15,389 research outputs found

    String Memory Effect

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    In systems with local gauge symmetries, the memory effect corresponds to traces inscribed on a suitable probe when a pure gauge configuration at infinite past dynamically evolves to another pure gauge configuration at infinite future. In this work, we study the memory effect of 2-form gauge fields which is probed by strings. We discuss the "string memory effect" for closed and open strings at classical and quantum levels. The closed string memory is encoded in the internal excited modes of the string, and in the open string case, it is encoded in the relative position of the two endpoints and the noncommutativity parameter associated with the D-brane where the open string endpoints are attached. We also discuss 2-form memory with D-brane probes using boundary state formulation and, the relation between string memory and 2-form soft charges analyzed in [1]

    The Economics of Conflicts of Interest in Financial Institutions

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    A conflict of interest exists when a party to a transaction could potentially make a gain from taking actions that are detrimental to the other party in the transaction. This paper examines the economics of conflicts of interest in financial institutions and reviews the growing empirical literature (mostly focused on analysts) on the economic implications of these conflicts. Economic analysis shows that, although conflicts of interest are omnipresent when contracting is costly and parties are imperfectly informed, there are important factors that mitigate their impact and, strikingly, it is possible for customers of financial institutions to benefit from the existence of such conflicts. The empirical literature reaches conclusions that differ across types of conflicts of interest, but overall these conclusions are more ambivalent and certainly more benign than the conclusions drawn by journalists and politicians from mostly anecdotal evidence. Though much has been made of conflicts of interest arising from investment banking activities, there is no consensus in the empirical literature supporting the view that conflicts resulting from these activities had a systematic adverse impact on customers of financial institutions.

    Differential Distributed Space-Time Coding with Imperfect Synchronization

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    Differential distributed space-time coding (D-DSTC) has been considered to improve both diversity and data-rate in cooperative communications in the absence of channel information. However, conventionally, it is assumed that relays are perfectly synchronized in the symbol level. In practice, this assumption is easily violated due to the distributed nature of the relay networks. This paper proposes a new differential encoding and decoding process for D-DSTC systems with two relays. The proposed method is robust against synchronization errors and does not require any channel information at the destination. Moreover, the maximum possible diversity and symbol-by-symbol decoding are attained. Simulation results are provided to show the performance of the proposed method for various synchronization errors and the fact that our algorithm is not sensitive to synchronization error.Comment: to appear in IEEE Globecom, 201

    Soil salinity-sodicity and land use suitability in the Fordwah Eastern Sadiqia (South) irrigated area

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    Soil salinity / Sodic soils / Soil classification / Soil surveys / Soil analysis / Groundwater development / Water table / Water quality / Land use / Irrigation canals / Farmer participation / Surface drainage / Subsurface drainage / Soil reclamation / Waterlogging / Pakistan / Fordwah Eastern Sadiqia / Bahawalnagar District

    Medical errors : Healthcare professionals’ perspective at a tertiary hospital in Kuwait

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    Medical errors are of economic importance and can contribute to serious adverse events for patients. Medical errors refer to preventable events resulting from healthcare interactions, whether these events harm the patient or not. In Kuwait, there is a paucity literature detailing the causes, forms, and risks of medical errors in their state-funded healthcare facilities. This study aimed to explore medical errors, their causes and preventive strategies in a Kuwait tertiary hospital based on the perceptions and experience of a cross-section of healthcare professionals using a questionnaire with 27 open (n = 10) and closed (n = 17) questions. The recruited healthcare professionals in this study included pharmacists, nurses, physicians, dentists, radiographers, hospital administrators, surgeons, nutritionists, and physiotherapists. The collected data were analysed quantitatively using descriptive statistics. A total of 203 participants filled and completed the survey questionnaire. The frequency of medical errors in Kuwait was found to be high at 60.3% ranging from incidences of prolonged hospital stays (32.9%), adverse events and life-threatening complications (32.3%), and fatalities (20.9%). The common medical errors result from incomplete instructions, incorrect dosage, and incorrect route of administration, diagnosis errors, and labelling errors. The perceived causes of these medical errors include high workload, lack of support systems, stress, medical negligence, inadequate training, miscommunication, poor collaboration, and non-adherence to safety guidelines among the healthcare professionals.Peer reviewe
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