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1.
In developing countries like India, where the incidence of protein-calorie malnutrition is high and mechanization is at a minimum, human labor provides much of the power for physical activity. This study presents anthropometric measurements, somatotypes, food intakes, energy expenditures, and work outputs of Oraon agricultural laborers of the Jalpaiguri district, West Bengal, in an attempt to identify the factors that predict high work productivity. Specifically, this study investigates 1) the relationship between morphological variation (anthropometric measurements and somatotype) and work productivity, 2) the nature and extent of the relationship between nutritional status and work productivity, and 3) the best predictor variables of work output. Classification of groups on the basis of median values of work output show that in the aggregate, the high productive groups are significantly younger than low-productive groups in both sexes. Before age-adjustment, the high productive groups show higher mean values of a few body dimensions, though these differ by sex, and both males and females exhibit a normal range of blood pressure and pulse rate values. Mean values of grip strength and back strength are higher in high-output men and women. Mean values of both food intake and energy expenditure are also higher among men in high-output groups, with only food intake higher in high-output women. However, after eliminating the effects of age, the differences between low-productive groups and high-productive groups in most of the variables are not significant. Productivity predictors in males consist of age, food intake and chest girth (inhalation). Females, on the other hand, show age and grip strength (left) as work output predictors.  相似文献   

2.
Objective: To disclose the possible relationship between habitual tea consumption and changes in total body fat and fat distribution in humans. Research Methods and Procedures: A cross‐sectional survey of 1210 epidemiologically sampled adults (569 men and 641 women) were enrolled in our study. Tea consumption and other lifestyle characteristics were obtained by structured questionnaires. Percent body fat (BF%) was measured using bioelectrical impedance analysis. Body fat distribution was assessed using waist‐to‐hip ratio (WHR). Results: Among the 1103 analyzed subjects, 473 adults (42.9%) consumed tea once or more per week for at least 6 months. The habitual tea drinkers were male‐dominant, more frequently current smokers, and alcohol or coffee drinkers than the nonhabitual tea drinkers. Habitual tea drinkers for more than 10 years showed a 19.6% reduction in BF% and a 2.1% reduction in WHR compared with nonhabitual tea drinkers. The multiple stepwise regression models revealed that men, older age, higher BMI, and current smokers were positive factors for BF% and WHR. In contrast, longer duration of habitual tea consumption and higher total physical activity were negative factors for BF%. Longer duration of habitual tea consumption, higher socioeconomic status, and premenopausal status were negative factors for WHR. Discussion: An inverse relationship may exist among habitual tea consumption, BF%, and body fat distribution, especially for subjects who have maintained the habit of tea consumption for more than 10 years.  相似文献   

3.
Over the past 23 years (1990 to 2012), French beef cattle farms have expanded in size and increased labour productivity by over 60%, chiefly, though not exclusively, through capital intensification (labour–capital substitution) and simplifying herd feeding practices (more concentrates used). The technical efficiency of beef sector production systems, as measured by the ratio of the volume value (in constant euros) of farm output excluding aids to volume of intermediate consumption, has fallen by nearly 20% while income per worker has held stable thanks to subsidies and the labour productivity gains made. This aggregate technical efficiency of beef cattle systems is positively correlated to feed self-sufficiency, which is in turn negatively correlated to farm and herd size. While volume of farm output per hectare of agricultural area has not changed, forage feed self-sufficiency decreased by 6 percentage points. The continual increase in farm size and labour productivity has come at a cost of lower production-system efficiency – a loss of technical efficiency that 20 years of genetic, technical, technological and knowledge-driven progress has barely managed to offset.  相似文献   

4.
The relationships between basic and applied agricultural R&D, developed and developing country R&D and between R&D, extension, technology and productivity growth are outlined. The declining growth rates of public R&D expenditures are related to output growth and crop yields, where growth rates have also fallen, especially in the developed countries. However, growth in output value per hectare has not declined in the developing countries and labour productivity growth has increased except in the EU. Total factor productivity has generally increased, however it is measured. The public sector share of R&D expenditures has fallen and there has been rapid concentration in the private sector, where six multinationals now dominate. These companies are accumulating intellectual property to an extent that the public and international institutions are disadvantaged. This represents a threat to the global commons in agricultural technology on which the green revolution has depended. Estimates of the increased R&D expenditures needed to feed 9 billion people by 2050 and how these should be targeted, especially by the Consultative Group on International Agricultural Research (CGIAR), show that the amounts are feasible and that targeting sub-Saharan Africa (SSA) and South Asia can best increase output growth and reduce poverty. Lack of income growth in SSA is seen as the most insoluble problem.  相似文献   

