1,165 research outputs found
Positive tension 3-branes in an bulk
In this work, we review and extend the so-called consistency conditions for
the existence of a braneworld scenario in arbitrary dimensions in the
Brans-Dicke (BD) gravitational theory. After that, we consider the particular
case of a five-dimensional scenario which seems to have phenomenological
interesting implications. We show that, in the BD framework, it is possible to
achieve necessary conditions pointing to the possibility of accommodating
branes with positive tensions in an AdS bulk by the presence of the additional
BD scalar field, avoiding in this way the necessity of including unstable
objects in the compactification scheme. Furthermore, in the context of time
variable brane tension, it is shown that the brane tension may change its sign,
following the bulk cosmological constant sign.Comment: 15 pages, new version to appear in JHE
A New Association of Post-T Tauri Stars Near The Sun
Observing ROSAT sources in 20 x 25 deg centered at the high latitude active
star ER Eri, we found evidences for a new young nearby association (~30Myr
at~60pc), the Horologium Association (HorA), formed by at least 10 probable and
6 possible members, some being Post-T Tauri stars. We examine several
requirements that characterize a young association and they, together, create a
strong evidence for the reality of the HorA. In fact, the Li line intensities
are between those of the oldest classical T Tauri stars and the ones of the
Local Association stars. The space velocities of the HorA relative to the Sun,
U= -9.5+/-1.0, V = -20.9 +/- 1.1, W = -2.1 +/- 1.9, are not far from those of
the Local Association. We suggest that some hotter and non-X-ray active stars,
with similar space velocities, could be massive members of the HorA, among
them, the nearby Be star Achernar. The maximum of the mass distribution
function of the HorA is around 0.8 solar masses. At its distance, the projected
size of the HorA, ~50 pc, would be larger than our surveyed area and many other
members could have been missed. We also observed 3 control regions, two at
northern and southern galactic latitudes and a third one in the known TW Hya
Association (TWA), and the properties and distribution of their young stars
strengthen the reality of the HorA. Contrary to the TWA, the only known
binaries in the HorA are 2 very wide systems. The HorA is much more isolated
from clouds and older than the TWA and could give some clues about the lifetime
of the disks around T Tauri stars. Actually, none of the proposed members is an
IRAS source indicating an advanced stage of the evolution of their accreting
disks. ER Eri itself was found to be a RS CVn-like system.Comment: 25 pages, 5 eps figures, to appear in Astron.
Outcomes of 3,400 patients with cancer admitted to intensive care unit: a Brazilian prospective study
Renal apnoea: extreme disturbance of homoeostasis in a child with Bartter syndrome type IV
A 2-week-old girl was transferred to our renal ward in February, 2014, from the neonatal intensive care unit of her local hospital with polyuria (200 mL/kg per day) and extreme acid–base and electrolyte disturbance that had been present from birth. She was born by spontaneous delivery at 32 weeks' gestation, after a pregnancy complicated by severe polyhydramnios necessitating two amnioreductions that had removed more than 6 L of fluid. She is the third child of consanguineous parents, with no relevant family history
Australian Gay Men’s Satisfaction with Sexual Agreements: The Roles of Relationship Quality, Jealousy, and Monogamy Attitudes
Biochemical effect evaluation of perfluorooctane sulfonic acid-contaminated wood mice (Apodemus sylvaticus).
Wood mice (Apodemus sylvaticus) were captured at Blokkersdijk, a nature reserve in the immediate vicinity of a fluorochemical plant in Antwerp, Belgium, and at Galgenweel, 3 kilometers farther away. The liver perfluorooctane sulfonic acid (PFOS) concentrations in the Blokkersdijk mice were extremely high (0.47-178.55 micro g/g wet weight). Perfluorononanoic, perfluorodecanoic, perfluoroundecanoic, and perfluorododecanoic acids were found sporadically in the liver tissue of the Blokkersdijk mice. The liver PFOS concentrations at Galgenweel were significantly lower than those at Blokkersdijk (0.14-1.11 micro g/g wet weight). Further results suggest sex independence of the liver PFOS levels, increased levels of PFOS bioaccumulation in older mice, and maternal PFOS transfer to the young. Several liver end points were significantly elevated in the Blokkersdijk mice: liver weight, relative liver weight, peroxisomal beta-oxidation activity, microsomal lipid peroxidation level, and mitochondrial fraction protein content. For the mitochondrial fraction catalase activity, no significant difference between locations was found. The liver weight, relative liver weight, and liver microsomal lipid peroxidation level increased significantly with the liver PFOS concentration. No indications for PFOS-mediated effects on the serum triglyceride, cholesterol, or potassium levels were obtained. The liver PFOS concentration was negatively related to the serum alanine aminotransferase activity
Suppression of Richtmyer-Meshkov instability via special pairs of shocks and phase transitions
The classical Richtmyer-Meshkov instability is a hydrodynamic instability
characterizing the evolution of an interface following shock loading. In
contrast to other hydrodynamic instabilities such as Rayleigh-Taylor, it is
known for being unconditionally unstable: regardless of the direction of shock
passage, any deviations from a flat interface will be amplified. In this
article, we show that for negative Atwood numbers, there exist special
sequences of shocks which result in a nearly perfectly suppressed instability
growth. We demonstrate this principle computationally and experimentally with
stepped fliers and phase transition materials. A fascinating immediate
corollary is that in specific instances a phase transitioning material may
self-suppress RMI
SCI
Persistent homology is a powerful tool in Topological Data Analysis (TDA) to capture the topological properties of data succinctly at different spatial resolutions. For graphical data, the shape, and structure of the neighborhood of individual data items (nodes) are an essential means of characterizing their properties. We propose the use of persistent homology methods to capture structural and topological properties of graphs and use it to address the problem of link prediction. We achieve encouraging results on nine different real-world datasets that attest to the potential of persistent homology-based methods for network analysis
Patient-centric trials for therapeutic development in precision oncology
An enhanced understanding of the molecular pathology of disease gained from genomic studies is facilitating the development of treatments that target discrete molecular subclasses of tumours. Considerable associated challenges include how to advance and implement targeted drug-development strategies. Precision medicine centres on delivering the most appropriate therapy to a patient on the basis of clinical and molecular features of their disease. The development of therapeutic agents that target molecular mechanisms is driving innovation in clinical-trial strategies. Although progress has been made, modifications to existing core paradigms in oncology drug development will be required to realize fully the promise of precision medicine
Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.
A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions
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