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Search Results: 1 - 10 of 465298 matches for " Roger A Band "
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Hypothermia and cardiac arrest: the promise of intra-arrest cooling
Roger A Band, Benjamin S Abella
Critical Care , 2008, DOI: 10.1186/cc6845
Abstract: In the previous issue of Critical Care, Bruel and colleagues report findings from a small, prospective, observational study in which they investigate the feasibility, efficacy and safety of intra-arrest therapeutic hypothermia (TH) for victims of out-of-hospital cardiac arrest (OHCA) [1]. From an initial pool of 412 cardiac arrest victims, the study enrolled 33 patients with a variety of presenting rhythms. This represents the first study of its kind to investigate the feasibility of intra-arrest cooling in the clinical setting, an approach that has shown significant promise in animal models of cardiac arrest and brain injury [2-4].Sudden cardiac arrest, defined as the abrupt loss of mechanical cardiac activity and concomitant global loss of blood flow, is a leading cause of death in the United States and Europe. Approximately 200,000 people suffer OHCA in the United States each year, and over 90% will succumb during resuscitation efforts or during subsequent hospitalization [5,6]. Survival to hospital discharge depends on a number of factors, including prompt delivery of cardiopulmonary resuscitation and defibrillation when indicated, the initial cardiac rhythm of arrest, and the quality of post-resuscitation care including provision of TH.Despite the significant effort that has been invested in this field, few therapeutic or pharmacologic interventions have yielded meaningful increases in overall survival from OHCA over the past 20 years [6,7]. The relatively new and evolving treatment modality of TH, however, has been associated with markedly decreased mortality and neurologic injury among patients who initially survive OHCA [8,9].TH reduces both the cerebral metabolic rate and oxygen demand, and it is thought to attenuate reperfusion injury, global inflammation and endothelial dysfunction – all consequences of cerebral and other organ ischemia [10,11]. Through such mechanisms, TH is thought to improve clinical parameters and outcomes. Two landmark multicenter ra
Collisional shifts in optical-lattice atom clocks
Y. B. Band,A. Vardi
Physics , 2006, DOI: 10.1103/PhysRevA.74.033807
Abstract: We theoretically study the effects of elastic collisions on the determination of frequency standards via Ramsey fringe spectroscopy in optical-lattice atom clocks. Interparticle interactions of bosonic atoms in multiply-occupied lattice sites can cause a linear frequency shift, as well as generate asymmetric Ramsey fringe patterns and reduce fringe visibility due to interparticle entanglement. We propose a method of reducing these collisional effects in an optical lattice by introducing a phase difference of $\pi$ between the Ramsey driving fields in adjacent sites. This configuration suppresses site to site hopping due to interference of two tunneling pathways, without degrading fringe visibility. Consequently, the probability of double occupancy is reduced, leading to cancellation of collisional shifts.
Mitigating Biodiversity Concerns in Eucalyptus Plantations Located in South China  [PDF]
Roger A. Williams
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.36001

China’s growing economy and changes in policies that encourage afforestation, particularly in the industrial sector, have led vast areas in south China to be planted with eucalyptus. These large areas of eucalyptus plantings have elicited environmental concerns for two primary reasons. First there is a concern related to the water demand of eucalyptus, in which it is feared these large areas of eucalyptus will deplete aquifers and create shortages in water supplies. The second concern is in regard to the reduction in biodiversity across large landscapes, leading to further ecological demises. This paper proposes two ideas to possibly mitigate some of the biodiversity concerns. The first is the interplanting of alder-leaf birch (Betula alnoides), a native but dwindling species in south China, to enhance biodiversity and encourage it’s reestablishment across the landscape. The second is to encourage retention harvests of alder-leaf birch planted within eucalyptus plantations to enhance not only biological diversity but also structural diversity across the landscape. Alder-leaf birch has demonstrated great potential in producing high quality timber and wood for use in furniture manufacturing.

