361 research outputs found
Bactriological quality of rainwater samples in cisterns in rural areas of Gomishan
Background and purpose: Due to inadequate quantity and low quality of water resources in rural regions of Gomishan (Golestan province), local residents use cisterns for household water. Therefore, it is necessary to investigate the hygienic situation of these cisterns. Materials and methods: In this study, water samples were obtained from 31 villages using random sampling (two times; total number of samples=406). Bacteriological tests were carried out by standard methods. The relationship between hygienic situation of cisterns and bacteriological quality of water were statistically analyzed. Results: A total of 406 water samples was examined by measuring total coliform and fecal coliform, in which. 94 samples (23.14) showed total coliform and 28 sample (6.89) showed fecal coliform. A significant relationship was observed between hygienic status of cisterns and bacteriological pollution (P<0.05). Conclusion: Microbial contamination in the studied cisterns calls for sanitizing the cistern in the region and changing the drinking water resources. © 2016, Mazandaran University of Medical Sciences. All rights reserved
Comparison of photocatalytic systems including silver and titanium dioxide nanoparticles efficiencies for the E. coli removal from drinking water
The removal and destruction of organic contaminants in groundwater can be addressed through the impregnation of adsorbents with photoactive catalysts. In this paper removal trend of E. coli from drinking water examined by nano silver and nano titanium dioxide. To perform this, four different concentration of silver nano particles and titanium dioxide under UV radiation (with 247 nm- wavelength) used. The results showed the nano particles of silver and titanium reach to 100% disinfection efficiency at the concentrations of 0.4 mg/l (with 20 minutes contact time) and 0.8 mg/l (with 40 minutes contact time), respectively. For equal amounts of disinfectant and equal number of E. coli colonies in drinking water, disinfection potential for (nAg + V) is significantly higher than (nTiO2 + UV). When the nano particles concentration increases, the disinfection rate rises, and it was higher and faster done by the nano silver particles comparing to nano-titanium particles (Pvalue < 0.05, R²= 0.705)
Water disinfection using photocatalytic process with titanium dioxide nanoparticles
Background and purpose: Disinfection is one of the most important stages in water treatment. So far, various chemical disinfection methods such as chlorination have been widely used. However, these methods have serious disadvantages, like producing DBPs. The purpose of this research was to study the efficacy of nTiO2 photocatalyst process on removing E.Coli as a water microbial pollution index and effects of some parameters on its efficiency. Materials and methods: Water was artificially contaminated with E.Coli. Culture method and counting were performed according to standard methods for water and wastewater and was reported as CFU/ml. The size of nTiO2 was 20 nm that was used in the presence or absence of UV for disinfection. The Kolmogorov-Smirnov Test was used to check the normality of the data. The ANOVA and T-Test were used for analyzing the data. Results: The results indicated that the inactivation of Escherichia coli increased with increase of nTiO2 catalyst dose and contact time. However, the efficiency decreased when the number of colonies increased. Minimum, average and maximum percentage removal of nTiO2+UV process were 75.1, 88.9±12.7, and 100%, respectively, in 40 min contact time and 0.8 g/L catalyst dose. Conclusion: The bacteria mortality rate in the presence of UV alone was more than that of the nTiO2 alone process. However, the efficiency of the photocatalytic process (UV+nTiO2) was more than that of the UV alone or nTiO2 alone. © 2015, Mazandaran University of Medical Sciences. All rights reserved
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A review of research on the growth of multinational enterprises: a Penrosean lens
We provide a comprehensive review of the growth of multinational enterprises (MNEs) based on a quarter-century (25 years) of scholarly international business publications. We synthesize research insights on the determinants of the growth of MNEs through the lens of Penrose’s theory of firm growth, which is the most influential theoretical perspective on firm growth. The review takes stock of the research findings on the facilitators, constraints, and the trajectory of growth of MNEs, and elaborates on the commonalities and differences between research on the growth of MNEs that draws on Penrose’s theory and research that does not. This comparison highlights the opportunity to build an internally coherent theory of the growth of MNEs, that is, a theory that connects ‘what an MNE is’ to ‘what determines an MNE’s growth.’ It also indicates that past research placed a strong emphasis on exogenous factors (e.g., cross-country distances) as key constraints on growth even though the Penrosean lens suggests a close consideration of endogenous factors that drive international growth, as well as endogenizing the ostensibly exogenous growth determinants. The review highlights the importance of firm-specific managerial knowledge and learning, which shapes the direction of the growth of MNEs and ensures its administrative coherence
An assessment the effect of Fructo-oligosaccharide on growth performance, survival and hematological factors in sturgeon juvenile (Acipenser sttellatus)
The purpose of this study was to evaluate the effect of Fructo-oligosaccharide (FOS) on growth and survival performances of sturgeon juvenile fish (Acipenser stellatus). 90 sturgeon fry fishes (average weight 30.16±0/14 gram) has been brought from Sturgeon International, Research Institute and stored in fiberglass tanks using randomize design with 3 treatments each with 3 replicates in relative constant physico-chemical water parameters(P>0.05) then fed with basal adaptive food for two weeks. Fry fed 11 weeks with diets containing 0% (Basal food), 1% and 2% oligofructose (Raftilose p95, Sigma Co.) added to the basal food. The results revealed that 1% pribiotic compare to other treatments caused increasing weight gain, specific growth rate, feed conversion, feed efficiency, protein efficiency ratio and liver indices significantly (p 0.05). At the end of experiment, after bleeding from sample fries, the hematological characters showed that there are no any differences between hemoglobin, WBC and RBC numbers, hematocrit, MCV, MCH and MCHC between treatments(P>0.05) although the number of WBC in 1% and numbers of neutrophils in 1 and 2% prebiotic had differences with zero% significantly (P< 0.05). Based on these results good influence on the improving growth and feeding performances by oligofroctose as prebiotic was proved in Acipenser stellatus fries and 1% level was the best
