3,414 research outputs found
Infalling Faint [OII] Emitters in Abell 851. I. Spectroscopic Confirmation of Narrowband-Selected Objects
We report on a spectroscopic confirmation of narrowband-selected [OII]
emitters in Abell 851 catalogued by Martin et al. (2000). The optical spectra
obtained from the Keck I Low Resolution Imaging Spectrometer (LRIS) and Keck II
Deep Imaging Multi-Object Spectrograph (DEIMOS) have confirmed [OII]3727
emission in narrowband-selected cluster [OII] candidates at a 85% success rate
for faint (i <~ 25) blue (g-i < 1) galaxies. The rate for the successful
detection of [OII] emission is a strong function of galaxy color, generally
proving the efficacy of narrowband [OII] search supplemented with broadband
colors in selecting faint cluster galaxies with recent star formation. Balmer
decrement-derived reddening measurements show a high degree of reddening
[E(B-V) >~ 0.5] in a significant fraction of this population. Even after
correcting for dust extinction, the [OII]/Ha line flux ratio for the
high-E(B-V) galaxies remains generally lower by a factor of ~2 than the mean
[OII]/Ha ratios reported by the studies of nearby galaxies. The strength of
[OII] equivalent width shows a negative trend with galaxy luminosity while the
Ha equivalent width does not appear to depend as strongly on luminosity. This
in part is due to the high amount of reddening observed in luminous galaxies.
Furthermore, emission line ratio diagnostics show that AGN-like galaxies are
abundant in the high luminosity end of the cluster [OII]-emitting sample, with
only moderately strong [OII] equivalent widths, consistent with a scenario of
galaxy evolution connecting AGNs and suppression of star-forming activity in
massive galaxies.Comment: 11 pages (LaTeX emulateapj), 8 figures, to appear in ApJ. A version
with high resolution figures available from the lead autho
How is modern bedside teaching structured? A video analysis of learning content, social and spatial structures
BACKGROUND: Bedside teaching (BST) is an essential and traditional clinical teaching format. It has been subject to various impediments and has transformed over time. Besides a decrease in bedside time, there has also been a didactic diversification. In order to use time at the bedside effectively and understand the current design of BST, we here offer an evidence-based insight into how BST is practiced. This may serve as a basis for a refinement of its didactic design. METHODS: In the current study, we investigate the interrelationships between learning content and the social as well as spatial structures of BST. To this end, we have empirically analysed almost 80 hours of video material from a total of 36 BST sessions with good interrater reliability. RESULTS: BST lasted on average 125 min, most of which was spent in plenary and less than a third of the time at the patient’s bedside. History taking was primarily practiced at the bedside while case presentations, clinical reasoning and theoretical knowledge were largely taught away from the patient. Clinical examination took place to a similar extent in the patient’s room and in the theory room. CONCLUSIONS: Even though the filmed BSTs are not purely “bedside”, the teaching format investigated here is a typical example of undergraduate medical education. In order to maximize the teaching time available, a suitable learning space should be provided in addition to the bedside. Moreover, the clinical examination should be revised in its general sequence prior to the BST, and conscious decisions should be made regarding the social structure so as to optimize the potential of small groups and plenary sessions
Iterative Phase Optimization of Elementary Quantum Error Correcting Codes
Performing experiments on small-scale quantum computers is certainly a challenging endeavor. Many parameters need to be optimized to achieve high-fidelity operations. This can be done efficiently for operations acting on single qubits, as errors can be fully characterized. For multiqubit operations, though, this is no longer the case, as in the most general case, analyzing the effect of the operation on the system requires a full state tomography for which resources scale exponentially with the system size. Furthermore, in recent experiments, additional electronic levels beyond the two-level system encoding the qubit have been used to enhance the capabilities of quantum-information processors, which additionally increases the number of parameters that need to be controlled. For the optimization of the experimental system for a given task (e.g., a quantum algorithm), one has to find a satisfactory error model and also efficient observables to estimate the parameters of the model. In this manuscript, we demonstrate a method to optimize the encoding procedure for a small quantum error correction code in the presence of unknown but constant phase shifts. The method, which we implement here on a small-scale linear ion-trap quantum computer, is readily applicable to other AMO platforms for quantum-information processing
Quantum computations on a topologically encoded qubit
The construction of a quantum computer remains a fundamental scientific and technological challenge, in particular due to unavoidable noise. Quantum states and operations can be protected from errors using protocols for fault-tolerant quantum computing (FTQC). Here we present a step towards this by implementing a quantum error correcting code, encoding one qubit in entangled states distributed over 7 trapped-ion qubits. We demonstrate the capability of the code to detect one bit flip, phase flip or a combined error of both, regardless on which of the qubits they occur. Furthermore, we apply combinations of the entire set of logical single-qubit Clifford gates on the encoded qubit to explore its computational capabilities. The implemented 7-qubit code is the first realization of a complete Calderbank-Shor-Steane (CSS) code and constitutes a central building block for FTQC schemes based on concatenated elementary quantum codes. It also represents the smallest fully functional instance of the color code, opening a route towards topological FTQC
Qualidade de Vida e Atitudes dos Idosos Face à Velhice
A problemática do envelhecimento tem assumido, nos últimos anos, uma
crescente importância na consciência coletiva da população, tornando-se cada vez mais importante compreender a população idosa e a sua realidade.