5.
The experimental research showed that the worker satisfaction-productivity and the worker job attitudes-productivity relationships were stronger for the individuals who had exhibited a higher growth need strength (GNS) than the subjects with a lower GNS in a repetitive production task enriched by the provision of production standards and feedback. Under high GNS, the correlation coefficient values between worker satisfaction and productivity in terms of quantity output were found to be statistically significant, whereas none of the values were significant under low GNS. The correlation coefficient values between worker job attitudes and productivity in terms of both quantity and quality output were significant under high GNS, whereas under low GNS none of the values were significant.  相似文献   

6.
Body size reveals a plethora of life-history, ecological, and evolutionary information about a species. It plays a critical role in success or failure during competitive, reproductive, or predator–prey interactions. Typically, there is a negative relationship between body size and population density in natural populations and communities. I analysed this relationship within and among multiple populations of two prominent monogenean parasites (>90% prevalence) on Lepomis macrochirus in three lakes in New Jersey (USA), using multiple regression models. To elucidate the causes and benefits of this relationship, I also measured host body condition via a regression index, and reproductive output of the parasite community by measuring parasite eggs shed from the host. The relationship between body size and density of infrapopulations (parasites of a single species on a single host) was positive, and the strength of this relationship for both species depended on which lake they occupied, indicating the potential for Allee effects. This relationship persists at the infracommunity level, where there was a similar positive relationship between a community weighted mean body size and density. However, this relationship did not result in greater reproductive success as measured by infracommunity egg production per individual per 24 h or egg size. The cause of this relationship also remains elusive; it was not explained by host condition or age. The results suggest that there is either no reproductive advantage to this increase in body size or the advantage conferred was not related to these measured fitness components. These findings indicate that researchers should be cautious using body size as a proxy for fitness or reproduction, while also raising further questions about the nature of the relationship between parasites on a host and that between those parasites and the host.  相似文献   

7.
Aim The goal of this paper is to examine the relationships between body size, biomic specialization and range size in the African large mammals, which are defined as all the African species corresponding to the orders Primates, Carnivora, Proboscidea, Perissodactyla, Hyracoidea, Tubulidentata, Artiodactyla and Pholidota. Location The study used the large mammal assemblage from Africa. Methods The degree of biomic specialization of African large mammals is investigated using the biomic specialization index (BSI) for each mammal species, based on the number of biomes it inhabits. Range size for each species is measured as the latitudinal extent of the geographical distribution of the species. We have analysed our data using both conventional cross‐species analyses and phylogenetically independent contrasts. Results There is a polygonal relationship between species biomic specialization and body size. While small and large species are biomic specialists, medium‐sized species are distributed along the whole range of biomic specialization. The latitudinal extent–body size relationship is approximately triangular. Small‐bodied species may have either large or small ranges, whereas large‐bodied ones have only large ranges. A positive correlation between latitudinal extent and biomic specialization is evident, although their relationship is better described as triangular. Main conclusions We found a polygonal relationship between species biomic specialization and body size, which agrees with previous arguments that small‐bodied species have more limited dispersal and, therefore, they may come to occupy a lesser proportion of their potential inhabitable biomes. On the other hand, large‐bodied species are constrained to inhabit biomes with a high productivity. A polygonal relationship between species latitudinal extent and body size in African large mammals agrees with previous studies of the relationship between range size and body size in other continents. The independent study of the macroecological pattern in biomic specialization highlights different factors that influence the body size–range size relationship. Although body size is usually implicated as a correlate of both specialization and geographical range size in large mammals, much of the variation in these variables cannot be attributed to size differences but to biome specific factors such as productivity, area, history, etc.  相似文献   

8.
Motor skill performance and physical activity in preschool children   总被引:3,自引:0,他引:3  
Children with better-developed motor skills may find it easier to be active and engage in more physical activity (PA) than those with less-developed motor skills. The purpose of this study was to examine the relationship between motor skill performance and PA in preschool children. Participants were 80 three- and 118 four-year-old children. The Children's Activity and Movement in Preschool Study (CHAMPS) Motor Skill Protocol was used to assess process characteristics of six locomotor and six object control skills; scores were categorized as locomotor, object control, and total. The actigraph accelerometer was used to measure PA; data were expressed as percent of time spent in sedentary, light, moderate-to-vigorous PA (MVPA), and vigorous PA (VPA). Children in the highest tertile for total score spent significantly more time in MVPA (13.4% vs. 12.8% vs. 11.4%) and VPA (5% vs. 4.6% vs. 3.8%) than children in middle and lowest tertiles. Children in the highest tertile of locomotor scores spent significantly less time in sedentary activity than children in other tertiles and significantly more time in MVPA (13.4% vs. 11.6%) and VPA (4.9% vs. 3.8%) than children in the lowest tertile. There were no differences among tertiles for object control scores. Children with poorer motor skill performance were less active than children with better-developed motor skills. This relationship between motor skill performance and PA could be important to the health of children, particularly in obesity prevention. Clinicians should work with parents to monitor motor skills and to encourage children to engage in activities that promote motor skill performance.  相似文献   

