60 research outputs found

    Cascading effects associated with climate-change-induced conifer mortality in mountain temperate forests result in hot-spots of soil CO 2 emissions

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    Climate change-induced tree mortality is occurring worldwide, at increasingly larger scales and with increasing frequency. How climate change-induced tree mortality could affect the ecology and carbon (C) sink capacity of soils remains unknown. This study investigated regional-scale drought-induced tree mortality, based on events that occurred after a very dry year (2012) in the Carpathians mountain range (Romania), which caused mortality in three common conifer species: Scots pine, Black pine, and Silver fir. This resulted in hot-spots of biogenic soil CO 2 emissions (soil respiration; Rs). Four to five years after the main mortality event, Rs-related soil CO 2 emissions under dead trees were, on average, 21% (ranging from 18 to 35%) higher than CO 2 emissions under living trees. Total (Rs) and heterotrophic (R H )-related soil CO 2 emissions were strongly related to alterations in the soil environment following tree mortality (e.g. changes in quantity and quality of soil organic matter, microclimate, pH or fine root demography). Moreover, the massive mortality event of 2012 resulted in greater presence of successional vegetation (broadleaf seedlings, shrubland and grasses), which may control the environmental factors that either directly or indirectly affected biotic soil fluxes (Rs and R H ). Besides the well-known direct effects of climate change on soil CO 2 emissions, the cascading effects triggered by climate change-induced tree mortality could also exert a strong indirect impact on soil CO 2 emissions. Overall, climate change-induced tree mortality alters the magnitude of environmental controls on Rs and hence determines how the ecosystem C budget responds to climate change. © 2019 Elsevier LtdThis work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) with the projects VERONICA ( CGL2013-42271-P ) and the project IBERYCA ( CGL2017-84723-P ), and by the Romanian Ministry of Education and Scientific Research through UEFISCDI with the projects TREEMORIS ( PN-II-RU-TE-2014-4-0791 ), NATIvE ( PN-III-P1-1.1-PD-2016-0583 ), and BIOCARB ( PN-III-P1-1.1-TE-2016-1508 ). This research was also supported by the Basque Government through the BERC 2018-2021 program, and by the Spanish Ministry of Economy and Competitiveness (MINECO) through the BC3 María de Maeztu excellence accreditation ( MDM-2017-0714 ). I.C. Petritan was partially funded by the H2020/ERA-NET/ERA-GAS (Project 82/2017, Mobilizing and monitoring climate positive efforts in forests and forestry, FORCLIMIT ). Many thanks to Cosmin Zgremtia, Ionela Medrea, Andrei Apafaian, Raluca Enescu and Marta Ramos for their valuable help during field campaigns and laboratory work

    Characterization of source rocks and groundwater radioactivity at the Chihuahua valley

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    As part of a scientific research project about alpha radioactivity in groundwater for human consumption at the Chihuahua City, the charac-terization of rock sources of radioactivity around de Chihuahua valley was developed. The radioactivity of groundwater and sediments wasdetermined, too. The radioactivity of uranium- and thorium- series isotopes contained in rocks was obtained by high resolution gamma-rayspectroscopy. Some representative values are 50 Bq/kg for the mean value of Bi-214 activity, and 121.5 Bq/kg for the highest value at Westof the city. The activity of sediments, extracted during wells perforation, was determined using a NaI(Tl) detector. A non-reported beforeuranium ore was localized at the San Marcos range formation. Its outcrops are inside the Chihuahua-Sacramento valley basin and its activ-ity characterization was performed. Unusually high specific uranium activities, determined by alpha spectrometry, were obtained in water,plants, sediments and fish extracted at locations close to outcrops of uranium minerals. The activity of water of the San Marcos dam reached7.7 Bq/L. The activity of fish, trapped at San Marcos dam, is 0.99 Bq/kg. Conclusions about the contamination of groundwater at North ofChihuahua City were obtained.Como parte de un proyecto cient ́ıfico sobre actividad alfa en agua subterr ́anea de consumo humano en la ciudad de Chihuahua, se hadesarrollado la caracterizaci ́on de las rocas fuentes de la radiactividad en el valle de Chihuahua. Se determin ́o tambi ́en la actividad de muestrasde agua subterr ́anea y de sedimentos. La actividad de los is ́otopos de las series radiactivas en las rocas se obtuvo usando espectroscop ́ıagamma de alta resoluci ́on. Algunos valores representativos son 50 Bq/kg para el valor medio de la actividad del Bi-214 y 121.5 Bq/kg para elvalor m ́as alto al oeste de la ciudad. La actividad de los sedimentos extra ́ıdos durante la perforaci ́on de pozos para agua potable, se determin ́ousando un detector de NaI(Tl). En la formaci ́on monta ̃nosa de San Marcos se localiz ́o un dep ́osito de uranio no publicado. Sus afloramientosse encuentran dentro de la cuenca del valle Chihuahua-Sacramento y se realiz ́o la caracterizaci ́on de su radiactividad. Se determinaronactividades por espectrometr ́ıa alfa de agua, plantas, sedimentos y peces extra ́ıdos en emplazamientos cercanos a los afloramientos deminerales de uranio. La actividad del agua en la presa de san Marcos lleg ́o a 7.7 Bq/L. La actividad de pescados de la misma presa alcanza0.99 Bq/kg. Se obtuvieron conclusiones sobre la contaminaci ́on del agua subterr ́anea al norte de la ciudad de Chihuahua

