2,473 research outputs found
Clarification of the Nature of the Galaxy CFC97 Cen 05
The galaxy CFC97 Cen 05 has in the past been considered an HI-rich dwarf
galaxy in the nearby Centaurus A group. We have used Australia Telescope
Compact Array observations to show that the HI associated with CFC97 Cen 05 by
Cote et al. (1997) is most likely a Galactic High Velocity Cloud that is
centered ~17' from the optical image of the galaxy. At the optical location of
the galaxy, which is not that tabulated by Banks et al. (1999), there is no
indication of the presence of HI for velocities less than the upper limit of
the HIPASS survey at ~12,500 km/s. In addition, WFPC2 images of CFC97 Cen 05
obtained from the HST Archive reveal that this galaxy is in fact not a dwarf at
all, but rather is a distant background spiral not associated with the
Centaurus A group.Comment: accepted for publication in the PASP (November 2004
Detection of neutral hydrogen in early-type dwarf galaxies of the Sculptor Group
We present our results of deep 21 cm line (HI) observations of five early and
mixed-type dwarf galaxies in the nearby Sculptor group using the ATNF 64m
Parkes Radio Telescope. Four of these objects, ESO294-G010, ESO410-G005,
ESO540-G030, and ESO540-G032, were detected in HI with neutral hydrogen masses
in the range of 2-9x10^5 M_{\odot} ( = 0.08, 0.13, 0.16, and
0.18, respectively). These HI masses are consistent with the gas mass expected
from stellar outflows over a large period of time. Higher resolution radio data
from the Australia Telescope Compact Array were further analysed to measure
more accurate positions and the distribution of the HI gas. In the cases of
dwarfs ESO294-G010 and ESO540-G030, we find significant offsets of 290 pc and
460 pc, respectively, between the position of the HI peak flux and the center
of the stellar component. These offsets are likely to have internal cause such
as the winds from star-forming regions. The fifth object, the spatially
isolated dwarf elliptical Scl-dE1, remains undetected at our 3\sigma limit of
22.5 mJy km/s and thus must contain less than 10^5 M_{\odot} of neutral
hydrogen. This leaves Scl-dE1 as the only Sculptor group galaxy known where no
interstellar medium has been found to date. The object joins a list of similar
systems including the Local Group dwarfs Tucana and Cetus that do not fit into
the global picture of the morphology-density relation where gas-rich dwarf
irregulars are in relative isolation and gas-deficient dwarf ellipticals are
satellites of more luminous galaxies.Comment: 21 pages, 4 figures, to be published in AJ (accepted
Building a game scenario to encourage children with autism to recognize and label emotions using a humanoid robot
This paper presents an exploratory study in which children with autism interact with ZECA (Zeno Engaging Children with Autism). ZECA is a humanoid robot with a face covered with a material allowing the display of varied facial expressions. The study investigates a novel scenario for robot-assisted play, to help promoting labelling of emotions by children with autism spectrum disorders (ASD). The study was performed during three sessions with two boys diagnosed with ASD. The results obtained from the analysis of the children's behaviours while interacting with ZECA helped us improve several aspects of our game scenario such as the technical specificities of the game and its dynamics, and the experimental setup. The software produced for this study allows the robot to autonomously identify the answers of the child during the session. This automatic identification helped the fluidity of the game and freed the experimenter to participate in triadic interactions with the child. The evaluation of the game scenario that will be used in a future study was the main goal of this pilot study, rather than to quantify and evaluate the performance of the children. Overall, this exploratory study in teaching children about labelling emotions using a humanoid robot embedded in a game scenario demonstrated the possible positive outcomes this child-robot interaction can produce and highlighted the issues regarding data collection and their analysis that will inform future studies.Fundação para a Ciencia e Tecnologia in the scope of the project:
PEst-OE/EEI/UI0319/2014.
