Hybrid Carrier And Modulation Tracking Loop Performance In RFI

The operation of a hybrid Tracking (HT) phase-locked loop (PLL) in radio-frequency interference (RFI) is considered. Results from a perturbation analysis for the loop phase error in continuous-wave (CW) RFI are found to compare favorably with results obtained by digital computer simulation. These results, together with simulation results for wide-band (in comparison to the loop bandwidth) RFI, indicate that loop structures which track both on the signal carrier and modulation components are advantageous in RFI plus Gaussian noise backgrounds. Copyright © 1974 by The Institute of Electrical and Electronics Engineers, Inc

A diagnosis-based clinical decision rule for spinal pain part 2: review of the literature

<p>Abstract</p> <p>Background</p> <p>Spinal pain is a common and often disabling problem. The research on various treatments for spinal pain has, for the most part, suggested that while several interventions have demonstrated mild to moderate short-term benefit, no single treatment has a major impact on either pain or disability. There is great need for more accurate diagnosis in patients with spinal pain. In a previous paper, the theoretical model of a diagnosis-based clinical decision rule was presented. The approach is designed to provide the clinician with a strategy for arriving at a specific working diagnosis from which treatment decisions can be made. It is based on three questions of diagnosis. In the current paper, the literature on the reliability and validity of the assessment procedures that are included in the diagnosis-based clinical decision rule is presented.</p> <p>Methods</p> <p>The databases of Medline, Cinahl, Embase and MANTIS were searched for studies that evaluated the reliability and validity of clinic-based diagnostic procedures for patients with spinal pain that have relevance for questions 2 (which investigates characteristics of the pain source) and 3 (which investigates perpetuating factors of the pain experience). In addition, the reference list of identified papers and authors' libraries were searched.</p> <p>Results</p> <p>A total of 1769 articles were retrieved, of which 138 were deemed relevant. Fifty-one studies related to reliability and 76 related to validity. One study evaluated both reliability and validity.</p> <p>Conclusion</p> <p>Regarding some aspects of the DBCDR, there are a number of studies that allow the clinician to have a reasonable degree of confidence in his or her findings. This is particularly true for centralization signs, neurodynamic signs and psychological perpetuating factors. There are other aspects of the DBCDR in which a lesser degree of confidence is warranted, and in which further research is needed.</p

Modeling of airblast propagation through an enclosed structure

The ability to model explosively formed shock waves propagating through a structure is of particular interest to engineers concerned with structural responses to blasts. Accurate peak pressure and impulse values are critical to understanding blast loads on structures and predicting the resulting structural behavior, but are sometimes difficult to determine analytically. Experiments are necessary to determine the true structural response, but the experiments alone may not identify all the details involved in an explosive event that may be important for design purposes. When tied to experiments, computational modeling of explosive events can be an invaluable tool for an engineer. The most difficult part of modeling structural response to a close-in explosive event is capturing the fluid-structure interaction of the resulting flow of the detonation products. In this paper, we compare the results of numerical simulations of an explosive experimental event in an enclosed structure, or “attic space”, using two different computational codes, CTH and DYSMAS. Both adequately model the explosive event in attic space when compared to the experiment. We also compare the two codes’ ability to produce explosive-induced pressure-time histories in the free field. The advantage of using a coupled code like DYSMAS is that structural response can be more accurately captured than by using a hydrocode like CTH alone. The differences between the two codes’ ability to model the event are analyzed and described as well as a general description of the shock wave propagation in the attic space

Participação e impotência: a busca pela esperança na periferia de Fortaleza, Brasil

