1,028 research outputs found
Charged Cylindrical Collapse of Anisotropic Fluid
Following the scheme developed by Misner and Sharp, we discuss the dynamics
of gravitational collapse. For this purpose, an interior cylindrically
symmetric spacetime is matched to an exterior charged static cylindrically
symmetric spacetime using the Darmois matching conditions. Dynamical equations
are obtained with matter dissipating in the form of shear viscosity. The effect
of charge and dissipative quantities over the cylindrical collapse are studied.
Finally, we show that homogeneity in energy density and conformal flatness of
spacetime are necessary and sufficient for each other.Comment: 19 pages, accepted for publication in Gen. Relativ. Gra
Bondian frames to couple matter with radiation
A study is presented for the non linear evolution of a self gravitating
distribution of matter coupled to a massless scalar field. The characteristic
formulation for numerical relativity is used to follow the evolution by a
sequence of light cones open to the future. Bondian frames are used to endow
physical meaning to the matter variables and to the massless scalar field.
Asymptotic approaches to the origin and to infinity are achieved; at the
boundary surface interior and exterior solutions are matched guaranteeing the
Darmois--Lichnerowicz conditions. To show how the scheme works some numerical
models are discussed. We exemplify evolving scalar waves on the following fixed
backgrounds: A) an atmosphere between the boundary surface of an incompressible
mixtured fluid and infinity; B) a polytropic distribution matched to a
Schwarzschild exterior; C) a Schwarzschild- Schwarzschild spacetime. The
conservation of energy, the Newman--Penrose constant preservation and other
expected features are observed.Comment: 20 pages, 6 figures; to appear in General Relativity and Gravitatio
Purification and characterisation of the yeast plasma membrane ATP binding cassette transporter Pdr11p.
The ATP binding cassette (ABC) transporters Pdr11p and its paralog Aus1p are expressed under anaerobic growth conditions at the plasma membrane of the yeast Saccharomyces cerevisiae and are required for sterol uptake. However, the precise mechanism by which these ABC transporters facilitate sterol movement is unknown. In this study, an overexpression and purification procedure was developed with the aim to characterise the Pdr11p transporter. Engineering of Pdr11p variants fused at the C terminus with green fluorescent protein (Pdr11p-GFP) and containing a FLAG tag at the N terminus facilitated expression analysis and one-step purification, respectively. The detergent-solubilised and purified protein displayed a stable ATPase activity with a broad pH optimum near 7.4. Mutagenesis of the conserved lysine to methionine (K788M) in the Walker A motif abolished ATP hydrolysis. Remarkably, and in contrast to Aus1p, ATPase activity of Pdr11p was insensitive to orthovanadate and not specifically stimulated by phosphatidylserine upon reconstitution into liposomes. Our results highlight distinct differences between Pdr11p and Aus1p and create an experimental basis for further biochemical studies of both ABC transporters to elucidate their function
Studies on combining ability in tomato (Solanum lycopersicum L.)
ArticleThe present study was done seven elite tomato lines (Solamun lycopersicum L.) of determinate and indeterminate growth with good yield potential and good combining ability, using diallel fashion without reciprocals to produce 21 F1s. General combining ability (GCA) and Specific combining ability (SCA) analysis were conducted, with Diallel-SAS, assessing six yield and component traits. Results showed highly significant differences (p ≤ 0.01) among genotypes, as well as in GCA and SCA effects in all the characteristics that was assessed, with the exception of Days to First Cut. The results revealed that variance contribution to the yield attributed to the crossings had more non-additive effects (SCA) than additive effects (GCA). Furthermore, Line D4 had the greatest effect on yield in terms of GCA, as well in AFW (Average Fruit Weight), NFP (Number of Fruits per Plant) and PD (Polar Diameter) followed by D3 and K3. These lines can be used as donor parent in future tomato-breeding program. Hybrids K3×D4, R1×Y53, D3×IR13 and F3×Y53 had the highest level of SCA, with average yields of 93 t ha-1. These potential hybrids could be exploited at commercial level after critical testing
Critical Collapse of Cylindrically Symmetric Scalar Field in Four-Dimensional Einstein's Theory of Gravity
Four-dimensional cylindrically symmetric spacetimes with homothetic
self-similarity are studied in the context of Einstein's Theory of Gravity, and
a class of exact solutions to the Einstein-massless scalar field equations is
found. Their local and global properties are investigated and found that they
represent gravitational collapse of a massless scalar field. In some cases the
collapse forms black holes with cylindrical symmetry, while in the other cases
it does not. The linear perturbations of these solutions are also studied and
given in closed form. From the spectra of the unstable eigen-modes, it is found
that there exists one solution that has precisely one unstable mode, which may
represent a critical solution, sitting on a boundary that separates two
different basins of attraction in the phase space.Comment: Some typos are corrected. The final version to appear in Phys. Rev.
