Showing papers by "Armenian National Academy of Sciences published in 2011"
TL;DR: Investigation of the mechanisms involved suggests that attainment of a maximal size modulates lifespan, and cumulative results revealed that life expectancy is size-dependent, and that the rate at which cells age is determined in large part by the amount of cell growth per generation.
Abstract: Yeast cells, like mammalian cells, enlarge steadily as they age Unabated cell growth can promote cellular senescence; however, the significance of the relationship between size and cellular lifespan is not well understood Herein, we report a genetic link between cell size, growth rate and lifespan Mutations that increase cell size concomitantly increase growth rate and decrease lifespan As a result, large cells grow, divide and age dramatically faster than small cells Conversely, small cell mutants age slowly and are long-lived Investigation of the mechanisms involved suggests that attainment of a maximal size modulates lifespan Indeed, cumulative results revealed that life expectancy is size-dependent, and that the rate at which cells age is determined in large part by the amount of cell growth per generation
131 citations
TL;DR: In this paper, a more sensitive event-by-event method consisting of a likelihood fit is applied to PKS 2155-304 flare data of MJD 52944 (July 28, 2006) as used in the previous publication.
118 citations
TL;DR: The Sculptor and Carina Dwarf spheroidal galaxies were observed with the H.E.L.S. Cherenkov telescope array between January 2008 and December 2009 as discussed by the authors.
113 citations
TL;DR: In this paper, the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with the unidentified TeV source HESS J1731-347 has motivated further observations of the source with the High Energy Stereoscopic System (H.E.S.) Cherenkov telescope array to test a possible association of the gamma-ray emission with the SNR.
Abstract: The recent discovery of the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with the unidentified TeV source HESS J1731-347 has motivated further observations of the source with the High Energy Stereoscopic System (H.E.S.S.) Cherenkov telescope array to test a possible association of the gamma-ray emission with the SNR. With a total of 59 hours of observation, representing about four times the initial exposure available in the discovery paper of HESS J1731-347, the gamma-ray morphology is investigated and compared with the radio morphology. An estimate of the distance is derived by comparing the interstellar absorption derived from X-rays and the one obtained from 12CO and HI observations. The deeper gamma-ray observation of the source has revealed a large shell-type structure with similar position and extension (r~0.25{\deg}) as the radio SNR, thus confirming their association. By accounting for the H.E.S.S. angular resolution and projection effects within a simple shell model, the radial profile is compatible with a thin, spatially unresolved, rim. Together with RX J1713.7-3946, RX J0852.0-4622 and SN 1006, HESS J1731-347 is now the fourth SNR with a significant shell morphology at TeV energies. The derived lower limit on the distance of the SNR of 3.2 kpc is used together with radio and X-ray data to discuss the possible origin of the gamma-ray emission, either via inverse Compton scattering of electrons or the decay of neutral pions resulting from proton-proton interaction.
94 citations
TL;DR: Evidence is provided from direct experimentation and mathematical modeling that the synexpressed feedback inhibitors BAMBI, SMAD6, and SMAD7 expand the dynamic BMP signaling range essential for proper embryonic patterning and reduce interindividual phenotypic and molecular variability in Xenopus embryos.
Abstract: What makes embryogenesis a robust and canalized process is an important question in developmental biology. A bone morphogenetic protein (BMP) morphogen gradient plays a key role in embryonic development, and we are beginning to understand how the self-regulating properties of its signaling circuitry ensure robust embryonic patterning. An unexplored question is why the BMP signaling circuit is organized as a modular synexpression group, with a prevalence of feedback inhibitors. Here, we provide evidence from direct experimentation and mathematical modeling that the synexpressed feedback inhibitors BAMBI, SMAD6, and SMAD7 (i) expand the dynamic BMP signaling range essential for proper embryonic patterning and (ii) reduce interindividual phenotypic and molecular variability in Xenopus embryos. Thereby, negative feedback linearizes signaling responses and confers robust patterning, thus promoting canalized development. The presence of negative feedback inhibitors in other growth factor synexpression groups suggests that these properties may constitute a general principle.
72 citations
01 Jan 2011
TL;DR: In this article, a new very high-energy (VHE; E>100 GeV) γ-ray source, HESSJ1026-582, was discovered with a statistical significance of 7σ.