Leukemia in Iran: Epidemiology and morphology trends
Background: Leukemia accounts for 8 of total cancer cases and involves all age groups with different prevalence and incidence rates in Iran and the entire world and causes a significant death toll and heavy expenses for diagnosis and treatment processes. This study was done to evaluate epidemiology and morphology of blood cancer during 2003-2008. Materials and Methods: This cross- sectional study was carried out based on re-analysis of the Cancer Registry Center report of the Health Deputy in Iran during a 6-year period (2003 - 2008). Statistical analysis for incidence time trends and morphology change percentage was performed with joinpoint regression analysis using the software Joinpoint Regression Program. Results: During the studied years a total of 18,353 hematopoietic and reticuloendothelial system cancers were recorded. Chi square test showed significant difference between sex and morphological types of blood cancer (P-value < 0.001). Joinpoint analysis showed a significant increasing trend for the adjusted standard incidence rate (ASIR) for both sexes (P-value < 0.05). Annual percent changes (APC) for women and men were 18.7 and 19.9, respectively. The most common morphological blood cancers were ALL, ALM, MM and CLL which accounted for 60 of total hematopoietic system cancers. Joinpoint analyze showed a significant decreasing trend for ALM in both sexes (P-value < 0.05). Conclusions: Hematopoietic system cancers in Iran demonstrate an increasing trend for incidence rate and decreasing trend for ALL, ALM and CLL morphology
Drone Fleet Survivability Evaluation Based on Lanchester’s Modified Deterministic Model
An algorithmic approach for the assessment of the survivability is proposed that is based on Lanchester’s modified deterministic model. Methods are suggested for increasing the available time capability for nuclear power plant monitoring and coverage, using the required or a limited number of the operable drones,. Dependencies of the variance between the residual fleet damage and permissible drone fleet damage on monitoring time as well as dependencies of the monitoring time on the recovery group productivity are analysed
Towards a new Synthesis
This paper maintains that the consistent application of subjectivism helps to reconcile contemporary entrepreneurship theory with strategic management research in general, and the resource−based view in particular. The paper synthesizes theoretical insights from Austrian economics and Penrose’s (1959) resources approach, arguing that entrepreneurship is inherently subjective and firm specific. This new synthesis describes how entrepreneurship is manifested in teams, and is driven by both heterogeneity of managerial mental models and shared team experiences
A survey on health status of marine fish in Bandar-e-Imam station
Mariculture is one of the most important sub sector fisheries industry in Asia-pacific region. There are over 40 marine fish species commonly cultured, such as groupers (Epinephlus spp.), snappers (Lutjanus spp.) and Asian sea bass (Lattes calcarifer). But this industry in Southeast Asia experienced serious disease problem since the late 1980s. Khouzestan province has a coastal line about 200 km with many Creek and suitable area for Mariculture. Marine fish culture in Khouzestan province in floating net cages was successfully initiated in Ghazaleh Creek following development of Epinephlus coioides artificial seed production in the 1372. This study has been conducted since 1384 to 1387 in Bandar-e-Imam station. The aim of this research project was to determine the health management status in cage and hatchery, identification of marine fish pathogens (Bacteria, Fungi and parasite), examination of heavy metal in cages sediment and test the physico chemical factors of water in cages and hatchery. Different parts of broodstocks body and fingerlings including intestine, gills and body surface were examined. In this study, 18 Genus and species of bacteria such as Vibrio alginolyticus, Vibrio anguillarum, Vibrio splendidus, Vibrio vulnificus, Plesiomonas shigelloides, Aeromonas hydrophila, Aeromonas caviae, Pseudomonas sp. were diagnosed. Also 7 Genus and species of fungi such as: Aspergillus Niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium sp. And Fusarium sp. Were isolated. In this survey following of disease appearance parasites such as; protozoans Amyloodinium sp. And Trichodina sp. In E.coioides and Acanthopagrus latus and Sparidentex hasta, monogean such as Benedenia sp. In E.coioides and S. hasta, isopoda probably Nerocila sp. In nasal cavity of E.coioides and copepods such as: Caligus sp. And Lernanthropus sp. In A.latus and S.hasta were identified. In this study, microorganisms (bacteria, fungi and parasites) isolated from three different marine fishes species, were reported for the first time in Iran. The range of the physico-chemical parameters of water in cages were: DO (5.42-10.24 ppm), BOD5 (1.51-10.24 ppm), No_2 (0.0197-0.89 ppm), No_3 (3.53-11.93 ppm), Po_4 (0.965-6.05 ppm), turbidity (4-58 NTU) and ammonia (0.0008-0.03 ppm). According to the results parameters such as nitrate, nitrite and turbidity were found more than standard levels. Heavy metals: Ni and Pb relatively high observed
Strong, bold, and kind : Self-control and cooperation in social dilemmas
Financial support from the Swedish Research Council (Vetenskapsrådet), from Formas through the program Human Cooperation to Manage Natural Resources (COMMONS), and the Ideenfonds of the University of Munich is gratefully acknowledged.We develop a model that relates self-control to cooperation patterns in social dilemmas, and we test the model in a laboratory public goods experiment. As predicted, we find a robust association between stronger self-control and higher levels of cooperation, and the association is at its strongest when the decision maker’s risk aversion is low and the cooperation levels of others high. We interpret the pattern as evidence for the notion that individuals may experience an impulse to act in self-interest—and that cooperative behavior benefits from self-control. Free-riders differ from other contributor types only in their tendency not to have identified a self-control conflict in the first place.PostprintPeer reviewe
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