Improved Win-Win Quiescent Point Algorithm: A Recommender System Approach
A.A. Niknafs,H. Baghche Band
Journal of Applied Sciences , 2010,
Abstract: The aim of this study is introducing an online intelligent method for bidding negotiations in e-marketing. The growth and popularity of internet, increases using of modern techniques to help costumers and sellers in choosing best product and achieve higher benefit. Recommender systems as useful mean have memorable role in permanency customer loyalty. In traditional trade, customer and seller negotiate face to face. But now in online trade, it has changed to negotiation through internet and recommender systems. As a result, paying attention to preferences of both customer and seller in online structure is needed. In this study, we propose a method for making a recommender system for both seller and customer such that the satisfaction level of both be more than a threshold margin. First the needs and preferences of seller and customer are determined and then through the proposed algorithm successive suggestions are made until achieving a point that both sides of the business feel satisfaction.
On the conversion efficiency of ultracold fermionic atoms to bosonic molecules via Feshbach resonances
E. Pazy,A. Vardi,Y. B. Band
Physics , 2004, DOI: 10.1103/PhysRevLett.93.120409
Abstract: We explain why the experimental efficiency observed in the conversion of ultracold Fermi gases of $^{40}$K and $^{6}$Li atoms into diatomic Bose gases is limited to 0.5 when the Feshbach resonance sweep rate is sufficiently slow to pass adiabatically through the Landau Zener transition but faster than ``the collision rate'' in the gas, and increases beyond 0.5 when it is slower. The 0.5 efficiency limit is due to the preparation of a statistical mixture of two spin-states, required to enable s-wave scattering. By constructing the many-body state of the system we show that this preparation yields a mixture of even and odd parity pair-states, where only even parity can produce molecules. The odd parity spin-symmetric states must decorrelate before the constituent atoms can further Feshbach scatter thereby increasing the conversion efficiency; ``the collision rate'' is the pair decorrelation rate.
Control of Ultra-cold Inelastic Collisions by Feshbash Resonances and Quasi-One-Dimensional Confinement
V. A. Yurovsky,Y. B. Band
Physics , 2006, DOI: 10.1103/PhysRevA.75.012717
Abstract: Cold inelastic collisions of atoms or molecules are analyzed using very general arguments. In free space, the deactivation rate can be enhanced or suppressed together with the scattering length of the corresponding elastic collision via a Feshbach resonance, and by interference of deactivation of the closed and open channels. In reduced dimensional geometries, the deactivation rate decreases with decreasing collision energy and does not increase with resonant elastic scattering length. This has broad implications; e.g., stabilization of molecules in a strongly confining two-dimensional optical lattice, since collisional decay of the highly vibrationally excited states due to inelastic collisions is suppressed. The relation of our results with those based on the Lieb-Liniger model are addressed.
An Investigation of the Carbon Neutrality of Wood Bioenergy  [PDF]
Roger A. Sedjo, Xiaohui Tian
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.39114
Abstract: Wood biomass has been viewed as “carbon neutral”—its uses as energy have a zero carbon footprint. Some observers argue that the use of wood biofuels will result in a decrease of the forest stock and a net reduction of the carbon captured in the forest. Such assessments take a static, accounting view of forest systems and do not consider the effects of management in renewing the forest and increasing its extent or ability to sequester carbon. This paper addresses the carbon neutrality debate using a dynamic optimization forest management model to examine the effect on the existing and future forests of a changing demand for wood biomass. The results show that under market optimizing conditions, when future demand is anticipated to increase for significant periods, the response of managers will be to increase the intensity of forest production thereby offsetting much of the carbon released in bioenergy production.
