Development of Human Pancreatic Innervation

Human pancreatic innervation is of particular interest due to its possible role in the pathogenesis of such diseases as diabetes mellitus, pancreatitis and pancreatic cancer. Despite the clinical importance, data concerning pancreatic innervation during human ontogeny and in various disorders are very limited. In this chapter, we present a review on human pancreatic autonomic innervation on the basis of the literature data and our previous results. Special attention is paid to the innervation of the endocrine pancreas. Gradual branching of neural network was seen during human pancreatic development. Innervation of the foetal pancreas is more abundant than in adults. In agreement with previous observations, we have revealed a close integration and similarity between endocrine cells and nervous elements in the developing human pancreas. Moreover, simultaneous interactions between the nervous system components, epithelial cells and endocrine cells were detected in the pancreas during prenatal human development. It has been suggested that pancreatic innervation plays an important role not only in regulation of endocrine and exocrine activity but also in normal islet morphogenesis

Stellar Surface Magnetic Fields Impact Limb Darkening

Stars appear darker at their limbs than at their disk centers because at the limb we are viewing the higher and cooler layers of stellar photospheres. Limb darkening derived from state-of-the-art stellar atmosphere models systematically fails to reproduce recent transiting exoplanet light curves from the Kepler, TESS, and JWST telescopes -- stellar brightness obtained from measurements drops less steeply towards the limb than predicted by models. All previous models assumed atmosphere devoid of magnetic fields. Here we use our new stellar atmosphere models computed with the 3D radiative magneto-hydrodynamic code MURaM to show that small-scale concentration of magnetic fields on the stellar surface affect limb darkening at a level that allows us to explain the observations. Our findings provide a way forward to improve the determination of exoplanet radii and especially the transmission spectroscopy analysis for transiting planets, which relies on a very accurate description of stellar limb darkening from the visible through the infrared. Furthermore, our findings imply that limb darkening allows measuring the small-scale magnetic field on stars with transiting planets.Comment: 19 pages, 6 figures This is the submission version of manuscript to Nature Astronom

Eclipses observed by LYRA - a sensitive tool to test the models for the solar irradiance

We analyze the light curves of the recent solar eclipses measured by the Herzberg channel (200-220 nm) of the Large Yield RAdiometer (LYRA) onboard PROBA-2. The measurements allow us to accurately retrieve the center- to-limb variations (CLV) of the solar brightness. The formation height of the radiation depends on the observing angle so the examination of the CLV provide information about a broad range of heights in the solar atmosphere. We employ the 1D NLTE radiative transfer COde for Solar Irradiance (COSI) to model the measured light curves and corresponding CLV dependencies. The modeling is used to test and constrain the existing 1D models of the solar atmosphere, e.g. the temperature structure of the photosphere and the treatment of the pseudo- continuum opacities in the Herzberg continuum range. We show that COSI can accurately reproduce not only the irradiance from the entire solar disk, but also the measured CLV. It hence can be used as a reliable tool for modeling the variability of the spectral solar irradiance.Comment: 19 pages, 9 figures, Solar Physic

Recent variability of the solar spectral irradiance and its impact on climate modelling

