525 research outputs found
The SU(2) Skyrme model and anomaly
The SU(2) Skyrme model,expanding in the collective coordinates variables,
gives rise to second-class constraints. Recently this system was embedded in a
more general Abelian gauge theory using the BFFT Hamiltonian method. In this
work we quantize this gauge theory computing the Noether current anomaly using
for this two different methods: an operatorial Dirac first class formalism and
the non-local BV quantization coupled with the Fujikawa regularization
procedure.Comment: 6 pages, Revtex. Final version to be published in Physics Letters
Efficacy and safety of pharmacological interventions for managing sickle cell disease in children and adolescents: protocol for a systematic review with network meta-analysis
IntroductionSickle cell disease (SCD), an inherited haemoglobinopathy, has important impact on morbidity and mortality, especially in paediatrics. Previous systematic reviews are limited to adult patients or focused only on few therapies. We aim to synthesise the evidence on efficacy and safety of pharmacological interventions for managing SCD in children and adolescents.Methods and analysisThis systematic review protocol is available at Open Science Framework (doi:10.17605/OSF.IO/CWAE9). We will follow international recommendations on conduction and report of systematic reviews and meta-analyses. Searches will be conducted in PubMed, Scopus and Web of Science (no language nor time restrictions) (first pilot searches performed in May 2022). We will include randomised controlled trials comparing the effects of disease-modifying agents in patients with SCD under 18 years old. Outcomes of interest will include: vaso-occlusive crisis, haemoglobin levels, chest syndrome, stroke, overall survival and adverse events. We will provide a narrative synthesis of the findings, and whenever possible, results will be pooled by means of pairwise or Bayesian network meta-analyses with surface under the cumulative ranking curve analyses. Different statistical methods and models will be tested. Dichotomous outcomes will be reported as OR, risk ratio or HR, while continuous data will be reported as standard mean differences, both with 95% CI/credibility interval. The methodological quality of the trials will be evaluated using the Risk of Bias 2.0 tool, and the certainty of the evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation approach.Ethics and disseminationThis study refers to a systematic review, so no ethics approval is necessary. We intent to publish our findings in international, peer-reviewed journal. Data will also be presented to peers in scientific events. Additionally, the results obtained in this study may contribute towards the update of therapeutic guidelines and for the development of health policies for SCD.PROSPERO registration numberCRD42022328471.</jats:sec
Free Differential Algebras and Pure Spinor Action in IIB Superstring Sigma Models
In this paper we extend to the case of IIB superstring sigma models the
method proposed in hep-th/10023500 to derive the pure spinor approach for type
IIA sigma models. In particular, starting from the (Free) Differential Algebra
and superspace parametrization of type IIB supergravity, extended to include
the BRST differential and all the ghosts, we derive the BRST transformations of
fields and ghosts as well as the standard pure spinor constraints for the
ghosts related to supersymmetry. Moreover, using the method first
proposed by us, we derive the pure spinor action for type IIB superstrings in
curved supergravity backgrounds (on shell), in full agreement with the action
first obtained by Berkovits and Howe.Comment: 24 page
Prevalence of rheumatoid arthritis in South America: a systematic review and meta-analysis
Rheumatoid arthritis (RA) is among the most prevalent chronic autoimmune and inflammatory diseases worldwide. The aim of this study was to establish a pooled estimate of the RA prevalence in South America by means of a meta-analysis of the available epidemiologic studies. Systematic searches in PubMed, Lilacs, SciELO, Scopus, and Web of Science databases (updated May 2019) were done followed by a systematic grey literature search to identify original research articles and reports, published after 2000, providing data of RA prevalence in any South American country. Proportion meta-analysis of weighted pooled was performed, with between-trial heterogeneity assessed by the inconsistency relative index. Sensitivity analyses and sub-group analyses were also done. A total of 25 articles, representing 27 population-based studies were included. Pooled prevalence of RA resulted in 0.48% with 591,981 cases in a population of 114,537,812 individuals (I2=99%). Brazil and Colombia presented the lowest rates of RA prevalence 0.22%, and 0.24%, respectively. RA prevalence in indigenous population was higher 1.45%, and studies using COPCORD method reported also the highest rates 1.07%
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
Use of electrical bioimpedance analysis to evaluate the quality of bovine raw milk
