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Drain
Kinds of Drain Terms modified by Drain Selected AbstractsA COMPLEXITY DRAIN ON CELLS IN THE EVOLUTION OF MULTICELLULARITYEVOLUTION, Issue 3 2002Daniel W. McShea Abstract A hypothesis has been advanced recently predicting that, in evolution, as higher-level entities arise from associations of lower-level organisms, and as these entities acquire the ability to feed, reproduce, defend themselves, and so on, the lower-level organisms will tend to lose much of their internal complexity (McShea 2001a). In other words, in hierarchical transitions, there is a drain on numbers of part types at the lower level. One possible rationale is that the transfer of functional demands to the higher level renders many part types at the lower level useless, and thus their loss in evolution is favored by selection for economy. Here, a test is conducted at the cell level, comparing numbers of part types in free-living eukaryotic cells (protists) and the cells of metazoans and land plants. Differences are significant and consistent with the hypothesis, suggesting that tests at other hierarchical levels may be worthwhile. [source] Quantifying diffuse pathways for overland flow between the roads and streams of the mountain ash forests of central Victoria AustraliaHYDROLOGICAL PROCESSES, Issue 9 2006Patrick N. J. Lane Abstract Limiting connectivity between road runoff sources and stream networks is crucial for preservation of water quality in forested environments. Where flow is non-eroding, the length of hillslope available to accommodate volumes of discharged water is the key to restricting connectivity. Hairsine et al. (2002, Hydrological Processes16: 2311,2327) proposed a probabilistic model of diffuse overland flow that predicted the hillslope lengths required to infiltrate road discharge, based on the concept of volume to breakthrough (Vbt). This paper extends this analysis to a different forest environment with the aim of testing the portability of the Hairsine et al. (2002) model. The volume of flow required to travel overland to a distance of 5 and 10 m (Vbt5 and Vbt10) from drainage outlets was measured in deep, highly conductive mountain soils in the Upper Tyers catchment, Victoria, Australia. Rainfall, hydraulic conductivity and soil depths contrasted markedly with those in the Hairsine et al. (2002) study, and represent an extreme in Australian forests. Statistical analyses revealed the population of Vbt5 to be indistinguishable from that observed by Hairsine et al. (2002), indicating the model is valid for a range of forest soils. There was no significant correlation of sediment plume length with site characteristics such as slope, width of flow, or existence of incised pathways. It is suggested there are universal properties of pathways draining tracks and roads, with bioturbation acting to restore available pore spaces filled by antecedent plumes. Drain discharge design criteria may be developed for local conditions using the Hairsine et al. (2002) model, providing a robust tool for protection of water quality in the siting of new forest roads, and maintenance of exiting roads and tracks. Copyright © 2006 John Wiley & Sons, Ltd. [source] Controlled drainage effects on water quality under semi-arid conditions in the western delta of EgyptIRRIGATION AND DRAINAGE, Issue 4 2001M.A.S. Wahba le drainage contrôlé; le drainage conventionnel; la gestion de la liste de l'eau; la qualité de l'eau de drainage Abstract Field experiments were conducted for two years in the Western Delta of Egypt to investigate the effects of controlled drainage on the quality of subsurface drainage outflows. Two water table management methods were applied in the 2.54 ha experimental field: free conventional subsurface drainage and controlled drainage. Controlled drainage was applied at 60 cm depth during both seasons. Drain discharge volumes and nitrate-N and orthophosphate-phosphorus concentrations were monitored during the growing seasons. The controlled drainage (CD) treatment significantly reduced the total drainage outflow by 68% during the summer season and by 28% during the winter of 1999,2000 at 99% confidence level, compared to free conventional drainage (FD) treatment. The CD also reduced the total nitrate-N in drainage water by 73%, and 32% during the summer and the winter seasons respectively, compared to the FD treatment. The CD treatment reduced the total orthophosphate-phosphorus losses by 77% during summer of 1999 and by 30% during winter of 1999,2000 compared to the FD treatment; however, in general the total mass loss was low in both treatments. The results of the experiment showed the potential environmental and economic benefits with the application of controlled drainage in semi-arid regions. Copyright © 2001 John Wiley & Sons, Ltd. Les expériences sur les domaines étaient dirigées pour deux ans dans le delta de l'ouest de l'Egypte, pour étudier les effets du drainage contrôlé sur la qualité de l'écoulement du drainage sous-surface. Deux méthodes du direction de table de l'eau ont été appliquées sur environ 2.54 ha domaines d'expériences, du drainage conventionnel sous-surface libre, et du drainage contrôlé. Le drainage contrôlé était appliqué a 60 cm de profondeur durant les deux saisons, les concentrations des volumes du drain déchargé et du nitrate-N, et les orthophosphate-phosphours étaient surveillées durant les saisons nouvelles. Le drainage contrôlé (DC) traitement a diminué considérablement le total de charge du drainage par taux de 68% durant l'été et par 28% pendant l'hiver de 1999,2000 par 99%, le niveau de confiance en comparaison au traitement du drainage conventionnel libre (DL). Le drainage contrôlé a diminué le taux total du nitrate-N dans l'eau de drainage par taux de 73% pendant l'été et 32% pendant l'hiver comparé avec le traitement du drainage libre. Le drainage contrôlé du taux total d'orthophosphate-phosphours perdu a diminué par 77% pendant l'été 1999, et 30% pendant l'hiver de 1999,2000 comparé avec le traitement du drainage libre, mais en général la masse totale perdue a diminué. Les résultats ont présenté le potentiel environnemental et les bénéfits économiques de l'application du drainage contrôlé dans les régions semi-arides. Copyright © 2001 John Wiley & Sons, Ltd. [source] A review of the importance of freshwater inflow to the future conservation of Lake St LuciaAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009A. K. Whitfield Abstract 1.Lake St Lucia, the oldest formally protected estuary in the world is under threat from historic and present manipulation of freshwater supplies to the system. 