Balancing end-to-end budgets of the Georges Bank ecosystem

Author Posting. © Elsevier, 2007. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Progress In Oceanography 74 (2007): 423-448, doi:10.1016/j.pocean.2007.05.003.Oceanographic regimes on the continental shelf display a great range in the time scales of physical exchange, biochemical processes and trophic transfers. The close surface-to-seabed physical coupling at intermediate scales of weeks to months means that the open ocean simplification to a purely pelagic food web is inadequate. Top-down trophic depictions, starting from the fish populations, are insufficient to constrain a system involving extensive nutrient recycling at lower trophic levels and subject to physical forcing as well as fishing. These pelagic-benthic interactions are found on all continental shelves but are particularly important on the relatively shallow Georges Bank in the northwest Atlantic. We have generated budgets for the lower food web for three physical regimes (well mixed, transitional and stratified) and for three seasons (spring, summer and fall/winter). The calculations show that vertical mixing and lateral exchange between the three regimes are important for zooplankton production as well as for nutrient input. Benthic suspension feeders are an additional critical pathway for transfers to higher trophic levels. Estimates of production by mesozooplankton, benthic suspension feeders and deposit feeders, derived primarily from data collected during the GLOBEC years of 1995-1999, provide input to an upper food web. Diets of commercial fish populations are used to calculate food requirements in three fish categories, planktivores, benthivores and piscivores, for four decades, 1963-2002, between which there were major changes in the fish communities. Comparisons of inputs from the lower web with fish energetic requirements for plankton and benthos indicate that we obtained reasonable agreement for the last three decades, 1973 to 2002. However, for the first decade, the fish food requirements were significantly less than the inputs. This decade, 1963-1972, corresponds to a period characterized by a strong Labrador Current and lower nitrate levels at the shelf edge, demonstrating how strong bottom-up physical forcing may determine overall fish yields.The research was done under the aegis of the U.S.-GLOBEC Northwest Atlantic Georges Bank Study, a program sponsored jointly by the U.S. National Science Foundation and the U.S. National Oceanic and Atmospheric Administration. We acknowledge NOAA-CICOR award NA17RJ1233 (J.H. Steele), NSF awards OCE0217399 (D.J. Gifford), OCE0217122 (J.J. Bisagni) and OCE0217257 (M.E. Sieracki). W.T. Stockhausen was supported by the NOAA Sponsored Coastal Ocean Research Program

Muscle fibre recruitment can respond to the mechanics of the muscle contraction

This study investigates the motor unit recruitment patterns between and within muscles of the triceps surae during cycling on a stationary ergometer at a range of pedal speeds and resistances. Muscle activity was measured from the soleus (SOL), medial gastrocnemius (MG) and lateral gastrocnemius (LG) using surface electromyography (EMG) and quantified using wavelet and principal component analysis. Muscle fascicle strain rates were quantified using ultrasonography, and the muscle–tendon unit lengths were calculated from the segmental kinematics. The EMG intensities showed that the body uses the SOL relatively more for the higher-force, lower-velocity contractions than the MG and LG. The EMG spectra showed a shift to higher frequencies at faster muscle fascicle strain rates for MG: these shifts were independent of the level of muscle activity, the locomotor load and the muscle fascicle strain. These results indicated that a selective recruitment of the faster motor units occurred within the MG muscle in response to the increasing muscle fascicle strain rates. This preferential recruitment of the faster fibres for the faster tasks indicates that in some circumstances motor unit recruitment during locomotion can match the contractile properties of the muscle fibres to the mechanical demands of the contraction

Mobile Computing from a Developer's Perspective: A 10-Year Review, 1999-2008

This review has examined research in mobile computing from a developer's perspective. The review was underpinned by the assumption that mobile computing has accentuated factors compared to stationary computing that ought to be managed to harness the possibilities of mobile computing. Applying a developer's perspective rendered a certain interest in design-oriented research, i.e. prescriptive research. Articles were categorised in three dimensions; the first dimension was developmental factors accentuated by mobile computing. The second dimension regarded the approach, if it was descriptive or prescriptive. The third dimension regarded the organisational settings, if the user were a member of the mobile workforce or not. The purpose of this study was to identify areas of inquiry in mobile computing from a design-oriented perspective. The findings revealed that research among accentuated factors of mobility is unevenly distributed and that research on the mobile workforce is under-represented. However, design-oriented research has a reasonable representation in the set of publications. The under-representation of research concerning the mobile workforce ought to have relevance for business informatics research. In conjunction with these findings some thoughts on future research areas are presented

Male callers to NHS Direct: The assertive carer, the new dad and the reluctant patient

It has been suggested in the light of mortality and morbidity rates, and men's reluctance to seek medical help and advice, that there is a crisis in men's health. Little is known about men's experiences of using health care services, despite an emergent UK men's health movement. NHS Direct, the new telephone advice line, was designed to be more accessible, convenient and responsive to the public's needs for health care. In-depth interviews with male callers to the service, aged between 29 and 59, reveal that they sought help in their roles as fathers, partners and on their own behalf. Having used it once, they anticipated doing so again. Their learning about health matters, from both the formal structure and the informal agenda of the telephone consultation, suggests the potential of men's use of this service for 'normalizing' help seeking by men, and thereby for longer-term improvements in men's health