A Note on the Superstring BRST Operator

We write the BRST operator of the N=1 superstring as $Q= e^{-R} (\oint dz \gamma^2 b)e^R$ where $\gamma$ and $b$ are super-reparameterization ghosts. This provides a trivial proof that $Q$ is nilpotent.Comment: 4 pages late

Limited complementarity of functional and taxonomic diversity in Chilean benthic marine invertebrates

Aim Patterns of benthic biodiversity at the macroecological scale remain poorly characterised throughout the Chilean latitudinal gradient, in part due to the lack of integrated databases, uneven sampling effort, and the use of species richness alone to quantify biodiversity. Different diversity measures, encompassing taxonomic and functional components, may give us extra information on biodiversity relevant to conservation planning and management. Thus, evaluating the spatial complementarity of these measures is essential. Location Coast and continental shelf of Chile. Methods The latitudinal gradient of Chile was divided into five ecoregions according to the Marine Ecosystems of the World classification. Using a 55 × 55 km equal area grid, we estimated the incidence coverage-based estimator (ICE), taxonomic distinctness (Δ+) and three measures of functional diversity: functional richness (FRic), functional evenness (FEve) and functional divergence (FDiv). For each measure, we described spatial patterns, identified hotspots, evaluated hotspot congruence and evaluated complementarity between measures. Results Diversity patterns varied between ecoregions and over the latitudinal gradient. ICE and Δ+ peaked in the Chiloense and Channels and Fjords ecoregions. Δ+ and FRic present a similar pattern at mid-latitudes. FEve showed a contrary pattern, principally with FRic. Areas with high numbers of hotspots differed spatially according to each metric, and three latitudinal bands were observed. ICE, Δ+ and FRic were positively correlated, but the hotspot overlap at the grid cell level was more limited. Main Conclusions The complementarity between taxonomic and functional diversity measures is limited when we observe the overlap between grid cells representing hotspots. However, some regions are consistently identified as highly diverse, with the Magellanic Province (Chiloense and Channels and Fjords ecoregions) being the most important for the richness, taxonomic and functional diversity of benthos. Confirmation of the importance of this region can help prioritise conservation efforts

The Prevalence and Reasons for Interruption of Antituberculosis Treatment by Patients at Mbekweni Health Centre in King Sabata Dalidyebo (KSD) District in the Eastern Cape Province

Background: In spite of effective therapy, tuberculosis (TB) is still a major health problem in developing countries. In 1993, therefore, the World Health Organization declared TB a global emergency. In South Africa, TB is one of the most prevalent diseases, with an incidence of 556 per 100 000 population. In spite of free TB drugs in the public service and the directly observed treatment short course (DOTS) strategies, there is still a high prevalence of TB and a high treatment interruption rate in rural South Africa. Methods: The objectives of this study were to establish the prevalence of TB and reasons for the interruption of TB treatment by patients attending Mbekweni Health Centre in King Sabata Dalidyebo (KSD) district in the Eastern Cape province. This was a cross- sectional study in which data were collected from 15 July 2004 to 15 January 2005 from patients who were on TB treatment and interrupted their treatment between 6 August 2001 and 30 December 2003. Results: Of the 255 TB patients who attended for treatment, 121 (47.5%) had interrupted their treatment. Reasons given for interrup- tion included change of living place (18.96%), no money to go to the clinic (15.52%), feeling better (13.78%), side effects of the drug (6.90%), did not know the treatment course (5.17%), physical disability either old or too sick to collect treatment and nobody to help (5.17%), clinic too far (1.73%), drug not available in the clinic (13.83%) and no reasons (8.62%). Conclusion: The prevalence of treatment interruption was high in this study. Change of living place, lack of money for visiting the clinic to collect treatment, feeling better, and no drugs at the clinic were the major reasons given for interruption of treatment. Ensuring the availability of TB drugs at the health centre/clinic, patient education about TB and strengthening the DOTS programme, including a stipend for the DOTS supervisors, would help to reduce the prevalence of treatment interruption. South African Family Practice Vol. 50 (6) 2008: pp. 47-47

Massive torsion modes, chiral gravity, and the Adler-Bell-Jackiw anomaly

Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin 1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter term which is the Samuel-Jacobson-Smolin action of chiral gravity in four dimensions.Comment: 7 pages, RevTeX fil

