Experimental Time Study (Rome)

Combined media on photographic paper. 76" x 40"

A time study

This paper presents a time study of a classroom with the goal of evaluating how time was spent. The time study allows evaluation of teaching methods and classroom interactions.

Systematic motion and time study,

Bibliography: p. 211-226.

[Three papers on motion and time study]

[no. 1] Necessary motions to perform operations.--[no. 2] Dictionary of motion study, words and terms.--[no. 3] Time definitions.

U. E. guide to wage payment plans, time study and job evaluation.

Mode of access: Internet.

Collective agreements on time and motion study;

Mode of access: Internet.

Study of the muscular activation in obese and non-obese subjects during lifting loads

The obesity prevalence is increasing among the workforce of the developed countries. However, obesity seems to negatively affect the individuals’ work performance. In occupational contexts, manual lifting tasks are frequent and can produce significant muscle loading. With the aim of analysing the possible effect of obesity on workers’ muscular activation, surface electromyography data were collected from six muscles recruited during these tasks. In the current study, 6 different tasks of manual lifting (3 loads × 2 lifting styles) were performed by 14 participants with different obesity levels. Electromyography data normalization was based on the percentage of maximum contraction during each task. The muscles’ activation times before each task were also calculated. The current study suggests that obesity can increase the maximum contraction during each task and the delays on muscles’ activation time. This study suggests that obese individuals can present some changes on their muscle activation during lifting, when comparing with non-obese individuals, and reinforces the need to develop further studies focused on obesity as a risk factor for musculoskeletal disorders development.

Smoking behaviour, former quit attempts and intention to quit in urban adolescents and young adults: A five-year longitudinal study

OBJECTIVES: To examine smoking behaviour, former quit attempts and intention to quit among Swiss adolescents and young adults over five year's time. STUDY DESIGN: five-year longitudinal study (2003, 2005 and 2008) based on a random urban community sample (N = 1345 complete cases). METHODS: Data were collected by computer-assisted telephone interviews with adolescents (16-17) and young adults (18-24). Main outcome measures included self-reported smoking behaviour, former quit attempts, smoking cessation methods and current intentions to quit smoking. RESULTS: Adolescents were more often non-smokers and less often daily smokers when compared to young adults at baseline (χ(2)(4) = 28.68, P < .001). Their smoking behaviour increased significantly from baseline to follow-up (T = 1445.50, r = .20, P < .001) in contrast to the stable smoking behaviour in young adults (χ(2)(2) = .12, n.s.). In longitudinal analyses young adults were also more stable in their smoking status at the later measurement points. In comparison adolescents changed their smoking status more often being non-smokers at baseline and smokers later on. Independently of the age group, the majority of smokers already had previously attempted to quit (65%) or intended to give up smoking at some point (72%). However only 17% were motivated to make the quit attempt within the next 6 months. Self-quitting was the preferred method, and 25% of the self-quitters had been successful. CONCLUSION: This study illustrates that different developments in smoking behaviour exist in adolescents and young adults. Our study reveals that a majority of smokers are willing to quit but often fail. Furthermore, the data indicates that for adolescents the focus should lie on primary prevention.

Evaluation of two round baling systems for harvesting understory biomass

The objective of this study was to evaluate the performance and to estimate costs of two round baling systems for harvesting understory biomass. One system was a cutter-shredderbaler prototype (Bio-baler). The other system required two successive operations. The first operation was cutting and shredding with a Supertrak tractor equipped with a Fecon mulcher head. The second operation was baling with a Claas baler. The machines were evaluated in three different pine stands on the Osceola National Forest in Florida, United States. Data collection included time study, fuel consumption and bale measurements. Material was collected from a sample of bales for heat and moisture content determination. On the most representative site (Site 2), the Bio-baler recovered 8.05 green t ha(-1) while the mulcher and the Claas baler recovered 9.75 green t ha(-1) (43 and 52 percent of original understory biomass, respectively). Productivity was 0.30 ha h(-1) for the Bio-baler and 0.51 ha h(-1) for the Claas baler. Density of the bales was 321 green kg m(-3) for the Bio-baler and 373 green kg m(-3) for the Claas baler. Average net heat content was 6263 MJ bale(-1) for the Bio-baler and 6695 MJ bale(-1) for the Claas baler with biomass containing 38 percent of moisture content on a wet basis. cost per unit area was less with the Bio-baler (US$320.91 ha(-1)) than with the mulcher-baler system (US$336.62-US$596.77 ha(-1)). Published by Elsevier Ltd.

Pedagogia diferenciada no 1º ciclo do Ensino Básico

Mestrado (PES II), Educação Pré-Escolar e Ensino do 1º Ciclo do Ensino Básico, 3 de Julho de 2014, Universidade dos Açores.

Persistence characteristics in financial prices: evidence from the portuguese stock market returns

The objective of this article is to provide additional knowledge to the discussion of long-term memory, leaning over the behavior of the main Portuguese stock index. The first four moments are calculated using time windows of increasing size and sliding time windows of fixed size equal to 50 days and suggest that daily returns are non-ergodic and non-stationary. Seeming that the series is best described by a fractional Brownian motion approach, we use the rescaled-range analysis (R/S) and the detrended fluctuation analysis (DFA). The findings indicate evidence of long term memory in the form of persistence. This evidence of fractal structure suggests that the market is subject to greater predictability and contradicts the efficient market hypothesis in its weak form. This raises issues regarding theoretical modeling of asset pricing. In addition, we carried out a more localized (in time) study to identify the evolution of the degree of long-term dependency over time using windows 200-days and 400-days. The results show a switching feature in the index, from persistent to anti-persistent, quite evident from 2010.

Long-term memory in financial prices: evidence from the Dutch stock market returns

Prepared for presentation at the Portuguese Finance Network International Conference 2014, Vilamoura, Portugal, June 18-20