Posto isto, foi realizado um estudo quantitativo e correlacional, que teve como
objectivo avaliar a qualidade de vida e atitudes face à velhice de idosos, bem como a
relação entre estas e as variáveis sociodemográficas e familiares.
Foram inquiridos 100 idosos, com mais de 65 anos e sem deficit cognitivo . Para
a recolha de dados utilizou-se uma entrevista estruturada, constituída dados
sóciodemográficos do idoso, WHOQOL-AGE (Caballero, Miret, Power, Chatterji,
Tobiasz-Adamczyk, Koskinen, Leonardi, Olaya, Haro &Ayuso-Mateos, 2013) e o AAQ
( Laidlaw, Power, Schmidt and the WHOQOL-OLD Group, 2007).
Dos resultados destacamos os seguintes: A amostra é constituída por 52% de
idosos do sexo masculino tendo uma média de idades de 74,7 (DP=6,8). È no fator
Perdas Psicossociais e no Desenvolvimento Psicológico que os idosos têm uma melhor
atitude face ao envelhecimento. É no item “Tem dinheiro suficiente para satisfazer as
suas necessidades?” que os idosos apresentam uma menor qualidade de vida.
Não ter doença diagnosticada e ser do sexo masculino permitem ter melhores
atitudes face ao envelhecimento.
A Qualidade de Vida está relacionada com a idade, com o estado de saúde e com
a intensidade de preocupação da família. Constatou-se que os idosos que não estão
institucionalizados apresentam uma melhor qualidade de vida e uma melhor atitude face à velhice. Quem não precisa de ajudas técnicas para se movimentar apresenta uma melhor qualidade de vida.
Diferenças nas atitudes face ao envelhecimento consoante a residência onde
habita são significativas nas mudanças físicas e no desenvolvimento psicológico sendo
que os idosos que não vivem em lares têm uma atitude mais positiva em ambos os
fatores. / Over the past few years the issue of aging has played a growing importance in the population`s collective consciousness becoming increasingly important to
understand the elderly population and this reality.
Therefore a quantitative correlational study was performed to assess the quality
of life of seniors and their attitudes towards old age, and the relationship between these
and the socio-demographic and family factors.
100 seniors with more than 65 years and without cognitive deficit were
surveyed. For data collection we used a structured interview consisting of sociodemographic data of the elderly, WHOQOL-AGE (Caballero Miret Power Chatterji
Tobiasz-Adamczyk Koskinen Leonardi Olaya Ayuso-Mateos & Haro 2013) and AAQ
(Laidlaw Power Schmidt and the WHOQOL-OLD Group 2007).
We highlight: The sample is composed of 52% of males with a mean age of 74.7
(SD = 6.8). It is in the factor Psychosocial Losses and Psychological Development that
elderly people have a better attitude towards aging. It is in the item "Do you have
enough money to meet your needs?" that seniors show less quality of life.
Not having illness and being male allows having better attitudes towards aging.
Quality of Life is related to age, health condition and the intensity of family
concerns. It was observed that the elderly who are not institutionalized have a better
quality of life and a better attitude towards old age. Who does not need assistive devices to move around has a better quality of life.
Differences in attitudes towards aging, according to residency, are significant in
physical changes and psychological development, thus verifying that elderly who do not
live in nursing homes have a more positive attitude in both factors
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Focal Plane Metrology for the LSST Camera
Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane
Revisiting Scalar and Pseudoscalar Couplings with Nucleons
Certain dark matter interactions with nuclei are mediated possibly by a
scalar or pseudoscalar Higgs boson. The estimation of the corresponding cross
sections requires a correct evaluation of the couplings between the scalar or
pseudoscalar Higgs boson and the nucleons. Progress has been made in two
aspects relevant to this study in the past few years. First, recent lattice
calculations show that the strange-quark sigma term and the
strange-quark content in the nucleon are much smaller than what are expected
previously. Second, lattice and model analyses imply sizable SU(3) breaking
effects in the determination on the axial-vector coupling constant that
in turn affect the extraction of the isosinglet coupling and the
strange quark spin component from polarized deep inelastic
scattering experiments. Based on these new developments, we re-evaluate the
relevant nucleon matrix elements and compute the scalar and pseudoscalar
couplings of the proton and neutron. We also find that the strange quark
contribution in both types of couplings is smaller than previously thought.Comment: 17 pages, Sec. II is revised and the pion-nucleon sigma term
extracted from the scattering data is discussed. Version to appear in JHE
Chiral effective theory with a light scalar and lattice QCD
We extend the usual chiral perturbation theory framework (PT) to allow
the inclusion of a light dynamical isosinglet scalar. Using lattice QCD
results, and a few phenomenological inputs, we explore the parameter space of
the effective theory. We discuss the S-wave pion-pion scattering lengths,
extract the average value of the two light quark masses and evaluate the impact
of the dynamical singlet field in the low--energy constants ,
and of PT. We also show how to extract the mass
and width of the sigma resonance from chiral extrapolations of lattice QCD
data.Comment: Journal version. Added the study of the scalar two-point function and
a discussion of the analytical properties of the sigma pole and its
dependence on the quark masses. We clarified the relation of PT with
unitarized PT. Figures 6 and 8 have been improved. 28 pages, 2 tables, 8
figure
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