Abstract: Aims. Previous observations with the H.E.S.S. telescope array revealed the existence of extended very-high-energy (VHE; E>100 GeV) {\gamma}-ray emission, HESS J1023-575, coincident with the young stellar cluster Westerlund 2. At the time of discovery, the origin of the observed emission was not unambiguously identified, and follow-up observations have been performed to further investigate the nature of this {\gamma}-ray source. Methods. The Carina region towards the open cluster Westerlund 2 has been re-observed, increasing the total exposure to 45.9 h. The combined dataset includes 33 h of new data and now permits a search for energy-dependent morphology and detailed spectroscopy. Results. A new, hard spectrum VHE {\gamma}-ray source, HESSJ1026-582, was discovered with a statistical significance of 7{\sigma}. It is positionally coincident with the Fermi LAT pulsar PSR J1028-5819. The positional coincidence and radio/{\gamma}-ray characteristics of the LAT pulsar favors a scenario where the TeV emission originates from a pulsar wind nebula. The nature of HESS J1023-575 is discussed in light of the deep H.E.S.S. observations and recent multi-wavelength discoveries, including the Fermi LAT pulsar PSRJ1022-5746 and giant molecular clouds in the region. Despite the improved VHE dataset, a clear identification of the object responsible for the VHE emission from HESS J1023-575 is not yet possible, and contribution from the nearby high-energy pulsar and/or the open cluster remains a possibility.
64 citations
TL;DR: In this paper, a new point-like source, HESS J1943+213 located in the Galactic plane, was detected at the significance level of 7.9 \sigma (post-trials) at RA(J2000)=19h 43m 55s +- 1s + - 1s (stat) + 1s+1s (sys), DEC(J 2000) = +21deg 18' 8" +- 17" (stat), +- 20" (sys).
Abstract: We report on a newly detected point-like source, HESS J1943+213 located in the Galactic plane. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts. HESS J1943+213 is detected at the significance level of 7.9 \sigma (post-trials) at RA(J2000)=19h 43m 55s +- 1s (stat) +- 1s (sys), DEC(J2000) = +21deg 18' 8" +- 17" (stat) +- 20" (sys). The source has a soft spectrum with photon index Gamma = 3.1 +- 0.3 (stat) +- 0.2 (sys) and a flux above 470 GeV of 1.3 +- 0.2 (stat) +- 0.3 (sys) x 10^{-12} cm^{-2} s^{-1}. There is no Fermi/LAT counterpart down to a flux limit of 6 x 10^{-9} cm^{-2} s^{-1} in the 0.1-100 GeV energy range (95% confidence upper limit calculated for an assumed power-law model with a photon index Gamma=2.0). The data from radio to VHE gamma-rays do not show any significant variability. We combine new H.E.S.S., Fermi/LAT and Nancay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength observations of IGR J19443+2117 and discuss the likely source associations as well as the interpretation as an active galactic nucleus, a gamma-ray binary or a pulsar wind nebula. The lack of a massive stellar counterpart disfavors the binary hypothesis, while the soft VHE spectrum would be very unusual in case of a pulsar wind nebula. In addition, the distance estimates for Galactic counterparts places them outside of the Milky Way. All available observations favor an interpretation as an extreme, high-frequency peaked BL Lac object with a redshift z>0.14. This would be the first time a blazar is detected serendipitously from ground-based VHE observations, and the first VHE AGN detected in the Galactic Plane.
45 citations
TL;DR: The HESS very-high-energy (VHE, E > 0.1 TeV) gamma-ray telescope system has discovered a new source, HESS J1747-248, which is located in the close vicinity of the Galactic globular cluster Terzan 5 and extends beyond the HESS point spread function as discussed by the authors.
Abstract: The HESS very-high-energy (VHE, E > 0.1 TeV) gamma-ray telescope system has discovered a new source, HESS J1747-248. The measured integral flux is (1.2 ± 0.3) × 10 −12 cm −2 s −1 above 440 GeV for a power-law photon spectral index of 2.5 ± 0.3stat ± 0.2sys. The VHE gamma-ray source is located in the close vicinity of the Galactic globular cluster Terzan 5 and extends beyond the HESS point spread function (0.07 ◦ ). The probability of a chance coincidence with Terzan 5 and an unrelated VHE source is quite low (∼10 −4 ). With the largest population of identified millisecond pulsars (msPSRs), a very high core stellar density and the brightest GeV range flux as measured by Fermi-LAT, Terzan 5 stands out among Galactic globular clusters. The properties of the VHE source are briefly discussed in the context of potential emission mechanisms, notably in relation to msPSRs. Interpretation of the available data accommodates several possible origins for this VHE gamma-ray source, although none of them offers a satisfying explanation of its peculiar morphology.
