Neural Diffusion Models

Diffusion models have shown remarkable performance on many generative tasks. Despite recent success, most diffusion models are restricted in that they only allow linear transformation of the data distribution. In contrast, broader family of transformations can potentially help train generative distributions more efficiently, simplifying the reverse process and closing the gap between the true negative log-likelihood and the variational approximation. In this paper, we present Neural Diffusion Models (NDMs), a generalization of conventional diffusion models that enables defining and learning time-dependent non-linear transformations of data. We show how to optimise NDMs using a variational bound in a simulation-free setting. Moreover, we derive a time-continuous formulation of NDMs, which allows fast and reliable inference using off-the-shelf numerical ODE and SDE solvers. Finally, we demonstrate the utility of NDMs with learnable transformations through experiments on standard image generation benchmarks, including CIFAR-10, downsampled versions of ImageNet and CelebA-HQ. NDMs outperform conventional diffusion models in terms of likelihood and produce high-quality samples

Geometric phase and o-mode blue shift in a chiral anisotropic medium inside a Fabry-P\'erot cavity

Anomalous spectral shift of transmission peaks is observed in a Fabry--P\'erot cavity filled with a chiral anisotropic medium. The effective refractive index value resides out of the interval between the ordinary and the extraordinary refractive indices. The spectral shift is explained by contribution of a geometric phase. The problem is solved analytically using the approximate Jones matrix method, numerically using the accurate Berreman method and geometrically using the generalized Mauguin--Poincar\'e rolling cone method. The $o$-mode blue shift is measured for a 4-methoxybenzylidene-4'-$n$-butylaniline twisted--nematic layer inside the Fabry--P\'erot cavity. The twist is electrically induced due to the homeoplanar--twisted configuration transition in an ionic-surfactant-doped liquid crystal layer. Experimental evidence confirms the validity of the theoretical model.Comment: the text is available both in English (Timofeev2015en.tex) and in Russian (download: other formats - source - Timofeev2015ru.tex, Timofeev2015rus.pdf

Spontaneous Magnetisation in a Quantum Wire

An existence of predominant symmetrical spin configuration (spin polarised phase) and "diluted" density of states (pseudo-gap) in a layer under the Fermi level in a quantum wire is predicted. The condition of cross-over from non-polarised phase to polarised one was derived. The transition occurs for sufficiently low electron density in a wire and is accompanied by an acute decrease of electron density of states near the Fermi level.It may result in a corresponding decrease of conductance. A similar effect may exist in a two-dimensional electron gas.Comment: 8 pages, 1 figur

Diagnosis of heart failure with preserved and midrange ejection fraction in medical practice

The article summarizes the data in the modern literature about know diagnosis and treatment of heart failure with preserved ejection fraction. Diagnosis of heart failure with nomaland midrange ejection fraction is frequently challenging and relies upon careful clinical evaluation, tissue Doppler imaging, echo-Doppler cardiography, the level of natriuretic peptides and invasive haemodynamic assessment.В обзоре обобщены данные современной литературы по диагностике сердечной недостаточности с нормальной и промежуточной фракцией выброса. Более половины пациентов с симптомами сердечной недостаточности имеют фракцию выброса более 40%, что не является значительным снижением сократимости миокарда. Подтверждение диагноза ХСН в данном случае сложно и основывается на тщательной оценке клинических проявлений, результатов тканевого допплера, допплер-эхокардиографии, уровня биомаркеров, а также инвазивных методов оценки гемодинамики

Manifestation of type 2 diabetes mellitus in the background of COVID-19: review and clinical case

The article presents a literature review of clinical data on the manifestation of type 2 diabetes mellitus against the background of coronavirus infection COVID-19, COVID-19 is considered as a possible cause of type 2 diabetes. A clinical case of a patient with coronavirus infection and newly diagnosed type 2 diabetes mellitus was presentedВ статье приведен литературный обзор клинических данных о манифестации сахарного диабета 2 типа на фоне коронавирусной инфекции COVID-19, COVID-19 рассмотрен как возможная причина возникновения сахарного диабета 2 типа. Приведен клинический случай пациентки с коронавирусной инфекцией и впервые диагностированным сахарным диабетом 2 типа

Social and professional psychological potrait of the residents as basis of their training proffesional activity

the article presents the results of the study of residents in order to compile a social and professional -psychological portrait as the basis of training for professional activities of medical specialistsв статье представлены результаты исследования ординаторов с целью составления социально и профессионально- психологического портрета как подготовки к профессиональной деятельности медицинских специалисто