The variation of G in a negatively curved space-time

Scalar-tensor (ST) gravity theories provide an appropriate theoretical framework for the variation of Newton's fundamental constant, conveyed by the dynamics of a scalar-field non-minimally coupled to the space-time geometry. The experimental scrutiny of scalar-tensor gravity theories has led to a detailed analysis of their post-newtonian features, and is encapsulated into the so-called parametrised post-newtonian formalism (PPN). Of course this approach can only be applied whenever there is a newtonian limit, and the latter is related to the GR solution that is generalized by a given ST solution under consideration. This procedure thus assumes two hypothesis: On the one hand, that there should be a weak field limit of the GR solution; On the other hand that the latter corresponds to the limit case of given ST solution. In the present work we consider a ST solution with negative spatial curvature. It generalizes a general relativistic solution known as being of a degenerate class (A) for its unusual properties. In particular, the GR solution does not exhibit the usual weak field limit in the region where the gravitational field is static. The absence of a weak field limit for the hyperbolic GR solution means that such limit is also absent for comparison with the ST solution, and thus one cannot barely apply the PPN formalism. We therefore analyse the properties of the hyperbolic ST solution, and discuss the question o defining a generalised newtonian limit both for the GR solution and for the purpose of contrasting it with the ST solution. This contributes a basic framework to build up a parametrised pseudo-newtonian formalism adequate to test ST negatively curved space-times.Comment: 7 pages, 5 figures. Contribution to the Joint European and National Astronomy Meeting (JENAM) 2010; based on a talk given by JPM in the "From Varying Couplings to Fundamental Physics" Symposiu

Cleavage of an engulfment peptidoglycan hydrolase by a sporulation signature protease in <em>Clostridioides difficile</em>

\ua9 2024 The Author(s). Molecular Microbiology published by John Wiley &amp; Sons Ltd.In the model organism Bacillus subtilis, a signaling protease produced in the forespore, SpoIVB, is essential for the activation of the sigma factor σK, which is produced in the mother cell as an inactive pro-protein, pro-σK. SpoIVB has a second function essential to sporulation, most likely during cortex synthesis. The cortex is composed of peptidoglycan (PG) and is essential for the spore\u27s heat resistance and dormancy. Surprisingly, the genome of the intestinal pathogen Clostridioides difficile, in which σK is produced without a pro-sequence, encodes two SpoIVB paralogs, SpoIVB1 and SpoIVB2. Here, we show that spoIVB1 is dispensable for sporulation, while a spoIVB2 in-frame deletion mutant fails to produce heat-resistant spores. The spoIVB2 mutant enters sporulation, undergoes asymmetric division, and completes engulfment of the forespore by the mother cell but fails to synthesize the spore cortex. We show that SpoIIP, a PG hydrolase and part of the engulfasome, the machinery essential for engulfment, is cleaved by SpoIVB2 into an inactive form. Within the engulfasome, the SpoIIP amidase activity generates the substrates for the SpoIID lytic transglycosylase. Thus, following engulfment completion, the cleavage and inactivation of SpoIIP by SpoIVB2 curtails the engulfasome hydrolytic activity, at a time when synthesis of the spore cortex peptidoglycan begins. SpoIVB2 is also required for normal late gene expression in the forespore by a currently unknown mechanism. Together, these observations suggest a role for SpoIVB2 in coordinating late morphological and gene expression events between the forespore and the mother cell

Childbirth care: the oral history of women who gave birth from the 1940s to 1980s

This study's objective was to gain a greater understanding of the changes that took place in the childbirth care model from the experience of women who gave birth in the State of Sao Paulo, Brazil from the 1940s to the 1980s. This is a descriptive study conducted with 20 women using the Thematic Oral History method. Data were collected through unstructured interviews. The theme extracted from the interviews was "The experience of childbirth". The results indicate a time and generational demarcation in the 1970s. Childbirths from 1940 to 1960 occurred in a context of transition from home to hospital births. The 1980s represents a turning point in the elements that compose the childbirth care model, such as the type and place of birth and the professional assisting women, with an increased use of technology and obstetric interventions

Donor cell engineering with GSK3 inhibitor–loaded nanoparticles enhances engraftment after in utero transplantation

Host cell competition is a major barrier to engraftment after in utero hematopoietic cell transplantation (IUHCT). Here we describe a cell-engineering strategy using glycogen synthase kinase-3 (GSK3) inhibitor–loaded nanoparticles conjugated to the surface of donor hematopoietic cells to enhance their proliferation kinetics and ability to compete against their fetal host equivalents. With this approach, we achieved remarkable levels of stable, long-term hematopoietic engraftment for up to 24 weeks post-IUHCT. We also show that the salutary effects of the nanoparticle-released GSK3 inhibitor are specific to donor progenitor/stem cells and achieved by a pseudoautocrine mechanism. These results establish that IUHCT of hematopoietic cells decorated with GSK3 inhibitor–loaded nanoparticles can produce therapeutic levels of long-term engraftment and could therefore allow single-step prenatal treatment of congenital hematological disorders

