Comparison of Three Commercial Automatic Boom Height Systems for Agricultural Sprayers

Automatic boom height systems reduce the variability of agricultural sprayer boom height. Consistent boom height is important for three key reasons: to reduce uneven spray dispersion if the boom is too low, to reduce spray droplet drift if the boom is too high, and to reduce damage to the boom or crop if the boom is too low. No data is available comparing commercial boom height systems. Three leading North American automatic boom height systems were compared: John Deere BoomTrac Pro (System A), Raven AutoBoom® XRT (System B), and Norac UC5TM Passive Roll (System C) on a John Deere R4045 (Systems A and B) and RoGator 1100C (Systems B and C). Each system was evaluated with three test runs for at least three speeds over each of a mild, medium, and rough terrain course. Boom heights at the left and right outside sensors were measured with the AutoBoom XRT sensors. The accuracy of the automatic boom height systems was quantified with root mean squared deviation (RMSD), the Herbst-modified Hockley Index, and the fraction of points within 10 and 25 cm of target (f10 and f\u3c25). With four exceptions out of 216 comparisons, System B significantly outperformed System A on the R4045 and System C on the RoGator for each metric, at each sensor location, at each speed, on each terrain. At 26 km/h on medium terrain, the RMSD for Systems A and C was 174% and 107% larger than System B, respectively. At 26 km/h on medium terrain, the fraction of points within 25 cm (f\u3c25) was 56% and 21% higher for System B than Systems A and C, respectively. These results indicate System B kept the boom significantly closer to target with significantly less height variability

Health and safety of the older worker

This is the author's pre-copyedited accepted manuscript. The final published article is available from the link below. Copyright @ 2012 The Authors.Background - In the UK, increasing numbers of paid employees are over 60 years with further increases expected as the state pension age rises. Some concern surrounds possible increased work-related illness and accidents for people working beyond the age of 60. Aims - To identify the available evidence for health and safety risks of workers over age 60 years with respect to factors associated with injuries and accidents. Methods - Databases searched included PUBMED, OSHUpdate, National Institute for Occupational Safety and Health (NIOSHTIC-2), SafetyLit, the UK The Health and Safety Executive (HSELINE) and the Canadian Centre for Occupational Health and Safety until December 2009. Inclusion criteria were workers aged over 60 years. Findings were grouped into occupational accidents and injuries and individual and workplace factors that may have influenced risk of injury to the over-60s. Results - Very little direct evidence was found concerning safety practices and health risks of workers over age 60. Some safety risks were associated with specific physical declines such as age-related hearing loss. Overall, these workers had fewer accidents and injuries but these were more likely to be serious or fatal when they occurred. There was no strong evidence that work patterns, including shift work or overtime, affected safety. Protective, compensatory strategies or experience may maintain safe working practices. Conclusions - Implications for health and safety risks cannot be assessed without longitudinal research on workforces with substantial numbers of workers over age 60 in order to address the healthy worker effect.Institution of Occupational Health and Safet

Comparative analysis of Calanus finmarchicus demography at locations around the Northeast Atlantic

Standardized time-series sampling was carried out throughout 1997 at seven locations around the Northeast Atlantic to investigate regional variations in the seasonal demography of Calanus finmarchicus. Sites ranged from an inshore location in the North Sea, where C. finmarchicus formed only a small component of the zooplankton (2000 mgC m-2 during spring and summer). The internal consistency of the demographic time-series from each site was investigated by three partial models of life-cycle processes. In general, the demography of late copepodites could be accounted for by a relatively simple forecast model of stage development and diapause. However, there was a large discrepancy between nowcast estimates of egg production based on female abundance, temperature, and chlorophyll, and hindcast simulations of the egg production required to account for the observed abundance of early copepodite stages. The results point to a gap in our understanding of seasonal variations in rates of egg production and/or survival of nauplii. Overall, the population sampled at Weathership M appeared to be reasonably self-contained, but all other sites were reliant on invasion of overwintered stock in spring. At least two generations were observed at all but one site, but the extent to which these were generated by discrete bursts of egg production varied between sites and seemed to be partly dependent on the proximity to an overwintering location

Biogeography of key mesozooplankton species in the North Atlantic and egg production of Calanus finmarchicus

