843 resultados para Artificial satellites in search and rescue operations.


Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper presents the validation of five syntaxonomic concepts –two orders (Callitricho hamulatae-Ranunculetalia aquatilis, Zannichellietalia pedicellatae) and three alliances (Ranunculion aquatilis, Nelumbion nuciferae and Caricion viridulo-trinervis).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Charge exchange followed by radiative stabilization are the main processes responsible for the recent observations of X-ray emission from comets in their approach to the Sun. A new apparatus was constructed at JPL to measure, in collisions of HCIs with atoms and molecules, (a) absolute cross sections for single and multiple charge exchange, and (b) normalized X-ray emission cross sections. The ions are produced by the JPL HCI Facility and passed through a neutral-gas target cell. The product charge states are analyzed by a retarding potential difference technique. Results are made absolute by measuring target pressure, and incident and product ion currents. X-rays emitted from the product ions are detected with a Ge solid-state detector having a resolution of approximately 100 eV. X-ray astronomy has taken major steps forward with the recent launch of the high-resolution satellites Chandra and Newton. The cross sections reported herein are essential for the development of the solar wind comet interaction models inspired by these observations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Planar periodic metallic arrays behave as artificial magnetic conductor (AMC) surfaces when placed on a grounded dielectric substrate and they introduce a zero degrees reflection phase shift to incident waves. In this paper the AMC operation of single-layer arrays without vias is studied using a resonant cavity model and a new application to high-gain printed antennas is presented. A ray analysis is employed in order to give physical insight into the performance of AMCs and derive design guidelines. The bandwidth and center frequency of AMC surfaces are investigated using full-wave analysis and the qualitative predictions of the ray model are validated. Planar AMC surfaces are used for the first time as the ground plane in a high-gain microstrip patch antenna with a partially reflective surface as superstrate. A significant reduction of the antenna profile is achieved. A ray theory approach is employed in order to describe the functioning of the antenna and to predict the existence of quarter wavelength resonant cavities.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Raman satellites have been observed in the scattering of a Nd:YAG laser (532 nm) from a laser-ablated Mg plasma plume. We identify them as originating from transitions between the fine-structure components of the metastable 3s3p P-3(0,1,2) level of Mg. We have calculated the cross sections for Raman and Rayleigh scattering from the metastable state. Comparison of the expected ratio of the satellites to the Rayleigh peak indicates the changing population fraction of the metastable states in the plume.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Twenty-eight novel salts with tetramethyl-, tetraethyl-, and tetrabutylammonium and 1-butyl-3-methylimidazolium cations paired with 3,5-dinitro-1,2,4-triazolate, 4-nitro-1,2,3-triazolate, 2,4-dinitroimidazolate, 4,5-dinitroimidazolate, 4,5-dicyanoimidazolate, 4-nitroimidazolate, and tetrazolate anions have been prepared and characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and single-crystal Xray crystallography. The effects of cation and anion type and structure on the physicochemical properties of the resulting salts, including several ionic liquids, have been examined and discussed. Ionic liquids (defined as having m.p. <100 degrees C) were obtained with all combinations of the 1-butyl-3-methylimidazolium cation ([C(4)mim](+)) and the heterocyclic azolate anions studied, and with several combinations of tetraethyl or tetrabutylammonium cations and the azolate anions. The [C(4)mim](+) azolates were liquid at room temperature exhibiting large liquid ranges and forming glasses on cooling with glasstransition temperatures in the range of -53 to -82 degrees C (except for the 3,5-dinitro-1,2,4-triazolate salt with m.p. 33 degrees C). Six crystal structures of the corresponding tetraalkylammonium salts were determined and the effects of changes to the cations and anions on the packing of the structure have been investigated.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The decision of the U.S. Supreme Court in 1991 in Feist Publications, Inc. v. Rural Tel. Service Co. affirmed originality as a constitutional requirement for copyright. Originality has a specific sense and is constituted by a minimal degree of creativity and independent creation. The not original is the more developed concept within the decision. It includes the absence of a minimal degree of creativity as a major constituent. Different levels of absence of creativity also are distinguished, from the extreme absence of creativity to insufficient creativity. There is a gestalt effect of analogy between the delineation of the not original and the concept of computability. More specific correlations can be found within the extreme absence of creativity. "[S]o mechanical" in the decision can be correlated with an automatic mechanical procedure and clauses with a historical resonance with understandings of computability as what would naturally be regarded as computable. The routine within the extreme absence of creativity can be regarded as the product of a computational process. The concern of this article is with rigorously establishing an understanding of the extreme absence of creativity, primarily through the correlations with aspects of computability. The understanding established is consistent with the other elements of the not original. It also revealed as testable under real-world conditions. The possibilities for understanding insufficient creativity, a minimal degree of creativity, and originality, from the understanding developed of the extreme absence of creativity, are indicated. 

