2,144 research outputs found
Production of intense highly charged ion beams with SERSE
The source SERSE is operational at LNS since June 1998 and many improvements have been carried out in this period. The frequency has been increased from 14.5 GHz to 18 GHz and the use of two frequency heating has given positive results. Metallic ion production has been tested by means of a high temperature oven and the preliminary results are described. Tests of magnetic field scaling and frequency scaling have confirmed the results of previous tests with SC-ECRIS at lower frequency and seems to suggest that the upgrading of the source to higher frequency may be considered
Summary of the performances of the superconducting electron cyclotron resonance ion source at 14 GHz
This article deals with the most recent performance of the superconducting electron cyclotron resonance ion source (SERSE) working at 14 GHz with high magnetic fields after the required conditioning and optimization of several operating parameters. SERSE has now achieved an outstanding level of performance in delivering highly charged ion beams in argon and oxygen gases: the results obtained while operating in a stainless steel chamber and with an aluminum liner are shown and discussed
Deep Optical Imaging of A Compact Group of Galaxies, Seyfert's Sextet
In order to investigate the dynamical status of Seyfert's Sextet (SS), we
have obtained a deep optical () image of this group. Our image shows that
a faint envelope, down to a surface brightness (AB) mag arcsec, surrounds the member galaxies. This envelope is
irregular in shape. It is likely that this shape is attributed either to
recent-past or to on-going galaxy interactions in SS. If the member galaxies
have experienced a number of mutual interactions over a long timescale, the
shape of the envelope should be rounder. Therefore, the irregular-shaped
morphology suggests that SS is in an early phase of dynamical interaction among
the member galaxies. It is interesting to note that the soft X-ray image
obtained with ROSAT (Pildis et al. 1995) is significantly similar in
morphology. We discuss the possible future evolution of SS briefly.Comment: 7 pages text (emulateapj LaTeX), 8 figures (3 EPS files, 1 PostScript
file, and 4 jpeg files) figures, The Astronomical Journal, 120, No. 5 inpres
RA-specific expression profiles and new candidate genes
Objective:
To identify rheumatoid arthritis- (RA)-specific profiles of differentially expressed genes.
Methods:
Synovial tissues from RA and osteoarthritis (OA) patients and from normal joints were selected according to their disease-characteristic histology. Gene expression was analyzed using DNA microarrays (GeneChip; Unigene-array) and representational difference analysis (RDA). Data were validated on larger cohorts of patients by RT-PCR.
Results:
Nine hundred and eighty genes were significantly regulated in RA synovial tissue as compared with non-RA. Specialized cluster analysis identified a set of 312 genes as sufficient of unequivocally discriminating RA from non-RA patterns (class discovery). Genes of highest regulation were associated with leukocyte activation (chemokines, chemokine receptors, B- and T-cell genes), endothelial and angiogenic
activation, tissue destruction and remodelling [MMP-3, BMP-4, TIMPs]. Interestingly, a large set of genes was down-regulated in RA (TGF-β superfamily, apoptosis-related genes, transcription factors). Osteopontin-like genes (n=46) — up-regulated in RA — and glutathione peroxidase-3-like genes (n=85) — down-regulated in RA — yielded the highest correlation coefficients (>0.94). Megakaryocyte stimulating factor (MSF), down-regulated in a subset of RA, may hold the key to subclassification: a loss-of-function mutation in the MSF-encoding gene leads to synovial hyperplasia in camptodactyly–arthropathy–coxa vara–pericarditis syndrome, and, as in RA, also to pericardial involvement. A further candidate, vitamin-D3-up-regulated protein-1 (VDUP-1), is regulated like MSF and predisposes to premature coronary artery disease when mutated, again a feature of a subset of RA.
Conclusion:
RA specific gene profiles were identified and are useful to improve diagnostics of the disease. Novel gene candidates not yet in the focus of RA pathogenesis have been identified that are likely to further the understanding of RA
On the origin of the O and B-type stars with high velocities II Runaway stars and pulsars ejected from the nearby young stellar groups
We use milli-arcsecond accuracy astrometry (proper motions and parallaxes)
from Hipparcos and from radio observations to retrace the orbits of 56 runaway
stars and nine compact objects with distances less than 700 pc, to identify the
parent stellar group. It is possible to deduce the specific formation scenario
with near certainty for two cases. (i) We find that the runaway star zeta
Ophiuchi and the pulsar PSR J1932+1059 originated about 1 Myr ago in a
supernova explosion in a binary in the Upper Scorpius subgroup of the Sco OB2
association. The pulsar received a kick velocity of about 350 km/s in this
event, which dissociated the binary, and gave zeta Oph its large space
velocity. (ii) Blaauw & Morgan and Gies & Bolton already postulated a common
origin for the runaway-pair AE Aur and mu Col, possibly involving the massive
highly-eccentric binary iota Ori, based on their equal and opposite velocities.
We demonstrate that these three objects indeed occupied a very small volume
\sim 2.5Myr ago, and show that they were ejected from the nascent Trapezium
cluster.
