3499 research outputs found
Sort by
From La Bohème to La Wally: How Organizational Status Affects the (Un)conventionality of Opera Repertoires
No full textIn this paper we examine the relationship between organizational status and nonconformity in complex institutional fields characterized by the enduring tension between divergent institutional logics. First, we hypothesize the existence of an inverted U-shaped (IUS) relationship between status and nonconformity. Second, we argue that legitimacy and celebrity enhancing signals, that complement the external perception of a firm’s market identity, moderate the relationship between status and nonconformity, by springing up or inhibiting opportunities for firms to protect vs. raise their status position through high status patterns of affiliations. Specifically, we argue that while celebrity enhancing efforts reinforce middle status nonconformist behaviors by emphasizing the exceptional and positive valence of their nonconformist undertakings, legitimacy enhancing signals constraint middle status deviant behaviors and reverse the IUS curve. Unveiling the taken-for-granted traits of their identities hampers middle status ambition to raise the social hierarchy through nonconformity but fosters low and high status freedom of deviance through a reinforced security in their social position. We found strong support for our arguments in statistical analysis of 42 Italian opera houses repertoires from 2004 to 2011.
We synthesize our findings by offering an integrated framework on how the interplay between status, legitimacy and celebrity enhancing signals affects organizations’ ability to depart from established institutional frameworks under conditions of institutional complexity
The ghosts of the past, present and future: the case of the Army Headquarters in Belgrade, Serbia
No full textAbstractWhen the construction of Dobrović's Army Headquarters in Belgrade, Serbia was finally finished in 1965, at a location continuously designated for the Army, it was thought that it would serve its purpose in a secured future, the socialist one. And it was thought that it would house the leadership of the Army, which was seen as the rightful heir of the most glorious examples of military tradition from the Second World War. With his building Dobrović filled the void left by the WWII, but he also left a true mystery – how to interpret it. Long after the date of inception, in 1960, he offered two clues, the philosophical one – through the Bergson's dynamic schemes and the void as the central dynamizing element of the composition and the symbolically appropriate one – through the story of the Sutjeska canyon. In this way he allowed everyone to find a reading suitable for them. But when the system changed, followed by a decrease in size of both the State and the Army, the question of the dual reading, which functioned so perfectly, suddenly became the cause of conflicts, conflicts of a more profound nature than ever before. Even in these changed circumstances the building performed its function, until the 1999 NATO aggression, when it was, although empty, bombed several times. The history repeated itself and this location once again experienced bombardment which left disturbing ruins, voids and shattered identities, in need of renegotiation. How to interpret a building from a socialist period in a society which is both post-socialist and post-conflict? How to find peace with the ghosts of the past, present and future, which permeate both the location and the building? How to approach different narratives surrounding the physical structure destroyed by war and considered as heritage even before those events, although officially listed only after the ruination and cessation of use. Those are the main subjects of this article
A unified framework for differential aggregations in Markovian process algebra
No full textFluid semantics for Markovian process algebra have recently emerged as a computationally attractive approximate way of reasoning about the behaviour of stochastic models of large-scale systems. This interpretation is particularly convenient when sequential components characterised by small local state spaces are present in many independent copies. While the traditional Markovian interpretation causes state-space explosion, fluid semantics is independent from the multiplicities of the sequential components present in the model, just associating a single ordinary differential equation (ODE) with each local state. In this paper we analyse the case of a process algebra model inducing a large ODE system. Previous work, known as exact fluid lumpability, requires two symmetries: ODE aggregation is possible for processes that i) are isomorphic and that ii) are present with the same multiplicities. We first relax the latter requirement by introducing the notion of ordinary fluid lumpability, which yields an ODE system where the sum of the aggregated variables is preserved exactly. Then, we consider approximate variants of both notions of lumpability which make nearby processes symmetric after a perturbation of their parameters. We prove that small perturbations yield nearby differential trajectories. We carry out our study in the context of a process algebra that unifies two synchronisation semantics that are well studied in the literature, useful for the modelling of computer systems and chemical networks, respectively. In both cases, we provide numerical evidence which shows that, in practice, many heterogeneous processes can be aggregated with negligible errors
