Use of in-stream reservoirs to reduce bacterial contamination of rural watersheds

An investigation into bacterial water quality problems was conducted on an interconnected stream and irrigation system within the Oldman River Basin of southern Alberta, Canada. Levels of indicator bacteria, including fecal coliforms, generic Escherichia coli and fecal streptococci, were repeatedly measured in streams and irrigation return canals of this river basin during the summer of 2001. Bacterial-loading segments of the irrigation/stream system were identified through a comparison of indicator bacteria levels in pairs of upstream and downstream sites. Mann-Whitney U-tests indicated that reservoirs significantly reduced bacterial counts. A temporal comparison of E. coli counts and river discharges suggested that these indicator bacteria do not originate from within in-stream sediments. Site-specific as well as cumulative inputs from a variety of non-point sources are likely to be responsible for the high downstream levels of indicator bacteria in this water system. The use of management practices such as in-stream reservoirs may significantly reduce contamination, and increase the quality of limited rural water supplies to allow their reuse and safe discharge into downstream water sources. The identification of bacteria-loading river/canal segments could also be used to prioritize restoration projects.     

Molecular subtypes of Campylobacter spp., Salmonella enterica, and Escherichia coli O157:H7 isolated from faecal and surface water samples in the Oldman River watershed, Alberta, Canada

Campylobacter spp., Salmonella enterica, and Escherichia coli O157:H7 isolated from 898 faecal, 43 sewage, and 342 surface water samples from the Oldman River were characterized using bacterial subtyping methods in order to investigate potential sources of contamination of the watershed. Among these pathogens, Campylobacter spp. were the most frequently isolated from faecal, sewage, and surface water samples (266/895, 11/43, and 91/342, respectively), followed by Salmonella (67/898, 8/43, and 29/342, respectively), and E. coli O157:H7 (16/898, 2/43, and 8/342, respectively). Salmonella Rubislaw was the most common serovar isolated from water. This serovar was also isolated from two wild bird species. Most other serovars isolated from water were either not isolated from animals or were isolated from multiple species. E. coli O157:H7 was predominantly isolated from cattle. The most common phage-types of this pathogen from cattle were also the most common among water isolates, and there were exact pulsed field gel electrophoresis and comparative genomic fingerprint matches between cattle, sewage, and water isolates. Campylobacters were commonly isolated from surface waters and faeces from most animal species. Restriction fragment length polymorphism of the Campylobacter flaA gene identified several location and host species-specific (cattle, goose, pig) fingerprints. Molecular subtyping of these bacterial pathogens shows considerable promise as a tool for determining the sources of faecal pollution of water.     

Primary beneficiation of tantalite using magnetic separation and acid leaching

Primary beneficiation was successfully performed prior to dissolution of manganotantalite （sample A） and ferrotantalite （sample C） samples obtained from two different mines in the Naquissupa area, Mozambique. Magnetic separation removed the majority of iron and titanium, whereas H2SO4 leaching removed a large portion of thorium and uranium in these samples. Analytical results indicated that 64.14wt% and 72.04wt% of the total Fe and Ti, respectively, and -2wt% each of Nb205 and Ta205 were removed from sample C （ferrotantalite） using the magnetic separation method, whereas only 9.64wt% and 8.66wt% of total Fe203 and TiO2, respectively, and -2wt% each of NbEOs and Ta2O5 were removed from sample A （manganotantalite）. A temperature of 50℃ and a leaching time of 3 h in the presence of concentrated HESOa were observed to be the most appropriate leaching conditions for removal of radioactive elements from the tantalite ores. The results obtained for sample A under these conditions indicated that 64.14wt% U3O8 and 60.77wt% ThO2 were leached into the acidic solution, along with 4.45wt% and 0.99wt% of Nb2O5 and Ta2O5, respectively.     

