2,412 research outputs found
Information systems ethics â challenges and opportunities
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkThe purpose of this paper is to explore the ethical issues surrounding information systems (IS) practice with a view to encouraging greater involvement in this aspect of IS research. Information integrity relies upon the development and operation of computer-based information systems. Those who undertake the planning, development and operation of these information systems have obligations to assure information integrity and overall to contribute to the public good. This ethical dimension of information systems has attracted mixed attention in the IS academic discipline
Solar limb darkening function and solar diameter with eclipses observations
We introduce a new method to perform high resolution astrometry of the solar
diameter from the ground, through the observations of eclipses. A discussion of
the solar diameter and its variations is linked to the Limb Darkening Function
(LDF) using the luminosity evolution of a Baily's Bead and the profile of the
lunar limb available from satellite data. The inflexion point of the LDF is
defined as the solar limb. The method proposed is applied for the videos of the
eclipse in January, 15, 2010 recorded by Richard Nugent in Uganda and Andreas
Tegtmeier in India. An upper limit for the inflexion point position has been
set for that eclipse.Comment: 3 pages, 2 figures. Proceedings of the Fourth French-Chinese meeting
on Solar Physics Understanding Solar Activity: Advances and Challenges, 15 -
18 November, 2011 Nice, Franc
Frequentist Analysis of the Parameter Space of Minimal Supergravity
We make a frequentist analysis of the parameter space of minimal supergravity
(mSUGRA), in which, as well as the gaugino and scalar soft
supersymmetry-breaking parameters being universal, there is a specific relation
between the trilinear, bilinear and scalar supersymmetry-breaking parameters,
A_0 = B_0 + m_0, and the gravitino mass is fixed by m_{3/2} = m_0. We also
consider a more general model, in which the gravitino mass constraint is
relaxed (the VCMSSM). We combine in the global likelihood function the
experimental constraints from low-energy electroweak precision data, the
anomalous magnetic moment of the muon, the lightest Higgs boson mass M_h, B
physics and the astrophysical cold dark matter density, assuming that the
lightest supersymmetric particle (LSP) is a neutralino. In the VCMSSM, we find
a preference for values of m_{1/2} and m_0 similar to those found previously in
frequentist analyses of the constrained MSSM (CMSSM) and a model with common
non-universal Higgs masses (NUHM1). On the other hand, in mSUGRA we find two
preferred regions: one with larger values of both m_{1/2} and m_0 than in the
VCMSSM, and one with large m_0 but small m_{1/2}. We compare the probabilities
of the frequentist fits in mSUGRA, the VCMSSM, the CMSSM and the NUHM1: the
probability that mSUGRA is consistent with the present data is significantly
less than in the other models. We also discuss the mSUGRA and VCMSSM
predictions for sparticle masses and other observables, identifying potential
signatures at the LHC and elsewhere.Comment: 18 pages 27 figure
Tracking SCUBA Diving adventure tourism in South Africa
Abstract. The aim of this study is to investigate some of the trends associated with SCUBA diving within an adventure tourism framework. Previous research has shown the increase in adventure tourism, globally, as well as its economic contribution to national economies, particularly those in developing countries such as South Africa. As one of the oldest forms of adventure tourism, SCUBA diving, in particular, has the potential to generate significant income due to the training requirements, the specialized equipment required and the trend of career participation in the activity. This study analyzed the SCUBA industry in South Africa through 106 questionnaires distributed to SCUBA divers. The results show that there is a trend of repeat participation in SCUBA dive tourism and the economic implications are significant. Furthermore, it demonstrates evidence of the development of SCUBA communities in the country, encouraging continued participation. The results have important implications for the potential contribution of SCUBA diving to the South African adventure tourism industry. It also highlighted some of the aspects that could either attract or deter more people from engaging in SCUBA diving in South Africa, which has product development and marketing implications. This work brings initial insight into an important tourism subsector which generates significant income and has a strong potential for further development in South Africa
âYou know that's a rip-offâ: policies and practices surrounding micro-enterprises and poverty alleviation in South African township tourism
Supporting the development of small tourism businesses has been seen by policy-makers as a valuable means of alleviating poverty in South African townships. This perspective has been endorsed by several âresponsibleâ tourism businesses and academics. Following a review of the literature, this paper reports the findings of an empirical study that examined the practices of micro-business owners and the factors that shape their behaviour in two South African townships. In spite of significant visitor numbers, it finds that their narrow social networks and the imbalances of power between them and intermediaries such as travel agencies and tour operators prevent them from developing their businesses and sharing in the material gains that become available because of tourism. This analysis has important implications for local policy-makers and those advocating responsible tourism. For the former, it suggests a cessation of current initiatives in favour of greater regulation and alternative forms of investment. For the latter, it implies the need to reassess the utility of advocating responsible tourism to consumers in a context where they do not understand the dynamics which fashion what is on offer or the full implications of their choices
Winter Feeding of Elk in the Greater Yellowstone Ecosystem and its Effects on Disease Dynamics
