telemedicine systems, and effectiveness in delivering treatment, especially tissue plasminogen activator (tPA). Overall, 17 relevant non-randomised studies reported that telemedicine systems were feasible and acceptable. Interrater reliability was excellent for global clinical assessments and decisions on radiological exclusion criteria although agreement for individual assessment items was more variable. Telemedicine systems were associated with increased use of tPA.</p>
<p><b>Conclusion:</b> Although there is limited reliable evidence, observational studies have indicated that telemedicine systems can be feasible, acceptable, and reliable in acute-stroke management. In addition, telemedicine consultations were associated with improved delivery of tPA.</p>
A model-based approach to recovering the structure of a plant from images
We present a method for recovering the structure of a plant directly from a
small set of widely-spaced images. Structure recovery is more complex than
shape estimation, but the resulting structure estimate is more closely related
to phenotype than is a 3D geometric model. The method we propose is applicable
to a wide variety of plants, but is demonstrated on wheat. Wheat is made up of
thin elements with few identifiable features, making it difficult to analyse
using standard feature matching techniques. Our method instead analyses the
structure of plants using only their silhouettes. We employ a generate-and-test
method, using a database of manually modelled leaves and a model for their
composition to synthesise plausible plant structures which are evaluated
against the images. The method is capable of efficiently recovering accurate
estimates of plant structure in a wide variety of imaging scenarios, with no
manual intervention
Identifying chemokines as therapeutic targets in renal disease: Lessons from antagonist studies and knockout mice
Chemokines, in concert with cytokines and adhesion molecules, play multiple roles in local and systemic immune responses. In the kidney, the temporal and spatial expression of chemokines correlates with local renal damage and accumulation of chemokine receptor-bearing leukocytes. Chemokines play important roles in leukocyte trafficking and blocking chemokines can effectively reduce renal leukocyte recruitment and subsequent renal damage. However, recent data indicate that blocking chemokine or chemokine receptor activity in renal disease may also exacerbate renal inflammation under certain conditions. An increasing amount of data indicates additional roles of chemokines in the regulation of innate and adaptive immune responses, which may adversively affect the outcome of interventional studies. This review summarizes available in vivo studies on the blockade of chemokines and chemokine receptors in kidney diseases, with a special focus on the therapeutic potential of anti-chemokine strategies, including potential side effects, in renal disease. Copyright (C) 2004 S. Karger AG, Basel
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