10,651 research outputs found

    Parental cigarette smoking and childhood risks of hepatoblastoma: OSCC data

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    Historically health care data and especially health care cost data were not collected by disease. This is due on one side to a lack of readily available information on the diagnosis that led to the health care given and on the other side to the diversity of actors and organizations taking charge of patients. This results in a major difficulty of linking together incompatible and separate data. A few countries have tried to desagregate their global health cost data in a top-down approach. The limits of such undertakings appeared however quickly, not the least because of the difficulties in allocating the expenditures by sector and disease. Other approaches, probably more fecund in the long run, such as the one used by the SEER-Medicare database in the U.S. favour the linkage of individual patient clinical and cost data in a bottom-up approach. However one should not ignore the potential bias problems raised by the use of even large databases such as this one. A major advantage of clinical trials for costing purposes is that they include homogeneous groups of patients randomly allocated to several treatments for comparative purposes. They are therefore potentially better adapted for comparing new treatments with standard reference care

    Modern changes of the climate and glaciers in China's monsoonal temperate-glacier region

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    通过对中国季风温冰川区的气候实测资料、冰芯记录、树木年轮指数和冰川进退记载等多种指标的综合分析,较详细地研究了400年以来本区气候与冰川变化。自17~19世纪小冰期的两个寒冷阶段以后,中国季风温冰川分布区气温普遍波动上升,与全球变暖的大背景一致, 大部分冰川正在后退,但降水量变化则比较复杂,达索普冰芯记录證明,本区西部的喜马拉雅山地区降水量表现为下降的趋势,与气温变化相反,而东部的横断山等地的降水则表现为上升的趋势,与气温变化同步,这主要是不同来源大气环流影响的结果。研究区主要盛行来源于印度洋的西南季风,此外,其东部还受来源于西太平洋东南季风的影响,西部受西风环流南支的影响,造成中国季风温冰川区东西部不均匀的降水分布和变化趋势。小冰期以后,我国的季风温冰川对气候变暖反应敏感,绝大部分冰川持续后退。20世纪80年代以来,后退速度加剧,但后退幅度和规模因地而异。Climatic data, ice core records, the tree ring index and recorded glacier variations have been used to reconstruct a history of climatic and glacial changes in the monsoonal temperate-glacier region of southwestern China during the last 400 years. All the results indicate that the temperature in the region increased in a fluctuating manner during the 20th century, after the two cold stages of the Little Ice Age during the 17th-19th centuries, with a corresponding retreat of most of the glaciers against a background of global warming. However, the amount, trend and amplitude of variation of precipitation have differed in different parts of the region. The climatic records in the Dasuopu ice core, from the Himalaya area in the western part of the region, show a decreasing trend of precipitation, the converse of the trend of temperature. In the Hengduan Mountains and other areas of the eastern part of the region, however, a rising trend of rainfall has accompanied increasing temperatures, as a result of the variable atmosphere circulations from different sources. The data indicate that the southwestern monsoon, which is the principal controlling factor in the Chinese monsoonal temperate-glacier region, can be classified into two parts. One is the Indian monsoon from the Arabian Sea, passing across the Indian Peninsula. This transports the vapour for precipitation in the Himalaya area, the western part of the monsoonal temperate-glacier region. The other part is the Bengal monsoon from the Bay of Bengal, passing over Bangladesh and Burma. This is the major source of precipitation in the Hengduan Mountains and other areas of the eastern part of the region. In addition, the eastern part is influenced by the southeast monsoon from the western Pacific, whilst the western part is affected by the southern branch of the westerly circulation in winter. This complex atmospheric situation results in different patterns of precipitation in the western and eastern zones.link_to_subscribed_fulltextpublished_or_final_versio

    Quantum integrable system with two color components in two dimensions

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    The Davey-Stewartson 1(DS1) system[9] is an integrable model in two dimensions. A quantum DS1 system with 2 colour-components in two dimensions has been formulated. This two-dimensional problem has been reduced to two one-dimensional many-body problems with 2 colour-components. The solutions of the two-dimensional problem under consideration has been constructed from the resulting problems in one dimensions. For latters with the δ\delta -function interactions and being solved by the Bethe ansatz, we introduce symmetrical and antisymmetrical Young operators of the permutation group and obtain the exact solutions for the quantum DS1 system. The application of the solusions is discussed.Comment: 14 pages, LaTeX fil

