423 research outputs found

    Management of Biesboch reservoirs for quality control with special reference to eutrophication

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    The three Biesbosch Reservoirs are pumped storage reservoirs, fed with rather polluted and highly eutrophic water from the River Meuse. Air injection at the bottom of the reservoirs prevents thermal stratification, which would otherwise result in serious water quality deterioration. Reservoir mixing also serves as an economic algal control measure; mixing over sufficient depth causes light to play the role of limiting factor and this, combined with zooplankton grazing, keeps the biomass of phytoplankton at acceptable levels. Special problems are caused by benthic, geosmin-producing Oscillatoria species growing on the inner embankment. Rooting up the bottom with a harrow is used as the method of control, based on underwater observations by biological staff trained as SCUBA-divers. With regard to pollutant behaviour the three reservoirs act as a series of fully mixed reactors. This enables the application of kinetic models to describe their behaviour and allows the use of a selective intake policy, e.g. for suspended solids with associated contaminants, ammonia and polynuclear aromatic hydrocarbons. A combination of selective intake and self- purification processes - enhanced by the compartmentalisation of the storage volume in three reservoirs - leads to a striking improvement for many water-quality parameters

    Ag Resource Tools & Media Coverage: A Study of Newspaper Coverage of Cotton in Texas

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    Many Extension professionals work with journalists in order to get their message out to various stakeholders. Some develop agricultural resource tools for the media. The study reported here examined coverage of cotton articles from 534 Texas newspapers following the dissemination of the CottonLink© media resource tool. An overall increase was found in the number of articles, newspapers, and circulation size after the dissemination of the CottonLink© media resource tool, while a decrease was found in the number of judgment sentences during the study. Additional research is recommended

    Detecting respiratory bacterial communities of wild dolphins: Implications for animal health

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    Infectious diseases contribute to the vulnerable status of marine mammals, including respiratory illnesses. This study aimed to capture exhaled breath condensate (blow) for microbial identification from wild Indo-Pacific bottlenose dolphins Tursiops aduncus. Individual dolphins were sampled by holding a funnel connected to a 50 ml centrifuge tube over the blowhole of the animal near shore in Shark Bay (SB), Western Australia. Four individuals were sampled on 2 occasions along with seawater samples. Comparative blow and pool water samples were collected from 4 individual common bottlenose dolphins Tursiops truncatus housed in the National Aquarium (NA), Baltimore, Maryland, USA. Bacteria were identified using the V4 region of the 16S rRNA gene from extracted DNA. We identified bacteria independent of seawater in SB dolphins, which included the classes Alphaproteobacteria (26.1%) and Gammaproteobacteria (25.8%); the phyla Bacteroidetes (15.6%) and Fusobacteria (7.2%); and the genera Pseudomonas (11.5%), Pedomicrobium (4.5%), Streptobacillus (3.7%), Phenylobacterium (2.2%) and Sphingomonas (2.1%). There were broad similarities in phyla between SB and NA dolphins yet there were differences between lower taxonomic groups. A number of operational taxonomic units (OTUs) were shared between dolphin individuals, which may be a result of their genetic lineage (siblings or parentage), shared living and social interactions. A number of genera were observed in SB dolphins which have species known to be infectious in marine mammals such as Pseudomonas, Mycoplasma and Streptococcus. This study successfully characterised bacteria from DNA captured in blow from wild dolphins. The ability to capture these communities from individuals in the wild provides a novel health indicator

    Molecular investigation into the presence of a Coxiella sp. in Rhipicephalus sanguineus ticks in Australia

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    Q fever is an infectious disease with a global distribution caused by the intracellular bacterium, Coxiella burnetii, which has been detected in a large number of tick species worldwide, including the brown dog tick, Rhipicephalus sanguineus. Recent reports of a high seroprevalance of C. burnetii in Australian dogs, along with the identification of additional Coxiella species within R. sanguineus ticks, has prompted an investigation into the presence and identification of Coxiella species in R. sanguineus ticks in Australia. Using a combination of C. burnetii species-specific IS1111a transposase gene and Coxiella genus-specific 16S rRNA PCR assays, a Coxiella sp. was identified in 100% (n = 199) of R. sanguineus ticks analysed, and C. burnetii was not detected in any R. sanguineus ticks studied. Phylogenetic analysis of the 16S rRNA gene revealed the Coxiella sequences were closely related to Coxiella sp. identified previously in R. sanguineus and R. turanicus ticks overseas. This study illustrates the value of using genus specific PCR assays to detect previously unreported bacterial species. Furthermore, the presence of an additional Coxiella sp. in Australia requires further investigation into its potential for contributing to serological cross-reactions during Q fever testing

