661 research outputs found
The complexity of global cardinality constraints
In a constraint satisfaction problem (CSP) the goal is to find an assignment
of a given set of variables subject to specified constraints. A global
cardinality constraint is an additional requirement that prescribes how many
variables must be assigned a certain value. We study the complexity of the
problem CCSP(G), the constraint satisfaction problem with global cardinality
constraints that allows only relations from the set G. The main result of this
paper characterizes sets G that give rise to problems solvable in polynomial
time, and states that the remaining such problems are NP-complete
A TARGETED LOAD-CARRIAGE TRAINING PROGRAM ELICITS POSITIVE ADAPTATIONS AFTER 10-WEEKS
The purpose of this study was to identify and characterise physical performance responses to a targeted 10-week load-carriage physical training intervention in males. Performance measures of maximal strength, heart rate, rating of perceived exertion, and basic fitness from nine male civilians before and after the 10-week training intervention are presented. There were significant increases in maximal force (~200 N) and aerobic performance (Level. Shuttle 8.9 vs 9,4 variables). Small-to-large effect sizes were shown for basic fitness and perceptual responses. The 10-week load-carriage physical training intervention elicited physical performance improvements and may facilitate load-carriage task performance
A scaling-invariant algorithm for linear programming whose running time depends only on the constraint matrix
Following the breakthrough work of Tardos in the bit-complexity model,
Vavasis and Ye gave the first exact algorithm for linear programming in the
real model of computation with running time depending only on the constraint
matrix. For solving a linear program (LP) , Vavasis and Ye developed a primal-dual
interior point method using a 'layered least squares' (LLS) step, and showed
that iterations suffice to solve (LP)
exactly, where is a condition measure controlling the size of
solutions to linear systems related to .
Monteiro and Tsuchiya, noting that the central path is invariant under
rescalings of the columns of and , asked whether there exists an LP
algorithm depending instead on the measure , defined as the
minimum value achievable by a column rescaling of ,
and gave strong evidence that this should be the case. We resolve this open
question affirmatively.
Our first main contribution is an time algorithm which
works on the linear matroid of to compute a nearly optimal diagonal
rescaling satisfying . This
algorithm also allows us to approximate the value of up to a
factor . As our second main contribution, we develop a
scaling invariant LLS algorithm, together with a refined potential function
based analysis for LLS algorithms in general. With this analysis, we derive an
improved iteration bound for
optimally solving (LP) using our algorithm. The same argument also yields a
factor improvement on the iteration complexity bound of the original
Vavasis-Ye algorithm
Wrapped branes with fluxes in 8d gauged supergravity
We study the gravity dual of several wrapped D-brane configurations in
presence of 4-form RR fluxes partially piercing the unwrapped directions. We
present a systematic approach to obtain these solutions from those without
fluxes. We use D=8 gauged supergravity as a starting point to build up these
solutions. The configurations include (smeared) M2-branes at the tip of a G_2
cone on S^3 x S^3, D2-D6 branes with the latter wrapping a special Lagrangian
3-cycle of the complex deformed conifold and an holomorphic sphere in its
cotangent bundle T^*S^2, D3-branes at the tip of the generalized resolved
conifold, and others obtained by means of T duality and KK reduction. We
elaborate on the corresponding N=1 and N=2 field theories in 2+1 dimensions.Comment: 32 pages, LateX, v2: minor changes, reference added, v3: section
3.5.2 improve
Casimir energy in multiply connected static hyperbolic Universes
We generalize a previously obtained result, for the case of a few other
static hyperbolic universes with manifolds of nontrivial topology as spatial
sections.Comment: accepted for publicatio
Length of the weaning period affects postweaning growth, health, and carcass merit of ranch-direct beef calves weaned during the fall