The authors are grateful to the Portuguese Foundation for the R&D project
RIPD/ADA/109407/2009 and SFRH/BD/71600/2010 scholarshipinfo:eu-repo/semantics/publishedVersio
Use of the continuity equation for transesophageal Doppler assessment of severity of proximal left coronary artery stenosis: a quantitative coronary angiography validation study
AbstractObjectives. We tested the value of transesophageal Doppler echocardiography (TEDE) for quantitating proximal left coronary artery (LCA) stenosis by using the continuity equation.Background. The continuity equation applied to a stenosis states that the ratio of the time–velocity integral (TVI) of prestenotic to stenotic flow velocities is equal to the ratio of stenotic to prestenotic cross-sectional areas. TEDE allows the measurement of coronary blood flow velocities within the proximal part of the LCA.Methods. Forty-one patients with a stenosis of the proximal or mid left anterior descending coronary artery or with a nonostial stenosis of the left main coronary artery were studied. Coronary flow velocities were recorded by TEDE guided by color flow imaging. Prestenotic velocities were recorded by pulsed Doppler echocardiography and transstenotic velocities were recorded by pulsed or high pulse repetition frequency or continuous wave Doppler echocardiography. The prestenotic and transstenotic diastolic TVIs were calculated and the TEDE-derived percent area stenosis was calculated as (1 − TVI ratio) × 100. Quantitative angiography lesion analysis was performed using a computer-assisted automated edge-detection system.Results. TEDE recordings were successful in 35 of the 41 patients. A good linear correlation was found between TEDE and quantitative angiographically derived percent area stenosis (r = 0.89, p = 0.0001, SEE 5.7). However, TEDE measurements underestimated the actual percent area stenosis (slope of regression 0.54). A better agreement (slope 1.08) was obtained after dividing prestenotic velocity by 2 in the continuity equation, based on the assumption of a parabolic cross-sectional velocity profile in the prestenotic segment.Conclusions. TEDE may be used for quantitating stenosis of the proximal part of the LCA with the use of a modified continuity equation that takes into account the parabolic velocity profile in the normal prestenotic segment
Interstellar medium disruption in the Centaurus A group
We present the results of a 21 cm neutral hydrogen (HI) line detection
experiment in the direction of 18 low luminosity dwarf galaxies of the
Centaurus A group, using the Australia Telescope National Facility 64m Parkes
Radio Telescope and the Australia Telescope Compact Array. Five dwarfs have HI
masses between M_HI=4x10^5 to M_HI=2.1x10^7 Msol and 0.04<M_HI/L_B<1.81 Msol
L_{sol, B}^-1. The other 13 have upper-limits between M_HI<5x10^5 and
M_HI<4x10^6 Msol (M_HI}/L_B<0.24 Msol L_{sol, B}^-1). Two of the
mixed-morphology dwarfs remain undetected in HI, a situation that is in
contrast to that of similar Local Group and Sculptor group objects where all
contain significant amounts of neutral gas. There is a discontinuity in the HI
properties of Centaurus A group low luminosity dwarfs that is unobserved
amongst Sculptor group dwarfs. All objects fainter than M_B=-13 have either
M_HI>10^7 Msol or M_HI<10^6 Msol. This gap may be explained by the ram pressure
stripping mechanism at work in this dense environment where all galaxies with
M_HI<10^7 Msol have been stripped of their gas. The required intergalactic
medium density to achieve this is ~10^-3 cm^-3.Comment: 7 figures, 2 table
A pilot study using imitation and storytelling scenarios as activities for labelling emotions by children with autism using a humanoid robot
In this paper we present a child-robot interaction pilot study, focusing on recognizing and labelling emotions displayed by a humanoid robot. ZECA (Zeno Engaging Children with Autism) has a special skin covering its face which allows the display of facial expressions representing five emotions: joy, sadness, fear, anger, and surprise. These facial expressions were used in two different game scenarios, involving imitation and storytelling activities. The goal of these scenarios is to help the child acquire knowledge about different emotions and to improve their skill in recognizing them. The results show that these scenarios are appropriate for the goal established for this study, and positive behaviours concerning non-verbal communication were observed. This exploratory study demonstrated the possible positive outcomes this child-robot interaction can produce and highlighted the issues regarding data collection and their analysis that will inform future studies.This work has been supported by FCT Fundação para
a Ciência e Tecnologia in the scope of the project:
PEst-OE/EEI/UI0319/2014. The authors are grateful to
the Portuguese Foundation (FCT) for the R&D project
RIPD/ADA/109407/2009 and SFRH/BD/71600/2010 scholarship.info:eu-repo/semantics/publishedVersio
The Environmental Influence on the Evolution of Local Galaxies
The results of an Halpha photometric survey of 30 dwarf galaxies of various
morphologies in the Centaurus A and Sculptor groups are presented. Of these 30,
emission was detected in 13: eight are of late-type, two are early-type and
three are of mixed-morphology. The typical flux detection limit of 2e-16 erg
s-1 cm-2, translates into a Star Formation Rate (SFR) detection limit of 4e-6
M_sol yr-1 . In the light of these results, the morphology-density relation is
reexamined: It is shown that, despite a number of unaccounted parameters, there
are significant correlations between the factors determining the morphological
type of a galaxy and its environment. Dwarf galaxies in high density regions
have lower current SFR and lower neutral gas content than their low density
counterparts, confirming earlier results from the Local Group and other denser
environments. The effect of environment is also seen in the timescale formed
from the ratio of blue luminosity to current SFR - dwarfs in higher density
environments have larger values, indicating relatively higher past average SFR.