2.Constraints to the functioning of the ecosystem began in 1914 with the commencement of draining and canalization of the Mfolozi Swamp to open up the swamp and river floodplain for sugar cane cultivation. Warner's Drain was completed in 1936 and the sediment filtering capability of the swamp on river floodwaters was effectively removed. This resulted in exceptionally high sediment loads from the Mfolozi River entering directly into the St Lucia system and the river was therefore diverted southwards and provided with a separate estuary mouth. This deprived St Lucia of its single largest freshwater supply. 3.During the past 50,60 years, increasing freshwater abstractions from the Mkhuze, Mzinene, Hluhluwe and Nyalazi rivers have contributed to the increasingly severe salinity extremes experienced by Lake St Lucia. In the past decade, desiccation of large areas of False Bay, North and South Lake has occurred, due primarily to natural estuary mouth closure combined with a prolonged drought and unnaturally low freshwater inflows during the closed phase. These events have pushed the system into an extreme state that has not been recorded previously and would not have occurred if Mfolozi River water had been available to the St Lucia system over this drought period. 4.Forestry plantations have further exacerbated the freshwater supply situation, although recent removal of pine plantations on the eastern and western shores of the lake are likely to help restore groundwater flows to the system. 5.This review explores the possibility of relinking the Mfolozi River, once the Mfolozi floodplain swamp has been re-established, to the St Lucia system, thereby bringing urgently needed fresh water to this threatened World Heritage Site. Copyright © 2009 John Wiley & Sons, Ltd. [source] The ,Brain Drain': Australian responsibilityAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 4 2005Jeanne Daly No abstract is available for this article. [source] The Role of Surface Water Drainage in Environmental Change: a Case Example of the Upper South East of South Australia; an Historical ReviewGEOGRAPHICAL RESEARCH, Issue 3 2001Kathryn H. Taffs The role of surface water drainage in environmental change in Australia is rarely appreciated. Drains can modify surface water hydrology, not only altering flow regimes but also rapidly dispersing contaminants and altering the natural hydrological balance of associated flora and fauna. Yet drainage continues to be considered a viable management strategy rather than as a cause of land degradation. The impact of surface water drainage in an inherently saline area of South Australia, the Upper South East, is investigated. Surface water drains were constructed by developers in an attempt to increase the area of land available and viable for agricultural land use. Drainage strategies altered the natural direction, magnitude and frequency of surface water flow. The Upper South East has experienced periods of both increased surface water and flooding, and surface water deficit, in the past one hundred years. The region now receives less surface water than under pre-European conditions, but local runoff is channelled into and through the wetlands more rapidly than before European settlement. Future management strategies are likely to continue this trend, to the detriment of remnant natural wetlands. [source] THERAPEUTIC FISTULOSCOPY FOR THE MANAGEMENT OF PROLONGED POSTOPERATIVE INTRA-ABDOMINAL ABSCESS CAUSED BY SMALL INTESTINAL PINHOLE PERFORATIONDIGESTIVE ENDOSCOPY, Issue 4 2005Yoshihisa Saida Fistuloscopy is an effective treatment for intractable fistula, a sometimes difficult to manage postoperative intra-abdominal complication. A case of a 69-year-old male with an abdominal abscess after he underwent right hemi-colectomy for cecum cancer with invasions into the ileum and sigmoid colon is reported. A re-operation for lavage and drainage was performed 2 weeks after surgery. However, no obvious origin for the pus was located. Although physiological saline lavage was repeatedly performed, the effusion of pus persisted in the drain at the midline incision about 7 months after surgery. Then, fistuloscopy with an upper gastrointestinal endoscope was performed through the hole of the tube. A pinhole that produced a bubble just below the midline incision was observed. Then, an endoscopic retrograde cholangiopancreatography (ERCP) tube was inserted to obtain images of the small intestine by fluorography and findings suggested a diagnosis of perforation of the small intestine, which appeared to explain why resolution of the abscess was prolonged. After direct drainage to the small intestine with a 40-cm-long 7 Fr percutaneous transhepatic cholangio drainage (PTCD) balloon catheter, pus from the tube notably decreased. After confirming that the abscess cavity had disappeared by abdominal computed tomography scan, the PTCD catheter was extracted about 8 months after primary surgery. Since then, no recurrence of cancer or abscess has been observed. In cases of intractable postoperative intra-abdominal abscess, fistuloscopy using smaller diameter gastrointestinal endoscopy appears to be a valuable diagnostic tool. [source] In situ water and sediment toxicity in an agricultural watershedENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2004Bryn M. Phillips Abstract The Salinas River receives inputs from extensive farmlands before flowing into the Salinas River National Wildlife Refuge and the Monterey Bay National Marine Sanctuary (CA, USA). Previous monitoring using laboratory toxicity tests and chemical analyses identified toxic agricultural drain-water inputs in this system. Using caged daphnids (Ceriodaphnia dubia) and amphipods (Hyalella azteca), we investigated in situ toxicity at stations downstream from an agricultural drain relative to a reference station. A flow sensor indicated highly variable inputs from irrigation, and daily synoptic chemical analyses using enzyme-linked immunosorbent assay techniques demonstrated fluctuating concentrations of organophosphate pesticides. Test organism mortality in the field coincided with contaminant concentrations that exceeded chemical effect thresholds for the test species. Laboratory toxicity tests using C. dubia were comparable to results from field exposures, but tests with H. azteca were not. Laboratory exposures can be reasonable surrogates for field evaluations in this system, but they were less effective for assessing short-term temporal variability. Results from the field toxicity studies corroborated results of bioassessment surveys conducted as part of a concurrent study. Toxicity identification evaluations indicated that organophosphate pesticides caused toxicity to daphnids and that effects of suspended solids were negligible. [source] Ecotoxicologic