167 research outputs found
Machine learning approach to pattern recognition in nuclear dynamics from the ab initio symmetry-adapted no-core shell model
A novel machine learning approach is used to provide further insight into
atomic nuclei and to detect orderly patterns amidst a vast data of large-scale
calculations. The method utilizes a neural network that is trained on ab initio
results from the symmetry-adapted no-core shell model (SA-NCSM) for light
nuclei. We show that the SA-NCSM, which expands ab initio applications up to
medium-mass nuclei by using dominant symmetries of nuclear dynamics, can reach
heavier nuclei when coupled with the machine learning approach. In particular,
we find that a neural network trained on probability amplitudes for -and
-shell nuclear wave functions not only predicts dominant configurations for
heavier nuclei but in addition, when tested for the Ne ground state, it
accurately reproduces the probability distribution. The nonnegligible
configurations predicted by the network provide an important input to the
SA-NCSM for reducing ultra-large model spaces to manageable sizes that can be,
in turn, utilized in SA-NCSM calculations to obtain accurate observables. The
neural network is capable of describing nuclear deformation and is used to
track the shape evolution along the Mg isotopic chain, suggesting a
shape-coexistence that is more pronounced toward the very neutron-rich
isotopes. We provide first descriptions of the structure and deformation of
Si and Mg of interest to x-ray burst nucleosynthesis, and even of
the extremely heavy nuclei such as Er and U, that build
upon first principles considerations.Comment: 10 pages, 9 figure
Investigate the Possibility of Using Phosphorescence in Clinical Oncology as an Early Prognostic Test in Detecting Brain Carcinogenesis.
Phosphorescence is considered one of the non-invasive glioblastoma testing methods based on studying molecular energy and the metabolism of L-tryptophan (Trp) through KP, which provides essential information on regulating immunity and neuronal function. This study aimed to conduct a feasibility study using phosphorescence in clinical oncology as an early prognostic test in detecting Glioblastoma. This study was conducted on 1039 patients who were operated on with follow-up between January 1, 2014, and December 1, 2022, and retrospectively evaluated in participating institutions in Ukraine (the Department of Oncology, Radiation Therapy, Oncosurgery, and Palliative Care at the Kharkiv National Medical University). Method of protein phosphorescence detection included two steps. During the first step, of luminol-dependent phosphorescence intensity in serum was carried out after its activation by the light source, according to the spectrofluorimeter method, as follows. At a temperature of 30 °C, serum drops were dried for 20 min to form a solid film. After that, we put the quartz plate with dried serum in a phosphoroscope of luminescent complex and measured the intensity. With the help of Max-Flux Diffraction Optic Parallel Beam Graded Multilayer Monochromator (Rigaku Americas Corporation) following spectral lines as 297, 313, 334, 365, 404, and 434 nm were distinguished and absorbed by serum film in the form of light quantum. The monochromator exit split width was 0.5 mm. Considering the limitations of each of the non-invasive tools currently available, phosphorescence-based diagnostic methods are ideally integrated into the NIGT platform: a non-invasive approach for visualizing a tumor and its main tumor characteristics in the spatial and temporal order. Because trp is present in virtually every cell in the body, these fluorescent and phosphorescent fingerprints can be used to detect cancer in many different organs. Using phosphorescence, it is possible to create predictive models for GBM in both primary and secondary diagnostics. This will assist clinicians in selecting the appropriate treatment option, monitoring treatment, and adapting to the era of patient-centered precision medicine
Collaborative Online Learning: Plurilingual and Pluricultural Development
Background. The growing importance of international cooperation among universities have increased the number of joint training projects. Common Bologna principles followed by Russian and Spanish tertiary institutions helped perform a pilot study focused on telecollaboration and plurilingual and pluricultural competence implementation. The project aimed at forming plurilingual and pluricultural competence and communicative competence among students studying either English or Spanish or both through the integration of digital technologies into the learning process.Methods. This 7-month study took place in Moscow (Russian Federation) and Valencia (Spain) from November 2019 to June 2020. Participants were university students aged 20–23 from Teaching Training Faculties from Lomonosov Moscow State University and CEU Cardenal Herrera University. The undergraduates who volunteered to participate in the focus group took part in five telecollaboration sessions (March-May 2020). The participants were divided into two mixed (50% Russian and 50% Spanish learners) subgroups and discussed suggested topics during online studentled bilingual sessions. After each online interaction, researchers collected their opinions through questionnaires and discussion with a lecturer.Outcomes. All participants announced that the study gave them a chance to improve their language abilities, update their vocabulary and enhance their intercultural experience. None of the partakers reported having experienced any difficulty doing the project and only regretted that interaction time was too short. Additionally, lecturers were able to test new curricula implementation and assessment procedures.Conclusions. The pilot study was feasible to deliver and there was a clear, satisfactory result with the focus groups participants and teaching staff
CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution observations
The Infrared Spectrograph (IRS) on board the Spitzer Space Telescope observed about 15,000 objects during the cryogenic mission lifetime. Observations provided low-resolution (R~60-127) spectra over ~5-38um and high-resolution (R~600) spectra over ~10-37um. The Cornell Atlas of Spitzer/IRS Sources (CASSIS) was created to provide publishable quality spectra to the community. Low-resolution spectra have been available in CASSIS since 2011, and we present here the addition of the high-resolution spectra. The high-resolution observations represent approximately one third of all staring observations performed with the IRS instrument. While low-resolution observations are adapted to faint objects and/or broad spectral features (e.g., dust continuum, molecular bands), high-resolution observations allow more accurate measurements of narrow features (e.g., ionic emission lines) as well as a better sampling of the spectral profile of various features. Given the narrow aperture of the two high-resolution modules, cosmic ray hits and spurious features usually plague the spectra. Our pipeline is designed to minimize these effects through various improvements. A super sampled point-spread function was created in order to enable the optimal extraction in addition to the full aperture extraction. The pipeline selects the best extraction method based on the spatial extent of the object. For unresolved sources, the optimal extraction provides a significant improvement in signal-to-noise ratio over a full aperture extraction. We have developed several techniques for optimal extraction, including a differential method that eliminates low-level rogue pixels (even when no dedicated background observation was performed). The updated CASSIS repository now includes all the spectra ever taken by the IRS, with the exception of mapping observations
Spitzer observations of Abell 1763 - II: Constraining the nature of activity in the cluster-feeding filament with VLA and XMM-Newton data
The Abell 1763 superstructure at z=0.23 contains the first galaxy filament to
be directly detected using mid-infrared observations. Our previous work has
shown that the frequency of starbursting galaxies, as characterized by 24{\mu}m
emission is much higher within the filament than at either the center of the
rich galaxy cluster, or the field surrounding the system. New VLA and
XMM-Newton data are presented here. We use the radio and X-ray data to examine
the fraction and location of active galaxies, both active galactic nuclei (AGN)
and starbursts. The radio far-infrared correlation, X-ray point source
location, IRAC colors, and quasar positions are all used to gain an
understanding of the presence of dominant AGN. We find very few MIPS-selected
galaxies that are clearly dominated by AGN activity. Most radio selected
members within the filament are starbursts. Within the supercluster, 3 of 8
spectroscopic members detected both in the radio and in the mid-infrared are
radio-bright AGN. They are found at or near the core of Abell 1763. The five
starbursts are located further along the filament. We calculate the physical
properties of the known wide angle tail (WAT) source which is the brightest
cluster galaxy (BCG) of Abell 1763. A second double lobe source is found along
the filament well outside of the virial radius of either cluster. The velocity
offset of the WAT from the X-ray centroid, and the bend of the WAT in the
intracluster medium (ICM) are both consistent with ram pressure stripping,
indicative of streaming motions along the direction of the filament. We
consider this as further evidence of the cluster-feeding nature of the galaxy
filament.Comment: 26 pages, 13 figures AJ, accepte
Forbush decrease observed by SEVAN particle detector network on November 4, 2021
On November 3-4 2021, an interplanetary coronal mass injection (ICME) hits
the magnetosphere, sparking a strong G3-class geomagnetic storm and auroras as
far south as California and New Mexico. All detectors of the SEVAN network
registered a Forbush decrease (FD) of 5-10 percentdeep in 1 minute time series
of count rates. We present the results of a comparison of Fd registered on
mountain altitudes on Aragats (Armenia), Lomnicky Stit (Slovakia), Musala
(Bulgaria), and at sea level DESY (Hamburg, Germany), and in Mileshovka,
