Using matrix norms to estimate the direction of arrival of planar waves on an ULA

SEAD method estimates the direction-of-arrival angles on an uniformly linear array based on the difference between the two largest singular values, what is called differential spectrum. Although it presented an outstanding performance, the ability to indicate the source positions was not elucidated yet. Inspired by the differential spectrum formulation we derived a total differential spectrum and found out that the matrix norm induced by the vector 2-norm of a modified spatial covariance matrix can be used to estimate the direction-of-arrival of multiple plane waves. Indeed we show that matrix norms are estimators and we propose their use instead of the singular value decomposition in SEAD-based methods. We present a general mathematical expression in order to explicit the operating principles of the proposed methods. Consequently, we were able to explain how the relation between the arriving and the search angles produces the larger peaks on the differential spectrum. To evaluate the important role played by matrix norms, a thousand experiments were carried out. They showed that the proposed approach proved to be as accurate as the previous SEAD-based methods, while providing a significant reduction on runtime. It also outperformed well-established methods like MODEX regarding the estimation error.     

Sports activity patterns and cardio-metabolic health over time among adults in Germany: Results of a nationwide 12-year follow-up study

BackgroundPhysical activity is favorable for health, and vigorous sports activity is particularly beneficial. This study investigates the association between changes in sports participation patterns over time and cardio-metabolic and self-perceived health outcomes.MethodsData from 3752 adults (18–79 years of age) who participated in 2 national health interview and examination surveys in 1997–1999 and 2008–2011 were included, with a mean follow-up time of about 12 years. A change in self-reported sports activity was analyzed with respect to the incidence of type 2 diabetes, coronary heart disease (CHD), hypertension, obesity, dyslipidemia, metabolic syndrome, and poor self-perceived health. Participants with pre-existing disease or risk factor of interest at baseline were excluded from the analysis. Being sufficiently active in sports was specified as doing sports for at least 1–2 h per week, and 4 activity categories were defined: 1) inactive at both time points (inactive–inactive), 2) inactive at baseline and active at follow-up (inactive–active), 3) active at baseline and inactive at follow-up (active–inactive), and 4) active at both time points (active–active). Associations between sports activity engagement and health outcomes were estimated by logistic regression models with different stages of adjustments.ResultsNot engaging in any regular sports activity at both time points (inactive–inactive) was associated with higher rates of type 2 diabetes (odds ratio (OR) = 1.82, 95% confidence interval (95%CI): 1.08–3.08), CHD (OR = 1.82, 95%CI: 1.16–2.84), hypertension (OR = 1.36, 95%CI: 1.03–1.81), metabolic syndrome (OR = 1.58, 95%CI: 1.08–2.32), and poor self-perceived health (OR = 2.54, 95%CI: 1.83–3.53) compared to doing regular sports for a minimum of 1–2 h per week over time (active–active). In case of change from inactivity to any regular sports activity (inactive–active), the rate of risk factor occurrence was not statistically different from the active–active reference group except for poor self-perceived health, but it was higher for type 2 diabetes (OR = 2.15, 95%CI: 1.12–4.14) and CHD (OR = 1.77, 95%CI: 1.03–3.03). Being active at baseline but inactive at follow-up (active–inactive) was not associated with higher disease incidence of type 2 diabetes (OR = 0.70, 95%CI: 0.25–1.97) or CHD (OR = 1.20, 95%CI: 0.49–2.99), but was associated with higher rates of hypertension (OR = 1.61, 95%CI: 1.11–2.34), obesity (OR = 2.34, 95%CI: 1.53–3.57), metabolic syndrome (OR = 1.70, 95%CI: 1.11–2.63), and poor self-perceived health (OR = 2.16, 95%CI: 1.53–3.07) at follow-up.ConclusionEven a low weekly quantity (1–2 h) of regular sports activity is partly associated with health benefits. Being formerly but not currently active was not associated with an increased disease incidence, but was associated with a higher risk-factor development compared to the reference group (active–active). Becoming active was preventive for risk-factor development but was not preventive for disease incidence, which probably means that the health benefits from sports activity are not sustainable and disease incidence is only shifted to a later period in life. For this reason, the promotion of and commitment to regular sports activity should be addressed as early as possible over the lifespan to achieve the best health benefits.     