International audienceThe lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier SSI observations and models provided a qualitatively consistent picture of the SSI variability, recent measurements by the SORCE (SOlar Radiation and Climate Experiment) satellite suggest a significantly stronger variability in the ultraviolet (UV) spectral range and changes in the visible and near-infrared (NIR) bands in anti-phase with the solar cycle. A number of recent chemistry-climate model (CCM) simulations have shown that this might have significant implications on the Earth's atmosphere. Motivated by these results, we summarize here our current knowledge of SSI variability and its impact on Earth's climate.We present a detailed overview of existing SSI measurements and provide thorough comparison of models available to date. SSI changes influence the Earth's atmosphere, both directly, through changes in shortwave (SW) heating and therefore, temperature and ozone distributions in the stratosphere, and indirectly, through dynamical feedbacks. We investigate these direct and indirect effects using several state-of-the art CCM simulations forced with measured and modelled SSI changes. A unique asset of this study is the use of a common comprehensive approach for an issue that is usually addressed separately by different communities.We show that the SORCE measurements are difficult to reconcile with earlier observations and with SSI models. Of the five SSI models discussed here, specifically NRLSSI (Naval Research Laboratory Solar Spectral Irradiance), SATIRE-S (Spectral And Total Irradiance REconstructions for the Satellite era), COSI (COde for Solar Irradiance), SRPM (Solar Radiation Physical Modelling), and OAR (Osservatorio Astronomico di Roma), only one shows a behaviour of the UV and visible irradiance qualitatively resembling that of the recent SORCE measurements. However, the integral of the SSI computed with this model over the entire spectral range does not reproduce the measured cyclical changes of the total solar irradiance, which is an essential requisite for realistic evaluations of solar effects on the Earth's climate in CCMs.We show that within the range provided by the recent SSI observations and semi-empirical models discussed here, the NRLSSI model and SORCE observations represent the lower and upper limits in the magnitude of the SSI solar cycle variation.The results of the CCM simulations, forced with the SSI solar cycle variations estimated from the NRLSSI model and from SORCE measurements, show that the direct solar response in the stratosphere is larger for the SORCE than for the NRLSSI data. Correspondingly, larger UV forcing also leads to a larger surface response.Finally, we discuss the reliability of the available data and we propose additional coordinated work, first to build composite SSI data sets out of scattered observations and to refine current SSI models, and second, to run coordinated CCM experiments

Вложенное преобразование с сохранением семантики исходных данных

In the modern world, the data used to describe objects is often presented as sparse vectors with a large number of features. Working with them can be computationally inefficient, and often leads to overfitting; therefore, the data dimension reduction algorithms are used, one of which is auto encoders. In this article, we propose a new approach for evaluating the properties of the obtained vectors of lower dimension, as well as a loss function based on this approach. The idea of the suggested loss function is to evaluate the quality of preserving the semantic structure in the embedding space, and to add that metric to loss function to save object relations in the embedding space and thus save more useful information about objects. The results obtained show that using a combination of the mean squared loss function together with the suggested one allows to improve the quality of the embeddings.В современном мире данные, используемые для описания объектов, часто представлены в виде разряженных векторов с большим количеством признаков. Работа с такими данными является вычислительно неэффективной, что зачастую приводит к переобучению при моделировании. Поэтому используются алгоритмы понижения размерности данных, одними из которых являются автокодировщики. В статье предложен новый подход для оценки свойств полученных векторов меньшей размерности, а также основанная на этом подходе функция потерь. Идея предложенной функции потерь состоит в вычислении качества сохранения семантической структуры в пространстве вложений и добавлении этой метрики в функцию потерь, что позволяет сохранить отношения объектов в пространстве вложений и таким образом сохранить больше полезной информации об объектах. Полученные результаты показывают, что использование комбинации среднеквадратичной функции потерь вместе с предложенной позволяет улучшить качество полученных вложений

Embedding With Preservation of Semantics of the Original Data

В современном мире данные, используемые для описания объектов, часто представлены в виде разряженных векторов с большим количеством признаков. Работа с такими данными является вычислительно неэффективной, что зачастую приводит к переобучению при моделировании. Поэтому используются алгоритмы понижения размерности данных, одними из которых являются автокодировщики. В статье предложен новый подход для оценки свойств полученных векторов меньшей размерности, а также основанная на этом подходе функция потерь. Идея предложенной функции потерь состоит в вычислении качества сохранения семантической структуры в пространстве вложений и добавлении этой метрики в функцию потерь, что позволяет сохранить отношения объектов в пространстве вложений и таким образом сохранить больше полезной информации об объектах. Полученные результаты показывают, что использование комбинации среднеквадратичной функции потерь вместе с предложенной позволяет улучшить качество полученных вложений.In the modern world, the data used to describe objects is often presented as sparse vectors with a large number of features. Working with them can be computationally inefficient, and often leads to overfitting; therefore, the data dimension reduction algorithms are used, one of which is auto encoders. In this article, we propose a new approach for evaluating the properties of the obtained vectors of lower dimension, as well as a loss function based on this approach. The idea of the suggested loss function is to evaluate the quality of preserving the semantic structure in the embedding space, and to add that metric to loss function to save object relations in the embedding space and thus save more useful information about objects. The results obtained show that using a combination of the mean squared loss function together with the suggested one allows to improve the quality of the embeddings

