123 research outputs found
Non-perturbative dynamics of hot non-Abelian gauge fields: beyond leading log approximation
Many aspects of high-temperature gauge theories, such as the electroweak
baryon number violation rate, color conductivity, and the hard gluon damping
rate, have previously been understood only at leading logarithmic order (that
is, neglecting effects suppressed only by an inverse logarithm of the gauge
coupling). We discuss how to systematically go beyond leading logarithmic order
in the analysis of physical quantities. Specifically, we extend to
next-to-leading-log order (NLLO) the simple leading-log effective theory due to
Bodeker that describes non-perturbative color physics in hot non-Abelian
plasmas. A suitable scaling analysis is used to show that no new operators
enter the effective theory at next-to-leading-log order. However, a NLLO
calculation of the color conductivity is required, and we report the resulting
value. Our NLLO result for the color conductivity can be trivially combined
with previous numerical work by G. Moore to yield a NLLO result for the hot
electroweak baryon number violation rate.Comment: 20 pages, 1 figur
Epigenetic evolution and lineage histories of chronic lymphocytic leukaemia
Genetic and epigenetic intra-tumoral heterogeneity cooperate to shape the evolutionary course of cancer1. Chronic lymphocytic leukaemia (CLL) is a highly informative model for cancer evolution as it undergoes substantial genetic diversification and evolution after therapy2,3. The CLL epigenome is also an important disease-defining feature4,5, and growing populations of cells in CLL diversify by stochastic changes in DNA methylation known as epimutations6. However, previous studies using bulk sequencing methods to analyse the patterns of DNA methylation were unable to determine whether epimutations affect CLL populations homogeneously. Here, to measure the epimutation rate at single-cell resolution, we applied multiplexed single-cell reduced-representation bisulfite sequencing to B cells from healthy donors and patients with CLL. We observed that the common clonal origin of CLL results in a consistently increased epimutation rate, with low variability in the cell-to-cell epimutation rate. By contrast, variable epimutation rates across healthy B cells reflect diverse evolutionary ages across the trajectory of B cell differentiation, consistent with epimutations serving as a molecular clock. Heritable epimutation information allowed us to reconstruct lineages at high-resolution with single-cell data, and to apply this directly to patient samples. The CLL lineage tree shape revealed earlier branching and longer branch lengths than in normal B cells, reflecting rapid drift after the initial malignant transformation and a greater proliferative history. Integration of single-cell bisulfite sequencing analysis with single-cell transcriptomes and genotyping confirmed that genetic subclones mapped to distinct clades, as inferred solely on the basis of epimutation information. Finally, to examine potential lineage biases during therapy, we profiled serial samples during ibrutinib-associated lymphocytosis, and identified clades of cells that were preferentially expelled from the lymph node after treatment, marked by distinct transcriptional profiles. The single-cell integration of genetic, epigenetic and transcriptional information thus charts the lineage history of CLL and its evolution with therapy
Specific heat and heat conductivity of the BaTiO3 polycrystalline films with the thickness in the range 20 - 1100 nm
Thermal properties - specific heat and heat conductivity coefficient - of
polycrystalline BaTiO3 films on massive substrates were studied as a function
of the temperature and the film thickness by ac-hot probe method. The anomalies
of specific heat with decreasing of the film thickness from 1100 to 20 nm
revealed the reducing of critical temperature (Tc) and excess entropy of the
ferroelectric phase transition, which becomes diffused. The critical thickness
of the film at which Tc = 0 estimated as 2.5 nm.Comment: 12 pages, 7 figures, 2 tables, 450kb; submitted to J.Phys.:Cond.Mat
Dimebon Does Not Ameliorate Pathological Changes Caused by Expression of Truncated (1–120) Human Alpha-Synuclein in Dopaminergic Neurons of Transgenic Mice