Providing food to wildlife during periods when natural food is limited results in aggregations that may facilitate disease transmission. This is exemplified in western Wyoming where institutional feeding over the past century has aimed to mitigate wildlifeâlivestock conflict and minimize winter mortality of elk (Cervus canadensis). Here we review research across 23 winter feedgrounds where the most studied disease is brucellosis, caused by the bacterium Brucella abortus. Traditional veterinary practices (vaccination, test-and-slaughter) have thus far been unable to control this disease in elk, which can spill over to cattle. Current disease-reduction efforts are being guided by ecological research on elk movement and density, reproduction, stress, co-infections and scavengers. Given the right tools, feedgrounds could provide opportunities for adaptive management of brucellosis through regular animal testing and population-level manipulations. Our analyses of several such manipulations highlight the value of a researchâmanagement partnership guided by hypothesis testing, despite the constraints of the sociopolitical environment. However, brucellosis is now spreading in unfed elk herds, while other diseases (e.g. chronic wasting disease) are of increasing concern at feedgrounds. Therefore experimental closures of feedgrounds, reduced feeding and lower elk populations merit consideration
Disruption of Var2csa Gene Impairs Placental Malaria Associated Adhesion Phenotype
Infection with Plasmodium falciparum during pregnancy is one of the major causes of malaria related morbidity and mortality in newborn and mothers. The complications of pregnancy-associated malaria result mainly from massive adhesion of Plasmodium falciparum-infected erythrocytes (IE) to chondroitin sulfate A (CSA) present in the placental intervillous blood spaces. Var2CSA, a member of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family is the predominant parasite ligand mediating CSA binding. However, experimental evidence suggests that other host receptors, such as hyaluronic acid (HA) and the neonatal Fc receptor, may also support placental binding. Here we used parasites in which var2csa was genetically disrupted to evaluate the contribution of these receptors to placental sequestration and to identify additional adhesion receptors that may be involved in pregnancy-associated malaria. By comparison to the wild-type parasites, the FCR3Îvar2csa mutants could not be selected for HA adhesion, indicating that var2csa is not only essential for IE cytoadhesion to the placental receptor CSA, but also to HA. However, further studies using different pure sources of HA revealed that the previously observed binding results from CSA contamination in the bovine vitreous humor HA preparation. To identify CSA-independent placental interactions, FCR3Îvar2csa mutant parasites were selected for adhesion to the human placental trophoblastic BeWo cell line. BeWo selected parasites revealed a multi-phenotypic adhesion population expressing multiple var genes. However, these parasites did not cytoadhere specifically to the syncytiotrophoblast lining of placental cryosections and were not recognized by sera from malaria-exposed women in a parity dependent manner, indicating that the surface molecules present on the surface of the BeWo selected population are not specifically expressed during the course of pregnancy-associated malaria. Taken together, these results demonstrate that the placental malaria associated phenotype can not be restored in FCR3Îvar2csa mutant parasites and highlight the key role of var2CSA in pregnancy malaria pathogenesis and for vaccine development
Three cases of bacteremia caused by Vibrio cholerae O1 in Blantyre, Malawi.
We report three fatal cases of bacteremia (two adults, one neonate) caused by Vibrio cholerae O1 (Ogawa), which occurred in the context of a community outbreak of cholera diarrhea in Blantyre, Malawi. Only four cases of invasive disease caused by V. cholerae O1 have previously been reported. We describe the clinical features associated with these rare cases and discuss their significance
Effect of spironolactone and potassium canrenoate on cytosolic and nuclear androgen and estrogen receptors of rat liver
Spironolactone and potassium canrenoate are diuretics that are used widely for management of cirrhotic ascites. The administration of spironolactone frequently leads to feminization, which has been noted less frequently with the use of potassium canrenoate, a salt of the active metabolite of spironolactone. The use of these two drugs has been associated with decreases in serum testosterone levels and spironolactone with a reduction in androgen receptor (AR) activity. This decrease in AR has been cited as the cause of the antiandrogen effect of these drugs. We therefore assessed the effect of both drugs on levels of androgen and estrogen receptors (ER) in the liver, a tissue that is responsive to sex steroids. Three groups of male rats (n = 12 rats each) were studied. Group 1 (control) received vehicle only; group 2 received spironolactone (5 mg/day); group 3 received potassium canrenoate (5 mg/day). After 21 days of treatment, the animals of all groups were killed and liver tissue was assayed for nuclear and cytosolic AR and ER, and for male specific estrogen binder (MEB), an androgen-responsive protein. Both drugs drastically decreased the nuclear AR content, as compared with the control group, but only spironolactone decreased cytosolic AR. When the total hepatic content of AR is considered, a highly significant decrease is observed only in rats treated with spironolactone. This reduction in hepatic AR content suggested loss of androgen responsiveness of liver. We confirmed this by assessing levels of MEB, and found that livers from group 2 animals had no detectable MEB activity, whereas livers from both group 1 and 3 had normal MEB activity. No changes were observed in nuclear ER and cytosolic ER of group 3 as compared with group 1. Nuclear estrogen receptor decreased and cytosolic ER increased in group 2, but with no change in total ER content. These results indicate that (a) only spironolactone appears to act as an antiandrogen in liver, resulting in a decrease in both AR and male specific estrogen binder content, and (b) neither drug results in elevated hepatic ER content, although spironolactone-treated animals show an altered subcellular localization. © 1987
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