2,612 research outputs found
Algebraic treatment of -symmetric coupled oscillators
The purpose of this paper is the discussion of a pair of coupled linear
oscillators that has recently been proposed as a model of a system of two
optical resonators. By means of an algebraic approach we show that the
frequencies of the classical and quantum-mechanical interpretations of the
optical phenomenon are exactly the same. Consequently, if the classical
frequencies are real, then the quantum-mechanical eigenvalues are also real
A study on the minimum number of loci required for genetic evaluation using a finite locus model
For a finite locus model, Markov chain Monte Carlo (MCMC) methods can be used to estimate the conditional mean of genotypic values given phenotypes, which is also known as the best predictor (BP). When computationally feasible, this type of genetic prediction provides an elegant solution to the problem of genetic evaluation under non-additive inheritance, especially for crossbred data. Successful application of MCMC methods for genetic evaluation using finite locus models depends, among other factors, on the number of loci assumed in the model. The effect of the assumed number of loci on evaluations obtained by BP was investigated using data simulated with about 100 loci. For several small pedigrees, genetic evaluations obtained by best linear prediction (BLP) were compared to genetic evaluations obtained by BP. For BLP evaluation, used here as the standard of comparison, only the first and second moments of the joint distribution of the genotypic and phenotypic values must be known. These moments were calculated from the gene frequencies and genotypic effects used in the simulation model. BP evaluation requires the complete distribution to be known. For each model used for BP evaluation, the gene frequencies and genotypic effects, which completely specify the required distribution, were derived such that the genotypic mean, the additive variance, and the dominance variance were the same as in the simulation model. For lowly heritable traits, evaluations obtained by BP under models with up to three loci closely matched the evaluations obtained by BLP for both purebred and crossbred data. For highly heritable traits, models with up to six loci were needed to match the evaluations obtained by BLP
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Yrityksen Tekes-rahoitteisen projektin tilintarkastus
Innovaatiorahoituskeskus Tekes rahoitti vuonna 2016 suomalaisten yritysten toteuttamia projekteja noin 467 miljoonalla eurolla. Useimpien Tekesin tarjoamien rahoituspalvelujen ehtona on rahoituksen tilityksen tarkistuttaminen auktorisoidulla tilintarkastajalla.
Työn tavoitteena on tuottaa Tekes-rahoitteisten projektien tarkastusta varten osin tarkastusta ohjaava dokumentaatiopohja, tarjota opinnäytetyön raporttiosalla dokumentaatiopohjaa tukeva katsaus Tekes-rahoitteisten projektien tarkastukseen ja syventää kirjoittajan vielä kapeaa osaamista projektitarkastuksista. Opinnäytetyössä keskitytään Tekesin yrityksille tarjoamien rahoitusmuotojen tarkastuksen erityispiirteisiin eikä raporttia tai dokumentaatiopohjaa voida soveltaa julkisten toimijoiden projektien tarkastuksiin.
Työ toteutettiin laatien teoriapohja tilintarkastuksen tavoitteista ja eri toimeksiannoista, julkisen rahoituksen ja Tekesin rooleista rahoittajana sekä niistä normeista ja sääntelyistä, jotka koskevat julkisen rahoituksen tilitysten tarkastusta. Teoriapohjan lisäksi tuotettiin luku Tekes-rahoitteisen projektin tarkastuksen teknisestä toteutuksesta osin Tekesin vuoden 2017 yleisten rahoitusehtojen ja tarkastusraporttipohjien sekä auktorisoidun tilintarkastajan ja Tekesin maksatuspalvelujohtajan haastattelujen pohjalta. Tämän osion rinnalla tuotettiin Tekes-rahoitteisten projektien tarkastuksia varten dokumentaatiopohja, joka koottiin kokonaisuudeksi raportin liitteisiin.
Tekesin maksatuspalvelujohtaja Anne Kleemolan haastattelun tuloksena todettiin, etteivät Tekesin nykyiset tarkastusraporttipohjat huomioi erityisehtojen tarkastusta yhtä yksityiskohtaisesti, kuin tarkastusraporttipohjalla olevat muut tarkastuksessa huomioitavat seikat on huomioitu. Kleemola totesi tämän olevan hyödyllinen huomio ja tarkastusraporttipohjiin mahdollisesti kehitettävä asia.
Koska toimeksiantajalle tuotetusta dokumentaatiopohjasta syntyi selkeä runko Tekes-rahoitteisen projektin tarkastukselle, projektitarkastuksien osalta koettiin oman osaamisen syventyneen ja yhteydenotto Tekesiin koettiin myös heidän osaltaan hyödylliseksi, opinnäytetyön voidaan todeta täyttäneen tavoitteensa
One-sided versus two-sided stochastic descriptions
It is well-known that discrete-time finite-state Markov Chains, which are
described by one-sided conditional probabilities which describe a dependence on
the past as only dependent on the present, can also be described as
one-dimensional Markov Fields, that is, nearest-neighbour Gibbs measures for
finite-spin models, which are described by two-sided conditional probabilities.
In such Markov Fields the time interpretation of past and future is being
replaced by the space interpretation of an interior volume, surrounded by an
exterior to the left and to the right.
If we relax the Markov requirement to weak dependence, that is, continuous
dependence, either on the past (generalising the Markov-Chain description) or
on the external configuration (generalising the Markov-Field description), it
turns out this equivalence breaks down, and neither class contains the other.
In one direction this result has been known for a few years, in the opposite
direction a counterexample was found recently. Our counterexample is based on
the phenomenon of entropic repulsion in long-range Ising (or "Dyson") models.Comment: 13 pages, Contribution for "Statistical Mechanics of Classical and
Disordered Systems
Sleep disturbances in tension-type headache and migraine
Current research into the pathogenesis of tension-type headache (TTH) and
migraine is focused on altered nociceptive pain processing. Among the potential factors that
influence sensitization mechanisms, emotional stress, depression, or sleep disorders all have
an essential role: they increase the excitability of nociceptive firing and trigger hyperalgesic
responses. Sleep disturbances and headache disorders share common brain structures and
pathogenic mechanisms and TTH, migraine, and sleep disturbances often occur together;
for example, 50% of individuals who have either TTH or migraine have insomnia. Moreover,
insomnia and poor sleep quality have been associated with a higher frequency and intensity
of headache attacks, supporting the notion that severity and prevalence of sleep problems
correlate with headache burden. It should be noted that the association between headaches
and sleep problems is bidirectional: headache can promote sleep disturbances, and sleep
disturbances can also precede or trigger a headache attack. Therefore, a better understanding
of the factors that affect sleep quality in TTH and migraine can assist clinicians in determining
better and adequate therapeutic programs. In this review, the role of sleep disturbances in
headaches, and the association with depression, emotional stress, and pain sensitivity in
individuals with TTH or migraine are discussed
Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions
Background
Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals.
Results
Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall.
Conclusions
The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions
Pleiotropic functions of the tumor- and metastasis-suppressing Matrix Metalloproteinase-8 in mammary cancer in MMTV-PyMT transgenic mice
Matrix metalloproteinase-8 (MMP-8; neutrophil collagenase) is an important regulator of innate immunity which has onco-suppressive actions in numerous tumor types
A Small Conductance Calcium-Activated K<sup>+</sup> Channel in C. elegans, KCNL-2, Plays a Role in the Regulation of the Rate of Egg-Laying
In the nervous system of mice, small conductance calcium-activated potassium (SK) channels function to regulate neuronal excitability through the generation of a component of the medium afterhyperpolarization that follows action potentials. In humans, irregular action potential firing frequency underlies diseases such as ataxia, epilepsy, schizophrenia and Parkinson's disease. Due to the complexity of studying protein function in the mammalian nervous system, we sought to characterize an SK channel homologue, KCNL-2, in C. elegans, a genetically tractable system in which the lineage of individual neurons was mapped from their early developmental stages. Sequence analysis of the KCNL-2 protein reveals that the six transmembrane domains, the potassium-selective pore and the calmodulin binding domain are highly conserved with the mammalian homologues. We used widefield and confocal fluorescent imaging to show that a fusion construct of KCNL-2 with GFP in transgenic lines is expressed in the nervous system of C. elegans. We also show that a KCNL-2 null strain, kcnl-2(tm1885), demonstrates a mild egg-laying defective phenotype, a phenotype that is rescued in a KCNL-2-dependent manner. Conversely, we show that transgenic lines that overexpress KCNL-2 demonstrate a hyperactive egg-laying phenotype. In this study, we show that the vulva of transgenic hermaphrodites is highly innervated by neuronal processes and by the VC4 and VC5 neurons that express GFP-tagged KCNL-2. We propose that KCNL-2 functions in the nervous system of C. elegans to regulate the rate of egg-laying. © 2013 Chotoo et al
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