ELKO Spinor Fields: Lagrangians for Gravity derived from Supergravity

Dual-helicity eigenspinors of the charge conjugation operator (ELKO spinor fields) belong -- together with Majorana spinor fields -- to a wider class of spinor fields, the so-called flagpole spinor fields, corresponding to the class-(5), according to Lounesto spinor field classification based on the relations and values taken by their associated bilinear covariants. There exists only six such disjoint classes: the first three corresponding to Dirac spinor fields, and the other three respectively corresponding to flagpole, flag-dipole and Weyl spinor fields. Using the mapping from ELKO spinor fields to the three classes Dirac spinor fields, it is shown that the Einstein-Hilbert, the Einstein-Palatini, and the Holst actions can be derived from the Quadratic Spinor Lagrangian (QSL), as the prime Lagrangian for supergravity. The Holst action is related to the Ashtekar's quantum gravity formulation. To each one of these classes, there corresponds a unique kind of action for a covariant gravity theory. Furthermore we consider the necessary and sufficient conditions to map Dirac spinor fields (DSFs) to ELKO, in order to naturally extend the Standard Model to spinor fields possessing mass dimension one. As ELKO is a prime candidate to describe dark matter and can be obtained from the DSFs, via a mapping explicitly constructed that does not preserve spinor field classes, we prove that in particular the Einstein-Hilbert, Einstein-Palatini, and Holst actions can be derived from the QSL, as a fundamental Lagrangian for supergravity, via ELKO spinor fields. The geometric meaning of the mass dimension-transmuting operator - leading ELKO Lagrangian into the Dirac Lagrangian - is also pointed out, together with its relationship to the instanton Hopf fibration.Comment: 11 pages, RevTeX, accepted for publication in Int.J.Geom.Meth.Mod.Phys. (2009

Primary care morbidity in Eastern Cape Province

Background. Primary health care in rural South Africa is predominantly provided by remote clinics and health centres. In 1994, health centres were upgraded and new health centres developed to serve as a health care filter between community clinics and district hospitals.Aim. To describe the spectrum of clinical problems encountered at a new health centre in an area of high economic deprivation and compare this with an adjacent community clinic and district hospital.Design. Cross-sectional survey.Setting. A rural clinic, health centre and district hospital in Eastern Cape Province, South Africa.Methods. The International Classification of Primary Care-2(ICPC-2) was used to code data collected over a 13-week period from patients presenting at a community clinic, health centre and district hospital.Results. Altogether, 4 383 patient encounters were recorded across all three sites. Most contacts at the clinic (97%) and the health centre (80%) were with a nurse. Females over 15 years of age comprised over half of all contacts at health facilities (53%). The most common diagnosis category was respiratory (23%). Cough was the most common symptom.Thirty per cent of children up to 5 years of age were seen for immunisations. Most childhood immunisations (79%) werecarried out at the health centre.Conclusion. Of all the health care facilities surveyed, the health centre had the highest throughput of patients, indicating that the health centre is an efficient filter between the community and hospital. The ICPC-2 can be successfully used to monitor encounters at similar African health care facilities.S Afr Med J 2010; 100: 309-312

[Accepted Manuscript] Psychometric Evaluation of the Adolescent Health Promotion Scale in Chile: Differences by Socioeconomic Status and Gender.

The promotion of healthy behaviors is a relevant issue worldwide, especially among adolescent populations, as this is the developmental stage where most unhealthy behaviors become ingrained. The aim of this study was to analyze the psychometric properties of the Spanish version of the Adolescent Health Promotion Scale (AHPS) in a Chilean sample of early adolescents. The sample was composed of 1,156 adolescents aged 10-14 years from schools in San Felipe, Chile. Item structure was assessed using exploratory and confirmatory factor analyses; reliability was measured using Cronbach's alpha; and differences in terms of gender, age, and socioeconomic status (SES) were established using analysis of variance. The analyses of item structure identified all of the six original factors (nutrition behaviors, health responsibility, social support, life appreciation, stress management and exercise behavior) as significant. However, eight items did not fit the Chilean population well. Therefore, the AHPS in Chile has been reduced to 32 items. The Cronbach's alpha of the 32-item Chilean AHPS was .95, with the subscale coefficients ranging from .76 to .94. In addition, female subjects performed better than male subjects, and individuals of higher SES scored higher than the middle and lower socioeconomic groups. No differences on AHPS scores were found in different age groups. The AHPS appears to have good psychometric properties in terms of item structure and reliability. Consistent with studies carried out in other countries, health promotion behavioral differences were observed in association with gender and SES. The results support the Chilean version of the AHPS as an appropriate instrument for measuring the health promotion behaviors of early adolescents in Chile and for comparing results with those from other countries

Kappa-symmetric Derivative Corrections to D-brane Dynamics

We show how the superembedding formalism can be applied to construct manifestly kappa-symmetric higher derivative corrections for the D9-brane. We also show that all correction terms appear at even powers of the fundamental length scale $l$. We explicitly construct the first potential correction, which corresponds to the kappa-symmetric version of the $\partial^4 F^4$, which one finds from the four-point amplitude of the open superstring.Comment: 20 pages. Minor changes, added reference

Pure Spinor Approach to Type IIA Superstring Sigma Models and Free Differential Algebras

This paper considers the Free Differential Algebra and rheonomic parametrization of type IIA Supergravity, extended to include the BRS differential and the ghosts. We consider not only the ghosts lambda's of supersymmetry but also the ghosts corresponding to gauge and Lorentz transformations. In this way we can derive not only the BRS transformations of fields and ghosts but also the standard pure spinor constraints on lambda's. Moreover the formalism allows to derive the action for the pure spinor formulation of type IIA superstrings in a general background, recovering the action first obtained by Berkovits and Howe.Comment: 1+23 pages, v2: added clarifications and a reference, misprints corrected, v3: presentation improved, results unchange