44 citations
01 Sep 2011
TL;DR: In this paper, a very high-energy (VHE; E > 100 GeV) γ-ray sources in the Galaxy are associated with energetic pulsars in the VHE regime.
Abstract: Context Several newly discovered very-high-energy (VHE; E > 100 GeV) γ-ray sources in the Galaxy are thought to be associated with energetic pulsars Among them, middle-aged (>10 4 yr) systems exhibit large centre-filled VHE nebulae, offset from the pulsar position, which result from the complex relationship between the pulsar wind and the surrounding medium, and reflect the past evolution of the pulsar Aims Imaging Atmospheric Cherenkov Telescopes (IACTs) have been successful in revealing extended emission from these sources in the VHE regime Together with radio and X-ray observations, this observational window allows one to probe the energetics and magnetic field inside these large-scale nebulae Methods HESS, with its large field of view, angular resolution of <01 ◦ and unprecedented sensitivity, has been used to discover a large population of such VHE sources In this paper, the HESS data from the continuation of the Galactic Plane Survey (−80 ◦ <�< 60 ◦ , |b| < 3 ◦ ), together with the existing multi-wavelength observations, are used Results A new VHE γ-ray source was discovered at RA (J2000) = 13 h 56 m 00 s , Dec (J2000) = −64 ◦ 30 � 00 �� with a 2 � statistical error in each coordinate, namely HESS J1356−645 The source is extended, with an intrinsic Gaussian width of (020 ± 002) ◦ Its integrated energy flux between 1 and 10 TeV of 8 × 10 −12 erg cm −2 s −1 represents ∼11% of the Crab Nebula flux in the same energy band The energy spectrum between 1 and 20 TeV is well described by a power law dN/dE ∝ E −Γ with photon index Γ= 22 ± 02stat ± 02sys The inspection of archival radio images at three frequencies and the analysis of X-ray data from ROSAT/PSPC and XMM-Newton/MOS reveal the presence of faint non-thermal diffuse emission coincident with HESS J1356−645 Conclusions HESS J1356−645 is most likely associated with the young and energetic pulsar PSR J1357−6429 (d = 24 kpc, τc = 73 kyr and u E = 31 × 10 36 erg s −1 ), located at a projected distance of ∼5 pc from the centroid of the VHE emission HESS J1356−645 and its radio and X-ray counterparts would thus represent the nebula resulting from the past history of the PSR J1357−6429 wind In a simple one-zone model,
42 citations
TL;DR: In this paper, the dark matter content of the globular clusters NGC 6388 and M 15 is modelled taking into account the astrophysical processes that can be expected to influence the darkmatter distribution during the evolution of the Globular cluster.
Abstract: Observations of the globular clusters NGC 6388 and M 15 were carried out by the H.E.S.S. array of Cherenkov telescopes for a live time of 27.2 and 15.2 hours respectively. No gamma-ray signal is found at the nominal target position of NGC 6388 and M 15. In the primordial formation scenario, globular clusters are formed in a dark matter halo and dark matter could still be present in the baryon-dominated environment of globular clusters. This opens the possibility of observing a dark matter self-annihilation signal. The dark matter content of the globular clusters NGC 6388 and M 15 is modelled taking into account the astrophysical processes that can be expected to influence the dark matter distribution during the evolution of the globular cluster: the adiabatic contraction of dark matter by baryons, the adiabatic growth of a black hole in the dark matter halo and the kinetic heating of dark matter by stars. 95% confidence level exclusion limits on the dark matter particle velocity-weighted annihilation cross section are derived for these dark matter haloes. In the TeV range, the limits on the velocity-weighted annihilation cross section are derived at the 10-25 cm3 s-1 level and a few 10-24 cm3 s-1 for NGC 6388 and M 15 respectively.