We identify the parent group for two more pulsars: both likely originate in
the 50 Myr old association Per OB3, which contains the open cluster alpha
Persei. At least 21 of the 56 runaway stars in our sample can be linked to the
nearby associations and young open clusters. These include the classical
runaways 53 Arietis (Ori OB1), xi Persei (Per OB2), and lambda Cephei (Cep
OB3), and fifteen new identifications, amongst which a pair of stars running
away in opposite directions from the region containing the lambda Ori cluster.
Other currently nearby runaways and pulsars originated beyond 700 pc, where our
knowledge of the parent groups is very incomplete.Comment: Accepted for publication in the A&A. 29 pages, 19 figure
Observational Evidence for Massive Black Holes in the Centers of Active Galaxies
Naturally occurring water vapor maser emission at 1.35 cm wavelength provides
an accurate probe for the study of accretion disks around highly compact
objects, thought to be black holes, in the centers of active galaxies. Because
of the exceptionally fine angular resolution, 200 microarcseconds, obtainable
with very long baseline interferometry, accompanied by high spectral
resolution, < 0.1 km/s, the dynamics and structures of these disks can be
probed with exceptional clarity. The data on the galaxy NGC4258 are discussed
here in detail. The mass of the black hole binding the accretion disk is 3.9
times 10^7 solar masses. Although the accretion disk has a rotational period of
about 800 years, the physical motions of the masers have been directly measured
with VLBI over a period of a few years. These measurements also allow the
distance from the earth to the black hole to be estimated to an accuracy of 4
percent. The status of the search for other maser/black hole candidates is also
discussed.Comment: 24 pages, 11 figures, latex, uses aaspp4 style file. To be published
in the Journal of Astronomy and Astrophysics (India), proceedings of the
Discussion Meeting on the Physics of Black Holes, Bangalore, India: December
199
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 -> phi gamma has been measured using 0.37 fb-1 of pp collisions at a
centre of mass energy of sqrt(s) = 7 TeV, collected by the LHCb experiment. The
value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.12 +/- 0.08
^{+0.06}_{-0.04} ^{+0.09}_{-0.08}, where the first uncertainty is statistical,
the second systematic and the third is associated to the ratio of fragmentation
fractions fs/fd. Using the world average for BR(B0 -> K*0 gamma) = (4.33 +/-
0.15) x 10^{-5}, the branching fraction BR(Bs0 -> phi gamma) is measured to be
(3.9 +/- 0.5) x 10^{-5}, which is the most precise measurement to date.Comment: 15 pages, 1 figure, 2 table
Measurement of the CKM angle γ from a combination of B±→Dh± analyses
A combination of three LHCb measurements of the CKM angle γ is presented. The decays B±→D K± and
B±→Dπ± are used, where D denotes an admixture of D0 and D0 mesons, decaying into K+K−, π+π−, K±π∓, K±π∓π±π∓, K0Sπ+π−, or K0S K+K− final states. All measurements use a dataset corresponding to 1.0 fb−1 of integrated luminosity. Combining results from B±→D K± decays alone a best-fit value of
γ =72.0◦ is found, and confidence intervals are set
γ ∈ [56.4,86.7]◦ at 68% CL,
γ ∈ [42.6,99.6]◦ at 95% CL.
The best-fit value of γ found from a combination of results from B±→Dπ± decays alone, is γ =18.9◦,
and the confidence intervals
γ ∈ [7.4,99.2]◦ ∪ [167.9,176.4]◦ at 68% CL
are set, without constraint at 95% CL. The combination of results from B± → D K± and B± → Dπ±
decays gives a best-fit value of γ =72.6◦ and the confidence intervals
γ ∈ [55.4,82.3]◦ at 68% CL,
γ ∈ [40.2,92.7]◦ at 95% CL
are set. All values are expressed modulo 180◦, and are obtained taking into account the effect of D0–D0
mixing
Desafio anatômico: uma metodologia capaz de auxiliar no aprendizado de anatomia humana
In 2007 the city of Cajazeiras-PB received the implantation of the School of Medicine from Federal University of Campina Grande. In this process professors were faced with several difficulties. To propose improvements and even supplementation in Anatomy concepts, they created a didactic activity called “Anatomical Challenge” in which the students were instructed to fabricate didactical anatomical models to be used in classrooms, helping the content of the discipline. After work, the students were satisfied with the results, especially from the point of view of knowledge transmission and absorption of content. Thus, this experience was positive and unique to the process of teaching and learning of anatomy in medical school, because it stimulated creativity in many ways, memory and group working by the participants.Em 2007 a cidade de Cajazeiras-PB recebeu a implantação do curso de Medicina pela Universidade Federal de Campina Grande. Neste processo, os docentes se depararam com várias dificuldades. Para propor melhoras e até, suplementação da carga de conceitos em Anatomia Humana, foi criada uma atividade didática chamada “Desafio Anatômico”, no qual os discentes eram instruídos a confeccionar modelos anatômicos que fossem didáticos a ponto de serem usados nas aulas, auxiliando o conteúdoda disciplina. Após a apresentação dos trabalhos, os discentes mostraram-se satisfeitos com os resultados, sobretudo sob o ponto de vista de transmissão de conhecimento e absorção de conteúdo. Desta maneira, esta experiência mostrou-se positiva e singular para o processo de ensino-aprendizagem da anatomia no curso médico, pois a mesma estimulou de diversas formas a criatividade, memória e trabalho em grupo dos participantes
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