35 research outputs found
Ising Universality in Three Dimensions: A Monte Carlo Study
We investigate three Ising models on the simple cubic lattice by means of
Monte Carlo methods and finite-size scaling. These models are the spin-1/2
Ising model with nearest-neighbor interactions, a spin-1/2 model with
nearest-neighbor and third-neighbor interactions, and a spin-1 model with
nearest-neighbor interactions. The results are in accurate agreement with the
hypothesis of universality. Analysis of the finite-size scaling behavior
reveals corrections beyond those caused by the leading irrelevant scaling
field. We find that the correction-to-scaling amplitudes are strongly dependent
on the introduction of further-neighbor interactions or a third spin state. In
a spin-1 Ising model, these corrections appear to be very small. This is very
helpful for the determination of the universal constants of the Ising model.
The renormalization exponents of the Ising model are determined as y_t = 1.587
(2), y_h = 2.4815 (15) and y_i = -0.82 (6). The universal ratio Q =
^2/ is equal to 0.6233 (4) for periodic systems with cubic symmetry.
The critical point of the nearest-neighbor spin-1/2 model is K_c=0.2216546
(10).Comment: 25 pages, uuencoded compressed PostScript file (to appear in Journal
of Physics A
Non-LTE line formation for heavy elements in four very metal-poor stars
Stellar parameters and abundances of Na, Mg, Al, K, Ca, Sr, Ba, and Eu are
determined for four very metal-poor stars (-2.66 < [Fe/H] < -2.15) based on
non-LTE line formation and analysis of high-resolution (R ~60000 and 90000)
high signal-to-noise (S/N > 200) observed spectra. A model atom for H I is
presented. An effective temperature was obtained from the Balmer Halpha and
Hbeta line wing fits, the surface gravity from the Hipparcos parallax if
available and the non-LTE ionization balance between Ca I and Ca II. Based on
the hyperfine structure affecting the Ba II resonance line, the fractional
abundance of the odd isotopes of Ba was derived for HD 84937 and HD 122563 from
a requirement that Ba abundances from the resonance line and subordinate lines
of Ba II must be equal. For each star, non-LTE leads to a consistency of Teff
from two Balmer lines and to a higher temperature compared to the LTE case, by
up to 60 K. Non-LTE effects are important in spectroscopic determination of
surface gravity from Ca I/Ca II. For each star with a known trigonometric
gravity, non-LTE abundances from the lines of two ionization stages agree
within the error bars, while a difference in the LTE abundances consists of
0.23 dex to 0.40 dex for different stars. Departures from LTE are found to be
significant for the investigated atoms, and they strongly depend on stellar
parameters. For HD 84937, the Eu/Ba ratio is consistent with the relative solar
system r-process abundances, and the fraction of the odd isotopes of Ba, f_odd,
equals 0.43+-0.14. The latter can serve as a constraint on r-process models.
The lower Eu/Ba ratio and f_odd = 0.22+-0.15 found for HD 122563 suggest that
the s-process or the unknown process has contributed significantly to the Ba
abundance in this star.Comment: accepted for publication in A&A, November 16, 200
A Compiled Catalogue of Spectroscopically Determined Elemental Abundances for Stars with Accurate Parallaxes. I.Magnesium
We present a compiled catalogue of effective temperatures, surface gravities,
iron and magnesium abundances, distances, velocity components, and orbital
elements for stars in the solar neighborhood. The atmospheric parameters and
iron abundances are averages of published values derived from model synthetic
spectra for a total of about 2000 values in 80 publications. Our relative
magnesium abundances were found from 1412 values in 31 publications for 876
dwarfs and subgiants using a three-step iteration averaging procedure, with
weights assigned to each source of data as well as to each individual
determination and taking into account systematic deviations of each scale
relative to the reduced mean scale. The estimated assumed completeness for data
sources containing more than five stars, up to late December 2003, exceeds 90%.
For the vast majority of stars in the catalogue, the spatial velocity
components were derived from modern high-precision astrometric observations,
and their Galactic orbit elements were computed using a three-component model
of the Galaxy, consisting of a disk, a bulge, and a massive extended halo.Comment: Accepted for Astron. Rep. 2005, v.49, No.5, p.405-416, 12 pages, 10
figure
Formation of Galactic Systems in Light of the Magnesium Abundance in Field Stars: The Thick Disk
The space velocities and Galactic orbital elements of stars calculated from
the currently available high-accuracy observations in our summary catalog of
spectroscopic magnesium abundances in dwarfs and subgiants in the solar
neighborhood are used to identify thick-disk objects. The relative magnesium
abundances in thick-disk stars are shown to lie within the range
0.0<[Mg/Fe]<0.5 and to decrease with increasing metallicity starting from
[Fe/H]=-1.0. This is interpreted as evidence for a longer duration of the star
formation process in the thick disk. We have found vertical gradients in
metallicity (grad_Z[Fe/H]=-0.13\pm 0.04 kpc^{-1}) and relative magnesium
abundance (grad_Z [Mg/Fe]=0.06\pm 0.02 kpc^{-1}), which can be present in the
subsystem only in the case of its formation in a slowly collapsing protogalaxy.