impacts of agricultural drain water in the Salinas River, California, USAENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2003Brian S. Anderson Abstract The Salinas River is the largest of the three rivers that drain into the Monterey Bay National Marine Sanctuary in central California (USA). Large areas of this watershed are cultivated year-round in row crops, and previous laboratory studies have demonstrated that acute toxicity of agricultural drain water to Ceriodaphnia dubia is caused by the organophosphate (OP) pesticides chlorpyrifos and diazinon. We investigated chemical contamination and toxicity in waters and sediments in the river downstream of an agricultural drain water input. Ecological impacts of drain water were investigated by using bioassessments of macroinvertebrate community structure. Toxicity identification evaluations were used to characterize chemicals responsible for toxicity. Salinas River water downstream of the agricultural drain was acutely toxic to the cladoceran Ceriodaphnia dubia, and toxicity to C. dubia was highly correlated with combined toxic units (TUs) of chlorpyrifos and diazinon. Laboratory tests were used to demonstrate that sediments in this system were acutely toxic to the amphipod Hyalella azteca, a resident invertebrate. Toxicity identification evaluations (TIEs) conducted on sediment pore water suggested that toxicity to amphipods was due in part to OP pesticides; concentrations of chlorpyrifos in pore water sometimes exceeded the 10-d mean lethal concentration (LC50) for H. azteca. Potentiation of toxicity with addition of the metabolic inhibitor piperonyl butoxide suggested that sediment toxicity also was due to other non,metabolically activated compounds. Macroinvertebrate community structure was highly impacted downstream of the agricultural drain input, and a number of macroinvertebrate community metrics were negatively correlated with combined TUs of chlorpyrifos and diazinon, as well as turbidity associated with the drain water. Some macroinvertebrate metrics were also correlated with bank vegetation cover. This study suggests that pesticide pollution is the likely cause of ecological damage in the Salinas River, and this factor may interact with other stressors associated with agricultural drain water to impact the macroinvertebrate community in the system. [source] Measurement of the size distribution of water-filled pores at different matric potentials by stray field nuclear magnetic resonanceEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2005N. R. A. Bird Summary The water retention characteristic provides the traditional data set for the derivation of a soil's pore-size distribution. However, the technique employed to achieve this requires that assumptions be made about the way pores interconnect. We explore an alternative approach based on stray field nuclear magnetic resonance (STRAFI-NMR) to probe the water-filled pores of both saturated and unsaturated soils, which does not require information relating to pore connectivity. We report the relative size distributions of water-occupied pores in saturated and unsaturated samples of two sets of glass beads of known particle size, two sands, and three soils (a silty loam, a sandy loam and a loamy sand), using measurements of the NMR T1 proton relaxation time of water. The T1 values are linearly related to pore size and consequently measured T1 distributions provide a measure of the pore-size distribution. For both the sands and the glass beads at saturation the T1 distributions are unimodal, and the samples with small particle sizes show a shift to small T1 values indicating smaller voids relative to the samples with larger particles. Different matric potentials were used to reveal how the water-occupied pore-size distribution changes during drainage. These changes are inconsistent with, and demonstrate the inadequacies of, the commonly employed parallel-capillary tube model of a soil pore space. We find that not all pores of the same size drain at the same matric potential. Further, we observe that the T1 distribution is shifted to smaller values beyond the distribution at saturation. This shift is explained by a change in the weighted average of the relaxation rates as the proportion of water in the centre of water-filled pores decreases. This is evidence for the presence of pendular structures resulting from incomplete drainage of pores. For the soils the results are similar except that at saturation the T1 distributions are bimodal or asymmetrical, indicative of inter-aggregate and intra-aggregate pore spaces. We conclude that the NMR method provides a characterization of the water-filled pore space which complements that derived from the water retention characteristic and which can provide insight into the way pore connectivity impacts on drainage. [source] A COMPLEXITY DRAIN ON CELLS IN THE EVOLUTION OF MULTICELLULARITYEVOLUTION, Issue 3 2002Daniel W. McShea Abstract A hypothesis has been advanced recently predicting that, in evolution, as higher-level entities arise from associations of lower-level organisms, and as these entities acquire the ability to feed, reproduce, defend themselves, and so on, the lower-level organisms will tend to lose much of their internal complexity (McShea 2001a). In other words, in hierarchical transitions, there is a drain on numbers of part types at the lower level. One possible rationale is that the transfer of functional demands to the higher level renders many part types at the lower level useless, and thus their loss in evolution is favored by selection for economy. Here, a test is conducted at the cell level, comparing numbers of part types in free-living eukaryotic cells (protists) and the cells of metazoans and land plants. Differences are significant and consistent with the hypothesis, suggesting that tests at other hierarchical levels may be worthwhile. [source] Crystal structures of isomaltase from Saccharomyces cerevisiae and in complex with its competitive inhibitor maltoseFEBS JOURNAL, Issue 20 2010Keizo Yamamoto The structures of isomaltase from Saccharomyces cerevisiae and in complex with maltose were determined at resolutions of 1.30 and 1.60 Å, respectively. Isomaltase contains three domains, namely, A, B, and C. Domain A consists of the (,/,)8 -barrel common to glycoside hydrolase family 13. However, the folding of domain C is rarely seen in other glycoside hydrolase family 13 enzymes. An electron density corresponding to a nonreducing end glucose residue was observed in the active site of isomaltase in complex with maltose; however, only incomplete density was observed for the reducing end. The active site pocket contains two water chains. One water chain is a