6,104 research outputs found
Low-temperature structural transition in FeCr_2S_4
Transmission electron microscopy studies of [110] and [111] oriented
FeCr_2S_4 single crystals at different temperatures reveal a structural
transition at low temperatures indicating a cubic-to-triclinic symmetry
reduction within crystallographic domains. The overall crystal symmetry was
found to be reduced from Fd3m to F-43m. The triclinic distortions were
suggested to result from the combined actions of tetragonal distortions due to
the Jahn-Teller active Fe^2+ ions and trigonal distortions due to a
displacement of the Cr^3+ ions in the direction.Comment: 4 pages, 8 figure
The use of a quantitative structure-activity relationship (QSAR) model to predict GABA-A receptor binding of newly emerging benzodiazepines
The illicit market for new psychoactive substances is forever expanding. Benzodiazepines and their derivatives are one of a number of groups of these substances and thus far their number has grown year upon year. For both forensic and clinical purposes it is important to be able to rapidly understand these emerging substances. However as a consequence of the illicit nature of these compounds, there is a deficiency in the pharmacological data available for these ‘new’ benzodiazepines. In order to further understand the pharmacology of ‘new’ benzodiazepines we utilised a quantitative structure-activity relationship (QSAR) approach. A set of 69 benzodiazepine-based compounds was analysed to develop a QSAR training set with respect to published binding values to GABAA receptors. The QSAR model returned an R2 value of 0.90. The most influential factors were found to be the positioning of two H-bond acceptors, two aromatic rings and a hydrophobic group. A test set of nine random compounds was then selected for internal validation to determine the predictive ability of the model and gave an R2 value of 0.86 when comparing the binding values with their experimental data. The QSAR model was then used to predict the binding for 22 benzodiazepines that are classed as new psychoactive substances. This model will allow rapid prediction of the binding activity of emerging benzodiazepines in a rapid and economic way, compared with lengthy and expensive in vitro/in vivo analysis. This will enable forensic chemists and toxicologists to better understand both recently developed compounds and prediction of substances likely to emerge in the future
Composite vertices that lead to soft form factors
The momentum-space cut-off parameter of hadronic vertex functions
is studied in this paper. We use a composite model where we can measure the
contributions of intermediate particle propagations to . We show that
in many cases a composite vertex function has a much smaller cut-off than its
constituent vertices, particularly when light constituents such as pions are
present in the intermediate state. This suggests that composite
meson-baryon-baryon vertex functions are rather soft, i.e., they have \Lambda
considerably less than 1 GeV. We discuss the origin of this softening of form
factors as well as the implications of our findings on the modeling of nuclear
reactions.Comment: REVTex, 19 pages, 5 figs(to be provided on request
Determinants of adolescent fertility in Ethiopia
Background: Worldwide, adolescents suffer from a disproportionate share of reproductive health problem. Throughout the world, over 14 million adolescents aged 15-19 years give birth annually. The purpose of this study was to assess the level and identify proximate and other determinants of adolescent fertility in Ethiopia.Methods: Raw data collected from all part of the country using stratified cluster sampling method by the Ethiopian Demographic Health Survey 2005 (EDHS-2005) was used. After the data for adolescents aged from 15 to 19 years were extracted from the large data set, Multivariate logistic regression model was applied to identify sociodemographic and economic determinants whereas Bongaarts model was used to determine proximate determinants fertility.Results: Of the 3,266 adolescent women, 443 (13.6%) had given birth at least once prior to the survey and 133 (4.1%) were pregnant. Of the 443 adolescents who had at least given birth, the majority (72.7%) had one child while about a quarter (23.2%) had 2 live births and the rest 1.0% gave four live births with a mean number of child ever born of 1.33±0.6. The major factors associated with adolescent fertility were age, educational status, place of residence, employment, marriage, contraceptive use and postpartum infecundability. The odds for increased adolescent fertility was significantly higher in early adolescents (AOR=7.6; 95% CI=6.0 to 9.9), had lower education (AOR=6.7; 95%CI=4.1 to10.9), among rural teens (AOR=3.6; 95%CI=1.9 to 6.9) and currently not working (AOR=1.7; 95%CI= 1.3 to 2.2) than their counterparts. The observed fertility rate of 0.52 children per woman obtained from Bongaarts model of fertility indicated about 1.98 births per woman were averted due to non-marriage, delayed marriage, contraceptive use and postpartum infecundability.Conclusion: Since adolescent fertility is felt to be a problem, concerted efforts are needed to empower adolescents to fight early marriage, promote education and encourage the utilization of family planning targeting the rural teenagers. [Ethiop. J. Health Dev. 2010;24(1):30-38
General method for extracting the quantum efficiency of dispersive qubit readout in circuit QED
We present and demonstrate a general three-step method for extracting the
quantum efficiency of dispersive qubit readout in circuit QED. We use active
depletion of post-measurement photons and optimal integration weight functions
on two quadratures to maximize the signal-to-noise ratio of the
non-steady-state homodyne measurement. We derive analytically and demonstrate
experimentally that the method robustly extracts the quantum efficiency for