Development and initial validation of a multidimensional questionnaire on the relationship to work (RWQ)

The paper presents first the theoretical foundations used to develop a pre-experimental version of a questionnaire on relationship to work, and then the four stages of its initial validation leading to an experimental version. These stages included: (1) Defining the dimensions and sub-dimensions of the relationship to work concept; (2) Operationalizing the dimensions and sub-dimensions and creating the items; (3) Verifying the face and content validity and developing the pre-experimental questionnaire; (4) Testing the pre-experimental questionnaire with 550 workers and 538 students, assessing its psychometric properties and elaborating the experimental questionnaire.

     

Performance in a simulated cricket batting innings (BATEX): reliability and discrimination between playing standards

The reliability (test-retest) of running-between-the-wickets times and skill performance was assessed during a batting exercise (BATEX) simulation of 2 h 20 min duration that requires intermittent shuttle running. In addition, performance and physiological responses (heart rate, sweat rate, rating of perceived exertion, blood lactate concentration) were compared between high- and low-grade district club batsmen (n = 22, mean ± s: age 20 ± 2 years, mass 73.4 ± 8.5 kg). Running-between-the-wickets performance was assessed with an infra-red timing system (Swift, Australia) by sampling a 5-m time for the middle section of the straight-line sprints (singles) and the time to complete 5 m in and out of the turn (5-0-5-m turn time). Skill performance was rated as a percentage for good bat-ball contacts. Coefficients of variation for running-between-the-wickets performance and percentage of good bat-ball contacts were both <5%. Percentage of good bat-ball contacts was greater in the high- than low-grade batsmen (70 ± 8 vs. 58 ± 9%, P = 0.01). All other variables were similar between grades. Running-between-the-wickets and skill-performance measures during the BATEX simulation were reliable, thus it can be used in future research.     

An education policy paradigm that fails upper secondary school pupils

In this article, we illustrate the creation of the education policy paradigm that constitutes the framework of vocational education and training (VET) programmes, and analyse local school representatives’ perception of VET in upper secondary schools in Sweden. The education policy paradigm, established through three periods of reform during the twentieth century, undervalues VET as being less worthy than general/academic education. This paradigm generates the rhetoric used by interviewed school representatives that encourages school pupils to choose the ‘right’ (academic) programmes in order to foster a specific citizenship competence, even if this competence is not fully compatible with labour market demands. Young people who cannot, or will not, attain the ‘right’ education, and thus the advocated citizenship competence, lose out in a school system where general/academic education and higher education preparatory programmes are consistently prioritised over VET. An educational system that advocates discrimination and suspicion of VET limits career options and restricts entry into the labour market, as well as risk stigmatising pupils undertaking VET; this paradigm is neither justified nor democratic.     

Learning biology and mathematics outdoors: effects and attitudes in a Swedish high school context

This research suggests that learning biology in an outdoor environment has a positive cognitive and affective impact on 13–15-year-old, Swedish high school pupils. Eighty-five pupils in four classes participated in a quasi-experimental design. Half the pupils, taking a biology course in ecology or diversity of life, had several lessons outdoors and the other half were taught indoors. All of the classes, but one, also had mathematics lessons outdoors once a week. Twenty-one pupils were interviewed five months after the course and all were positive towards the new learning environment they had experienced outdoors in biology and/or mathematics. They also valued the higher degree of interaction among the pupils. Other findings from the interviews were that the pupils from the outdoor classes showed a higher degree of long-term knowledge retention. They remembered both activities and contents better than the pupils in the indoor classes. An essay-type question assessing their biological understanding qualitatively according to the Structure of Observed Learning Outcome taxonomy revealed no differences between the groups. The results are discussed in the light of neurocognitive models of long-term memory.