This thesis investigates the influence of wheelset structural flexibility and track flexibility on the vehicle-track dynamic interaction, mainly in terms of wheel-rail forces up to 200 Hz, using simulations and measurements. The previous knowledge in this field is first reviewed and summarized, then two case studies are selected for investigation. The first case study involves a locomotive running on a tangent track section at a speed of 140 km/h, while the second one deals with a newly designed motor coach running at two adjacent and tangent track sections with different track components and at speeds up to 280 km/h. For the locomotive case study, the wheelset dynamic properties are first investigated through experimental modal analysis (EMA) for a frequency range of 0-500 Hz, assuming free boundary conditions. The EMA results showed relatively low wheelset eigenfrequencies. A three-dimensional finite element (FE) model, which also includes the wheelset gear-box, is then developed and validated against the measurements for frequencies up to 200 Hz with good agreement. The FE results displayed a significant influence of the wheels’ flexibility on the wheelset’s total structural flexibility. In order to assure proper representation of the track flexibility the vertical and lateral dynamic track properties at a sleeper are measured through a special vehicle at standstill, and measured track irregularities are used. In the numerical simulations, the wheelset structural flexibility is introduced using the calculated eigenmodes above while so-called moving track models are used to model the track flexibility. The simulated wheel-rail forces are then validated against measured ones obtained from corresponding on-track measurements. Results from the simulations highlight the importance of proper track flexibility modelling and track data and also show a significant influence of the wheelset structural flexibility on the lateral track forces. For the motor coach case study, the wheelset dynamic properties are determined through numerical modal analysis using a rather simple FE model and a number of eigenmodes are then introduced in the simulations. The vertical and lateral track dynamic properties at selected track sections are measured using the standstill technique but rolling stiffness measurements, where the vertical track flexibility in the frequency range 5-50 Hz is measured continuously along the track, are also included. The track flexibility is introduced through moving track models. Measured track irregularity and vertical track roughness are also considered. Basic numerical simulations, where the calculated track forces are compared to measured ones, are first performed and followed by a set of parametric studies. The results display a significant influence of the track flexibility on vertical wheel-rail forces for frequencies above 80 Hz, with higher forces for the stiffer track (but weaker rails). The effect of wheelset structural flexibility on the lateral force is also confirmed. The parametric studies highlight the importance of track flexibility modelling and show that modifications of the vertical track receptance, motivated by uncertainties in the pertinent measurements, can improve the simulated forces. / QC 20100701

How do public organizations manage crises? How do public organizations learnfrom crises? These seemingly basic questions still pose virtual puzzles for crisismanagement researchers. Yet, the interest of the academic and practitionerrealms in crisis management has grown in recent years. In this doctoral dissertationEdward Deverell sheds light on the problems regarding the lack ofknowledge on how public organizations manage and learn from crises, with anumber of critical knowledge gaps in contemporary crisis management as thestarting point.   In the last few decades the interest in crisis management as a scholarly fieldhas grown. This developing field is composed of an increasing number of looselyconnected social science scholars concerned with issues of extraordinary events,their repercussions and the way in which they are managed by authorities,organizations, policy makers and other key actors. However, there are severallacunae to be dealt with in the emerging field of crisis management research.This dissertation sets the spotlight on four of these limitations of the crisis managementliterature to date.   First, influential scholars within the field call for increased structuration andfeasible models to help us understand and explain various important factorsinfluencing the crisis management process. In this dissertation I try to bridgethis gap by developing theory on crisis response and learning. Crisis responsesignifies organized activities undertaken by a stakeholder when a community ofpeople – an organization, a town, or a nation – perceives an urgent threat to corevalues which must be dealt with under conditions of uncertainty. Crisis-inducedlearning refers to purposeful efforts, triggered by a crisis event and carried out bymembers of an organization working within a community of inquiry, that leadto new understanding and behavior on the basis of that understanding.   