340 research outputs found
In vivo Spectroscopy and Imaging of Nitroxide Probes
Book chapter from "Nitroxides - Theory, Experiment and Applications", edited by Alexander I. Kokorin, ISBN 978-953-51-0722-4, Hard cover, 436 pages, InTech, September 12, 2012.
DOI: 10.5772/288
Machine learning technique for morphological classification of galaxies at z<0.1 from the SDSS
Methods. We used different galaxy classification techniques: human labeling,
multi-photometry diagrams, Naive Bayes, Logistic Regression, Support Vector
Machine, Random Forest, k-Nearest Neighbors, and k-fold validation. Results. We
present results of a binary automated morphological classification of galaxies
conducted by human labeling, multiphotometry, and supervised Machine Learning
methods. We applied its to the sample of galaxies from the SDSS DR9 with
redshifts of 0.02 < z < 0.1 and absolute stellar magnitudes of 24m < Mr <
19.4m. To study the classifier, we used absolute magnitudes: Mu, Mg, Mr , Mi,
Mz, Mu-Mr , Mg-Mi, Mu-Mg, Mr-Mz, and inverse concentration index to the center
R50/R90. Using the Support vector machine classifier and the data on color
indices, absolute magnitudes, inverse concentration index of galaxies with
visual morphological types, we were able to classify 316 031 galaxies from the
SDSS DR9 with unknown morphological types. Conclusions. The methods of Support
Vector Machine and Random Forest with Scikit-learn machine learning in Python
provide the highest accuracy for the binary galaxy morphological
classification: 96.4% correctly classified (96.1% early E and 96.9% late L
types) and 95.5% correctly classified (96.7% early E and 92.8% late L types),
respectively. Applying the Support Vector Machine for the sample of 316 031
galaxies from the SDSS DR9 at z < 0.1, we found 141 211 E and 174 820 L types
among them.Comment: 10 pages, 5 figures. The presentation of these results was given
during the EWASS-2017, Symposium "Astroinformatics: From Big Data to
Understanding the Universe at Large". It is vailable through
\url{http://space.asu.cas.cz/~ewass17-soc/Presentations/S14/Dobrycheva_987.pdf
The complete reducibility of some GF(2)A7-modules
It is proved that, if G is a finite group with a nontrivial normal 2-subgroup Q such that G/Q ∼= A 7 and an element of order 5 from G acts freely on Q, then the extension G over Q is splittable, Q is an elementary abelian group, and Q is the direct product of minimal normal subgroups of G each of which is isomorphic, as a G/Q-module, to one of the two 4-dimensional irreducible GF(2)A7-modules that are conjugate with respect to an outer automorphism of the group A7. © 2013 Pleiades Publishing, Ltd
VEXAS: VISTA EXtension to Auxiliary Surveys -- Data Release 2: Machine-learning based classification of sources in the Southern Hemisphere
We present the second public data release (DR) of the VISTA EXtension to
Auxiliary Surveys (VEXAS), where we classify objects into stars, galaxies and
quasars based on an ensemble of machine learning algorithms. The aim of VEXAS
is to build the widest multi-wavelength catalogue, providing reference
magnitudes, colours and morphological information for a large number of
scientific uses. We apply an ensemble of 32 different machine learning models,
based on three different algorithms and on different magnitude sets, training
samples and classification problems on the three VEXAS DR1 optical+infrared
(IR) tables. The tables were created in DR1 cross-matching VISTA near-IR data
with WISE far-IR data and with optical magnitudes from the Dark Energy Survey
(VEXAS-DESW), the Sky Mapper Survey (VEXAS-SMW), and the PanSTARRS (VEXAS-PSW).
We assemble a large table of spectroscopically confirmed objects (415 628
unique objects), based on the combination of 6 different spectroscopic surveys
that we use for training. We develop feature imputation to classify also
objects for which magnitudes in one or more bands are missing. We classify in
total ~90 million objects in the Southern Hemisphere. Among these,~62.9M
(~52.6M) are classified as 'high confidence' ('secure') stars, ~920k (~750k) as
'high confidence' ('secure') quasars and ~34.8M (~34.1M) as 'high confidence'
('secure') galaxies, with probabilities (). The density of high-confidence extragalactic objects varies
strongly with the survey depth: at , there are
111/deg quasars in the VEXAS-DESW footprint and 103/deg in the
VEXAS-PSW footprint, while only 10.7/deg in the VEXAS-SM footprint.
