5,857 research outputs found
Circumbinary disk evolution
We study the evolution of circumbinary disks surrounding classical T Tau stars. High resolution numerical simulations are employed to model a system consisting of a central eccentric binary star within an accretion disk. The disk is assumed to be infinitesimally thin, however a detailed energy balance including viscous heating and radiative cooling is applied. A novel numerical approach using a parallelized Dual-Grid technique on two different coordinate systems has been implemented. Physical parameters of the setup are chosen to model the close systems of DQ Tau and AK Sco, as well as the wider systems of GG Tau and UY Aur. Our main findings are for the tight binaries a substantial flow of material through the disk gap which is accreted onto the central stars in a phase dependent process. We are able to constrain the parameters of the systems by matching both accretion rates and derived spectral energy distributions to observational data where available
ΠΠ΅ΡΠΎΠ΄Ρ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π²ΠΈΠ½ΡΠΎΠ²ΡΡ ΠΊΠ°Π½Π°Π²ΠΎΠΊ Π±Π°ΡΠ°Π±Π°Π½Π° ΡΡΠ°Π½ΡΠΏΠΎΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄ΡΠ»Ρ Π³Π΅ΠΎΡ ΠΎΠ΄Π°
Cadaveric Renal transplantation with Cyclosporine: Experiences in 148 patients at a single institution.
Electronic structure of intermetallics based on a rare earth element and a transition or noble metal
The results of ab initio study of resonant surface states genesis in the vicinity of Ξ point for GdRh[2]Si[2] are presented in this work. Our electronic band structure calculations have shown that the resonant surface states are already formed in three atomic layer slab Si-Rh-Si. The states localization within three layer slab causes its resonant nature and presence of these states on Si- and Gd- termination surfaces
Π Π°Π·ΡΠ°Π±ΠΎΡΠΊΠ° ΡΠΏΠΎΡΠΎΠ±ΠΎΠ², Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² ΠΈ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΠΈ ΠΈΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΏΠ°ΠΊΠ΅ΡΠ½ΡΡ ΠΈΠ»ΠΈ Π½Π΅Π·Π°Π²ΠΈΡΠΈΠΌΡΡ ΠΎΡΠΈΠ±ΠΎΠΊ ΠΏΡΠΈ ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠ΅ Π΄Π°Π½Π½ΡΡ ΠΏΠΎ ΠΊΠ°Π½Π°Π»Π°ΠΌ ΡΠ²ΡΠ·ΠΈ
ΠΠ°ΡΡΠΎΡΡΠ°Ρ Π½Π°ΡΡΠ½ΠΎ-ΠΊΠ²Π°Π»ΠΈΡΠΈΠΊΠ°ΡΠΈΠΎΠ½Π½Π°Ρ ΡΠ°Π±ΠΎΡΠ° ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π° ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ΅ ΡΠΏΠΎΡΠΎΠ±ΠΎΠ², Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² ΠΈ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΠΈ ΠΈΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΎΡΠΈΠ±ΠΎΠΊ ΠΏΡΠΈ ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠ΅ Π΄Π°Π½Π½ΡΡ
ΠΏΠΎ ΠΊΠ°Π½Π°Π»Π°ΠΌ ΡΠ²ΡΠ·ΠΈ Π΄Π»Ρ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ ΡΠ΅Π»ΠΎΡΡΠ½ΠΎΡΡΠΈ ΠΈ Π½Π°Π΄ΡΠΆΠ½ΠΎΡΡΠΈ ΠΏΠ΅ΡΠ΅Π΄Π°Π²Π°Π΅ΠΌΡΡ
ΠΊΠΎΠΌΠ°Π½Π΄ ΠΈ Π΄Π°Π½Π½ΡΡ
ΠΌΠ΅ΠΆΠ΄Ρ ΡΡΡΡΠΎΠΉΡΡΠ²Π°ΠΌΠΈ Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΠΎ ΡΠ΅Ρ
Π½ΠΈΠΊΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΏΡΠΈ ΡΡΠΈΡΡΠ²Π°Π½ΠΈΠΈ Π΄Π°Π½Π½ΡΡ
ΠΈΠ· Π·Π°ΠΏΠΎΠΌΠΈΠ½Π°ΡΡΠΈΡ
ΡΡΡΡΠΎΠΉΡΡΠ².The present scientific and qualification work is devoted to the development of methods, algorithms and programs for detecting and correcting errors in the transmission of data over communication channels to ensure the integrity and reliability of the transmitted commands and data between computing devices, as well as when reading data from memory devices
Π Π°Π·ΡΠ°Π±ΠΎΡΠΊΠ° ΡΠΎΠ»Π½Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΡΠ΅ΠΊΠ΅ΡΠ° ΠΈ Π°ΠΊΡΠΈΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠ°ΡΠΎΡΠ°
Temozolomide induces apoptosis and senescence in glioma cells cultured as multicellular spheroids
