Physical limitations and musculoskeletal complaints associated with work in unusual or restricted postures: a literature review

INTRODUCTION: The vast majority of ergonomics research has addressed the demands of work in standing or sitting postures, and understandably so. However, many workers (e.g., underground miners, aircraft baggage handlers, plumbers, agricultural workers, mechanics, and others) are often required to adopt postures such as kneeling, stooping, squatting, or lying down for significant periods of the workday. METHOD: A literature search was performed using the ISI Web of Science database (for years 1980-2004). Articles retrieved from this search were evaluated in terms of relevance to assessing physical capabilities of workers in these postures and/or the musculoskeletal epidemiology associated with these postures. RESULTS: Work in unusual and restricted postures was associated with significantly higher rates of musculoskeletal complaints compared to workers not adopting these postures in epidemiology studies (Odds Ratios ranging from 1.13 to 13). Some studies suggested a dose-response relationship, with longer exposures leading to increased musculoskeletal complaints. Physical strength and psychophysical lifting capacity vary significantly as unusual or restricted postures are adopted, with lower lifting capacities evident in the kneeling, squatting, and lying positions. CONCLUSIONS: Workers who adopt unusual or restricted postures appear to be at higher risk of musculoskeletal complaints and often exhibit reduced strength and lifting capacity. Research needs in this area include improved exposure assessment tools, studies of intervention effectiveness, adaptations of the body in response of work in unusual postures, and elucidation of relevant injury pathways. IMPACT ON INDUSTRY: Workers who adopt unusual or restricted postures in their work often experience higher musculoskeletal injury rates. If awkward postures cannot be eliminated in the workplace, jobs should be designed in accordance with the reduced strength and lifting capabilities observed in these postures.     

Ecotypic differentiation in the marine diatom Skeletonema costatum: influence of light intensity on the photosynthetic apparatus

Three genetically distinct clones of Skeletonema costatum (Grev.) Cleve were grown at 20°C under high (274 E m^-2 s^-1) and low (27 E m^-2 s^-1) light conditions and their photoadaptive photosynthetic responses compared. When all three clones were grown under low light, pigment analyses and fluorescence excitation spectra demonstrated that the accessory pigments, chlorophyll c and fucoxanthin, became more important in light-harvesting compared to chlorophyll a. Photosynthetic unit sizes increased for Photosystems I and II in low light, but photosynthesis vs irradiance characteristics were not reliable predictors of photosynthetic unit features. Fluorescence excitation spectra and photosynthesis vs irradiance (P-I) relationships indicated that changes in energy transfer occurred independent of changes in pigment content. Large increases in accessory pigment content were not accompanied by large increases in excitation from these pigments. Changes in energy transfer properties were as important as changes in PSU size in governing the photoadaptive responses of S. costatum. When the three clones were grown under identical conditions, each had a separate and distinct pattern of photoadaptation. Significant differences among clones were found for pigment ratios, photosynthetic unit sizes for Photosystems I and II and efficiency of energy transfer between pigments. These strikingly different photoadaptive strategies among clones may partially account for the great ecological success of the diatom species. This is the first quantitative investigation of the importance of both chlorophyll c and fucoxanthin to the adaptive responses of diatoms to light intensity, and represents the most complete characterization of the photoadaptive responses of a single species of marine phytoplankter to differences in light environment.     

Measurements and modelling of cloudwater deposition to moorland and forests

The objective of the study was to measure the size dependence of cloudwater deposition and associated average ionic fluxes to vegetated surfaces. Measurements were made over a forest canopy at Dunslair heights in south Scotland and a moorland site, Great Dun Fell, in northern England. Measurements were made using the gradient and eddy correlation techniques. Eddy correlation measurements were made using an ultrasonic anemometer, a Knollenberg forward scattering spectrometer probe (to measure liquid water fluxes and fluxes of droplets in 1 microm size intervals) and a GSI particulate volume monitor (to measure liquid-water fluxes). Measurements were made at Great Dun Fell of the size dependence of droplet deposition velocity, using the gradient technique with two Knollenberg probes. Simultaneous gradient and eddy correlation measurements were also made at Great Dun Fell of average cloud-water fluxes, together with chemical analysis of cloud water composition, using a continuous analysis system. At Dunslair Heights, eddy correlation measurements were made using both the Knollenberg and Gerber Scientific Instruments (GSI) probes, while simultaneous gradient measurements using two GSI probes were also attempted. Samples of cloud water were collected at Dunslair Heights, using passive string collectors for chemical analysis by ion chromatography. The major findings of the study were: 1. The droplet deposition velocities measured by the two techniques were similar. 2. The deposition velocities were a strong function of droplet size. Considerable resistance to deposition was evident for droplets of less than 5 microm radius. Deposition velocities for particles from about 6 to 8 microm exceeded those for momentum. 3. Except when the droplets were very small or the winds very light, bulk cloud-water deposition velocities were about 80% or more of the momentum deposition velocities to forests.     

