67 research outputs found
О прогнозировании сроков навигации на основе цепей Маркова
The transport network in the regions of the North of theRussian Federationbasically remains seasonal (waterways, winter roads). The duration of river shipping season, depending on the climatic conditions, is 110–160 days, and the time of operation of winter roads varies within 120–210 days. Under these conditions, the accuracy of predicting the beginning and end of shipping season for the northern rivers plays a very important role. The article proposes a method for forecasting the duration of ice phenomena in the areas of shipping routes based on the use of the mathematical apparatus of Markov chains. An estimate of probability of an accurate forecast is given, taking into account the conformity with Bayes theorem and related dependencies. Verification of the method on the basis of real data proved that the forecast accuracy and probability of its implementation were sufficient for timely and effective organisation of preparatory operations for next shipping season on northern navigable rivers.Транспортная сеть в районах Севера России в основном остаётся сезонной (водные пути, автозимники). Продолжительность навигации на реках составляет в зависимости от природно-климатических условий 110–160 суток, а время эксплуатации автозимников колеблется в пределах 120–210 суток. В этих условиях весьма важную роль играет точность прогноза начала и окончания навигации на северных реках. В статье предложен метод прогнозирования сроков ледовых явлений в зонах судоходных путей сообщения на основе использования математического аппарата цепей Маркова. Дана оценка вероятности точного прогноза с учётом соответствия теореме Байеса и сопутствующих зависимостей
Реновация подвижного состава: муниципальный лизинг и финансирование обновления
The fleet of urban passenger transport has a constantly growing physical and moral deterioration. And it is necessary to have time to refurbish it and to replace. However, this task is becoming a problem due to the lack of financial resources. Previously, in Russia renewal was carried out at the expense of depreciation of fixed assets of transport enterprises. Now according to regulations it has to be done at the expense of profit, which entails certain losses and requires to look for reliable sources of targeted funding. The article refers to the study of possible sources of funding of renewal of urban passenger vehicle fleet, their optimal use, and their impact on the development of urban mass transit systems. Target budget funding and depreciation deductions, private public partnership in the form of so called municipal leasing are considered with regard to Russian urban public transport.Парк подвижного состава городского пассажирского транспорта имеет постоянно растущий физический и моральный износ. И надо своевременно успевать его реанимировать, обновлять. Однако эта задача превращается в проблему из-за дефицита денежных ресурсов. Ранее реновация осуществлялась за счёт амортизации основных средств транспортных предприятий. Теперь это предписано делать за счёт прибыли, что влечёт за собой определённые потери и требует искать надёжные источники целевого финансирования. Именно о подобного рода источниках, способах их использования, поддержке тем самым развития пассажирского транспорта в городах, собственно, и идёт речь в публикуемой статье
A Genome-Wide Metabolic QTL Analysis in Europeans Implicates Two Loci Shaped by Recent Positive Selection
We have performed a metabolite quantitative trait locus (mQTL) study of the 1H nuclear magnetic resonance spectroscopy (1H NMR) metabolome in humans, building on recent targeted knowledge of genetic drivers of metabolic regulation. Urine and plasma samples were collected from two cohorts of individuals of European descent, with one cohort comprised of female twins donating samples longitudinally. Sample metabolite concentrations were quantified by 1H NMR and tested for association with genome-wide single-nucleotide polymorphisms (SNPs). Four metabolites' concentrations exhibited significant, replicable association with SNP variation (8.6×10−11<p<2.8×10−23). Three of these—trimethylamine, 3-amino-isobutyrate, and an N-acetylated compound—were measured in urine. The other—dimethylamine—was measured in plasma. Trimethylamine and dimethylamine mapped to a single genetic region (hence we report a total of three implicated genomic regions). Two of the three hit regions lie within haplotype blocks (at 2p13.1 and 10q24.2) that carry the genetic signature of strong, recent, positive selection in European populations. Genes NAT8 and PYROXD2, both with relatively uncharacterized functional roles, are good candidates for mediating the corresponding mQTL associations. The study's longitudinal twin design allowed detailed variance-components analysis of the sources of population variation in metabolite levels. The mQTLs explained 40%–64% of biological population variation in the corresponding metabolites' concentrations. These effect sizes are stronger than those reported in a recent, targeted mQTL study of metabolites in serum using the targeted-metabolomics Biocrates platform. By re-analysing our plasma samples using the Biocrates platform, we replicated the mQTL findings of the previous study and discovered a previously uncharacterized yet substantial familial component of variation in metabolite levels in addition to the heritability contribution from the corresponding mQTL effects
