877 research outputs found
The NASA/OAST telerobot testbed architecture
Through a phased development such as a laboratory-based research testbed, the NASA/OAST Telerobot Testbed provides an environment for system test and demonstration of the technology which will usefully complement, significantly enhance, or even replace manned space activities. By integrating advanced sensing, robotic manipulation and intelligent control under human-interactive supervision, the Testbed will ultimately demonstrate execution of a variety of generic tasks suggestive of space assembly, maintenance, repair, and telescience. The Testbed system features a hierarchical layered control structure compatible with the incorporation of evolving technologies as they become available. The Testbed system is physically implemented in a computing architecture which allows for ease of integration of these technologies while preserving the flexibility for test of a variety of man-machine modes. The development currently in progress on the functional and implementation architectures of the NASA/OAST Testbed and capabilities planned for the coming years are presented
Radiative decay of rho^0 and phi mesons in a chiral unitary approach
We study the rho^0 and phi decays into pi^+ pi^- gamma, pi^0 pi^0 gamma and
phi into pi^0 eta gamma using a chiral unitary approach to deal with the final
state interaction of the M M system. The final state interaction modifies only
moderately the large momenta tail of the photon spectrum of the rho^0 --> pi^+
pi^- gamma decay. In the case of phi decay the contribution to pi^+ pi^- gamma
and pi^0 pi^0 gamma decay proceeds via kaonic loops and gives a distribution of
pi pi invariant masses in which the f_0(980) resonance shows up with a very
distinct peak. The spectrum found for phi --> pi^0 pi^0 gamma decay agrees with
the recent experimental results obtained at Novosibirsk. The branching ratio
for phi --> pi^0 eta gamma, dominated by the a_0(980), is also in agreement
with recent Novosibirsk results.Comment: 14 pages, 3 figures. Revised version using an antisymmetric tensor
notation for the vector mesons. To appear in Physics Letters
New high order relations between physical observables in perturbative QCD
We exploit the fact that within massless perturbative QCD the same Green's
function determines the hadronic contribution to the decay width and the
moments of the cross section. This allows one to obtain relations
between physical observables in the two processes up to an unprecedented high
order of perturbative QCD. A precision measurement of the decay width
allows one then to predict the first few moments of the spectral density in
annihilations integrated up to with high accuracy.
The proposed tests are in reach of present experimental capabilities.Comment: 7 pages, Latex, no figure
Опыт смешанного обучения основам цифровой электроники ГГУ им. Ф. Скорины
The article considers the practical experience of blended learning of students in the basics of digital electronics based on the use of the instrumental distance learning system DL.GSU.BY developed at the FranciskSkorinaGomelStateUniversity. There are described specialized tools for designing, modeling, debugging, and researching digital electronics devices developed specifically for learning the basics of digital electronics.В статье рассматривается практический опыт смешанного обучения студентов основам цифровой электроники на базе использования инструментальной системы дистанционного обучения DL.GSU.BY, разработанной в ГГУ им. Ф. Скорины. Описываются специализированные средства проектирования, моделирования, отладки и исследования устройств цифровой электроники, разработанные специально для обучения основам цифровой электроники
ОБ ОПЫТЕ СМЕШАННОГО ОБУЧЕНИЯ ОСНОВАМ ПРОГРАММИРОВАНИЯ НА ФАКУЛЬТЕТЕ МАТЕМАТИКИ И ТЕХНОЛОГИЙ ПРОГРАММИРОВАНИЯ ГГУ ИМ. Ф. СКОРИНЫ
The article considers the practical experience of mixed teaching first-year students the programming framework on the use of distance learning tool system DL.GSU.BY developed at the GSU. The main factors of increasing the intensity and quality of the learning process are illustrated: the integration of theory and practice, automated personalized learning, automatic knowledge testing, support and encouragement of independent work, automatic permanent visualization of the score sheet.В статье рассматривается практический опыт смешанного обучения первокурсников основам программирования на базе использования инструментальной системы дистанционного обучения DL.GSU.BY, разработанной в ГГУ им. Ф. Скорины. Иллюстрируются основные факторы повышения интенсивности и качества процесса обучения: интеграция теории и практики, автоматизированное персонализированное обучение, автоматическая проверка знаний, поддержка и поощрение самостоятельной работы, автоматическая перманентная визуализация ведомости оценок
Theory of deuteron stripping. From surface integrals to generalized -matrix approach
There are two main reasons for absence of the practical theory of stripping
to resonance states which could be used by experimental groups: numerical
problem of the convergence of the DWBA matrix element when the full transition
operator is included and it is unclear what spectroscopic information can be
extracted from the analysis of transfer reactions populating the resonance
states. The purpose of this paper is to address both questions. The theory of
the deuteron stripping is developed, which is based on the post continuum
discretized coupled channels (CDCC) formalism going beyond of the DWBA and
surface integral formulation of the reaction theory [A. S. Kadyrov et al., Ann.