    Prevalence, risk factors, and identification of Salmonella spp. in stray dogs of northwest Mexico

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    Salmonellosis has a worldwide relevance in aspects associated with public health, as only in 2009 were reported 93.8 million cases in humans. The objective of the study was to establish the prevalence, risk factors and bacteriological and molecular identification of Salmonella spp in stray dogs in urban, rural and coastal areas of Mexicali, a city in northwest Mexico. From May 2014 to February 2015, 385 dogs were tested. Sampling was performed by rectal swab and conventional bacteriological techniques were applied, for later implementation of the API 20E system and molecular identification by polymerase chain reaction (PCR). The data were analysed statistically by means of descriptive statistics and multiple logistic regression modelling. A prevalence of 6.27% was obtained in the dogs examined, the samples obtained were characterised to subspecies (Salmonella enterica subspecies enterica and Salmonella enterica subspecie arizonae). The geographical region with the highest prevalence in the study was the coast (10%), followed by the rural area (8.57%) and the urban area (5.8%), however, no significant statistical differences were detected. There was significant difference in the prevalence by age of dogs under one year (P<0.05). The identification of Salmonella in dogs from northwest Mexico could correspond to serovars of zoonotic importance indicating a potential risk for the population

    Small-Bowel Obstruction Secondary to Ileal Trichobezoar in a Patient with Rapunzel Syndrome

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    Bezoars are conglomerations of undigested foreign material retained in the gastrointestinal tract. Trichobezoar is a compact conglomeration of swallowed hair and constitutes less than 6% of all bezoars. Their most frequent location is in the stomach but they may extend through the pylorus into the small bowel. This condition is known as Rapunzel syndrome. Many patients may remain asymptomatic or present a mild form of the disease characterized by abdominal pain, early satiety, nausea, and vomiting. Complications may manifest as gastric outlet obstruction or bleeding, and intestinal obstruction. A 15-year-old female patient presented with clinical findings of intestinal obstruction. The patient suffered from depressive and anxiety disorders and trichotillomania, although trichophagy could not be assured. Alopecia circumscripta and irregular hair length on the scalp were identified. A computed tomography (CT) scan showed two images highly suggestive of trichobezoars, one in the stomach and the second one causing obstruction at the ileocecal valve. At laparotomy, both a mobile gastric trichobezoar with a tail extending to the duodenum and a trichobezoar causing obstruction at the ileocecal valve were removed. The postoperative course was uneventful. The passage of a detached trichobezoar fragment in a patient with Rapunzel syndrome may cause intestinal obstruction. CT is the preferred image modality for the evaluation of suspected trichobezoars in order to characterize their size and locations, the presence and level of obstruction, and complications such as ischemia or perforation. A case of small-bowel obstruction secondary to ileal trichobezoar in a patient with Rapunzel syndrome is herein reported

    HE-LHC: The High-Energy Large Hadron Collider – Future Circular Collider Conceptual Design Report Volume 4

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    In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries

    FCC-ee: The Lepton Collider – Future Circular Collider Conceptual Design Report Volume 2

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    Volviéndonos mejores: necesidad de acción inmediata ante el reto de la obesidad. Una postura de profesionales de la salud.

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    La creciente epidemia de obesidad ha sido uno de los retos mĂĄs importantes de salud pĂșblica en MĂ©xico durante los Ășltimos años. Con apoyo de la FederaciĂłn Mundial de Obesidad, en 2021 formamos un grupo de profesionales para identificar y resumir las acciones prioritarias en las que puede enfocarse nuestro paĂ­s para hacer frente a esta epidemia. Al proceso de desarrollo y discusiĂłn de este grupo se sumaron mĂĄs de 1 000 profesionales de la salud para retomar recomendaciones de documentos y guĂ­as de alto nivel previamente publicados. En conmemoraciĂłn del DĂ­a Mundial de la Obesidad, en este 2022 se presenta esta postura como insumo para el desarrollo de acciones en el ĂĄmbito profesional y de los diferentes sectores, en la que se incluyen 10 recomendaciones de acciĂłn, desde la perspectiva poblacional hasta la atenciĂłn individualizada, y se enfatiza en la importancia de la participaciĂłn social, de las intervenciones integrales con visiĂłn centrada en la persona y de la sostenibilidad planetaria, ademĂĄs de mejorar la educaciĂłn y las campañas de difusiĂłn, propiciar un ambiente promotor de entornos activos y blindar de conflictos de interĂ©s los esfuerzos de prevenciĂłn y control. La postura hace un llamado para abordar la obesidad de manera seria, con base en la evidencia cientĂ­fica, oportuna e integral, con enfoque de curso de vida, de forma Ă©tica y sensible, y sin perpetuar las barreras del estigma de peso en la sociedad

    On the sensitivity of the HAWC observatory to gamma-ray bursts

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    We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles
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