SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Arithmetic mean

259

To identify what features of online social networks can increase physical activity, we conducted a 4-arm randomized controlled trial in 2014 in Philadelphia, PA. Students (n = 790, mean age = 25.2) at an university were randomly assigned to one of four conditions composed of either supportive or competitive relationships and either with individual or team incentives for attending exercise classes. The social comparison condition placed participants into 6-person competitive networks with individual incentives. The social support condition placed participants into 6-person teams with team incentives. The combined condition with both supportive and competitive relationships placed participants into 6-person teams, where participants could compare their team’s performance to 5 other teams' performances. The control condition only allowed participants to attend classes with individual incentives. Rewards were based on the total number of classes attended by an individual, or the average number of classes attended by the members of a team. The outcome was the number of classes that participants attended. Data were analyzed using multilevel models in 2014. The mean attendance numbers per week were 35.7, 38.5, 20.3, and 16.8 in the social comparison, the combined, the control, and the social support conditions. Attendance numbers were 90% higher in the social comparison and the combined conditions (mean = 1.9, SE = 0.2) in contrast to the two conditions without comparison (mean = 1.0, SE = 0.2) (p = 0.003). Social comparison was more effective for increasing physical activity than social support and its effects did not depend on individual or team incentives.

Concepts: Control, Comparison, Randomness, Grammatical number, Arithmetic mean, Average, The A-Team, Randomized controlled trial

245

Wikipedia has quickly become one of the most frequently accessed encyclopedic references, despite the ease with which content can be changed and the potential for ‘edit wars’ surrounding controversial topics. Little is known about how this potential for controversy affects the accuracy and stability of information on scientific topics, especially those with associated political controversy. Here we present an analysis of the Wikipedia edit histories for seven scientific articles and show that topics we consider politically but not scientifically “controversial” (such as evolution and global warming) experience more frequent edits with more words changed per day than pages we consider “noncontroversial” (such as the standard model in physics or heliocentrism). For example, over the period we analyzed, the global warming page was edited on average (geometric mean ±SD) 1.9±2.7 times resulting in 110.9±10.3 words changed per day, while the standard model in physics was only edited 0.2±1.4 times resulting in 9.4±5.0 words changed per day. The high rate of change observed in these pages makes it difficult for experts to monitor accuracy and contribute time-consuming corrections, to the possible detriment of scientific accuracy. As our society turns to Wikipedia as a primary source of scientific information, it is vital we read it critically and with the understanding that the content is dynamic and vulnerable to vandalism and other shenanigans.

Concepts: Scientific literature, Newspaper, Arithmetic mean, Standard Model, Physics, Wikipedia, Science, Editing

183

Recent findings suggest that not only the lack of physical activity, but also prolonged times of sedentary behaviour where major locomotor muscles are inactive, significantly increase the risk of chronic diseases. The purpose of this study was to provide details of quadriceps and hamstring muscle inactivity and activity during normal daily life of ordinary people. Eighty-four volunteers (44 females, 40 males, 44.1±17.3 years, 172.3±6.1 cm, 70.1±10.2 kg) were measured during normal daily life using shorts measuring muscle electromyographic (EMG) activity (recording time 11.3±2.0 hours). EMG was normalized to isometric MVC (EMG(MVC)) during knee flexion and extension, and inactivity threshold of each muscle group was defined as 90% of EMG activity during standing (2.5±1.7% of EMG(MVC)). During normal daily life the average EMG amplitude was 4.0±2.6% and average activity burst amplitude was 5.8±3.4% of EMG(MVC) (mean duration of 1.4±1.4 s) which is below the EMG level required for walking (5 km/h corresponding to EMG level of about 10% of EMG(MVC)). Using the proposed individual inactivity threshold, thigh muscles were inactive 67.5±11.9% of the total recording time and the longest inactivity periods lasted for 13.9±7.3 min (2.5-38.3 min). Women had more activity bursts and spent more time at intensities above 40% EMG(MVC) than men (p<0.05). In conclusion, during normal daily life the locomotor muscles are inactive about 7.5 hours, and only a small fraction of muscle's maximal voluntary activation capacity is used averaging only 4% of the maximal recruitment of the thigh muscles. Some daily non-exercise activities such as stair climbing produce much higher muscle activity levels than brisk walking, and replacing sitting by standing can considerably increase cumulative daily muscle activity.

