624 research outputs found
Assessment of surface currents measured with high-frequency phased-array radars in two regions of complex circulation
Surface velocity data from two WERA high frequency (HF) ocean radar systems, deployed as
part of the Australian Integrated Marine Observing System (IMOS), are compared with near surface
currents obtained from drifters and ADCPs (acoustic Doppler current profiler). We evaluate data from two
contrasting locations in the first detailed evaluation of the IMOS HF radar surface velocities. HF radar
measurements are generally robust but demand quality-control procedures to eliminate obvious errors and
outliers that appear temporarily or systematically in the data. A number of different quality control
procedures and filters are applied and assessed including Taylor diagrams, Hampel and Savitzky-Golay
filters. In addition the need for and effect of averaging are discussed. The radar measurements of surface
current agreed better with the near-surface drifter currents than with the subsurface ADCP currents.
Nonetheless the ADCP comparisons are consistent with those previously reported in other regions. The
value of the Taylor Diagram for comparing different surface current data sets and processing approaches is
demonstrated. Noise levels in the radar current spectra are used to estimate the error in the measurements
and in some cases, these errors were found to approach the precision of the radar estimates. Our results give
guidance on the most useful temporal sampling resolution. In particular we show that, at these sites and
these operating frequencies, using 10-minute sampling without further averaging does not provide
additional information because the higher frequencies are dominated by noise. Averaging the radials over
30-minutes may be sufficient for many applications
Assessment of surface currents measured with high-frequency phased-array radars in two regions of complex circulation
Surface velocity data from two WERA high frequency (HF) ocean radar systems, deployed as
part of the Australian Integrated Marine Observing System (IMOS), are compared with near surface
currents obtained from drifters and ADCPs (acoustic Doppler current profiler). We evaluate data from two
contrasting locations in the first detailed evaluation of the IMOS HF radar surface velocities. HF radar
measurements are generally robust but demand quality-control procedures to eliminate obvious errors and
outliers that appear temporarily or systematically in the data. A number of different quality control
procedures and filters are applied and assessed including Taylor diagrams, Hampel and Savitzky-Golay
filters. In addition the need for and effect of averaging are discussed. The radar measurements of surface
current agreed better with the near-surface drifter currents than with the subsurface ADCP currents.
Nonetheless the ADCP comparisons are consistent with those previously reported in other regions. The
value of the Taylor Diagram for comparing different surface current data sets and processing approaches is
demonstrated. Noise levels in the radar current spectra are used to estimate the error in the measurements
and in some cases, these errors were found to approach the precision of the radar estimates. Our results give
guidance on the most useful temporal sampling resolution. In particular we show that, at these sites and
these operating frequencies, using 10-minute sampling without further averaging does not provide
additional information because the higher frequencies are dominated by noise. Averaging the radials over
30-minutes may be sufficient for many applications
Avances en la agenda urbana : Santa Cruz de la Sierra
Este libro tiene como objetivo principal, presentar algunos trabajos del SINPA que
contribuyeron y representan “Avances en la Gestión Urbana”.
Estos artículos son fruto de la experiencia del proyecto SINPA como aporte a los cambios
y procesos de fortalecimiento de la gestión urbana en el Municipio de Santa Cruz de la
Sierra. La experiencia y lecciones aprendidas en estos últimos tres años, son
extremadamente actuales en el año en que la comunidad internacional se reunió para
evaluar la experiencia urbana de HABITAT+5, cinco años después de la II Conferencia
de las Naciones Unidas para los Asentamientos Humanos (Hábitat II, Estambul 1996)
(UNCHS, 1997). Uno de los puntos clave de las recomendaciones de esta Conferencia
fue la necesidad de que los gobiernos locales establezcan asociaciones con
organizaciones de la sociedad civil, en los procesos de planificación y gestión urbana.
