3,490 research outputs found

    Investigating the Relationship Between Escape and Gambling Behavior

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    Recent research suggests that there is a potentially strong relationship between gambling as a means of escape and the presence of pathological gambling. The goal of the present study was to establish whether there was a correlation between endorsing gambling as a means of escape and how participants played video poker in a laboratory setting. Forty eight participants completed several questionnaires and then played video poker. Results demonstrated that endorsement of gambling as a means of escape, as measured by the Gambling Functional Assessment (Dixon & Johnson, 2007), was significantly positively correlated with number of credits risked during video-poker play. It was not, however, correlated with number of hands played or number of errors made. The results therefore support the idea that escape and gambling have a unique relationship and suggest that this relationship may display itself as increased risk taking

    Evolution des recouvrements forestiers et de l'Occupation des sols entre 1964 et 2002 dans la haute vallée des Ait Bouguemez (Haut Atlas Central, Maroc). Impact des modes de gestion.

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    Les espaces forestiers montagnards méditerranéens sont souvent fortement dégradés. La cause principale est la surexploitation des ressources. Au cours de l'histoire, la rareté des ressources a probablement incité les hommes à mettre en place des formes de contrôle coutumières (ou « traditionnelles ») des espaces forestiers et pastoraux. Ces régimes perdurent dans le Haut Atlas marocain sous le nom d'agdal, terme qui désigne un territoire sylvopastoral collectif soumis à des mises en défens temporaires. Ce travail vise à évaluer l'impact de cette gestion coutumière sur les dynamiques des formations boisées dans une zone de montagne, la vallée des Ait Bouguemez, à travers une analyse diachronique basée sur la comparaison de documents anciens (photographies aériennes de 1964) avec des documents récents (image satellitaire Spot 5 à très haute résolution). La méthodologie adoptée repose sur la photointerprétation visuelle des documents précités en se basant sur une charte commune d'estimation du recouvrement arboré. Deux cartes de recouvrement ont été produites pour 1964 et 2002, dont le croisement a permis d'obtenir une carte de la dynamique des peuplements. Les résultats obtenus soulignent de fortes disparités dans les dynamiques forestières selon le statut agdal ou non-agdal de la forêt. La surface forestière a diminué de 21 % en 38 ans, et le recouvrement arboré moyen sur la zone forestière chute globalement de 20 % à 18 % pendant cette période. On observe un maintien du couvert boisé en zone agdal et sa forte dégradation hors agdal dans un contexte de forte croissance démographique

    Free-surface profiles, velocity and pressure distributions on a broad-crested weir: a physical study

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    Basic experiments were conducted on a large-size broad-crested weir with a rounded corner. Detailed free-surface, velocity, and pressure measurements were performed for a range of flow conditions. The results showed the rapid flow distribution at the upstream end of the weir and next to the weir brink at large flow rates. The flow properties above the crest were analyzed taking into account the nonuniform velocity and nonhydrostatic pressure distributions. Introducing some velocity and pressure correction coefficients, it is shown that critical flow conditions were achieved above the weir crest for 0.1 < x/L-crest < 1. The velocity measurements highlighted a developing boundary layer. The data differed from the smooth turbulent boundary layer theory, although the present results were consistent with earlier studies. On average, the boundary stress was approximately tau(o)/(rho x g x H-1) 0.0015-0.0025. DOI: 10.1061/(ASCE)IR.1943-4774.0000515. (C) 2012 American Society of Civil Engineers

    Hot Jupiters and Hot Spots: The Short- and Long-term Chromospheric Activity on Stars with Giant Planets

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    We monitored the chromospheric activity in the Ca II H & K lines of 13 solar-type stars (including the Sun); 8 of them over three years at the CFHT and 5 in a single run at the VLT. Ten of the 13 targets have close planetary companions. All of the stars observed at the CFHT show long-term (months to years) changes in H & K intensity levels. Four stars display short-term (days) cyclical activity. For two, HD 73256 and kappa^1 Ceti, the activity is likely associated with an active region rotating with the star, however, the flaring in excess of the rotational modulation may be associated with a hot jupiter. A planetary companion remains a possibility for kappa^1 Ceti. For the other two, HD 179949 and upsilon And, the cyclic variation is synchronized to the hot jupiter's orbit. For both stars this synchronicity with the orbit is clearly seen in two out of three epochs. The effect is only marginal in the third epoch at which the seasonal level of chromospheric activity had changed for both stars. Short-term chromospheric activity appears weakly dependent on the mean K-line reversal intensities for the sample of 13 stars. Also, a suggestive correlation exists between this activity and the M_p sin(i) of the star's hot jupiter. Because of their small separation (<= 0.1 AU), many of the hot jupiters lie within the Alfv\'en radius of their host stars which allows a direct magnetic interaction with the stellar surface. We discuss the conditions under which a planet's magnetic field might induce activity on the stellar surface and why no such effect was seen for the prime candidate, tau Boo. This work opens up the possibility of characterizing planet-star interactions, with implications for extrasolar planet magnetic fields and the energy contribution to stellar atmospheres.Comment: Accepted to the Astrophysical Journal; 39 pages including 17 figure

    GRB 221009A: A light dark matter burst or an extremely bright Inverse Compton component?

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    Gamma-ray bursts (GRBs) have been considered as potential very high-energy photon emitters due to the large amount of energy released as well as the strong magnetic fields involved in their jets. However, the detection of TeV photons is not expected from bursts beyond a redshift of z0.1z\gtrsim 0.1 due to their attenuation with the extragalactic background light (EBL). For these reasons, the recent observation of photons with energies of 18 and 251 TeV from GRB 221009A (z=0.151) last October 9th, 2022 has challenged what we know about the TeV-emission mechanisms and the extragalactic background. In order to explain the TeV observations, recent works exploring candidates of dark matter have started to appear. In this paper, we discuss the required conditions and limitations within the most plausible scenario, synchrotron-self Compton (SSC) radiation in the GRB afterglow, to interpret the one 18-TeV photon observation besides the EBL. To avoid the Klein-Nishina effect, we find an improbable value of the microphysical magnetic parameter below 10610^{-6} for a circumburst medium value >1cm3> 1{\rm cm^{-3}} (expected in the collapsar scenario). Therefore, we explore possible scenarios in terms of ALPs and dark photon mechanisms to interpret this highly-energetic photon and we discuss the implications in the GRB energetics. We find that the ALPs and dark photon scenarios can explain the 18 TeV photon but not the 251 TeV photon.Comment: 15 pages, 5 figures, 4 table

    Fear of non-employability and of economic crisis increaseworkplace harassment through lower organizational welfare orientation

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    There is a growing body of evidence suggesting that economic crisis is a preeminent stressor (i.e., economic stress) that may worsen working conditions and expose individuals to negative acts at work (i.e., workplace bullying). Following an occupational health perspective that considers contextual factors as risk factors for workplace bullying, this study aims to examine the mediation effects of organizational orientation to employee welfare in the economic stress-workplace bullying relationship. A cross-sectional study with the participation of 1004 Italian workers from several organizations was conducted. Our results indicate that economic stress (composed of two dimensions: fear of the economic crisis and perceived non-employability) is associated with workplace bullying through the total mediation of organizational orientation to employee welfare. These results have relevant implications for psychosocial risk assessment in turbulent times
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