The large spread in relative magnesium abundance (-0.3<[Mg/Fe]<0.5) in the
stars of the metal-poor "tail" of the thick disk which constitute 8% of the
subsystem, can be explained in terms of their formation inside isolated
interstellar clouds that interacted weakly with the matter of a single
protogalactic cloud. We have found a statistically significant negative radial
gradient in relative magnesium abundance in the thick disk (grad_R
[Mg/Fe]=-0.03\pm 0.01 kpc^{-1}) instead of the expected positive gradient. The
smaller perigalactic orbital radii and the higher eccentricities for
magnesium-richer stars, which among other stars, are currently located in a
small volume of the Galactic space near the Sun are assumed to be responsible
for the gradient inversion. A similar but statistically less significant
inversion is also observed in the subsystem for the radial metallicity
gradient.Comment: Accepted for 2005, Astronomy Letters, Vol. 31, No. 8, P.515-527; 14
pages, 6 figure
Molecular and cellular basis in prediction of gastric cancer: a multidisciplinary research experience
A self-review of the results of multidisciplinary studies on the development of a predictive system for intestinal type gastric cancer (adenocarcinoma) is present. The authors' studies carried out in 2007-2017 in light of recent concepts of prediction and prevention of gastric cancer are discussed. The predictive model for gastric cancer is proposed. This includes an evaluation of inflammatory cytokine genes nucleotide polymorphisms, aberrant expression of microRNA, detection of tissue patterns of gastric atrophy and intestinal metaplasia (metaplastic atrophy), principles and possibilities of pathomorphological monitoring.Представлен самообзор результатов мультидисциплинарных исследований по разработке предиктивной системы в отношении рака желудка кишечного типа (аденокарциномы). Обсуждаются исследования авторов, выполненные в 2007-2017 годах в аспекте современных концепций предикции и превенции рака желудка. Предложена модель предикции рака желудка, включающая оценку нуклеотидных замен в генах воспалительных цитокинов, аберрантную экспрессию микроРНК, детекцию тканевых паттернов атрофии и метапластической атрофии слизистой оболочки желудка, принципы и возможности патоморфологического мониторинга
THE CBS SPECTRA INVESTIGATION AS METHOD OF THE PN CHEMICAL COMPOSITION ANALYSIS
We report the results of the investigations of chemical composition of close binaries which had gone through the stage of common envelope and which are the remnants of planetary nebular cores. High resolution spectra for different phases of orbital period of V471 Tau were taken by RTT-150 telescope and were investigated by the modified SYNTH-K program. It was found that the spectra show noticeable variability with appearance of emission components depended on the orbital period phase. For chemical composition determination the "solar" oscillator strengths for 700 lines were taken. It was found that the chemical content of V471 Tau is composite one and characterized by excess of ?-process elements in the contrast to small underabundance of iron-peak elements. The estimation of different elements excesses allows to determine their contents in planetary nebular phase
Water soluble vitamin E (TMG) as a radioprotector
1365-1371<span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;
line-height:115%;font-family:" times="" new="" roman","serif";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">Tocopherol monoglucoside (TMG), a water soluble
derivative of vitamin E offers protection against deleterious effects of ionizing radiation, both under <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">in vivo <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">and <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">in vitro <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">conditions, to
biological systems. TMG was found to be a potent antioxidant and an effective
free radical scavenger. It forms <span style="font-size:15.5pt;
mso-bidi-font-size:9.5pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">a <span style="font-size:14.0pt;
mso-bidi-font-size:8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">phenoxy<span style="font-size:14.5pt;
mso-bidi-font-size:8.5pt;line-height:115%;font-family:" arial","sans-serif";="" mso-fareast-font-family:"times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">I <span style="font-size:14.0pt;
mso-bidi-font-size:8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">radical similar to trolox upon reaction with
various one-electron oxidants. TMG protected DNA from radiation-induced strand
breaks. It also protected thymine glycol formation induced by gamma-radiation.
Gamma-radiation-induced loss of viability of EL-tumor cells and peroxidation of
lipids in microsomal and mitochondrial membranes were prevented by TMG. TMG was
nontoxic to mice when administered orally up to <span style="font-size:
14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">7.0 <span style="font-size:14.0pt;
mso-bidi-font-size:8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">g/kg body weight. The LD50 dose of
TMG for ip administration in mice was 1<span style="font-size:14.5pt;
mso-bidi-font-size:8.5pt;line-height:115%;font-family:" arial","sans-serif";="" mso-fareast-font-family:"times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">.15 <span style="font-size:14.0pt;
mso-bidi-font-size:8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">g/kg body wt. In rats, following oral and ip administration
of TMG, the absorption (distribution) half lives were <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">5.8 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">and <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">3.0 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">min respectively and
elimination half lives were <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">6.7 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">and <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">3.1 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">min respectively.
Embryonic mortality resulting from exposure of pregnant mice to ionizing radiation
<span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;
font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">(2 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Gy) was reduced by <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">75% <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">by ip administration
of TMG <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;
line-height:115%;font-family:" times="" new="" roman","serif";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">(0.6 <span style="font-size:14.0pt;mso-bidi-font-size:
8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">g/kg, body wt) prior to irradiation. TMG offered
protection to mice against whole body gamma-radiation-induced lethality and
weight loss. The LD5<span style="font-size:11.0pt;
mso-bidi-font-size:5.0pt;line-height:115%;font-family:" arial","sans-serif";="" mso-fareast-font-family:"times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">0(30)<span style="font-size:11.0pt;
mso-bidi-font-size:5.0pt;line-height:115%;font-family:" arial","sans-serif";="" mso-fareast-font-family:"times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"=""> <span style="font-size:14.0pt;
mso-bidi-font-size:8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">of mice increased from <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">6 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">to <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">6.72 <span style="font-size:14.0pt;mso-bidi-font-size:8.0pt;line-height:115%;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Gy upon post irradiation
administration of a single dose of TMG <span style="font-size:14.5pt;
mso-bidi-font-size:8.5pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">(0.6 <span style="font-size:14.0pt;
mso-bidi-font-size:8.0pt;line-height:115%;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">g/kg, body wt) by ip.</span