544 research outputs found

    Optimizing training adaptations by manipulating glycogen

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    For decades, glycogen has been recognized as a storage form of glucose within the liver and muscles. Only recently has a greater role for glycogen as a regulator of metabolic signalling been suggested. Glycogen either directly or indirectly regulates a number of signalling proteins, including the adenosine-5\u27-phosphate- (AMP-) activated protein kinase (AMPK) and p38 mitogen-activated protein kinase (MAPK). AMPK and p38 MAPK play a significant role in controlling the expression and activity of the peroxisome proliferator activated receptor &gamma; coactivators (PGCs), respectively. The PGCs can directly increase muscle mitochondrial mass and endurance exercise performance. As low muscle glycogen is generally associated with greater activation of these pathways, the concept of training with low glycogen to maximize the physiological adaptations to endurance exercise is gaining acceptance in the scientific community. In this review, we evaluate the scientific basis for this philosophy and propose some practical applications of this philosophy for the general population as well as elite endurance athletes.<br /

    Active oceanic spreading in the northern north Fiji basin : results of the NOFI cruise of R/V l'Atalante (Newstarmer project)

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    The South Pandora and the Tripartite Ridges are active spreading centers located in the northern part of the North Fiji Basin. These spreading centers were surveyed over a distance of 750 km during the NOFI cruise of R/V L'Atalante (August-September 1994) which was conducted in the frame of the french-japanese Newstarmer cooperation project. SIMRAD EM12-dual full coverage swath bathymetric and imagery data as well as airgun 6-channel seismic, magnetics and gravity profiles were recorded along an off-axis from 170°40'E to 178°E. Dredging and piston coring were also performed along and off-axis. The axial domain of the South Pandora Ridge is divided into 5 first-order segments characterized by contrasted morphologies. The average width of the active domain is 20 km and corresponds either to bathymetric highs or to deep elongated grabens. The bathymetric highs are volcanic constructions, locally faulted and rifted, which can obstruct totally the axial valley. The grabens show the typical morphology of slow spreading axes, with two steep walls flanking a deep axial valley. Elongated lateral ridges may be present on both sides of the grabens. Numerous volcanoes, up to several kilometers in diameter, occur on both flanks of the South Pandora Ridge. The Tripartite Ridge consists of three main segments showing a sigmoid shape. Major changes in the direction of the active zones are observed at the segment discontinuities. These discontinuities show various geometrical patterns which suggest complex transform relay zones. Preliminary analysis of seismic reflection profiles suggest that the Tripartite Ridge is a very young feature which propagates into an older oceanic domain characterized by a significant sedimentary cover. By contrast, a very thin to absent sedimentary cover is observed about 100 km on both flanks of the South Pandora Ridge active axis. The magnetic anomaly profiles give evidence of long and continuous lineations, parallel to the South Pandora Ridge spreading axis. (Résumé d'auteur

    Low-Frequency Heroin Injection among Out-of-Treatment, Street-Recruited Injection Drug Users

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    In this paper, we explore the understudied phenomenon of "low-frequency" heroin injection in a sample of street-recruited heroin injectors not in drug treatment. We conducted a cross-sectional study of 2,410 active injection drug users (IDUs) recruited in San Francisco, California from 2000 to 2005. We compare the sociodemographic characteristics and injection risk behaviors of low-frequency heroin injectors (low-FHI; one to 10 self-reported heroin injections in the past 30 days) to high-frequency heroin injectors (high-FHI; 30 or more self-reported heroin injections in the past 30 days). Fifteen percent of the sample met criteria for low-FHI. African American race, men who have sex with men (MSM) behavior, and injection and noninjection methamphetamine use were independently associated with low-FHI. Compared to high-FHI, low-FHI were less likely to report syringe sharing and nonfatal heroin overdose. A small but significant proportion of heroin injectors inject heroin 10 or less times per month. Additional research is needed to qualitatively examine low-frequency heroin injection and its relationship to drug use trajectories

    Making drug harms: Punishments for drugs offenders who pose risks to children

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    Images of children are routinely used in discourses on drugs, offering a compelling rationale for adopting particular policy positions or legislative reforms. However, the importance of childhood to the constitution of drug harms, and the punishment and subjectification of drug users and offenders, have rarely been the subject of enquiry, whether within drug and alcohol studies, criminology or legal studies. Scholarship on criminal sentencing in England and Wales is also relatively sparse, and has been dominated by analyses of the ‘legal-rational’ logic of particular provisions or reforms. This paper, which relies on the premise that drugs and their effects are constituted through discourse, and are thus contingent, variable and unstable, identifies the ‘collateral realities’ (Law, 2011) that are enacted during legislative and judicial attempts to stabilize the harms caused by drugs to children and communities

