A Cosmic Ray Positron Anisotropy due to Two Middle-Aged, Nearby Pulsars?

Geminga and B0656+14 are the closest pulsars with characteristic ages in the ran ge of 100 kyr to 1 Myr. They both have spindown powers of the order 3e34 erg/s at present. The winds of these pulsars had most probably powered pulsar wind nebulae (PWNe) that broke up less than about 100 kyr after the birth of the pulsars. Assuming that leptonic particles accelerated by the pulsars were confined in th e PWNe and were released into the interstellar medium (ISM) on breakup of the PW Ne, we show that, depending on the pulsar parameters, both pulsars make a non-ne gligible contribution to the local cosmic ray (CR) positron spectrum, and they m ay be the main contributors above several GeV. The relatively small angular dist ance between Geminga and B0656+14 thus implies an anisotropy in the local CR po sitron flux at these energies. We calculate the contribution of these pulsars to the locally observed CR electr on and positron spectra depending on the pulsar birth period and the magnitude o f the local CR diffusion coefficient. We further give an estimate of the expecte d anisotropy in the local CR positron flux. Our calculations show that within the framework of our model, the local CR posit ron spectrum imposes constraints on pulsar parameters for Geminga and B0656+14, notably the pulsar period at birth, and also the local interstellar diffusion co efficient for CR leptons.Comment: accepted for publication in ApJ

A novel application of phosphogypsum: Treatment of a diamond mine\'s slimes tailings

Premier Mine\'s current slimes dam is nearing the end of its operational life. This is aggravated by a large volume of poor quality water in the dam which is not being recycled back into the process. The poor quality water is the result of a stable colloidal suspension formed from the dominant clay species present in the kimberlitic ore body. The main objective of this test work was to clarify the water to improve the quality for reuse. Phosphogypsum has been identified as an alternative coagulant to clarify the slimes dam water at a relatively low cost. Laboratory- and plant-scale test work was done to investigate the optimum gypsum dosage, as well as to determine the most suitable application technique. The test work showed that gypsum can successfully destabilise the colloidal suspension. However, poor settling rates were achieved. This improved when the gypsum was added in a slurry form in two stages. The addition of flocculants to aid in settling did not have the desired effect, with resultant high consumption and operating costs. Toxicity tests indicated no lethality to Daphnia organisms and showed a positive growth in the algae test. The establishment of a monitoring programme will assist in determining the long-term effects of gypsum on the environment. Water SA Vol.32 (4) 2006: pp.489-49

Blistering rash in a young male child

A 3-year-old child was brought to the casualty department at Leratong Hospital, Johannesburg, South Africa, with severe bullous eruptions on the distal portions of both the upper and lower limbs. He had visited three different general practitioners prior to presentation and had been given several drugs and ointments, including three different classes of antibiotics. During his admission, the diagnosis of linear IgA bullous dermatitis was made. Dapsone and prednisone were given and he recovered well

Designing for user experience : analysing app store reviews for app feature identification

Abstract: South Africa's blood stock level is often categorised as alarmingly low, leaving blood donation organisations in constant need of voluntary, unpaid blood donations to ensure their ability to supply hospitals with safe blood. Globally, there are successful mobile blood donation apps facilitating blood donation by providing useful services to blood donors, however similar apps available in South Africa are new, and not popular when compared to global standards. An estimated 5.9 million South Africans download and use mobile applications (apps), and this paper explores the process and results from the first phase of a study, which employed a sequential mixed method research design, to identify userpreferred features for a mobile blood donation app. The findings of the study should serve as a roadmap to blood donation organisations in South Africa, regarding what users expect from a blood donation app, and which features may possibly stimulate a constant or increased frequency of blood donation instances. The two largest app stores, Google Play and Apple iOS, served as the sources of the eventual sample of blood donation apps, of which the user reviews were analysed. Commenting from a design science paradigm, this paper reports on the selection process that had been followed to sample the relevant apps, and further discusses the user insights gained from the analysis of these apps' reviews. The paper further reports on how the app review analysis findings informed the creation of an interview schedule, that was used to gain in-depth understanding of perceptions held by users of the blood donation apps, specifically regarding the users' preferred features in these types of apps

Gene editing of three BnITPK genes in tetraploid oilseed rape leads to significant reduction of phytic acid in seeds

