242 research outputs found
Massive 70 micron quiet clumps I: evidence of embedded low/intermediate-mass star formation activity
Massive clumps, prior to the formation of any visible protostars, are the
best candidates to search for the elusive massive starless cores. In this work
we investigate the dust and gas properties of massive clumps selected to be 70
micron quiet, therefore good starless candidates. Our sample of 18 clumps has
masses 300 < M < 3000 M_sun, radius 0.54 < R < 1.00 pc, surface densities Sigma
> 0.05 g cm^-2 and luminosity/mass ratio L/M < 0.3. We show that half of these
70 micron quiet clumps embed faint 24 micron sources. Comparison with GLIMPSE
counterparts shows that 5 clumps embed young stars of intermediate stellar mass
up to ~5.5 M_sun. We study the clump dynamics with observations of N2H+ (1-0),
HNC (1-0) and HCO+ (1-0) made with the IRAM 30m telescope. Seven clumps have
blue-shifted spectra compatible with infall signatures, for which we estimate a
mass accretion rate 0.04 < M_dot < 2.0 x 10^-3 M_sun yr^-1, comparable with
values found in high-mass protostellar regions, and free-fall time of the order
of t_ff = 3 x 10^5 yr. The only appreciable difference we find between objects
with and without embedded 24 micron sources is that the infall rate appears to
increase from 24 micron dark to 24 micron bright objects. We conclude that all
70 micron quiet objects have similar properties on clump scales, independently
of the presence of an embedded protostar. Based on our data we speculate that
the majority, if not all of these clumps may already embed faint, low-mass
protostellar cores. If these clumps are to form massive stars, this must occur
after the formation of these lower mass stars.Comment: 44 pages, 11 Figures. Accepted for publication in MNRA
Usefulness of Heart Rate Variability to Identify the Risk of Falling in Huntington’s Disease
Objective: To evaluate the relationship between the HRV and the risk of falling in HD patients.Background: Huntington’s disease (HD) patients have a high prevalence of falls, on the other hand, autonomic nervous system dysfunction has been reported from early stages of the disease. However, there is lack of evidence regarding the relationship between heart rate variability (HRV) and falls in this population....Fil: Terroba Chambi, Cinthia Jennifer. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vigo, Daniel E.. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Merello, Marcelo Jorge. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaInternational Congress of the Parkinson's Disease and Movement DisordersNizaFranciaInternational Parkinson and Movement Disorder Societ
SiO Outflows in the Most Luminous and Massive Protostellar Sources of the Southern Sky
(Abridged) High-mass star formation is far less understood than low-mass star
formation. It entails molecular outflows, which disturb the protostellar clump.
Studying these outflows and the shocked gas they cause is key for a better
understanding of this process. This study aims to characterise the behaviour of
molecular outflows in the most massive protostellar sources in the Southern
Galaxy by looking for evolutionary trends and associating shocked gas with
outflow activity. We present APEX SEPIA180 observations (beamwidth 36")
of SiO outflow candidates of a sample of 32 luminous and dense clumps,
candidates to harbouring Hot Molecular Cores. We study the SiO(4-3) line
emission, an unambiguous tracer of shocked gas and recent outflow activity, the
HCO(2-1) and HCO(2-1) lines. 78% of our sample present SiO
emission. Nine of these also have wings in the HCO line, indicating outflow
activity. The SiO emission of these 9 sources is more intense and wider than
the rest, suggesting that the outflows in this group are faster and more
energetic. Three positive correlations between the outflow properties were
found, which suggest that more energetic outflows bear to mobilise more
material. No correlation was found between the evolutionary stage indicator
and SiO outflow properties, supporting that outflows happen throughout
the whole high-mass star formation process. We conclude that sources with both
SiO emission and HCO wings and sources with only SiO emission are in
virtually the same advanced stage of evolution in the high-mass star formation
process. The former present more massive and more powerful SiO outflows than
the latter. Thus, looking for more outflow signatures such as HCO wings
could help identify more massive and active massive star-forming regions in
samples of similarly evolved sources, as well as sources with older outflow
activity.Comment: 24 pages, 37 figures, 11 table
A framework for the evaluation of educational development programs in higher education in Chile
[EN] This paper outlines the experience of evaluating the impact of educational development in Chilean higher education drawing on the example of the Universidad Católica de Temuco. The aim is to demonstrate the importance of a implementing a robust and flexible evaluation and impact framework to identify the effectiveness of education development programs. The rationale and processes that informed the development of the evaluation and impact framework are described and then illustrated with one example, the Faculty Learning Communities (FLC) program. The example shows how the overall framework is contextualised in a specific program, drawing on indicators and outcomes to demonstrate its flexibility and robustness. The rich evidence gathered has been used to inform the educational developers on the effectiveness of their work, and the faculty participants on their knowledge and practice. Just as importantly, it has informed the institution about the impact of the programs and student engagement. The evaluation framework provides a Chilean example informed by international best practice.http://ocs.editorial.upv.es/index.php/HEAD/HEAD18Moya, B.; Turra, H.; Chalmers, D. (2018). A framework for the evaluation of educational development programs in higher education in Chile. Editorial Universitat Politècnica de València. 365-372. https://doi.org/10.4995/HEAD18.2018.7997OCS36537
