11,678,271 research outputs found
On Super-Planckian thermal emission in far field regime
We study, in the framework of the Landauer theory, the thermal emission in
far-field regime, of arbitrary indefinite planar media and finite size systems.
We prove that the flux radiated by the former is bounded by the blackbody
emission while, for the second, there is in principle, no upper limit
demonstrating so the possibility for a super-Planckian thermal emission with
finite size systems
Contactless heat flux control with photonic devices
The ability to control electric currents in solids using diodes and
transistors is undoubtedly at the origin of the main developments in modern
electronics which have revolutionized the daily life in the second half of 20th
century. Surprisingly, until the year 2000 no thermal counterpart for such a
control had been proposed. Since then, based on pioneering works on the control
of phononic heat currents new devices were proposed which allow for the control
of heat fluxes carried by photons rather than phonons or electrons. The goal of
the present paper is to summarize the main advances achieved recently in the
field of thermal energy control with photons.Comment: Invited Revie
A mesoscopic description of radiative heat transfer at the nanoscale
We present a formulation of the nanoscale radiative heat transfer (RHT) using
concepts of mesoscopic physics. We introduce the analog of the Sharvin
conductance using the quantum of thermal conductance. The formalism provides a
convenient framework to analyse the physics of RHT at the nanoscale. Finally,
we propose a RHT experiment in the regime of quantized conductance
Ten years of the horse reference genome: insights into equine biology, domestication and population dynamics in the post-genome era.
The horse reference genome from the Thoroughbred mare Twilight has been available for a decade and, together with advances in genomics technologies, has led to unparalleled developments in equine genomics. At the core of this progress is the continuing improvement of the quality, contiguity and completeness of the reference genome, and its functional annotation. Recent achievements include the release of the next version of the reference genome (EquCab3.0) and generation of a reference sequence for the Y chromosome. Horse satellite-free centromeres provide unique models for mammalian centromere research. Despite extremely low genetic diversity of the Y chromosome, it has been possible to trace patrilines of breeds and pedigrees and show that Y variation was lost in the past approximately 2300 years owing to selective breeding. The high-quality reference genome has led to the development of three different SNP arrays and WGSs of almost 2000 modern individual horses. The collection of WGS of hundreds of ancient horses is unique and not available for any other domestic species. These tools and resources have led to global population studies dissecting the natural history of the species and genetic makeup and ancestry of modern breeds. Most importantly, the available tools and resources, together with the discovery of functional elements, are dissecting molecular causes of a growing number of Mendelian and complex traits. The improved understanding of molecular underpinnings of various traits continues to benefit the health and performance of the horse whereas also serving as a model for complex disease across species
Villase kanga soojusjuhtivuse sõltuvus sidusest ja järeltöötlusviisidest
http://tartu.ester.ee/record=b2654307~S1*es
Who's behind that mask and cape? The Asian leopard cat's Agouti (ASIP) allele likely affects coat colour phenotype in the Bengal cat breed.
Coat colours and patterns are highly variable in cats and are determined mainly by several genes with Mendelian inheritance. A 2-bp deletion in agouti signalling protein (ASIP) is associated with melanism in domestic cats. Bengal cats are hybrids between domestic cats and Asian leopard cats (Prionailurus bengalensis), and the charcoal coat colouration/pattern in Bengals presents as a possible incomplete melanism. The complete coding region of ASIP was directly sequenced in Asian leopard, domestic and Bengal cats. Twenty-seven variants were identified between domestic and leopard cats and were investigated in Bengals and Savannahs, a hybrid with servals (Leptailurus serval). The leopard cat ASIP haplotype was distinguished from domestic cat by four synonymous and four non-synonymous exonic SNPs, as well as 19 intronic variants, including a 42-bp deletion in intron 4. Fifty-six of 64 reported charcoal cats were compound heterozygotes at ASIP, with leopard cat agouti (A(P) (be) ) and domestic cat non-agouti (a) haplotypes. Twenty-four Bengals had an additional unique haplotype (A2) for exon 2 that was not identified in leopard cats, servals or jungle cats (Felis chaus). The compound heterozygote state suggests the leopard cat allele, in combination with the recessive non-agouti allele, influences Bengal markings, producing a darker, yet not completely melanistic coat. This is the first validation of a leopard cat allele segregating in the Bengal breed and likely affecting their overall pelage phenotype. Genetic testing services need to be aware of the possible segregation of wild felid alleles in all assays performed on hybrid cats
Age-dependent dynamic electrophysiological field potential behavior of atrioventricular node during experimental AF in rabbit
Introduction: Electrophysiological studies have demonstrated a relationship between aging and atrioventricular (AV) nodal conduction and refractoriness. The aim of the present study was to determine the effects of nodal aging on dynamic AV nodal field potential recording during atrial fibrillation (AF) in rabbit. Methods: Two groups of male New Zealand rabbits (neonatal 2-week-olds and adult 12-week-olds, n=14 each group) were used in this study. Field potential recordings were executed by silver electrodes with a diameter of 100 μM. Pre-defined stimulation protocols of AF, zone of concealment (ZOC) and concealed conduction for determination of the electrophysiological properties of the AV-node were separately applied in each group. Results: Results of the study showed that mean ventricular rate (HH) during atrial fibrillation was smaller in the neonatal compared to the adult group (229.1 ± 8.3 versus 198.6 ± 13.1 msec, respectively). Also ventricular distribution conduction pattern showed two peaks in the adult and one peak in the neonatal group. Analyzing the zone of concealment in different rates and after concealed beat indicated that the zone of concealment in neonates were significantly smaller compared with adult rabbits and increasing zone of concealment, which is accompanied with increasing ventricular rate is abrogated in the neonatal group (5 ± 3.3, 12.2 ± 6.3 msec). Conclusion: The results of this study showed that the electrophysiological protective dynamic behavior of the AV node during atrial fibrillation is smaller in neonates compared to adults. Narrower zone of concealment, abrogation rate dependent trend of the zone of concealment and shorter nodal refractoriness can account for the specific nodal electrophysiological properties of neonatal rabbits
Dynamics of heat transfer between nano systems
We develop a dynamical theory of heat transfer between two nano systems. In
particular, we consider the resonant heat transfer between two nanoparticles
due to the coupling of localized surface modes having a finite spectral width.
We model the coupled nanosystem by two coupled quantum mechanical oscillators,
each interacting with its own heat bath, and obtain a master equation for the
dynamics of heat transfer. The damping rates in the master equation are related
to the lifetimes of localized plasmons in the nanoparticles. We study the
dynamics towards the steady state and establish connection with the standard
theory of heat transfer in steady state. For strongly coupled nano particles we
predict Rabi oscillations in the mean occupation number of surface plasmons in
each nano particle
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