water path from the bottom of the pocket to the surface of the protein, and may act as a water drain during substrate binding. The other water chain, which consists of six water molecules, is located near the catalytic residues Glu277 and Asp352. These water molecules may act as a reservoir that provides water for subsequent hydrolytic events. The best substrate for oligo-1,6-glucosidase is isomaltotriose; other, longer-chain, oligosaccharides are also good substrates. However, isomaltase shows the highest activity towards isomaltose and very little activity towards longer oligosaccharides. This is because the entrance to the active site pocket of isomaltose is severely narrowed by Tyr158, His280, and loop 310,315, and because the isomaltase pocket is shallower than that of other oligo-1,6-glucosidases. These features of the isomaltase active site pocket prevent isomalto-oligosaccharides from binding to the active site effectively. [source] Sensing of Alkylating Agents Using Organic Field-Effect TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Yair Gannot Abstract Alkylating agents are simple and reactive molecules that are commonly used in many and diverse fields, such as organic synthesis, medicine, and agriculture. Some highly reactive alkylating species are also being used as blister chemical warfare agents. The detection and identification of alkylating agent is not a trivial issue because of their high reactivity and simple structure. Here, a novel polythiophene derivative that is capable of reacting with alkylating agents is reported, along with its application in direct electrical sensing of alkylators using an organic field-effect transistor, OFET, device. Upon reacting with alkylators, the OFET containing the new polythiophene analogue as its channel becomes conductive, and the gate effect is lost; this is in marked contrast to the response of the OFET to "innocent" vapors, such as alcohols and acetone. By following the drain,source current under gate bias, one can easily follow the processes of absorption of the analyte to the polythiophene channel and their subsequent reaction. [source] Application of Superposition with Nonlinear Head-Dependent FluxesGROUND WATER, Issue 2 2008Timothy Durbin While superposition is commonly used to address linear ground water problems, it can also be used to address certain nonlinear problems. In particular, it can be used to address problems with nonlinear head-dependent fluxes, where the problem can be separated conveniently into steady-state and transient-state components. Superposition can be used to simulate the transient-state head changes independently from the steady-state heads. The problems addressable by superposition include phreatophyte discharges, stream-aquifer interactions, spring discharges, and drain discharges. Each of these represents a nonlinear head-dependent flux, where the flux depends on the elevation of the land surface or some other feature. Superposition is applied by referencing elevations to the local steady-state water table and by imposing the negative of the steady-state flux on the transient-state problem. [source] Ionic/Electronic Hybrid Materials Integrated in a Synaptic Transistor with Signal Processing and Learning FunctionsADVANCED MATERIALS, Issue 22 2010Qianxi Lai A synaptic transistor is fabricated by integrating ionic/electronic hybrid materials to emulate biological synapses with spike signal processing, learning, and memory functions. A potential spike generates transient ionic fluxes in a polymer layer in the transistor gate, triggering an excitatory postsynaptic current in the transistor drain. Temporally correlated pre- and post-synaptic spikes modify ions stored in the polymer, resulting in the nonvolatile modification of the transistor with spike-timing-dependent plasticity. [source] Simulating daily soil water under foothills fescue grazing with the soil and water assessment tool model (Alberta, Canada)HYDROLOGICAL PROCESSES, Issue 15 2004Emmanuel Mapfumo Abstract Grazing is common in the foothills fescue grasslands and may influence the seasonal soil-water patterns, which in turn determine range productivity. Hydrological modelling using the soil and water assessment tool (SWAT) is becoming widely adopted throughout North America especially for simulation of stream flow and runoff in small and large basins. Although applications of the SWAT model have been wide, little attention has been paid to the model's ability to simulate soil-water patterns in small watersheds. Thus a daily profile of soil water was simulated with SWAT using data collected from the Stavely Range Sub-station in the foothills of south-western Alberta, Canada. Three small watersheds were established using a combination of natural and artificial barriers in 1996,97. The watersheds were subjected to no grazing (control), heavy grazing (2·4 animal unit months (AUM) per hectare) or very heavy grazing (4·8 AUM ha,1). Soil-water measurements were conducted at four slope positions within each watershed (upper, middle, lower and 5 m close to the collector drain), every 2 weeks annually from 1998 to 2000 using a downhole CPN 503 neutron moisture meter. Calibration of the model was conducted using 1998 soil-water data and resulted in Nash,Sutcliffe coefficient (EF or R2) and regression coefficient of determination (r2) values of 0·77 and 0·85, respectively. Model graphical and statistical evaluation was conducted using the soil-water data collected in 1999 and 2000. During the evaluation period, soil water was simulated reasonably with an overall EF of 0·70, r2 of 0·72 and a root mean square error (RMSE) of 18·01. The model had a general tendency to overpredict soil water under relatively dry soil conditions, but to underpredict soil water under wet conditions. Sensitivity analysis indicated that absolute relative sensitivity indices of input parameters in soil-water simulation were in the following order; available water capacity > bulk density > runoff curve number > fraction of field capacity (FFCB) > saturated hydraulic conductivity. Thus these data were critical inputs to ensure reasonable simulation of soil-water patterns. Overall, the model performed satisfactorily in simulating soil-water patterns in all three watersheds with a daily time-step and indicates a great potential for monitoring soil-water resources in small watersheds. Copyright © 2004 John Wiley & Sons, Ltd. [source] Microcontact Printing as a Versatile Tool for Patterning Organic Field - Effect Transistors,ADVANCED MATERIALS, Issue 12 2005R. Parashkov Patterning of organic field-effect transistors can be easily accomplished by microcontact printing combined with subsequent electroplating and electrode-peeling