Commercialization ofBrassica napus.L (oilseed rape) meal as protein diet is gaining moreattention due to its well-balanced amino acid and protein contents. Phytic acid (PA) is a majorsource of phosphorus in plants but is considered as anti-nutritive for monogastric animalsincluding humans due to its adverse effects on essential mineral absorption. The undigested PAcauses eutrophication, which potentially threatens aquatic life. PA accounts to 2-5% in matureseeds of oilseed rape and is synthesized by complex pathways involving multiple enzymes.Breeding polyploids for recessive traits is challenging as gene functions are encoded by severalparalogs. Gene redundancy often requires to knock out several gene copies to study theirunderlying effects. Therefore, we adopted CRISPR-Cas9 mutagenesis to knock out threefunctional paralogs ofBnITPK. We obtained low PA mutants with an increase of free phosphorusin the canola grade spring cultivar Haydn. These mutants could mark an important milestone inrapeseed breeding with an increase in protein value and no adverse effects on oil contents

Selfgetuienis en interpretasie

Self-evidence and interpretation Hermeneutics has become a major issue in current theological thought. It is quite apparent that the interpretation of Holy Scripture is one of the most often discussed subjects amongst theologians. As to the authority of the Bible, its self-evidence is a particularly noticeable factor. This in turn has a direct bearing on the explicatio and applicatio o f Scripture in preaching, and consequently on the very life of the church. It is argued that, even though the human factor should not be minimized, God Himself is subject of his Word in those various statures in which it addresses mankind

Perspectives on the doctrine of providence in some of Calvin' s sermons on Job

It is quite remarkable that Calvin addresses himself to the providence of God not only in his 'theological' works (eg Institutes), but particularly also in his more 'popular' works, for instance his correspondence and sermons. This is where the doctrine of providence is significantly contextualized. It is obvious that he takes up his topic in a most responsible manner, by which the 'providentia Dei' should not only comfort those who believe in Christ, but should also call for a responsible life before the countenance of God. Furthermore, for Calvin providence is not so much an issue to be 'explained', but rather a 'confession' related to the very heart of faith.Spine cut of Journal binding and pages scanned on flatbed EPSON Expression 10000 XL; 400dpi; text/lineart - black and white - stored to Tiff Derivation: Abbyy Fine Reader v.9 work with PNG-format (black and white); Photoshop CS3; Adobe Acrobat v.9 Web display format PDFhttp://explore.up.ac.za/record=b1001341wm201

The physical and emotional results of hysterectomy

Our interest in the physical and emotional results of hysterectomy was stimulated by recent letters in the British Medical Journal concerning the psychological preparation of patients for hysterectomy and especially by Or. K. Dalton's dismal picture of the aftermath of the operation. In our practices we deal mainly with a rural community in the Eastern Cape consisting of wool, apple and citrus farmers and their families. This report is a follow-up of patients treated by hysterectomy during the last 5 years

Perspectives on the doctrine of providence in some of Calvin' s sermons on Job

It is quite remarkable that Calvin addresses himself to the providence of God not only in his 'theological' works (eg Institutes), but particularly also in his more 'popular' works, for instance his correspondence and sermons. This is where the doctrine of providence is significantly contextualized. It is obvious that he takes up his topic in a most responsible manner, by which the 'providentia Dei' should not only comfort those who believe in Christ, but should also call for a responsible life before the countenance of God. Furthermore, for Calvin providence is not so much an issue to be 'explained', but rather a 'confession' related to the very heart of faith.Spine cut of Journal binding and pages scanned on flatbed EPSON Expression 10000 XL; 400dpi; text/lineart - black and white - stored to Tiff Derivation: Abbyy Fine Reader v.9 work with PNG-format (black and white); Photoshop CS3; Adobe Acrobat v.9 Web display format PDFhttp://explore.up.ac.za/record=b1001341wm201

A rapid and low-cost DNA extraction method for isolating Escherichia coli DNA from animal stools

The price of commercial DNA extraction methods makes the routine use of polymerase chain reaction amplification (PCR) based methods rather costly for scientists in developing countries. A guanidium thiocayante-based DNA extraction method was investigated in this study for the isolation of Escherichia coli (E. coli) DNA from goat, chicken, pig, cow and human stool samples. Two versions of the lysis buffer, with and without _-casein, were tested to alleviate PCR inhibition associated with DNA isolated from stool samples. Results obtained show that, this method using the lysis buffer containing _-casein, produces PCR ready DNA at a fraction of the cost of commercial DNA extraction kits & copy; 2011 Academic Journals