Interaction of surface and subsurface hydrological processes in the Lower Virgin Valley

The Lower Virgin Valley\u27s water resources are increasingly vital to Southern Nevada. This study sought to answer three questions of relevance to local water managers: (1) What is the spatial distribution of recharge to groundwater in a basin divided between three states? (2) How do streamflow and evapotranspiration affect the water table in the Virgin River floodplain? (3) How would long-term pumping of the floodplain aquifer affect the water table and the dependent phreatophytic vegetation? A Maxey-Eakin analysis showed that nearly 48 percent of rainfall-induced recharge to groundwater occurs in Nevada while nearly 49 percent occurs in Utah and just over three percent occurs in Arizona. A MODLFOW-2000 model of the floodplain aquifer demonstrated the link between seasonal water table fluctuation and variation in streamflow and evapotranspiration rates. Finally, simulation of a production well on the Virgin River floodplain demonstrated the potential for continuous pumping to threaten phreatophytic vegetation

Glutathione treatment protects the rat liver against injury after warm ischemia and Kupffer cell activation

Background/Aim: The generation of reactive oxygen species by activated Kupffer cells (KC) may contribute to reperfusion injury of the liver during liver transplantation or resection. The aim of our present studies was to investigate (1) prevention of hepatic reperfusion injury after warm ischemia by administration of the antioxidant glutathione (GSH) and (2) whether GSH confers protection through influences on KC toxicity. Methods: Isolated perfused rat livers were subjected to 1 h of warm ischemia followed by 90 min of reperfusion without (n = 5) or with GSH or catalase (n = 4-5 each). Selective KC activation by zymosan (150 mug/ml) in continuously perfused rat livers was used to investigate KC-related liver injury. Results: Postischemic infusion of 0.1, 0.5, 1.0 and 2.0 mM GSH, but not 0.05 mM GSH prevented reperfusion injury after warm ischemia as indicated by a marked reduction of sinusoidal LDH efflux by up to 83 +/- 13% (mean +/- SD; p < 0.05) and a concomitant significant improvement of postischemic bile flow by 58 +/- 27% (p < 0.05). A similar protection was conveyed by KC blockade with gadolinium chloride indicating prevention of KC-related reperfusion injury by postischemic GSH treatment. Postischemic treatment with catalase (150 U/ml) resulted in a reduction of LDH efflux by 40 +/- 9% (p < 0.05). Accordingly, catalase as well as GSH (0.1-2.0 mM) nearly completely prevented the increase in LDH efflux following selective :KC activation by zymosan in continously perfused rat livers. Conclusion: Postischemic administration of GSH protects the liver against reperfusion injury after warm ischemia. Detoxification of KC-derived hydrogen peroxide seem to be an important feature of the protective mechanisms. Copyright (C) 2002 S. Karger AG, Basel

Computer Science's Digest Volume 2

This series of textbooks was created for the students of the Systems Engineering Program at the University of Nariño. They have been intentionally written in English to promote reading in a foreign language. The textbooks are a collection of reflections and workshops on specific situations in the field of computer science, based on the authors’ experiences. The main purpose of these textbooks is essentially academic. The way in which the reflections and workshops were constructed follows a didactic structure, to facilitate teaching and learning, making use of English as a second language. This book covers Internet and Multimedia Technology, System Analysis and Design, and Software Engineerin

Pathophysiology, diagnosis, and treatment of spinal meningoceles and arachnoid cysts

Though the nomenclature regarding spinal arachnoid cysts and meningoceles is confusing and sometimes overlapping, spinal arachnoid cysts and meningoceles are distinct entities with different presentations and etiologies. Meningoceles are usually congenital lesions discovered at infancy with a high incidence of associated anomalies. Spinal arachnoid cysts are most often asymptomatic but can cause nerve root and/or cord compression. We review the presentation, pathophysiology, and management of these lesions

The NextGen Model Atmosphere grid: II. Spherically symmetric model atmospheres for giant stars with effective temperatures between 3000 and 6800~K

We present the extension of our NextGen model atmosphere grid to the regime of giant stars. The input physics of the models presented here is nearly identical to the NextGen dwarf atmosphere models, however spherical geometry is used self-consistently in the model calculations (including the radiative transfer). We re-visit the discussion of the effects of spherical geometry on the structure of the atmospheres and the emitted spectra and discuss the results of NLTE calculations for a few selected models.Comment: ApJ, in press (November 1999), 13 pages, also available at http://dilbert.physast.uga.edu/~yeti/PAPERS and at ftp://calvin.physast.uga.edu/pub/preprints/NG-giants.ps.g

