190 research outputs found

    Heterogeneity in Consumer Price Stickiness: A Microeconometric Investigation.

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    This paper examines heterogeneity in price stickiness using a large, original, set of individual price data collected at the retail level for the computation of the French CPI. To that end, we estimate, at a very high level of disaggregation, competing-risks duration models that distinguish between price increases, price decreases and product replacements. The main .ndings are the following: i) cross-product and cross-outlet-type heterogeneity in both the shape of the hazard function and the impact of covariates is pervasive ii) at the product-outlet type level, the baseline hazard function of a price spell is non-decreasing iii) there is strong evidence of state-dependence, especially for price increases.Sticky prices ; Heterogeneity ; Hazard function ; Duration models.

    Gas permeation through a polymer network

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    We study the diffusion of gas molecules through a two-dimensional network of polymers with the help of Monte Carlo simulations. The polymers are modeled as non-interacting random walks on the bonds of a two-dimensional square lattice, while the gas particles occupy the lattice cells. When a particle attempts to jump to a nearest-neighbor empty cell, it has to overcome an energy barrier which is determined by the number of polymer segments on the bond separating the two cells. We investigate the gas current JJ as a function of the mean segment density ρ\rho, the polymer length ℓ\ell and the probability qmq^{m} for hopping across mm segments. Whereas JJ decreases monotonically with ρ\rho for fixed ℓ\ell, its behavior for fixed ρ\rho and increasing ℓ\ell depends strongly on qq. For small, non-zero qq, JJ appears to increase slowly with ℓ\ell. In contrast, for q=0q=0, it is dominated by the underlying percolation problem and can be non-monotonic. We provide heuristic arguments to put these interesting phenomena into context.Comment: Dedicated to Lothar Schaefer on the occasion of his 60th birthday. 11 pages, 3 figure

    The striatal dopamine transporter in first-episode, drug-naive schizophrenic patients: evaluation by the new SPECT-ligand[99mTc]TRODAT-1

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    Following the current hypothesis that acute schizophrenic psychotic illness is associated with a triatal ‘hyperdopaminergic state’, presynaptic integrity and dopamine transporter (DAT) density in first-episode, neuroleptic-naive schizophrenic patients was measured by single-photonemission- tomography (SPECT) and compared with that in healthy control subjects. A new SPECT-ligand for assessment of the striatal DAT, the Technetium-99m-labelled tropane TRODAT-1 ([99mTc]TRODAT-1), was used. Ten inpatients suffering from a first acute schizophrenic episode and 10 age- and sex-matched healthy control subjects underwent SPECT with [99mTc]TRODAT-1. On the day of SPECT, psychopathological ratings were performed with the Brief Psychiatric Rating Scale (BPRS), the Positive and Negative Syndrome Scale (PANSS) and Schedule for Assessment of Negative Symptoms (SANS). Patients had not previously received any neuroleptic or antidepressant medication. Mean specific TRODAT-1 binding in the striatum did not differ significantly between the patient and the age- and sex-matched control group (1.25 vs. 1.28). Variance was significantly higher in the patient group. The data obtained with the new ligand in first-episode, drug-naive schizophrenic patients are in line with the PET results from the group of Laakso et al. in a comparable patient sample. [99mTc]TRODAT-1 seems to be a valuable new SPECTligand in the evaluation of the presynaptic site of the striatal dopaminergic synapse in schizophrenia

    T1 and FLAIR signal intensities are related to tau pathology in dominantly inherited Alzheimer disease

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    Carriers of mutations responsible for dominantly inherited Alzheimer disease provide a unique opportunity to study potential imaging biomarkers. Biomarkers based on routinely acquired clinical MR images, could supplement the extant invasive or logistically challenging) biomarker studies. We used 1104 longitudinal MR, 324 amyloid beta, and 87 tau positron emission tomography imaging sessions from 525 participants enrolled in the Dominantly Inherited Alzheimer Network Observational Study to extract novel imaging metrics representing the mean (Ο) and standard deviation (σ) of standardized image intensities of T1-weighted and Fluid attenuated inversion recovery (FLAIR) MR scans. There was an exponential decrease in FLAIR-Ο in mutation carriers and an increase in FLAIR and T1 signal heterogeneity (T1-σ and FLAIR-σ) as participants approached the symptom onset in both supramarginal, the right postcentral and right superior temporal gyri as well as both caudate nuclei, putamina, thalami, and amygdalae. After controlling for the effect of regional atrophy, FLAIR-Ο decreased and T1-σ and FLAIR-σ increased with increasing amyloid beta and tau deposition in numerous cortical regions. In symptomatic mutation carriers and independent of the effect of regional atrophy, tau pathology demonstrated a stronger relationship with image intensity metrics, compared with amyloid pathology. We propose novel MR imaging intensity-based metrics using standard clinical T1 and FLAIR images which strongly associates with the progression of pathology in dominantly inherited Alzheimer disease. We suggest that tau pathology may be a key driver of the observed changes in this cohort of patients

    United Kingdom Fund Managers and Institutional Investors’ Attitudes Toward Japanese Equities

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    This article explores UK fund managers and institutional investors' attitudes toward Japanese equities. We find a declining home bias of UK pension funds vis-à-vis Japanese equities since the early 1990s. However, for the most part, this decrease is a reflection of Japan's decreasing equity market and gross domestic product weights. Only in the 2000s did UK pension funds increase their Japanese equity holdings slightly. While our informants showed a comparatively high degree of variance in opinions about market factors, certain macro and institutional factors—namely, economic growth, deflation, demographics, and corporate governance—were rated high as explanatory factors for an overall low enthusiasm in Japanese equities. Our discussion confirms that these factors appear to make investments in Japan comparatively less attractive

    Beyond crime statistics: the construction and application of a criminogenity monitor in Amsterdam

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    Criminologists have devoted a great deal of attention to risk factors - also called criminogenic factors - leading to criminal offending. This paper presents a criminogenity monitor which includes 19 risk factors that underlie crime. These factors do not themselves cause criminal behaviour; rather, they must be seen as signals that crimes may be committed. After discussing how the criminogenity monitor was constructed, we apply the risk factors we examined to the situation in Amsterdam, capital city of the Netherlands. The monitor is intended to function particularly as an instrument to rationalise policy-makers' work in targeting and preventing symptoms of crime at three geographical levels: the entire city, its boroughs and its neighbourhoods. Š 2012 The Author(s)

    Amino-acid PET versus MRI guided re-irradiation in patients with recurrent glioblastoma multiforme (GLIAA) – protocol of a randomized phase II trial (NOA 10/ARO 2013-1)

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    Background: The higher specificity of amino-acid positron emission tomography (AA-PET) in the diagnosis of gliomas, as well as in the differentiation between recurrence and treatment-related alterations, in comparison to contrast enhancement in T1-weighted MRI was demonstrated in many studies and is the rationale for their implementation into radiation oncology treatment planning. Several clinical trials have demonstrated the significant differences between AA-PET and standard MRI concerning the definition of the gross tumor volume (GTV). A small single-center non-randomized prospective study in patients with recurrent high grade gliomas treated with stereotactic fractionated radiotherapy (SFRT) showed a significant improvement in survival when AA-PET was integrated in target volume delineation, in comparison to patients treated based on CT/MRI alone. Methods: This protocol describes a prospective, open label, randomized, multi-center phase II trial designed to test if radiotherapy target volume delineation based on FET-PET leads to improvement in progression free survival (PFS) in patients with recurrent glioblastoma (GBM) treated with re-irradiation, compared to target volume delineation based on T1Gd-MRI. The target sample size is 200 randomized patients with a 1:1 allocation ratio to both arms. The primary endpoint (PFS) is determined by serial MRI scans, supplemented by AA-PET-scans and/or biopsy/surgery if suspicious of progression. Secondary endpoints include overall survival (OS), locally controlled survival (time to local progression or death), volumetric assessment of GTV delineated by either method, topography of progression in relation to MRIor PET-derived target volumes, rate of long term survivors (> 1 year), localization of necrosis after re-irradiation, quality of life (QoL) assessed by the EORTC QLQ-C15 PAL questionnaire, evaluation of safety of FET-application in AA-PET imaging and toxicity of re-irradiation. Discussion: This is a protocol of a randomized phase II trial designed to test a new strategy of radiotherapy target volume delineation for improving the outcome of patients with recurrent GBM. Moreover, the trial will help to develop a standardized methodology for the integration of AA-PET and other imaging biomarkers in radiation treatment planning. Trial registration: The GLIAA trial is registered with ClinicalTrials.gov (NCT01252459, registration date 02.12.2010), German Clinical Trials Registry (DRKS00000634, registration date 10.10.2014), and European Clinical Trials Database (EudraCT-No. 2012-001121-27, registration date 27.02.2012)

    Moving Beyond Mimicry: Developing Hybrid Spaces in Indian Business Schools

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    This article analyses the identity work of Indian management educators and scholars as they seek to establish, maintain and revise a sense of self in the context of business school globalization. We show how globalization, combined with the historical legacy of colonialism, renders Indian scholars precarious in their interactions with Western business schools. Based on a qualitative interview study, we explore how Indian business school scholars perform their identities in the context of neo-colonial relations, which are characterised by the dominance of English language and a pressure to conform to research norms set by globally-ranked journals. Drawing on postcolonial theory, our argument focuses on mimicry as a distinctive form of identity work that involves maintaining difference between Western and non-Western identities by 'Othering' Indian scholars, while simultaneously seeking to transform them. We draw attention to ambivalence within participants' accounts, which we suggest arises because the authority of Western scholarship relies on maintaining non-Western scholars in a position of alterity or 'not quite-ness'. We suggest that hybridity offers an opportunity to disrupt and question current practices of business school globalization and facilitate scholarly engagement that reflects more diverse philosophical positions and worldviews

    Synthesising Corporate Responsibility on Organisational and Societal Levels of Analysis: An Integrative Perspective

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    This article develops an integrative perspective on corporate responsibility by synthesising competing perspectives on the responsibility of the corporation at the organisational and societal levels of analysis. We review three major corporate responsibility perspectives, which we refer to as economic, critical, and politico-ethical. We analyse the major potential uses and pitfalls of the perspectives, and integrate the debate on these two levels. Our synthesis concludes that when a society has a robust division of moral labour in place, the responsibility of a corporation may be economic (as suggested under the economic perspective) without jeopardising democracy and sustainability (as reported under the critical perspective). Moreover, the economic role of corporations neither signifies the absence of deliberative democratic mechanisms nor business practices extending beyond compliance (as called for under the politico-ethical perspective). The study underscores the value of integrating different perspectives and multiple levels of analysis to present comprehensive descriptions and prescriptions of the responsibility phenomenon
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