The influence of environment extends very far and no dwarfs from our sample can
be identified as 'field' objects.Comment: 23 pages, 9 figures, accepted in A
Effects of remote monitoring on clinical outcomes and use of healthcare resources in heart failure patients with biventricular defibrillators: results of the MORE-CARE multicentre randomized controlled trial
Aims: The aim of this study was to evaluate the clinical efficacy and safety of remote monitoring in patients with heart failure implanted with a biventricular defibrillator (CRT-D) with advanced diagnostics. Methods and results: The MORE-CARE trial is an international, prospective, multicentre, randomized controlled trial. Within 8 weeks of de novo implant of a CRT-D, patients were randomized to undergo remote checks alternating with in-office follow-ups (Remote arm) or in-office follow-ups alone (Standard arm). The primary endpoint was a composite of death and cardiovascular (CV) and device-related hospitalization. Use of healthcare resources was also evaluated. A total of 865 eligible patients (mean age 66 \ub1 10 years) were included in the final analysis (437 in the Remote arm and 428 in the Standard arm) and followed for a median of 24 (interquartile range = 15\u201326) months. No significant difference was found in the primary endpoint between the Remote and Standard arms [hazard ratio 1.02, 95% confidence interval (CI) 0.80\u20131.30, P = 0.89] or in the individual components of the primary endpoint (P > 0.05). For the composite endpoint of healthcare resource utilization (i.e. 2-year rates of CV hospitalizations, CV emergency department admissions, and CV in-office follow-ups), a significant 38% reduction was found in the Remote vs. Standard arm (incidence rate ratio 0.62, 95% CI 0.58\u20130.66, P < 0.001) mainly driven by a reduction of in-office visits. Conclusions: In heart failure patients implanted with a CRT-D, remote monitoring did not reduce mortality or risk of CV or device-related hospitalization. Use of healthcare resources was significantly reduced as a result of a marked reduction of in-office visits without compromising patient safety. Trial registration: NCT00885677
Blade debitage in Southern Brazil: We have cores! [Debitagem laminar no Sul do Brasil: Habemus nucleos!]
Durante a pré-história, a debitagem laminar é um modo de produção característico de determinados períodos e regiões. No Brasil, no momento, foi reconhecida em três sítios arqueológicos situados no alto vale do rio Uruguai (SC/RS), em contextos sedimentares que datam do Holoceno inicial. Até hoje, somente os produtos dessa debitagem, as lâminas, tinham sido encontrados. A falta dos núcleos impedia um entendimento completo do processo de lascamento desses suportes. Graças à retomada das pesquisas na região desde 2013, foi possível coletar núcleos associados a essa produção laminar. Nesse artigo, descrevemos cinco desses núcleos. Suas análises demonstram que essa debitagem laminar corresponde a um único conceito. A estrutura volumétrica do núcleo que resulta desse conceito respeita as seguintes normas: 1) Os núcleos apresentam duas superfícies: um dorso plano e uma superfície de debitagem convexa mas relativamente achatada. Em uma extremidade, uma pequena superfície plana serviu de plano de percussão; 2) A debitagem começa por uma fase de inicialização durante a qual o plano de percussão é produzido por uma grande retirada. Em função das propriedades naturais do volume inicial, o dorso do núcleo é obtido, seja durante a seleção do bloco, seja por uma preparação por grandes retiradas transversais. Quando existem ainda, os negativos de retiradas da inicialização da superfície de debitagem indicam um método centrípeto; 3) As lâminas são sempre produzidas por um método unidirecional paralelo. A variabilidade desta debitagem é principalmente relacionada à técnica de lascamento: a percussão com pedra e a percussão com percutor orgânico foram utilizadas para a obtenção das lâminas. As informações tecnológicas fornecidas pelos núcleos aqui analisados são coerentes com essas observações oriundas da análise das lâminas. Com esses dois estudos consegue-se atingir um conhecimento completo desse sistema de produção do alto vale do rio Uruguai durante o Holoceno inicial, a única debitagem laminar documentada até hoje no Brasil.Blade debitage is a characteristic production pattern of specific periods and regions during Prehistory. In South America, it is well documented in Argentina, in contexts dating back to early Holocene. In Brazil, it was unknown until 2006, when it was found in three archaeological sites (ACH-LP-01, ACH-LP-03, ALP-AA-03) in the Foz do Chapecó area, upper Uruguay River, South Brazil, in layers from early Holocene. It was associated there with a great variety of other