Composition of waters of lakes and rivers in east and west Africa

Thirty-three groups of geochemically related natural lake and river waters collected from 368 sites scattered over East and West Africa, were investigated to determine correlations between their various ions and the patterns of change in their ionic composition across the African continent. The following nine significant correlations were found to exist in the entire area or in a major part of it: sodium and potassium; sodium and chloride; sodium and sulphate; potassium and ammonium; potassium and chloride; ammonium and nitrate; calcium and magnesium; magnesium and chloride; sulphate and chloride. When compared with the world average composition. The concentration of potassium in these waters was found to be high, that of calcium and nitrate was low. With respect to the area of East Africa only, trends in the pattern of change involving the ionic composition of the lake and river water and the longitude at which the sites were present, were found to exist for the ratio of sodium: conductivity (which showed an increase in the direction of West to East), magnesium: conductivity, and for the sum of calcium and magnesium: phosphate was generally found to increase in East Africa in the direction of west to East

Differences between physicians in the likelihood of referral and acceptance of elderly patients for dialysis-influence of age and comorbidity

BACKGROUND: Incidence of dialysis in elderly patients in the Netherlands is low compared to other countries. This study aims to assess the impact of patients' age and comorbidity on the likelihood of referral and acceptance of patients for dialysis and whether this is affected by physician characteristics. METHODS: A vignette study was performed among 209 primary care physicians, 162 non-nephrology specialists and 20 nephrologists working in the north of the Netherlands. Physicians were offered six vignettes concerning case-reports of patients with end-stage renal disease (ESRD) and varying comorbidities or circumstances and asked about the likelihood of referral/acceptance of the patient in the given circumstances. RESULTS: The likelihood of referral within groups of physicians varied widely, especially within the group of primary care physicians and non-nephrology specialists, but was not affected by characteristics of physicians. The likelihood of referral or acceptance of patients for dialysis depended on the patient's age, and type and severity of comorbidity. In general, primary care physicians and non-nephrology specialists were less likely to refer than nephrologists were to accept. Differences within and between groups of physicians were larger for 80- than for 65-year-old patients, and for patients with less severe shortness of breath and cognitive impairments and more severe diabetes and social impairments. Hardly any differences were found for patients with cancer. CONCLUSION: Patients' age and comorbidities affect the likelihood of referral. Differences between groups of physicians suggest that there is insufficient agreement on the extent to which these factors should affect the referral/acceptance of patients for dialysis. These findings underline the need for more research into circumstances under which patients might benefit from dialysis. Guidelines should be developed to improve the referral of elderly and less healthy patients

A review of the distribution of organic compounds in freshwater lakes and rivers

The paper reviews the distribution of organic compounds in freshwater lakes and rivers. The study of dissolved organic matter in natural lakes and rivers is of importance for a variety of reasons. The organic matter may serve in part or whole as an energy source for organisms living in the aquatic environment, or it may supply them with materials essential for their nutrition

Accepting or declining dialysis: considerations taken into account by elderly patients with end-stage renal disease

BACKGROUND: Elderly patients with end-stage renal disease have to make a difficult decision whether or not to start dialysis. This study explores the considerations taken into account by these patients in decision-making regarding renal replacement therapy. METHOD: In-depth interviews were conducted to gain an enhanced understanding of the considerations in treatment decision-making. Fourteen patients aged 65 years or older participated in the interviews, of whom 8 patients had made the decision to start, and 6 patients the decision to decline, dialysis. RESULTS: All participating patients had a variety of health problems, but appeared to have normal cognitive functions. Patients who declined dialysis were older and more often men and widow(er)s compared with patients who accepted dialysis. Patients chose to start dialysis because they enjoyed life, were not prepared to face the end of life, felt they had no other choice or had care-giving responsibilities for family members. Patients declined dialysis because of the speculated loss of autonomy, their age-associated decrease in vitality, distance from dialysis center and reluctance to think about the future. CONCLUSION: Results suggest that patients' decisions to decline or accept dialysis are not based on the effectiveness of the treatment, but rather on personal values, beliefs and feelings toward life, suffering and death, and the expected difficulties in fitting the treatment into their life

