First-order framework and domain-wall/brane-cosmology correspondence

AbstractWe address the possibility of finding domain wall solutions from cosmological solutions in brane cosmology. We find first-order equations for corresponding cosmology/domain wall solutions induced on 3-branes. The quadratic term of energy density in the induced Friedmann equation plays a non-standard role and we discuss the way the standard cosmological and domain wall models are recovered as the brane tension becomes large and show how they can be described by four-dimensional supergravity action in such a limit. Finally, we show that gravity on the 3-brane is locally localized as one moves away from the two-dimensional domain walls living on the brane

Reactions from family of origin to the disclosure of lesbian motherhood via donor insemination

Most studies of planned lesbian motherhood via donor insemination (DI) have sampled lesbian mothers in individualistic societies where adults have relatively distant connection to their family of origin. Our study examined the experiences of biological and non-biological lesbian mothers in five families who had children through DI after disclosing their motherhood status to their family networks in Portugal, a familistic society. The first theme identified by thematic analysis, “But why do you want to have a child?” encapsulated the reactions of biological mothers’ family of origin to the announcement of motherhood. Disclosure was mostly met by a shocked response in the extended family, rooted in the belief that lesbian women should not have children. The second theme, “But you weren’t pregnant, how is this your child?” summarized the reactions of non-biological mothers’ family of origin to the disclosure of motherhood status as they considered refusing to recognize their grandchild in the absence of biological connection. Prejudice against lesbian-mother family formation was associated with the specific intersection of lesbianism and motherhood, but relationships between the mothers and their families were largely repaired because of familistic values

Quantifying the interdisciplinarity of scientific journals and fields

There is an overall perception of increased interdisciplinarity in science, but this is difficult to confirm quantitatively owing to the lack of adequate methods to evaluate subjective phenomena. This is no different from the difficulties in establishing quantitative relationships in human and social sciences. In this paper we quantified the interdisciplinarity of scientific journals and science fields by using an entropy measurement based on the diversity of the subject categories of journals citing a specific journal. The methodology consisted in building citation networks using the Journal Citation Reports database, in which the nodes were journals and edges were established based on citations among journals. The overall network for the 11-year period (1999-2009) studied was small-world and scale free with regard to the in-strength. Upon visualizing the network topology an overall structure of the various science fields could be inferred, especially their interconnections. We confirmed quantitatively that science fields are becoming increasingly interdisciplinary, with the degree of interdisplinarity (i.e. entropy) correlating strongly with the in-strength of journals and with the impact factor.Comment: 23 pages, 6 figure

Obstetrician's risk perception on the prescription of magnesium sulfate in severe preeclampsia and eclampsia: a qualitative study in Brazil

Magnesium sulfate (MgSO4) is the drug of choice for the prevention and control of seizures in the management of severe preeclampsia/eclampsia. Several barriers have been iden-tified in the use of MgSO4, especially in low and middle-income settings. Objective To describe the obstetrician's perception on possible reasons for underutilizing magnesium sulfate to treat preeclampsia/eclampsia. Method A qualitative clinical study, based on phenomenological reference by semi-structured inter-views and open-ended discussions with obstetricians of the public healthcare system in pri-mary care units (PCU) and referral maternity hospitals (RMH), in a southeastern Brazilian city. Results Fear of drug toxicity was the major cause for not prescribing the medication in PCU. Fear was justified by insufficient technical, structural and organizational resources of healthcare facilities and by a shortage of physicians properly trained for adequate drug use. Conclusion Fear of toxicity of magnesium sulfate was the main barrier towards timely and proper drug use. Periodic skill development and training of obstetricians, along with integration of the medical team in the work environment may contribute to decrease fear, ensuring safety of drug prescription and thus possibly reducing adverse outcomes related to PE.Introduction Magnesium sulfate (MgSO4) is the drug of choice for the prevention and control of seizures in the management of severe preeclampsia/eclampsia. Several barriers have been iden-tified in the use of MgSO4, especially in low and middle-income set123sem informaçãosem informaçã

The anisotropic Ashkin-Teller model: a renormalization group study

The two-dimensional ferromagnetic anisotropic Ashkin-Teller model is investigated through a real-space renormalization-group approach. The critical frontier, separating five distinct phases, recover all the known exacts results for the square lattice. The correlation length $(\nu_T)$ and crossover $(\phi)$ critical exponents are also calculated. With the only exception of the four-state Potts critical point, the entire phase diagram belongs to the Ising universality class.Comment: 3 ps figures, accepted for publication in Physica

3D black holes on a 2-brane in 4D Minkowski space

We investigate three-dimensional black hole solutions in the realm of pure and new massive gravity in 2+1 dimensions induced on a 2-brane embedded in a flat four-dimensional spacetime. There is no cosmological constant neither on the brane nor on the four-dimensional bulk. Only gravitational fields are turned on and we indeed find vacuum solutions as black holes in 2+1 dimensions even in the absence of any cosmological solution. There is a crossover scale that controls how far the three- or four-dimensional gravity manifests on the 2-brane. Our solutions also indicate that local BTZ and SdS_3 solutions can flow to local four-dimensional Schwarzschild like black holes, as one probes from small to large distances, which is clearly a higher dimensional manifestation on the 2-brane. This is similar to the DGP scenario where the effects of extra dimensions for large probed distances along the brane manifest.Comment: 10 pages, 5 figures, to appear in PL

Correlations between climate network and relief data

In the last few years, the scientific community has witnessed an ongoing trend of using ideas developed in the study of complex networks to analyze climate dynamics. This powerful combination, usually called climate networks, can be used to uncover non-trivial patterns of weather changes throughout the years. Here we investigate the temperature network of the North American region and show that two network characteristics, namely degree and clustering, have marked differences between the eastern and western regions. We show that such differences are a reflection of the presence of a large network community on the western side of the continent. Moreover, we provide evidence that this large community is a consequence of the peculiar characteristics of the western relief of North America

Anomalous diffusion on crumpled wires in two dimensions

It is investigated the statistical properties of random walks evolving on real configurations of a crumpled wire rigidly jammed in two dimensions. These crumpled hierarchical structures with complex topology are obtained from a metallic wire injected at a constant rate into a transparent planar cell of 20cm of diameter. The observed diffusion is anomalous with an exponent very close to that obtained at the threshold of two dimensional percolation. A comparison of the system studied in this paper with other systems of physical interest is also made, and an experimental consequence of our results is discussed.Comment: 10 pages including 4 figures. Physica A (2006). Preprin