Relevância:

100.00% 100.00%

Publicador:

Resumo:

It is becoming clear that, contrary to earlier expectations, the application of AI techniques to law is not as easy nor as effective as some claimed. Unfortunately, for most AI researchers, there seems to be little understanding of just why this is. In this paper I argue, from empirical study of lawyers in action, just why there is a mismatch between the AI view of law, and law in practice. While this is important and novel, it also - if my arguments are accepted - demonstrates just why AI will never have success in producing the computerised lawyer.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Chemical species can serve as inputs to supramolecular devices so that a luminescence output is created in a conditional manner. Conditionality is built into these devices by employing the classical photochemical process of photoinduced electron transfer (PET) to compete with luminescence emission. The response of these devices in the analogue regime leads to sensors that can operate in nanometric, micrometric, and millimetric spaces. Some of these devices serve in membrane science, cell physiology, and medical diagnostics. The response in the digital regime leads to Boolean logic gates. Some of these find application in improving aspects of medical diagnostics and in identifying small objects in large populations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Treatment foster care (TFC) is a foster family-based intervention that aims to provide young people (and, where appropriate, their families) with a tailored programme designed to effect positive changes in their lives. TFC was designed specifically to cater for the needs of children whose difficulties or circumstances place them at risk of multiple placements and/or more restrictive placements such as hospital or secure residential or youth justice settings.

Objectives: To assess the impact of TFC on psychosocial and behavioural outcomes, delinquency, placement stability, and discharge status for children and adolescents who require out-of-home placement.

Search methods: We searched the Cochrane Controlled Trials Register (CENTRAL) 2006 (Issue 4), MEDLINE (1966 to January 2007), CINAHL (1982 to December 2006), PsycINFO (1872 to January 2007), ASSIA (1987 to January 2007), LILACS (1982 to January 2007), ERIC (1966 to January 2007), Sociological Abstracts (1963 to January 2007), and the National Research Register 2006 (Issue 4).

Selection criteria: Included studies were randomised controlled trials investigating the effectiveness of TFC with children and young people up to the age of 18 who, for reasons of severe medical, social, psychological and behavioural problems, were placed in out of home care in restrictive settings (e.g. secure residential care, psychiatric hospital) or at risk of placement in such settings.

Data collection and analysis: Titles and abstracts identified in the search were independently assessed for eligibility by the two authors (GM and WT) who also extracted and entered into REVMAN. Date were synthesised on the few occasions where this was possible. Results are presented in tabular, graphical (forest plots) and textual form.

Main results: Five studies including 390 participants were included in this review. Data suggest that treatment foster care may be a useful intervention for children and young people with complex emotional, psychological and behavioural need, who are at risk of placements in nonfamily settings that restrict their liberty and opportunities for social inclusion.

Authors’ conclusions: Although the inclusion criteria for this systematic review set a study design threshold higher than that of previous reviews, the results mirror those of earlier reviews but also highlights the tendency of the perceived effectiveness of popular interventions to outstrip their evidence base. Whilst the results of individual studies generally indicate that TFC is a promising intervention for children and youth experiencing mental health problems, behavioural problems or problems of delinquency, the evidence base is less robust than that usually reported.The Cochrane Database of Systematic Reviews is a peer reviewed, international journal, published electronically each month. The 2010 Inpact Factor for the Cochrane Database of Systematic Reviews was 6.185.The CDSR is now ranked in the top 10 of the 151 in the Medicine, General & Internal category.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

On 25 April 1998, a breach of the tailings dam of the Los Frailes pyrite mine in southwestern Spain resulted in the release of 6 million m(3) of acidic water and toxic sludge high in heavy metals. Contaminated material extended 40 km downstream, affecting agricultural land and parts of the wildlife-rich Donana Natural and National Parks, including the Entremuros, a very important area for birds. We report on the concentrations, distributions and bioavailability of zinc and cadmium in soil and vegetation from the Entremuros in November 1998 and October 1999, following 2 'cleanup' operations. Levels of Zn and Cd in soil increased significantly over this period, although this was not reflected consistently in metal concentrations in emergent macrophytes. We recommend monitoring of further cleanup attempts in order to develop means of minimizing potential impacts to wildlife in the area.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper examines the applicability of a digital manufacturing framework to the implementation of a Value Driven Design (VDD) approach for the development of a stiffened composite panel. It presents a means by which environmental considerations can be integrated with conventional product and process design drivers within a customized, digital environment. A composite forming process is used as an exemplar for the work which creates a collaborative environment for the integration of more traditional design drivers with parameters related to manufacturability as well as more sustainable processes and products. The environmental stakeholder is introduced to the VDD process through a customized product/process/resource (PPR) environment where application specific power consumption and material waste data has been measured and characterised in the process design interface. This allows the manufacturing planner to consider power consumption as a concurrent design driver and the inclusion of energy as a parameter in a VDD approach to the development of efficiently manufactured, sustainable transport systems.