455 research outputs found
The Chuacús Metamorphic Complex, central Guatemala : geochronological and geochemical constraints on its Paleozoic - Mesozoic evolution
The Chuacús Metamorphic Complex is located in Central Guatemala, between the Polochic and Motagua fault zones. It is made up of complexly intercalated, mafic and felsic high-grade gneisses, amphibolites, pelitic and quartzofeldsphatic metasediments and subordinate marbles. Mafic dikes and lenses metamorphosed to amphibolite and eclogite facies are tholeiitic and similar to mid-ocean ridge basalts. In contrast, metamorphosed intrusives (gabbro, diorite and granite) are calc-alkaline and have the geochemical signature of arc magmas. Laser Ablation Inductively Coupled Plasma Mass Spectrometry U-Pb zircon geochronology allows the recognition of three episodes of metamorphism. The first eclogite facies metamorphism (M1) is bracketed between Ordovician magmatism in the northern Chuacús Metamorphic Complex and the neighboring Rabinal granitic suite; the second corresponds to an Upper Triassic period of arc magmatism and migmatization (M2); the third high-grade metamorphic event (M3) occurred during the Late Cretaceous. The tectonic evolution of the Chuacús Metamorphic Complex began during the Early Paleozoic as a basin in the Rheic Ocean that received detrital material from the Maya Block, Acatlán and southeastern México. The Chuacús Metamorphic Complex evolved to an active margin that subducted to HP conditions during the Mid- Late Paleozoic, and then was exhumed and involved in two tectonothermal events during the Upper Triassic and Late Cretaceous. The Chuacús Metamorphic Complex was accreted to the southern Maya Block during the Late Cretaceous, as a result of the convergent tectonics between the latter and either the Greater Antillean arc or the Chortís Block
Irrigation efficiency and water-policy implications for river basin resilience
Rising demand for food, fiber, and biofuels drives
expanding irrigation withdrawals from surface water and groundwater. Irrigation
efficiency and water savings have become watchwords in response to
climate-induced hydrological variability, increasing freshwater demand for
other uses including ecosystem water needs, and low economic productivity of
irrigation compared to most other uses. We identify three classes of
unintended consequences, presented here as paradoxes. Ever-tighter cycling
of water has been shown to increase resource use, an example of the
<i>efficiency paradox</i>. In the absence of effective policy to
constrain irrigated-area expansion using "saved water", efficiency can
aggravate scarcity, deteriorate resource quality, and impair river basin
resilience through loss of flexibility and redundancy. Water scarcity and
salinity effects in the lower reaches of basins (symptomatic of the
<i>scale paradox</i>) may partly be offset over the short-term through
groundwater pumping or increasing surface water storage capacity. However,
declining ecological flows and increasing salinity have important
implications for riparian and estuarine ecosystems and for non-irrigation
human uses of water including urban supply and energy generation, examples
of the <i>sectoral paradox</i>. This paper briefly considers three
regional contexts with broadly similar climatic and water-resource
conditions – central Chile, southwestern US, and south-central
Spain – where irrigation efficiency directly influences basin resilience.
The comparison leads to more generic insights on water policy in relation to
irrigation efficiency and emerging or overdue needs for environmental protection
Effects of the presence of cellulose and curaua fibers on the thermal and mechanical properties of eco-composites based on cellulose acetate
FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOLos materiales eco-compósitos han obtenido el interés de la academia, debido a sus características amigables al medio ambiente. En este trabajo, se prepararon dos grupos de eco-compósitos con matriz de acetato de celulosa, reforzados con fibras de celulos172533546FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2010/02098-02010/17804-7Los autores agradecen el financiamiento de los proyectos CONACYT 251504 y 264110. Además,se agradece a EMBRAPA por donar las fibras y aFAPESP (2010/02098-0 y 2010/17804-7
Protective Effect of Melatonin Against Mitomycin C-Induced Genotoxic Damage in Peripheral Blood of Rats
Mitomycin C (MMC) generates free radicals when metabolized. We investigated the effect of melatonin against MMC-induced genotoxicity in polychromatic erythrocytes and MMC-induced lipid peroxidation in brain and liver homogenates. Rats (N = 36) were classified into 4 groups: control, melatonin, MMC, and MMC + melatonin. Melatonin and MMC doses of
10 mg/kg and 2 mg/kg, respectively, were injected intraperitoneally. Peripheral blood samples were collected at 0, 24, 48, 72, and 96 hours posttreatment and homogenates were obtained at 96 hours posttreatment. The number of micronucleated polychromatic erythrocytes (MN-PCE) per 1000 PCE was used as a genotoxic marker. Malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA) levels were used as an index of lipid peroxidation. The MMC group showed a significant increase in MN-PCE at 24, 48, 72, and 96 hours that was significantly reduced with melatonin begin coadministrated. No significant differences were found in lipid peroxidation. Our results indicate that MMC-induced genotoxicity can be reduced by melatonin