Second, organizations play a key role in crisis management. Surprisinglyenough, however, crisis management research have only occasionally built theoryon how organizations respond to crisis. So far, the literature tells us moreabout crises as events than on how these events are actually managed. One reasonis the focus within crisis management research on highly unusual, big catastrophicevents and industrial accidents. Therefore, this dissertation explorescrisis episodes that affect specific organizations rather than entire communitiesor national governments. In addition, the dissertation brings together debateson crisis management and crisis-induced learning from a public managementand organizational perspective.   Third, crisis management researchers have to date dealt mostly with acutecrisis response and issues of preparedness, while the issues of crisis aftermathsand crisis-induced learning are still relatively unknown. However, althoughthis study recognizes the importance of crisis planning and sense-making, thisshould not lead to a relative neglect of the issue of learning from crisis. Crisisinducedlearning is important as crises are rare events with huge repercussions.Thus crises are opportunities to draw lessons in order to improve future managementand crisis response, and to mitigate the risk of future crises.   Fourth, the relatively few studies that have dealt with crisis-induced learninghave focused on learning after the crisis (intercrisis learning), while theoryon learning during crisis (intracrisis learning) is not as developed. My interestin both inter- and intracrisis learning obligates me to study crisis response andcrisis learning in conjunction. This means studying how organizations respondto crises and how they learn during and from these episodes. By focusing onprocesses of crisis response and learning under pressure – rather than pre-crisisplanning, threat perception, risk management and preparedness – the dissertationlooks into how organizations and their members manage the challenge ofcrises and how they take on, make use of and implement lessons learned fromone crisis to the next.   The lacunae outlined above are theoretical points of departure for this dissertation’sinterest in the extent to which public organizations learn from crises.Accordingly, the overall objective of the dissertation is to increase understandingof crisis response and crisis learning in public organizations. In doing so, Iconduct an abductive study of how public organizations respond to crises andhow they learn during and after these events. The term ‘abductive’ refers toa research strategy which is characterized by continuous movement back andforth between theory and empirical data.   The first step of the research process was grounded in the empirical world.The empirical contribution is a careful process tracing and case reconstructionof six cases involving Swedish public sector organizations. In the methodologychapter (Chapter 3) I describe the basis of the empirically bounded case study approach and case reconstruction and process tracing method. Six case studiesof organizational crisis management and learning were selected for furtheranalysis. The case studies were based on a variety of sources including posthoc accident investigations, articles, organizational documents and 129 extensivesemi-structured interviews with key crisis managers. The process tracingand reconstruction efforts led to case narratives, which were then dissected byidentifying dilemmas and critical decision-making occasions that were studiedin more detail. The following cases are explored in the dissertation: TheSwedish energy utility Birka Energi’s management of two cable fires that causedlarge-scale blackouts in Stockholm in March 2001 and May 2002; The cityof Stockholm’s management of the 2001 blackout and the repeated incidentin 2002; The Swedish Defence Research Agency’s (FOI) management of hoaxanthrax letters in 2001; and three Swedish media organizations’ (the Swedishpublic service radio Sveriges Radio, the Swedish private TV station with publicservice tasks TV4, and the Swedish public service TV station Sveriges Television)management of news work and broadcasting challenges on 11 September 2001(and to some extent following the murder of the Swedish Foreign MinisterAnna Lindh in September 2003).   As the case selection reveals, all organizations under study are not puregovernment organizations. Rather three organizations (Birka Energi, SverigesRadio and Sveriges Television) are publically owned corporations, while one(TV4) is a privately owned media organization. Accordingly, this dissertationclaims that ownership is not the only measure of ‘publicness’. Media organizations,for instance, are of great importance for democratic societies. The term‘public organization’ is thus in this dissertation not used in the sense of equatingto government, but rather in reference to the degree of which political authorityand influence impacts on the organization.   The theory generating approach that this dissertation takes on impliesthat the case studies are ‘heuristic’ case studies. The dissertation aims to promotenew hypotheses for further research rather than to produce generalizedknowledge. To this end the case studies are further analyzed by specific theoreticalapproaches suggested by prior research. This second step of the researchprocess is dealt with in some detail in the literature review. The literature reviewin Chapter 2 aims to bring an injection of organizational studies into the fieldof crisis management research. The review presents relevant studies from thefields of crisis management studies, organization studies (with special attentiongiven to organizational learning theory) and public administration and management.The review puts forth a twofold argument: There is a need of increasedknowledge not only about crises and how they develop, but also about how theyare actually managed by public organizations. However, prior crisis managementresearch with bearing on public management organizations are mostly based on either political executive foreign policy decision making or on veryspecific high reliability organizations operating in the pre-crisis phase. Hence,organization studies and public management studies should play a greater partin crisis management research.   