arbitrary readout conditions in the linear regime. We use the proven method to
optimally bias a Josephson traveling-wave parametric amplifier and to quantify
different noise contributions in the readout amplification chain.Comment: 10 pages, 6 figure
Determination of the Optimal Sterilization Regime of Canned Quail Meat with Hydrocoloids Application
The use of hydrocolloids in the modern meat industry is the one of prospective directions for improving functional and technological characteristics of meat and meat products, including poultry at long storage terms. A series of concrete requirements to functional-technological, physical-chemical and organoleptic parameters is offered for canned poultry in correspondence with minimal specifications for the quality of products of an animal origin.There is presented the study of the optimization of the process of meat products sterilization using meat of chicken-broilers, quails and hydrocolloids depending on physical-chemical and organoleptic properties. The parameters of quail meat use in recipes of canned poultry meat with hydrocolloids were considered. The influence of the sterilization process on characteristics of chicken-broiler and quail meat was established.There was revealed the essential difference in the influence on functional and technological parameters of canned quail meat using hydrocolloid mixtures comparing with canned chicken-broiler meat, manifested in changes of MKC (moisture keeping capacity), plasticity and salt content in jelly. At changing sterilization regimes, there takes place the change of physical and chemical characteristics of gels that correlates with organoleptic characteristics. For providing high quality parameters of canned poultry meat and industrial sterility, sterilization regimes for canned chicken-broiler meat must be realized for containers with the volume 500 with sterilization time no more than 90 minutes. For canned quail meat the sterilization process duration must be increased to 120 min at the temperature 115 ° С
FlaME: Flash Molecular Editor - a 2D structure input tool for the web
<p>Abstract</p> <p>Background</p> <p>So far, there have been no Flash-based web tools available for chemical structure input. The authors herein present a feasibility study, aiming at the development of a compact and easy-to-use 2D structure editor, using Adobe's Flash technology and its programming language, ActionScript. As a reference model application from the Java world, we selected the Java Molecular Editor (JME). In this feasibility study, we made an attempt to realize a subset of JME's functionality in the Flash Molecular Editor (FlaME) utility. These basic capabilities are: structure input, editing and depiction of single molecules, data import and export in molfile format.</p> <p>Implementation</p> <p>The result of molecular diagram sketching in FlaME is accessible in V2000 molfile format. By integrating the molecular editor into a web page, its communication with the HTML elements on this page is established using the two JavaScript functions, <it>getMol() </it>and <it>setMol()</it>. In addition, structures can be copied to the <it>system clipboard</it>.</p> <p>Conclusion</p> <p>A first attempt was made to create a compact single-file application for 2D molecular structure input/editing on the web, based on Flash technology. With the application examples presented in this article, it could be demonstrated that the Flash methods are principally well-suited to provide the requisite communication between the Flash object (application) and the HTML elements on a web page, using JavaScript functions.</p
An efficient RAN slicing strategy for a heterogeneous network with eMBB and V2X services
Emerging 5G wireless technology will support services and use cases with vastly heterogeneous requirements. Network slicing, which allows composing multiple dedicated logical networks with specific functionality running on top of a common infrastructure, is introduced as a solution to cope with this heterogeneity. At the radio access network (RAN), the use of network slicing involves the assignment of radio resources to each slice in accordance with its expected requirements and functionalities. Therefore, RAN slicing will provide the required design flexibility and will be necessary for any network slicing solution. This paper investigates the RAN slicing problem for providing two generic services of 5G, namely enhanced mobile broadband (eMBB) and vehicle-to-everything (V2X). In this respect, we propose an efficient RAN slicing scheme based on an off-line reinforcement learning followed by a low-complexity heuristic algorithm, which allocates radio resources to different slices with the target of maximizing the resource utilization while ensuring the availability of resources to fulfill the requirements of the traffic of each RAN slice. A simulation-based analysis is presented to assess the performance of the proposed solution. The simulation results have shown that the proposed algorithm improves the network performance in terms of resource utilization, the latency of V2X services, achievable data rate, and outage probability.Peer ReviewedPostprint (published version
The Effect of Website Improvements of the Amman Stock Exchange on Its Financial Performance
The big revolution in the field of information technology and information network (Internet) a significant impact on the performance of various institutions activities . So This study aimed to identify the impact of the evolution of the website of the Amman Stock Exchange on its financial performance study sample consisted of (50) individual included managers, department heads, and staff., Where results showed the presence of the impact the development of the website of the Amman Stock Exchange on its financial performance. Keywords: financial performance, website, Amman stock exchange (ASE).
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