Duke Surgery Patient Safety: an open-source application for anonymous reporting of adverse and near-miss surgical events

BACKGROUND: Studies have shown that 4% of hospitalized patients suffer from an adverse event caused by the medical treatment administered. Some institutions have created systems to encourage medical workers to report these adverse events. However, these systems often prove to be inadequate and/or ineffective for reviewing the data collected and improving the outcomes in patient safety. OBJECTIVE: To describe the Web-application Duke Surgery Patient Safety, designed for the anonymous reporting of adverse and near-miss events as well as scheduled reporting to surgeons and hospital administration. SOFTWARE ARCHITECTURE: DSPS was developed primarily using Java language running on a Tomcat server and with MySQL database as its backend. RESULTS: Formal and field usability tests were used to aid in development of DSPS. Extensive experience with DSPS at our institution indicate that DSPS is easy to learn and use, has good speed, provides needed functionality, and is well received by both adverse-event reporters and administrators. DISCUSSION: This is the first description of an open-source application for reporting patient safety, which allows the distribution of the application to other institutions in addition for its ability to adapt to the needs of different departments. DSPS provides a mechanism for anonymous reporting of adverse events and helps to administer Patient Safety initiatives. CONCLUSION: The modifiable framework of DSPS allows adherence to evolving national data standards. The open-source design of DSPS permits surgical departments with existing reporting mechanisms to integrate them with DSPS. The DSPS application is distributed under the GNU General Public License

Maternal and neonatal factors related to prematurity

ABSTRACT OBJECTIVE To identify maternal and neonatal factors associated with prematurity in the municipality of Porto Alegre. METHOD This was a population-based case-control study. The cases were newborns under 37 weeks of gestation and the controls were newborns over 37 weeks. The data came from the records of 19,457 births in the city of Porto Alegre in the year 2012 from the Information System on Live Births of the Municipal Health Department. The analysis was carried outand adjusted by a Logistic Regression according to a hierarchical model. The variables studied were allocated into three hierarchy levels: sociodemographic variables; reproductive history; and gestational and birth factors. RESULTS There were 767 cases allocated and 1,534 controls in a design of a case for two controls (1:2) by simple randomization. In the final model, a statistically significant association was found for prematurity for the following variables: mother's age under 19 years old (OR=1.32; CI 95%: 1.02-1.71) or over 34 years old (OR=1.39; CI 95%: 1.12-1.72); inadequate maternal schooling for age (OR=2.11; CI 95%: 1.22-3.65); multiple pregnancies (OR=1.14; CI 95%: 1.01-1.29); C-section (OR=1.15; CI 95%: 1.03-1.29); birth weights under 2,500g (OR=4.04; CI 95%: 3.64-4.49); Apgar score at five minutes between zero and three (OR=1.47; CI 95%: 1.12-1.91); and inadequate prenatal care (OR=1.18; CI 95%: 1.02-1.36). CONCLUSION The present study showed the most immediate consequence of prematurity for newborns by evidencing its association with worse Apgar scores and low birth weight. The following factors were also shown as possible more distal determinants of prematurity: mother's age; inadequate maternal education; multiple gestation; inadequate prenatal care; and C-section

Presence of extracellular DNA in the Candida albicans biofilm matrix and its contribution to biofilms

DNA has been described as a structural component of the extracellular matrix (ECM) in bacterial biofilms. In Candida albicans, there is a scarce knowledge concerning the contribution of extracellular DNA (eDNA) to biofilm matrix and overall structure. This work examined the presence and quantified the amount of eDNA in C. albicans biofilm ECM and the effect of DNase treatment and the addition of exogenous DNA on C. albicans biofilm development as indicators of a role for eDNA in biofilm development. We were able to detect the accumulation of eDNA in biofilm ECM extracted from C. albicans biofilms formed under conditions of flow, although the quantity of eDNA detected differed according to growth conditions, in particular with regards to the medium used to grow the biofilms. Experiments with C. albicans biofilms formed statically using a microtiter plate model indicated that the addition of exogenous DNA (>160 ng/ml) increases biofilm biomass and, conversely, DNase treatment (>0.03 mg/ml) decreases biofilm biomass at later time points of biofilm development. We present evidence for the role of eDNA in C. albicans biofilm structure and formation, consistent with eDNA being a key element of the ECM in mature C. albicans biofilms and playing a predominant role in biofilm structural integrity and maintenance.National Institute of Dental & Craniofacial ResearchFundação para a Ciência e Tecnologia (FCT) - SFRH/BD/28222/2006National Institute of Allergy and Infectious Disease

f(R) theories

Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom