Multipath Separation-Direction of Arrival (MS-DOA) with Genetic Search Algorithm for HF channels

Cataloged from PDF version of article.Direction-of-Arrival (DOA) defines the estimation of arrival angles of an electromagnetic wave impinging on a set of sensors. For dispersive and time-varying HF channels, where the propagating wave also suffers from the multipath phenomena, estimation of DOA is a very challenging problem. Multipath Separation-Direction of Arrival (MS-DOA), that is developed to estimate both the arrival angles in elevation and azimuth and the incoming signals at the output of the reference antenna with very high accuracy, proves itself as a strong alternative in DOA estimation for HF channels. In MS-DOA, a linear system of equations is formed using the coefficients of the basis vector for the array output vector, the incoming signal vector and the array manifold. The angles of arrival in elevation and azimuth are obtained as the maximizers of the sum of the magnitude squares of the projection of the signal coefficients on the column space of the array manifold. In this study, alternative Genetic Search Algorithms (GA) for the maximizers of the projection sum are investigated using simulated and experimental ionospheric channel data. It is observed that GA combined with MS-DOA is a powerful alternative in online DOA estimation and can be further developed according to the channel characteristics of a specific HF link. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserve

Intellectual dialogue in creative thinking (Based on the analysis of creating inventions)

One of the topical issues in the psychology of thinking is the study of conditions for successful solutions of creative tasks and problems. They include the intellectual dialogue. In this context, the authors conducted an empirical study of the intellectual dialogue in creative thinking as a condition for successful problem solving. The study was based on the theory of problem situations and structural level theory. The purpose of the research was to study the forms and functions of the intellectual dialogue at di fferent stages of solving creative problems. Hypotheses: the functions and forms of the intellectual dialogue are related to the stage of solving a creative problem; specific features of creative problem solving determine those personal characteristics of the subjects being co-authors of the intellectual dialogue that are significant for achieving a solution. The study was carried out on a sample of inventors, various specialists in the scientific and technical field of Azerbaijan and Russia, patent holders (N = 17) aged 42 to 80 years old, (65% of males, 35% of females). The researchers used the original methodology (by F. S. Keberlinskaya, A. A. Matyushkina) that is aimed at assessing the forms and functions of the intellectual dialogue with the help of the thinking personalities’ ‘roles’ (Ch. M. Gadzhiyev) in relation to the process of creating their own inventions at its various stages. Diagnostics of personal characteristics was carried out with the help of the “Five-Factor Personality Model Questionnaire” (Robert R. McCrae, Paul T. Costa) adapted by A. B. Khromov, and the test by K. Thomas “Con flict Mode Instrument” (Kenneth W. Thomas, Ralph H. Kilmann) adapted by N. V. Grishina. The results show that the intellectual dialogue performs different functions correlated to the stage of problem solving in the process of creative problem solving that leads to a new invention at the level of discovery in the scientific and technical field and its later implementation in practice. At the stage of problem statement, the internal dialogue is significant for the author of the idea. This dialogue serves to understand the meaning of the problem as potentially solvable. At the stages of hypothesizing and developing final solutions, the role of an external dialogue is essential. This dialogue performs the functions of providing additional information and synthesizing it from different fields of knowledge

Low-Dose CT Image Enhancement Using Deep Learning

The application of ionizing radiation for diagnostic imaging is common around the globe. However, the process of imaging, itself, remains to be a relatively hazardous operation. Therefore, it is preferable to use as low a dose of ionizing radiation as possible, particularly in computed tomography (CT) imaging systems, where multiple x-ray operations are performed for the reconstruction of slices of body tissues. A popular method for radiation dose reduction in CT imaging is known as the quarter-dose technique, which reduces the x-ray dose but can cause a loss of image sharpness. Since CT image reconstruction from directional x-rays is a nonlinear process, it is analytically difficult to correct the effect of dose reduction on image quality. Recent and popular deep-learning approaches provide an intriguing possibility of image enhancement for low-dose artifacts. Some recent works propose combinations of multiple deep-learning and classical methods for this purpose, which over-complicate the process. However, it is observed here that the straight utilization of the well-known U-NET provides very successful results for the correction of low-dose artifacts. Blind tests with actual radiologists reveal that the U-NET enhanced quarter-dose CT images not only provide an immense visual improvement over the low-dose versions, but also become diagnostically preferable images, even when compared to their full-dose CT versions