42 citations
TL;DR: In conclusion, this single-cohort study nominates the BDNF 66Met allele as a risk factor for schizophrenia in an Armenian population and must be confirmed in other Armenian cohorts.
TL;DR: In this paper, the authors presented fission track (FT) data from the northern hinterland of the Tabriz Basin (Upper Red Formation) and from the Fish Beds, which support previous age assumptions for the Upper Red Formation, but, together with the new biostratigraphic data, point to an older stratigraphic age for the Lignite and fish Beds than previously thought.
TL;DR: In this paper, a cascaded parametric down-conversion (PDC) in superlattice structures of nonlinear and linear segments was proposed to realize controllable sources generating joint multiphoton states, particularly photon triplet with arbitrary spectral characteristics.
Abstract: It has been a longstanding goal in quantum optics to realize controllable sources generating joint multiphoton states, particularly photon triplet with arbitrary spectral characteristics. We demonstrate that such sources can be realized via cascaded parametric down-conversion (PDC) in superlattice structures of nonlinear and linear segments. We consider a scheme that involves two parametric processes---${\ensuremath{\omega}}_{0}\ensuremath{\rightarrow}{\ensuremath{\omega}}_{1}+{\ensuremath{\omega}}_{2}$, ${\ensuremath{\omega}}_{2}\ensuremath{\rightarrow}{\ensuremath{\omega}}_{1}+{\ensuremath{\omega}}_{1}$ under pulsed pump---and investigate the spontaneous creation of a photon triplet as well as the generation of high-intensity mode in intracavity three-photon splitting. We show the preparation of Greenberger-Horne-Zeilinger polarization-entangled states in cascaded type-II and type-I PDC in the framework of considering the dual-grid structure that involves two periodically poled crystals. We demonstrate the method of compensation of the dispersive effects in nonlinear segments by appropriately chosen linear dispersive segments of superlattice for preparation of the heralded joint states of two polarized photons. In the case of intracavity three-photon splitting, we concentrate on the investigation of photon-number distributions, third-order photon-number correlation function, as well as the Wigner functions. These quantities are observed both for short interaction time intervals and the over-transient regime, when dissipative effects are essential.
TL;DR: In this paper, the authors analyzed palaeoenvironmental, faunal, and archaeological data gathered during 2006-2009 excavations of the Palaeolithic cave site of Hovk-1, Armenia, in order to address whether human presence in this cave correlates with episodes of mild climate and certain environmental and ecological conditions that were favorable to huminin occupation in such a region.
01 Sep 2011
TL;DR: The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV γ-ray (H.E.S.), GeV − γ −ray (Fermi/LAT), X − ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands.
Abstract: The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV γ-ray (H.E.S.S.), GeV γ-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E > 100 GeV) spectrum measured with H.E.S.S.
TL;DR: The MD simulations indicate a more rigid and ordered surfactant film due to the formation of a polyelectrolyte palisade layer in full agreement with the experimental findings, e.g. the viscosity increase and shift of the percolation boundary.
TL;DR: The results obtained suggest that C1QB gene may be considered as a relevant candidate gene for susceptibility to schizophrenia, and its rs291982*G minor allele might represent a risk factor for schizophrenia at least in Armenian population.
Abstract: Schizophrenia is a complex, multifactorial psychiatric disorder. Our previous findings indicated that altered functional activity of the complement system, a major mediator of the immune response, is implicated in the pathogenesis of schizophrenia. In order to explore whether these alterations are genetically determined or not, in the present study we evaluated the possible association of complement C1Q component gene variants with susceptibility to schizophrenia in Armenian population, focusing on four frequent single nucleotide polymorphisms (SNPs) of C1QA and C1QB genes. In the present study four SNPs of the complement C1Q component genes (C1QA: rs292001, C1QB rs291982, rs631090, rs913243) were investigated in schizophrenia-affected and healthy subjects. Unrelated Caucasian individuals of Armenian nationality, 225 schizophrenic patients and the same number of age- and sex-matched healthy subjects, were genotyped. Genotyping was performed using polymerase chain reaction with sequence-specific primers (PCR-SSP) and quantitative real-time (qRT) PCR methods. While there was no association between C1QA rs292001, C1QB rs913243 and rs631090 genetic variants and schizophrenia, the C1QB rs291982*G minor allele was significantly overrepresented in schizophrenic patients (G allele frequency 58%) when compared to healthy subjects (46%, OR = 1.64, p
corr = 0.0008). Importantly, the susceptibility for schizophrenia was particularly associated with C1QB rs291982 GG genotype (OR = 2.5, p
corrected = 9.6E-5). The results obtained suggest that C1QB gene may be considered as a relevant candidate gene for susceptibility to schizophrenia, and its rs291982*G minor allele might represent a risk factor for schizophrenia at least in Armenian population. Replication in other centers/populations is necessary to verify this conclusion.