Background: Recent clinical studies have demonstrated that dimebon, a drug originally designed and used as a non-selective antihistamine, ameliorates symptoms and delays progress of mild to moderate forms of Alzheimer’s and Huntington’s diseases. Although the mechanism of dimebon action on pathological processes in degenerating brain is elusive, results of studies carried out in cell cultures and animal models suggested that this drug might affect the process of pathological accumulation and aggregation of various proteins involved in the pathogenesis of proteinopathies. However, the effect of this drug on the pathology caused by overexpression and aggregation of alpha-synuclein, including Parkinson’s disease (PD), has not been assessed. Objective: To test if dimebon affected alpha-synuclein-induced pathology using a transgenic animal model. Methods: We studied the effects of chronic dimebon treatment on transgenic mice expressing the C-terminally truncated (1–120) form of human alpha-synuclein in dopaminergic neurons, a mouse model that recapitulates several biochemical, histopathological and behavioral characteristics of the early stage of PD. Results: Dimebon did not improve balance and coordination of aging transgenic animals or increase the level of striatal dopamine, nor did it prevent accumulation of alpha-synuclein in cell bodies of dopaminergic neurons. Conclusion: Our observations suggest that in the studied model of alpha-synucleinopathy dimebon has very limited effect on certain pathological alterations typical of PD and related diseases
Lattice Chern-Simons Number Without Ultraviolet Problems
We develop a topological method of measuring Chern-Simons number change in
the real time evolution of classical lattice SU(2) and SU(2) Higgs theory. We
find that the Chern-Simons number diffusion rate per physical 4-volume is very
heavily suppressed in the broken phase, and that it decreases with lattice
spacing in pure Yang-Mills theory, although not as quickly as predicted by
Arnold, Son, and Yaffe.Comment: 26 pages including 6 figures, uses psfig. Corrected for an algebra
error in the original draft of hep-lat/9610013; minor rewriting and more
analysi
Measuring the Broken Phase Sphaleron Rate Nonperturbatively
We present details for a method to compute the broken phase sphaleron rate
(rate of hot baryon number violation below the electroweak phase transition)
nonperturbatively, using a combination of multicanonical and real time lattice
techniques. The calculation includes the ``dynamical prefactor,'' which
accounts for prompt recrossings of the sphaleron barrier. The prefactor depends
on the hard thermal loops, getting smaller with increasing Debye mass; but for
realistic Debye masses the effect is not large. The baryon number erasure rate
in the broken phase is slower than a perturbative estimate by about exp(-3.6).
Assuming the electroweak phase transition has enough latent heat to reheat the
universe to the equilibrium temperature, baryon number is preserved after the
phase transition if the ratio of (``dimensionally reduced'' thermal) scalar to
gauge couplings (lambda / g^2) is less than .037.Comment: 41 pages, 13 figures included with psfig. Some wordings clarified,
nothing substantial change
Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC
CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/ and 500~MeV protons up to a fluence of . We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to and decreases by 40~\% at . Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radiation hard to 24~GeV/ and 500~MeV protons up to at least without signal loss
Severe traumatic injury during long duration spaceflight: Light years beyond ATLS
Traumatic injury strikes unexpectedly among the healthiest members of the human population, and has been an inevitable companion of exploration throughout history. In space flight beyond the Earth's orbit, NASA considers trauma to be the highest level of concern regarding the probable incidence versus impact on mission and health. Because of limited resources, medical care will have to focus on the conditions most likely to occur, as well as those with the most significant impact on the crew and mission. Although the relative risk of disabling injuries is significantly higher than traumatic deaths on earth, either issue would have catastrophic implications during space flight. As a result this review focuses on serious life-threatening injuries during space flight as determined by a NASA consensus conference attended by experts in all aspects of injury and space flight
Менингококковая инфекция у детей в период 2012–2021 гг. Основные итоги ретроспективного многоцентрового исследования, проблемы сегодняшнего дня