Cost effective assay choice for rare disease study designs
High throughput assays tend to be expensive per subject. Often studies are limited not so much by the number of subjects available as by assay costs, making assay choice a critical issue. We have developed a framework for assay choice that maximises the number of true disease causing mechanisms ‘seen’, given limited resources. Although straightforward, some of the ramifications of our methodology run counter to received wisdom on study design. We illustrate our methodology with examples, and have built a website allowing calculation of quantities of interest to those designing rare disease studies.published_or_final_versio
Characterisation of thermo-hygrometric conditions of an archaeological site affected by unlike boundary weather conditions
This paper applies statistical techniques to analyse microclimatic data (temperature and relative humidity) recorded at the archaeological site of Plaza de l'Almoina (Valencia, Spain). This study has allowed us to quantify the effect of certain measures that were adopted for preventive conservation. The first monitoring campaign took place in 2010 at this archaeological site, showing harmful effects on the conservation state of the remains due to the presence of a skylight that partly covers the remains and causes a greenhouse effect. This skylight was covered with a water layer to prevent overheating of this archaeological site. However, this layer was removed in 2013 due to water leaks, and the indoor conditions changed. Over the summer, a temporary canvas was installed over the skylight to avoid heating of the archaeological site below by preventing the incidence of direct sunlight. The main importance of this work was to characterise the effect of unlike boundary weather conditions of different years in the indoor microclimate of the archaeological site, and to study the effect of the new boundary situation. This paper shows that the removal of water from the skylight caused a temperature increase inside the museum; meanwhile, the subsequent installation of the canvas cover allows appropriate daily cycles of temperature and relative humidity, especially in areas under the skylight. This work also shows that the replacement of a water ditch near the archaeological site by a PVC pipe was also detected by the sensors due to the difference in water vapour pressure.This work was partially supported by the Spanish Government (Ministerio de Ciencia e Innovacion) with grants numbers HAR2010-21944-C02-01 and HAR2010-21944-C02-02. The authors thank the personal collaboration of the archaeologist Albert Ribera and Carmen Perez.Merello Gimenez, P.; Fernández Navajas, A.; Curiel Esparza, J.; Zarzo Castelló, M.; García Diego, FJ. (2014). Characterisation of thermo-hygrometric conditions of an archaeological site affected by unlike boundary weather conditions. Building and Environment. 76:125-133. doi:10.1016/j.buildenv.2014.03.009S1251337
Correlação entre 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET em pacientes com doença de Parkinson: Um estudo piloto
Objective: To determine whether technetium-99m-labeled tropane derivative single-photon emission computed tomography (99mTc-TRODAT-1 SPECT) provides results comparable to those of the less widely available, less accessible tool fluorine-18-labeled fluorodopa positron-emission tomography (18F-FDOPA PET) in the setting of a movement disorders clinic. Materials and Methods: In this prospective pilot study, eight subjects with a clinical diagnosis of Parkinson’s disease were randomly selected from among patients under treatment at a movement disorders clinic and submitted to99mTc-TRODAT-1 SPECT and18F-FDOPA PET. The results were read by two experienced observers, and a semiquantitative analysis was performed. Results: The visual and semiquantitative analyses were concordant for all studies, showing that radiotracer uptake in the contralateral striatum on the most affected side was lower when99mTc-TRODAT-1 SPECT was employed. The semiquantitative analysis demonstrated a significant correlation between18F-FDOPA PET and99mTc-TRODAT-1 SPECT (r = 0.73; p < 0.01). Conclusion: It appears that99mTc-TRODAT-1 SPECT is a valid option for the study of dopaminergic function in a clinical setting.Objetivo: Determinar se a 99mTc-TRODAT-1 SPECT fornece resultados comparáveis aos da 18F-FDOPA PET, ferramenta menos acessível e menos amplamente disponível, no contexto de uma clínica de distúrbios do movimento. Materiais e Métodos: Neste estudo prospectivo, oito indivíduos com diagnóstico clínico de doença de Parkinson foram selecionados aleatoriamente entre pacientes em tratamento em uma clínica de distúrbios do movimento e submetidos a 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET. Os resultados foram lidos por dois observadores experientes e uma análise semiquantitativa foi realizada. Resultados: As análises visual e semiquantitativa foram concordantes para todos os estudos, mostrando que a captação do radiotraçador no estriado contralateral do lado mais afetado foi menor quando a 99mTc-TRODAT-1 SPECT foi empregada. A análise semiquantitativa demonstrou uma correlação significativa entre 18F-FDOPA PET e 99mTc-TRODAT-1 SPECT (r = 0,73; p < 0,01). Conclusão: A 99mTc-TRODAT-1 SPECT parece ser uma opção válida para o estudo da função dopaminérgica em um ambiente clínico.Fil: Arena, Julieta E.. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Urrutia, Leandro. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Falasco, Germán Alfredo. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Ponce de Leon, Magdalena. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Vazquez, Silvia. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Rossi, Malco Damian. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Merello, Marcelo Jorge. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia. Instituto de Neurociencias - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Neurociencias; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; Argentin
