946 research outputs found
On the most compact regular lattice in large dimensions: A statistical mechanical approach
In this paper I will approach the computation of the maximum density of
regular lattices in large dimensions using a statistical mechanics approach.
The starting point will be some theorems of Roger, which are virtually unknown
in the community of physicists. Using his approach one can see that there are
many similarities (and differences) with the problem of computing the entropy
of a liquid of perfect spheres. The relation between the two problems is
investigated in details. Some conjectures are presented, that need further
investigation in order to check their consistency.Comment: 27 page
Profitable Farming Systems for the Intensive Spring Wheat Area in South Dakota
The plan of the Department of Farm Economics of South Dakota State College is to study in detail the organization and operation of farms in each of the principal type-of-farming areas in the State. The object of these studies is to determine the systems of farming likely to give good results in an area over a period of years, including enterprise combinations which appear advantageous; practices giving good results in the principal enterprises; and adjustments between and within the enterprises likely to be desirable with changing conditions
Bounding the norm of a log-concave vector via thin-shell estimates
Chaining techniques show that if X is an isotropic log-concave random vector
in R^n and Gamma is a standard Gaussian vector then E |X| < C n^{1/4} E |Gamma|
for any norm |*|, where C is a universal constant. Using a completely different
argument we establish a similar inequality relying on the thin-shell constant
sigma_n = sup ((var|X|^){1/2} ; X isotropic and log-concave on R^n).
In particular, we show that if the thin-shell conjecture sigma_n = O(1)
holds, then n^{1/4} can be replaced by log (n) in the inequality.
As a consequence, we obtain certain bounds for the mean-width, the dual
mean-width and the isotropic constant of an isotropic convex body.
In particular, we give an alternative proof of the fact that a positive
answer to the thin-shell conjecture implies a positive answer to the slicing
problem, up to a logarithmic factor.Comment: preliminary version, 13 page
Humanizing StudentâTeacher Relationships for Black Children: Implications for Teachersâ SocialâEmotional Training
A growing number of scholars in the field of urban education compellingly demonstrate the myriad ways U.S. schooling for Black youth is dehumanizing. Social and emotional learning (SEL), particularly, transformative social emotional learning (TSEL) has come to the fore as a promising intervention to promote positive inclusive school cultures and relationships while recognizing and accounting for the realities of racial oppression. Here, we discuss teachersâ capacity to develop and negotiate studentâteacher relationships that acknowledge and actively confront the dehumanization of Black youth in schools. We provide recommendations for teachersâ social emotional training that can effectively humanize learning environments for Black youth
Grids of Stellar Models and Frequencies with CLES + LOSC
We present a grid of stellar models, obtained with the CLES evolution code,
following the specification of ESTA-Task1, and the corresponfing seismic
properties, computed with the LOSC code. We provide a complete description of
the corresponding files that will be available on the ESTA web-pages.Comment: 8 pages, accepted for publication in Astrophys. Space Sci.
(CoRoT/ESTA Volume
Coloring translates and homothets of a convex body
We obtain improved upper bounds and new lower bounds on the chromatic number
as a linear function of the clique number, for the intersection graphs (and
their complements) of finite families of translates and homothets of a convex
body in \RR^n.Comment: 11 pages, 2 figure
Advance telephone calls ahead of reminder questionnaires increase response rate in non-responders compared to questionnaire reminders only : The RECORD phone trial
Peer reviewedPublisher PD
Can one see the fundamental frequency of a drum?
We establish two-sided estimates for the fundamental frequency (the lowest
eigenvalue) of the Laplacian in an open subset G of R^n with the Dirichlet
boundary condition. This is done in terms of the interior capacitary radius of
G which is defined as the maximal possible radius of a ball B which has a
negligible intersection with the complement of G. Here negligibility of a
subset F in B means that the Wiener capacity of F does not exceed gamma times
the capacity of B, where gamma is an arbitrarily fixed constant between 0 and
1. We provide explicit values of constants in the two-sided estimates.Comment: 18 pages, some misprints correcte
Cell wall degrading enzymes originating from rhizoctonia solani increase sugar beet root damage in the presence of leuconostoc mesenteroides
Sugar beet crown and root rot caused by Rhizoctonia solani is a major yield constraint. Root rot is highly increased when R. solani and Leuconostoc mesenteroides co-infect roots. We hypothesized that the absence of plant cell wall degrading enzymes in L. mesenteroides and their supply by R. solani during close contact, causes increased damage. In planta root inoculation with or without cell wall degrading enzymes showed greater rot when L. mesenteroides was combined with cellulase (49 mm rot), polygalacturonase (48 mm), and pectin lyase (35 mm) versus these enzymes (0â11 mm), R. solani (13 mm), and L. mesenteroides (22 mm) individually. Carbohydrate analysis revealed increase in simpler carbohydrates namely glucose + galactose, and fructose in the infected roots versus mock control, possibly due to the degradation of complex cell wall carbohydrates. Expression of R. solani cellulase, polygalacturonase, and pectin lyase genes during root infection corroborated well with the enzyme data. Global mRNAseq analysis identified candidate genes and highly co-expressed gene clusters (in all 3 organisms) that might be critical in host plant defense and pathogenesis. Future targeting of R. solani cell wall degrading enzymes could be an effective strategy to mitigate root damage during interaction with L. mesenteroides
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