2,003 research outputs found
Accurate and efficient gravitational waveforms for certain galactic compact binaries
Stellar-mass compact binaries in eccentric orbits are almost guaranteed
sources of gravitational waves for Laser Interferometer Space Antenna. We
present a prescription to compute accurate and efficient gravitational-wave
polarizations associated with bound compact binaries of arbitrary eccentricity
and mass ratio moving in slowly precessing orbits. We compare our approach with
those existing in the literature and present its advantages.Comment: 10 pages, 7 figures, to be published in MNRA
Refined Topological Vertex and Instanton Counting
It has been proposed recently that topological A-model string amplitudes for
toric Calabi-Yau 3-folds in non self-dual graviphoton background can be
caluculated by a diagrammatic method that is called the ``refined topological
vertex''. We compute the extended A-model amplitudes for SU(N)-geometries using
the proposed vertex. If the refined topological vertex is valid, these
computations should give rise to the Nekrasov's partition functions of N=2
SU(N) gauge theories via the geometric engineering. In this article, we verify
the proposal by confirming the equivalence between the refined A-model
amplitude and the K-theoretic version of the Nekrasov's partition function by
explicit computation.Comment: 22 pages, 6 figures, minor correction
Solutions to Cosmological Problems with Energy Conservation and Varying c, G and Lambda
The flatness and cosmological constant problems are solved with varying speed
of light c, gravitational coupling strength G and cosmological parameter
Lambda, by explicitly assuming energy conservation of observed matter. The
present solution to the flatness problem is the same as the previous solution
in which energy conservation was absent.Comment: 5 pages, Replaced with LaTex file with minor change
D-branes as a Bubbling Calabi-Yau
We prove that the open topological string partition function on a D-brane
configuration in a Calabi-Yau manifold X takes the form of a closed topological
string partition function on a different Calabi-Yau manifold X_b. This
identification shows that the physics of D-branes in an arbitrary background X
of topological string theory can be described either by open+closed string
theory in X or by closed string theory in X_b. The physical interpretation of
the ''bubbling'' Calabi-Yau X_b is as the space obtained by letting the
D-branes in X undergo a geometric transition. This implies, in particular, that
the partition function of closed topological string theory on certain bubbling
Calabi-Yau manifolds are invariants of knots in the three-sphere.Comment: 32 pages; v.2 reference adde
Label-Free Metabolic Classification of Single Cells in Droplets Using the Phasor Approach to Fluorescence Lifetime Imaging Microscopy.
Characterization of single cell metabolism is imperative for understanding subcellular functional and biochemical changes associated with healthy tissue development and the progression of numerous diseases. However, single-cell analysis often requires the use of fluorescent tags and cell lysis followed by genomic profiling to identify the cellular heterogeneity. Identifying individual cells in a noninvasive and label-free manner is crucial for the detection of energy metabolism which will discriminate cell types and most importantly critical for maintaining cell viability for further analysis. Here, we have developed a robust assay using the droplet microfluidic technology together with the phasor approach to fluorescence lifetime imaging microscopy to study cell heterogeneity within and among the leukemia cell lines (K-562 and Jurkat). We have extended these techniques to characterize metabolic differences between proliferating and quiescent cells-a critical step toward label-free single cancer cell dormancy research. The result suggests a droplet-based noninvasive and label-free method to distinguish individual cells based on their metabolic states, which could be used as an upstream phenotypic platform to correlate with genomic statistics. © 2018 International Society for Advancement of Cytometry
Relating prepotentials and quantum vacua of N=1 gauge theories with different tree-level superpotentials
We consider N=1 supersymmetric U(N) gauge theories with Z_k symmetric
tree-level superpotentials W for an adjoint chiral multiplet. We show that (for
integer 2N/k) this Z_k symmetry survives in the quantum effective theory as a
corresponding symmetry of the effective superpotential W_eff(S_i) under
permutations of the S_i. For W(x)=^W(h(x)) with h(x)=x^k, this allows us to
express the prepotential F_0 and effective superpotential W_eff on certain
submanifolds of the moduli space in terms of an ^F_0 and ^W_eff of a different
theory with tree-level superpotential ^W. In particular, if the Z_k symmetric
polynomial W(x) is of degree 2k, then ^W is gaussian and we obtain very
explicit formulae for F_0 and W_eff. Moreover, in this case, every vacuum of
the effective Veneziano-Yankielowicz superpotential ^W_eff is shown to give
rise to a vacuum of W_eff. Somewhat surprisingly, at the level of the
prepotential F_0(S_i) the permutation symmetry only holds for k=2, while it is
anomalous for k>2 due to subtleties related to the non-compact period
integrals. Some of these results are also extended to general polynomial
relations h(x) between the tree-level superpotentials.Comment: 27 pages, 10 figures, modified version to appear in JHEP, discussion
of the physical meaning of the Z_k symmetry adde
Second post-Newtonian gravitational radiation reaction for two-body systems: Nonspinning bodies
Starting from the recently obtained 2PN accurate forms of the energy and
angular momentum fluxes from inspiralling compact binaries, we deduce the
gravitational radiation reaction to 2PN order beyond the quadrupole
approximation - 4.5PN terms in the equation of motion - using the refined
balance method proposed by Iyer and Will. We explore critically the features of
their construction and illustrate them by contrast to other possible variants.
The equations of motion are valid for general binary orbits and for a class of
coordinate gauges. The limiting cases of circular orbits and radial infall are
also discussed.Comment: 38 pages, REVTeX, no figures, to appear in Phys. Rev.
Non-linear sigma-models in noncommutative geometry: fields with values in finite spaces
We study sigma-models on noncommutative spaces, notably on noncommutative
tori. We construct instanton solutions carrying a nontrivial topological charge
q and satisfying a Belavin-Polyakov bound. The moduli space of these instantons
is conjectured to consists of an ordinary torus endowed with a complex
structure times a projective space .Comment: Latex, 10 page
Broodstock development, breeding and larval rearing of cobia and pompano
Cobia (Rachycentron canadum) and silver pompano
(Trachinotus blochii) are two marine finfish species with very high
potential for aquaculture in India. Fast growth rate, adaptability
for captive breeding, low cost of production, good meat quality
and high market demand especially for sashimi industry are some
of the attributes that make cobia an excellent species for
aquaculture. In recent years the seed production and farming of
cobia is rapidly gaining momentum in many Asian countries.
Similarly, pompano is having fast growth rate, good meat quality
and high market demand. Envisaging the prospects of cobia and
pompano farming in India, broodstock development was initiated
at the Mandapam Regional Centre of Central Marine Fisheries
Research Institute in sea cages during 2008 and the first successful
induced breeding and seed production was achieved for cobia in
March – April 2010 and for pompano during July 2011
Pad\'e approximants for truncated post-Newtonian neutron star models
Pad\'e approximants to truncated post-Newtonian neutron star models are
constructed. The Pad\'e models converge faster to the general relativistic (GR)
solution than the truncated post-Newtonian ones. The evolution of initial data
using the Pad\'e models approximates better the evolution of full GR initial
data than the truncated Taylor models. In the absence of full GR initial data
(e.g., for neutron star binaries or black hole binary systems), Pad\'e initial
data could be a better option than the straightforward truncated post-Newtonian
(Taylor) initial data.Comment: 19 pages (RevTeX), 9 eps figures. Three new figures and additional
discussion on 1-parameter Pad\'e expansion. Accepted for publication in
Physical Review
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