Suchergebnisse

En Noviembre de 1995 la ciudad de Río Tercero fue afectada por las explosiones de los polvorines de la Fábrica Militar; esta situación se considera un desastre, puesto que causó daños de gran magnitud, superando los recursos con los que contaba la comunidad. Este artículo tiene el propósito de brindar respuestas a interrogantes acerca de las secuelas emocionales que dejaron las explosiones, relacionándolas a los efectos que provoca la continuidad de riesgo tecnológico. A este fin se describirán las consecuencias psicológicas encontradas a través de investigaciones realizadas a lo largo de 16 años en la población afectada, con respecto a sintomatología mental y sentimiento de vulnerabilidad. Sintomatología Mental: comparando las medias de estudios epidemiológicos llevados a cabo en Río Tercero, se observó que la media del año 2011 (28,1), tuvo un descenso muy leve en relación al año 2001 (29,8). También disminuyó la distribución de los sujetos en los niveles de alta y muy alta sintomatología mental consideradas conjuntamente (2001, 39,3 % - 2011, 25,2%). Una importante proporción de la población aún se encontraba por encima de la media de sintomatología mental luego de 16 años de la vivencia de las explosiones. Sentimiento de Vulnerabilidad: la media del año 2001 fue de 8,4 y en el 2011 de 8,5, no evidenciándose diferencias estadísticamente significativas. Los datos obtenidos indican que en el año 2011 se mantuvo la misma tendencia que en el año 2001: a mayor sentimiento de vulnerabilidad, mayor sintomatología mental.

Whole-body vibration (WBV) training programs were reported to improve knee extensor muscle (KE) strength in healthy participants. Unfortunately, the underlying mechanisms of these strength gains remain unresolved. In addition, WBV training was shown to increase the time-to-exhaustion of a static submaximal endurance task. However, the effects of WBV training on neuromuscular fatigue (i.e., a decrease of the maximal voluntary isometric contraction; MVIC) induced by an endurance task is unknown. We, therefore, investigated the influence of WBV training on (i) KE MVIC and neuromuscular function, (ii) the time-to-exhaustion of the KE associated with a submaximal isometric fatiguing exercise, and (iii) KE neuromuscular fatigue and its etiology. Eighteen physically active males were assigned to a WBV group (n = 10) or a sham training group (SHAM; n = 8). The MVIC of the KE, voluntary activation, and electrically evoked responses of the KE were assessed (i) before and after a fatiguing exercise (i.e., submaximal isometric contraction) performed until failure, and (ii) before (PRE) and after a 6-week training (POST) period. At POST, the WBV training increased the KE MVIC (+12%, p = 0.001) and voluntary activation (+6%, p < 0.05) regardless of the fatiguing exercise. The time-to-exhaustion was also lengthened at POST in the WBV group (+34%, p < 0.001). Finally, the relative percentage of MVIC decrease after fatiguing exercises diminished in the WBV group between PRE and POST (−14% vs. −6%, respectively, p < 0.001). Significant neural adaptation enhancements account for the trend in KE strength improvements observed after the WBV training program. In addition, the WBV training was effective at increasing the time-to-exhaustion and attenuating neuromuscular fatigue.

