895 resultados para Cut-bank sediment


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Field and laboratory observations have shown that a relatively low beach groundwater table enhances beach accretion. These observations have led to the beach dewatering technique (artificially lowering the beach water table) for combating beach erosion. Here we present a process-based numerical model that simulates the interacting wave motion on the beach. coastal groundwater flow, swash sediment transport and beach profile changes. Results of model simulations demonstrate that the model replicates accretionary effects of a low beach water table on beach profile changes and has the potential to become a tool for assessing the effectiveness of beach dewatering systems. (C) 2002 Elsevier Science Ltd. All rights reserved.

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On the basis of a spatially distributed sediment budget across a large basin, costs of achieving certain sediment reduction targets in rivers were estimated. A range of investment prioritization scenarios were tested to identify the most cost-effective strategy to control suspended sediment loads. The scenarios were based on successively introducing more information from the sediment budget. The relationship between spatial heterogeneity of contributing sediment sources on cost effectiveness of prioritization was investigated. Cost effectiveness was shown to increase with sequential introduction of sediment budget terms. The solution which most decreased cost was achieved by including spatial information linking sediment sources to the downstream target location. This solution produced cost curves similar to those derived using a genetic algorithm formulation. Appropriate investment prioritization can offer large cost savings because the magnitude of the costs can vary by several times depending on what type of erosion source or sediment delivery mechanism is targeted. Target settings which only consider the erosion source rates can potentially result in spending more money than random management intervention for achieving downstream targets. Coherent spatial patterns of contributing sediment emerge from the budget model and its many inputs. The heterogeneity in these patterns can be summarized in a succinct form. This summary was shown to be consistent with the cost difference between local and regional prioritization for three of four test catchments. To explain the effect for the fourth catchment, the detail of the individual sediment sources needed to be taken into account.

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A number of contemporary studies rightly emphasize the notion that policy outcomes result from institutional determinants. But as a growing literature on institutional development notes, these institutions are themselves impermanent. Sometimes, in crisis moments, institutions are replaced wholesale. More frequently, institutions evolve gradually over time. Using the Brazilian Central Bank as a case study, this article illustrates that the policy-making process itself can be a central driver of gradual institutional development, with institutions evolving through the accumulation of policy choices made over many years and under different policymakers in response to contemporaneous events and unforeseeable economic and political challenges.

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The effect of sheep digestion and mastication on Malva parviflora L. seed transmission, viability and germination was investigated. Mature M. parviflora seeds were subjected to 2 seed treatments: 'scarified', where the hard seed coat was manually cut to allow inhibition, and 'unscarified', where the hard seed coat was not cut. Seeds were placed directly into the rumen of fistulated sheep and removed at 0, 12, 24, 36 and 48 h of rumen digestion. After 12 h of in sacco exposure to digestion in the rumen, the germination of seeds that were initially scarified dropped from 99.2 to 1.4% and longer exposure periods produced no germinable seeds. In contrast, seeds that were unscarified when placed in the rumen produced over 92% germination regardless of in sacco digestion time, although manual scarification after retrieval was essential to elicit germination. In a second experiment, unscarified seeds (29000) were fed in a single meal to fistulated sheep and feces were collected at regular intervals between 6 and 120 h after feeding. Fecal subsamples were taken to determine number of seeds excreted, seed germination on agar and seed germination from feces. Major seed excretion in the feces commenced after 12 h and continued until 144 h, with peaks between 36 and 72 h after consumption. Although mastication and gut passage killed the majority of unscarified seeds, about 20% were recovered intact and over 90% of these recovered seeds were viable and could, thus, potentially form an extensive seed bank. A few excreted seeds (1%) were able to germinate directly from feces, which increased to a maximum of 10% after subsequent dry summer storage (3 months). Through information gained in this study, there is a potential to utilise livestock in an integrated weed management program for the control of M. parviflora, provided additional measures of weed control are in place such as holding periods (> 7 days) for movement of livestock from weed infested areas.

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BACKGROUND: Persons with human immunodeficiency virus (HIV) risk behaviors are excluded from donation to reduce the risk of transfusion-transmitted infection. Persons donating to be tested for HIV may therefore deny risk behaviors. STUDY DESIGN AND METHODS: A random sample of donors completed a survey on motivations, knowledge, and attitudes on the screening process. Donors were considered test seekers if they agreed with two statements ""I think that blood donation is a good, fast, and anonymous way to get my blood tested"" and ""I donate to get my test results."" This study was conducted from June to November 2006 at the largest blood bank in Sao Paulo, Brazil. RESULTS: Of 3061 participants, 208 (7%) were test seekers. They tended to be male and had a lower educational level. They were more likely to have incorrect knowledge about blood safety (e.g., not knowing that a unit can test antibody negative and still transmit infection, 60% vs. 42%, p = 0.02), express dissatisfaction with screening questions (e.g., feeling that important questions were not asked, 14% vs. 5%, p < 0.01), and concur that donors do not answer questions truthfully (e.g., donors have more sexual partners than they admit, 29% vs. 18%, p < 0.01). Test seekers were more likely to believe that it is acceptable to donate blood to get tested for HIV (41% vs. 10%, p < 0.01). CONCLUSIONS: Test-seeking motivation, coupled with low knowledge of window period risk, is counter to improving blood safety and to donor prevention needs. Donor education needs to be improved along with availability of appropriate HIV counseling and testing.