A Genome-Wide Metabolic QTL Analysis in Europeans Implicates Two Loci Shaped by Recent Positive Selection
We have performed a metabolite quantitative trait locus (mQTL) study of the 1H nuclear magnetic resonance spectroscopy (1H NMR) metabolome in humans, building on recent targeted knowledge of genetic drivers of metabolic regulation. Urine and plasma samples were collected from two cohorts of individuals of European descent, with one cohort comprised of female twins donating samples longitudinally. Sample metabolite concentrations were quantified by 1H NMR and tested for association with genome-wide single-nucleotide polymorphisms (SNPs). Four metabolites' concentrations exhibited significant, replicable association with SNP variation (8.6×10−11<p<2.8×10−23). Three of these—trimethylamine, 3-amino-isobutyrate, and an N-acetylated compound—were measured in urine. The other—dimethylamine—was measured in plasma. Trimethylamine and dimethylamine mapped to a single genetic region (hence we report a total of three implicated genomic regions). Two of the three hit regions lie within haplotype blocks (at 2p13.1 and 10q24.2) that carry the genetic signature of strong, recent, positive selection in European populations. Genes NAT8 and PYROXD2, both with relatively uncharacterized functional roles, are good candidates for mediating the corresponding mQTL associations. The study's longitudinal twin design allowed detailed variance-components analysis of the sources of population variation in metabolite levels. The mQTLs explained 40%–64% of biological population variation in the corresponding metabolites' concentrations. These effect sizes are stronger than those reported in a recent, targeted mQTL study of metabolites in serum using the targeted-metabolomics Biocrates platform. By re-analysing our plasma samples using the Biocrates platform, we replicated the mQTL findings of the previous study and discovered a previously uncharacterized yet substantial familial component of variation in metabolite levels in addition to the heritability contribution from the corresponding mQTL effects
Transcriptomic profiling of host-parasite interactions in the microsporidian <i>Trachipleistophora hominis</i>
BACKGROUND: Trachipleistophora hominis was isolated from an HIV/AIDS patient and is a member of a highly successful group of obligate intracellular parasites. METHODS: Here we have investigated the evolution of the parasite and the interplay between host and parasite gene expression using transcriptomics of T. hominis-infected rabbit kidney cells. RESULTS: T. hominis has about 30 % more genes than small-genome microsporidians. Highly expressed genes include those involved in growth, replication, defence against oxidative stress, and a large fraction of uncharacterised genes. Chaperones are also highly expressed and may buffer the deleterious effects of the large number of non-synonymous mutations observed in essential T. hominis genes. Host expression suggests a general cellular shutdown upon infection, but ATP, amino sugar and nucleotide sugar production appear enhanced, potentially providing the parasite with substrates it cannot make itself. Expression divergence of duplicated genes, including transporters used to acquire host metabolites, demonstrates ongoing functional diversification during microsporidian evolution. We identified overlapping transcription at more than 100 loci in the sparse T. hominis genome, demonstrating that this feature is not caused by genome compaction. The detection of additional transposons of insect origin strongly suggests that the natural host for T. hominis is an insect. CONCLUSIONS: Our results reveal that the evolution of contemporary microsporidian genomes is highly dynamic and innovative. Moreover, highly expressed T. hominis genes of unknown function include a cohort that are shared among all microsporidians, indicating that some strongly conserved features of the biology of these enormously successful parasites remain uncharacterised. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1989-z) contains supplementary material, which is available to authorized users
"The End of Immortality!" Eternal Life and the Makropulos Debate
Responding to a well-known essay by Bernard Williams, philosophers (and a few theologians) have engaged in what I call “the Makropulos debate,” a debate over whether immortality—“living forever”—would be desirable for beings like us. Lacking a firm conceptual grounding in the religious contexts from which terms such as “immortality” and “eternal life” gain much of their sense, the debate has consisted chiefly in a battle of speculative fantasies. Having presented my four main reasons for this assessment, I examine an alternative and neglected conception, the idea of eternal life as a present possession, derived in large part from Johannine Christianity. Without claiming to argue for the truth of this conception, I present its investigation as exemplifying a conceptually fruitful direction of inquiry into immortality or eternal life, one which takes seriously the religious and ethical surroundings of these concepts
The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome.
X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X's gene content, gene expression, and evolution
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