99 research outputs found
Reanalyzing the upper limit on the tensor-to-scalar perturbation ratio r_T in a quartic potential inflationary model
We study the polynomial chaotic inflation model with a single scalar field in
a double well quartic potential which has recently been shown to be consistent
with Planck data. In particular, we study the effects of lifting the degeneracy
between the two vacua on the inflationary observables, i.e. spectral index n_s
and tensor-to-scalar perturbation ratio r_T. We find that removing the
degeneracy allows the model to satisfy the upper limit constraints on r_T from
Planck data, provided the field starts near the local maximum. We also
calculate the scalar power spectrum and non-Gaussianity parameter f_NL for the
primordial scalar perturbations in this model.Comment: 7 pages, 7 figures; v2: discussion added, submitted to Phys. Lett. B;
v3: published versio
Functional recombinant antibodies against human chorionic gonadotropin expressed in plants
Single-chain variable fragments, diabodies and chimeric antibodies (mouse variable domains and human immunoglobulin constant domains) were engineered by DNA recombinant technique and expressed transiently in tobacco leaves. The plants expressed the three types of antigen-binding moieties, accurately and faithfully. The yield obtained was 32 mg, 40 mg and 20 mg respectively, per kg of wet weight of leaves. The chimeric antibody had high affinity for human chorionic gonadotropin (Ka=1.9Ă1010Mâ1). All three forms of the recombinant antibodies expressed by plants inhibited the binding of hCG to receptor on Leydig cells
A program for a problem free Cosmology within a framework of a rich class of scalar tensor theories
A search for a problem free cosmology within the framework of an effective
non - minimally coupled scalar tensor theory is suggested. With appropriate
choice of couplings in variants of a Lee - Wick model [as also in a model
supporting Q - ball solutions], non topological solutions [NTS's], varying in
size upto 10 kpc to 1 Mpc can exist. We explore the properties of a ``toy''
Milne model containing a distribution of NTS domains. The interior of these
domains would be regions where effective gravitational effects would be
indistinguishable from those expected in standard Einstein theory. For a large
class of non - minimal coupling terms and the scalar effective potential, the
effective cosmological constant identically vanishes. The model passes
classical cosmological tests and we describe reasons to expect it to fare well
as regards nucleosynthesis and structure formation.Comment: 20 pages, Plain Tex, references added and expanded the previous
version of article, 2 figures available from [email protected]
Hawking Radiation of a Quantum Black Hole in an Inflationary Universe
The quantum stress-energy tensor of a massless scalar field propagating in
the two-dimensional Vaidya-de Sitter metric, which describes a classical model
spacetime for a dynamical evaporating black hole in an inflationary universe,
is analyzed. We present a possible way to obtain the Hawking radiation terms
for the model with arbitrary functions of mass. It is used to see how the
expansion of universe will affect the dynamical process of black hole
evaporation. The results show that the cosmological inflation has an
inclination to depress the black hole evaporation. However, if the cosmological
constant is sufficiently large then the back-reaction effect has the
inclination to increase the black hole evaporation. We also present a simple
method to show that it will always produce a divergent flux of outgoing
radiation along the Cauchy horizon where the curvature is a finite value. This
means that the Hawking radiation will be very large in there and shall modify
the classical spacetime drastically. Therefore the black hole evaporation
cannot be discussed self-consistently on the classical Vaidya-type spacetime.
Our method can also be applied to analyze the quantum stress-energy tensor in
the more general Vaidya-type spacetimes.Comment: Proper boundary will lead to anti-evaporation of schwarzschild-de
Sitter black holes, as corrected in Class. Quantum Grav. 11 (1994) 28
Reproductive exocrine and endocrine profile of female langur monkeys, Presbytis entellus
In 5 caged langurs menstrual cycle length (for 125 cycles) varied from 18 to 45 days with a mean ± s.d. of 26·3 ± 3·6 days. Menstruation lasted for 2 days. A distinct cycle of vaginal smear cells was observed with a maximum cornification on Day 10 coinciding with the serum oestradiol peak. A monophasic pattern of vaginal temperature with a significant nadir on Day 11, 1 day after the oestradiol peak, was observed. Serum sialic acid concentrations directly reflected the oestrogenic activity and showed a significant peak on Day 10, coinciding with the oestradiol peak and was followed by a progesterone rise. Langurs menstruated throughout the year without showing any sign of summer amenorrhoea. We suggest that maximum cornification, vaginal temperature nadir and serum sialic acid peak could be used as markers for prediction and detection of the time of ovulation in langur monkeys
Comparative Study for Understanding the Spatial Growth Pattern of Pune and Jaipur City from 1990 to 2020
Understanding the urban form, conducting spatial change analysis of an urban area using time-series data, and identifying urban growth drivers play a crucial part in framing policies for sustainable planning practices. In this research, an inverse S-curve function is employed to examine Urban Land Densities (ULD) derived from concentric divisions of urban regions in Pune and Jaipur. The inverse S-curve quantitatively describes variations in Urban Land Density (ULD) from the urban center to the outskirts. Consequently, the parameters identified during the curve-fitting process offer information about the urban form of the cities, shedding light on their rate of expansion, level of compactness, and the nature of sprawl. Built-up area is determined from the Landsat datasets for the years 1991, 1996, 2001, 2006, 2011,2016, and 2021. The analysis confirmed that Pune revealed an increase in sprawling, expansive, and low-density development. As a city that has grown linearly, Jaipur has experienced more constrained growth than Pune. Additionally, the fitted ULD equation provided an accurately fitted radius for Jaipur, but not for Pune, highlighting the equation's shortcomings. The direction analysis and understanding of the change in the slopes of the S curve further led to identifying growth drivers, broadly classified into proximity, government intervention, socioeconomic, and physical factors. The study can help achieve future research objectives in simulating and modeling urban growth and creating policies to deal with related problems
Does the generalized second law require entropy bounds for a charged system?
