2,621 research outputs found

    Information technology-enabled explorative learning and competitive performance in industrial service SMEs: a configurational analysis

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    This is the author accepted manuscriptPurpose: As purveyors of knowledge-based and high value-added services to the manufacturing sector, industrial service small- and medium-sized enterprises (SMEs) must develop the information technology (IT) capabilities that, in combination with other non-IT capabilities, enable their capacity for organizational learning (OL) and for explorative learning in particular. In this context, this study aims to identify the different causal configurations that account for the nonlinear complex interplay of IT capabilities for exploration and strategic capabilities for explorative learning as they affect these firms’ competitive performance. Design/methodology/approach: Survey data obtained from 92 industrial service SMEs were analyzed with a configurational approach, using fuzzy set qualitative comparative analysis (fsQCA). Findings: As it allows for equifinality, the fsQCA analysis identified two sets of causal configurations that characterize the sampled firms’ explorative learning capability as it relates to competitive performance. In the first set, two configurations were equally associated with high innovation performance, whereas in the second set, four configurations were equally associated with high productivity. Originality/value: By viewing explorative learning as a dynamic capability that is enabled by the firm’s IT and strategic capabilities, the study contributes to OL theory by providing a more concrete or “operational” grounding, which allows for a greater practical applicability of this theory. By taking both the configurational and capability-based views of the OL-IT-performance causal framework, the authors provide an empirical basis for unraveling, explaining and understanding the complex non-linear relationships embedded within this framework

    Evolutionary optimization of service times in interactive voice response systems

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    A call center is a system used by companies to provide a number of services to customers, which may vary from providing simple information to gathering and dealing with complaints or more complex transactions. The design of this kind of system is an important task, since the trend is that companies and institutions choose call centers as the primary option for customer relationship management. This paper presents an evolutionary algorithm based on Dandelion encoding to obtain near-optimal service trees which represent the structure of the desired call center. We introduce several modifications to the original Dandelion encoding in order to adapt it to the specific problem of service tree design. Two search space size reduction procedures improve the performance of the algorithm. Systematic experiments have been tackled in order to show the performance of our approach: first, we tackle different synthetic instances, where we discuss and analyze several aspects of the proposed evolutionary algorithm, and second, we tackle a real application, the design of the call center of an Italian telecommunications company. In all the experiments carried out we compare our approach with a lower bound for the problem based on information theory, and also with the results of a Huffman algorithm we have used for reference

    A dandelion-encoded evolutionary algorithm for the delay-constrained capacitated minimum spanning tree problem

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    This paper proposes an evolutionary algorithm with Dandelion-encoding to tackle the Delay-Constrained Capacitated Minimum Spanning Tree (DC-CMST) problem. This problem has been recently proposed, and consists of finding several broadcast trees from a source node, jointly considering traffic and delay constraints in trees. A version of the problem in which the source node is also included in the optimization process is considered as well in the paper. The Dandelion code used in the proposed evolutionary algorithm has been recently proposed as an effective way of encoding trees in evolutionary algorithms. Good properties of locality has been reported on this encoding, which makes it very effective to solve problems in which the solutions can be expressed in form of trees. In the paper we describe the main characteristics of the algorithm, the implementation of the Dandelion-encoding to tackled the DC-CMST problem and a modification needed to include the source node in the optimization. In the experimental section of this article we compare the results obtained by our evolutionary with that of a recently proposed heuristic for the DC-CMST. the Least Cost (LC) algorithm. We show that our Dandelion-encoded evolutionary algorithm is able to obtain better results that the LC in all the instances tackled. (C) 2008 Elsevier B.V. All rights reserved

    Negative time delay for wave reflection from a one-dimensional semi-harmonic well

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    It is reported that the phase time of particles which are reflected by a one-dimensional semi-harmonic well includes a time delay term which is negative for definite intervals of the incoming energy. In this interval, the absolute value of the negative time delay becomes larger as the incident energy becomes smaller. The model is a rectangular well with zero potential energy at its right and a harmonic-like interaction at its left.Comment: 6 pages, 5 eps figures. Talk presented at the XXX Workshop on Geometric Methods in Physics, Bialowieza, Poland, 201