Phys. {\bf 324}, 1516 (2009)]. First, the formalism is developed for the DWBA
and then extended to the CDCC formalism, which is ultimate goal of this work.
The CDCC wave function takes into account not only the initial elastic
channel but also its coupling to the deuteron breakup channel
missing in the DWBA. Stripping to both bound states and resonances are
included. The convergence problem for stripping to resonance states is solved
in the post CDCC formalism. The reaction amplitude is parametrized in terms of
the reduced width amplitudes (ANCs), inverse level matrix, boundary condition
and channel radius, that is the same parameters which are used in the
conventional -matrix method. For stripping to resonance states many-level,
one and two-channel cases are considered. The theory provides a consistent tool
to analyze both binary resonant reactions and deuteron stripping in terms of
the same parameters.Comment: 37 page
Experimental study of the decay PHI(1020)--->ETA+GAMMA in multi-photon final state
In the SND experiment at VEPP-2M e^+e^- collider the phi(1020) ---> eta+gamma
---> 3pi^0+gamma decay was studied. The branching ratio B(phi--->eta+gamma) =
(1.246 +- 0.025 +- 0.057)% was measured.Comment: 4 pages, 1 figure, 1 table, Submitted to JETP Let
Running mass of the rho0 meson's implication for the dilepton mass spectrum and the mu+mu-/e+e- branching ratio in the K+ --> pi+l+l- decays
We make an attempt to resolve the discrepancy of the observed e+e- mass
spectrum in the K+ --> pi+e+e- decay with that predicted by meson dominance. To
this end we investigate the properties of the rho0 propagator. We use
dispersion relations to evaluate the running mass squared m_rho^2(t) of the
rho0 resonance without adjustable parameters. To improve the convergence of the
dispersion integral, the momentum dependence of strong vertices is taken from
the flux-tube-breaking model of Kokoski and Isgur. The obtained behavior of
m_rho^2(t) at small momentum squared t makes the K+ --> pi+e+e- form factor
rise faster with increasing than in the original meson-dominance
calculation and more in agreement with the published data. As a consequence,
the meson-dominance prediction of the mu+mu-/e+e- branching ratio changes
slightly, from 0.224 to 0.236. We do not see any possibility to accommodate
into the meson-dominance approach an even steeper e+e- spectrum, indicated by
the preliminary data of the E865 collaboration at BNL AGS.Comment: 13 pages, RevTeX, epsf.sty, 4 embedded figure
Hereditary predisposition to ovarian cancer, looking beyond BRCA1/BRCA2
AbstractObjectiveGenetic predisposition to ovarian cancer is well documented. With the advent of next generation sequencing, hereditary panel testing provides an efficient method for evaluating multiple genes simultaneously. Therefore, we sought to investigate the contribution of 19 genes identified in the literature as increasing the risk of hereditary breast and ovarian cancer (HBOC) in a BRCA1 and BRCA2 negative population of patients with a personal history of breast and/or ovarian cancer by means of a hereditary cancer panel.MethodsSubjects were referred for multi-gene panel testing between February 2012 and March 2014. Clinical data was ascertained from requisition forms. The incidence of pathogenic mutations (including likely pathogenic), and variant of unknown significance were then calculated for each gene and/or patient cohort.ResultsIn this cohort of 911 subjects, panel testing identified 67 mutations. With 7.4% of subjects harboring a mutation on this multi-gene panel, the diagnostic yield was increased, compared to testing for BRCA1 and BRCA2 mutations alone. In the ovarian cancer probands, the most frequently mutated genes were BRIP1 (n=8; 1.72%) and MSH6 (n=6; 1.29%). In the breast cancer probands, mutations were most commonly observed in CHEK2 (n=9; 2.54%), ATM (n=3; 0.85%), and TP53 (n=3; 0.85%).ConclusionsAlthough further studies are needed to clarify the exact management of patients with a mutation in each gene, this study highlights information that can be captured with panel testing and provides support for incorporation of panel testing into clinical practice
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