A contínua influência do desenvolvimento participativo, tanto na teoria quanto na prática, destaca o valor de processos de desenvolvimento democráticos e inclusivos. Porém, apesar da sua influência através os anos, a participação ainda encontra os desafios de definir, promover e se tornar um fenômeno empoderador. Aqui reside o “baixo-ventre” teórico de participação porque ela é inextricavelmente ligada à distribuição de poder em qualquer comunidade. Esse artigo explora uma metodologia que busca quebrar laços de poder entre os mais pobres e proporcionar canais alternativos de acesso a serviços públicos para os quais os residentes são elegíveis devido ao seu status de cidadão. Buscamos também um entendimento mais profundo de como a participação cresce, como é alimentada pelo capital social e como ela cria sua própria dinâmica interna. Dessa forma, nós concluímos que as sementes de participação existem em qualquer grupo social e que a participação é um fenômeno interno. Ela não é um projeto externo cujo critério para o sucesso é definido pela presença em encontros, mas um reagrupamento interno mais profundo dentro de um grupo social cujo objetivo comum é claramente definido. A participação é, portanto, um processo que requer tempo, paciência, e flexibilidade.Palavras-chaves: Vulnerabilidade social. Práticas democráticas. Clientelismo.Participation and Powerlessness: The Pursuit of Hope on the Periphery of Fortaleza, BrazilAbstract The continued presence of participatory development in both theory and practice highlights the perceived value of democratic and inclusive development processes. However, despite years of influence, participation still encounters challenges such as those of defining participation, promoting participation, and making participation empowering. Here lies the vulnerable theoretical underbelly of participation, because it is inextricably linked to the distribution of power in any community. This paper examines a methodology that seeks to break traditional bonds of power among the very poor and to provide alternative channels of access to the public services for which residents are eligible because of their status as citizen. It also seeks a more detailed understanding of how participation grows, how it is fed by social capital, and how it creates its own internal dynamic.  In so doing, we conclude that the seeds of participation exist in any social group and that participation is an internal phenomenon.  It is not an external project for which attendance at meetings is the criterion for success, but a deeper internal rallying within a social group around a commonly-defined goal, a process that requires time, patience, and flexibility to achieve.Keywords: Vulnerability. Democratic practices. Clientelism

Motion of Air Bubbles in Water Subjected to Microgravity Accelerations

The International Space Station (ISS) serves as a platform for microgravity research for the foreseeable future. A microgravity environment is one in which the effects of gravity are drastically reduced which then allows physical experiments to be conducted without the over powering effects of gravity. During his 6-month stay on the ISS, astronaut Donald R. Pettit performed many informal/impromptu science experiments with available equipment. One such experiment focused on the motion of air bubbles in a rectangular container nearly filled with de-ionized water. Bubbles were introduced by shaking and then the container was secured in place for several hours while motion of the bubbles was recorded using time-lapse photography. This paper shows correlation between bubble motion and quasi-steady acceleration levels during one such experiment operation. The quasi-steady acceleration vectors were measured by the Microgravity Acceleration Measurement System (MAMS). Essentially linear motion was observed in the condition considered here. Dr. Pettit also created other conditions which produced linear and circulating motion, which are the subjects of further study. Initial observations of this bubble motion agree with calculations from many microgravity physical science experiments conducted on shuttle microgravity science missions. Many crystal-growth furnaces involve heavy metals and high temperatures in which undesired acceleration-driven convection during solidification can adversely affect the crystal. Presented in this paper will be results showing correlation between bubble motion and the quasi-steady acceleration vector

The impact of confounding on the associations of different adiposity measures with the incidence of cardiovascular disease: a cohort study of 296 535 adults of white European descent

Aims: The data regarding the associations of body mass index (BMI) with cardiovascular (CVD) risk, especially for those at the low categories of BMI, are conflicting. The aim of our study was to examine the associations of body composition (assessed by five different measures) with incident CVD outcomes in healthy individuals. Methods and results: A total of 296 535 participants (57.8% women) of white European descent without CVD at baseline from the UK biobank were included. Exposures were five different measures of adiposity. Fatal and non-fatal CVD events were the primary outcome. Low BMI (≤18.5 kg m−2) was associated with higher incidence of CVD and the lowest CVD risk was exhibited at BMI of 22–23 kg m−2 beyond, which the risk of CVD increased. This J-shaped association attenuated substantially in subgroup analyses, when we excluded participants with comorbidities. In contrast, the associations for the remaining adiposity measures were more linear; 1 SD increase in waist circumference was associated with a hazard ratio of 1.16 [95% confidence interval (CI) 1.13–1.19] for women and 1.10 (95% CI 1.08–1.13) for men with similar magnitude of associations for 1 SD increase in waist-to-hip ratio, waist-to-height ratio, and percentage body fat mass. Conclusion: Increasing adiposity has a detrimental association with CVD health in middle-aged men and women. The association of BMI with CVD appears more susceptible to confounding due to pre-existing comorbidities when compared with other adiposity measures. Any public misconception of a potential ‘protective’ effect of fat on CVD risk should be challenged