Detection of Solar Rotational Variability in the LYRA 190 - 222 nm Spectral Band

We analyze the variability of the spectral solar irradiance during the period from 7 January, 2010 until 20 January, 2010 as measured by the Herzberg channel (190-222 nm) of the Large Yield RAdiometer (LYRA) onboard PROBA2. In this period of time observations by the LYRA nominal unit experienced degradation and the signal produced by the Herzberg channel frequently jumped from one level to another. Both these factors significantly complicates the analysis. We present the algorithm which allowed us to extract the solar variability from the LYRA data and compare the results with SORCE/SOLSTICE measurements and with modeling based on the Code for the Solar Irradiance (COSI)

Influence of р-thyrozol on the morphology and antioxidant-prooxidant balance in prostate of rats at sulpiride-induced benign prostatic hyperplasia

The aim of the research was to study the influence of p-thyrozol on the morphology and antioxidant-prooxidant balance in prostate of rats at sulpiride-induced benign prostatic hyperplasia. It was found that introduction of p-thyrozol promoted thwarting progress of pathological process that was proved by less degree of manifestation of proliferative processes in epithelium and of cellular infiltration of stroma. In addition, increase of antioxidant reserve of gland was registered

The Measurement of Solar Diameter and Limb Darkening Function with the Eclipse Observations

The Total Solar Irradiance varies over a solar cycle of 11 years and maybe over cycles with longer period. Is the solar diameter variable over time too? We introduce a new method to perform high resolution astrometry of the solar diameter from the ground, through the observations of eclipses by reconsidering the definition of the solar edge. A discussion of the solar diameter and its variations must be linked to the Limb Darkening Function (LDF) using the luminosity evolution of a Baily's Bead and the profile of the lunar limb available from satellite data. This approach unifies the definition of solar edge with LDF inflection point for eclipses and drift-scan or heliometric methods. The method proposed is applied for the videos of the eclipse in 15 January 2010 recorded in Uganda and in India. The result shows light at least 0.85 arcsec beyond the inflection point, and this suggests to reconsider the evaluations of the historical eclipses made with naked eye.Comment: 16 pages, 11 figures, accepted in Solar Physics. arXiv admin note: text overlap with arXiv:astro-ph/0601109 by other author

The Maunder minimum (1645-1715) was indeed a grand minimum: a reassessment of multiple datasets

Aims. Although the time of the Maunder minimum (1645–1715) is widely known as a period of extremely low solar activity, it is still being debated whether solar activity during that period might have been moderate or even higher than the current solar cycle (number 24). We have revisited all existing evidence and datasets, both direct and indirect, to assess the level of solar activity during the Maunder minimum. Methods. We discuss the East Asian naked-eye sunspot observations, the telescopic solar observations, the fraction of sunspot active days, the latitudinal extent of sunspot positions, auroral sightings at high latitudes, cosmogenic radionuclide data as well as solar eclipse observations for that period. We also consider peculiar features of the Sun (very strong hemispheric asymmetry of the sunspot location, unusual differential rotation and the lack of the K-corona) that imply a special mode of solar activity during the Maunder minimum. Results. The level of solar activity during the Maunder minimum is reassessed on the basis of all available datasets. Conclusions. We conclude that solar activity was indeed at an exceptionally low level during the Maunder minimum. Although the exact level is still unclear, it was definitely lower than during the Dalton minimum of around 1800 and significantly below that of the current solar cycle #24. Claims of a moderate-to-high level of solar activity during the Maunder minimum are rejected with a high confidence level