Improved depth in the midIR and coverage in the optical and nearIR are needed
for the SM footprint that is not already covered by DESW and PSW.Comment: 25 pages, 18 figures, 8 tables. Accepted for publication on A&A. The
VEXAS tables are publicly available through the ESO Phase 3 here:
https://archive.eso.org/scienceportal/home?data_collection=VEXAS. The DR2
tables update the DR1 with the addition of imputed magnitudes and membership
probabilities to each of the three classe
Microlinear piezo drive experiments
The article embraces the experimental description of the micro linear piezo drive intended for the peripheral cord tensioner in the reflecting surface shape regulator system for large-sized transformable spacecraft antenna reflectors. The research target is the experimental investigation of the micro linear piezo drive to determine the stable oscillatory system operating modes which would include improved energy conversion parameters. The following points are briefly presented: test stand construction-design of the peripheral cord tensioner; the determined frequency characteristics and the identified resonant and actual frequencies of an oscillatory system under inertia load. A series of experiments has been conducted for both different preliminary voltages and inertia mass values
Modeling startup and shutdown transient of the microlinear piezo drive via ANSYS
The article describes the construction-design of the micro linear piezo drive intended for a peripheral cord tensioner in the reflecting surface shape regulator system for large-sized transformable spacecraft antenna reflectors. The research target -the development method of modeling startup and shutdown transient of the micro linear piezo drive. This method is based on application software package ANSYS. The method embraces a detailed description of the calculation stages to determine the operating characteristics of the designed piezo drive. Based on the numerical solutions, the time characteristics of the designed piezo drive are determined
Радиационная обстановка на территории проведения мирного ядерного взрыва «Глобус-1» до выполнения реабилитационных работ
The article provides data on the radiation situation on research results 2008and 2014 in the area adjacent to the site of the peaceful nuclear explosion “Globus-1” before the rehabilitation works (2014—2015), made with a view to removing accidental contamination. The results of the analysis of the dynamics of changes of the radiation situation during the period from 2008 to 2014 year and assess the radiological situation on basic indicators: the values of the dose of technogenic radionuclides content in soil, water and other objects in the environment. On the basis of the research shows that the radiation situation on the territory of the “Globuc-1” has not undergone significant changes from 2008 onwards. An additional dose of man-made exposure of individuals from the population is formed mainly due to external irradiation provided temporary residence on the territory with elevated levels of gamma radiation. As a result of work performed by sealing research wells decreased stem onto the surface of the water with high concentrations of cesium-137, strontium-90 and tritium. Radioactive contamination of the soil to a depth of 1 m, studied in the year 2014, is estimated at 2200 m3 and can be classified as very active and low-level radioactive wastes for which allowed a near-surface burial. Because of the inaccessibility of the area for the removal of soil and remoteness from populated areas considered advisable to arrange the near-surface burial of contaminated soil () directly on the premises of the site.В статье приводятся данные о радиационной обстановке по результатам исследований 2008 и 2014 гг. на территории, прилегающей к месту проведения мирного ядерного взрыва «Глобус-1» перед реабилитационными работами (2014—2015 гг.), выполненными с целью удаления аварийного загрязнения. Рассмотрены результаты анализа динамики изменений радиационной обстановки за период с 2008 по 2014 г. и дана оценка радиационной обстановки по основным показателям: значения мощности дозы, содержание техногенных радионуклидов в почве, воде и других объектах окружающей среды. На основании выполненных исследований показано, что радиационная обстановка на территории объекта «Глобус-1» не претерпела существенных изменений с 2008 г. Доза дополнительного техногенного облучения отдельных лиц из населения формируется в основном за счет внешнего облучения при условии временного пребывания на территории с повышенными уровнями гамма-излучения. В результате выполненных работ по герметизации исследовательской скважины снизился вынос на поверхность воды с высокими концентрациями цезия-137, стронция-90 и трития. Загрязнения радиоактивного грунта на глубину 1 м, исследованные в 2014 г., оцениваются в 2200 м3 и могут быть отнесены к категории очень низкоактивных и низкоактивных радиоактивных отходов, для которых допускается приповерхностное захоронение. Ввиду труднодоступности района для вывоза грунта и отдаленности от населенных пунктов признано целесообразным организовать приповерхностное захоронение загрязненного грунта непосредственно на территории объекта
KiDS0239-3211: A new gravitational quadruple lens candidate
We report the discovery of a candidate to quadrupole gravitationally lensed
system KiDS0239-3211 based on the public data release 3 of the KiDS survey and
machine learning techniques
Concurrent Longitudinal EPR Monitoring of Tissue Oxygenation, Acidosis, and Reducing Capacity in Mouse Xenograft Tumor Models
Tissue oxygenation, extracellular acidity and tissue reducing capacity are among crucial parameters of tumor microenvironment (TME) of significant importance for tumor pathophysiology. In this paper we demonstrate the complementary application of particulate lithium octa-n-butoxy-naphthalocyanine (LiNc-BuO) and soluble nitroxide (NR) paramagnetic probes for monitoring of these TME parameters using electron paramagnetic resonance (EPR) technique. Two different types of therapeutic interventions were studied: hypothermia and systemic administration of metabolically active drug. In summary, the results demonstrate utility of EPR technique for noninvasive concurrent longitudinal monitoring of physiologically relevant chemical parameters of TME in a mouse xenograft tumor models including that under therapeutic intervention
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