TL;DR: This study for the first time indicated that schizophrenia is associated with the increased CR1 expression and C1q-CIC level and further studies in other ethnic groups are needed to replicate these findings.
Abstract: Whereas the complement system alterations contribute to schizophrenia, complement receptors and regulators are little studied. We investigated complement receptor type 1 (CR1) expression on blood cells, the levels of circulating immune complexes (CIC) containing ligands of CR1, C1q complement protein and fragments of C3 complement protein (C1q-CIC, C3d-CIC), and CR1 C5507G functional polymorphism in schizophrenia patients and controls. We found an increased C1q-CIC level and CR1 expression on blood cells, elevated number of CR1 positive erythrocytes and reduced number of CR1 positive lymphocytes and monocytes in patients compared to controls. No difference in the levels of C3d-CIC between groups was observed. Higher CR1 expression on erythrocytes in CC genotype versus CG+GG for both groups was detected, whereas no difference was observed for other cell populations. Our results indicated that schizophrenia is associated with the increased CR1 expression and C1q-CIC level. Our study for the first time indicated that schizophrenia is associated with the increased CR1 expression and C1q-CIC level. Further studies in other ethnic groups are needed to replicate these findings.
TL;DR: A detailed review of trepanation and cranial deformation in ancient Armenia is presented in this paper, which is based on human remains uncovered at sites in Beniamin, Black Fortress I, Shirakavan, Karmrakar and Vardbakh.
Abstract: Trepanation and artificial cranial deformations in ancient Armenia The purpose of the paper is to review surgical and ritual practices on people living on the Shirak Plateau (Armenia) during the Late Antiquity period (1st century BC - 3rd century AD) and is based on human remains uncovered at sites in Beniamin, Black Fortress I, Shirakavan, Karmrakar and Vardbakh. The basic demographic data for these cases, including the age and sex of the skeleton, the precise location of the trepanation, the form of the trepanation and instruments used, and the presence of any associated pathologies, injuries, diseases, or developmental deformities on the skeleton, are specified. The phenomenon of artificial skull and teeth modifications identified at ancient burials sites in Armenia clearly points to the emergence of social complexity and class differentiation, and hence the need for social distinction, which in this case was accomplished through the use of body markings. A compilation of case reports and information on trepanation and deformation is essential for a bioarcheological study of the procedure. Chirurgia jest jedną z najstarszych dziedzin wiedzy medycznej. W praktyce antropologicznej do trepanacji zalicza się otwory wykonane w czaszce zarówno w celach rytualnych, jak i leczniczych. Takim leczniczym zabiegiem są trepanacje dla usunięcia odłamków kostnych powstałych po urazach kości czaszki, a także przy uporczywych bólach głowy, epilepsji i innych chorobach. Obserwacje morfologii czaszek stwarzają również możliwość zbadania dwóch rodzajów sztucznych deformacji głowy: puszki mózgowej i zębów. Celowe działanie na mózgoczaszkę z zamiarem zmienienia kształtu głowy stwierdzano w wielu grupach etnicznych, różniących się geograficznie i chronologicznie. Motywy zamierzonej deformacji głowy mogą być bardzo różne: podkreślenie wyróżnionej pozycji społecznej i odróżnienie od obcoplemieńców, poprawienie \"niewłaściwego\" kształtu czaszki i uzyskanie \"pięknych\" proporcji głowy wymaganych lokalną normą estetyczną, itp. Motywem deformacji zębów także może być uleganie normie estetycznej lub wskazywanie statusu społecznego danego człowieka. Podstawowym materiałem niniejszych badań były znaleziska kraniologiczne ekspedycji z terenu równiny Szirak w Armenii (ryc. 1). Analizowany materiał składa