Genetic components for fodder yield and agronomic characters in maize lines
In maize hybrid development, it is essential to know the parent’s performance per se
in different environments as well as the genetic base in populations in order to facilitate selection
of superior lines. The objective of this work was to estimate the genetic variance and heritability
while assessing agronomic behavior in 237 maize fodder lines featuring different inbred levels
and origin in two different locations. Traits such as plant height, cob height, stem diameter, and
fodder yield were taken. A combined variance analysis was carried out using this information.
The variable mean squares showing significant differences were used to estimate the genetic
variance components. Significant differences were observed (p ≤ 0.01) for the line variation
source and location × line interaction in all assessed characteristics. The genetic parameter
estimation provided information on the existing genetic variance and heritability among the
population which is important for the progress of the selection process. Lines CLWN701,
CLWN345, CML476, CML216, CLWQ232, and CML 528 measured 74.8, 72.2, 67.7, 65.8, 63.8
and 62.5 t ha-1
, respectively showed the highest yield potential for green fodder
Range shifting species reduce phylogenetic diversity in high latitude communities via competition
Acknowledgements We thank Heather Bodie and Debbie Young for assistance in the field, and local landowners for permissions to study and sample damselflies on their land. Brad Duthie provided helpful comments on an earlier version of this manuscript. The project was supported by a NERC DTP fellowship to R.N.L.F. and a start-up grant to L.T.L. provided by the University of Aberdeen. Data accessibility All data used in this study have been deposited in Dryad Digital Repository: https://doi.org/10.5061/dryad.kp89j (Fitt & Lancaster 2017).Peer reviewedPostprin
New Upper Limit of Terrestrial Equivalence Principle Test for Rotating Extended Bodies
Improved terrestrial experiment to test the equivalence principle for
rotating extended bodies is presented, and a new upper limit for the violation
of the equivalence principle is obtained at the level of 1.6, which is limited by the friction of the rotating gyroscope. It
means the spin-gravity interaction between the extended bodies has not been
observed at this level.Comment: 4 page
Phenomenology of -CDM model: a possibility of accelerating Universe with positive pressure
Among various phenomenological models, a time-dependent model is selected here to investigate the -CDM cosmology.
Using this model the expressions for the time-dependent equation of state
parameter and other physical parameters are derived. It is shown that
in model accelerated expansion of the Universe takes place at negative
energy density, but with a positive pressure. It has also been possible to
obtain the change of sign of the deceleration parameter during cosmic
evolution.Comment: 16 Latex pages, 11 figures, Considerable modifications in the text;
Accepted in IJT
Maintenance Therapies for Hodgkin and Non-Hodgkin Lymphomas after Autologous Transplantation: A Consensus Project of ASBMT, CIBMTR, and the Lymphoma Working Party of EBMT
Importance: Maintenance therapies are often considered as a therapeutic strategy in patients with lymphoma following autologous hematopoietic cell transplantation (auto-HCT) to mitigate the risk of disease relapse. With an evolving therapeutic landscape, where novel drugs are moving earlier in therapy lines, evidence relevant to contemporary practice is increasingly limited. The American Society for Blood and Marrow Transplantation (ASBMT), Center for International Blood and Marrow Transplant Research (CIBMTR), and European Society for Blood and Marrow Transplantation (EBMT) jointly convened an expert panel with diverse expertise and geographical representation to formulate consensus recommendations regarding the use of maintenance and/or consolidation therapies after auto-HCT in patients with lymphoma. Observations: The RAND-modified Delphi method was used to generate consensus statements where at least 75% vote in favor of a recommendation was considered as consensus. The process included 3 online surveys moderated by an independent methodological expert to ensure anonymity and an in-person meeting. The panel recommended restricting the histologic categories covered in this project to Hodgkin lymphoma (HL), mantle cell lymphoma (MCL), diffuse large B-cell lymphoma (DLBCL), and follicular lymphoma. On completion of the voting process, the panel generated 22 consensus statements regarding post auto-HCT maintenance and/or consolidation therapies. The grade A recommendations included endorsement of: (1) brentuximab vedotin (BV) maintenance and/or consolidation in BV-na\uefve high-risk HL, (2) rituximab maintenance in MCL undergoing auto-HCT after first-line therapy, (3) rituximab maintenance in rituximab-na\uefve FL, and (4) No post auto-HCT maintenance was recommended in DLBCL. The panel also developed consensus statements for important real-world clinical scenarios, where randomized data are lacking to guide clinical practice. Conclusions and Relevance: In the absence of contemporary evidence-based data, the panel found RAND-modified Delphi methodology effective in providing a rigorous framework for developing consensus recommendations for post auto-HCT maintenance and/or consolidation therapies in lymphoma.
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