    The Moral Economy of Heroin in ‘Austerity Britain’

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    This article presents the findings of an ethnographic exploration of heroin use in a disadvantaged area of the United Kingdom. Drawing on developments in continental philosophy as well as debates around the nature of social exclusion in the late-modern west, the core claim made here is that the cultural systems of exchange and mutual support which have come to underpin heroin use in this locale—that, taken together, form a ‘moral economy of heroin’—need to be understood as an exercise in reconstituting a meaningful social realm by, and specifically for, this highly marginalised group. The implications of this claim are discussed as they pertain to the fields of drug policy, addiction treatment, and critical criminological understandings of disenfranchised groups

    The Asymmetry Coefficient for Interstellar Scintillation of Extragalactic Radio Sources

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    Comparing the asymmetry coefficients and scintillation indices for observed time variations of the intensity of the radiation of extragalactic sources and the predictions of theoretical models is a good test of the nature of the observed variations. Such comparisons can be used to determine whether flux-density variations are due to scintillation in the interstellar medium or are intrinsic to the source. In the former case, they can be used to estimate the fraction of the total flux contributed by the compact component (core) whose flux-density variations are brought about by inhomogeneities in the interstellar plasma. Results for the radio sources PKS 0405-385, B0917+624, PKS 1257-336, and J1819+3845 demonstrate that the scintillating component in these objects makes up from 50% to 100% of the total flux, and that the intrinsic angular sizes of the sources at 5 GHz is 10-40 microarcseconds. The characteristics of the medium giving rise to the scintillations are presented

    VOLUMEN 15, NÚMERO 29 (1981-1982)

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    USO DEL COMPUTADOR EN EL ANÁLISIS SEDIMENTOLÓGICO Y DE MIGRACIÓN DE FLUIDOS Y SU APLICACIÓN EN EL NOROCCIDENTE COLOMBIANO. Castro, A. E.; Molina, G. J.UN MODELO ESTRUCTURAL PARA EL VALLE DEL CAUCA Y SUS IMPLICACIONES HIDROGEOLÓGICAS Y MINERAS. Padilla, L. E.TECTÓNICA DE SOBRECORRIMIENTO Y SUS IMPLICACIONES ESTRUCTURALES EN EL ÁREA PAMPLONA - CORDILLERA ORIENTAL DE COLOMBIA. Boinet, T.; Bourgois, J.; Mendoza F. HGEOLOGÍA DE LAS LATERITAS NIQUELÍFERAS DE CERRO MATOSO S. A. Mejía, V. M.; Durango, J. R.COMPLEJO OFIOLÍTICO EN LA CUENCA DEL RÍO GUAPI. Ortega Montero, C.DETERMINACIÓN DE RESERVAS DE DEPÓSITOS MINERALES. Hernández Garay, H.CARACTERIZACIÓN, RANGO Y CLASIFICACIÓN DE CARBONES. Ramírez Castro, P

    VOLUMEN 15, NÚMERO 29 (1981-1982)

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    USO DEL COMPUTADOR EN EL ANÁLISIS SEDIMENTOLÓGICO Y DE MIGRACIÓN DE FLUIDOS Y SU APLICACIÓN EN EL NOROCCIDENTE COLOMBIANO. Castro, A. E.; Molina, G. J.UN MODELO ESTRUCTURAL PARA EL VALLE DEL CAUCA Y SUS IMPLICACIONES HIDROGEOLÓGICAS Y MINERAS. Padilla, L. E.TECTÓNICA DE SOBRECORRIMIENTO Y SUS IMPLICACIONES ESTRUCTURALES EN EL ÁREA PAMPLONA - CORDILLERA ORIENTAL DE COLOMBIA. Boinet, T.; Bourgois, J.; Mendoza F. HGEOLOGÍA DE LAS LATERITAS NIQUELÍFERAS DE CERRO MATOSO S. A. Mejía, V. M.; Durango, J. R.COMPLEJO OFIOLÍTICO EN LA CUENCA DEL RÍO GUAPI. Ortega Montero, C.DETERMINACIÓN DE RESERVAS DE DEPÓSITOS MINERALES. Hernández Garay, H.CARACTERIZACIÓN, RANGO Y CLASIFICACIÓN DE CARBONES. Ramírez Castro, P
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