15,429 research outputs found
Liouville soliton surfaces obtained using Darboux transformations
We construct parametric Liouville surfaces corresponding to parametric soliton solutions of the Liouville equation and Darboux-transformed counterparts. We also use a modified variation of parameters method together with the elliptic functions method to obtain the traveling wave solutions to Liouville equation and express the centroaffine invariant in terms of the soliton Hamiltonian
Type IIA Orientifold Limit of M-Theory on Compact Joyce 8-Manifold of Spin(7)-Holonomy
We show that M-theory compactified on a compact Joyce 8-manifold of
-holonomy, which yields an effective theory in with = 1
supersymmetry, admits at some special points in it moduli space a description
in terms of type IIA theory on an orientifold of compact Joyce 7-manifold of
-holonomy. We find the evidence in favour of this duality by computing the
massless spectra on both M-thory side and type IIA side. For the latter, we
compute the massless spectra by going to the orbifold limit of the Joyce
7-manifold.Comment: 26 pages, 2 eps figures, Latex file, two references and one footnote
added, corrected some typo
A COMPARATIVE PHARMACOGNOSTICAL EVALUATION OF THREE BOTANICAL SOURCE PLANTS OF JIVANTI
Objective: This study was undertaken to carry out a comparative pharmacognostical evaluation of three botanical source plants used in the name of classical Ayurvedic drug Jivanti.Methods: Leaves of three source plants of jivanti belonging to Asclepiadaceae family i.e. Leptadenia reticulata (Retz.), Holostemma ada-kodien Schult. and Wattakaka volubilis (Linn. f.) Stapf were evaluated for morphological and microscopical characters including quantitative microscopy, surface study, powder microscopy and histochemical studies.Results: Morphologically all the three species showed some similar characters like simple, opposite leaves with reticulate venation. The shape of the leaves were ovate to oblong in L reticulata and H ada-kodien whereas W volubilis was having broadly ovate or suborbicular leaves. Multicellular glandular warty trichomes, rosette crystals of calcium oxalate, lactiferous cells were observed in all the three species whereas prismatic crystals were also present in W volubilis. Palisade ratio and stomatal index were higher in H ada-kodien followed by L reticulata. Characteristic differences in the organoleptic characters like colour, taste, touch were observed in individual powder samples. Test for lignin, calcium oxalate crystal, starch grain and tannin showed a positive result in all the three samples.Conclusion: The present study reports specific pharmacognostical characteristics for the identification and differentiation of each botanical source plant. The observed results can also serve as a reference for any further investigations
Implications of a matter-radius measurement for the structure of Carbon-22
We study Borromean 2n-halo nuclei using effective field theory. We compute
the universal scaling function that relates the mean-square matter radius of
the 2n halo to dimensionless ratios of two- and three-body energies. We use the
experimental value of the rms matter radius of 22C measured by Tanaka et al. to
put constraints on its 2n separation energy and the 20C-n virtual energy. We
also explore the consequences of these constraints for the existence of excited
Efimov states in this nucleus. We find that, for 22C to have an rms matter
radius within 1-sigma of the experimental value, the two-neutron separation
energy of 22C needs to be below 100 keV. Consequently, this three-body halo
system can have an excited Efimov state only if the 20C-n system has a
resonance within 1 keV of the scattering threshold.Comment: 6 pages, 4 figure
Let's Twist Again: General Metrics of G(2) Holonomy from Gauged Supergravity
We construct all complete metrics of cohomogeneity one G(2) holonomy with S^3
x S^3 principal orbits from gauged supergravity. Our approach rests on a
generalization of the twisting procedure used in this framework. It corresponds
to a non-trivial embedding of the special Lagrangian three-cycle wrapped by the
D6-branes in the lower dimensional supergravity. There are constraints that
neatly reduce the general ansatz to a six functions one. Within this approach,
the Hitchin system and the flop transformation are nicely realized in eight
dimensional gauged supergravity.Comment: 31 pages, latex; v2: minor changes, references adde
Testing Conditional Independence of Discrete Distributions
We study the problem of testing \emph{conditional independence} for discrete
distributions. Specifically, given samples from a discrete random variable on domain , we want to distinguish,
with probability at least , between the case that and are
conditionally independent given from the case that is
-far, in -distance, from every distribution that has this
property. Conditional independence is a concept of central importance in
probability and statistics with a range of applications in various scientific
domains. As such, the statistical task of testing conditional independence has
been extensively studied in various forms within the statistics and
econometrics communities for nearly a century. Perhaps surprisingly, this
problem has not been previously considered in the framework of distribution
property testing and in particular no tester with sublinear sample complexity
is known, even for the important special case that the domains of and
are binary.
The main algorithmic result of this work is the first conditional
independence tester with {\em sublinear} sample complexity for discrete
distributions over . To complement our upper
bounds, we prove information-theoretic lower bounds establishing that the
sample complexity of our algorithm is optimal, up to constant factors, for a
number of settings. Specifically, for the prototypical setting when , we show that the sample complexity of testing conditional
independence (upper bound and matching lower bound) is
\[
\Theta\left({\max\left(n^{1/2}/\epsilon^2,\min\left(n^{7/8}/\epsilon,n^{6/7}/\epsilon^{8/7}\right)\right)}\right)\,.
\
Kahler Independence of the G2-MSSM
The G2-MSSM is a model of particle physics coupled to moduli fields with
interesting phenomenology both for colliders and astrophysical experiments. In
this paper we consider a more general model - whose moduli Kahler potential is
a completely arbitrary G2-holonomy Kahler potential and whose matter Kahler
potential is also more general. We prove that the vacuum structure and spectrum
of BSM particles is largely unchanged in this much more general class of
theories. In particular, gaugino masses are still supressed relative to the
gravitino mass and moduli masses. We also consider the effects of higher order
corrections to the matter Kahler potential and find a connection between the
nature of the LSP and flavor effects.Comment: Final version, matches the version published in JHE
Measuring gender norms about relationships in early adolescence : results from the global early adolescent study
Introduction: Gender norms are increasingly recognized as drivers of health and wellbeing. While early adolescence constitutes a critical window of development, there is limited understanding about how adolescents perceive gender relations across different cultural settings. This study used a mixed-method approach, grounded in the voices of young people around the world, to construct and test a cross-cultural scale assessing the perceptions of gender norms regulating romantic relationships between boys and girls in early adolescence.
Methods: The study draws on the Global Early Adolescent study (GEAS), a study focusing on gender norms and health related outcomes over the course of adolescence in urban poor settings worldwide. In-depth interviews were first conducted among approximately 200 adolescents between 10-14 years in seven sites across 4 continents to identify common scripts guiding romantic relations in early adolescence. These scripts were then transformed into a multidimensional scale. The scale was tested among 120 adolescents in each of 14 GEAS sites, followed by a second pilot among 75 adolescents in six sites. We evaluated the psychometric criteria of each subscale using principal component analysis, and parallel analysis, followed by exploratory factor analysis to guide the selection of a more parsimonious set of items.
Results: Results suggested a two-factor structure, consisting of an "adolescent romantic expectations" subscale and a "Sexual Double Standard" subscale. Both subscales yielded high internal validity in each site, with polychoric Cronbach alpha values above 0.70 with the exception of Kinshasa for the adolescent romantic expectations scale (0.64) and Hanoi for the sexual double standard scale (0.61).
Conclusion: This study reveals common perceptions of gendered norms about romantic engagement in early adolescence, normative for both sexes, but socially valued for boys while devaluated for girls. The findings illustrate that social hierarchies of power in romantic relationships form early in adolescence, regardless of cultural setting
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