Effects of photoperiod length and light intensity on performance, carcass characteristics and heterophil to lymphocyte ratio in broilers

The aim of this study was to investigate the effects of photoperiod length and light intensity on performance, carcass characteristics and heterophil to lymphocyte ratio in broilers. A total of 272 1 day-old male broiler chicks (Ross 308) were randomly assigned to four treatment groups based on the photoperiod length (23L:1D or increasing duration of light) and light intensity (20 lux vs. a dim, reducing intensity) with four replicates. At 42 d of age, effects of photoperiod length and light intensity on performance traits were not significant. The heterophil/ lymphocyte ratio in 20 lux and dim, reducing light intensity groups were 0.30 and 0.15 (P<0.001), respectively. On the other hand, the effect of light intensity has no influence on heterophil/lymphocyte ratio. Cold and hot carcass weights and whole breast meat and wing weights were found lower in the dim, reducing light intensity group than 20 lux light intensity group. The effects of photoperiod length and light intensity on carcass characteristics were not significant, statistically. In conclusion, it can be said that body weight, feed consumption, feed convertion ratio, whole breast meat and wing weights were increased by providing the increasing photoperiod used with a 20 lux light intensity in broiler breeding

How do ecological perspectives help understand schools as sites for teacher learning?

Schools are sites of teachers’ professional learning for both new entrants and experienced practitioners. In this paper, schools are conceptualised as complex, multidimensional ecologies that are constituted by the relations that exist between school leaders, teachers, mentors and all members of the school community. As relational environments, the conditions affecting professional learning – both formal and informal – are constantly dynamic, with multiple and simultaneous interactions taking place between these stakeholders. Interactions are also multi-layered – between the school system, individuals, classrooms, the community and the policy environment. School leaders are a major influence on these dynamics and affect how schools act as sites of professional formation, mediating external policy as well as affecting micro-dynamics within individual school systems. The challenge of realising professional learning within these relational contexts can be viewed as a ‘wicked problem’, a feature of complex systems that resists simplified solutions. In conceptualising a complex ecology at work, we illuminate the relational dynamics with a focus, for all stakeholders within schools, including leaders, on the need to recognise and value the importance of ‘emergence’ in professional learning. This means embracing inevitable uncertainty as a feature of schools as complex systems

Astrocyte-derived Wnt growth factors are required for endothelial blood-brain barrier maintenance

Maintenance of the endothelial blood-brain-barrier (BBB) through Wnt/β-catenin signalling is essential for neuronal function. The cells however, providing Wnt growth factors at the adult neurovascular unit (NVU) are poorly explored. Here we show by conditionally knocking out the evenness interrupted (Evi) gene in astrocytes (Evi(ΔAC)) that astrocytic Wnt release is crucial for BBB and NVU integrity. Evi(ΔAC) mice developed brain oedema and increased vascular tracer leakage. While brain vascularization and endothelial junctions were not altered in 10 and 40 week-old mice, endothelial caveolin(Cav)-1-mediated vesicle formation was increased in vivo and in vitro. Moreover, astrocytic end-feet were swollen, and aquaporin-4 distribution was disturbed, coinciding with decreased astrocytic Wnt activity. Vascular permeability correlated with increased neuronal activation by c-fos staining, indicative of altered neuronal function. Astrocyte-derived Wnts thus serve to maintain Wnt/β-catenin activity in endothelia and in astrocytes, thereby controlling Cav-1 expression, vesicular abundance, and end-feet integrity at the NVU