    Structure of a model TiO2 photocatalytic interface

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    The interaction of water with TiO2 is crucial to many of its practical applications, including photocatalytic water splitting. Following the first demonstration of this phenomenon 40 years ago there have been numerous studies of the rutile single-crystal TiO2(110) interface with water. This has provided an atomic-level understanding of the water-TiO2 interaction. However, nearly all of the previous studies of water/TiO2 interfaces involve water in the vapour phase. Here, we explore the interfacial structure between liquid water and a rutile TiO2(110) surface pre-characterized at the atomic level. Scanning tunnelling microscopy and surface X-ray diffraction are used to determine the structure, which is comprised of an ordered array of hydroxyl molecules with molecular water in the second layer. Static and dynamic density functional theory calculations suggest that a possible mechanism for formation of the hydroxyl overlayer involves the mixed adsorption of O2 and H2O on a partially defected surface. The quantitative structural properties derived here provide a basis with which to explore the atomistic properties and hence mechanisms involved in TiO2 photocatalysis

    Critical Nature of Non-Fermi Liquid in Spin 3/2 Multipolar Kondo Model

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    A multipolar Kondo model of an impurity spin S_I=3/2 interacting with conduction electrons with spin s_c=3/2 is investigated using boundary conformal field theory. A two-channel Kondo (2CK) -like non-Fermi liquid (NFL) under the particle-hole symmetry is derived explicitly using a ``superspin absorption'' in the sector of a hidden symmetry, SO(5). We discuss the difference between the usual spin-1/2 2CK NFL fixed point and the present one. In particular, we find that, unlike the usual 2CK model, the low temperature impurity specific heat is proportional to temperature.Comment: 4 pages, 2 figure

    On the kinks and dynamical phase transitions of alpha-helix protein chains

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    Heuristic insights into a physical picture of Davydov's solitonic model of the one-dimensional protein chain are presented supporting the idea of a non-equilibrium competition between the Davydov phase and a complementary, dynamical- `ferroelectric' phase along the chainComment: small latex file with possible glue problems, just go on !, no figures, small corrections with respect to the published text, follow-up work to cond-mat/9304034 [PRE 47 (June 1993) R3818

    Monitoring synaptic transmission in primary neuronal cultures using local extracellular stimulation

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    Various techniques have been applied for the functional analysis of synaptic transmission in Cultured neurons. Here, we describe a method of studying synaptic transmission in neurons cultured at high-density from different brain regions such as the cortex, striatum and spinal cord. We use postsynaptic whole-cell recordings to monitor synaptic Currents triggered by presynaptic action potentials that are induced by brief stimulations with a nearby extracellular bipolar electrode. Pharmacologically isolated excitatory or inhibitory postsynaptic currents can be reliably induced, with amplitudes, synaptic charge transfers, and short-term plasticity properties that are reproducible from culture to culture. We show that the size and kinetics of pharmacologically isolated inhibitory postsynaptic Currents triggered by single action potentials or stimulus trains depend on the Ca2+ concentration, temperature and stimulation frequency. This method can be applied to study synaptic transmission in wildtype neurons infected with lentiviruses encoding various components of presynaptic release machinery, or in neurons from genetically modified mice, for example neurons carrying floxed genes in which gene expression can be acutely ablated by expression of Cre recombinase. The preparation described in this paper should be useful for analysis of synaptic transmission in inter-neuronal synapses formed by different types of neurons. (c) 2006 Elsevier B.V. All rights reserved

    Particle production and equilibrium properties within a new hadron transport approach for heavy-ion collisions

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    The microscopic description of heavy-ion reactions at low beam energies is achieved within hadronic transport approaches. In this article a new approach SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) is introduced and applied to study the production of non-strange particles in heavy-ion reactions at Ekin=0.42AE_{\rm kin}=0.4-2A GeV. First, the model is described including details about the collision criterion, the initial conditions and the resonance formation and decays. To validate the approach, equilibrium properties such as detailed balance are presented and the results are compared to experimental data for elementary cross sections. Finally results for pion and proton production in C+C and Au+Au collisions is confronted with HADES and FOPI data. Predictions for particle production in π+A\pi+A collisions are made.Comment: 30 pages, 30 figures, replaced with published version; only minor change
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