Otra línea directriz de Hábitat II fue la profundización de políticas sostenibles de desarrollo
urbano, tomando en cuenta los principios ya consagrados en el capítulo 7 de la Agenda
21 (UNEP, 1992)
Evolution and Dynamics of Tropical River Plumes in the Great Barrier Reef: An Integrated Remote Sensing and In Situ Study
[1] The short-lived but intense discharge of freshwater from tropical rivers into the Great Barrier Reef (GBR) Lagoon and the associated salinity reductions are a critical consideration in marine research and management of the ecologically sensitive GBR World Heritage Area. Salinity provides a unique tracer that gives clues to the origin of river-borne contaminants and allows the influences of storm-induced resuspension and river discharge on turbidity to be clearly distinguished. We describe a field investigation of the evolution and dynamics of the Herbert River plume in the central GBR. Its primary goals were to use an airborne salinity mapper and in situ instruments to study the three-dimensional structure and evolution of the plume and to lay a foundation for numerical modeling studies of its dynamics. The aircraft surveys provided a rapid assessment of the plumes spatial extent, while the in situ data revealed details of its subsurface structure. The Herbert River plume was produced by heavy rainfall associated with tropical storms during the La Nina-dominated 1999/2000 monsoon season. In the near field, the surface expression of the plume boundaries was indicated by sharp color and salinity fronts that were clearly visible from the air and sea surface. In the far field and middle Lagoon, the plume was more dispersed and ultimately merged with the larger-scale salinity gradients and with the remnant plume of the more distant, and larger, Burdekin River. The plume location and structure evolved in response to changing river flows, tidal and subtidal circulation, and wind. Using Garvine\u27s Kelvin number-based scheme, the plume was classified as intermediate in dynamical character and thus is subject to a variety of forcings. The plume evolved in response to changes in the relative intensity of tidal currents and low-frequency circulation due to wind and western boundary current forcing. It also displayed a characteristic hook-shaped\u27\u27 structure, which has been identified previously in numerical plume model studies. This structure appeared in the presence of accelerating along-shelf current flow and horizontal shear and it indicates that the plume circulation had a strongly three-dimensional character. The approach demonstrates the efficacy of combining airborne and in situ methods to observe rapidly evolving coastal salinity structure and dynamics and sets the stage for future satellite-borne studies of larger-scale features showing contrasting salinity distributions
Evolution and dynamics of tropical river plumes in the Great Barrier Reef: an integrated remote sensing and in situ study
The short-lived but intense discharge of freshwater from tropical rivers into the Great Barrier Reef (GBR) Lagoon and the associated salinity reductions are a critical
consideration in marine research and management of the ecologically sensitive GBR World Heritage Area. Salinity provides a unique tracer that gives clues to the origin of
river-borne contaminants and allows the influences of storm-induced resuspension and river discharge on turbidity to be clearly distinguished. We describe a field investigation of the evolution and dynamics of the Herbert River plume in the central GBR. Its primary goals were to use an airborne salinity mapper and in situ instruments to study the three-dimensional structure and evolution of the plume and to lay a foundation for numerical modeling studies of its dynamics. The aircraft surveys provided a rapid assessment of the plumes spatial extent, while the in situ data revealed details of its subsurface structure. The Herbert River plume was produced by heavy rainfall associated with tropical storms during the La Nina-dominated 1999/2000 monsoon season. In the near field, the surface expression of the plume boundaries was indicated by sharp color and salinity fronts that were clearly visible from the air and sea surface. In the far field and middle Lagoon, the plume was more dispersed and ultimately merged with the larger-scale salinity gradients and with the remnant plume of the more distant, and larger, Burdekin River. The plume location and structure evolved in response to changing river flows, tidal and subtidal circulation, and wind. Using