Temozolomide is an alkylating cytostatic drug that finds increasing application in the treatment of melanoma, anaplastic astrocytoma and glioblastoma multiforme. The compound is a prodrug that decomposes spontaneously, independent of an enzymatic activation step. DNA methylation induces futile mismatch repair cycles and depletion of the DNA repair enzyme O6-methylguanine-DNA methyltransferase should then initiate programmed cell death. We show drug-dependent inhibition of tumour growth in a three-dimensional cell culture model of the glioma cell lines U87MG and GaMG. Migrational behaviour of the glioblastoma cells remained unaltered. However, coincubation of tumour spheroids with primary brain aggregates showed reduced tumour cell invasion into brain tissue in the presence of temozolomide. This was not achieved by slowing cellular migration, as temozolomide-treated cells displayed no reduced motility. By transferase-mediated dUTP nick-end labelling (TUNEL) of apoptotic nuclei, we found that the drug was able to induce apoptosis throughout the tumour cell spheroids. Apoptosis was highest in the core region of the spheroids. Repetitive application of sublethal doses of temozolomide to multicellular spheroids resulted in the development of drug resistance in GaMG cells. We suggest that temozolomide is a strong initiator of apoptosis in glioblastoma tumour cells in a spheroid cell culture system, when cells are already in a stressful environment
Huygens' Principle for the Klein-Gordon equation in the de Sitter spacetime
In this article we prove that the Klein-Gordon equation in the de Sitter
spacetime obeys the Huygens' principle only if the physical mass of the
scalar field and the dimension of the spatial variable are tied by
the equation . Moreover, we define the incomplete Huygens'
principle, which is the Huygens' principle restricted to the vanishing second
initial datum, and then reveal that the massless scalar field in the de Sitter
spacetime obeys the incomplete Huygens' principle and does not obey the
Huygens' principle, for the dimensions , only. Thus, in the de Sitter
spacetime the existence of two different scalar fields (in fact, with m=0 and
), which obey incomplete Huygens' principle, is equivalent to
the condition (in fact, the spatial dimension of the physical world). For
these two values of the mass are the endpoints of the so-called in
quantum field theory the Higuchi bound. The value of the
physical mass allows us also to obtain complete asymptotic expansion of the
solution for the large time. Keywords: Huygens' Principle; Klein-Gordon
Equation; de Sitter spacetime; Higuchi Boun
ΠΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ²Π°ΡΠ½ΠΎΠ³ΠΎ ΡΠ²Π° Π² ΠΈΠ·Π΄Π΅Π»ΠΈΡΡ ΠΈΠ· ΡΠΈΡΠ°Π½ΠΎΠ²ΠΎΠ³ΠΎ ΡΠΏΠ»Π°Π²Π° Ti-6Al-4V, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ Π°Π΄Π΄ΠΈΡΠΈΠ²Π½ΡΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ
Π Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΠ΅ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΡΡ ΡΡΠ°Π²Π½ΠΈΡΠ΅Π»ΡΠ½ΡΡ
Π°Π½Π°Π»ΠΈΠ· ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΡ ΠΈ ΠΌΠΈΠΊΡΠΎΡΠ²Π΅ΡΠ΄ΠΎΡΡΠΈ ΡΠ²Π°ΡΠ½ΡΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ»ΡΡΠ΅Π²ΠΎΠΉ ΡΠ²Π°ΡΠΊΠΈ (ΠΠΠ‘). Π ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π»ΠΈΡΡ ΠΏΠ»Π°ΡΡΠΈΠ½Ρ, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ ΠΏΡΠΎΠΊΠ°ΡΠΊΠΎΠΉ ΠΈ Π°Π΄Π΄ΠΈΡΠΈΠ²Π½ΡΠΌ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ EBF{3} (electronbeam freeform fabrication - ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎ-Π»ΡΡΠ΅Π²ΠΎΠ΅ ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½ΠΈΠ΅ ΡΠ²ΠΎΠ±ΠΎΠ΄Π½ΠΎΠΉ ΡΠΎΡΠΌΡ). ΠΡΡΠ²Π»Π΅Π½ΠΎ Π°Π½Π°Π»ΠΎΠ³ΠΈΡΠ½ΠΎΠ΅ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΡΠ΅Ρ
ΡΠ²Π°ΡΠΎΡΠ½ΡΡ
Π·ΠΎΠ½ ΠΏΠΎΡΠ»Π΅ ΠΠΠ‘ Π² 3D-Π½Π°ΠΏΠ΅ΡΠ°ΡΠ°Π½Π½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠ°Ρ
. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΠΈΡΡ
ΠΎΠ΄Π½ΠΎΠΉ ΡΡΡΡΠΊΡΡΡΡ Π½Π° ΠΏΡΠΎΡΠ΅ΡΡ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ²Π°ΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΡ. ΠΠ· ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² Π΄ΡΡΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠ»Π΅Π΄ΡΠ΅Ρ, ΡΡΠΎ Π·ΠΎΠ½Π° ΠΏΠ»Π°Π²Π»Π΅Π½ΠΈΡ (FZ) Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΠ΅ΡΡΡ ΠΏΠΎΠ²ΡΡΠ΅Π½Π½ΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠ²Π΅ΡΠ΄ΠΎΡΡΡΡ ΠΎΡΠ½ΠΎΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΠΎΡΠ½ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»Π°. ΠΠ΄Π½Π°ΠΊΠΎ Π² ΡΠ»ΡΡΠ°Π΅ ΠΎΠ±ΡΠ°Π·ΡΠΎΠ², ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ EBF{3}, Ρ
Π°ΡΠ°ΠΊΡΠ΅Ρ ΠΏΠΎΠ²ΡΡΠ΅Π½ΠΈΡ ΠΎΡΠ»ΠΈΡΠ°Π΅ΡΡΡ, ΡΡΠΎ ΡΠ²ΡΠ·Π°Π½ΠΎ Ρ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΡΠΌΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ²Π°ΡΠ½ΠΎΠ³ΠΎ ΡΠ²Π°.Comparing analysis of the microstructure and microhardness has been investigated in electron-beam welded Ti-6Al-4V alloy parts obtained by rolling and additive manufacturing. Electron-beam welding produced three distinct zones (FZ - the fusion zone, HAZ - the heat affected zone, BM - the base metal) in the welded material. The influence of the BM on the structure of welded joint is shown. According to the results of microhardness testing, it follows that in the FZ the microhardness is higher than in the BM. However, for samples obtained by EBF{3}, the nature of the increase is different due to the features of the formed microstructure during welding
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Scaling-Up Access to Family Planning May Improve Linear Growth and Child Development in Low and Middle Income Countries
Background: A large literature has indicated a robust association between birth spacing and child survival, but evidence on the association of birth timing with physical growth in low and middle income countries (LMICs) remains limited. Methods and Results: Data from 153 cross-sectional Demographic and Health Surveys (DHS) across 61 LMICs conducted between 1990 and 2011 were combined to assess the association of birth timing with child stunting (height-for-age z-score <β2). A total of 623,789 children of birth order 1β5 contributed to the maternal age analysis, while the birth spacing dataset consisted of 584,226 children of birth order 2 and higher. Compared to 27β34 year old mothers, maternal age under 18 years was associated with a relative stunting risk of 1.35 (95% CI: 1.29β1.40) for firstborn children, whereas the relative risk was 1.24 (95% CI: 1.19β1.29) for mothers aged 18β19 years. The association of young maternal age with stunting was significantly greater for urban residents and those in the top 50% of household wealth. Birth intervals less than 12 months and 12β23 months had relative risks for stunting of 1.09 (95% CI: 1.06β1.12) and 1.06 (95% CI: 1.05β1.06) as compared to a 24β35 month inter-pregnancy interval, respectively. The strength of both teenage pregnancy and short birth interval associations showed substantial variation across WHO region. We estimate that 8.6% (6.9β10.3%) of stunted cases in the South Asian DHS sample would have been averted by jointly eliminating teen pregnancies and birth intervals less than 24 months, while only 3.6% (1.5β5.7%) of stunting cases would have prevented in the Middle East and North Africa sample. Conclusions: Postponing the age of first birth and increasing inter-pregnancy intervals has the potential to significantly reduce the prevalence of stunting and improve child development in LMICs
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