The heavy burden of meningococcal infection is associated not only with life-threatening complications in the acute period and high mortality in invasive forms of the disease, but also with severe consequences in survivors, who are not recorded in our country.The aim of study: to analyze clinical manifestations, complications of the acute period and outcomes of invasive forms of meningococcal disease in children in various regions of the Russian Federation.Materials and methods: an analysis of data from 1327 inpatient medical records of children with an invasive meningococcal infection from 14 regional centers of the Russian Federation for 2012-2021 was carried out (28.3% of cases of the disease in children in the represented federal districts).Results: it was found that young children predominated among the patients – the median was 27.4 (10.7-70.4) months. Complications of the acute period, often combined, were observed in 47.6% of cases. The development of septic shock was noted in 30.4%, Waterhouse-Friderichsen syndrome in 6.6%, carditis in 2.9%, cerebral edema in 15.7%, arthritis in 1.4% of cases; the formation of hydrocephalus, subdural effusion, sensorineural hearing loss in 1.8%, 0.6%, 1% of children, respectively. The presence of soft tissue necrosis requiring surgical intervention was noted in 3.5% of cases. Mortality rate was 10.1%. At the time of discharge from the hospital, 30% of children had complications associated with meningococcal infection: organ dysfunction/ failure in 13.2% of patients (severe in 1.3%), cerebral insufficiency in 19.6%; severe psycho-neurological deficits, sensorineural hearing loss, problems associated with the need for orthopedic/surgical interventions accounted for 0.7%, 0.6% and 0.8%, respectively.Conclusion. Considering the epidemiological features of meningococcal infection – the risk of a sharp increase in morbidity in short periods of time, the life-threatening nature of the disease itself, it is necessary to remain alert to these risks and take all possible measures to prevent the disease using all available means, the most effective of which is vaccine prevention.Тяжелое бремя менингококковой инфекции связано не только с жизнеугрожающими осложнениями острого периода и высокой летальностью при генерализованных формах заболевания, но и с тяжелыми последствиями у выживших, учет которых в нашей стране не ведется.Цель: проведение анализа клинических проявлений, осложнений острого периода и исходов генерализованных форм менингококковой инфекции у детей в различных регионах Российской Федерации.Материалы и методы: проведен анализ данных 1327 медицинских карт (форма 003/у) детей с генерализованной формой менингококковой инфекции из 14 региональных центров Российской Федерации за 2012– 2021 гг. (28,3% случаев заболевания у детей в представляемых федеральных округах).Результаты: установлено, что среди больных преобладали дети раннего возраста – медиана составила 27,4 (10,7–70,4) месяцев. Осложнения, часто сочетанные, в остром периоде заболевания наблюдались в 47,6% случаев: септический шок в 30,4%, синдром Уотерхауза – Фридериксена в 6,6%, кардит в 2,9%, отек головного мозга в 15,7%, артриты в 1,4%, гидроцефалия в 1,8%, сенсоневральная тугоухость в 1%, субдуральный выпот в 0,6% случаев. Наличие некрозов мягких тканей, требовавших хирургического вмешательства, отмечено в 3,5% случаев. Летальность составила 10,1%. На момент выписки из стационара у 30% детей выявлялись осложнения, в том числе выраженная органная дисфункция в 1,3%, грубый психоневрологический дефицит, сенсоневральная тугоухость; осложнения, требующие проведения ортопедических/хирургических вмешательств, составили 0,7%, 0,6% и 0,8% соответственно.Анализ полученных данных позволил вскрыть существующие проблемы, касающиеся клинической и этиологической диагностики заболевания, возможностей выявления осложнений острого периода и учета последствий генерализованных форм менингококковой инфекции.Заключение. Учитывая эпидемиологические особенности менингококковой инфекции (риск резкого подъема заболеваемости в короткие временные промежутки, жизнеугрожающий характер самого заболевания), необходимо сохранять настороженность в отношении данных рисков и предпринимать все возможные меры для профилактики заболевания с использованием всех доступных средств, наиболее эффективным из которых является вакцинопрофилактика
Traffic incident duration prediction via a deep learning framework for text description encoding
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