transfer. The method is based on area-selective electrodeposition and diffusion electropolymerization performed on metallized substrates with a previously patterned self-assembled monolayer, which is used as a template in the subsequent deposition of drain and source contacts (see Figure). [source] Functionalized Arylacetylene Oligomers for Organic Thin-Film Transistors (OTFTs),ADVANCED MATERIALS, Issue 10 2005Oligo(arylacetylene)-based organic thin-film transistors (OTFTs) possess good structural order and smooth film morphologies, and exhibit field-effect mobilities of 0.3,cm2,V,1,s,1, one of the highest field-effect mobilities reported for an OTFT device that does not possess a self-assembled-layer configuration. The Figure shows the measured output characteristics (drain,source current, IDS versus drain,source voltage, VDS) at different gate voltages (VG). [source] An efficient neural network approach for nanoscale FinFET modelling and circuit simulationINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2009M. S. Alam Abstract The present paper demonstrates the suitability of artificial neural network (ANN) for modelling of a FinFET in nano-circuit simulation. The FinFET used in this work is designed using careful engineering of source,drain extension, which simultaneously improves maximum frequency of oscillation ,max because of lower gate to drain capacitance, and intrinsic gain AV0,=,gm/gds, due to lower output conductance gds. The framework for the ANN-based FinFET model is a common source equivalent circuit, where the dependence of intrinsic capacitances, resistances and dc drain current Id on drain,source Vds and gate,source Vgs is derived by a simple two-layered neural network architecture. All extrinsic components of the FinFET model are treated as bias independent. The model was implemented in a circuit simulator and verified by its ability to generate accurate response to excitations not used during training. The model was used to design a low-noise amplifier. At low power (Jds,10,µA/µm) improvement was observed in both third-order-intercept IIP3 (,10,dBm) and intrinsic gain AV0 (,20,dB), compared to a comparable bulk MOSFET with similar effective channel length. This is attributed to higher ratio of first-order to third-order derivative of Id with respect to gate voltage and lower gds in FinFET compared to bulk MOSFET. Copyright © 2009 John Wiley & Sons, Ltd. [source] Accurate substrate modelling of RF CMOSINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 3 2006M. S. Alam Abstract The losses within the substrate of an RF IC can have significant effect on performance in a mixed signal application. In order to model substrate coupling accurately, it is represented by an RC network to account for both resistive and dielectric losses at high frequency (> 1 GHz). A small-signal equivalent circuit model of an RF IC inclusive of substrate parasitic effect is analysed in terms of its y -parameters and an extraction procedure for substrate parameters has been developed. By coupling the extracted substrate parameters along with extrinsic resistances associated with gate, source and drain, a standard BSIM3 model has been extended for RF applications. The new model exhibits a significant improvement in prediction of output reflection coefficient S22 in the frequency range from 1 to 10 GHz in device mode of operation and for a low noise amplifier (LNA) at 2.4 GHz. Copyright © 2006 John Wiley & Sons, Ltd. [source] Cost-effective laparoscopic pyeloplasty: Single center experienceINTERNATIONAL JOURNAL OF UROLOGY, Issue 11 2003ASHOK KUMAR HEMAL Summary Objective:, Laparoscopic pyeloplasty (LPP) is a minimally invasive treatment option for ureteropelvic junction (UPJ) obstruction. We report here our experience of performing cost-effective LPP on 24 patients at a single center. Methods:, Between October 1999 and March 2002, LPP was performed in 24 patients (17 male, seven female; age range 8,51 years) including two patients who had failed previous endourologic treatments. In two patients with concomitant renal stones, laparoscopic pyelolithotomy was also performed. LPP was conducted in a cost-reductive manner by both transperitoneal (n = 12) and retroperitoneal (n = 12) access. To reduce the cost, an indigenous balloon to create the retroperitoneal space, reusable ports, ordinary polyglactin suture and intracorporeal free-hand suturing were employed. To reduce operative time, antegrade stenting was also performed in some cases. Results:, Laparoscopic Anderson,Hynes pyeloplasty was performed in 16, Foley Y,V pyeloplasty in five and Fenger pyeloplasty in three patients. One patient required conversion to open surgery due to tension at the anastomosis site during Anderson,Hynes pyeloplasty. The mean operating time, blood loss, analgesic (pethidine) requirement, duration of drain and hospital stay for the retroperitoneal and transperitoneal groups were 170.3 and 187.6 min, 102.2 and 145.9 mL, 125 and 136.4 mg, 2.1 and 2.5 days, and 3.4 and 4.3 days, respectively. No significant complications were encountered apart from prolonged ileus in three patients in the transperitoneal group. The mean follow-up period was 10.8 months with a range of 2,24 months. Postoperative renal scan was performed at 3 months in 21 patients, and 1 year in 11 patients. There was evidence of equivocal obstruction in one patient, but there were no obstructions in the remaining patients. Conclusion:, Although LPP is technically demanding, it is emerging as a viable, minimally invasive alternative to open pyeloplasty for UPJ obstruction with a success rate similar to that of open pyeloplasty. It allows the duplication of open surgery steps (unlike endoscopic procedures), thereby providing durable and sustained results. LPP can also be performed safely, effectively and efficiently in a cost-efficient manner. [source] Regional Organizations and Intra-Regional Migration in Sub-Saharan Africa: Challenges and ProspectsINTERNATIONAL MIGRATION, Issue 6 2001Aderanti Adepoju Africa is a region of diverse migration circuits relating to origin, destination and transit for labour migrants, undocumented migrants, refugees and brain circulation of professionals. This article outlines major migration configurations in the region, and the role of two vibrant subregional organizations , Economic Community of West African States and South African Development Community , in facilitating, containing or curtailing intra-regional migration which takes place within diverse political, economic, social and ethnic contexts; the transformation of brain drain into brain circulation; and commercial migration in place of labour migration within the region. Despite overlapping membership, wavering