443 research outputs found
The effects of localized damping on structural response
The effect of localized structural damping on the excitability of higher order normal modes of the large space telescope was investigated. A preprocessor computer program was developed to incorporate Voigt structural joint damping models in a NASTRAN finite-element dynamic model. A postprocessor computer program was developed to select critical modes for low-frequency attitude control problems and for higher frequency fine-stabilization problems. The mode selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensors, and on image-plane motions due to sinusoidal or random power spectral density force and torque inputs
Probabilistic computer model of optimal runway turnoffs
Landing delays are currently a problem at major air carrier airports and many forecasters agree that airport congestion will get worse by the end of the century. It is anticipated that some types of delays can be reduced by an efficient optimal runway exist system allowing increased approach volumes necessary at congested airports. A computerized Probabilistic Runway Turnoff Model which locates exits and defines path geometry for a selected maximum occupancy time appropriate for each TERPS aircraft category is defined. The model includes an algorithm for lateral ride comfort limits
Calibración de sensores de humedad capacitivos usando redes neuronales
X Jornadas de Investigación de la Zona no Saturada del Suelo, Salamanca (España), 2011El estudio de la variabilidad espacial de la
humedad del suelo a escala de parcela o cuenca agrícola
requiere el uso de redes de sensores de humedad de bajo
coste, que suelen mostrar una fiabilidad limitada y requieren
de calibraciones específicas, especialmente en suelos con
elevados contenidos en arcilla. El presente trabajo pretende
plantear una calibración más fiable de sondas de humedad
mediante un análisis mixto campo-laboratorio. Para la
calibración de campo se dispone de datos gravimétricos;
para la calibración en laboratorio se han usado columnas de
suelo inalterado que tras ser saturadas fueron desecadas en
un entorno controlado mientras se monitorizaba la
evolución de su peso y la de su humedad volumétrica,
medida con diferentes sondas capacitivas Decagon. Tras
obtener curvas de secado y la relación entre la humedad
gravimétrica y la volumétrica es posible realizar una
calibración mejorada específica para cada tipo de suelo. Las
redes neuronales son particularmente útiles para el
modelado de procesos físicos y el ajuste de modelos. En
este trabajo se propone el empleo de dichas herramientas
para obtener calibraciones para las sondas analizadas en el
tipo de suelo objeto de estudio. Los resultados muestran que
dichas calibraciones permiten mejorar la precisión de las
mediciones de humedad realizadas.The study of the spatial variability of soil
water content at agricultural plot or catchment scales
requires the use of low-cost soil water content sensor
networks, which usually show a limited reliability and
require specific calibrations, specially for soils with a high
clay content. This work proposes a more reliable calibration
of soil water content probes with a laboratory analysis.
Minimally disturbed soil columns were saturated with water
and dried in a controlled environment while monitorizing
the evolution of their volumetric soil water content (with
different capacitive Decagon Probes) and weights. After
obtaining the drying curves and the relation between the
volumetric and the measured gravimetric soil water contents
it is possible to achieve an improved calibration specific for
different kinds of soil. Neural networks are especially
interesting for the modeling of physical processes and
model adjustment. In this work, these tools were used in
order to obtain improved calibrations for the analyzed
probes in the studied soil type. Results show that this
calibration improves the accuracy and pMinisterio de Ciencia e Innovación AGL2009 C03-03Junta de Andalucía AGR-478
Measurement Properties of ID-PALL, A New Instrument for the Identification of Patients With General and Specialized Palliative Care Needs.
To improve access to palliative care, identification of patients in need of general or specialized palliative care is necessary. To our knowledge, no available identification instrument makes this distinction. ID-PALL is a screening instrument developed to differentiate between these patient groups.
To assess the structural and criterion validity and the inter-rater agreement of ID-PALL.
In this multicenter, prospective, cross-sectional study, nurses and physicians assessed medical patients hospitalized for 2 to 5 days in two tertiary hospitals in Switzerland using ID-PALL. For the criterion validity, these assessments were compared to a clinical gold standard evaluation performed by palliative care specialists. Structural validity, internal consistency and inter-rater agreement were assessed.