Investigating the Information Systems Heterarchy

This article assesses how one IS organization is changing in response to the increased globalization of software development and posits the emergence of a new form of multi-national enterprise (MNE)—the heterarchy. Data from two projects create new insights into the structures and behaviors of IS MNEs as they adapt to global systems development. The article identifies four primary dimensions of impact—cultural, economic, operational, and organizational—and suggests how such organizations are evolving.     

Liquid-liquid extraction and separation of total rare earth (RE) metals from polymetallic manganese nodule leaching solution

The study on the solvent extraction for quantitative and selective separation of total rare earth metals from the polymetallic nodule leach liquor was investigated. The typical leach liquor bearing 0. 094 g/L total rare earth, 0. 23 g/L Mn, 0.697 g/L Cu, 0.2 g/L Fe, 0.01 g/L Co and 0.735 g/L Ni was subjected to the removal iron content by precipitation method using Ca(OH)2 at pH 3.95, prior to solvent extraction of rare earth metals. Three different organo-phosphoric acid reagents(D2EHPA, PC88 A, Cyanex 272) were used to ascertain their performances and selectivity towards the loading of rare earth metals in presence of other base metals. Based on the results of eq. pH effect, the performances of above three extractants followed the order as: D2EHPA>PC88A>Cyanex 272. To ensure the absence of extraction of base metals(Cu, Co, Ni), the eq. pH of the solution was optimized at the level of 2.21, though higher rare earth metal extraction efficiency was observed at higher eq. pH with either of the extractants. The complete process flow diagram for substantial recovery of total rare earth was developed using D2 EHPA. Extraction isotherm plot was constructed at A:O=12:1, 3-stages and pHe=2.21, using 0.8 mol/L D2 EHPA and the predicted condition of this study was further confirmed by 6-Cycles Counter Current Simulation(CCS) study. The stripping of total rare earth from loaded organic phase(LO) was conducted using HCl solution. Mc-Cabe Thiele diagram study carried out at A:O=1:5 using 4 mol/L HCl showed that three theoretical stages were needed for quantitative stripping of total rare earth. The subsequent stripped solution resulted thus led to contain total rare earth of 5.6 g/L indicating a very high enrichment of total metals by solvent extraction(SX) process.     

Effect of short-term hormone replacement therapy on left ventricular mass and contractile function

This study examined the effects of neonatal cocaine exposure on the rewarding properties of play in a modified T-maze. Animals were artificially reared from postnatal day (PND) 4-9 with drug concentrated in four daily feeds. There were four treatment groups, 40 mg/kg/day cocaine, 20 mg/kg/day cocaine, an artificially reared control and a surgery control. From PND 38-42, subjects were tested with a food reward (EXP 1) or a play reward (EXP 2). No deficits in learning were seen when the reward was food. The 20 mg/kg/day cocaine group, however, showed impaired learning and altered play behavior when the reward was access to a play partner. Neonatal cocaine exposure thus appears to differentially affect learning based on the type of reward presented.     

Orthopedic management of osteopetrosis: results of a survey and review of the literature

Osteopetrosis or Albers-Schonberg disease is a rare hereditary disorder of osteoclast function in which resorption of bone is diminished, resulting in abnormally dense bones. The condition is known to occur in at least four recognizable clinical patterns, each of which is variable. The optimal treatment of fractures and of bone deformity in these patients has not previously been made clear. To determine appropriate orthopedic management of the condition, we conducted a survey of the membership of the Pediatric Orthopedic Society of North America. The combined experience of 57 surgeons who treated 79 patients with osteopetrosis was compiled. Four femoral neck fractures treated by closed reduction and internal fixation had a satisfactory result, but three treated nonoperatively developed varus and required osteotomy. A total of 20 hips was treated for coxa vara by various means, none of which was free of complications. Valgus osteotomy, when used as the primary treatment for coxa vara, was the most consistently satisfactory procedure, whereas in situ pinning failed in two of three hips. Fourteen subtrochanteric fractures and 31 other fractures of the femur were treated. Good results were reported with traction or casting or both in the majority of those fractures. Twenty-nine tibia fractures were treated successfully, the majority by nonoperative means. Upper extremity fractures healed well with closed reduction and casting. Vertebral fractures, spondylolysis, and back pain were most frequently treated without surgery.     