political support, a poor transportation network, border disputes and expulsions, these subregional organizations are crucial for the region's collective integration into the global economy, and to enhance economic growth and facilitate labour intraregional migration. Free movement of persons without visa, adoption of ECOWAS travellers' cheques and passports, the creation of a borderless Community; and the granting of voting rights and later citizenship and residence permits by South Africa to migrant workers from SADC countries are positive developments. These organizations need to foster cooperation between labour-exporting and recipient countries, implement the protocols on the right of residence and establishment; promote dialogue and cooperation in order to harmonize, coordinate and integrate their migration policies as envisioned by the 1991 Abuja Treaty establishing the African Economic Community. [source] Surgical site infection rate and associated risk factors in elective general surgery at a public sector medical university in PakistanINTERNATIONAL WOUND JOURNAL, Issue 1 2008Ahmed Khan Sangrasi Abstract This prospective study aimed to determine the surgical site infection (SSI) rate and associated risk factors was carried in a general surgical ward at Liaquat University Hospital Jamshoro. A total of 460 patients requiring elective general surgery from July 2005 to June 2006 were included in this study. All four surgical wound categories were included. Primary closure was employed in all cases. Patients were followed up to 30th day postoperatively. All cases were evaluated for postoperative fever, redness, swelling of wound margins and collection of pus. Cultures were taken from all the cases with any of the above finding. Mean ± SD age of the patients was 38·8 ± 17·4 years with male to female ratio of 1·5:1. The overall rate of surgical site infection was 13·0%. The rate of wound infection was 5·3% in clean operations, 12·4% in clean-contaminated, 36·3% in contaminated and 40% in dirt-infected cases. Age, use of surgical drain, duration of operation and wound class were significant risk factors for increased surgical site infection (P < 0·05). Postoperative hospital stay was double in cases who had surgical site infection. Sex, haemoglobin level and diabetes were not statistically significant risk factors (P > 0·05). In conclusion, surgical site infection causes considerable morbidity and economic burden. The routine reporting of SSI rates stratified by potential risk factors associated with increased risk of infection is highly recommended. [source] Negative pressure wound therapy: treating a venomous insect biteINTERNATIONAL WOUND JOURNAL, Issue 1 2007Michael S Miller Abstract Reports of spider bites appear throughout North America. Bites associated with the brown recluse spider (Loxosceles recluse) cause serious medical complications because the venom of this spider contains a powerful necrotising agent with the potential to cause severe cutaneous necrosis. Although not much is known regarding the application of negative pressure wound therapy (NPWT) to spider bites, this therapy has considerable literature support for its efficacy, cost-effectiveness and ease of use in chronic, difficult-to-heal wounds. A case study using NPWT to successfully treat a non healing upper arm wound presumed due to a venomous spider bite is presented here. The patient was successfully treated with a new, less costly NPWT product called the Versatile 1® and a new combination drain plus dressing called the Miller DermiVex® drain, both manufactured by Blue Sky Medical (Carlsbad, CA). [source] Optimization of water management in the RUT Irrigation District, Colombia,IRRIGATION AND DRAINAGE, Issue 1 2004Herman Depeweg canaux d'irrigation; régulation de canaux; simulation des écoulements en canal Abstract The RUT Irrigation District is a flat polder area with an infrastructure for irrigation, drainage and flood protection. Water is pumped out for drainage, mainly during the wet season and is pumped in for irrigation during the two growing seasons. The RUT Irrigation District is one of the 16 districts that were transferred by the Colombian government to a water users' association. During this process the farmers agreed to take over the management and to give up governmental subsidies. It appeared that the farmers grossly underestimated the future energy costs and nowadays they complain about high costs for operation and maintenance of the pumping stations. In addition, the service provided is not adequate and the condition of the pumps is declining. The supplementary irrigation is based on the rainfall deficit, but a distinct criterion to supply water according to daily rainfall and cropping calendar does not exist. Hence, it is possible that more water than required is supplied to the area, affecting not only the pumping costs for irrigation but also for drainage. The present situation has been evaluated with a water balance at scheme level and an analysis of the measured groundwater fluctuations. Consecutively, a water balance at field level with an unsaturated groundwater flow model has been simulated to determine the irrigation requirements, yield reduction and drain flow based on a 20-year analysis. The water balance at field level and the one-, two- and three-day rainfall with a return period of 5 years resulted in design drain flows. Finally, these flows were used in hydrodynamic simulations to analyse the pumping requirements for optimal drainage. The simulations also indicated the inundated areas to be expected for different rainfall intensities and frequencies. Copyright © 2004 John Wiley & Sons, Ltd. Le district de RUT possède un système d'irrigation et de drainage avec une protection contre les inondations. L'eau est non seulement pompée pour assurer le drainage du polder durant la saison humide, mais aussi pour alimenter le système d'irrigation durant les deux saisons agricoles. Le district de RUT est l'un des seize districts transférés par le gouvernement colombien à une association d'usagers de l'eau. Durant ce transfert, les exploitants agricoles ont accepté de prendre en charge la gestion et d'abandonner les aides gouvernementales. Il est apparu alors que les exploitants agricoles se plaignent des couts élevés pour l'opération et la maintenance des stations de pompages. De plus, le service fourni n'est pas adéquat et les pompes se détériorent. L'irrigation de complément est fonction des précipitations, mais il n'existe pas de critère précis pour la fourniture d'eau en fonction de précipitations quotidiennes ou du calendr des récoltes. Il est ier possible qu'une quantité d'eau supérieure à celle requise soit apportée au système, affectant