2232 patients were assessed between January and December 2018, 97% by nurses and 50% by physicians. The variances for ID-PALL G and S are explained by two factors, the first one explaining most of the variance in both cases. For ID-PALL G, sensitivity ranged between 0.80 and 0.87 and specificity between 0.56 and 0.59. ID-PALL S sensitivity ranged between 0.82 and 0.94, and specificity between 0.35 and 0.64. A cut-off value of 1 delivered the optimal values for patient identification. Cronbach's alpha was 0.78 for ID-PALL G and 0.67 for ID-PALL S. The agreement rate between nurses and physicians was 71.5% for ID-PALL G and 64.6% for ID-PALL S.
ID-PALL is a promising screening instrument allowing the early identification of patients in need of general or specialized palliative care. It can be used by nurses and physicians without a specialized palliative care training. Further testing of the finalized clinical version appears warranted
A meta-analysis of the effects of agricultural management on soil physical quality for different farm typologies across Europe
Póster presentado en la Conferencia EGU 2014, 27 Abril - 7 Mayo 2014, Viena, Austri
Some problems of the determination of best management practices to maintain the quality of agricultural soils
Póster presentado en la Conferencia ELS 2014, 22-25 Septiembre 2014, Bari, ItaliaIn spite of the great effort of scientific research exploring the influence of agricultural practices on soil quality,
many aspects remain unclear, possibly precluding a more general adoption of the best management systems by
farmers and land use planners.
Among other causes of this knowledge gap, the wide variety of agricultural practices due to different climates,
landforms, soils, and crop types make hard to find either a general best management system or at least common
rules of larger applicability. Nevertheless the more important problem is that we usually consider soil as an
invariant entity which does not change, or if it does, its changes are controlled.
The purpose of this report is the discussion of the results of a meta-analysis of the effects of agricultural
management practices on physical aspects of soil quality, throughout the published research data of countries
of the central and western part of the European continent. Soil physical quality was evaluated through several
indicators which were evaluated in the research reports found. The indicators were: bulk density, resistance to
penetration, stability of aggregates, permeability and water and sediment yield.
The results indicate that there are agricultural practices which could be classified as convenient, although their
possible advantages are not always evident, as, for instance, direct drilling as compared to conventional tillage,
where the farm operations induce a certain compaction not always alleviated in absence of tillage.
To further explore some of the results, the evolution of some properties of a clay soil subject to a long term
experiment in dry farming conditions in southern Spain is considered. The evolution of the soil properties must be
taken into account, for a more precise evaluation of the efficiency of management practices
Mechanism of polyubiquitination by human anaphase-promoting complex: RING repurposing for ubiquitin chain assembly.
Polyubiquitination by E2 and E3 enzymes is a predominant mechanism regulating protein function. Some RINGE3s, including anaphase-promoting complex/cyclosome (APC), catalyze polyubiquitination by sequential reactions with two different E2s. An initiating E2 ligates ubiquitin to an E3-bound substrate. Another E2 grows a polyubiquitin chain on the ubiquitin-primed substrate through poorly defined mechanisms. Here we show that human APC's RING domain is repurposed for dual functions in polyubiquitination. The canonical RING surface activates an initiating E2-ubiquitin intermediate for substrate modification. However, APC engages and activates its specialized ubiquitin chain-elongating E2 UBE2S in ways that differ from current paradigms. During chain assembly, a distinct APC11 RING surface helps deliver a substrate-linked ubiquitin to accept another ubiquitin from UBE2S. Our data define mechanisms of APC/UBE2S-mediated polyubiquitination, reveal diverse functions of RING E3s and E2s, and provide a framework for understanding distinctive RING E3 features specifying ubiquitin chain elongation
Tests at 2K of the beta 0.35 spoke cryomodule prototype with the MTCA.4-based Low Level RF system prototype for the MYRRHA R&D
Within the framework of the first phase of MYRRHA (Multi-purpose hYbrid
Research Reactor for High-tech Applications) project, called MINERVA, IJCLab
was in charge of a fully equipped Spoke cryomodule prototype development,
tested at 2K. It integrates two superconducting single spoke cavities, the RF
power couplers and the Cold Tuning Systems associated. On the control side, a
MTCA.4-based Low Level Radio Frequency (LLRF) system prototype and the
Software/EPICS developments has been realized by IJCLab and the SCK CEN in
collaboration with the company IOxOS Technologies. The final version of the
global system and the results of the tests at 2K will show with some
perspectives.Comment: Poster pr\'esent\'e au LLRF Workshop 2023 (LLRF2023, arXiv :
2310.03199
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