Retrospective analysis of the Beijing family of Mycobacterium tuberculosis in preserved lung tissues

Direct repeat spoligotyping of 85 paraffin-embedded lung biopsies was used to investigated the occurrence around Beijing of the Beijing family of Mycobacterium tuberculosis. Samples ranged in time from 1956 to 1990. Hybridization patterns were found with 49 (58%) samples, and 45 (92%) produced typical Beijing family patterns extending over the 34-year period.     

Enhanced oxygen delivery reverses anaerobic metabolic states in prolonged sandwich rat hepatocyte culture

It must be assumed that current petri dish primary hepatocyte culture models do not supply sufficient amounts of oxygen and thus cause anaerobic metabolism of the cells. This is contrary to the physiologic state of the cells. In vivo the liver is a highly vascularized organ with a rather high blood flow rate of a mixture of arterial and venous blood. The aim of the present study was to show the oxygen dependence of primary rat hepatocytes in long-term culture and to define appropriate conditions that could allow hepatocytes to maintain tissue specific functions in an aerobic environment. To this purpose matrix overlaid hepatocytes were either cultured on gas-permeable (fluorinated hydrocarbon films) or gas-impermeable (polystyrene) supports at 10% and 20% ambient oxygen concentration (v/v), respectively. Tissue-specific functions were assessed by studying albumin and urea secretion as well as xenobiotic metabolism. The mRNA expression and catalytic activities of the cytoprotective antioxidant enzymes mitochondrial manganese superoxide dismutase (MnSOD), cytosolic copper and zinc superoxide dismutase, peroxisomal catalase, and cytosolic glutathione peroxidase were investigated to assess intracellular responses to the defined variations in oxygen supply. Hepatocytes could successfully be maintained at aerobic conditions in long-term culture on gas-permeable PTFE films. At 50% (10%, v/v) of currently used oxygen levels lactate accumulation was prevented, a plateau-like albumin secretion reestablished, urea secretion improved, and xenobiotic metabolism proceeded at physiological rates. mRNA expression of cytoprotective enzymes responded to the pericellular availability of oxygen and was most pronounced in the case of MnSOD. However, the biggest stress factor for the hepatocytes still appeared to be the isolation procedure, as mRNA expression and catalytic activities were most elevated shortly thereafter. In conclusion, this study clearly shows the oxygen dependence of primary rat hepatocytes in long-term culture and indicates means to establish appropriate conditions for the aerobic culture of primary rat sandwich hepatocytes with full maintenance of function. The long-term culture of hepatocytes on oxygenating supports at in vivo-like oxygen tensions therefore appears to be more physiologic and beneficial for the cells.     

Developing a culture of lifelong learning in a library environment

Between 1995 and 1996, the Annette and Irwin Eskind Biomedical Library (EBL) at Vanderbilt University Medical Center (VUMC) radically revised the model of service it provides to the VUMC community. An in-depth training program was developed for librarians, who began to migrate to clinical settings and establish clinical librarianship and information brokerage services beyond the library's walls. To ensure that excellent service would continue within the library, EBL's training program was adapted for library assistants, providing them with access to information about a wide variety of work roles and processes over a four to eight-month training period. Concurrently, customer service areas were reorganized so that any question--whether reference or circulation--could be answered at any of four service points, eliminating the practice of passing customers from person to person between the reference and circulation desks. To provide an incentive for highly trained library assistants to remain at EBL, management and library assistants worked together to redesign the career pathway based on defined stages of achievement, self-directed participation in library-wide projects, and demonstrated commitment to lifelong learning. Education and training were the fundamental principles at the center of all this activity.