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OBJECTIVES To describe the use of pulsed fluoroscopic guidance, to perform endoscopic procedures in pregnant women, by inverting the fluoroscope`s c-arm using a lead thyroid collar to shield the fetus from the direct X-ray beam. The use of radiation during treatment of pregnant patients with urolithiasis remains a recurring dilemma. METHODS Between May 2006 and December 2008, endoscopic treatment due to ureteral stones was attempted in 8 pregnant women. In all cases, we use an inverted fluoroscope`s c-arm during endoscopic treatment associated with 2 lead neck thyroid collars to shield the uterus, protecting the fetus from direct radiation. Indication for treatment was symptomatic ureteral stones unresponsive to medical treatment in 7 and persistent fever in 1. RESULTS Mean ureteral stone size was 8.1 +/- 4.8 mm, located in the left ureter in 5 (62.5%) cases. Three (37.5%) patients had stone located in the upper ureter, 2 (25%) in the middle ureter, and 3 (37.5) in the distal ureter. In 6 cases, ureteral stones were treated using the semi-rigid ureteroscope, whereas in 1 case a flexible ureteroscope was needed. One woman was treated with insertion of a double-J stent due to associated urinary infection. No women has early delivery related to the endoscopic procedure, and all neonates were perfectly normal. CONCLUSIONS We present a technique for endoscopic procedures in pregnant women inverting the fluoroscope`s c-arm and protecting the fetus from the direct X-ray beam. This practical approach should be specially considered when no portable ultrasound and radiologic assistance in available in the operating room. UROLOGY 75: 1505-1508, 2010. (c) 2010 Published by Elsevier Inc.

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A polyclonal antibody (C4), raised against the head domain of chicken myosin Va, reacted strongly towards a 65 kDa polypeptide (p65) on Western blots of extracts from squid optic lobes but did not recognize the heavy chain of squid myosin V. This peptide was not recognized by other myosin Va antibodies, nor by an antibody specific for squid myosin V. In an attempt to identify it, p65 was purified from optic lobes of Loligo plei by cationic exchange and reverse phase chromatography. Several peptide sequences were obtained by mass spectroscopy from p65 cut from sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) gels. BLAST analysis and partial matching with expressed sequence tags (ESTs) from a Loligo pealei data bank indicated that p65 contains consensus signatures for the heterogeneous nuclear ribonucleoprotein (hnRNP) A/B family of RNA-binding proteins. Centrifugation of post mitochondrial extracts from optic lobes on sucrose gradients after treatment with RNase gave biochemical evidence that p65 associates with cytoplasmic RNP complexes in an RNA-dependent manner. Immunohistochemistry and immunofluorescence studies using the C4 antibody showed partial co-labeling with an antibody against squid synaptotagmin in bands within the outer plexiform layer of the optic lobes and at the presynaptic zone of the stellate ganglion. Also, punctate labeling by the C4 antibody was observed within isolated optic lobe synaptosomes. The data indicate that p65 is a novel RNA-binding protein located to the presynaptic terminal within squid neurons and may have a role in synaptic localization of RNA and its translation or processing. (C) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

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Aim: To demonstrate that the evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens (LMLC) is useful to identify patients with a haematuria of glomerular or non-glomerular origin. Methods: A comparative double-blind study between phase contrast microscopy (PCM) and LMLC is reported to evaluate the efficacy of these techniques. Urine samples of 39 patients followed up for 9 months were analyzed, and classified as glomerular and non-glomerular haematuria. The different microscopic techniques were compared using receiver-operator curve (ROC) analysis and area under curve (AUC). Reproducibility was assessed by coefficient of variation (CV). Results: Specific cut-offs were set for each method according to their best rate of specificity and sensitivity as follows: 30% for phase contrast microscopy and 40% for standard LMLC, reaching in the first method the rate of 95% and 100% of sensitivity and specificity, respectively, and in the second method the rate of 90% and 100% of sensitivity and specificity, respectively. In ROC analysis, AUC for PCM was 0.99 and AUC for LMLC was 0.96. The CV was very similar in glomerular haematuria group for PCM (35%) and LMLC (35.3%). Conclusion: LMLC proved to be effective in contributing to the direction of investigation of haematuria, toward the nephrological or urological side. This method can substitute PCM when this equipment is not available.

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Deforestation in southeast Brazil has led to the extinction of Hymenaea courbaril var. stilbocarpa and ex situ conservation has been established. In this study, the levels of genetic diversity and the effective population size of H. courbaril in a germplasm bank were investigated using six nuclear microsatellite loci. A total of 79 and 91 alleles were found in 65 seed-trees and their 176 offspring, respectively. Offspring have a higher average number of alleles per locus (A = 15.2) than seed-trees (A = 13.2), but lower observed heterozygosity (offspring: H (o) = 0.566; seed-trees: H (o) = 0.607). The estimate of outcrossing rate shows that the study population is perfectly outcrossed (t (m) = 0.978, P > 0.05). Significant deviations from random mating were detected through mating among relatives and correlated matings. The average variance in effective population size for each family was 2.63, with a total effective population size retained in the bank of 170.1. These results confirm that the preserved population of H. courbaril retains substantial genetic variability.