9.
This paper examines the relationship between obesity and labour market success in Finland, using various indicators of individual body composition along with body mass index (BMI). Weight, height, fat mass and waist circumference are measured by health professionals. We find that only waist circumference has a negative association with wages for women, whereas no obesity measure is significant in the linear wage models for men. However, all measures of obesity are negatively associated with women's employment probability and fat mass is negatively associated with men's employment probability. We also find that the use of categories for waist circumference and fat mass has a substantial influence on the results. For example, the category for high fat mass is associated with roughly 5.5% lower wages for men. All in all, the results indicate that in the absence of measures of body composition, there is a risk that labour market penalties associated with obesity are measured with bias.  相似文献   

10.
Over the past 100 years, the French livestock sector has experienced significant intensification that has occurred in different ways across the country. Specifically, France has changed from a homogeneous state with most of the agricultural area covered by grasslands and a uniform distribution of animals, to a heterogeneous state characterised by an uneven distribution of grasslands, livestock numbers and livestock species. Studying the dynamics of this change is fundamental to the identification of drivers that shaped the various intensification trajectories and led to these different states, as well as to the prediction of future changes. Hence, the objective of this study was to characterise the trajectories undertaken by the French livestock sector to understand the intensification process and the role of socioeconomic, land use and production-related factors. A set of 10 indicators was employed to analyse the main changes between 1938 and 2010, using principal component analysis followed by a clustering of the 88 French departments. Between 1938 and 2010, significant increases in farm size, mechanisation, labour productivity and the stocking rates of monogastrics enabled the French livestock sector to double its production. The most important changes involved mechanisation (with the number of tractors per hectare (ha) rising from 0.0012 to 0.0053), labour productivity (improving from 8.6 to 35.9 ha/worker), livestock production (e.g. milk production increasing from 758 to 1856 l/ha of fodder area) and stocking rates (rising from 0.57 to 0.98 livestock units (LU) per ha). The increased heterogeneity apparent in the patterns of change throughout France’s departments was captured by clustering four trajectories. Two trajectories were formed by departments that experienced strong specialisation towards livestock production, with one type mainly orientated towards high-intensive dairy, poultry and pig landless production systems, and a second type orientated towards extensive beef grazing production systems. Another trajectory corresponded to departments that specialised in crop production with high labour productivity; mixed crop-livestock systems were still maintained at the margins of this group of departments. The fourth trajectory corresponded to the lowest livestock population and productivity levels. The increase in mechanisation during the period was important but uniform, with no significant differences between the trajectories. This typology of intensification trajectories will enable the targeting of specific areas in which the detrimental impacts of livestock intensification require mitigation and provide guidance for future livestock sector developments.  相似文献   

11.
Central nervous, neuromuscular, cardiovascular systems and high psychic functions: thinking, attention and memory in assemblers of electric equipment have been studied in complex. These studies have revealed that high labour productivity is achieved due to the high functional stress of physiological systems of the organism. In this case functions both specific and nonspecific for the local physical work are activated. High-efficient activity is followed by mobilization of the psychophysiological functions, interfunctional relations being intensified.  相似文献   

12.
The purpose of this study was to investigate the moderator effects of autonomous motivation on the relationship between subjective well-being and physical health. Using a cluster sampling approach 486 students (403 female and 83 male students) were included in this study. Subjective well-being, physical health and autonomous motivation were determined by self-report measures. Data were analysed using hierarchical regression analysis and analysis of variance. The results show that high self-determination moderates the relationship between high subjective well-being and physical health. Accordingly, the best physical health was reported by participants who had high level of subjective well-being and whose behaviours were self-determined. Additional analyses have shown that the moderating effect of self-determination is based on the moderational impact of autonomous motives and not the controlling ones. Additionally, whether autonomous motivation moderates the relationship between components of subjective well-being and physical health was also tested. The findings have shown that autonomous motives moderate relationship between physical health and one component of well-being, positive affect. Consequently, a good physical health was found among participants with high positive affect and behaviours regulated by high degree of autonomous motives. Conclusion which can be drawn from these findings is that if an individual behaves autonomously then it can contribute to positive mind—body influences and support their own health.  相似文献   

