3,997 research outputs found
Contemporary perspective on addictive behaviors: underpinning mechanisms, assessment, and treatment
This special issue gathered contributions from authors in the scientifc community working on addictive behaviors. In particular, authors were solicited to relate about underpinning mechanisms, assessment protocols, and intervention programs that are currently proposed for substance abuse,
Internet addiction, and other forms of problematic conducts in pediatric populations, adolescence, and adulthood. Most of the papers used a biopsychosocial model for the onset and maintaining of addictive behaviors and their comorbidities with other psychopathologies. Although the intent was accept
contributions focused on all forms of addictive behaviors, this special issue is composed of four papers concerning problematic use of the web and two articles focusing on substance use. Of note, all papers addressed the developmental phases of childhood and adolescence
Coarse graining of master equations with fast and slow states
We propose a general method for simplifying master equations by eliminating
from the description rapidly evolving states. The physical recipe we impose is
the suppression of these states and a renormalization of the rates of all the
surviving states. In some cases, this decimation procedure can be analytically
carried out and is consistent with other analytical approaches, like in the
problem of the random walk in a double-well potential. We discuss the
application of our method to nontrivial examples: diffusion in a lattice with
defects and a model of an enzymatic reaction outside the steady state regime.Comment: 9 pages, 9 figures, final version (new subsection and many minor
improvements
On the time delay in binary systems
The aim of this paper is to study the time delay on electromagnetic signals
propagating across a binary stellar system. We focus on the antisymmetric
gravitomagnetic contribution due to the angular momentum of one of the stars of
the pair. Considering a pulsar as the source of the signals, the effect would
be manifest both in the arrival times of the pulses and in the frequency shift
of their Fourier spectra. We derive the appropriate formulas and we discuss the
influence of different configurations on the observability of gravitomagnetic
effects. We argue that the recently discovered PSR J0737-3039 binary system
does not permit the detection of the effects because of the large size of the
eclipsed region.Comment: 7 pages, 2 eps figures, RevTex, to appear in Physical Review
Geodiversity of Ceará State (Brazil): assessment and mapping
The results on the geodiversity assessment of Ceará State (148,016 km2, northeast Brazil) are presented. The
assessment was performed using a methodology based on the counting of occurrences of geodiversity with cartographical
data and GIS procedures. This work is part of the methodological approaches applied in other large
territories in Brazil and Portugal considering geodiversity as the diversity of rocks, fossils, lanforms, soils, water
resources, and mineral and energy sources occurrences. Therefore, the geodiversity index resulted from the sum of
the six partial indices: i) lithological; ii) paleontological; iii) geomorphological; iv) pedological; vi) hydrological;
vi) mineral occurrences. The Geodiversity Index score of each grid square is the sum of all partial indices. Hydrological
partial index was an upgrade to the previous five-partial indices methodological proposal, considering both
surface water resources and ground water as essential components of geodiversity. Furthermore, the traditional cell
grid used to operate the counting of geodiversity elements was substituted by a territorial organization by drainage
sub-basins. Vector cartographical data were obtained from official Brazilian institutions and treated with GIS software
to generate the six partial indices. According to the type of occurences these indices may have very different
ranges thus values were normalized to a maximum of 5 points each. The sum of partial indices in each drainage
sub-basin resulted in a quantitative map of geodiversity with values from 4 to 26. Subsequently the values were
interpolated using the Kriging method delivering the geodiversity map of the Ceará State. Geodiversity index was
here defined with qualitative values ranging from “very low” to “very high”. The regions Noroeste Cearense and
Sul Cearense have the highest geodiversity in the state while the region Sertões Cearenses has the lowest. The use
of specific GIS procedures increases the mapping options and confirmed that they can speed-up spatial analysis to
calculate geodiversity if official digital maps are available.info:eu-repo/semantics/publishedVersio
Assessment of water resources potential of Ceará state (Brazil)
A methodological approach and results on water resources assessment in large areas are described with the case
study of Ceará State (148,016 km2, northeast Brazil), where the scarceness of water resources is one of the main
challenges in territorial planning and development. This work deals with the quantification and the mapping of
water resources potential, being part of methodological approaches applied to the quantification of hydric diversity
and geodiversity. Water resources potential is here considered as the sum of the hydric elements rainfall, groundwater
specific discharge, water reservoirs, and river hierarchy. The assessment was based in a territorial organization
by drainage sub-basins and in vector maps generated and treated with GIS software. Rainfall, groundwater specific
discharge and hydrographical data were obtained in official institutions and allowed the construction of the annual
mean rainfall map for a forty year period (1974-2014), the annual mean groundwater specific discharge map for
a thirty-four year period, and the river and drainage basin hierarchy maps. These delivered rainfall, groundwater
specific discharge, water reservoirs and river hierarchy partial indices expressed on quantitative maps with normalized
values distributed by level 3 drainage basins. The sum of the partial indices originated the quantitative
map of water resources potential index and by the Gaussian interpolation of this quantitative data a map of hydric
diversity in Ceará state was created. Therefore, the water resources potential index is higher in 4 regions of the state
(Noroeste Cearense, Zona Metropolitana de Fortaleza e da Zona Norte, Vale do Jaguaribe and Zonas Centro-sul
e Sul Cearense). The index is low or very low in the whole region of Sertões Cearenses, confirming the important
role of climatic features in hydrological diversity. Water resources management must consider technical tools