Concepts: Physical exercise, Arithmetic mean, Mode, Extension, Thigh, Knee, Muscle, Electromyography

177

It has recently been recommended that sedentary behavior be defined as sitting or reclining activities expending less than 1.5 metabolic equivalents (METs), which is distinct from the traditional viewpoint based on insufficient moderate-vigorous activity or formal exercise. This study was designed to determine the energy expenditure associated with common sedentary behaviors. Twenty-five African American adults (BMI 27.8±5.5) participated in the metabolic chamber study. Participants entered the metabolic chamber in the morning and their basal metabolic rate was estimated. They were fed breakfast and then engaged in four different sedentary behaviors sequentially, lasting 30 minutes each. The activities included reclining, watching TV, reading, and typing on a computer. In the afternoon, the participants were fed lunch and then the activities were repeated. The results show that the energy expenditure values between the morning and afternoon sessions were not significantly different (p = .232). The mean energy expenditure of postprandial reclining (0.97 METs) was slightly, but significantly, lower than postprandial watching TV (p = .021) and typing (p<.001). There were no differences in energy cost (1.03-1.06 METs) between the seated (i.e., reading, typing, watching TV) sedentary activities. The energy expenditure of several common sedentary behaviors was approximately 1.0 METs in the postprandial state. The results support the conclusion that the average energy cost of common sedentary behaviors is narrowly banded around 1.0 METs in the postprandial state.

Concepts: Costs, Arithmetic mean, Cost, Metabolism, Energy, Metabolic equivalent, Basal metabolic rate

170

BACKGROUND: Excessive shoe heel abrasion is of concern to patients, parents and shoe manufacturers, but little scientific information is available. The purpose of this study was to describe the phenomenon in a group of infantry recruits performing similar physical activity, and search for biomechanical factors that might be related. METHODS: Seventy-six subjects (median age 19) enrolled. Pre-training parameters measured included height, weight, tibial length, foot arch height and foot progression angle. Digital plantar pressure maps were taken to calculate arch indexes. Shoe heel abrasion was assessed manually after 14 weeks of training with different-sized clock transparencies and a calliper. RESULTS: Outsole abrasion was posterolateral, averaging 12 degrees on each shoe. The average heel volume that was eroded was almost 5 cm3. The angle of maximum wear was related to right foot progression angle (r = 0.27, p = 0.02). Recruits with lateral ankle sprains had higher angles of maximal abrasion (17[degree sign] versus 10[degree sign], p = 0.26) and recruits with lateral heel abrasion had more lateral ankle sprains (14% versus 3%, p = 0.12). CONCLUSION: While shoe heel wear affects many people, very little has been done to measure it. In this study in healthy subjects, we found the main abrasion to be posterolateral. This seems to be related to foot progression angle. It was not related to hindfoot valgus/varus or other factors related to subtalar joint motion. These findings do not warrant modification of subtalar joint motion in order to limit shoe heel abrasion.

Concepts: Angle, Pes cavus, Subtalar joint, Arithmetic mean, Ankle, Length, Tarsus, Foot

169

OBJECTIVES: To investigate the association between occupational contamination and exposure levels to antineoplastic drugs and the application of control measures in a hospital work environment. Methods : Wipe samples of equipments were collected at a hospital in Osaka Prefecture, Japan, from 2007 to 2011. These samples were subjected to measurements of cyclophosphamide (CP), gemcitabine (GEM), platinum-containing drugs (Pt), and fluorouracil (5FU). Additionally, 24-h urine samples were collected from pharmacists who handled antineoplastic drugs, which were analyzed for CP and alpha-fluoro-beta-alanine (AFBA). The application of control measures was scored according to a checklist, which consisted of the following five items: safety equipment and maintenance, training and documentation, devices for safe handling, personal protective equipment, and emergency care. The aim was to obtain a score of 80%. Results : The median CP, GEM, and 5FU concentrations of all wipe samples were significantly lower during the period when the mean score was >80% (attainment period) versus when the mean score was ≤80% (nonattainment period; all P < 0.001, Mann-Whitney's U-test). Additionally, the median urinary CP and AFBA concentrations of pharmacists during the attainment period tended to be lower than that of those during the nonattainment period (P = 0.061 and 0.061, respectively, using Mann-Whitney's U-test). Conclusions : Contamination and levels of exposure to antineoplastic drugs decreased with a score higher than 80%. The scores of the items on the checklist appeared to adequately reflect the condition of the control measures, as increases in all five items were associated with reductions in the contamination by and levels of exposure to all drugs.

Concepts: Prefectures of Japan, Personal protective equipment, Pharmacy, Osaka Prefecture, Protection, Scores, Arithmetic mean, Occupational safety and health

167

Summary This paper explores the hypothesis that gender attitude scales (which measure the degree of equity in gender attitudes) are associated with contraceptive use. Four hundred male and female respondents (200 couples) were interviewed using a pre-tested, structured questionnaire. Analyses included comparisons of means and prevalence rates on gender equity indicators, other related factors and socio-demographic characteristics; t-tests to compare mean scores on each gender scale for wives and husbands to identify any significant differences; chi-squared tests to compare associations between individual attributes, attitudes and contraceptive use; and multivariate logistic regression to examine associations between each gender scale and contraceptive use. The findings revealed that, on average, wives endorsed more inequitable gender attitudes compared with husbands on all gender attitude scales. For wives, more equitable gender attitudes were positively associated with contraceptive use. For husbands, the role of gender attitudes had no significant association with wives' reported contraceptive use. Family planning programmes that aim to challenge inegalitarian gender norms should not overlook women in their efforts since both men and women often accept and support inequality in a social system and, in some cases, it may be women’s gender attitudes that most influence family planning decisions.