Quaternary Integrated Pest Management concept for powdery mildew in sugar beet. III. Economic damage threshold and loss prediction

Die ökonomische Schadensschwelle sowie die Verlustprognose sind Teil des Quaternären IPS (Integriertes Pflanzenschutz-System) –Konzeptes zur Bekämpfung des Echten Mehltaus in Zuckerrüben. Nach Auswertung von 73 Feldversuchen (1993-2004), durchgeführt unter den klimatischen Bedingungen Mitteleuropas, vermag der Echte Mehltau Verluste an bereinigtem Zuckerertrag von 10-15% auszulösen, der Zuckergehalt kann maximal um 0,5-0,7% (absolut) gemindert sein. Hohe Verluste sind wahrscheinlich unter der Bedingung eines frühen Epidemiebeginns im Juli sowie hoher Anfälligkeit der Zuckerrübensorte. Derartige Bedingungen führen ebenso zu einer Steigerung des αAmino-Stickstoff-Gehaltes, wodurch die Ausbeute an Zucker um 1-2% verringert wird. Die übrigen Nicht-Zuckerstoffe werden durch den Mehltau-Befall nicht signifikant beeinflusst. Unter Zusammenfassung aller Ertrags- und Qualitätsfaktoren wird mit Hilfe von Befalls-Verlust-Relationen unter Zugrundelegung des AUDPC (Area Under Disease Progress Curve) -Wertes eine wirtschaftliche Schadensschwelle von 2 definiert, gleichzusetzen mit einem Zuckerverlust von 1,8%. Im Hinblick auf eine Prognose von Verlusten ist die Überschreitung der wirtschaftlichen Schadensschwelle wahrscheinlich, sofern Erstbefall vor Mitte August auftritt. Im Falle von hoch anfälligen Sorten ist die Risikoperiode bis Ende August auszudehnen. Die Risikoperioden entsprechen den Behandlungszeiträumen für Fungizidapplikationen gegen den Echten Mehltau der Zuckerrübe.The economic damage threshold and loss prediction are part of the Quaternary IPM (Integrated Pest Management) -concept developed for the control of powdery mildew in sugar beets. The evaluation of 73 field trials, conducted under the climatic conditions in central Europe (1993-2004), established that powdery mildew may cause 10-15% sugar yield losses and 0.5-0.7&nbsp;% (absolute) reductions of sugar content at the maximum. The losses occur preferably under conditions of early disease initiation in July and high susceptibility of cultivar. Such situations also may increase the content of αAminoNitrogen and, therefore, the recovery of sugar may be reduced by 1-2%. The other non sucrose components are not affected through powdery mildew. Derived from disease loss relationships and after summarising all yield and quality factors, the value of AUDPC (Area Under Disease Progress Curve) 2, equal to a sugar yield loss of 1.8&nbsp;%, is defined as the economic damage threshold. In view of loss prediction, the exceeding of the economic damage threshold is likely if first symptoms appear before mid-August, the risk period is extended to the end of August in case of high susceptibility of cultivar. The risk periods are equal to action zones for fungicide treatments

The effect of caffeine on cognitive performance is influenced by CYP1A2 but not ADORA2A genotype, yet neither genotype affects exercise performance in healthy adults

Purpose: To determine the influence of two commonly occurring genetic polymorphisms on exercise, cognitive performance, and caffeine metabolism, after caffeine ingestion. Methods: Eighteen adults received caffeine or placebo (3 mg kg−1) in a randomised crossover study, with measures of endurance exercise (15-min cycling time trial; 70-min post-supplementation) and cognitive performance (psychomotor vigilance test; PVT; pre, 50 and 95-min post-supplementation). Serum caffeine and paraxanthine were measured (pre, 30 and 120-min post-supplementation), and polymorphisms in ADORA2A (rs5751876) and CYP1A2 (rs762551) genes analysed.Results: Caffeine enhanced exercise performance (P  0.05). Caffeine enhanced PVT performance (P  0.05). Serum caffeine and paraxanthine responses were not different between genotypes (P > 0.05).Conclusion: Caffeine enhanced CYP1A2 ‘fast’ metabolisers’ cognitive performance more than ‘slow’ metabolisers. No other between-genotype differences emerged for the effect of caffeine on exercise or cognitive performance, or metabolism