The review also provides an overview frame for the study by highlightingrelevant research. The chapter discusses the problems of defining, categorizingand operationalizing key concepts such as crisis, crisis management and organizationallearning.   In the third step of the research process, the case studies are further analyzedusing theoretical approaches aimed at proposing propositions on how publicsector organizations may respond to crises, and how they may learn from theircrisis experiences. These analyses have been carried out with an aim to producestand-alone articles aimed for publication in international scholarly journals.Thus this dissertation differs somewhat from the typical public administrationdissertation as it is comprised of an analysis of several articles, as opposed to amonograph. The journal articles are published or accepted for publication inthe Journal of Contingencies and Crisis Management, the Journal of HomelandSecurity and Emergency Management, Public Management Review, and RiskManagement. The articles are reprinted in four empirical chapters (Chapters4-7), which make up the core of the dissertation. Introductory and concludingchapters aimed at bringing the discussion together have then been added.I present the first empirical analysis in Chapter 4. It looks into how organizationalculture affects strategy and adaptability in crisis management. The keyresearch question is: What mechanisms affect organizations’ ability to restructurein order to cope with acute crisis management challenges? In the study I propose atypology of temporal organizational responses to crises in public perception. Thetypology is based on organizations’ abilities to change strategy and adapt theirmanagerial and operational levels to deal with crises. The empirical data used toconstruct the typology covers three organizational crisis responses: 1) The utilityBirka Energi’s response to a cable fire that caused a thirty-seven hour blackoutin Stockholm in 2001; 2) The TV station TV4’s response in terms of how toreorganize and broadcast during the 11 September 2001 terrorist attacks; 3)FOI, the Swedish National Defence Research Agency’s response to the anthraxletter scare of 2001 and 2002. The different organizational outcomes featuredby the typology reveal distinct aspects of organizational crisis management.According to the typology, the Fully Adapting Organization (TV4) managesto adapt both its strategy and its managerial and operational levels to deal withthe crisis. The Semi-Adapting Organization (FOI) changes its strategy but lacksthe capacity to change managerial and operational levels according to the newstrategy. The Non-Adapting Organization (Birka Energi) does not grasp theimportance of strategy change in the first place. Based on three inductive case studies, the study concludes that organizational culture plays an important rolein this process where the Semi-Adapting Organization and the Non-AdaptingOrganization were dominated by strong expert cultures which proved to be lessinclined to change. In contrast, the Fully Adapting organization had deliberatelyfostered an organizational culture in which flexibility – understood as thecapacity to readily adapt to changing demands – was a cornerstone.   The second empirical analysis is presented in Chapter 5. It deals with theissue of flexibility and rigidity in crisis response and crisis learning at two Swedishpublic organizations. The point of departure for the study is that the relationshipbetween crises, organizational crisis management response and learning hasto date been understudied. In an effort to broaden theoretical knowledge on therelation between crisis and learning, the study analyzes the crisis responses oftwo public organizations during a sequence of two failures. The empirical datais grounded in thorough process tracing and case reconstruction analyses ofhow the utility Birka Energi and the city of Stockholm managed two comprehensiveblackouts in March 2001 and in May 2002. The key research questionis: How does organizational rigidity and flexibility affect public organizations’ crisisresponse and crisis learning? A framework of rigidity versus flexibility in responseis utilized in the analysis. The findings are then discussed in relation to theirimplications for the nexus between crisis and learning. The study concludes byraising four propositions for further research.   