The objective of the present study was to use electrical bioimpedance analysis (BIA) as an alternative method of evaluating the quality of bovine raw milk. Fourteen lactating purebred Dutch cows were used. For the analyses of milk quality and electrical bioimpedance, 140 ml milk per mammary quarter and a homogeneous sample of each animal were collected, totalling 70 samples. The criteria used to evaluate milk quality consisted of somatic cell count (CCS), total bacterial count (CBT), fat, protein, lactose, total solids (ST) and non-greasy solids (SNG) as required by IN No 62/2011. A monofrequential 50 kHz and 800 μA alternating current generator was used for electrical BIAs. The temperature of the raw milk was 5 °C for all samples. Primary resistance and reactance readings were obtained. From these values, the values of impedance, conductance and phase angle were obtained. Correlation analyses were performed to determine the variables used by the regression analyses. The regression analysis was performed using raw milk components as dependent variables and BIA measurements as independent variables. Lactose, ST and SNG were the components of milk that correlated best and presented moderate prediction equations in relation to BIA variables. The prediction equations using resistance showed R2 of 0.42 and 0.45 for ST and SNG, respectively. In the prediction equation for ST and SNG, the conductance resulted in R2 of 0.45, and 0.45, respectively. Regarding impedance, the R2 of 0.42 and 0.45 were obtained for the predicted equations ST and SNG, respectively. Thus, it can be concluded that BIA has the potential to estimate the composition and quality of bovine raw milk.Keywords: conductance, impedance, milk compositio
Taxonomic resolution refinement does not improve understanding of invertebrate's role on leaf litter breakdown
Abstract
The invertebrate biodiversity of subtropical streams depends on the seasonal input of organic matter, as much as the leaf decomposition process on stream system. However, one of the challenges in determining the importance of invertebrates for leaf breakdown in subtropical streams is the low taxonomic resolution applied in most studies. To overcome this limitation, here we used litter bags with senescent leaves to evaluate the impact of different taxonomic resolutions of trophic group classification to assess the seasonal importance of invertebrate community for leaf litter breakdown in a subtropical stream (Atlantic Forest in western of Paraná state, Brazil). Litterfall was quarterly measured over a year. The leaf litter accumulated in an interval of 30 days was retrieved, weighed, and used for the leaf breakdown experiments (by litter bags). We found a lower importance of invertebrate community richness and density (shredders and scrapers) in leaf breakdown process irrespective of the taxonomic resolution (family or genus level used). Hyphomycetes biomass and fungi sporulation also did not present changes among sample times, and consecutively, importance for leaf breakdown. However, the richness and density of Chironomidae taxa respond differently depending on the taxonomic resolution used. Low litter breakdown may be explained by the increase of consumption of microorganisms, due to high density of Chironomidae scrapers evaluated at the genus level. Moreover, temperature is the main factor responsible for breakdown over the year, in a positive way. Therefore, our results indicated the family level as the taxonomic resolution sufficient to assess the role of shredders and scrapers in the leaf litter breakdown process of this subtropical stream system
Implications of a defined daily dose fixed database for drug utilization research studies: The case of statins in Portugal
Aims Given the discrepancies between PDDs (prescribed daily doses) and DDDs (defined daily doses), we aimed to assess the extent of error in the results of an 18-year population-level study on statin utilization in Portugal. Methods The Portuguese regulatory agency provided data for the period 2000-2018 on statin dispensing (C10AA). The DDDs were gathered from the ATC/DDD database. DDDs were calculated by the DDD year-by-year approach (DDDYEAR) and by the DDD last-year approach (DDDLAST). PDDs were calculated according to the year-by-year approach (PDDYEAR). Statin annual utilization rates per 1000 inhabitants per day were also calculated. Percent errors were calculated for PDDYEAR and DDDYEAR units. Results The DDDYEAR approach revealed decreases in the consumption of atorvastatin, fluvastatin, lovastatin, pravastatin and simvastatin in 2009, when their DDD was modified. Conversely, the results from both DDDLAST and PDDYEAR approaches indicated gradual changes in the actual consumption of all statins in Portugal. Before 2009, atorvastatin, pravastatin and simvastatin utilization was greatly overestimated by DDDYEAR/1000 inhabitants/day. The average dose of lovastatin prescribed in the past 18 years (20 mg) was below the assigned DDDs during the study period, varying from 30 mg to 45 mg. Conversely, the PDD for fluvastatin was above the DDD values (ranging from 40 mg in 2000 to 70 mg in 2016). For atorvastatin, pravastatin and simvastatin, national PDDs were above the assigned DDD until the DDD modification in 2009. Conclusions A more dynamic system, based on national and annually updated DDDs, should be able to reduce discrepancies between DDDs and PDDs and the bias in utilization studies
Subcritical Superstrings
We introduce the Liouville mode into the Green-Schwarz superstring. Like
massive supersymmetry without central charges, there is no kappa symmetry.
However, the second-class constraints (and corresponding Wess-Zumino term)
remain, and can be solved by (twisted) chiral superspace in dimensions D=4 and
6. The matter conformal anomaly is c = 4-D < 1. It thus can be canceled for
physical dimensions by the usual Liouville methods, unlike the bosonic string
(for which the consistency condition is c = D <= 1).Comment: 9 pg., compressed postscript file (.ps.Z), other formats (.dvi, .ps,
.ps.Z, 8-bit .tex) available at
http://insti.physics.sunysb.edu/~siegel/preprints/ or at
ftp://max.physics.sunysb.edu/preprints/siege
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