się z 5 serii: Beniamin, Wardbach, Szirakawan, Karmrakar i Czarna Twierdza I (patrz tab. 1-2). Wśród zbadanych materiałów znalazły się dwie czaszki z epoki późno antycznej ze śladami trepanacji (ryc. 2B, 2C i 3). Trepanacje wykonano metodą wiercenia. W obu przypadkach śródkoście było zasklepione na całym brzegu otworu, co oznacza, że trepanowani żyli po operacji. Na równinie Szirak odkryto nieznane wcześniej czaszki z epoki antycznej ze sztucznymi deformacjami. Wykonywanie celowej pierścieniowej deformacji głowy stosowała ludność ze stanowisk Veniamin, Wardbach, Szirakawan i Karmrakar. Na cmentarzysku w Beniamin (u 4 dorosłych i 26 dzieci) występują deformacje pierścieniowe czołowo-potyliczne dwóch typów: o formie zbliżonej do stożka (ryc. 5) i formie wieżowej (ryc. 4). Pierścieniowa deformacja występuje także u osobnika z Karmrakar (ryc. 6). Wyraźne ślady celowej deformacji pierścieniowej (ryc. 7) i punktowej (ryc. 8) stwierdzono także u osobników z antycznego cmentarzyska Wardbach. Warto dodać, że na terenach Wyżyny Armeńskiej spotyka się znaleziska rzeźb - kamiennych idoli zwieńczonych kobiecą lub męską głową (ryc. 10). U jednych przybranie głowy ma formę stożkowatą, u innych - ściętego stożka. U przedstawicieli starożytnej ludności Armenii z cmentarzyska Beniamin stwierdzono ponadto sztuczne deformacje zębów - u trzech osobników (ryc. 11) przednie zęby były spiłowane. Wydaje się, że zwyczaj sztucznego deformowania głowy i zębów wiązał się z rosnącą złożonością społeczeństwa i wynikającą stąd potrzebą znakowania różnic społecznych.
TL;DR: In this paper, the composition method of constructing families of irreducible polynomials over finite fields is studied, and the composition of polynomial families is described.
Abstract: The paper is devoted to the composition method of constructing families of irreducible polynomials over finite fields.
TL;DR: In this article, the authors measured the level of hydroxy, branched, cyclopropyl and unsaturated fatty acids, aldehydes, and phenyl derivatives in blood of patients with a hereditary autoinflammatory disorder, familial Mediterranean fever (FMF), and in patients with peptic ulceration (PU) resulting from Helicobacter pylori infection.
Abstract: The human gastrointestinal tract is inhabited by a diverse and dense symbiotic microbiota, the composition of which is the result of host-microbe co-evolution and co-adaptation. This tight integration creates intense crosstalk and signalling between the host and microbiota at the cellular and metabolic levels. In many genetic or infectious diseases the balance between host and microbiota may be compromised resulting in erroneous communication. Consequently, the composition of the human metabolome, which includes the gut metabolome, may be different in health and disease states in terms of microbial products and metabolites entering systemic circulation. To test this hypothesis, we measured the level of hydroxy, branched, cyclopropyl and unsaturated fatty acids, aldehydes, and phenyl derivatives in blood of patients with a hereditary autoinflammatory disorder, familial Mediterranean fever (FMF), and in patients with peptic ulceration (PU) resulting from Helicobacter pylori infection. Discriminant function analysis of a data matrix consisting of 94 cases as statistical units (37 FMF patients, 14 PU patients, and 43 healthy controls) and the concentration of 35 microbial products in the blood as statistical variables revealed a high accuracy of the proposed model (all cases were correctly classified). This suggests that the profile of microbial products and metabolites in the human metabolome is specific for a given disease and may potentially serve as a biomarker for disease.
TL;DR: In this article, a very high-energy (VHE; E > 100 GeV) gamma-ray source was detected with a statistical significance of 7 sigma, although no significant point-like emission was detected at the position of the energetic pulsar itself.
