Relating Weyl and diffeomorphism anomalies on super Riemann surfaces

Starting from the Wess-Zumino action associated to the super Weyl anomaly, we determine the local counterterm which allows to pass from this anomaly to the chirally split superdiffeomorphism anomaly (as defined on a compact super Riemann surface without boundary). The counterterm involves the graded extension of the Verlinde functional and the results can be applied to the study of holomorphic factorization of partition functions in superconformal field theory.Comment: (LATEX, 18 pages), MPI-Ph/92-38, LPTB 92-

Nitrogen isotopic evolution of carbonaceous matter during metamorphism: Methodology and preliminary results

Nitrogen content and isotopic composition of carbonaceous-rich metasediments were determined by on-line and sealed-tube combustion using ultra-high vacuum line and static mass spectrometer adapted to analyse nitrogen nanomoles. Accurate measurements showed that nitrogen amount released by on-line combustion technique was underestimated to various extents. As a result, the nitrogen isotopic composition was not correctly determined. In contrast, sealed-tube combustion appeared to yield the most reproducible and accurate measurements, except for nitrogen depleted carbonaceous matter (semi-graphite to graphite transition) containing less than around 60 ppm of nitrogen, which were contaminated during their extraction from the rock. In view of that, a preliminary sealed-tube investigation of the organic nitrogen content and isotopic composition in a homogenous series of low-grade metasediments was undertaken: in spite of an important nitrogen loss, the carbonaceous matter nitrogen isotopic composition remains about the same during the meta-anthracite and semi-graphitisation stages. Inferences on the process of organic nitrogen mineralization during carbonaceous matter metamorphism can be drawn and several paleo-biogeochemical implications envisaged

Consistent anomalies of the induced W gravities

The BRST anomaly which may be present in the induced $W_n$ gravity quantized on the light-cone is evaluated in the geometrical framework of Zucchini. The cocycles linked by the cohomology of the BRST operator to the anomaly are straightforwardly calculated thanks to the analogy between this formulation and the Yang-Mills theory. We give also a conformally covariant formulation of these quantities including the anomaly, which is valid on arbitrary Riemann surfaces. The example of the $W_3$ theory is discussed and a comparison with other candidates for the anomaly available in the literature is presented.Comment: Latex, no figures, 12 pages (To appear on Physics Letters B.

Where do Smallholder Farmers get Their Information? An Exploration of the Sources of Agricultural Information in Northwest Cambodia.

A significant emphasis on scaling up food security efforts is needed to achieve Sustainable Development Goal 2 (Zero Hunger) by 2030. Scaling up sustainable intensification efforts for Cambodian smallholder farmers is key since they face greater exposure to the uncertainties of climate change, globalizing markets, and rural-to-urban migration. One way to increase the effectiveness of efforts and the scaling up of sustainable intensification technologies is through improving access to information about production and marketing technologies. This study aimed to identify sources of information about sustainable technologies available to smallholders and barriers that may be preventing adoption. Information was gathered from a household survey to document the sources of agricultural information for smallholders in Northwest Cambodia. This research suggests Cambodian smallholders are receiving agricultural extension services, however, the overall quality and effectiveness of these messages are unknown, since NGOs with competing foci are the primary provider of extension information. Smallholders face significant barriers that prevent the adoption of sustainable technologies and participation in markets, such as low price for goods, poor product quality, lack of time, and concerns for safety. Future endeavors to strengthen the price of goods and alleviate market-related challenges would likely result in increased smallholder income and food availability

Induced Polyakov supergravity on Riemann surfaces of higher genus

An effective action is obtained for the $N=1$, $2D-$induced supergravity on a compact super Riemann surface (without boundary) $\hat\Sigma$ of genus $g>1$, as the general solution of the corresponding superconformal Ward identity. This is accomplished by defining a new super integration theory on $\hat\Sigma$ which includes a new formulation of the super Stokes theorem and residue calculus in the superfield formalism. Another crucial ingredient is the notion of polydromic fields. The resulting action is shown to be well-defined and free of singularities on \sig. As a by-product, we point out a morphism between the diffeomorphism symmetry and holomorphic properties.Comment: LPTB 93-10, Latex file 20 page

Supersymmetric structure of the induced W gravities

We derive the supersymmetric structure present in W-gravities which has been already observed in various contexts as Yang-Mills theory, topological field theories, bosonic string and chiral W_{3}-gravity. This derivation which is made in the geometrical framework of Zucchini, necessitates the introduction of an appropriate new basis of variables which replace the canonical fields and their derivatives. This construction is used, in the W_{2}-case, to deduce from the Chern-Simons action the Wess-Zumino-Polyakov action.Comment: 17 pages, Latex. To appear in Class. Quantum. Gravit

