Patterns and Rates of Land Use Land Cover Change: A Case Study of Ambos Nogales (Arizona and Sonora), 1985-2004

Abstract The continued expansion of the paired U.S.–Mexican border cities of Ambos Nogales presents many environmental management and urban planning challenges. This study focuses on a comparative study of spatial patterns and rates of land-use and land-cover change, in relation to land degradation, deforestation, and urban growth over different time periods. Based on historical data the study suggests that both cities have experi- enced high land degradation; however, land on the Arizona-side has been more stable and less degraded. However, there were more severely degraded areas found in Nogales, Arizona, than in Nogales, Sonora. The delineation of land use change and the severity of land degradation provide important information to planners about areas that should be targeted for development and other areas that require restoration to natural settings. Keywords: Nogales, land use land cover, urban growth, land degradation Resumen La expansión continua de las ciudades gemelas de Ambos Nogales (USA-Mexico) presenta muchos desafíos de planificación urbana y manejo ambiental. Este estudio se concentra en un análisis comparativo de los patrones espaciales y velocidad de cambios de uso del suelo con relación a la degradación del terreno, deforestación, y crecimiento urbano durante distintos períodos de tiempo. Basado en datos históricos el estudio sugiere que ambas ciudades han experimentado alta degradación de tierra, pero la tierra en el lado de Arizona ha sido más estable y menos degradada. Sin embargo, en Nogales Arizona, habían áreas severamente más degradadas que en Nogales, Sonora. Palabras clave: Nogales, crecimiento urbano, uso de suelo, degradación de tierra

Prevalence of multidrug resistance Campylobacter jejuni and Campylobacter coli in chickens slaughtered in selected markets, Malaysia

The objectives of this study were to determine the occurrence of Campylobacter spp. in live chickens sold at wet markets in Selangor, Malaysia and the multidrug resistance (MDR) profiles of the isolates. Cloacal swabs were taken from the chickens before slaughter and their caecal mucosae were swabbed after slaughter. Of the 90 chickens examined, 68 (75.6%) were positive for Campylobacter. Campylobacter were recovered from caecal swabs (53/90) and cloacal swabs (34/90) and Campylobacter coli (46 isolates) were identified slightly more than Campylobacter jejuni (41 isolates), but these differences were not significant (p<0.05). The most frequently observed resistance was to cephalothin (95.5%), followed by tetracycline (80.8%), erythromycin (51.4%), enrofloxacin (42.4%) and gentamicin (24.4%). Multidrug resistance (resistant to four or more antibiotics) was detected in 35.3% isolates. Campylobacter jejuni showed nine resistance profiles and the most common was to gentamicin-eryhtromycin-enrofloxacin-cephalothin-tetracycline (32.4%) combination while C. coli showed six profiles, with cephalothin-tetracycline (32.2%) combination being most common

Ultrafiltration Membrane Process for Pyrogen Removal in the Preparation of Water for Injection (WFI)

An artificial kidney process based on ultrafiltration (called hemodiafiltration) more effectively removes blood toxins, particularly those of higher molecular weight, than conventional dialysis. In hemodiafiltration, replacement liquid must be added directly to the patient\u27s blood to replace liquid filtered out of the blood in the ultrafiltration cartridge. This replacement liquid is made up of\u27 water for injection (WFI) and other components such as salts and glucose. WFI is produced either by distillation or reverse osmosis and has a cost of $1.00 per liter. A patient with kidney problems would require three hemodiafiltration treatments per week, each requiring 70-80 liters of WFI. Since the target cost of a treatment is less than$100, the cost of WFI alone, $70-$80, makes the process not economically feasible. In order for the hemodiafiltration process to be widely used and to be affordable in third world countries, a system that produces WFI at a low cost is needed. A process to replace distillation or reverse osmosis must be capable of removing pyrogens. Some information is available in the literature indicating that ultrafiltration membranes can remove endotoxins, the main constituent of pyrogens; however, no studies have been done to establish the type of ultrafiltration membrane that gives optimal removal of endotoxins. Ultrafiltration is known to be a much less expensive process than distillation or reverse osmosis. It is thoroughly estimated that WFI produced by Ultrafiltration System would cost only 25 cents per liter. The purpose of this experimental work is to determine the type of ultrafiltration membrane that effectively removes endotoxins with an efficient flow rate. Regenerated cellulose and polyethersulfone membranes with various molecular-weight-cut-offs were evaluated to determine the endotoxin rejection and flux rates of the membranes. A stirred cell experiment was performed as a short-term test, using disc membranes with a diameter of 76 mm and three types of feed solutions. The Limulus Amebocyte Lysate (LAL) Gel Clot test was performed to measure the concentration of pyrogen in the filtrates. The best candidate from the stirred cell experiment was tested in a Hollow Fiber Cartridge Ultrafiltration System over a longer time period. The results showed that a polyethersulfone membrane with a molecular-weight-cut-off (MWCO) of 10,000 rejected endotoxin to below the US Pharmacopeia ( USP) limit of endotoxin content, 0.25 EU/ml, with the best flux rate. Since polyethersulfone membranes were not available in a cartridge form, the membrane with the closest molecular structure, a polysulfone membrane, was tested in a Hollow Fiber Cartridge Ultrafiltration System. The results showed that the polysulfone membrane cartridge rejected endotoxin content from 625 EU/ml to less than 0.25 EU/ml consistently over a week-long test period. In addition, the flux rate remained constant at 129 L/m2 /hr. Thus, the polysulfone membrane of 10,000 MWCO can be used in an ultrafiltration system to produce Water for Injection (WFI)