The third empirical analysis is presented in Chapter 6. This study aims tocontribute to the debate on organizational learning from crisis by sheddinglight on the phenomenon of crises as learning triggers. In the study I pose thefollowing key research question: How can we analyze organizational learningduring and after crisis and what criteria should be part of the analysis? In an effortto unveil patterns of how organizational crisis-induced learning may appearand develop, I suggest a conceptual framework based on conceptual categoriesand answers to four fundamental questions: what lessons are learned (single- ordouble-loop)?; what is the focus of the lessons (prevention or response)?; whenare lessons learned (intra- or intercrisis)?; is learning carried out or blocked fromimplementation (distilled or implemented)? In the analysis section I explorethe practical applicability of the framework by using the same empirical casestudies as in Chapter 5. The final section suggests four propositions for furtherresearch.   The last empirical study is presented in Chapter 7. There I construct aframework of management, learning and implementation in response to crisis.My point of departure is a proposition from previous crisis managementresearch which posits that previous experience can shape crisis response as away of repeating former routines or as a precondition for improvisation. Thekey research question is: How do organizational management structures affect crisis response, learning and implementation? In the study I argue that flexibilityis closely connected to the way organizations learn – in behavioral or cognitivemodes. Moreover, these learning modes are connected to the role of managerialgroups, where I differentiate between centralized and decentralized top managerialgroups. In addition, two case studies of how two bureaucratic media organizations(Sveriges Radio and SVT) managed and learned from extraordinarynews events – most notably 9/11 and the assassination of the Swedish ForeignMinister Anna Lindh – are conducted. The findings show how the decentralizedmanagerial group learned in a behavioral fashion, by creating new formalpolicies and structures, while organizational members in the centralized managerialgroup relied on individual cognitive structures as a way of ‘storing’ lessonslearned. The study ends by discussing the findings from a crisis managementperspective, where I propose that the two modes of learning profoundly affectthe crucial issue of flexibility in organizational crisis response.The concluding Chapter 8 discusses and contrasts the findings and propositionsgenerated from the four separate empirical analyses. Here the role oforganizational structure and culture are highlighted by revisiting specific organizationalfactors that seem to impact on organizational crisis management andlearning processes, such as previous experience, flexibility and rigidity in crisisresponse and learning, and centralization and decentralization. These factorswere also outlined in the literature review. Further empirical evidence of howthe factors affect crisis response and crisis learning in organizations was foundin the four empirical analyses.   In addition, findings from the empirical studies also related to different types of learning processes such as intra- and intercrisis learning and singleand double-loop learning. Consequently these concepts are also deliberated upon in the concluding sections of the dissertation. As a final attempt to bring the propositions and arguments together, a framework of the crisis management and learning process is proposed. In regard to this venture, it is important to acknowledge the limitations of the framework, and of the dissertation as a whole. As it is only based on data from six cases of Swedish public organizational responses to crisis, the framework is merely a visual schematic of a number of propositions to be further tested and validated by further research. However, the framework also has a few virtues. It is an attempt to approach the ambiguous nature of crises and crisis management processes. The framework may also assist in providing more sensible and practical conceptualizations, and thus bring us closer to definitions that remain close to everyday operations of practitioners involved in crisis management. This dissertation thus makes an effort to bridge the gap between crisis management scholars and practitioners. This is also an overall goal guiding research activities at the National Center for Crisis Management Studies (CRISMART) at the Swedish National Defence College, where the research behind this dissertation has been conducted.

The aim of this paper is to investigate if a revaluation of the Chinese renminbi is in China’s interest and whether or not a renminbi revaluation can contribute to correct the US current account deficit. For that purpose, advantages and disadvantages of a revaluation for China are discussed. Furthermore, the fundamental causes of the US current account deficit are analysed to evaluate to what extent a renminbi revaluation can correct this imbalance. The discussion is based on previous research in this area. The main result is that a revaluation of the Chinese renminbi is primarily beneficial for China. Additionally it is found that the fundamental causes of the US current account deficit are domestic macroeconomic conditions and not China’s exchange rate policy. Nevertheless, a renminbi revaluation can help to support to correct the imbalance situation. As evidence is found that a revaluation is beneficial for China, it is further analysed how the revaluation should be practically obtained. The basic result is that the renminbi revaluation should be initiated by more exchange rate flexibility rather than by a one-step appreciation.