Czechia. We present as well purity and barometric coefficients of different
coincidences of SEVAN detector layers on Aragats. We demonstrate disturbances
of the near-surface electric (NSEF) and geomagnetic fields at the arrival of
the ICME on Earth
Correlation Effects in Nuclear Transparency
The Glauber approximation is used to calculate the contribution of nucleon
correlations in high-energy reactions. When the excitation energy of
the residual nucleus is small, the increase of the nuclear transparency due to
correlations between the struck nucleon and the other nucleons is mostly
compensated by a decrease of the transparency due to the correlations between
non detected nucleons. We derive Glauber model predictions for nuclear
transparency for the differential cross section when nuclear shell level
excitations are measured. The role of correlations in color transparency is
briefly discussed.Comment: 24 pages revtex, 4 uuencoded PostScript Figures as separate fil
ФАЗОВЫЕ ПРЕВРАЩЕНИЯ ПРИРОДНЫХ ЦЕОЛИТОВ ПРИ КИСЛОТНОЙ И ЩЕЛОЧНОЙ ОБРАБОТКАХ
The change of zeolite properties of the ‘Noyemberyanskoe’ deposit (Armenia) after their processing with alkaline and acidic solutions (16 mol/dm3 ) has been studied by Xray diffraction and dip pycnometry. It has been established that chemical composition and specific total pore volume of clinoptilolite were changed, and also new phases, such as sodalite, gismondine and fillipsite, were formed at sodium hydroxide concentration of ≥ 2 mol/dm3 . It has been found that increasing the hydrochloric acid concentration up to ≈ 6 mol/dm3 leads to size and form change of clinoptilolite sorption channels, and further increase causes its destruction. The method of lowtemperature nitrogen adsorptiondesorption proved the presence of mesoporous constituent in a clinoptilolite rock.Методами дифракции рентгеновских лучей и жидкостной пикнометрии изучено изменение свойств цеолитов Ноемберянского месторождения (Армения) после их обработки щелочными и кислотными растворами (1–6 моль/л). Установлено, что при концентрациях натрия гидроксида ≥ 2 моль/л изменяются химический состав и удельный суммарный объем пор клиноптилолита, а также образуются новые фазы, такие как содалит, жисмондин и филлипсит. Выявлено, что увеличение концентрации соляной кислоты до ≈ 6 моль/л приводит к изменению размеров и форм сорбционных каналов клиноптилолита, а свыше этих значений – к его разрушению. Методом низкотемпературной адсорбции–десорбции азота доказано наличие мезопористой составляющей в образцах клиноптилолитовой породы
Identifying Luminous AGN in Deep Surveys: Revised IRAC Selection Criteria
Spitzer IRAC selection is a powerful tool for identifying luminous AGN. For
deep IRAC data, however, the AGN selection wedges currently in use are heavily
contaminated by star-forming galaxies, especially at high redshift. Using the
large samples of luminous AGN and high-redshift star-forming galaxies in
COSMOS, we redefine the AGN selection criteria for use in deep IRAC surveys.
The new IRAC criteria are designed to be both highly complete and reliable, and
incorporate the best aspects of the current AGN selection wedges and of
infrared power-law selection while excluding high redshift star-forming
galaxies selected via the BzK, DRG, LBG, and SMG criteria. At QSO-luminosities
of log L(2-10 keV) (ergs/s) > 44, the new IRAC criteria recover 75% of the hard
X-ray and IRAC-detected XMM-COSMOS sample, yet only 38% of the IRAC AGN
candidates have X-ray counterparts, a fraction that rises to 52% in regions
with Chandra exposures of 50-160 ks. X-ray stacking of the individually X-ray
non-detected AGN candidates leads to a hard X-ray signal indicative of heavily
obscured to mildly Compton-thick obscuration (log N_H (cm^-2) = 23.5 +/- 0.4).
While IRAC selection recovers a substantial fraction of luminous unobscured and
obscured AGN, it is incomplete to low-luminosity and host-dominated AGN.Comment: 22 pages, 15 figures, accepted for publication in ApJ, full
resolution version available at http://www.stsci.edu/~donley/iragn_paper
PERMANENT MAGNET QUADRUPOLE FOR THE 1-ST TANK OF LINAC-4 *
Abstract A rare-earth (REPM) ∅60 mm diameter, 45 mm long quadrupole for the LINAC-4 focusing channel with an integrated gradient of 2.3 T is described. Thin side washers are used for tuning the quad into specified gradient integral with ±0.5 % accuracy. The single washer contribution calculations are discussed. A method for limiting to 30 μm the magnetic axis offset in the REPM quad is discussed to exclude its compensation by the outer diameter machining before inserting into the drift tube. Nonlinearity of the field is less than 1 % in the reference range of 75 % of beam aperture at the central crosssection near the quad axis. The angular quadrupole arrangement in the drift tube will be provided by machining the main groove on the quad surface in the median plane with 1 mrad accuracy. Calculations of the longitudinal gradient distribution between two neighbour quadrupoles showed that some percents should be added to the nominal gradient in the beginning of the LINAC-4 focusing channel because of partial field compensation
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