    Fracture of femur: simulation and photoelasticity analysis,”Digest

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    Bones, particularly long ones, are among the most fascinating and intriguing materials, not only because of the complicated structure, but also because of their mechanical behavior, which is still not completely understood.Finite Element computer simulations of the modal behaviour of human femur were compared to experimental results of the resonance frequencies of actual bones, indicating that the details of the boundary conditions and the cross section are key if a better understanding of the mechanical properties of bones is to be achieved. Fractures do not present a defined path, neither when they first appear, nor in their evolution along the cross section, but rather show a totally irregular section. FEM simulations point out the need of taking into account possible changes in cross section and boundary conditions of the epiphysis of femoral human bones. Finite Element computer simulations of the modal behaviour of human femur were compared to experimental results of the resonance frequencies of actual bones, indicating that the details of the boundary conditions and the cross section are key if a better understanding of the mechanical properties of bones is to be achieved. The stress distribution, in both epiphysis and diaphysis femoral regions, was determined by photoelasticity experiments. (Received November 12, 2012; Accepted January 7, 2013) Keywords: Femur; Diaphysis; Epiphysis; Modal analysis; Finite element method; Photoelasticity Background Bones, particularly long ones, are among the most fascinating and intriguing materials, not only because of the complicated structure, but also because of their mechanical behaviour 1-5 and a number of recent studies have pointed out some of their unique features, especially during fracture under severe mechanical loadin

    The 2017 Regional Election in Catalonia: An attempt to understand the pro-independence vote

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    This paper tries to unveil the main factors behind the triumph of the proindependence vote in the 2017 Regional Election in Catalonia. The empirical analysis, which is carried out at the county level and by using a spatial econometric model, reveals that geographical location matters. The estimation results also suggest that the pro-independence vote is mainly linked to the birthplace of individuals. More specifically, it shows that the independence feeling is weaker the higher the share of citizens born outside Catalonia. On the other side, young and highly educated people are more prone to independence. Additionally, it is shown that people working in the public sector are more likely to vote for a political party in favor of Catalonia remaining in Spain, while the opposite happens for those voters working in construction. Finally, the results seem to dispel some myths associated with the role played by the county’s size and level of income on the proindependence vote

    Molecular Characterization of Haemaphysalis Species and a Molecular Genetic Key for the Identification of Haemaphysalis of North America

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    Haemaphysalis longicornis (Acari: Ixodidae), the Asian longhorned tick, is native to East Asia, but has become established in Australia and New Zealand, and more recently in the United States. In North America, there are other native Haemaphysalis species that share similar morphological characteristics and can be difficult to identify if the specimen is damaged. The goal of this study was to develop a cost-effective and rapid molecular diagnostic assay to differentiate between exotic and native Haemaphysalis species to aid in ongoing surveillance of H. longicornis within the United States and help prevent misidentification. We demonstrated that restriction fragment length polymorphisms (RFLPs) targeting the 16S ribosomal RNA and the cytochrome c oxidase subunit I (COI) can be used to differentiate H. longicornis from the other Haemaphysalis species found in North America. Furthermore, we show that this RFLP assay can be applied to Haemaphysalis species endemic to other regions of the world for the rapid identification of damaged specimens. The work presented in this study can serve as the foundation for region specific PCR-RFLP keys for Haemaphysalis and other tick species and can be further applied to other morphometrically challenging taxa

    The Prevalence of Previously Undiagnosed Leprosy in the General Population of Northwest Bangladesh

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    In order to estimate the level of leprosy in an area with many leprosy patients, we determined the prevalence of previously undiagnosed leprosy in the general population and compared this with the registered (or known) number of leprosy patients. We also compared it with the known prevalence of leprosy in contacts of leprosy patients. We examined 20 randomly selected geographical clusters of 1,000 persons each in two districts of Bangladesh, with over 4 million population. Physical examination was performed on all individuals. The number of newly found leprosy cases among 17,862 people above 5 years of age from the clusters was 27, giving a rate of previously undiagnosed leprosy of 15.1 per 10,000. This rate is six times higher than the registered prevalence, but three times lower than the rate in the most distant subgroup of contacts (neighbour of neighbour and social contacts) of leprosy patients in the same area. We conclude that in areas where leprosy is common, it may be preferable to do full village or neighbourhood surveys when a new leprosy patient is found, rather than to limit contact surveys to close contacts only, such as household members
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