13.
Surplus accounting is a method for evaluating trends in how a firm’s productivity factors (intermediate inputs, capital, land, labour) are performing and how the productivity gains are redistributed between agents in the economy. Here the surplus accounting method was applied on a database of 164 Charolais-area suckler cattle farms running from 1980 to 2015. Over this 36-year period – with differences per sub-period – the cumulative productivity surplus (PS) increased at a low rate of +0.17%/year (i.e. cumulative volume of outputs produced increased slightly more than cumulative volume of inputs used). This timid increase in PS is linked to the constant expansion in labour productivity whereas other factor productivities have shrunk. The observable period-wide macrotrends are that commercial farm businesses struggle to protect their revenues, we also observe a slight fall in input prices, land rent and financing costs, and a huge climb in direct support-policy payments. The bulk of the cumulative economic surplus has been captured downstream – 64% downstream of the cattle value chain as a drop in prices, and 22% downstream of other value chains (chiefly cereals). It emerges that the productivity gains in beef cattle farming mostly benefit the downstream value chain (packers–processors, distributors and consumers), whereas it is mainly government money backing this drop in prices of agricultural output. Here we see the principal of the 1992 ‘MacSharry’ reform at work, with a transfer from the taxpayer through direct support-policy payments through to the consumer via lower prices. The simple fact that farmers’ incomes are stagnating is a clear indication that they are net losers in this distribution of productivity gains, despite the improvement in labour factor productivity.  相似文献   

14.
Jan Ryser 《Oecologia》1989,78(2):264-268
Summary The consequences of reproduction for body weight, growth and survival were studied in a Swiss population of the explosive breeder, Rana temporaria. Males and females continuously loss weight in the range of 0.5% of total body weight per day from the breeding migration throughout May. Females also lost about 33% (1983) and 29% (1984) due to spawning. In addition to this significant year-to-year variation, there was also considerable individual variation in reproductive output. Skeletochronological techniques indicated that breeding male or female frogs experienced a growth reduction of several millimeters relative to non-breeding frogs of the same body size. There was no relationship between an individual female's reproductive output in consecutive years or with her subsequent growth or survival. It was concluded that weight loss is caused by a seasonally elevated metabolism in combination with a lack of feeding and represents a basic energetic cost of reproduction, resulting in lowered growth. Individual variation in relative reproductive output is mostly environmentally induced and is not an expression of different reproductive strategies. This may explain the lack of trade-offs that are predicted by the cost-of-reproduction-hypothesis.  相似文献   

15.
The consumption of green tea has been associated with cardiovascular and metabolic diseases. There have been some studies on the influence of green tea on the mineral status of obese subjects, but they have not yielded conclusive results. The aim of the present study is to examine the effects of green tea extract on the mineral, body mass, lipid profile, glucose, and antioxidant status of obese patients. A randomized, double-blind, placebo-controlled study was conducted. Forty-six obese patients were randomly assigned to receive either 379?mg of green tea extract, or a placebo, daily for 3?months. At baseline, and after 3?months of treatment, the anthropometric parameters, blood pressure, and total antioxidant status were assessed, as were the levels of plasma lipids, glucose, calcium, magnesium, iron, zinc, and copper. We found that 3?months of green tea extract supplementation resulted in decreases in body mass index, waist circumference, and levels of total cholesterol, low-density cholesterol, and triglyceride. Increases in total antioxidant level and in zinc concentration in serum were also observed. Glucose and iron levels were lower in the green tea extract group than in the control, although HDL-cholesterol and magnesium were higher in the green tea extract group than in the placebo group. At baseline, a positive correlation was found between calcium and body mass index, as was a negative correlation between copper and triglycerides. After 3?months, a positive correlation between iron and body mass index and between magnesium and HDL-cholesterol, as well as a negative correlation between magnesium and glucose, were observed. The present findings demonstrate that green tea influences the body's mineral status. Moreover, the results of this study confirm the beneficial effects of green tea extract supplementation on body mass index, lipid profile, and total antioxidant status in patients with obesity.  相似文献   

16.
While wage labour and money have received much anthropological attention, the same cannot be said of wages themselves – actual banknotes and coins distributed in workforces. This article traces wages' social productivity among farm workers on the Zimbabwean‐South African border. In this migrant‐labour setting, money's form matters. Because currency objects are physically the same, it is difficult for workers to store them in an insecure environment, leading them to turn to one another. As they manage their earnings, workers attempt to establish themselves as social persons while maintaining future options in uncertain circumstances. Workforce ties both shape and are constituted by flows of cash and the rhythms and circuits of the wage. Seen in terms of form, wages are highly personal – the very stuff of sociality.  相似文献   