University of Örebro Department of social Sciences Sociology, Contnuation Course, 61-90hp. Essay 15hp. Spring 2008 Title: Who is resbonsible? A soceityscientific discussion about burnout. Author: Emilie Fuchs Abstract The purpose with this essay is to do a critical comparation between two different perspectives, burnout as an individual problem and burnout as a social problem. The first perspective states that the individual itself is responsible for her sickness while the second perspective states that the society and foremost the labour market should work in order to prevent people from beeing burned out. With that purpose in mind I want to enlighten and hopefully bring up the topic for discussion. The essay is based upon the following questions: • How can you sociologically understand the labour market of today? • How can you understand burnout in an individual context? • How can you understand burnout in a social context? By studying and reading four books, I have presented the two different perspectives of burnout. Two books represents burnout out of a social perspective whereas the individual perspective is advocated in the other two books. The results founded shows that the individual perspective means that the individual has to resolve his own problems even though the labour market is the main cause to why people becomes burned out. The social perspective, on the other hand, basically want the labour market to take responsibility and prevent burnouts. Through the results, my conclusion is that the individual perspective represents the individualised world we live in. The social perspective of burnout shows the importance of a good solidarity, mainly at work. This point of view could probably lead to a growing safety on the labour market, which presumably results in less burned out people. There are, after reading this essay, a few questions the reader may ask herself: Should not the society take responsibility and help those who are burned out? Does the structure of society contribute to the fact that people becomes burned out? Keywords: Burnout, Individual, Society, Work, Flexibility / Sammanfattning Syftet med uppsatsen är att göra en kritisk jämförelse av två olika perspektiv, utbrändhet som ett individuellt problem och utbrändhet som ett samhälleligt problem. Det första perspektivet menar att individen själv ansvarar för om hon blir sjuk eller inte medan det andra perspektivet är av den åsikten att samhället och främst arbetsmarkanden ska arbeta för att människor inte ska bli utbrända. Med hjälp av detta syfte ska problemet utbrändhet belysas och förhoppningsvis få upp ämnet till diskussion. Denna uppsats baseras på följande frågeställningar: • Hur kan man sociologiskt förstå dagens arbetsmarknad? • Hur går det att förstå utbrändheten i en individuell kontext? • Hur kan man förstå utbrändheten i en samhällelig kontext? Genom att studera och läsa fyra böcker har jag presenterat de två olika perspektiven av utbrändhet. Två böcker representerar utbrändhet ur ett samhälleligt perspektiv medan det individuella perspektivet förespråkas i de andra två böckerna. De resultaten jag har fått fram visar att det individuella perspektivet menar att individen själv ska lösa och ta tag i sina problem trots att arbetsmarknaden är huvudorsaken till att vi människor blir utbrända. Det samhälleliga perspektivet är av den åsikten att arbetsmarkanden, och samhället till viss del, ska ta ansvar och hjälpa individen. Individen ska i viss mån också själv förebygga och komma ur sin utbrändhet. Genom resultatet har jag kunnat dra slutsatsen att det individuella perspektivet representerar den individualiserade värld som vi lever i. Det andra synsättet på utbrändhet visar vikten av att vi har en bra sammanhållning i främst arbetet, vilket leder till en trygghet som gör att vi inte kommer att ha lika stor mängd sjuka. Efter att ha läst denna uppsats kan exempelvis följande frågor ställas: Borde inte hela samhället ta ett ansvar och hjälpa de som är utbrända? Är det de samhällsstrukturer vi lever i som bidrar till att vi blir utbrända? Nyckelord: Utbrändhet, Individ, Samhälle, Arbete, Flexibilitet

Although several scholars have argued that the spouses failure to adjust is one of the main reasons expatriate employees return prematurely from international assignments, research about spouse adjustment is scarce, and existing research about the phenomenon was conducted almost two decades ago. Therefore, our research was conducted in order to empirically examine theoretical variables that historically relate to host country adjustment of the spouse in order to see if these variables are still valid today. The present study focused on personality, family characteristics and anticipatory and in-country adjustment variables of the intercultural adjustment of expatriate spouses. Among a sample of 105 expatriate spouses it was shown that the variables measuring time in host-country, positive pre-move opinion held by the spouse, living conditions at least equal to home, cultural novelty, personality traits, and family cohesion were significant moderators of the adjustment to the new country of the spouse. We could also show that the adjustment of the spouse affects the adjustment of the expatriate, thus increasing the relevance for companies to aim more attention to the spouse well-being. An area for future research could be to investigate more closely if there is different effectiveness of different types of training.