Garvine’s Kelvin number-based scheme, the plume was classified as intermediate in dynamical character and thus is subject to a variety of forcings. The plume evolved in
response to changes in the relative intensity of tidal currents and low-frequency circulation due to wind and western boundary current forcing. It also displayed a
characteristic ‘‘hook-shaped’’ structure, which has been identified previously in numerical plume model studies. This structure appeared in the presence of accelerating
along-shelf current flow and horizontal shear and it indicates that the plume circulation had a strongly three-dimensional character. The approach demonstrates the efficacy of combining airborne and in situ methods to observe rapidly evolving coastal salinity structure and dynamics and sets the stage for future satellite-borne studies of larger-scale features showing contrasting salinity distributions
Fortalecimiento institucional al municipio de Santa Cruz de la Sierra, Bolivia
El programa de Apoyo para la Implementación de los Planes Nacionales de Acción SINPA
(Support for Implementation of National Plans of Action) surge para dar cumplimiento a las
políticas y directrices proclamadas durante la Conferencia de las Naciones Unidas para
los Asentamientos Humanos - HABITAT II (Estambul 1996) (UNCHS 1997) en tres
ciudades de diferentes países. En Bolivia, SINPA materializa el fortalecimiento del
Gobierno Municipal de Santa Cruz de la Sierra, ciudad tropical prometedora y de grandes
contrastes (motor del desarrollo económico, concentra los mayores índices de pobreza
absoluta del país), se rige por un convenio suscrito entre el gobierno municipal el Instituto
de Estudios de Vivienda y Desarrollo Urbano IHS (Holanda) y dos universidades locales.
El país de fuerte tradición centralista y con bajo nivel de relacionamiento y articulación
entre los estamentos político y civil, introduce a partir de 1994 drásticas reformas al
Estado una de las cuales es la descentralización que se da como municipalización. Con
este surgimiento se presentan e identifican una serie de debilidades en los gobiernos
locales para enfrentar las nuevas responsabilidades y competencias.
SINPA es un intento de subsanar esta realidad desarrollando capacidades de gestión
desde el interior del gobierno municipal, enfatizando la planificación desde cuatro pilares:
gestión ambiental, fortalecimiento institucional, participación ciudadana y desarrollo
económico local
Combinatorial Markov chains on linear extensions
We consider generalizations of Schuetzenberger's promotion operator on the
set L of linear extensions of a finite poset of size n. This gives rise to a
strongly connected graph on L. By assigning weights to the edges of the graph
in two different ways, we study two Markov chains, both of which are
irreducible. The stationary state of one gives rise to the uniform
distribution, whereas the weights of the stationary state of the other has a
nice product formula. This generalizes results by Hendricks on the Tsetlin
library, which corresponds to the case when the poset is the anti-chain and
hence L=S_n is the full symmetric group. We also provide explicit eigenvalues
of the transition matrix in general when the poset is a rooted forest. This is
shown by proving that the associated monoid is R-trivial and then using
Steinberg's extension of Brown's theory for Markov chains on left regular bands
to R-trivial monoids.Comment: 35 pages, more examples of promotion, rephrased the main theorems in
terms of discrete time Markov chain
Dispersive properties of quasi-phase-matched optical parametric amplifiers
The dispersive properties of non-degenerate optical parametric amplification
in quasi-phase-matched (QPM) nonlinear quadratic crystals with an arbitrary
grating profile are theoretically investigated in the no-pump-depletion limit.
