1,642 research outputs found
Experimental phase functions of mm-sized cosmic dust grains
We present experimental phase functions of three types of millimeter-sized
dust grains consisting of enstatite, quartz and volcanic material from Mount
Etna, respectively. The three grains present similar sizes but different
absorbing properties. The measurements are performed at 527 nm covering the
scattering angle range from 3 to 170 degrees. The measured phase functions show
two well defined regions i) soft forward peaks and ii) a continuous increase
with the scattering angle at side- and back-scattering regions. This behavior
at side- and back-scattering regions are in agreement with the observed phase
functions for the Fomalhaut and HR 4796A dust rings. Further computations and
measurements (including polarization) for millimeter sized-grains are needed to
draw some conclusions about the fluffy or compact structure of the dust grains
Additional Physical Interventions to Conventional Physical Therapy in Parkinson’s Disease: A Systematic Review and Meta-Analysis of Randomized Clinical Trials
Parkinson's disease (PD) represents the second most common neurodegenerative disease. Currently, conventional physical therapy is complemented by additional physical interventions with recreational components, improving different motor conditions in people with PD. This review aims to evaluate the effectiveness of additional physical interventions to conventional physical therapy in Parkinson's disease. A systematic review and meta-analysis of randomized controlled trials were performed. The literature search was conducted in PubMed, Physiotherapy Evidence Database (PEDro), Scopus, SciELO and Web of Science. The PEDro scale was used to evaluate the methodological quality of the studies. A total of 11 randomized controlled trials were included in this review. Five of them contributed information to the meta-analysis. The statistical analysis showed favorable results for dance-based therapy in motor balance: (Timed Up and Go: standardized mean difference (SMD) = −1.16; 95% Confidence Interval (CI):(−2.30 to −0.03); Berg Balance Scale: SMD = 4.05; 95%CI:(1.34 to 6.75)). Aquatic interventions showed favorable results in balance confidence (Activities-Specific Balance Confidence: SMD=10.10; 95%CI:(2.27 to 17.93)). The results obtained in this review highlight the potential benefit of dance-based therapy in functional balance for people with Parkinson's disease, recommending its incorporation in clinical practice. Nonetheless, many aspects require clarification through further research and high-quality studies on this subject
Small-scale magnetic flux emergence in the quiet Sun
Small bipolar magnetic features are observed to appear in the interior of
individual granules in the quiet Sun, signaling the emergence of tiny magnetic
loops from the solar interior. We study the origin of those features as part of
the magnetoconvection process in the top layers of the convection zone. Two
quiet-Sun magnetoconvection models, calculated with the
radiation-magnetohydrodynamic (MHD) Bifrost code and with domain stretching
from the top layers of the convection zone to the corona, are analyzed. Using
3D visualization as well as a posteriori spectral synthesis of Stokes
parameters, we detect the repeated emergence of small magnetic elements in the
interior of granules, as in the observations. Additionally, we identify the
formation of organized horizontal magnetic sheets covering whole granules. Our
approach is twofold, calculating statistical properties of the system, like
joint probability density functions (JPDFs), and pursuing individual events via
visualization tools. We conclude that the small magnetic loops surfacing within
individual granules in the observations may originate from sites at or near the
downflows in the granular and mesogranular levels, probably in the first 1 or
1.5 Mm below the surface. We also document the creation of granule-covering
magnetic sheet-like structures through the sideways expansion of a small
subphotospheric magnetic concentration picked up, and pulled out of the
interior, by a nascent granule. The sheet-like structures we found in the
models may match the recent observations of Centeno et al. (2017).Comment: 9 pages, 5 figures, Published in The Astrophysical Journal Letter
Power Quality Monitoring Integration into Distribution Automation through the Use of AMR
Power-quality events are of increasing concern for the
economy because today’s equipment, particularly computers and
automated manufacturing devices, is highly sensitive to such
imperfections. With volatile energy rates and a need to control
costs, regional agencies and utilities are interested in technologies
to meter distribution use and manage utility information.
Metering technologies and communications systems have
advanced to enable the development of Automated Meter Reading
(AMR) Systems. Power Quality is one area where the AMR
system can be very valuable. This paper investigates the
challenges in the development of distributed power-quality
monitoring system. The approach of this paper is divided into
metering, data collection, archiving, analysis, and presentation. It
also discusses system architecture, implementation, and provides
general guidelines in the tailoring of PQ indexes. This paper
describes the challenges and lessons learned from this work.
Morfología de las ciudades silentes de Cartagena. Reflejos del urbanismo de la ciudad viva
La aspiración humana de ir más allá de la vida ha ocasionado diversas manifestaciones de grandeza
que en ocasiones se han visto reflejadas en los lugares elegidos para alojar sus restos tras el momento
final. Desde que en el s.XIX Cartagena acatara las disposiciones de la Real Cédula de Carlos
III por la que se imponía emplazar los recintos funerarios extramuros de las ciudades, se establecieron
en la misma dos cementerios que aún hoy siguen funcionando; el cementerio de San Antonio
Abad (1806) y el de Nuestra Señora de los Remedios (1868).