Concepts: Family planning, Questionnaire, Arithmetic mean, Male, Female, Gender role, Woman, Gender

159

Objective. RA and axial SpA have an important impact on patients' lives. The objective of this study was to explore the reporting of different aspects of that impact in publications, with a focus on differences between diseases and over time.Methods. A systematic literature review retrieved all articles reporting on the life impact of RA or axial radiographic SpA in adults published within the last 10 years and issued from European research. The data were classified into physical impact (including pain, functional assessment and fatigue), psychological impact (including psychological distress and coping) and social impact (including relationships, family and social life). The number of articles published over time was analysed by linear regression.Results. In all, 1352 abstracts were screened and 149 publications (40 056 patients) were analysed: 129 articles (86.5%) concerned RA and 16 (10.7%) concerned axial SpA. The mean number of articles reporting on the physical aspects of impact was 11.4 (s.d. 4.8) per 2-year period, but increased more than 2-fold (from 7 articles in 2001-3 to 15 in 2010-11), in particular due to recent publications on fatigue, whereas the number of articles on psychological aspects [mean 12.4 (s.d. 4.0)] decreased markedly after 2006. Publications reporting on social aspects [mean 8.2 (s.d. 4.1)] remained globally stable.Conclusion. In the era of biologics, there is an interest in the patient-perceived life impact of RA and axial SpA in the European literature, but the impact of RA has been the subject of greater exploration. There are clearly trends over time in the reporting of impact.

Concepts: Rheumatology, Subject, Psoriatic arthritis, Academic publishing, Publishing, Arthritis, Arithmetic mean, Rheumatoid arthritis

158

This study investigated the energy intake and expenditure of professional adolescent academy-level soccer players during a competitive week. Over a seven day period that included four training days, two rest days and a match day, energy intake (self-reported weighed food diary and 24-h recall) and expenditure (tri-axial accelerometry) were recorded in 10 male players from a professional English Premier League club. The mean macronutrient composition of the dietary intake was 318 ± 24 g·day(-1) (5.6 ± 0.4 g·kg(-1) BM) carbohydrate, 86 ± 10 g·day(-1) (1.5 ± 0.2 g·kg(-1) BM) protein and 70 ± 7 g·day(-1) (1.2 ± 0.1 g·kg(-1) BM) fats, representing 55% ± 3%, 16% ± 1%, and 29% ± 2% of mean daily energy intake respectively. A mean daily energy deficit of -1302 ± 1662 kJ (p = 0.035) was observed between energy intake (9395 ± 1344 kJ) and energy expenditure (10679 ± 1026 kJ). Match days (-2278 ± 2307 kJ, p = 0.012) and heavy training days (-2114 ± 2257 kJ, p = 0.016) elicited the greatest deficits between intake and expenditure. In conclusion, the mean daily energy intake of professional adolescent academy-level soccer players was lower than the energy expended during a competitive week. The magnitudes of these deficits were greatest on match and heavy training days. These findings may have both short and long term implications on the performance and physical development of adolescent soccer players.

Concepts: Developmental psychology, Weighted mean, Economics, Deficit spending, Arithmetic mean, Deficit, Cost, Premier League

153

Polycyclic aromatic hydrocarbons (PAHs) were analyzed for 136 indoor dust samples collected from Guizhou province, southwest of China. The ∑18PAHs concentrations ranged from 2.18 μg•g-1 to 14.20 μg•g-1 with the mean value of 6.78 μg•g-1. The highest Σ18PAHs concentration was found in dust samples from orefields, followed by city, town and village. Moreover, the mean concentration of Σ18PAHs in indoor dust was at least 10% higher than that of outdoors. The 4-6 rings PAHs, contributing more than 70% of ∑18PAHs, were the dominant species. PAHs ratios, principal component analysis with multiple linear regression (PCA-MLR) and hierarchical clustering analysis (HCA) were applied to evaluate the possible sources. Two major origins of PAHs in indoor dust were identified as vehicle emissions and coal combustion. The mean incremental lifetime cancer risk (ILCR) due to human exposure to indoor dust PAHs in city, town, village and orefield of Guizhou province, China was 6.14×10-6, 5.00×10-6, 3.08×10-6, 6.02×10-6 for children and 5.92×10-6, 4.83×10-6, 2.97×10-6, 5.81×10-6 for adults, respectively.

Concepts: Arithmetic mean, Regression analysis, Aromaticity, Principal component analysis, Yunnan, Naphthalene, Southwest China, Polycyclic aromatic hydrocarbon