production systems: bifacial shaping of projectile points and large tools, unipolar debitage of large flakes, bipolar debitage of tiny flakes. Silicified sandstone, chalcedony and hyaline quartz are the main used raw materials. To this day, only the products of this debitage, the blades, had been discovered. Cores were lacking, which prevented a complete understanding of the flaking process. Due to the resumption of research in the region from 2013, it was possible to find those cores during surveys in the two following archaeological sites: ACH-LP-07 and RS-URG-01, located on both sides of the Uruguay river, near the mouth of the Chapecó river. We describe in this article five of these cores (4 from ACH-LP-07 and 1 from RS-URG-01). Their analyses demonstrate that this blade debitage complies with only one concept. The core volumetric structure that is the result of this concept displays the following features: 1) Cores have two surfaces: a flat back and a convex but relatively flattened flaking surface, so that they have a general “D” shaped transversal section. At one end, a small surface acts as striking platform during the production of the blades; 2) Debitage begins with a initialization phase of the core during which the striking platform is produced by a large removal. According to the natural properties of the initial volume, the back of the core is obtained either during the selection of the blank, and then it is left in his natural state, or by a preparation by one or more large transversal removals. When present, the scars of the initialization phase of the flaking surface indicate the use of a centripetal method. This preparation is made possible by the acute angle of the peripheral ridge formed by the intersection of the back and the flaking surface ; 3) Blades are always produced by a unidirectional parallel method. Production variability is mainly related to the flaking technique: both internal percussion by stone and marginal percussion by organic percussor were used to get the blades. Technical information provided by the cores are complementary and in accordance with those from the previous analyses of the blades from the same area. With these two studies it was possible to reach a relatively exhaustive understanding of this production system in the upper Uruguay River during early Holocene, the only well documented blade debitage in Brazil known until now. Future research will explore the interactions between this production and the other debitage and shaping methods inside this early Holocene technological system. To do this, we will develop a comprehensive study of all lithic artefacts from the archaeological layers in which blade production was identified. In a wider scale, a comparative approach with Argentinian and Uruguayan prehistoric blade productions will allow to better understand the development of the blade phenomenon in the southern cone of South America
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The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 9 Spectroscopic Galaxy Sample
We present measurements of galaxy clustering from the Baryon Oscillation
Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III
(SDSS-III). These use the Data Release 9 (DR9) CMASS sample, which contains
264,283 massive galaxies covering 3275 square degrees with an effective
redshift z=0.57 and redshift range 0.43 < z < 0.7. Assuming a concordance
Lambda-CDM cosmological model, this sample covers an effective volume of 2.2
Gpc^3, and represents the largest sample of the Universe ever surveyed at this
density, n = 3 x 10^-4 h^-3 Mpc^3. We measure the angle-averaged galaxy
correlation function and power spectrum, including density-field reconstruction
of the baryon acoustic oscillation (BAO) feature. The acoustic features are
detected at a significance of 5\sigma in both the correlation function and
power spectrum. Combining with the SDSS-II Luminous Red Galaxy Sample, the
detection significance increases to 6.7\sigma. Fitting for the position of the
acoustic features measures the distance to z=0.57 relative to the sound horizon
DV /rs = 13.67 +/- 0.22 at z=0.57. Assuming a fiducial sound horizon of 153.19
Mpc, which matches cosmic microwave background constraints, this corresponds to
a distance DV(z=0.57) = 2094 +/- 34 Mpc. At 1.7 per cent, this is the most
precise distance constraint ever obtained from a galaxy survey. We place this
result alongside previous BAO measurements in a cosmological distance ladder
and find excellent agreement with the current supernova measurements. We use
these distance measurements to constrain various cosmological models, finding
continuing support for a flat Universe with a cosmological constant.Comment: 33 page
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