Abstract: The gamma-ray pulsar PSR B1706-44 and the adjacent supernova remnant (SNR) candidate G343.1-2.3 were observed by H.E.S.S. during a dedicated observation campaign in 2007. As a result of this observation campaign, a new source of very-high-energy (VHE; E > 100 GeV) gamma-ray emission, HESS J1708-443, was detected with a statistical significance of 7 sigma, although no significant point-like emission was detected at the position of the energetic pulsar itself. In this paper, the morphological and spectral analyses of the newly-discovered TeV source are presented. The centroid of HESS J1708-443 is considerably offset from the pulsar and located near the apparent center of the SNR, at RA(J2000) = 17h08m11s +/- 17s and Dec(J2000) = -44d20' +/- 4'. The source is found to be significantly more extended than the H.E.S.S. point spread function (~0.1 deg), with an intrinsic Gaussian width of 0.29 deg +/- 0.04 deg. Its integral flux between 1 and 10 TeV is ~ 3.8 x 10^-12 ph cm^-2 s^-1, equivalent to 17% of the Crab Nebula flux in the same energy range. The measured energy spectrum is well-fit by a power law with a relatively hard photon index Gamma = 2.0 +/- 0.1 (stat) +/- 0.2 (sys). Additional multi-wavelength data, including 330 MHz VLA observations, were used to investigate the VHE gamma-ray source's possible associations with the pulsar wind nebula of PSR B1706-44 and/or with the complex radio structure of the partial shell-type SNR G343.1-2.3.
Journal Article•
TL;DR: The assemblages of chondrichthyan microremains from the Famennian of Armenia show great resemblances to those from central iran, particularly, the very rich sample (almost 200 teeth) from the lower Famennians of ertych, which contains a fauna similar to that from the iranian section of hutk as discussed by the authors.
Abstract: The assemblages of chondrichthyan microremains from the Famennian of Armenia show great resemblances to those from central iran. particularly, the very rich sample (almost 200 teeth) from the lower Famennian of ertych contains a fauna similar to that from the iranian section of hutk, and the sample from the upper Famennian of khor Virap has its counterpart in the sample from dalmeh, iran. only one chondrichthyan taxon definitely unknown from iran, Ertychius intermedius gen. et sp. nov., was recorded. The other newly described species, Lissodus lusavorichi sp. nov., was noted earlier from dalmeh, but at that time was left unnamed. it appears that the same type of relatively shallow marine environment predominated in the central and north-western parts of the iranian platform during the Famennian and that in a given time-interval the same type of ichthyofauna was distributed throughout the area. The single lower Tournaisian sample from the sevakavan section yielded a peculiar form of thrinacodont teeth, possibly intermediate between Thrinacodus tranquillus and Th. ferox .
TL;DR: In this paper, the chemistry and phase formation mechanism in the salt-controlled MoO3 + MgO + NaCl thermite reaction was studied, and it was found that the structure of phase formation in the studied system primarily depend on the salt content in the initial mixtures.
Abstract: The present work was undertaken to study the chemistry and phase formation mechanism in the salt-controlled MoO3 + Mg + NaCl thermite reaction. It was found that the structure and phase formation mechanism in the studied system primarily depend on the salt content in the initial mixtures. In salt-poor mixtures, nucleation of product particles takes place in the molten magnesium, whereas under salt-rich conditions, products are mainly formed in molten sodium chloride. Analyses of combustion temperature profiles and product microstructures and thermal analysis of reacting mixtures suggested that the molybdenum oxide reacts with the salt at early stages of the process. The formed intermediate molybdenum oxychloride and sodium molybdate then react with magnesium, yielding Mo, MgO, and NaCl phases. The low value of the activation energy (50 kJ/mol) of the combustion process also suggests that gaseous (liquid) intermediates play an important role in the phase formation mechanism.
TL;DR: This study aimed to further elucidate the molecular mechanisms of antiproliferative action of proline rich polypeptide 1 (PRP-1) cytokine, produced by neurosecretory cells of the hypothalamus to be considered as alternative adjuvant therapy for metastatic chondrosarcoma, which does not respond to chemotherapy or radiation and currently without any effective treatment.