    Dose-dependent effects of dietary nitrate on the oxygen cost of moderate-intensity exercise: Acute vs. chronic supplementation

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordPURPOSE: To investigate whether chronic supplementation with a low or moderate dose of dietary nitrate (NO3(-)) reduces submaximal exercise oxygen uptake (V˙O2) and to assess whether or not this is dependent on acute NO3(-) administration prior to exercise. METHODS: Following baseline tests, 34 healthy subjects were allocated to receive 3 mmol NO3(-), 6 mmol NO3(-) or placebo. Two hours following the first ingestion, and after 7, 28 and 30 days of supplementation, subjects completed two moderate-intensity step exercise tests. On days 28 and 30, subjects in the NO3(-) groups completed the test 2 h post consumption of a NO3(-) dose (CHR + ACU) and a placebo dose (CHR). RESULTS: Plasma nitrite concentration ([NO2(-)]) was elevated in a dose-dependent manner at 2 h, 7 days and 28-30 days on the CHR + ACU visit. Compared to pre-treatment baseline, 6 mmol NO3(-) reduced the steady-state V˙O2 during moderate-intensity exercise by 3% at 2 h (P = 0.06), 7 days and at 28-30 days (both P < 0.05) on the CHR + ACU visit, but was unaffected by 3 mmol NO3(-) at all measurement points. On the CHR visit in the 6 mmol group, plasma [NO2(-)] had returned to pre-treatment baseline, but the steady-state V˙O2 remained reduced. CONCLUSION: Up to ∼4 weeks supplementation with 6 but not 3 mmol NO3(-) can reduce submaximal exercise V˙O2. A comparable reduction in submaximal exercise V˙O2 following chronic supplementation with 6 mmol NO3(-) can be achieved both with and without the acute ingestion of NO3(-) and associated elevation of plasma [NO2(-)].Financial support for this study was provided by the Gatorade Sports Science Institute, a division of PepsiCo, Inc. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc

    The Role of Spirituality Healing with Perceptions of the Medical Encounter among Latinos

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    Little is known about the relationship between spirituality healing and perceptions about the medical encounter among Latinos. To examine the association between spirituality healing and attitudes of self-reported perceptions about the medical encounter. A cross-sectional telephone survey. 3,728 Latinos aged ≥18 years residing in the United States from Wave 1 of the Pew Hispanic Center/Robert Wood Johnson Foundation Latino Health Survey. Dependent variables were ever prayed for healing (yes/no), ever asked others to pray for healing (yes/no), considered important spiritual healing (very vs. somewhat or not important), and ever consulted a ‘curandero’ (folk healer in Latin America) (yes/no). The primary independent variables were feelings about the last time seeing a Doctor (confused by information given, or frustrated by lack of information) and perception of quality of medical care (excellent, good, fair or poor) within the past 12 months. Six percent of individuals reported that they had ever consulted a curandero, 60% prayed for healing, 49% asked others to pray for healing, and 69% considered spiritual healing as very important. In multivariable analyses, feeling confused was associated with increased odds of consulting a curandero (OR = 1.58; 95% CI, 1.02–2.45), praying for healing (OR = 1.30; 95% CI, 1.03–1.64), asking others to pray for healing (OR = 1.29; 95% CI, 1.03–1.62), and considering spiritual healing as very important (OR = 1.30; 95% CI, 1.01–1.66). Feeling frustrated by a lack of information was associated with asking others to pray for healing (OR = 1.29; 95% CI, 1.04–1.60). A better perception of quality of medical care was associated with lower odds of consulting a curandero (OR = 0.83; 95% CI, 0.70–0.98). Feelings about the medical encounter were associated with spirituality healing, praying for healing, and asking others to pray for healing. Feeling confused and perception of poor quality of medical care were associated with consulting a curandero

    Effect of salt substitution on community-wide blood pressure and hypertension incidence