17.
Dispersal of organisms can influence the relationship between beta‐diversity and regional productivity in heterogeneous environments. However, many ecosystems are also linked by fluxes of stressors, with an unknown influence on this relationship. In this study, we assess the relationship between beta‐diversity (measured as Bray–Curtis dissimilarity) and regional productivity (measured as biovolume) under various levels of a stressor flux in meta‐ecosystems that were composed of two marine micro‐algae communities. We created heterogeneity by exposing one of the two communities to a herbicide and manipulated regional diversity by applying a dispersal gradient, which decreased beta‐diversity. We applied four stressor flux levels, which homogenized the herbicide concentration between the communities over time. The stressor flux changed the relationship between beta‐diversity and regional productivity by changing the effect of dispersal on regional productivity. In absence of the stressor flux, the relationship between beta‐diversity and regional productivity was mostly not significant, but positive at the end of the experiment. This positive relationship was generated by a negative effect of dispersal on regional productivity, probably because dispersal disrupted local dynamics by removing organisms from the most‐productive unstressed community. In presence of the stressor flux, the relationship between beta‐diversity and regional productivity was often negative as dispersal now increased regional productivity. Dispersal increased regional productivity by increasing the productivity of the stressed community. This positive effect was stronger in the presence than in the absence of the stressor flux because the stressor flux reduced the concentration of the herbicide in the stressed community, where it facilitated recovery. Our study shows that stressor fluxes can strongly interact with the effects of dispersal on productivity and thus influence diversity–productivity relationships.  相似文献   

18.
Doing the right thing: Ants, honeybees and naked mole-rats   总被引:1,自引:0,他引:1  
Traditionally the division of labour in social insects has been divided into two types: physical and temporal polyethism. New theoretical models indicate that temporal polyethism may be an emergent property rather than an organizational principle. Current research is revealing the relationship between temporal polyethism and the role of nonspecialized individuals within species of physically polymorphic social insects.  相似文献   

19.
【背景】福寿螺是危害极其严重的入侵我国的水生生物,目前利用相关分析、通径分析对福寿螺形态性状变异的研究较少。【方法】随机采集7个地区的福寿螺(雌雄比例差别很大),测量其壳高、壳宽、口宽、层高4个形态性状和体质量,采用相关分析、通径分析方法计算福寿螺的各形态指标变异系数、相关系数和通径系数,剔除对体质量影响不显著的指标,确定每个地区与体质量最相关的指标。【结果】除惠州之外,其余地区福寿螺的壳高和壳宽与体质量的相关性较高,且口宽与壳高共同作用对体质量的直接影响很大。【结论与意义】此结果为研究不同生境、不同温度下福寿螺的形态性状变异程度奠定了基础,同时为福寿螺形态鉴定、分类及其灾害预测预报提供了基础数据。  相似文献   

20.

Need to Assess the Skill of Ecosystem Models

Accelerated changes to global ecosystems call for holistic and integrated analyses of past, present and future states under various pressures to adequately understand current and projected future system states. Ecosystem models can inform management of human activities in a complex and changing environment, but are these models reliable? Ensuring that models are reliable for addressing management questions requires evaluating their skill in representing real-world processes and dynamics. Skill has been evaluated for just a limited set of some biophysical models. A range of skill assessment methods have been reviewed but skill assessment of full marine ecosystem models has not yet been attempted.

Northeast US Atlantis Marine Ecosystem Model

We assessed the skill of the Northeast U.S. (NEUS) Atlantis marine ecosystem model by comparing 10-year model forecasts with observed data. Model forecast performance was compared to that obtained from a 40-year hindcast. Multiple metrics (average absolute error, root mean squared error, modeling efficiency, and Spearman rank correlation), and a suite of time-series (species biomass, fisheries landings, and ecosystem indicators) were used to adequately measure model skill. Overall, the NEUS model performed above average and thus better than expected for the key species that had been the focus of the model tuning. Model forecast skill was comparable to the hindcast skill, showing that model performance does not degenerate in a 10-year forecast mode, an important characteristic for an end-to-end ecosystem model to be useful for strategic management purposes.

Skill Assessment Is Both Possible and Advisable

We identify best-practice approaches for end-to-end ecosystem model skill assessment that would improve both operational use of other ecosystem models and future model development. We show that it is possible to not only assess the skill of a complicated marine ecosystem model, but that it is necessary do so to instill confidence in model results and encourage their use for strategic management. Our methods are applicable to any type of predictive model, and should be considered for use in fields outside ecology (e.g. economics, climate change, and risk assessment).  相似文献   

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