Testing Larson's relationships in massive clumps
We tested the validity of the three Larson relations in a sample of 213
massive clumps selected from the Herschel Hi-GAL survey and combined with data
from the MALT90 survey of 3mm emission lines. The clumps have been divided in 5
evolutionary stages to discuss the Larson relations also as function of
evolution. We show that this ensemble does not follow the three Larson
relations, regardless of clump evolutionary phase. A consequence of this
breakdown is that the virial parameter dependence with mass (and
radius) is only a function of the gravitational energy, independent of the
kinetic energy of the system, and is not a good descriptor of
clump dynamics. Our results suggest that clumps with clear signatures of infall
motions are statistically indistinguishable from clumps with no such
signatures. The observed non-thermal motions are not necessarily ascribed to
turbulence acting to sustain the gravity, but they may be due to the
gravitational collapse at the clump scales. This seems particularly true for
the most massive (M1000 M) clumps in the sample, where also
exceptionally high magnetic fields may not be enough to stabilize the collapse.Comment: Accepted for publication in MNRA
Thermal balance and comparison of gas and dust properties of dense clumps in the Hi-GAL survey
We present a comparative study of physical properties derived from gas and dust emission in a sample of 1068 dense Galactic clumps. The sources are selected from the cross-match of the Herschel Infrared Galactic Plane Survey with 16 catalogues of NH3 line emission in its lowest inversion (1,1) and (2,2) transitions. The sample covers a large range in masses and bolometric luminosities, with surface densities above Sigma = 0.1 g cm(-2) and with low virial parameters alpha < 1. The comparison between dust and gas properties shows an overall agreement between T-kin and T-dust at volumetric densities n greater than or similar to 1.2 x 10(4)cm(-3), and a median fractional abundance chi (NH3) = 1.46 x 10(-8). While the protostellar clumps in the sample have small differences between T-kin and T-dust, prestellar clumps have a median ratio T-kin/T-dust = 1.24, suggesting that these sources are thermally decoupled. A correlation is found between the evolutionary tracer L/M and the parameters T-kin/T-dust and chi(NH3) in prestellar sources and protostellar clumps with L/M < 1 L circle dot M circle dot-1 . In addition, a weak correlation is found between non-thermal velocity dispersion and the L/M parameter, possibly indicating an increase of turbulence with protostellar evolution in the interior of clumps. Finally, different processes are discussed to explain the differences between gas and dust temperatures in prestellar candidates, and the origin of non-thermal motions observed in the clumps.Sao Paulo Research Foundation (FAPESP) [2017/23708-0]; Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA [CUP C52I13000140001]; European Union [607380]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
The Hi-GAL compact source catalogue - II. The 360° catalogue of clump physical properties
We present the 360° catalogue of physical properties of Hi-GAL compact sources, detected between 70 and 500 μm. This release not only completes the analogous catalogue previously produced by the Hi-GAL collaboration for -71° ≲ ℓ ≲ 67°, but also meaningfully improves it because of a new set of heliocentric distances, 120 808 in total. About a third of the 150 223 entries are located in the newly added portion of the Galactic plane. A first classification based on detection at 70 μm as a signature of ongoing star-forming activity distinguishes between protostellar sources (23 per cent of the total) and starless sources, with the latter further classified as gravitationally bound (pre-stellar) or unbound. The integral of the spectral energy distribution, including ancillary photometry from λ = 21 to 1100 μm, gives the source luminosity and other bolometric quantities, while a modified blackbody fitted to data for λ ≥ 160μm yields mass and temperature. All tabulated clump properties are then derived using photometry and heliocentric distance, where possible. Statistics of these quantities are discussed with respect to both source Galactic location and evolutionary stage. No strong differences in the distributions of evolutionary indicators are found between the inner and outer Galaxy. However, masses and densities in the inner Galaxy are on average significantly larger, resulting in a higher number of clumps that are candidates to host massive star formation. Median behaviour of distance-independent parameters tracing source evolutionary status is examined as a function of the Galactocentric radius, showing no clear evidence of correlation with spiral arm positions
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