for water resources assessment, in the line of other methods for quantitative assessment of natural features either
biotic or abiotic. These results quantify water resources and their distribution in a large region with important climatic
differences. They constitute a basis for the knowledge of regional issues concerning water needs, flood and
droughts events and even engineering solutions for water resources management.info:eu-repo/semantics/publishedVersio
Perinatal outcomes of frequent attendance in midwifery care in the Netherlands: a retrospective cohort study
Background Over the last decade, a trend towards high utilisation of primary maternity care was observed in high-income countries. There is limited research with contradictory results regarding frequent attendance (FA) and perinatal outcomes in midwifery care. Therefore, this study examined possible associations between FA in midwifery care and obstetric interventions and perinatal outcomes. Methods A retrospective cohort study was performed in a medium-sized midwifery-led care practice in an urban region in the Netherlands. Frequent attenders (FAs) were categorised using the Kotelchuck-Index Revised. Regression analyses were executed to examine the relationship between FAs and perinatal outcomes, stratified by antenatal referral to an obstetrician. Main outcomes of interest were Apgar score ≤ 7 and perinatal death, birth weight, mode of delivery, haemorrhage, place of birth, transfer during labour, and a requirement for pain relief. Results The study included 1015 women, 239 (24%) FAs and 776 (76%) non-FAs, 538 (53%) were not referred and 447 (47%) were referred to an obstetrician. In the non-referred group, FA was significantly associated with a requirement for pain relief (OR 1.98, 95% CI 1.24–3.17) and duration of dilatation (OR 1.20, 95% CI 1.04–1.38). In the referred group, FA was significantly associated with induction of labour (OR 1.86, 95% CI 1.17–2.95), ruptured perineum (OR 0.50, 95% CI 0.27–0.95) and episiotomy (OR 0.48, 95% CI 0.24–0.95). In the non-referred and the referred group, FA was not associated with the other obstetric and neonatal outcomes. Due to small numbers, we could not measure possible associations of FA with an Apgar score ≤ 7 and perinatal death. Conclusion In our study, perinatal outcomes differed by FA and antenatal referral to an obstetrician. In the non-referred group, FA was significantly associated with medical pain relief and duration of dilatation. In the referred group, FA was significantly associated with induction of labour, ruptured perineum, and episiotomy. Further research with a larger study population is needed to look for a possible association between FA and primary adverse birth outcomes such as perinatal mortality
The quantum theory of measurement within dynamical reduction models
We analyze in mathematical detail, within the framework of the QMUPL model of
spontaneous wave function collapse, the von Neumann measurement scheme for the
measurement of a 1/2 spin particle. We prove that, according to the equation of
the model: i) throughout the whole measurement process, the pointer of the
measuring device is always perfectly well localized in space; ii) the
probabilities for the possible outcomes are distributed in agreement with the
Born probability rule; iii) at the end of the measurement the state of the
microscopic system has collapsed to the eigenstate corresponding to the
measured eigenvalue. This analysis shows rigorously how dynamical reduction
models provide a consistent solution to the measurement problem of quantum
mechanics.Comment: 24 pages, RevTeX. Minor changes mad
Evaluation of the integration of the Wind-Induced Flutter Energy Harvester (WIFEH) into the built environment: experimental and numerical analysis
With the ubiquity of low-powered technologies and devices in the urban environment operating in every area of human activity, the development and integration of a low-energy harvester suitable for smart cities applications is indispensable. The multitude of low-energy applications extend from wireless sensors, data loggers, transmitters and other small-scale electronics. These devices function in the microWatt-milliWatt power range and will play a significant role in the future of smart cities providing power for extended operation with little or no battery dependence. This study thus aims to investigate the potential built environment integration and energy harvesting capabilities of the Wind-Induced Flutter Energy Harvester (WIFEH) – a microgenerator aimed to provide energy for low-powered applications. Low-energy harvesters such as the WIFEH are suitable for integration with wireless sensors and other small-scale electronic devices; however, there is a lack in study on this type of technology’s building integration capabilities. Hence, there is a need for investigating its potential and optimal installation conditions.
This work presents the experimental investigation of the WIFEH inside a wind tunnel and a case study using Computational Fluid Dynamics (CFD) modelling of a building integrated with a WIFEH system. The experiments tested the WIFEH under various wind tunnel airflow speeds ranging from 2.3 to 10 m/s to evaluate the induced electromotive force generation capability of the device. The simulation used a gable-roof type building model with a 27° pitch obtained from the literature. The atmospheric boundary layer (ABL) flow was used for the simulation of the approach wind. The work investigates the effect of various wind speeds and WIFEH locations on the performance of the device giving insight on the potential for integration of the harvester into the built environment. The WIFEH was able to generate an RMS voltage of 3 V, peak-to-peak voltage of 8.72 V and short-circuit current of 1 mA when subjected to airflow of 2.3 m/s. With an increase of wind velocity to 5 m/s and subsequent membrane retensioning, the RMS and peak-to-peak voltages and short-circuit current also increase to 4.88 V, 18.2 V, and 3.75 mA, respectively. For the CFD modelling integrating the WIFEH into a building, the apex of the roof of the building yielded the highest power output for the device due to flow speed-up maximisation in this region. This location produced the largest power output under the 45° angle of approach, generating an estimated 62.4 mW of power under accelerated wind in device position of up to 6.2 m/s. For wind velocity (UH) of 10 m/s, wind in this position accelerated up to approximately 14.4 m/s which is a 37.5% speed-up at the particular height. This occurred for an oncoming wind 30° relative to the building facade. For UH equal to 4.7 m/s under 0° wind direction, airflows in facade edges were the fastest at 5.4 m/s indicating a 15% speed-up along the edges of the building
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