Comme dans la plupart des régions, les zones arides ont bénéficié de plusieurs vagues d'aménagements hydroagricoles durant la seconde moitié du XX e siècle pour ralentir, stocker et rendre accessibles des écoulements sporadiques et violents peu utilisables par des ouvrages au fil de l'eau. Cette succession d'aménagements superposés est souvent mal valorisée comme le montrent divers bilans réalisés dans des bassins du Centre tunisien et du Nord Mexique où les retenues collinaires favorisent, avant tout, les pertes évaporatoires. Sur la base de ces constats, les gouvernements ont cherché à améliorer la gestion technique des ouvrages en favorisant les transferts d'eau vers les réservoirs souterrains et cherchent à mobiliser les ressources en eau non conventionnelles avec quelques succès, mais seulement dans des situations spécifiques en raison de leurs coûts élevés (désalinisation), d'une difficile acceptation (réutilisation des eaux usées) ou de leur volume peu important (eau atmosphérique). Toutes ces initiatives n'ont pas arrêté la surexploitation des nappes phréatiques, et peu à peu se mettent en place plusieurs initiatives pour diminuer la demande en eau tout en augmentant la production alimentaire. Cette nouvelle politique finance l'installation des techniques d'irrigation économes (aspersion, goutte-à-goutte, polymères gonflants, conduites verticales, etc.) pour remplacer l'irrigation gravitaire majoritairement utilisée. Après quelques années, il faut bien reconnaître que l'impact de ces nouvelles techniques est moins important que prévu soit à cause d'une utilisation inadéquate, soit par le fait de nouveaux comportements qu'elles ont suscités. Actuellement, les pouvoirs publics testent des outils complémentaires économiques et réglementaires pour rendre plus efficaces ces changements techniques.

Coarse particulate matter (PM10) concentrations and chemical composition were monitored from 2014 to 2017 at three sampling sites in the Metropolitan Region of Rio de Janeiro, namely Botafogo, Gávea, and Gericinó. All sites are located close to the 2016 Olympic Game arenas. The average annual PM10 concentrations were above the limits recommended by the World Health Organization (WHO) at all sampling sites. Of all the analyzed water-soluble ions, the highest concentrations were obtained for NO3-, SO42-, Cl- and Na+. Sulfate displayed a higher anthropic contribution (ca. 70%). Iron and copper were present in all samples, originated from soil resuspension and traffic (fuels and brakes, among others). Overall, civil works to restructure the city and the construction of the Olympic Game arenas increased PM10 and some of its constituent levels prior to 2016. After the Olympic Games, PM10 concentrations have decreased, due to governmental policies regarding traffic planning and civil work finalization.

AbstractThe exposure to airborne particulate matter (PM) and its constituents is an important factor to be considered when evaluating their potential health risk. Transition metals found in PM are known to contribute significantly to the exacerbation of respiratory ailments. Exposure to these constituents results in the induction of oxidative stress in the bronchial epithelium, thus promoting the secretion of inflammatory mediators. Therefore, it is important to know the contributions of PM2.5 constituents to further investigate their relationship with toxic responses and associated health risks. PM2.5 samples from three rural (Humacao, Guayama, and Guayanilla) and two urban (more populated) sites (Bayamón and Ponce) from Puerto Rico were analyzed for various inorganic constituents. A total of 59 trace elements were analyzed, of which eight were considered with the greatest toxic potential. The highest annual average concentration of PM2.5 was reported at the urban site of Ponce (5.82 ± 1.40 μg m−3), while Bayamón's average concentration was not as high (4.69 ± 1.30 μg m−3) compared to concentrations at the rural sites Humacao, Guayama, and Guayanilla (4.33 ± 1.20 μg m−3, 4.93 ± 1.50 μg m−3, and 4.88 ± 1.20 μg m−3 respectively. The concentration at the Ponce site exhibited the highest summer value (7.57 μg m−3) compared to that of all the rural sites (~ 6.40 μg m−3). The lowest summer PM2.5 values were obtained at the Humacao site with an average of 5.76 μg m−3. Average Cu and Zn concentrations were 3- and 2-fold higher at the urban sites (0.68 ng m−3 and 6.74 ng m−3 respectively) compared to the rural sites (0.17 ng m−3 and 4.11 ng m−3). Relative toxicity of inorganic PM extract indicates Bayamón (urban) and Guayama with similar low LC50 followed by Humacao, Guayanilla, and finally Ponce (urban) with the highest LC50. Of the eight potential toxic metals considered, only Fe was found to be higher at the rural sites. To our understanding, there are different sources of emission for these metals which potentially indicate main anthropogenic sources, together with the trade winds adding periodically volcanic and African Dust Storm particulates that affect Puerto Rico. These results are the first of their kind to be reported in Puerto Rico.