A monolithic photovoltaic-photoelectrochemical device for hydrogen production via water splitting

Direct water electrolysis was achieved with a novel, integrated, monolithic photoelectrochemical-photovoltaic design. This photoelectrochemical cell, which is voltage biased with an integrated photovoltaic device, splits water directly upon illumination; light is the only energy input. The hydrogen production efficiency of this system, based on the short-circuit current and the lower heating value of hydrogen, is 12.4 percent.     

Impact of farm management on expression of early mortality syndrome/acute hepatopancreatic necrosis disease (EMS/AHPND) on penaeid shrimp farms in Thailand

Asian shrimp farming industry has experienced massive production losses due to a disease caused by toxins of Vibrio bacteria, known as early mortality syndrome/acute hepatopancreatic necrosis disease (EMS/AHPND) for the last 5 years. The disease can cause up to 100% cumulative pond mortality within a week. The objective of this study was to identify factors associated with AHPND occurrence on shrimp farms. A case–control study was carried out on shrimp farms in four provinces of Thailand. Factors related to farm characteristics, farm management, pond and water preparation, feed management, post‐larvae (PL) shrimp and stock management were evaluated. Multivariable logistic regression analysis identified factors affecting AHPND occurrence at the pond level. Chlorine treatment, reservoir availability, use of predator fish in the water preparation, culture of multiple shrimp species in one farm and increased PL stocking density contributed to an increased risk of AHPND infection, while delayed first day of feeding, polyculture and water ageing were likely to promote outbreak protection. Additionally, the source of PL was found to be associated with AHPND occurrence in shrimp ponds, which requires further study at the hatchery level. Identification of these factors will facilitate the development of effective control strategies for AHPND on shrimp farms.     

Determining the disaggregated economic value of irrigation water in the Musi sub-basin in India

In this paper the residual method is used to determine the disaggregated economic value of irrigation water used in agriculture across crops, zones and seasons. This method relies on the belief that the value of a good (its price by its quantity) is equal to the summation of the quantity of each input multiplied by its average value. By applying this method to the Musi sub-basin; a subdivision of the Krishna basin in India, it was found that the value of irrigation water use is not equated across the crops, zones and seasons. The reasons why there is no sinlge value of irrigation water use are suggested. As farmers do not have perfect knowledge, do not all possess the same resource base, plant different crops for a variety of reasons (some for a financial return on land instead of water and others for sustenance), possess different crop rotation practices and are possibly riks adverse, they all value water differently. However, the results need to be interpreted with care as the crop with the lowest return to water is probably not the one to be sacrificed if water is restricted, since farmers plant crops for a variety of reasons (and sometimes not for the highest return to water that they can achieve).     

Effects of Soil Type and Cover Condition on Cryptosporidium parvum Transport in Overland Flow

Overland transport kinetics of pathogens is controlled, in large part, by soil and vegetation. With an increasing number of concentrated animal operations, there is becoming a greater need to dispose of a vast amount of manure in a single, localized area. Animal manure contains a substantial amount of microbial pathogens, including Cryptosporidium parvum that may pose a threat of contamination of water resources. This study examines the kinetics of C. parvum in overland transport and critical factors involved in the design of best management practices, especially vegetative filter strips, to prevent the transport of harmful pathogens to water bodies. Three soil types were tested (Catlin silt-loam, Alvin fine sandy-loam, Darwin silty-clay), spanning the entire spectrum of typical Illinois soils. A 20-min rainfall event was produced using a small-scale (1.07 m?×?0.66 m) laboratory rainfall simulator over a soil box measuring 0.67 m?×?0.33 m. Each soil type was tested for pathogen transport kinetics with bare surface conditions as well as with smooth brome and fescue vegetative covers. Surface runoff, soil cores, and near-surface runoff were each analyzed for infective C. parvum oocysts using cell culture infectivity assays. Results showed that vegetation greatly reduced the recovery of infective oocysts, in addition to delaying the time to the peak recovery. However, there was no clear evidence of any one vegetation type being advantageous over another. The bare soil experiments resulted in a higher recovery of C. parvum oocysts from the Darwin soil compared to other two soils. Analyses of soil cores show a slightly higher recovery of oocysts in the Catlin soil compared to Alvin or Darwin soils.     

Urodynamic effects of a percutaneously controlled static hydraulic urethral sphincter in canine cadavers

OBJECTIVE: To describe a percutaneously controlled static hydraulic urethral sphincter (SHUS) and evaluate urodynamic effects of the SHUS in canine cadavers. SAMPLE POPULATION: Cadavers of 6 adult female dogs. PROCEDURE: Cadavers were obtained immediately after dogs were euthanatized. Baseline maximal urethral closure pressure (MUCP) and cystourethral leak point pressure (CLPP) were measured by use of a urethral pressure profilometer. An SHUS system was constructed by use of a silicone vascular occluder and subcutaneous infusion port. The SHUS system was then placed around the pelvic urethra in each cadaver. Measurements of MUCP and CLPP were repeated after varying occlusion of the SHUS (0%, 25%, and 50% occlusion). Baseline MUCP and CLPP values were compared with values obtained at 0%, 25%, and 50% occlusion of the SHUS by use of repeated-measures ANOVA. RESULTS: Mean +/- SD MUCP for canine cadavers was 7 +/- 1.3 cm H2O at baseline, which increased to 127 +/- 53 cm H2O after 50% occlusion of the SHUS. Mean CLPP was 11 +/- 8.6 cm H2O at baseline, which increased to 73 +/- 38 cm H2O after 50% occlusion of the SHUS. Mean MUCP and CLPP were significantly associated with the amount of occlusion. CONCLUSIONS AND CLINICAL RELEVANCE: The SHUS had positive effects on MUCP and CLPP in canine cadavers. Therefore, additional evaluation of the SHUS in live dogs is warranted.