Methodology to improve the model of series inductance in CMOS integrated inductors
This paper presents a systematic optimization methodology to achieve an accurate estimation of series inductance of inductors implemented in standard CMOS technologies. Proposed method is based on an optimization procedure which aims to obtain adjustment factors associated to main physical inductor characteristics, allowing to estimate more accurate series inductance values that can be used in design stage. Experimental measurements of diverse square inductor geometries are shown and compared with previous approaches in order to demonstrate and validate presented approach.National Council of Science and Technology of México (CONACYT) TEC2013-45638-C3-3-RSpanish Ministry of Economy and Competitiveness TEC2013-45638-C3-3-REuropean Regional Development Fund TEC2013-45638-C3-3-RConsejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía P12-TIC-148
Comportamiento del material vegetal de cebolla Fuentes de Ebro. Inicio de un programa de mejora genética
Cebolla de FuentesPublishe
Expression of the dopaminergic D1 and D2 receptors in the anterior cingulate cortex in a model of neuropathic pain
<p>Abstract</p> <p>Background</p> <p>The anterior cingulate cortex (ACC) has been related to the affective component of pain. Dopaminergic mesocortical circuits, including the ACC, are able to inhibit neuropathic nociception measured as autotomy behaviour. We determined the changes in dopamine D1 and D2 (D1R and D2R) receptor expression in the ACC (cg1 and cg2) in an animal model of neuropathic pain. The neuropathic group had noxious heat applied in the right hind paw followed 30 min. later by right sciatic denervation. Autotomy score (AS) was recorded for eight days and subsequently classified in low, medium and high AS groups. The control consisted of naïve animals.</p> <p>A semiquantitative RT-PCR procedure was done to determine mRNA levels for D1R and D2R in cg1 and cg2, and protein levels were measured by Western Blot.</p> <p>Results</p> <p>The results of D1R mRNA in cg1 showed a decrease in all groups. D2R mRNA levels in cg1 decreased in low AS and increased in medium and high AS. Regarding D1R in cg2, there was an increase in all groups. D2R expression levels in cg2 decreased in all groups. In cg1, the D2R mRNA correlated positively with autotomy behaviour. Protein levels of D2R in cg1 increased in all groups but to a higher degree in low AS. In cg2 D2R protein only decreased discretely. D1R protein was not found in either ACC region.</p> <p>Conclusions</p> <p>This is the first evidence of an increase of inhibitory dopaminergic receptor (D2R) mRNA and protein in cg1 in correlation with nociceptive behaviour in a neuropathic model of pain in the rat.</p
Influencia de la variabilidad en la virulencia de diferentes aislados de Toxoplasma gondii sobre las lesiones de encéfalos fetales ovinos
Trabajo presentado a la: XXXII Reunión de la Sociedad Española de Anatomía Patológica Veterinaria (SEAPV). 1 octubre. Congreso virtual.Peer reviewe
Craving and Anxiety Responses as Indicators of the Efficacy of Virtual Reality-Cue Exposure Therapy in Patients Diagnosed with Alcohol use Disorder
Introduction: Virtual Reality (VR) technology has shown promising results as an assessment and treatment instrument in substance use disorders, particularly in attempts to reduce craving. A common application of the VR technology in treatment is based on cue-exposure therapy (CET). Following from previous results, the present case series is part of a larger project aiming to test the efficacy of the Virtual Reality-Cue Exposure Therapy (VR-CET) versus Cognitive-Behavioral Therapy (CBT). Method: Eight patients between ages 40 and 55 (Mage = 49, SD = 5.54) from the Addictive Behaviors Unit at the Hospital Clinic of Barcelona participated in this study after providing written informed consent. Patients were randomly assigned to the VR-CET group (three patients) or the CBT group (five patients). The protocol of the clinical trial consisted of a pre-treatment session (the initial assessment session), six sessions of CBT or VR-CET, and a post-treatment session (post-assessment session). The VR-CET sessions consisted of exposure to alcohol-related cues and environments aiming to reduce anxiety and craving responses to alcohol-related stimuli. The CBT sessions consisted of classical standardized therapy for the treatment of addictions, as previously applied in other clinical trials. In the pre- and post-treatment sessions, patients completed several measures of alcohol craving and anxiety and visual analog scales (VAS) during VR exposure. Results: Our data indicated a significant reduction in both groups in all scores of craving and anxiety responses, as assessed by the different instruments. In addition, the VR-CET group obtained lower scores on anxiety and craving responses than the CBT group. Conclusions: In this ongoing project, the first phase of the clinical trial showed significant improvements in terms of craving and anxiety reduction in both groups, emphasizing that VR-CET can be as efficient as CBT. In addition, patients in the VR-CET group obtained slightly better scores than patients in the CBT group, suggesting the clinical potential of the VR technology in the treatment of substance use disorders. We propose that VR-based CET can be a useful complement to existing treatment methods for AUD patients
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