INPUTS OF COPPER‐BASED CROP PROTECTANTS TO COASTAL CREEKS FROM PASTICULTURE RUNOFF1

ABSTRACT: Inputs of copper‐based crop protectants from tomato fields grown under plastic mulch agriculture (plasticulture) to an estuarine creek were investigated. Copper was measured in runoff from diverse land‐uses including conventional agriculture, plasticulture, residences, and natural areas. Water column and sediment copper concentrations were measured in plasticulture and control (nonagriculture) watersheds. Copper concentrations in plasticulture‐impacted creeks exceeded background levels episodically. High concentrations occurred during or immediately after runoff‐producing rains. Concentrations of 263 μg/L total copper and 126 μg/L dissolved copper were measured in a tidal creek affected by plasticulture; concentrations exceeded the shellfish LC₅₀ values and the water quality criteria of 2.9 μg/L dissolved copper. Control watersheds indicated background water column levels of ≤ 4 μg/L dissolved copper with similar copper levels during periods with and without rain. The copper concentrations in tomato plasticulture field runoff itself contained up to 238 μg/L dissolved copper. Copper concentrations in runoff from other land‐uses were less than 5 μg/L dissolved copper. Creek sediment samples adjacent to a plasticulture field contained significantly higher copper concentrations than sediments taken from nonplasticulture watersheds.     

Groundwater circulation well operation using wind turbine–generated energy

An investigation was conducted regarding the potential economic benefits associated with using a wind turbine to power a groundwater circulation well (GCW) at the former Nebraska Ordnance Plant Superfund site. The first phase of the investigation used a 10‐kilowatt‐rated grid inter‐tie wind turbine to partially offset the purchase of electricity from the utility company. The second phase consisted of the conversion of the grid inter‐tie system to an off‐grid system that stored energy using batteries. During the second phase, the GCW system was operated using either wind turbine power or utility power, and the other system components were operated using utility power. The study showed that a significant amount of power purchased from the utility company was used for nonessential purposes (other than operating the GCW pump and essential treatment components). One nonessential power consumer was the continuous heating of the equipment shelter for operator comfort during their 10‐minute visit every few days. Wind‐turbine reduction in utility power consumption was evaluated, and the operating time of a hypothetical system powered solely by the wind turbine was compared to the actual GCW operating time. This study indicates that retrofitting this GCW system did not economically offset power costs from a cheap, readily available grid system. Perhaps at a remote location with a more energy‐efficient design and operation and the inclusion of green power benefits (in some monetary amount), the wind turbine results will be more favorable. The study of a renewable energy application at the site highlighted opportunities for significant electrical energy savings regardless of the source of the electricity. © 2008 Wiley Periodicals, Inc.     

Wrestling with the complexity of evaluation for organizations at the boundary of science,policy, and practice

Boundary organizations are situated between science, policy, and practice and have a goal of supporting communication and collaboration among these sectors. They have been promoted as a way to improve the effectiveness of conservation efforts by building stronger relationships between scientists, policy makers, industry, and practitioners (Cook et al. 2013). Although their promise has been discussed in theory, the work of and expectations for boundary organizations are less defined in practice. Biodiversity conservation is characterized by complexity, uncertainty, dissent, and tight budgets, so boundary organizations face the challenging task of demonstrating their value to diverse stakeholders. We examined the challenges boundary organizations face when seeking to evaluate their work and thus aimed to encourage more productive conversations about evaluation of boundary organizations and their projects. Although no off‐the‐shelf solution is available for a given boundary organization, we identified 4 principles that will support effective evaluation for boundary organizations: engage diverse stakeholders, support learning and reflection, assess contribution to change, and align evaluation with assumption and values.     

Hepatitis B triple series vaccine and developmental disability in US children aged 1–9 years

This study investigated the association between vaccination with the Hepatitis B triple series vaccine prior to 2000 and developmental disability in children aged 1–9 years (n = 1824), proxied by parental report that their child receives early intervention or special education services (EIS). National Health and Nutrition Examination Survey 1999–2000 data were analyzed and adjusted for survey design by Taylor Linearization using SAS version 9.1 software, with SAS callable SUDAAN version 9.0.1. The odds of receiving EIS were approximately nine times as great for vaccinated boys (n = 46) as for unvaccinated boys (n = 7), after adjustment for confounders. This study found statistically significant evidence to suggest that boys in United States who were vaccinated with the triple series Hepatitis B vaccine, during the time period in which vaccines were manufactured with thimerosal, were more susceptible to developmental disability than were unvaccinated boys.     

Measuring values for environmental resources under uncertainty

The relationship between conventional Hicksian measures of the benefits from changes in environmental amenities under certainty, and corresponding measures of valuation when the conditions of access to an uncertain environmental resource are changed, is considered. The analysis utilizes a contingent commodity framework with the assumption of state-dependent preferences. The findings suggest that the valuation of these changes will depend upon the availability of fair markets for diversifying risk. Moreover, conventional measures of compensating or equivalent surplus will not necessarily bound the individual's valuation of a change in access to an uncertain environmental resource.     

Mixed signals: market incentives, recycling, and the price spike of 1995

Environmental economics assumes that reliance on price signals, adjusted for externalities, normally leads to efficient solutions to environmental problems. We explore a limiting case, when market volatility created ‘mixed signals’: prices of waste paper and other recycled materials were suddenly extremely high in 1994–1995, then plummeted back to traditional low levels in 1996. These rapid reversals resulted in substantial economic and political costs. A review of academic and business literature suggests six possible explanations for abrupt price spikes. An econometric analysis of the prices of wood pulp and waste paper shows that factor which explained price changes in 1983–1993 contribute very little to understanding the subsequent price spike. From the econometric analysis and from other sources, we conclude that speculation must have played a major role in the price spike, perhaps in combination with modest effects from changes in government policy and in export demand. If speculatively driven price spikes can disrupt an environmentally important industry such as recycling, what is the appropriate role for public policy? When price volatility is sufficiently disruptive, then measures to control or stabilize prices, rather than interfering with the market, might help to make it more efficient.