4,630 research outputs found
IUE observations of Herbig-Haro and related objects
The I.U.E. spectra of the Herbig-Haro objectives H-H 1, H-H 2H, H-H 2G and H-H 32 A are considered. In order to obtain a better understanding of the physics of these intriguing objects and of the formation of the ultraviolet continua and emission lines in H-H objects, the UV spectra of the Cohen-Schwartz star, the T Tauri star AS 353A, and of the reflection nebula NGC 1999 (which is illuminated by the young object V 380 Orionis), are also examined
The ultraviolet spectrum of HH 24A and its relation to optical spectra
The spectrum of the brightest part (HH 24A) of the complex Herbig-Haro object HH 24 in the short wavelength UV range was studied. The object is of special interest since it is known that in the optical range the continuum is due to dust scattered light originating in a young stellar object while the shock excited emission lines are formed in HH 24A itself. The spectrum shows only a continuum or a quasi-continuum and is not comparable to that of the typical high excitation object like HH1 or HH2 nor to that of a low excitation object like HH3 or HH47
Nuclear deformation and neutrinoless double- decay of Zr, Mo, Ru, Pd, Te and Nd nuclei in mass mechanism
The decay of Zr, Mo,
Ru, Pd, Te and Nd isotopes for the
transition is studied in the Projected Hartree-Fock-Bogoliubov
framework. In our earlier work, the reliability of HFB intrinsic wave functions
participating in the decay of the above mentioned nuclei
has been established by obtaining an overall agreement between the
theoretically calculated spectroscopic properties, namely yrast spectra,
reduced : transition probabilities, quadrupole moments
, gyromagnetic factors as well as half-lives
for the transition and the available
experimental data. In the present work, we study the decay for the transition in the mass mechanism
and extract limits on effective mass of light as well as heavy neutrinos from
the observed half-lives using nuclear
transition matrix elements calculated with the same set of wave functions.
Further, the effect of deformation on the nuclear transition matrix elements
required to study the decay in the mass
mechanism is investigated. It is noticed that the deformation effect on nuclear
transition matrix elements is of approximately same magnitude in and decay.Comment: 15 pages, 1 figur
Arts therapies for anxiety, depression, and quality of life in breast cancer patients: A systematic review and meta-analysis
Background. Breast cancer is one of the most common types of cancer. However, only a few trials assess the effects of arts therapies. Material and Methods. We searched the Cochrane Central Register of Controlled Trials, PubMed, and Google Scholar from their start date to January 2012. We handsearched reference lists and contacted experts. All randomized controlled trials, quasi-randomized trials, and controlled clinical trials of art interventions in breast cancer patients were included. Data were extracted and risk of bias was assessed. Meta-analyses were performed using standardized mean differences. Results. Thirteen trials with a total of 606 patients were included. Arts therapies comprised music therapy interventions, various types of art therapy, and dance/movement therapies. The methodological quality ranged from poor to high quality with the majority scoring 3 of 4 points on the Jadad scale. Results suggest that arts therapies seem to positively affect patients' anxiety (standardized mean difference: -1.10; 95%, confidence interval: -1.40 to -0.80) but not depression or quality of life. No conclusion could be drawn regarding the effects of arts therapy on pain, functional assessment, coping, and mood states. Discussion. Our review indicates that arts interventions may have beneficial effects on anxiety in patients with breast cancer. © 2014 Katja Boehm et al
A high-reflectivity high-Q micromechanical Bragg-mirror
We report on the fabrication and characterization of a micromechanical
oscillator consisting only of a free-standing dielectric Bragg mirror with high
optical reflectivity and high mechanical quality. The fabrication technique is
a hybrid approach involving laser ablation and dry etching. The mirror has a
reflectivity of 99.6%, a mass of 400ng, and a mechanical quality factor Q of
approximately 10^4. Using this micromirror in a Fabry Perot cavity, a finesse
of 500 has been achieved. This is an important step towards designing tunable
high-Q high-finesse cavities on chip.Comment: 3 pages, 2 figure
Determination of Strong-Interaction Widths and Shifts of Pionic X-Rays with a Crystal Spectrometer
Pionic 3d-2p atomic transitions in F, Na, and Mg have been studied using a bent crystal spectrometer. The pionic atoms were formed in the production target placed in the external proton beam of the Space Radiation Effects Laboratory synchrocyclotron. The observed energies and widths of the transitions are E=41679(3) eV and Γ=21(8) eV, E=62434(18) eV and Γ=22(80) eV, E=74389(9) eV and Γ=67(35) eV, in F, Na, and Mg, respectively. The results are compared with calculations based on a pion-nucleus optical potential
Some Findings Concerning Requirements in Agile Methodologies
gile methods have appeared as an attractive alternative to conventional methodologies. These methods try to reduce the time to market and, indirectly, the cost of the product through flexible development and deep customer involvement. The processes related to requirements have been extensively studied in literature, in most cases in the frame of conventional methods. However, conclusions of conventional methodologies could not be necessarily valid for Agile; in some issues, conventional and Agile processes are radically different. As recent surveys report, inadequate project requirements is one of the most conflictive issues in agile approaches and better understanding about this is needed. This paper describes some findings concerning requirements activities in a project developed under an agile methodology. The project intended to evolve an existing product and, therefore, some background information was available. The major difficulties encountered were related to non-functional needs and management of requirements dependencies
Electronic and magnetic properties of substitutional Mn clusters in (Ga,Mn)As
The magnetization and hole distribution of Mn clusters in (Ga,Mn)As are
investigated by all-electron total energy calculations using the projector
augmented wave method within the density-functional formalism. It is found that
the energetically most favorable clusters consist of Mn atoms surrounding one
center As atom. As the Mn cluster grows the hole band at the Fermi level splits
increasingly and the hole distribution gets increasingly localized at the
center As atom. The hole distribution at large distances from the cluster does
not depend significantly on the cluster size. As a consequence, the spin-flip
energy differences of distant clusters are essentially independent of the
cluster size. The Curie temperature is estimated directly from these
spin-flip energies in the mean field approximation. When clusters are present
estimated values are around 250 K independent of Mn concentration whereas
for a uniform Mn distribution we estimate a of about 600 K.Comment: 7 pages, 5 figures, 2 tables; Revised manuscript 26. May 200
Self-cooling of a micro-mirror by radiation pressure
We demonstrate passive feedback cooling of a mechanical resonator based on
radiation pressure forces and assisted by photothermal forces in a high-finesse
optical cavity. The resonator is a free-standing high-reflectance micro-mirror
(of mass m=400ng and mechanical quality factor Q=10^4) that is used as
back-mirror in a detuned Fabry-Perot cavity of optical finesse F=500. We
observe an increased damping in the dynamics of the mechanical oscillator by a
factor of 30 and a corresponding cooling of the oscillator modes below 10 K
starting from room temperature. This effect is an important ingredient for
recently proposed schemes to prepare quantum entanglement of macroscopic
mechanical oscillators.Comment: 11 pages, 9 figures, minor correction
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