897 research outputs found
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
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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 inhibitorâloaded 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) inhibitorâloaded 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 inhibitorâloaded nanoparticles can produce therapeutic levels of long-term engraftment and could therefore allow single-step prenatal treatment of congenital hematological disorders
AlteraçÔes nos parùmetros fisiológicos dos recém-nascidos sob oxigenoterapia na coleta de gasometria
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
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 CiĂȘncia 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
Impact assessment of an intervention on the consumption of fruits and vegetables by students and teachers
Evaluation of employees in public day care centers knowledge about breastfeeding and complementary feeding
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