314 research outputs found

    Entry and Exit in a Liberalised Market.

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    We analyze the determinants of entry and exit in the European Airline Markets in the post-liberalization period. Unlike previous studies, we find that the presence of charter or seasonal operators and the level of quality provided by the incumbents are relevant to explain entry and exit. Differential traits in the main low cost airlines' entry and exit behavior are also analysed.Entry, Exit, Airlines, Conditional Logit

    Facing challenges in differential classical conditioning research: benefits of a hybrid design for simultaneous electrodermal and electroencephalographic recording

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    Several challenges make it difficult to simultaneously investigate central and autonomous nervous system correlates of conditioned stimulus (CS) processing in classical conditioning paradigms. Such challenges include, for example, the discrepant requirements of electroencephalography (EEG) and electrodermal activity (EDA) recordings with regard to multiple repetitions of conditions and sufficient trial duration. Here, we propose a MultiCS conditioning set-up, in which we increased the number of CSs, decreased the number of learning trials, and used trials of short and long durations for meeting requirements of simultaneous EEG–EDA recording in a differential aversive conditioning task. Forty-eight participants underwent MultiCS conditioning, in which four neutral faces (CS+) were paired four times each with aversive electric stimulation (unconditioned stimulus) during acquisition, while four different neutral faces (CS−) remained unpaired. When comparing after relative to before learning measurements, EEG revealed an enhanced centro-posterior positivity to CS+ vs. CS− during 368–600 ms, and subjective ratings indicated CS+ to be less pleasant and more arousing than CS−. Furthermore, changes in CS valence and arousal were strong enough to bias subjective ratings when faces of CS+/CS− identity were displayed with different emotional expression (happy, angry) in a post-experimental behavioral task. In contrast to a persistent neural and evaluative CS+/CS− differentiation that sustained multiple unreinforced CS presentations, electrodermal differentiation was rapidly extinguished. Current results suggest that MultiCS conditioning provides a promising paradigm for investigating pre–post-learning changes under minimal influences of extinction and overlearning of simple stimulus features. Our data also revealed methodological pitfalls, such as the possibility of occurring artifacts when combining different acquisition systems for central and peripheral psychophysiological measures

    The genetic contribution of the NO system at the glutamatergic post-synapse to schizophrenia : further evidence and meta-analysis

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    NO is a pleiotropic signaling molecule and has an important role in cognition and emotion. In the brain, NO is produced by neuronal nitric oxide synthase (NOS-I, encoded by NOS1) coupled to the NMDA receptor via PDZ. interactions; this protein-protein interaction is disrupted upon binding of NOS1 adapter protein (encoded by NOS1AP) to NOS-I. As both NOS1 and NOS1AP were associated with schizophrenia, we here investigated these genes in greater detail by genotyping new samples and conducting a meta-analysis of our own and published data. In doing so, we confirmed association of both genes with schizophrenia and found evidence for their interaction in increasing risk towards disease. Our strongest finding was the NOS1 promoter SNP rs41279104, yielding an odds ratio of 1.29 in the meta-analysis. As findings from heterologous cell systems have suggested that the risk allele decreases gene expression, we studied the effect of the variant on NOS1 expression in human post-mortem brain samples and found that the risk allele significantly decreases expression of NOS1 in the prefrontal cortex. Bioinformatic analyses suggest that this might be due the replacement of six transcription factor binding sites by two new binding sites as a consequence of proxy SNPs. Taken together, our data argue that genetic variance in NOS1 resulting in lower prefrontal brain expression of this gene contributes to schizophrenia liability, and that NOS1 interacts with NOS1AP in doing so. The NOS1-NOS1AP PDZ interface may thus well constitute a novel target for small molecules in at least some forms of schizophrenia. PostprintPeer reviewe

    Increased Risk of Hypertension Associated with Spondyloarthritis Disease Duration: Results from the ASAS-COMOSPA Study

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    Objective: Spondyloarthritis (SpA) is associated with a number of cardiovascular (CV) comorbidities. We examined the association of SpA disease duration and delay in diagnosis with CV-related conditions. Methods: Using data from the COMOSPA study, the associations between SpA disease duration and CV-related conditions were evaluated in univariable and multivariable logistic regression models. Each model examined 1 CV-related factor as dependent and “SpA disease duration” as a predictor, adjusted for relevant confounders. Results: Data from 3923 subjects (median SpA disease duration 5.1 yrs, interquartile range 1.3–11.8 yrs) were available for analysis. The main CV-related conditions were hypertension (HTN; 22.4%), ischemic heart disease (2.6%), stroke (1.3%), and diabetes mellitus (5.5%). HTN was associated with SpA disease duration in both univariable and multivariable analysis, with an OR of 1.129 (95% CI 1.072–1.189; p < 0.001) for each 5-year increase in SpA disease duration. Other factors associated with HTN were age, male sex, current body mass index, ever steroid therapy, and ever synthetic disease-modifying antirheumatic drug therapy, but not nonsteroidal antiinflammatory drugs (NSAID). In subgroup analysis, the strongest association of HTN and disease duration was seen in subjects with the axial-only SpA phenotype (OR 1.202, 95% CI 1.053–1.372) but not in those with peripheral-only SpA (OR 0.902, 95% CI 0.760–1.070). The other CV conditions were not associated with SpA disease duration. Conclusion: Duration of SpA disease in the ASAS-COMOSPA cohort is associated with higher odds of HTN, particularly in those with axial disease, but not with other CV-related conditions. The association with HTN does not appear to be related to NSAID exposure

    Data from the DESIR cohort

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    Funding: g Devenir des Spondyloarthropathies Indifférenciées Récentes (DESIR) is financially supported by an unrestricted grant from Pfizer. AS is supported by a doctoral grant from 'Fundação para a Ciência e Tecnologia' (SFRH/ BD/108246/2015). The DESIR study is conducted as a Programme Hospitalier de Recherche Clinique with Assistance Publique Hopitaux de Paris as the sponsor. The DESIR study is also under the umbrella of the French Society of Rheumatology, which financially supports the cohort. An unrestricted grant from Pfizer as been allocated for the first 10 years.Objective To study changes on MRI of the spine and sacroiliac joint (SIJ) in early axial spondyloarthritis (axSpA) over time. Methods In the Devenir des Spondyloarthropathies Indifférenciées Récentes cohort, MRI-spine and MRI-SIJ at baseline and 2 and 5 years were scored by central readers for bone marrow oedema (BME), fatty lesions, erosions, sclerosis, ankylosis and spinal bone spurs. The average mean number of lesions was reported or the agreement of ≥2 out of 3 readers for binary outcomes. Net progression was calculated by subtracting the patients that a € improved' from those that a € worsened' divided by the total number of patients. Results Over 5 years, in 155 patients with axSpA (mean age 33.5 (SD 8.9) years, symptom duration 1.4 (0.8) years, 63% human leucocyte antigen+, 14% modified New York+), BME on MRI-SIJ decreased by a mean Spondyloarthritis Research Consortium of Canada score of 1.4 (SD 6.5) (p=0.009). The largest BME decrease was observed in patients using biological disease-modifying antirheumatic drugs at 5 years. Spinal BME increased by 0.3 (4.6) (p=0.41). Fatty lesions and/or erosions on MRI-SIJ increased by a mean of 1.0 (SD 2.6) (p<0.001). Spinal fatty lesions and/or erosions increased by 0.2 (SD 0.5) (p<0.001). Compared with baseline, at 5 years, 7.3% less patients had BME on MRI-SIJ according to the Assessment of Spondyloarthritis International Society definition, while 6.6% more patients had ≥5 fatty lesions and/or erosions. At 5 years, 0.7% less patients had ≥5 spinal BME lesions and 0.7% less patients had ≥5 spinal fatty lesions. Conclusion Over 5 years, BME on MRI-SIJ decreased and spinal BME remained similar, but numerically, little progression of structural lesions on MRI of the SIJ and spine was seen.publishersversionpublishe
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