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    Replacement of regular salt with potassium-enriched substitutes reduces blood pressure in controlled situations, mainly among people with hypertension. We report on a population-wide implementation of this strategy in a stepped-wedge cluster randomized trial (NCT01960972). The regular salt in enrolled households was retrieved and replaced, free of charge, with a combination of 75% NaCl and 25% KCl. A total of 2,376 participants were enrolled in 6 villages in Tumbes, Peru. The fully adjusted intention-to-treat analysis showed an average reduction of 1.29 mm Hg (95% confidence interval (95% CI) (−2.17, −0.41)) in systolic and 0.76 mm Hg (95% CI (−1.39, −0.13)) in diastolic blood pressure. Among participants without hypertension at baseline, in the time- and cluster-adjusted model, the use of the salt substitute was associated with a 51% (95% CI (29%, 66%)) reduced risk of developing hypertension compared with the control group. In 24-h urine samples, there was no evidence of differences in sodium levels (mean difference 0.01; 95% CI (0.25, −0.23)), but potassium levels were higher at the end of the study than at baseline (mean difference 0.63; 95% CI (0.78, 0.47)). Our results support a case for implementing a pragmatic, population-wide, salt-substitution strategy for reducing blood pressure and hypertension incidence

    Uncertainties in projecting climate-change impacts in marine ecosystems

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    Projections of the impacts of climate change on marine ecosystems are a key prerequisite for the planning of adaptation strategies, yet theyare inevitablyassociated withuncertainty.Identifying,quantifying,andcommunicatingthisuncertaintyis keytobothevaluatingtherisk associated with a projection and building condence in its robustness. Wereview howuncertainties in such projections are handled in marine science. We employan approach developedin climatemodelling by breaking uncertainty down into(i) structural (model) uncertainty,(ii) initialization and internalvariabilityuncertainty,(iii)parametricuncertainty,and(iv)scenariouncertainty.Foreachuncertaintytype,wethenexaminethecurrent state-of-the-art in assessing and quantifying its relative importance. We consider whether the marine scientic community has addressed these types of uncertainty sufciently and highlight the opportunities and challenges associated with doing a better job. We nd that even within a relatively small eld such as marine science, there are substantial differences between subdisciplines in the degree of attention given to each type of uncertainty. We nd that initialization uncertainty is rarely treated explicitly and reducing this type of uncertainty may deliver gainsontheseasonal-to-decadaltime-scale.Weconcludethatallpartsofmarinesciencecouldbenetfromagreaterexchangeofideas,particularly concerningsuchauniversalproblemsuchasthetreatmentofuncertainty.Finally,marinescienceshouldstrivetoreachthepointwherescenario uncertainty is the dominant uncertainty in our projections

    Mechanical Systems with Symmetry, Variational Principles, and Integration Algorithms

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    This paper studies variational principles for mechanical systems with symmetry and their applications to integration algorithms. We recall some general features of how to reduce variational principles in the presence of a symmetry group along with general features of integration algorithms for mechanical systems. Then we describe some integration algorithms based directly on variational principles using a discretization technique of Veselov. The general idea for these variational integrators is to directly discretize Hamilton’s principle rather than the equations of motion in a way that preserves the original systems invariants, notably the symplectic form and, via a discrete version of Noether’s theorem, the momentum map. The resulting mechanical integrators are second-order accurate, implicit, symplectic-momentum algorithms. We apply these integrators to the rigid body and the double spherical pendulum to show that the techniques are competitive with existing integrators

    The United States, PMSCs and the state monopoly on violence: Leading the way towards norm change

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Sage.The proliferation of private military and security companies (PMSCs) in Iraq and Afghanistan has raised many questions regarding the use of armed force by private contractors. This article addresses the question of whether the increased acceptance of PMSCs indicates a transformation of the international norm regarding the state monopoly on the legitimate use of armed force. Drawing on theoretical approaches to the analysis of norm change, the article employs four measures to investigate possible changes in the strength and meaning of this norm: modifications in state behaviour, state responses to norm violation, the promulgation of varying interpretations of the norm in national and international laws and regulations, and changes in norm discourse. Based on an analysis of empirical evidence from the United States of America and its allies, the article concludes that these measures suggest that the USA is leading the way towards a transformation of the international norm of the state monopoly on violence, involving a revised meaning. Although this understanding has not yet been formally implemented in international law, it has allowed a growing number of countries to tolerate, accept or legalize the use of armed force by PMSCs in the international arena.The Alexander von Humboldt Foundation and the Peace Research Institute Frankfurt
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