non seulement les exigences de pompage pour l'irrigation mais aussi pour le drainage. L'évaluation de la situation actuelle est basée sur un bilan hydrique à l'échelle de système et sur une analyse des fluctuations des eaux souterraines. Par la suite, un bilan hydrique a l'échelle de la campagne délivré par le model WASIM a été utilisé pour déterminer les exigences d'irrigation, la réduction des récoltes et le débit dans le drain basé sur une simulation de 20 ans. Enfin, le drain principal fut simulé avec DUFLOW pour analyser les caractéristiques du pompage pour le drainage utilisant le débit de drainage fourni par un bilan hydrique pour des durées deun, deux et trois jours de pluie fréquence de quinquennale. La simulation a aussi permis d'identifier les étendues des inondations pour différentes intensités et fréquences de pluie. Copyright © 2004 John Wiley & Sons, Ltd. [source] The role of controlled drainage under drought conditions in an irrigated area in NWFP, Pakistan,IRRIGATION AND DRAINAGE, Issue 2 2003Gul Daraz Khan sécheresse; drainage commandé; eaux souterraines; efficacité d'utilisation de l'eau et rendement Abstract The River Swat is the source of irrigation for the entire irrigation system of Mardan, Nowshera and Charsadda districts. Reductions of water and overdrainage have influenced the yield of major crops. The impact of reduced supply at the inlet from the source, drought conditions and overdrainage from the area have lowered the groundwater to a disastrous level. Thus the present groundwater level cannot contribute to the crops. A subsurface collector at its exit in drainage unit 106 was controlled to raise the watertable. The study area was divided into 10 zones. Each zone was separately assessed to analyze the groundwater impact in response to the controlled technique adopted for mitigating drought in different strategies of the canal operation. The interaction of groundwater level with irrigation depth, crop yield, water use efficiency and water saving were also studied. During the rotational period of the canal, irrigations applied in section II raised the water level by nearly 1 m. The upslope area of section III also needed a large irrigation depth. The groundwater level on the downslopes of the lateral drains in sections I and V was at the design depth of 1.1 m during the rotational strategy, while it decreased only slightly on the upslopes of the lateral drains for the same positions. Because of effective control by the collector, the watertable on the downslopes of the laterals in sections II and III was affected less while in the respective upslope area of section III it dropped more than 2 m. The water levels in section IV (both in the upslope and downslope areas along the laterals) remained very close to the design level. A significant contribution of seepage in the upslope of the collector drain considerably reduced the irrigation depths. During the canal closure period, the watertables in the study area dropped to the limit from 2.3 to 3.25 m. After the reopening of the canal, the watertables in sections II, III and IV were raised from 2.55 to 0.70 m. During this period the water levels near the canal reached the design level. The maximum yield of 6.5 tons ha,1 on the downslopes of the lateral drains in section II was obtained, resulting in maximum water use efficiency of 0.93 kg m,3. However, the minimum yield of 3.5 tons ha,1 on the upslopes of the lateral drains in section I was obtained, resulting in the lowest water use efficiency of 0.35 kg m,3 near the deep surface drain (5 m). The impact of controlled subsurface drainage in zones 2, 3 and 7 resulted in the best maintenance of optimum groundwater level and moisture content. Therefore large amounts of extra irrigation water applied (ranging from 23 to 129% of that actually required) in different zones of the controlled area can be saved for drought conditions. Copyright © 2003 John Wiley & Sons, Ltd. RÉSUMÉ Le fleuve Swat est la source d'irrigation pour les systèmes d'irrigation entiers des zones de Mardan, de Nowshera et de Charsadda. Les réductions de drainage de l'eau et d'excédent ont influencé le rendement de récoltes principales. L'impact de l'approvisionnement réduit à l'admission de la source, des conditions de sécheresse et du drainage d'excédent du secteur ont laissé tomber les eaux souterraines à un niveau désastreux. Ainsi le niveau actuel d'eaux souterraines ne peut pas contribuer aux récoltes. Un collecteur à fleur de terre à sa sortie dans l'unité 106 de drainage a été commandé pour soulever le niveau hydrostatique. Le secteur d'étude a été divisé en dix zones. Chaque zone a été séparément évaluée pour analyser l'impact d'eaux souterraines en réponse à la technique commandée adoptée pour atténuer la sécheresse dans différentes stratégies de l'opération de canal. L'interaction du niveau d'eaux souterraines sur la profondeur d'irrigation, le rendement de récolte, l'efficacité d'utilisation de l'eau et l'économie de l'eau ont été également étudié. Pendant la période de rotation du canal, les irrigations appliquées dans la section II ont élevé le niveau d'eau de presque un mètre. Le secteur demontée de la section III avait besoin d'une grande profondeur d'irrigation. Le niveau d'eaux souterraines des déscentes de la vidange latérale dans les sections I et V était à la profondeur de conception de 1.1 m pendant la stratégie de rotation, tandis qu'il diminuait seulement légèrement aux montée des drains latéraux pour les mêmes positions. En raison de la commande efficace du collecteur, le niveau hydrostatique des déscentes des parties latérales dans les sections II et III a été affecté moins, tandis que dans le secteur respectif demontée de la section III il descentait à plus de deux mètres. Les niveaux d'eau dans la section IV (tous les deux dans les secteurs demontée etde déscentes le long des parties latérales) ont demeuré très près de la conception. La contribution significative de l'infiltration dans lamontee du drain de collecteur a considérablement réduit les profondeurs d'irrigation. Pendant la période de fermeture du canal, les niveaux hydrostatiques dans le secteur d'étude sont descendus la limite de 2.3 à 3.25 m. A la réouverture du canal, les niveaux hydrostatiques dans les sections II, III et IV augmenté de 2.55 à 0.70 m. Pendant cette période les niveaux d'eau près du canal ont atteint celui de la concept. Le rendement maximum de 6.5 tons ha,1 aux déscentes des drains latéraux dans la section II a été obtenu, ayant pour résultat l'efficacité maximum d'utilisation de l'eau de 0.93 kg m,3.Cependant le rendement minimum de 3.5 tons ha,1 aux montées des drains latéraux dans la section a été obtenu, ayant pour résultat la plus basse