Esta comunicación pretende analizar las distintas morfologías urbanas ensayadas en estos camposantos
para mostrar la diferente concepción de los dos espacios y el reflejo en la ciudad viva de los
modelos urbanos con que fueron concebidas ambas ciudades silentes. El primero, imitó modelos
racionales como el que Ferdinando Fuga había practicado en Italia, donde bajo ideales ilustrados;
vivos y muertos serían igualados en el momento final, y el segundo fue proyectado como un cementerio
romántico en el que los hombres ilustres de la Cartagena decimonónica construyeron sus
panteones a imagen de las mansiones emplazadas en la otra ciudad
WEB MAPPING ARCHITECTURES BASED ON OPEN SPECIFICATIONS AND FREE AND OPEN SOURCE SOFTWARE IN THE WATER DOMAIN
The availability of water-related data and information across different geographical and jurisdictional scales is of critical importance for the conservation and management of water resources in the 21st century. Today information assets are often found fragmented across multiple agencies that use incompatible data formats and procedures for data collection, storage, maintenance, analysis, and distribution. The growing adoption of Web mapping systems in the water domain is reducing the gap between data availability and its practical use and accessibility. Nevertheless, more attention must be given to the design and development of these systems to achieve high levels of interoperability and usability while fulfilling different end user informational needs. This paper first presents a brief overview of technologies used in the water domain, and then presents three examples of Web mapping architectures based on free and open source software (FOSS) and the use of open specifications (OS) that address different users' needs for data sharing, visualization, manipulation, scenario simulations, and map production. The purpose of the paper is to illustrate how the latest developments in OS for geospatial and water-related data collection, storage, and sharing, combined with the use of mature FOSS projects facilitate the creation of sophisticated interoperable Web-based information systems in the water domain
Highly photostable solid-state dye lasers based on silicon-modified organic matrices
11 pages, 13 figures, 4 tables.-- PACS: 42.55.Rz; 42.60.FcWe report on the synthesis, characterization, and physical properties of modified polymeric matrices incorporating silicon atoms in their structure and doped with laser dyes. When the silicon-modified organic matrices incorporated pyrromethene 567 (PM567) and pyrromethene 597 (PM597) dyes as actual solid solutions, highly photostable laser operation with reasonable, nonoptimized efficiencies was obtained under transversal pumping at 532 nm. At a pump repetition rate of 10 Hz, the intensity of the laser emission remained at the level or above the initial lasing intensity after 100 000 pump pulses in the same position of the sample, corresponding to an estimated accumulated pump energy absorbed by the system of 518 and 1295 GJ/mol for PM567 and PM597, respectively. When the pump repetition rate was increased to 30 Hz, the laser emission of dye PM567 decreased steadily and the output energy fell to one-half its initial value after an accumulated pump energy of 989 GJ/mol. Dye PM597 demonstrated a remarkable photostability, and under 30 Hz pumping the laser emission from some samples remained stable after 700 000 pump pulses in the same position of the sample, corresponding to an accumulated pump energy of 17 300 GJ/mol. Narrow linewidth operation with tuning ranges of up to 31 nm was obtained with both pyrromethene dyes when some of the samples were incorporated into a grazing-incidence grating oscillator.This work was supported by Project Nos. 7N/0100/02 of
the Comunidad Autónoma de Madrid ( CAM) and MAT2004-
04643-C03-01 of the Spanish CICYT. One of the authors
(O.G.) thanks the MEC for awarding her a Ramón y Cajal
scientific contract. Another author (D.A.) thanks CAM for
a predoctoral scholarship.Peer reviewe
Zircon to monazite phase transition in CeVO4
X-ray diffraction and Raman-scattering measurements on cerium vanadate have
been performed up to 12 and 16 GPa, respectively. Experiments reveal that at
5.3 GPa the onset of a pressure-induced irreversible phase transition from the
zircon to the monazite structure. Beyond this pressure, diffraction peaks and
Raman-active modes of the monazite phase are measured. The zircon to monazite
transition in CeVO4 is distinctive among the other rare-earth orthovanadates.
We also observed softening of external translational Eg and internal B2g
bending modes. We attributed it to mechanical instabilities of zircon phase
against the pressure-induced distortion. We additionally report
lattice-dynamical and total-energy calculations which are in agreement with the
experimental results. Finally, the effect of non-hydrostatic stresses on the
structural sequence is studied and the equations of state of different phases
are reported.Comment: 45 pages, 8 figures, 8 table
Structural Brain Network Reorganization and Social Cognition Related to Adverse Perinatal Condition from Infancy to Early Adolescence.
Adverse conditions during fetal life have been associated to both structural and functional changes in neurodevelopment from the neonatal period to adolescence. In this study, connectomics was used to assess the evolution of brain networks from infancy to early adolescence. Brain network reorganization over time in subjects who had suffered adverse perinatal conditions is characterized and related to neurodevelopment and cognition. Three cohorts of prematurely born infants and children (between 28 and 35 weeks of gestational age), including individuals with a birth weight appropriated for gestational age and with intrauterine growth restriction (IUGR), were evaluated at 1, 6, and 10 years of age, respectively. A common developmental trajectory of brain networks was identified in both control and IUGR groups: network efficiencies of the fractional anisotropy (FA)-weighted and normalized connectomes increase with age, which can be related to maturation and myelination of fiber connections while the number of connections decreases, which can be associated to an axonal pruning process and reorganization. Comparing subjects with or without IUGR, a similar pattern of network differences between groups was observed in the three developmental stages, mainly characterized by IUGR group having reduced brain network efficiencies in binary and FA-weighted connectomes and increased efficiencies in the connectome normalized by its total connection strength (FA). Associations between brain networks and neurobehavioral impairments were also evaluated showing a relationship between different network metrics and specific social cognition-related scores, as well as a higher risk of inattention/hyperactivity and/or executive functional disorders in IUGR children
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