Bovine respiratory disease (BRD) is the most economically devastating feedlot disease. Risk factors associated with incidence of BRD include (1) stress associated with maternal separation, (2) stress associated with introduction to an unfamiliar environment, (3) poor intake associated with introduction of novel feedstuffs into the animal\u27s diet, (4) exposure to novel pathogens upon transport to a feeding facility and commingling with unfamiliar cattle, (5) inappropriately administered respiratory disease vaccination programs, and (6) poor response to respiratory disease vaccination programs. Management practices that are collectively referred to as preconditioning are thought to minimize damage to the beef carcass from the BRD complex. Preconditioning management reduces the aforementioned risk factors for respiratory disease by (1) using a relatively long ranch-of-origin weaning period following maternal separation, (2) exposing calves to concentrate-type feedstuffs, and (3) producing heightened resistance to respiratory disease-causing organisms through a preweaning vaccination program. The effectiveness of such programs for preserving animal performance is highly touted by certain segments of the beef industry. Ranch-of-origin weaning periods of up to 60 days are suggested for preconditioning beef calves prior to sale; however, optimal length of the ranch-of-origin weaning period has not been determined experimentally. The objective of this study was to test the validity of beef industry assumptions about appropriate length of ranch-of-origin weaning periods for calves aged 160 to 220 days and weaned during the fall
Current-Current Deformations of Conformal Field Theories, and WZW Models
Moduli spaces of conformal field theories corresponding to current-current
deformations are discussed. For WZW models, CFT and sigma model considerations
are compared. It is shown that current-current deformed WZW models have
WZW-like sigma model descriptions with non-bi-invariant metrics, additional
B-fields and a non-trivial dilaton.Comment: 30 pages, latex, v2: remarks and references adde
No Evidence for Disease History as a Risk Factor for Narcolepsy after A(H1N1)pdm09 Vaccination
OBJECTIVES: To investigate disease history before A(H1N1)pdm09 vaccination as a risk factor for narcolepsy.METHODS: Case-control study in Sweden. Cases included persons referred for a Multiple Sleep Latency Test between 2009 and 2010, identified through diagnostic sleep centres and confirmed through independent review of medical charts. Controls, selected from the total population register, were matched to cases on age, gender, MSLT-referral date and county of residence. Disease history (prescriptions and diagnoses) and vaccination history was collected through telephone interviews and population-based healthcare registers. Conditional logistic regression was used to investigate disease history before A(H1N1)pdm09 vaccination as a risk-factor for narcolepsy.RESULTS: In total, 72 narcolepsy cases and 251 controls were included (range 3-69 years mean19-years). Risk of narcolepsy was increased in individuals with a disease history of nervous system disorders (OR range = 3.6-8.8) and mental and behavioural disorders (OR = 3.8, 95% CI 1.6-8.8) before referral. In a second analysis of vaccinated individuals only, nearly all initial associations were no longer statistically significant and effect sizes were smaller (OR range = 1.3-2.6). A significant effect for antibiotics (OR = 0.4, 95% CI 0.2-0.8) and a marginally significant effect for nervous system disorders was observed. In a third case-only analysis, comparing cases referred before vaccination to those referred after; prescriptions for nervous system disorders (OR = 26.0 95% CI 4.0-170.2) and ADHD (OR = 35.3 95% CI 3.4-369.9) were statistically significant during the vaccination period, suggesting initial associations were due to confounding by indication.CONCLUSION: The findings of this study do not support disease history before A(H1N1)pdm09 vaccination as a risk factor for narcolepsy
Nucleon Axial Form Factor from Lattice QCD
Results for the isovector axial form factors of the proton from a lattice QCD
calculation are presented for both point-split and local currents. They are
obtained on a quenched lattice at with Wilson
fermions for a range of quark masses from strange to charm. We determine the
finite lattice renormalization for both the local and point-split currents of
heavy quarks. Results extrapolated to the chiral limit show that the
dependence of the axial form factor agrees reasonably well with experiment. The
axial coupling constant calculated for the local and the point-split
currents is about 6\% and 12\% smaller than the experimental value
respectively.Comment: 8 pages, 5 figures (included in part 2), UK/93-0
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