Recent inventions in additive manufacturing: holistic review

This general review paper presents a condensed view of recent inventions in the Additive Manufacturing (AM) field. It outlines factors affecting the development and commercialization of inventions via research collaboration and discusses breakthroughs in materials and AM technologies and their integration with emerging technologies. The paper explores the impact of AM across various sectors, including the aerospace, automotive, healthcare, food, and construction industries, since the 1970s. It also addresses challenges and future directions, such as hybrid manufacturing and bio-printing, along with socio-economic and environmental implications. This collaborative study provides a concise understanding of the latest inventions in AM, offering valuable insights for researchers, practitioners, and decision makers in diverse industries and institutions

Analysing the Large Decline in Coronary Heart Disease Mortality in the Icelandic Population Aged 25-74 between the Years 1981 and 2006

BACKGROUND: Coronary heart disease (CHD) mortality rates have been decreasing in Iceland since the 1980s. We examined how much of the decrease between 1981 and 2006 could be attributed to medical and surgical treatments and how much to changes in cardiovascular risk factors. METHODOLOGY: The previously validated IMPACT CHD mortality model was applied to the Icelandic population. The data sources were official statistics, national quality registers, published trials and meta-analyses, clinical audits and a series of national population surveys. PRINCIPAL FINDINGS: Between 1981 and 2006, CHD mortality rates in Iceland decreased by 80% in men and women aged 25 to 74 years, which resulted in 295 fewer deaths in 2006 than if the 1981 rates had persisted. Incidence of myocardial infarction (MI) decreased by 66% and resulted in some 500 fewer incident MI cases per year, which is a major determinant of possible deaths from MI. Based on the IMPACT model approximately 73% (lower and upper bound estimates: 54%-93%) of the mortality decrease was attributable to risk factor reductions: cholesterol 32%; smoking 22%; systolic blood pressure 22%, and physical inactivity 5% with adverse trends for diabetes (-5%), and obesity (-4%). Approximately 25% (lower and upper bound estimates: 8%-40%) of the mortality decrease was attributable to treatments in individuals: secondary prevention 8%; heart failure treatments 6%; acute coronary syndrome treatments 5%; revascularisation 3%; hypertension treatments 2%, and statins 0.5%. CONCLUSIONS: Almost three quarters of the large CHD mortality decrease in Iceland between 1981 and 2006 was attributable to reductions in major cardiovascular risk factors in the population. These findings emphasize the value of a comprehensive prevention strategy that promotes tobacco control and a healthier diet to reduce incidence of MI and highlights the potential importance of effective, evidence based medical treatments

Religious Officials' knowledge, attitude, and behavior towards smoking and the new tobacco law in Kahramanmaras, Turkey

<p>Abstract</p> <p>Background</p> <p>Tobacco control effort should be first started in people that are looked upon as role models for the general population. We aimed to determine the knowledge, attitude, and behavior of religious officials towards smoking and the new tobacco law.</p> <p>Method</p> <p>The study group was comprised of 492 Imams and 149 Quran course instructors working in Kahramanmaras city of Turkey, 641 religious officials in total, and our survey form was applied on 406 (63.3%) of those religious officials who agreed to participate in the study.</p> <p>Results</p> <p>Twenty-eight (6.9%) participants were current smokers and 35 (8.6%) were ex-smokers. 99.8% of the religious officials believed that smoking was harmful and/or prohibited in terms of religion. While 43.6% respondents thought smoking was "<it>haram</it>" (forbidden by Islam), 56.2% believed it was "<it>makruh</it>" (something regarded as reprehensible, though not forbidden by God according to Islam). 85.2% of the participants were aware of the recent tobacco law. 55.5% of the respondents, who were aware of the recent tobacco law, evaluated their knowledge level on the law as adequate, whereas 44.5% evaluated it as inadequate 92.4% of the participants noted that religious officials should play active roles in tobacco control effort.</p> <p>Conclusion</p> <p>Smoking rate among religious officials is much lower than that of general public. In order to help religious officials to take a more active role on this issue, they should be trained on the subject and appropriate platforms should be established.</p