Abstract: This study aimed to further elucidate the molecular mechanisms of antiproliferative action of proline rich polypeptide 1 (PRP-1) cytokine, produced by neurosecretory cells of the hypothalamus to be considered as alternative adjuvant therapy for metastatic chondrosarcoma, which does not respond to chemotherapy or radiation and currently without any effective treatment. Rapid cell proliferation assay of human primary cultures from high grade chondrosarcoma patients biopsies and human chondrosarcoma JJ012 cell line indicated 50 and 80% inhibition in PRP-1 treated samples correspondingly. Videomicroscopy detected that despite the treatment there are still dividing cells, meaning that cells are not in the state of dormancy, rather PRP-1 repressed the cell cycle progression, exhibited cytostatic effect. The mammalian target of rapamycin (mTOR) is an intracellular serine/threonine protein kinase that has a crucial role in a nutrient sensitive signaling pathway that regulates cell growth. Experiments with mTOR pathway after PRP-1 (10 μg/ml) treatment indicated statistically significant 30% inhibition of mTOR activity and its 56% inhibition in immunoprecipitates with PRP-1 concentrations effective for cell proliferation inhibition. Treatment with PRP- caused inhibition of mTOR and downstream target cMyc oncogenic transcription factor sufficient to trigger the cytostatic effect in high grade, but not in low grade chondrosarcomas. The fact that lower concentrations than 10 μg/ml peptide with cytostatic effect did not inhibit mTOR, but inhibited cMyc prompted us to assume that PRP-1 binds to two different receptors facilitating the antiproliferative effect.
TL;DR: In this paper, the autocorrection phenomenon was studied in the context of the so-called Krylov-Gottlieb-Eckhoff (KGE) method.
Abstract: We consider the so-called Krylov-Gottlieb-Eckhoff (KGE) approximation of a function f with a discontinuity at a known point. This approximation is based on certain corrections associated with the jumps in the first q derivatives of f . The approximation of the exact jumps is accomplished by the solution of a system of linear equations. We show that in the regions where the 2-periodic extension of the approximated function is smooth the KGE method with approximate values of the jumps converges faster compared with the case where the exact values are used. This accelerated convergence we call the autocorrection phenomenon that was discovered in the past by numerical experiments. The paper presents a theoretical explanation of the phenomenon with numerical illustrations. Fourier Coefficients, Bernoulli Polynomials, Convergence Acceleration, Autocorrection Phenomenon
TL;DR: In this article, the IR absorption spectra of various amorphous silicas were studied and Si-O bonds with various strengths were formed in siloxane groups, depending on the conditions of the preparation of SiO2.
Abstract: The IR absorption spectra of various amorphous silicas were studied. Depending on the conditions of the preparation of amorphous SiO2, Si-O bonds with various strengths were formed in siloxane groups.
TL;DR: In this article, the authors investigated the solvability of a class of nonlinear integral equations on the semiaxis in a critical case, which possess a noncompact operator of almost Hammerstein type.
Abstract: The paper is devoted to investigation of the solvability of a class of nonlinear integral equations on the semiaxis in a critical case, which possess a noncompact operator of almost Hammerstein type. Under some conditions on the equation kernel, the existence of a bounded, monotone increasing, positive solution is proved. The asymptotic behavior of the solution near infinity is studied.
TL;DR: Whether any evidence for genetic regional partitioning in Armenians exists is addressed by analyzing, for the first time, 15 autosomal short tandem repeat (STR) loci in 404 Armenians from four geographically well-characterized collections that represent distinct communities from across Historical Armenia.
Abstract: The archeology and ethnology of Armenia suggest that this region has acted as a crossroads for human migrations from Europe and the Middle East since at least the Neolithic. Near continual foreign influx has, in turn, led to the supposition that the gene pools of geographically separated Armenian populations may have diverged as differing historical influences potentially left distinct genetic traces in the various regions of the Armenian plateau. In this study, we seek to address whether any evidence for such genetic regional partitioning in Armenians exists by analyzing, for the first time, 15 autosomal short tandem repeat (STR) loci in 404 Armenians from four geographically well-characterized collections (Ararat Valley, Gardman, Sasun, and Lake Van) that represent distinct communities from across Historical Armenia. In addition, to determine whether genetic differences among these four Armenian populations are the result of differential affinities to populations of known historical influence in Armenia, we utilize 27 biogeographically targeted reference populations for phylogenetic and admixture analyses. From these examinations, we find that while close genetic affiliations exist between the two easternmost Armenian groups analyzed, Ararat Valley and Gardman, the remaining two populations display substantial distinctions. In particular, Sasun is distinguished by evidence for genetic contributions from Turkey, while a stronger Balkan component is detected in Lake Van, potentially suggestive of remnant genetic influences from ancient Greek and Phrygian populations in this region.