Factors impacting upon Australian university student participation in educational exchange programs

With globalisation and technological innovation changing the global marketplace, research (e.g. Australian International Education Foundation, 1998; Kling, Alexander, McCorkle, & Martinez, 1999; Webb, Mayer, Pioche, & Allen, 1999) has shown that employers are seeking graduates with international competencies. Moreover, it is argued that it is the role of universities to prepare students to work in the new international context, thus meeting the needs of business and society (Fantini, Arias-Galicia, & Guay, 2001; Higher Education Council, 1990). International education opportunities such as student exchange programs have been identified as effective means through which university students may develop such skills and knowledge (Clyne & Rizvi, 1998; Fantini et al., 2001; Wallace, 1993). Currently, less than one percent of Australian undergraduate students complete part of their qualification in an overseas institution (IDP Education Australia, 1995). Much research to date has focused on issues such as psychological and social adjustment of international students. Yet, there is a paucity of literature relating to the effects of international education experiences for Australian domestic students. Hence, this paper will examine the issues affecting Australian students’ participation in academic mobility programs, with a particular focus on the factors influencing the decision to participate in a student exchange program

Assessment of Interspecies Differences in Drug-Induced QTc Interval Prolongation in Cynomolgus Monkeys, Dogs and Humans.

BACKGROUND AND PURPOSE The selection of the most suitable animal species and subsequent translation of the concentration-effect relationship to humans are critical steps for accurate assessment of the pro-arrhythmic risk of candidate molecules. The objective of this investigation was to assess quantitatively the differences in the QTc prolonging effects of moxifloxacin between cynomolgus monkeys, dogs and humans. The impact of interspecies differences is also illustrated for a new candidate molecule. EXPERIMENTAL APPROACH Pharmacokinetic data and ECG recordings from pre-clinical protocols in monkeys and dogs and from a phase I trial in healthy subjects were identified for the purpose of this analysis. A previously established Bayesian model describing the combined effect of heart rate, circadian variation and drug effect on the QT interval was used to describe the pharmacokinetic-pharmacodynamic relationships. The probability of a ≥ 10 ms increase in QT was derived as measure of the pro-arrhythmic effect. KEY RESULTS For moxifloxacin, the concentrations associated with a 50% probability of QT prolongation ≥ 10 ms (Cp50) varied from 20.3 to 6.4 and 2.6 μM in dogs, monkeys and humans, respectively. For NCE05, these values were 0.4 μM vs 2.0 μM for monkeys and humans, respectively. CONCLUSIONS AND IMPLICATIONS Our findings reveal significant interspecies differences in the QT-prolonging effect of moxifloxacin. In addition to the dissimilarity in pharmacokinetics across species, it is likely that differences in pharmacodynamics also play an important role. It appears that, regardless of the animal model used, a translation function is needed to predict concentration-effect relationships in humans

Static semifluxons in a long Josephson junction with π-discontinuity points

We investigate analytically a long Josephson junction with several $\pi$-discontinuity points characterized by a jump of $\pi$ in the phase difference of the junction. The system is described by a perturbed-combined sine-Gordon equation. Via phase-portrait analysis, it is shown how the existence of static semifluxons localized around the discontinuity points is influenced by the applied bias current. In junctions with more than one corner, there is a minimum-facet-length for semifluxons to be spontaneously generated. A stability analysis is used to obtain the minimum-facet-length for multicorner junctions

Which clinical signs are valid indicators for speech language disorder?

Presentatie in werkgroep richtlijnontwikkeling taalontwikkelin

Traversable Wormholes Construction in 2+1 Dimensions

We study traversable Lorentzian wormholes in the three-dimensional low energy string theory by adding some matter source involving a dilaton field. It will be shown that there are two-different types of wormhole solutions such as BTZ and black string wormholes depending on the dilaton backgrounds, respectively. We finally obtain the desirable solutions which confine exotic matter near the throat of wormhole by adjusting NS charge.Comment: 12 pages, 4 figures, JHEP style, one reference adde