The spectral group delay curve of the amplifier is shown to be univocally
determined by its spectral power gain curve through a Hilbert transform. Such a
constraint has important implications on the propagation of spectrally-narrow
optical pulses through the amplifier. In particular, it is shown that anomalous
transit times, corresponding to superluminal or even negative group velocities,
are possible near local minima of the spectral gain curve. A possible
experimental observation of such effects using a QPM Lithium-Niobate crystal is
suggested.Comment: submitted for publicatio
A Narrative Review of Intensive Group Tobacco Treatment: Clinical, Research, and US Policy Recommendations
Clinical practice guidelines recommend comprehensive treatment for tobacco dependence including pharmacotherapies and behavioral interventions. Group counseling may deliver unique treatment aspects not available with other modalities. This manuscript provides a narrative review of group treatment outcomes from real-world practice settings and complements recent meta-analyses of randomized controlled trials (RCTs). Our primary goals were to determine whether group treatments delivered in these settings have yielded similar quit rates compared to individual treatment and to provide recommendations for best practices and policy. Methods: Group treatment was defined as occurring in a clinical or workplace setting (ie, not provided as part of a research study), led by a professionally trained clinician, and offered weekly over several weeks. English language PubMed articles from January 2000 to July 2017 were searched to identify studies that included outcomes from both group and individual treatment offered in real-world settings. Additional data sources meeting our criteria were also included. Reports not using pharmacotherapy and research studies (eg, RCTs) were excluded. The primary outcome was short-term, carbon monoxide (CO)-validated point prevalence abstinence (4-week postquit date). Results: The review included data from 11 observational studies. In all cases, group treatment(s) had higher 4-week CO-validated quit rates (range: 35.5%-67.3%) than individual treatment(s) (range: 18.6%-53.3%). Conclusions: Best practice group treatments for tobacco dependence are generalizable from research to clinical settings and likely to be at least as effective as intensive individual treatment. The added advantages of efficiency and cost-effectiveness can be significant. Group treatment is feasible in various settings with good results. Implications: A major barrier to achieving high rates of tobacco abstinence is under-utilization of evidence-based treatment interventions. This review demonstrates the effectiveness and utility of group treatment for tobacco dependence. Based on the available data described in this narrative review in conjunction with existing RCT data, group treatment for tobacco dependence should be established and available in all behavioral health and medical settings. Group tobacco treatment is now one of the mandated reimbursable tobacco treatment formats within the US health care system, creating enormous opportunities for widespread clinical reach. Finally, comprehensive worksite group programs can further extend impact
Content Validity of Anatomic Site-Specific Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) Item Sets for Assessment of Acute Symptomatic Toxicities in Radiation Oncology
Purpose: To improve assessment of symptomatic toxicity in cancer clinical trials and complement clinician-based toxicity reporting, the US National Cancer Institute developed a measurement system called the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). The objective of this study was to examine the content validity of PRO-CTCAE in patients undergoing radiation therapy and to establish anatomic site-specific item sets for implementation in cancer research. Methods and Materials: Patients receiving radiation to the brain, head and neck, breast, thorax, abdomen, or pelvis were recruited during the final week of radiation. Participants described side effects qualitatively and completed anatomic site-specific checklists indicating the presence or absence of symptomatic toxicities drawn from the PRO-CTCAE library. Items endorsed by ≥20% of participants were selected for inclusion. Symptomatic toxicities described qualitatively were content analyzed and summarized. Symptomatic toxicities not reflected in the PRO-CTCAE item library were tabulated. Results: We conducted 389 interviews of patients receiving radiation to the brain (n = 46), head and neck (n = 69), breast (n = 134), thorax (n = 30), abdomen (n = 27), female pelvis (n = 36), or male pelvis (n = 47). Median age was 62 years; 62% were female. The 53 solicited PRO-CTCAE symptoms reflected all reported radiation-induced toxicities with the exception of phlegm/mucus production and mouth/throat pain with swallowing in patients receiving head and neck radiation, eye dryness/irritation in patients undergoing brain radiation, and obstructive urinary symptoms in men receiving pelvic radiation. The PRO-CTCAE items “skin burns” and “pain” require greater specificity to adequately reflect toxicities experienced during radiation. Conclusions: PRO-CTCAE demonstrates strong content validity as a measure of symptomatic toxicities in patients receiving radiation. These results provide empirical support for the definition of site-specific PRO-CTCAE item sets to assess the symptomatic toxicities of radiation therapy. The site-specific PRO-CTCAE item sets developed herein are currently being deployed in our department via an electronic platform to capture treatment-related toxicity
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