Background: The current study investigated the efficacy of a novel virtual reality-cognitive rehabilitation (VR-CR) intervention to improve contextual processing of objects in children with autism. Contextual processing is a cognitive ability thought to underlie the social and communication deficits of autism. Previous research supports that children with autism show deficits in contextual processing, as well as deficits in its basic component abilities: abstraction and cognitive flexibility. Methods: Four children with autism participated in a multiple baseline single-subject study. The children were taught how to see objects in context by reinforcing attention to pivotal contextual information. One-on-one teaching sessions occurred three times per week for approximately two weeks. Results: All children demonstrated significant improvements in contextual processing and cognitive flexibility. Mixed results were found on the control test. Changes in context-related behaviours were reported. Conclusions: Further studies using virtual reality to target specific cognitive impairments in children with autism are warranted.

Background: In recent research literature, some researchers mean that companies in fast changing markets have to act proactively while others find that companies have to adapt to conditions and to react. This makes it interesting to study how software companies act strategically and also to study to what extent a flexible organisation is required by companies who proact and by those who react. Purpose: The purpose of this thesis is the study how different types of software companies act strategically and what this requires of the company in terms of flexibility. Delimitation: The study treats only Swedish software companies with more than ten employees. Proceed of the Study: Representatives from four case companies as well as a consultant have been interviewed. As a complement to the case study, a survey has also been conducted where 36 companies have participated. Results: Only one of the four case companies can be said to act proactively. Among the survey companies, there are principally young companies, companies with a leading position on the market and companies that experience high growth that act proactively. Companies that work proactively value to a greater extent than reactive companies a flexibility that is created by visions.

Background: The current study investigated the efficacy of a novel virtual reality-cognitive rehabilitation (VR-CR) intervention to improve contextual processing of objects in children with autism. Contextual processing is a cognitive ability thought to underlie the social and communication deficits of autism. Previous research supports that children with autism show deficits in contextual processing, as well as deficits in its basic component abilities: abstraction and cognitive flexibility. Methods: Four children with autism participated in a multiple baseline single-subject study. The children were taught how to see objects in context by reinforcing attention to pivotal contextual information. One-on-one teaching sessions occurred three times per week for approximately two weeks. Results: All children demonstrated significant improvements in contextual processing and cognitive flexibility. Mixed results were found on the control test. Changes in context-related behaviours were reported. Conclusions: Further studies using virtual reality to target specific cognitive impairments in children with autism are warranted.

Tendencies such as the increasing spread of market globalisation, new technological developments, the reduction of product life cycles and aggressive competition, are generating high levels of environmental changes and uncertainty for organisations of all types (Volberda, 1996; Sanchez, 1997). These circumstances require rapid responses through adaptations of organisational attitudes and capabilities, which lead to innovative management approaches and organisational methods (Bueno, 1996: 262). Traditional sources of competitive advantages are changing and it is imperative to deploy new strategies to successfully compete under changing external conditions. For example, flexibility is emerging as a competitive weapon that allows organisations to counteract current market evolution and competitive levels (Ahmed et al., 1996; Volberda, 1996). Flexibility is a broad concept that can refer to operational issues such as manufacturing flexibility, or to strategic decisions such as alterations in the organisation's product-market combinations. All these factors are associated with the organisation's efforts to adjust available means to external challenges. Regardless of the specific response adopted by organisations, it is broadly believed that environmental dynamism forces managers to pay increasing attention to the management of the organisation's social issues (Wright and Snell, 1998). From a managerial point of view, human resource management activities used by organisations in the new competitive landscape are changing. This can be seen, for example, in job descriptions. Nowadays individual contributions to organisational goals are being substituted by team accomplishments. Furthermore, technological advances (e.g. the introduction of Internet in companies) are making it difficult to assess and manage employee