2,247 research outputs found
Homogenization of Variational Inequalities for the p-Laplace Operator in Perforated Media Along Manifolds
We address homogenization problems of variational inequalities for the p-Laplace operator in a domain of Rn (n ? 3, p ? [2, n)) periodically perforated by balls of radius O(??) where ? > 1 and ? is the size of the period. The perforations are distributed along a (n ? 1)-dimensional manifold ? , and we impose constraints for solutions and their fluxes (associated with the p-Laplacian) on the boundary of the perforations. These constraints imply that the solution is positive and that the flux is bounded from above by a negative, nonlinear monotonic function of the solution multiplied by a parameter ? ?? , ? ? R and ? is a small parameter that we shall make to go to zero. We analyze different relations between the parameters p, n, ?, ? and ?, and obtain homogenized problems which are completely new in the literature even for the case p = 2.This work has been partially supported by the Spanish grant MINECO:MTM2013-44883-P
Hopping Conduction in Uniaxially Stressed Si:B near the Insulator-Metal Transition
Using uniaxial stress to tune the critical density near that of the sample,
we have studied in detail the low-temperature conductivity of p-type Si:B in
the insulating phase very near the metal-insulator transition. For all values
of temperature and stress, the conductivity collapses onto a single universal
scaling curve. For large values of the argument, the scaling function is well
fit by the exponentially activated form associated with variable range hopping
when electron-electron interactions cause a soft Coulomb gap in the density of
states at the Fermi energy. The temperature dependence of the prefactor,
corresponding to the T-dependence of the critical curve, has been determined
reliably for this system, and is proportional to the square-root of T. We show
explicitly that nevlecting the prefactor leads to substantial errors in the
determination of the scaling parameters and the critical exponents derived from
them. The conductivity is not consistent with Mott variable-range hopping in
the critical region nor does it obey this form for any range of the parameters.
Instead, for smaller argument of the scaling function, the conductivity of Si:B
is well fit by an exponential form with exponent 0.31 related to the critical
exponents of the system at the metal- insulator transition.Comment: 13 pages, 6 figure
Views of treatment decision making from adolescents with chronic illnesses and their parents: a pilot study
Objective Shared decision making may increase satisfaction with health care and improve outcomes, but little is known about adolescentsâ decisionâmaking preferences. The primary purpose of this study is to describe the decisionâmaking preferences of adolescents with chronic illnesses and their parents, and the extent to which they agree
Electrical properties of isotopically enriched neutron-transmutation-doped ^{70} Ge:Ga near the metal-insulator transition
We report the low temperature carrier transport properties of a series of
nominally uncompensated neutron-transmutation doped (NTD) ^{70} Ge:Ga samples
very close to the critical concentration N_c for the metal-insulator
transition. The concentration of the sample closest to N_c is 1.0004N_c and it
is unambiguously shown that the critical conductivity exponent is 0.5.
Properties of insulating samples are discussed in the context of Efros and
Shklovskii's variable range hopping conduction.Comment: 8 pages using REVTeX, 8 figures, published versio
Relativistic MHD with Adaptive Mesh Refinement
This paper presents a new computer code to solve the general relativistic
magnetohydrodynamics (GRMHD) equations using distributed parallel adaptive mesh
refinement (AMR). The fluid equations are solved using a finite difference
Convex ENO method (CENO) in 3+1 dimensions, and the AMR is Berger-Oliger.
Hyperbolic divergence cleaning is used to control the
constraint. We present results from three flat space tests, and examine the
accretion of a fluid onto a Schwarzschild black hole, reproducing the Michel
solution. The AMR simulations substantially improve performance while
reproducing the resolution equivalent unigrid simulation results. Finally, we
discuss strong scaling results for parallel unigrid and AMR runs.Comment: 24 pages, 14 figures, 3 table
Effect of Thiamine Status on Probability of Lake Ontario Chinook Salmon Spawning in the Upper or Lower Sections of Salmon River, New York
Consumption of thiaminaseâcontaining forage fishes reduces egg and muscle thiamine content and impairs the spawning migration of Cayuga Lake (New York) rainbow trout Oncorhynchus mykiss. Because some Chinook salmon O. tshawytscha from Lake Ontario have been shown to produce eggs low in thiamine, we examined the relationship between the migration of Chinook salmon and the thiamine content of their eggs spawned in the lower and upper sections of the Salmon River, a major tributary to Lake Ontario, in 2003â2006. Eggs from the upper section of the river were collected from 79 salmon returning to the state hatchery 25 river kilometers from the mouth. Eggs from 25 salmon in the lower section were collected from redds or females angled on redds approximately 1â3 km from the mouth. For all years combined, we found the mean thiamine concentration in eggs spawned in the lower section to be significantly lower than that for eggs spawned in the upper section; however, the annual differences in thiamine content of eggs between the upper and lower sections were significant only in 2003 and 2006. Binary logistic regression showed that the odds of spawning in the upper section was increased by 96% (95% confidence interval, 21â217%) for every nanomole of increase in the thiamine content of eggs. Therefore, the migratory achievement of Chinook salmon was significantly dependent on their thiamine status.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142217/1/nafm0895.pd
Non-structural protein 1 of avian influenza A viruses differentially inhibit NF-ÎșB promoter activation
<p>Abstract</p> <p>Background</p> <p>Influenza virus infection activates NF-ÎșB and is a general prerequisite for a productive influenza virus infection. On the other hand, non-structural protein 1 (NS1) suppresses this viral activated NF-ÎșB, presumably to prevent expression of NF-ÎșB mediated anti-viral response. NS1 proteins of influenza A viruses are divided into two groups, known as allele A and allele B. The possible functional relevance of this NS1 division to viral pathogenicity is lacking.</p> <p>Findings</p> <p>The ability of NS1 protein from two avian influenza subtypes, H6N8 and H4N6, to inhibit NF-ÎșB promoter activation was assessed. Further, efforts were made to characterize the genetic basis of this inhibition. We found that allele A NS1 proteins of H6N8 and H4N6 are significantly better in preventing dsRNA induced NF-ÎșB promoter activation compared to allele B of corresponding subtypes, in a species independent manner. Furthermore, the ability to suppress NF-ÎșB promoter activation was mapped to the effector domain while the RNA binding domain alone was unable to suppress this activation. Chimeric NS1 proteins containing either RNA binding domain of allele A and effector domain of allele B or vice versa, were equally potent in preventing NF-ÎșB promoter activation compared to their wt. NS1 protein of allele A and B from both subtypes expressed efficiently as detected by Western blotting and predominantly localized in the nucleus in both A549 and MiLu cells as shown by <it>in situ </it>PLA.</p> <p>Conclusions</p> <p>Here, we present another aspect of NS1 protein in inhibiting dsRNA induced NF-ÎșB activation in an allele dependent manner. This suggests a possible correlation with the virus's pathogenic potential.</p
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