Data-driven feature learning for myocardial segmentation of CP-BOLD MRI
No full textCardiac Phase-resolved Blood Oxygen-Level-Dependent (CP-BOLD) MR is capable of diagnosing an ongoing ischemia by detecting changes in myocardial intensity patterns at rest without any contrast and stress agents. Visualizing and detecting these changes require significant post-processing, including myocardial segmentation for isolating the myocardium. But, changes in myocardial intensity pattern and myocardial shape due to the heart’s motion challenge automated standard CINE MR myocardial segmentation techniques resulting in a significant drop of segmentation accuracy. We hypothesize that the main reason behind this phenomenon is the lack of discernible features. In this paper, a multi scale discriminative dictionary learning approach is proposed for supervised learning and sparse representation of the myocardium, to improve the myocardial feature selection. The technique is validated on a challenging dataset of CP-BOLD MR and standard CINE MR acquired in baseline and ischemic condition across 10 canine subjects. The proposed method significantly outperforms standard cardiac segmentation techniques, including segmentation via registration, level sets and supervised methods for myocardial segmentation
Estimating topological properties of weighted networks from limited information
No full textA problem typically encountered when studying complex systems is the limitedness of the information available on their topology, which hinders our understanding of their structure and of the dynamical processes taking place on them. A paramount example is provided by financial networks, whose data are privacy protected: Banks publicly disclose only their aggregate exposure towards other banks, keeping individual exposures towards each single bank secret. Yet, the estimation of systemic risk strongly depends on the detailed structure of the interbank network. The resulting challenge is that of using aggregate information to statistically reconstruct a network and correctly predict its higher-order properties. Standard approaches either generate unrealistically dense networks, or fail to reproduce the observed topology by assigning homogeneous link weights. Here, we develop a reconstruction method, based on statistical mechanics concepts, that makes use of the empirical link density in a highly nontrivial way. Technically, our approach consists in the preliminary estimation of node degrees from empirical node strengths and link density, followed by a maximum-entropy inference based on a combination of empirical strengths and estimated degrees. Our method is successfully tested on the international trade network and the interbank money market, and represents a valuable tool for gaining insights on privacy-protected or partially accessible systems
Enhancing the evaluation of pathogen transmission risk in a hospital by merging hand-hygiene compliance and contact data: a proof-of-concept study
No full textBACKGROUND:Hand-hygiene compliance and contacts of health-care workers largely determine the potential paths of pathogen transmission in hospital wards. We explored how the combination of data collected by two automated infrastructures based on wearable sensors and recording (1) use of hydro-alcoholic solution and (2) contacts of health-care workers provide an enhanced view of the risk of transmission events in the ward. METHODS:We perform a proof-of-concept observational study. Detailed data on contact patterns and hand-hygiene compliance of health-care workers were collected by wearable sensors over 12days in an infectious disease unit of a hospital in Marseilles, France.RESULTS:10,837 contact events among 10 doctors, 4 nurses, 4 nurses' aids and 4 housekeeping staff were recorded during the study. Most contacts took place among medical doctors. Aggregate contact durations were highly heterogeneous and the resulting contact network was highly structured. 510 visits of health-care workers to patients' rooms were recorded, with a low rate of hand-hygiene compliance. Both data sets were used to construct histories and statistics of contacts informed by the use of hydro-alcoholic solution, or lack thereof, of the involved health-care workers. CONCLUSIONS:Hand-hygiene compliance data strongly enrich the information concerning contacts among health-care workers, by assigning a 'safe' or 'at-risk' value to each contact. The global contact network can thus be divided into 'at-risk' and 'safe' contact networks. The combined data could be of high relevance for outbreak investigation and to inform data-driven models of nosocomial disease spread
A topographical organization for action representation in the human brain