Expanding public health professionals’ roles in promoting and supporting breastfeeding as optimal infant feeding: A pilot study with online tutorial implications  [PDF]
Amna Umer, Roger A. Edwards
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.32025

Background: Their knowledge of preventive health, coupled with their dynamic roles in the community, puts public health professionals in a key position to expand their roles in the health promotion and support of breastfeeding as optimal infant feeding. This online tutorial was created to increase public health professionals’ knowledge about breastfeeding and to assess their attitudes in supporting healthy behaviors related to infant feeding as a health promotion strategy. Method: The study utilized an online breastfeeding tutorial based on the US Breast-feeding Committee recommendations for minimum breastfeeding knowledge for health professionals. Pre- and post-tutorial questionnaires assessed breastfeeding knowledge, and an attitudinal survey evaluated attitudes of public health professionals after the tutorial. Exposing public health students to this information can facilitate the early shaping of their attitudes and understanding about the importance of breastfeeding. Results: Fifty-two Northeastern University MPH students and alumni (62% response rate) completed the study. There was an overall gain in participants’ fundamental knowledge regarding breastfeeding as assessed by pre- (77%) to post-tutorial (97%) correct responses (p = 0.00001). The post-tutorial attitudinal survey showed that 92% of participants were comfortable in answering questions about breastfeeding as part of their professional responsibilities. Conclusion: This pilot study highlights the important role that a short online tutorial can play in expanding public health professionals’ knowledge about breastfeeding. Greater use of online methods can enhance awareness of critical health behaviors, such as breastfeeding, that have not received adequate attention in public health curricula. This pilot study provides the foundation for a larger study. Integration of breastfeeding into public health professionals’ core training could support broader social change.

Modelling Open Channel Flows with Vegetation Using a Three-Dimensional Model  [PDF]
Guanghai Gao, Roger A. Falconer, Binliang Lin
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.32013
Abstract: The effects of vegetation on the flow structure are investigated in this paper. In previous studies of modelling vegetated flows, two-equation turbulence models, such as the model, were often used. However, this approach involves a level of uncertainty since the empirical coefficients in these two equations have not yet been satisfactorily obtained for such flow conditions. In addition to this, two extra partial differential equations needing which will result in an increase in the computational cost. The main purpose of the study was therefore to try and acquire accurate velocity profiles without the more advanced two-equation turbulence models. A three-dimensional model using a simple two layer mixing length model was therefore used. The governing hydrodynamic equations were refined to include the effects of drag force induced by vegetation on the flow structure. The model was applied to an experiment flume to study the flow field with vegetations, where experiment data are available. Distributions predicted by the model were compared with laboratory measured ones, with very good agreements being obtained. The results showed that the simple mixing length model could produce accurate complex velocity profile predictions requiring fewer coefficient data and less computation.
Numerical Modelling Sediment-Bacteria Interaction Processes in the Severn Estuary  [PDF]
Guanghai Gao, Roger A. Falconer, Binliang Lin
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.31003
Abstract: Faecal bacteria exist in both free-living and attached forms in estuarine waters. The deposition of sediments can take faecal bacteria out of the water column and to the bed. The sediments can subsequently be re-suspended to the water column, which can then lead to re-suspension of the faecal bacteria of the attached forms back to the water column. Therefore, the fate and transport of faecal bacteria is highly related to the governing sediment transport processes, particularly where these processes are significant, such as the Severn Estuary, UK. However, little attempt has been made to model such processes in terms of predicting the impact of the sediment fluxes on faecal bacteria levels. Details are given of the refinement of a numerical model of faecal bacteria transport, where the sediment transport processes are significant. After testing the sediment-bacteria interaction model favourably against known results in previous study, the model was applied to the Severn Estuary and Bristol Channel, UK, to investigate the impact of suspended sediment fluxes on the corresponding faecal bacteria transport processes. The model predictions have proved to be encouraging, with the results being compared to a traditional faecal bacteria modelling approach, where sediment bacteria interactions were not included. The new model provides improved predictions of faecal bacteria concentrations when sediment transport is included and for the Bristol Channel Severn Estuary it can be seen that the effects of the sediments on the bacterial levels in the water column can be significant.
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