A geometrical approach to super W-induced gravities in two dimensions

A geometrical study of supergravity defined on (1|1) complex superspace is presented. This approach is based on the introduction of generalized superprojective structures extending the notions of super Riemann geometry to a kind of super W-Riemann surfaces. On these surfaces a connection is constructed. The zero curvature condition leads to the super Ward identities of the underlying supergravity. This is accomplished through the symplectic form linked to the (super)symplectic manifold of all super gauge connections. The BRST algebra is also derived from the knowledge of the super W-symmetries which are the gauge transformations of the vector bundle canonically associated to the generalized superprojective structures. We obtain the possible consistent BRST (super)anomalies and their cocycles related by the descent equations. Finally we apply our considerations to the case of supergravity.Comment: 29 pages, latex, no figures, to appear in Nucl. Phys.

BMJ Med

OBJECTIVE: To evaluate the efficacy of covid-19 convalescent plasma to treat patients admitted to hospital for moderate covid-19 disease with or without underlying immunodeficiency (CORIPLASM trial). DESIGN: Open label, randomised clinical trial. SETTING: CORIMUNO-19 cohort (publicly supported platform of open label, randomised controlled trials of immune modulatory drugs in patients admitted to hospital with moderate or severe covid-19 disease) based on 19 university and general hospitals across France, from 16 April 2020 to 21 April 2021. PARTICIPANTS: 120 adults (n=60 in the covid-19 convalescent plasma group, n=60 in the usual care group) admitted to hospital with a positive SARS-CoV2 test result, duration of symptoms 40. MAIN OUTCOME MEASURES: Primary outcomes were proportion of patients with a WHO Clinical Progression Scale score of ≥6 on the 10 point scale on day 4 (higher values indicate a worse outcome), and survival without assisted ventilation or additional immunomodulatory treatment by day 14. Secondary outcomes were changes in WHO Clinical Progression Scale scores, overall survival, time to discharge, and time to end of dependence on oxygen supply. Predefined subgroups analyses included immunosuppression status, duration of symptoms before randomisation, and use of steroids. RESULTS: 120 patients were recruited and assigned to covid-19 convalescent plasma (n=60) or usual care (n=60), including 22 (covid-19 convalescent plasma) and 27 (usual care) patients who were immunocompromised. 13 (22%) patients who received convalescent plasma had a WHO Clinical Progression Scale score of ≥6 at day 4 versus eight (13%) patients who received usual care (adjusted odds ratio 1.88, 95% credible interval 0.71 to 5.24). By day 14, 19 (31.6%) patients in the convalescent plasma group and 20 (33.3%) patients in the usual care group needed ventilation, additional immunomodulatory treatment, or had died. For cumulative incidence of death, three (5%) patients in the convalescent plasma group and eight (13%) in the usual care group died by day 14 (adjusted hazard ratio 0.40, 95% confidence interval 0.10 to 1.53), and seven (12%) patients in the convalescent plasma group and 12 (20%) in the usual care group by day 28 (adjusted hazard ratio 0.51, 0.20 to 1.32). In a subgroup analysis performed in patients who were immunocompromised, transfusion of covid-19 convalescent plasma was associated with mortality (hazard ratio 0.39, 95% confidence interval 0.14 to 1.10). CONCLUSIONS: In this study, covid-19 convalescent plasma did not improve early outcomes in patients with moderate covid-19 disease. The efficacy of convalescent plasma in patients who are immunocompromised should be investigated further. TRIAL REGISTRATION: ClinicalTrials.gov NCT04345991

Thickness dependence of second-order magnetic phase transitions in films

Using a simple Landau model, we discuss the different possibilities of generating near-surface magnetic effects at a second-order transition for films. For experimental comparison, we define an order parameter averaged on the film thickness. Varying the sample size d and/or surface coupling γ , one can decrease or increase substantially the surface critical temperature Ts and the saturation magnetizationMs . In the case ofγ >0, bothMs and Ts decrease from the bulk values as the film thickness is reduced. These theoretical results are, in particular, in nice agreement with the experimental data on superconducting MgB2 thin films. By contrast, forγ >0, an enhancement of both quantities is expected. This extraordinary transition has been rarely observed experimentally and usually the situation is far from been clear. We analyze a new experiment on NiFe2O4 ultra-thin films, where a very strong enhancement of Ms is observed