Here we present a new, pan-North-Atlantic compilation of data on key mesozooplankton species, including the most important copepod, Calanus finmarchicus. Distributional data of eight representative zooplankton taxa, from recent (2000–2009) Continuous Plankton Recorder data, are presented, along with basin-scale data of the phytoplankton colour index. Then we present a compilation of data on C. finmarchicus, including observations of abundance, demography, egg production and female size, with accompanying data on temperature and chlorophyll. This is a contribution by Canadian, European and US scientists and their institutions: http://doi.pangaea.de/10.1594/PANGAEA.820732, http://doi.pangaea.de/10.1594/PANGAEA.824423, http://doi.pangaea.de/10.1594/PANGAEA.828393 (please also see Melle et al., 2013; Castellani and Licandro, 2013; Jónasdóttir et al., 2014)

Biogeography of key mesozooplankton species in the North Atlantic and egg production of Calanus finmarchicus

-Here we present a new, pan-North-Atlantic compilation of data on key mesozooplankton species, including the most important copepod, Calanus finmarchicus. Distributional data of eight representative zooplankton taxa, from recent (2000–2009) Continuous Plankton Recorder data, are presented, along with basin-scale data of the phytoplankton colour index. Then we present a compilation of data on C. finmarchicus, including observations of abundance, demography, egg production and female size, with accompanying data on temperature and chlorophyll

Gender and sustainable livelihoods: linking gendered experiences of environment, community and self

In this essay I explore the economic, social, environmental and cultural changes taking place in Bolsena, Italy, where agricultural livelihoods have rapidly diminished in the last two decades. I examine how gender dynamics have shifted with the changing values and livelihoods of Bolsena through three women’s narratives detailing their gendered experiences of environment, community and self. I reflect on these changes with Sabrina, who is engaged in a feminist community-based organization; Anna, who is running an alternative wine bar; and Isabella, a jeweler, who is engaged in ecofeminist practices. My analysis is based on concepts developed by feminist political ecology: specifically, the theory of rooted networks from Dianne Rocheleau, Donna Haraway’s concept of naturecultures (and the work of J. K. Gibson-Graham on new economic imaginaries emerging from the politics of place. I aim to think with, reflect upon and provoke from the ‘‘otherwise’’, taking into account the lived relations entwining nature and gender. My article looks at the interconnections of gender, environment and livelihoods, attentive to the daily needs, embodied interactions and labours of these three women as part of a reappropriation, reconstruction and reinvention of Bolsena’s lifeworld. By listening to the stories of their everyday lives and struggles, I show the dynamic potential of the politics of place and the efforts to build diverse economies and more ethical economic and ecological relationships based on gender-aware subjectivities and values

Prey detection and prey capture in copepod nauplii

Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds numbers due to the thick viscous boundary layer surrounding the attacking nauplius. We use high-speed video to describe the detection and capture of phytoplankton prey by the nauplii of two ambush feeding species (Acartia tonsa and Oithona davisae) and by the nauplii of one feeding-current feeding species (Temora longicornis). We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws in the prey

The effects of shoulder load and pinch force on electromyographic activity and blood flow in the forearm during a pinch task

The object of the current study was to determine whether static contraction of proximal musculature has an effect on the blood flow more distally in the upper extremity. Static contractions of muscles in the neck shoulder region at three levels (relaxed, shoulders elevated and shoulders elevated loaded with 4.95 kg each) were combined with intermittent pinch forces at 0, 10 and 25% of the maximum voluntary contraction (MVC). Blood flow to the forearm was measured with Doppler ultrasound. Myoelectric activity of the forearm and neck-shoulder muscles was recorded to check for the workload levels. Across all levels of shoulder load, blood flow increased significantly with increasing pinch force (21% at 10% MVC and by 44% at 25% MVC). Blood flow was significantly affected by shoulder load, with the lowest blood flow at the highest shoulder load. Interactions of pinch force and shoulder load were not significant. The myoelectric activity of forearm muscles increased with increasing pinch force. The activation of the trapezius muscle decreased with increasing pinch force and increased with increasing shoulder load. The precise mechanisms accounting for the influence of shoulder load remains unclear. The results of this study indicate that shoulder load might influence blood flow to the forearm