performance in the workplace. As a result High Commitment Management (HCM) is emerging as the optimal system to manage the employment relationships in modern organisations. HCM is a particular approach to human resources management characterised by certain features such as the emphasis on the development of employee skills, job enrichment and the provision of equitable incentives. A number of authors in recent decades have demonstrated the impact of HCM on organisational outcomes. From an employee-based perspective, organisations require a new type and level of contribution from their workforce. In order to successfully compete under dynamic conditions, people's performance of a fixed set of prescribed tasks is no longer considered adequate. Instead, competitive advantage comes from employees who are engaged in broad open-ended and interdependent roles (Campbell, 2000; Parker, 2000). In sum, from an individual perspective, human resource flexibility is a key success factor in current competitive environments. However, to date no accepted definition of human resource flexibility has been put forward; attempts should be made to provide this concept with a more solid theoretical background (Looise et al., 1998). In this study, I propose a conceptualisation of HR flexibility based on the premises of the Resource-Based View of the firm (RBV) (Wernerfelt, 1984; Barney, 1991; Amit and Shoemaker, 1993). Similarly to the role that value, rareness, inimitability and non-substitutability play in the consideration of resources as strategic assets (Barney, 1991), flexible resources are characterised by certain features, such as their applicability to a variety of uses or the ease with which they can be modified (Sanchez, 1995). One of the aims of this research is to apply these concepts to the conceptualisation of human resource flexibility.All things considered, social factors are essential to the successful deployment of organisational flexibility, as are the activities used to manage employees (Dyer and Shafer, 1999). Not only are individual responsibilities different in dynamic environments, but also the human resource activities used by organisations to manage their workforce will alter. The present study focuses on these two questions and analyses their interrelationships.The general purpose of this research is to examine the contribution of HCM to organisational performance by considering the role that human resource flexibility plays in this relationship. That is, I question whether a high commitment approach is important to determine the workforce's flexibility and to what extent a flexible workforce enhances organisational outcomes.

De acuerdo con la literatura científica, la frecuencia del acortamiento de los isquiotibiales, está relacionado con factores genéticos, hábitos diarios y actividades deportivas. Sin embargo, con las numerosas metodologías de tratamiento propuestas en la literatura se hace difícil establecer cuál de ellas resulta ser la más efectiva. En este trabajo se llevó a cabo meta-análisis sobre la eficacia de los tratamientos para la ganancia de flexibilidad en los músculos isquiotibiales. La búsqueda de la literatura permitió identificar 41 estudios, 39 publicados y 2 no publicados, entre 1930 y 2007, que cumplieron con los criterios de inclusión, totalizando 85 comparaciones entre grupo tratado y control. El índice del tamaño del efecto utilizado fue la diferencia de medias estandarizada. Los tratamientos obtuvieron una efectividad estadísticamente significativa (d+ = 1,054). El estiramiento muscular, más la combinación de estiramiento más calentamiento resultaron ser los tratamientos más efectivos. La relación entre el tamaño del efecto con las demás variables de tratamiento, de sujeto, metodológicas y extrínsecas, también fueron examinadas. El sesgo de publicación no fue una amenaza contra la validez de los resultados. Los tratamientos son más eficaces cuando: son empleados en sujetos del género femenino; cuanto más jóvenes sean los sujetos; y cuando se utiliza un número mayor de semanas de tratamiento. / According to the scientific literature, the frequency of the shortened hamstring, is related to genetic factors, daily habits and sports activities. In spite of the found treatment methodologies diversity is difficult to establish which of them is more effective. In this paper we carried out a meta-analysis about the efficacy of the treatment for the increase the flexibility in the hamstring muscle. The searched of the literature enabled us identify 41 studies, 39 published and 2 no published, between 1930 and 2007, that fulfilled our the selection criteria, giving a total 85 comparisons between a treated an a control group. The effect size index was the standardized mean difference in the posttest. The treatments obtained a statistically significant effectiveness (d+ = 1,054). The stretching and stretching plus warming -up resulted to be the treatment more effective. The relationship of others treatment, subjects, methodological and extrinsic variables with the effect size were also examined. The publication bias was not a threat against the validity of the results. The treatments are more efficient when: they are applied in subjects of the feminine gender; the more young be the subjects and when a greater number of weeks of treatment are utilized