Linking development to climate adaptation: Leveraging generic and specific capacities to reduce vulnerability to drought in NE Brazil

AbstractTo respond to climate impact, poor agricultural households in less developed regions rely on different types of assets that define their overall adaptive capacity (AC). However not all assets build capacity equally. In this study we argue that building AC requires a combination of interventions that address not only climate-related risks (specific capacity) but also the structural deficits (e.g., lack of income, education, health, political power) (generic capacity) that shape vulnerability. Focusing on rainfed agriculture in NE Brazil, we investigate how households leverage and combine generic and specific capacities to reduce vulnerability. Particularly we explore: 1) the relative importance of different kinds of capacity in shaping vulnerability on these households and 2) how the level of generic capacities (particularly as a result of Brazil’s anti-poverty program Bolsa Família) influences the adoption of specific ones. We find that both kinds of capacity matter, as relatively higher levels of generic capacity (in terms of income in general, and climate-neutral income specifically) are associated with higher levels of specific capacity (irrigation). In addition we find that while Bolsa Família has been positive in increasing income, it has not been sufficient to manage the risk of food insecurity during drought events, suggesting a 'poverty trap' in which families are constantly coping with drought but failing to overcome the conditions that make them vulnerable. Our findings indicate that in order to decrease climate vulnerability of poor agricultural households, development interventions, such as anti-poverty programs, have to go beyond cash transfer and should incorporate risk management policies that enhance synergies between generic and specific capacities

Focus on RNA Isolation: Obtaining RNA for MicroRNA (miRNA) Expression Profiling Analyses of Neural Tissue

MicroRNAs (miRNAs) are present in all known plant and animal tissues and appear to be somewhat concentrated in the mammalian nervous system. Many different miRNA expression profiling platforms have been described. However, relatively little research has been published to establish the importance of \u27upstream\u27 variables in RNA isolation for neural miRNA expression profiling. We tested whether apparent changes in miRNA expression profiles may be associated with tissue processing, RNA isolation techniques, or different cell types in the sample. RNA isolation was performed on a single brain sample using eight different RNA isolation methods, and results were correlated using a conventional miRNA microarray and then cross-referenced to Northern blots. Differing results were seen between samples obtained using different RNA isolation techniques and between microarray and Northern blot results. Another complication of miRNA microarrays is tissue-level heterogeneity of cellular composition. To investigate this phenomenon, miRNA expression profiles were determined and compared between highly-purified primary cerebral cortical cell preparations of rat primary E15-E18 neurons versus rat primary E15-E18 astrocytes. Finally, to assess the importance of dissecting human brain gray matter from subjacent white matter in cerebral cortical studies, miRNA expression profiles were compared between gray matter and immediately contiguous white matter. The results suggest that for microarray studies, cellular composition is important, and dissecting white matter from gray matter improves the specificity of the results. Based on these data, recommendations for miRNA expression profiling in neural tissues, and considerations worthy of further study, are discussed

Anthropology and environmental crisis

Este artigo trata do tema da crise ambiental que nos ensina sobre reconhecer a devastação ocasionada pelos processos coloniais e o esforço global por uma emancipação ambiental. Abordamos o conceito de crise ambiental no âmbito do campo de conhecimento antropológico. Objetivamos refletir sobre a tensão, a violência e o conflito na relação entre a sociedade e a natureza. Em um mundo de recursos naturais finitos, destacamos o despreparo do poder público para lidar com os desafios climáticos e impactos do aquecimento global na forma desigual com que atinge a população mundial e a urgência de serviços do Estado para a mitigação de ações predatórias e a necessária inovação de biopolíticas (nacionais e internacionais) de preservação e fiscalização acompanhadas de ampla participação social.This article addresses the theme of environmental crisis. In doing so, it helps us recognize the devastation caused by colonial processes and the global effort for environmental emancipation. As we approach the concept of environmental crisis from within the field of anthropological knowledge, we work to reflect the tensions, violence, and conflicts in the relationship between society and nature. In a world of finite natural resources, we highlight the unpreparedness of public authorities to deal with climate challenges and the unequal ways in which the impacts of global warming affect the world's population. We highlight the urgency for the need of State services to mitigate predatory actions and the necessary innovation of biopolicies (national and international) of preservation and enforcement, accomplished through broad social participation