Low-energy interaction of composite spin-half systems with scalar and vector fields

We consider a composite spin-half particle moving in spatially-varying scalar and vector fields. The vector field is assumed to couple to a conserved charge, but no assumption is made about either the structure of the composite or its coupling to the scalar field. A general form for the piece of the spin-orbit interaction of the composite with the scalar and vector fields which is first-order in momentum transfer ${\bf Q}$ and second-order in the fields is derived.Comment: 10 pages, RevTe

Managerial competencies of hospital managers in South Africa: a survey of managers in the public and private sectors

<p>Abstract</p> <p>Background</p> <p>South Africa has large public and private sectors and there is a common perception that public sector hospitals are inefficient and ineffective while the privately owned and managed hospitals provide superior care and are more sustainable. The underlying assumption is that there is a potential gap in management capacity between the two sectors. This study aims to ascertain the skills and competency levels of hospital managers in South Africa and to determine whether there are any significant differences in competency levels between managers in the different sectors.</p> <p>Methods</p> <p>A survey using a self administered questionnaire was conducted among hospital managers in South Africa. Respondents were asked to rate their proficiency with seven key functions that they perform. These included delivery of health care, planning, organizing, leading, controlling, legal and ethical, and self-management. Ratings were based on a five point Likert scale ranging from very low skill level to very high skill level.</p> <p>Results</p> <p>The results show that managers in the private sector perceived themselves to be significantly more competent than their public sector colleagues in most of the management facets. Public sector managers were also more likely than their private sector colleagues to report that they required further development and training.</p> <p>Conclusion</p> <p>The findings confirm our supposition that there is a lack of management capacity within the public sector in South Africa and that there is a significant gap between private and public sectors. It provides evidence that there is a great need for further development of managers, especially those in the public sector. The onus is therefore on administrators and those responsible for management education and training to identify managers in need of development and to make available training that is contextually relevant in terms of design and delivery.</p

Nitrogen turnover and N2_{2}O/N2_{2} ratio of three contrasting tropical soils amended with biochar

Biochar has been reported to reduce emission of nitrous oxide (N$_{2}$O) from soils, but the mechanisms responsible remain fragmentary. For example, it is unclear how biochar effects on N$_{2}$O emissions are mediated through biochar effects on soil gross N turnover rates. Hence, we conducted an incubation study with three contrasting agricultural soils from Kenya (an Acrisol cultivated for 10-years (Acrisol10); an Acrisol cultivated for over 100-years (Acrisol100); a Ferralsol cultivated for over 100 years (Ferralsol)). The soils were amended with biochar at either 2% or 4% w/w. The $^{15}$N pool dilution technique was used to quantify gross N mineralization and nitrification and microbial consumption of extractable N over a 20-day incubation period at 25 °C and 70% water holding capacity of the soil, accompanied by N$_{2}$O emissions measurements. Direct measurements of N$_{2}$ emissions were conducted using the helium gas flow soil core method. N$_{2}$O emissions varied across soils with higher emissions in Acrisols than in Ferralsols. Addition of 2% biochar reduced N$_{2}$O emissions in all soils by 53 to 78% with no significant further reduction induced by addition at 4%. Biochar effects on soil nitrate concentrations were highly variable across soils, ranging from a reduction, no effect and an increase. Biochar addition stimulated gross N mineralization in Acrisol-10 and Acrisol-100 soils at both addition rates with no effect observed for the Ferralsol. In contrast, gross nitrification was stimulated in only one soil but only at a 4% application rate. Also, biochar effects on increased NH$_{4}$$^{+}$ immobilization and NO$_{3}$$^{-}$−consumption strongly varied across the three investigated soils. The variable and bidirectional biochar effects on gross N turnover in conjunction with the unambiguous and consistent reduction of N$_{2}$O emissions suggested that the inhibiting effect of biochar on soil N$_{2}$O emission seemed to be decoupled from gross microbial N turnover processes. With biochar application, N$_{2}$ emissions were about an order of magnitude higher for Acrisol-10 soils compared to Acrisol-100 and Ferralsol-100 soils. Our N$_{2}$O and N$_{2}$ flux data thus support an explanation of direct promotion of gross N2O reduction by biochar rather than effects on soil extractable N dynamics. Effects of biochar on soil extractable N and gross N turnover, however, might be highly variable across different soils as found here for three typical agricultural soils of Kenya

Regional pragmatic variation in the use of the discourse marker pues in informal talk among university students in Quito (Ecuador), Santiago (Chile) and Seville (Spain)

The discourse marker pues in spoken Spanish has been studied extensively in Peninsular Spanish (cf. Fuentes Rodríguez 1987; Portolés 1989; Garcés Gómez 1992). There is also a growing body of studies on pues in Latin American varieties of Spanish (cf. Zavala 2001; Travis 2005; Vázquez Carranza 2013). Less attention, however, has been given to this discourse marker in Chilean and Ecuadorian Spanish (cf. Poblete 1998; Olbertz 2013). Taking a variational pragmatics perspective (Schneider and Barron 2008; Placencia 2011; Schneider and Placencia forthcoming), this paper examines the impact of region in the use of pues among university students in Quito (Ecuador), Santiago (Chile) and Seville (Spain). It is based on a corpus of 60 role-play interactions within each location eliciting advice-giving and complaint talk in –SD (social distance) –P (power) scenarios. The paper looks at variation in relation to form, position and distribution relating to turns and sections of the conversations. It also looks at the function of pues across data sets, noting its use as both a connector and an operator (Fuentes Rodríguez 2003, 2009), and thus highlighting the close interconnection between position and discursive function. Some shared features as well as features of variation were observed. Concerning function, for example, pues was found to occur as both a connector and an operator across varieties; however, we found a clear preponderance of pues as an operator in Quito and Santiago, and of pues as a connector in Seville