Effects of the antimicrobial agent sulfamethazine on metolachlor persistence and sorption in soil

Recent monitoring investigations have shown that antimicrobial agents used in veterinary medicine can cause non-point source contamination of soils through manure spreading. In the present study, the effect of the antimicrobial agent sulfamethazine (sulfadimidine) on degradation and sorption of the herbicide metolachlor in a sandy loam soil was studied. In soil samples treated with sulfamethazine at two concentrations (15 and 150 microg kg(-1) soil), metolachlor persistence was not different than of that observed in untreated samples. These results were supported by the absence of effects of both sulfamethazine concentration levels on the size of the culturable soil bacteria population. Equilibrating soil samples with metolachlor solutions containing equivalent sulfamethazine concentrations did not lead to any significant effects on metolachlor sorption, suggesting that, under the conditions of the present experiment, sulfamethazine did not affect metolachlor bioavailability in soil. This laboratory investigation showed that concentrations of sulfamethazine in the microg kg(-1) range did not cause significant effects on metolachlor degradation and sorption thus not affecting the main processes ruling its environmental fate in soil.     

Larval salivary glands are a source of primer and releaser pheromone in honey bee (Apis mellifera L.)

A brood pheromone identified in honeybee larvae has primer and releaser pheromone effects on adult bees. Using gas chromatography–mass spectrometry (GC–MS) to evaluate fatty acid esters—the pheromonal compounds—in different parts of the larvae, we have localized the source of the esters as the larval salivary glands. A histochemical study describes the glands and confirms the presence of lipids in the glands. Epithelial cells of the gland likely secrete the fatty acids into the lumen of the gland. These results demonstrate the salivary glands to be a reservoir of esters, components of brood pheromone, in honeybee larvae.     

Performance evaluation of biodiesel from used domestic waste oils: A review

Global warming, high-energy demand and availability of new technologies are among the factors catalyzing the search for alternative sources of energy. Currently, there is renewed interest in obtaining energy from wastes hitherto meant for disposal. Increased costs of disposal and their attendant problems of heavy environmental loading are some aspects making the disposal option unattractive. These wastes are sources of energy and among the several sources of generating this energy are the waste-to-energy (WTE) categories with potentials for useable fuel production. The WTE materials are mainly used domestic waste oils (UDWOs), municipal solid waste (MSW), agricultural and industrial wastes. However, the latter wastes are not attractive as they consist of innumerable hazardous contaminants. The UDWOs are arguably a safe and cost effective source of useable fuel. Their conversion offers the merits of a reduction in greenhouse gas emission (GHG), enhancing fuel diversification and a qualitatively comparable energy output to fossil diesel fuels. Thus, UDWOs could significantly contribute towards achieving the 2020 and 2030 goals of substituting approximately 20% and 30% of petro-diesel with biofuels in US and EU, respectively. Moreover, attaining the forecasted annual production rate of 227 billion liters of biofuel by most active stakeholders in the biodiesel industry could be easily achieved.This review aims to analyze the performance of biodiesel fuels obtained from UDWO and to demonstrate the suitability of applying these fuels as substitutes to mineral diesel in various industries. Benefits of UDWO as a biodiesel feedstock were as well highlighted.     

Development of prolonged standing strain index to quantify risk levels of standing jobs

Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness. multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.     

Converting Waste Polystyrene into Adsorbent: Potential Use in the Removal of Lead and Cadmium Ions from Aqueous Solution

Waste of polystyrene was converted into a cation exchange resin and was used for the removal of lead and cadmium metals from aqueous solution. Wastes consisting of coffee cups were crushed into small pieces and immersed into a solution of sulfuric acid in order to attach sulfonic group to polymer chain, these groups are responsible for the exchange properties of the modified plastic. The cation exchange capacity (CEC) was determined and was comparable to commercial exchangers. The adsorption isotherms of resin with synthetic wastewater containing lead and cadmium ions were tested. Adsorption analysis results obtained at various concentrations showed that the adsorption pattern on the resin followed Langmuir isotherms.     

Refugee perceptions of the quality of healthcare: findings from a participatory assessment in Ngara, Tanzania

This article describes the findings of a participatory assessment of Burundian and Rwandan refugees' perceptions of the quality of health services in camps in Ngara, Tanzania. Taking a beneficiary-centred approach, it examines a collaborative effort by several agencies to develop a generic field guide to analyse refugees' views of healthcare services. The objective was to gather information that would contribute to significant improvements in the care offered in the camps. Although the primary focus was on healthcare, several broader questions considered other general apprehensions that might influence the way refugees perceive their healthcare. Findings indicated that while refugees in Ngara were generally satisfied with the quality of healthcare provided and healthcare promotion activities, recognition of some key refugee concerns would assist healthcare providers in enhancing services. With increasing need for refugee community participation in evaluating humanitarian assistance, this assessment has relevance both in the context of Ngara and beyond.     

Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Sorbents synthesized from various types of ash (coal fly ash, coal bottom ash, oil palm ash, and incinerator ash) for flue gas desulfurization were investigated. The sorbents were prepared by mixing the ashes with calcium oxide and calcium sulfate using the water hydration method. The effects of various sorbent preparation variables, such as the hydration period, the ratio of calcium oxide to ash, and the amount of calcium sulfate, on the Brunauer-Emmett-Teller (BET)-specific surface area of the resulting sorbent were studied using a two-level full factorial design. The surface area of the sorbents obtained range from 15.4 to 122.1m²/g. Regression models were developed to correlate the significant variables to the surface area of the sorbents. An analysis of variance (ANOVA) showed that the model was significant at a confidence level of 95%. It was found that apart from all the individual variables studied, interactions between variables also exerted a significant influence on the surface area of the sorbent. From the activity test results, it was found that sorbents prepared from coal fly ash and oil palm ash have the highest SO₂ absorption capacity. Scanning electron microscope (SEM) analysis showed that the sorbent was composed of a compound with a high structural porosity, while an X-ray diffraction spectrum showed that calcium aluminum silicate hydrate compounds are the main products of the hydration reaction.     

Analysis of driver injury severity levels at multiple locations using ordered probit models

Problem: The occurrence and outcome of traffic crashes have long been recognized as complex events involving interactions between many factors, including the roadway, driver, traffic characteristics, and the environment. This study is concerned with the outcome of the crash. Method: Driver injury severity levels are analyzed using the ordered probit modeling methodology. Models were developed for roadway sections, signalized intersections, and toll plazas in Central Florida. All models showed the significance of driver's age, gender, seat belt use, point of impact, speed, and vehicle type on the injury severity level. Other variables were found significant only in specific cases. Results: A driver's violation was significant in the case of signalized intersections. Alcohol, lighting conditions, and the existence of a horizontal curve affected the likelihood of injuries in the roadway sections' model. A variable specific to toll plazas, vehicles equipped with Electronic Toll Collection (ETC), had a positive effect on the probability of higher injury severity at toll plazas. Other variables that entered into some of the models were weather condition, area type, and some interaction factors. This study illustrates the similarities and the differences in the factors that affect injury severity between different locations.     

Effect of grazing on plant attributes and hydrological properties in the sloping lands of the East African highlands

Extending livestock grazing to the steep slopes has led to unstable grazing systems in the East African Highlands, and new solutions and approaches are needed to ameliorate the current situation. This work was aimed at studying the effect of livestock grazing on plant attributes and hydrological properties. The study was conducted from 1996 to 2000 at the International Livestock Research Institute at Debre Ziet Research Station. Two sites were selected: one at 0–4% slope, and the other at 4–8% slope. The treatments were: (1) no grazing (control); (2) light grazing, 0.6 animal unit months per hectare (aum/ha); (3) moderate grazing, 1.8 aum/ha; (4) heavy grazing, 3.0 aum/ha; (5) very heavy grazing, 4.2 aum/ha; (6) initially plowed and continuously very heavily grazed, 4.2 aum/ha. The result showed that species richness, infiltration rate, bare ground, and soil loss significantly varied with grazing pressure. Species richness was higher in grazed plots compared to nongrazed plots. Biomass yield improved on heavily grazed plots as cow dung accumulated over years. Cynodon dactylon plant species persisted with livestock grazing pressure in both sites. Infiltration rate improved and soil erosion declined in all treatments after the first year.     

Multiple regression analysis of the sources of variation in orientation of two sympatric sandhoppers, <Emphasis Type="Italic">Talitrus saltator</Emphasis> and <Emphasis Type="Italic">Talorchestia brito</Emphasis>, from an exposed Mediterranean beach

Two sympatric species from an exposed sandy beach in north-western Tunisia, the sandhoppers Talitrus saltator (Montagu) and Talorchestia brito Stebbing, were compared as regards orientation under natural conditions. Sets of experiments were carried out on the beach using two experimental arenas, one permitting the view of both the sky and landscape and the other of the sky only. Replicates were made at different hours of the day, in different days and period of the year and with various climatic conditions. Multiple regression models were fitted to the angular data obtained. These models allow an estimate of the trends of variation depending on a combination of factors. The simultaneous effects of environmental factors influencing orientation were quantified for each species. The sun was confirmed as the major orientation cue in these populations, but the concentration of directional choices was enhanced by the landscape vision. The climatic factors affected orientation in different ways depending on the time of day and year. When the two species were compared, Talitrus saltator showed a higher flexibility of response than Talorchestia brito under the same environmental conditions, supporting the hypothesis of a higher level of terrestrialization of the former species.