efficacité d'utilisation de l'eau de 0.35 kg m,3 près du drain extérieur profond (5 m). L'impact du drainage à fleur de terre commandé dans les zones 2, 3 et 7 a maintenu le meillear niveau d'eaux souterraines et le contenu d'humidité optimum. Par conséquent la grande quantité de l'eau supplémentaire d'irrigation celle appliquée (s'étendant de 23 à 129% deréellement requise) dans différentes zones de la zone de contrôle peut être sauvée pour les conditions de sécheresse. Copyright © 2003 John Wiley & Sons, Ltd. [source] Perioperative Results of the Aortic Root Replacement in Strict Graft Inclusion TechniqueJOURNAL OF CARDIAC SURGERY, Issue 5 2008Niyazi Cebi M.D. Therefore, the strict graft inclusion technique has been developed to avoid major complications. We present the early results after aortic root replacement in strict graft inclusion technique. Materials and Methods: The strict graft inclusion technique was performed in 28 patients between April 2001 and June 2006 in St-Johannes-Hospital-Dortmund, Dortmund, Germany. There were nine female and 19 male patients. The mean age was 57.78 ± 12.01 years (28 to 77 years). A type A aortic dissection and an ascending aortic aneurysm with aortic valve lesion were the indication to operation in patients. Results: There were no early mortality and postoperative rethoracotomy. The mean postoperative bleeding over mediastinal drains was 565 ± 310 mL. (100,2250 mL). In exception of the patients with preoperative double thrombocyte aggregation inhibitors therapy and postoperative consumption coagulopathy, the mean postoperative bleeding over mediastinal drain was 443.04 ± 171.59 mL (100,1100) in the first 24 hours, the transfusion rate was minimal, mean 0.39 ± 0.64 packed red blood cells (RBC) (0,4) and mean 0.14 ± 0.27 packed fresh frozen plasma (FFP) (0,4), whereas only in 18 patients (78.26%) out of 23 patients was a transfusion not necessary. The intraoperative and postoperative requirement for substitution of erythrocyte concentrate was mean 1 ± 1.28 packed RBC (0,5) and FFP concentrate was mean 1.21 ± 1.90 packed FFP (0,12). Conclusions: The strict graft inclusion technique for aortic root replacement represents a safe and feasible method to avoid bleeding from coronary ostial anastomoses, from aortic annular suture lines, and annular leak. [source] A novel artificial habitat collection device for studying resettlement patterns in anguillid glass eelsJOURNAL OF FISH BIOLOGY, Issue 5 2001V. Silberschneider The number of glass eels Anguilla australis and A. reinhardtii caught in artificial habitat collectors, made from a PVC base and polyethylene split rope fibres, was related to the number of rope fibre tufts attached to each collector rather than collector area directly. Ageing of collectors in situ to promote algal growth enhanced the catch of glass eels. Glass eels entered the collectors at night primarily during the flood tide, and did not move into the collectors during daylight hours. Glass eel abundance increased with increasing distance from the freshwater drain located in the causeway. The artificial habitat collectors are effective for assessing relative numbers of resettling glass eels and may be useful for studying recruitment and settlement patterns of other anguillid eel species, as well as identifying areas and habitats within a catchment that provide important shelter for glass eels. Sampling glass eels can be carried out with maximum effect and minimum effort using compact, aged artificial habitat collectors on the night time flood tide when low tide coincides with dusk. [source] Silicon drain with channels along the sides for internal biliary stenting of hepaticojejunostomy in hepatic hilar malignanciesJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 5 2009Hiroshi Yoshida Abstract Background:, We compared two types of stents in patients who underwent surgery for hepatic hilar malignancies. Methods:, Twenty-one patients with hepatic hilar malignancies who underwent hepatectomy were randomly assigned to one of two groups. A 5-Fr silicon drain with an internal lumen and side holes was used for the hepaticojejunostomy in one group (intraluminal stent group), and a 10-Fr silicon drain with channels along the sides was used in the other (channel stent group). Results:, Leakage developed in four patients (36.4%) in the intraluminal stent group versus two (20.0%) in the channel stent group. Cholangitis developed in three patients with leakage (27.3%) in the intraluminal stent group versus no patient in the channel stent group. After operation, the times required for the serum alkaline phosphatase and total bilirubin levels to return to the normal range were significantly shorter in the channel stent group (5.3 ± 2.9, 3.8 ± 2.2 days) than in the intraluminal stent group (17.0 ± 5.8, 9.4 ± 5.7 days) (P < 0.0001, P = 0.0093). Conclusion:, A 10-Fr silicon drain with channels is superior to a 5-Fr silicon drain with an internal lumen for internal biliary stenting of hepaticojejunostomy in patients with hepatic hilar malignancies. [source] Decline of hepatitis B carrier rate in vaccinated and unvaccinated subjects: Sixteen years after newborn vaccination program in TaiwanJOURNAL OF MEDICAL VIROLOGY, Issue 4 2003Hans Hsienhong Lin Abstract Taiwan was an endemic area for hepatitis B virus (HBV) infection, and related liver diseases cause a significant drain of public resources. To control the endemic, a nation-wide newborn vaccination program was started in 1985. We reviewed the results of the annual survey for HBV surface antigen (HBsAg) performed in freshmen class of two high schools in Hualien, eastern Taiwan, from 1991 to 2001. A total of 10,194 students, most of them 15 years old, were tested for serum HBsAg using enzyme immunoassays. There is a significant trend (P,<,0.0001) of decreasing HBsAg carrier rate from 20.3 to 4.4% in males and 14.3% to 2.4% in females, respectively, over 11 years. The HBsAg carrier rate was 16.0,20.3% in students surveyed during 1991,1993 (born more than 6 years before the start of the national vaccination program), which decreased to 7.7,11.9% during 1994,1999 (born 1,6 years before the program). It further declined to 4.7% and 3.4% in 2000 and 2001 (born after the start of the program). The HBsAg carrier rate in male students was significantly higher than that in female students in most of the years. The HBV newborn vaccination program not only successfully prevented most of the perinatal transmission of HBV but also reduced horizontal transmission of HBV to children born up to 6 years before the start of the program. Also, the protection persisted for at least 15 years. J. Med. Virol. 69:471,474, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||