We calculate the net change in generalized entropy occurring when one carries
out the gedanken experiment in which a box initially containing energy ,
entropy and charge is lowered adiabatically toward a
Reissner-Nordstr\"{o}m black hole and then dropped in. This is an extension of
the work of Unruh-Wald to a charged system (the contents of the box possesses a
charge ). Their previous analysis showed that the effects of acceleration
radiation prevent violation of the generalized second law of thermodynamics. In
our more generic case, we show that the properties of the thermal atmosphere
are equally important when charge is present. Indeed, we prove here that an
equilibrium condition for the the thermal atmosphere and the physical
properties of ordinary matter are sufficient to enforce the generalized second
law. Thus, no additional assumptions concerning entropy bounds on the contents
of the box need to be made in this process. The relation between our work and
the recent works of Bekenstein and Mayo, and Hod (entropy bound for a charged
system) are also discussed.Comment: 18pages, RevTex, no figure
Cosmic Censorship, Area Theorem, and Self-Energy of Particles
The (zeroth-order) energy of a particle in the background of a black hole is
given by Carter's integrals. However, exact calculations of a particle's {\it
self-energy} (first-order corrections) are still beyond our present reach in
many situations. In this paper we use Hawking's area theorem in order to derive
bounds on the self-energy of a particle in the vicinity of a black hole.
Furthermore, we show that self-energy corrections {\it must} be taken into
account in order to guarantee the validity of Penrose cosmic censorship
conjecture.Comment: 11 page
Behavior of Quasilocal Mass Under Conformal Transformations
We show that in a generic scalar-tensor theory of gravity, the ``referenced''
quasilocal mass of a spatially bounded region in a classical solution is
invariant under conformal transformations of the spacetime metric. We first
extend the Brown-York quasilocal formalism to such theories to obtain the
``unreferenced'' quasilocal mass and prove it to be conformally invariant. The
appropriate reference term in this case is defined by generalizing the
Hawking-Horowitz prescription, which was originally proposed for general
relativity. For such a choice of reference term, the referenced quasilocal mass
for a general spacetime solution is obtained. This expression is shown to be a
conformal invariant provided the conformal factor is a monotonic function of
the scalar field. We apply this expression to the case of static spherically
symmetric solutions with arbitrary asymptotics to obtain the referenced
quasilocal mass of such solutions. Finally, we demonstrate the conformal
invariance of our quasilocal mass formula by applying it to specific cases of
four-dimensional charged black hole spacetimes, of both the asymptotically flat
and non-flat kinds, in conformally related theories.Comment: LaTeX, 31 pages, one ps figur
Radiative falloff in Schwarzschild-de Sitter spacetime
We consider the time evolution of a scalar field propagating in
Schwarzschild-de Sitter spacetime. At early times, the field behaves as if it
were in pure Schwarzschild spacetime; the structure of spacetime far from the
black hole has no influence on the evolution. In this early epoch, the field's
initial outburst is followed by quasi-normal oscillations, and then by an
inverse power-law decay. At intermediate times, the power-law behavior gives
way to a faster, exponential decay. At late times, the field behaves as if it
were in pure de Sitter spacetime; the structure of spacetime near the black
hole no longer influences the evolution in a significant way. In this late
epoch, the field's behavior depends on the value of the curvature-coupling
constant xi. If xi is less than a critical value 3/16, the field decays
exponentially, with a decay constant that increases with increasing xi. If xi >
3/16, the field oscillates with a frequency that increases with increasing xi;
the amplitude of the field still decays exponentially, but the decay constant
is independent of xi.Comment: 10 pages, ReVTeX, 5 figures, references updated, and new section
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