No full textHow the human brain represents distinct motor features into a unique finalized action still remains undefined. Previous models proposed the distinct features of a motor act to be hierarchically organized in separated, but functionally interconnected, cortical areas. Here, we hypothesized that distinct patterns across a wide expanse of cortex may actually subserve a topographically organized coding of different categories of actions that represents, at a higher cognitive level and independently from the distinct motor features, the action and its final aim as a whole. Using functional magnetic resonance imaging and pattern classification approaches on the neural responses of 14 right-handed individuals passively watching short movies of hand-performed tool-mediated, transitive, and meaningful intransitive actions, we were able to discriminate with a high accuracy and characterize the category-specific response patterns. Actions are distinctively coded in distributed and overlapping neural responses within an action-selective network, comprising frontal, parietal, lateral occipital and ventrotemporal regions. This functional organization, that we named action topography, subserves a higher-level and more abstract representation of finalized actions and has the capacity to provide unique representations for multiple categories of actions. Hum Brain Mapp 36:3832–3844, 2015. © 2015 Wiley Periodicals, Inc
Price Dynamics of Agricultural Commodities: Evidence from Turkey
No full textFarmers at the beginning and consumers at the end of the marketing chain often suspect that imperfect competition in processing and retailing allows middlemen to abuse market power. Therefore, the existences of price asymmetries indicate an unbalanced relationship between increases and decreases for a product through the farm gate and retail stages. Price transmission can be defined as the relationship between prices in two related markets. Price transmission is used to demonstrate the effects of a price change in one market over another and provides information on the extent of markets. The special interest is whether the transmission is symmetric or asymmetric. A symmetric price transmission integrates markets vertically and horizontally and a change in prices in one market quickly reflected to another. But, if the price transmission between the specific stages of the supply chain is asymmetric, then the price changes at the production level are not passed to price changes at the processing and/or retail level quickly or fully as in the case of a symmetric transmission. Most publications on asymmetric price transmission refer to non-competitive market structures as an explanation for asymmetry. Market power and oligopolistic behavior can cause imperfect price transmission (Vavra and Goodvin 2005). Brown & Yücel (2000) consider oligopolistic firms that engage in unspoken collusion to maintain higher profits. Ward (1982) suggests that market power can lead to negative APT if oligopolists are reluctant to risk losing market share by increasing output prices. Market power would appear to be capable of leading to long lasting asymmetries in the magnitude of adjustment (Meyer Craubadel 2004:590). Therefore, the aim of the study is to test for raw milk and retail fluid milk price transmission in Turkey by employing the method of cointegration in the presence of asymmetric error correction. In analyzing the historical data, evidence on price transmission for liquid milk have been considered. Monthly data between 2005-2014 for retail and raw milk prices are used. M-Tar and Tar and standard EG model of cointegration techniques are applied in order to capture the possible asymmetric relations
Design and simulation of an optimized e-linac based neutron source for {BNCT} research
No full textAbstract The paper is focused on the study of a novel photo-neutron source for {BNCT} preclinical research based on medical electron Linacs. Previous studies by the authors already demonstrated the possibility to obtain a mixed thermal and epithermal neutron flux of the order of 107 cm−2 s−1. This paper investigates possible Linac’s modifications and a new photo-converter design to rise the neutron flux above 5 107 cm−2 s−1, also reducing the gamma contamination
Reconciling White-Box and Black-Box Perspectives on Behavioral Self-adaptation
No full textThis paper proposes to reconcile two perspectives on behavioral adaptation commonly taken at different stages of the engineering of autonomic computing systems. Requirements engineering activities often take a black-box perspective: A system is considered to be adaptive with respect to an environment whenever the system is able to satisfy its goals irrespectively of the environment perturbations. Modeling and programming engineering activities often take a white-box perspective: A system is equipped with suitable adaptation mechanisms and its behavior is classified as adaptive depending on whether the adaptation mechanisms are enacted or not. The proposed approach reconciles black- and white-box perspectives by proposing several notions of coherence between the adaptivity as observed by the two perspectives: These notions provide useful criteria for the system developer to assess and possibly modify the adaptation requirements, models and programs of an autonomic system