Using size-based indicators to evaluate the ecosystem effects of fishing   总被引：12，自引：9，他引：12  

Shin  Yunne-Jai; Rochet  Marie-Joelle; Jennings  Simon; Field  John G.; Gislason  Henrik 《ICES Journal of Marine Science》2005,62(3):384-396

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Intraspecific variation in the life history tactics of Atlantic herring (Clupea harengus L.) stocks   总被引：1，自引：0，他引：1  

Jennings  S.; Beverton  R. J. H. 《ICES Journal of Marine Science》1991,48(1):117-125

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Diversity and community structure of epibenthic invertebrates and fish in the North Sea   总被引：5，自引：3，他引：5  

Callaway  R.; Alsvag  J.; de Boois  I.; Cotter  J.; Ford  A.; Hinz  H.; Jennings  S.; Kroncke  I.; Lancaster  J.; Piet  G.; Prince  P.; Ehrich  S. 《ICES Journal of Marine Science》2002,59(6):1199-1214

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A nonlinear model of the solar dynamo     

R. L. Jennings 《Solar physics》1993,143(1):1-17

The role of nonlinearity is explored in a mean-field dynamo model. Magnetic fields are amplified by the combined action of the and-effects, and as the field's intensity increases the Lorentz force becomes important. Torsional oscillations and meridional circulations are driven by the Lorentz force, and the oscillations are consistent with those measured on the surface of the Sun. The torsional oscillations feedback in the induction equation and saturate the magnetic field's growth by quenching differential rotation. This model can also help us understand the processes responsible for the range of periods seen in the activity cycles of other stars like the Sun.  相似文献   

Can marine fisheries and aquaculture meet fish demand from a growing human population in a changing climate?     

Gorka Merino  Manuel Barange  Julia L. Blanchard  James Harle  Robert Holmes  Icarus Allen  Edward H. Allison  Marie Caroline Badjeck  Nicholas K. Dulvy  Jason Holt  Simon Jennings  Christian Mullon  Lynda D. Rodwell 《Global Environmental Change》2012,22(4):795-806

Expansion in the world's human population and economic development will increase future demand for fish products. As global fisheries yield is constrained by ecosystems productivity and management effectiveness, per capita fish consumption can only be maintained or increased if aquaculture makes an increasing contribution to the volume and stability of global fish supplies. Here, we use predictions of changes in global and regional climate (according to IPCC emissions scenario A1B), marine ecosystem and fisheries production estimates from high resolution regional models, human population size estimates from United Nations prospects, fishmeal and oil price estimations, and projections of the technological development in aquaculture feed technology, to investigate the feasibility of sustaining current and increased per capita fish consumption rates in 2050. We conclude that meeting current and larger consumption rates is feasible, despite a growing population and the impacts of climate change on potential fisheries production, but only if fish resources are managed sustainably and the animal feeds industry reduces its reliance on wild fish. Ineffective fisheries management and rising fishmeal prices driven by greater demand could, however, compromise future aquaculture production and the availability of fish products.  相似文献   

Human occupation of the northern Arabian interior during early Marine Isotope Stage 3          下载免费PDF全文

Richard P. Jennings  Ash Parton  Laine Clark‐Balzan  Tom S. White  Huw S. Groucutt  Paul S. Breeze  Adrian G. Parker  Nick A. Drake  Michael D. Petraglia 《第四纪科学杂志》2016,31(8):953-966

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Simplified analysis of unanchored tanks     

R. Peek  P. C. Jennings 《地震工程与结构动力学》1988,16(7):1073-1085

Local uplift of the tank wall is perhaps the most important characteristic of the seismic behaviour of unanchored liquid storage tanks made out of steel. Such uplift is necessary, because unanchored tanks rely primarily on the weight of the liquid resting on an uplifted portion of the base plate to balance the overturning moments that occur during strong shaking. A simplified method of analysis for static lateral loads is developed, based on the assumption that the restraining action of the base plate can be modelled with equivalent, non-linear springs. This assumption, together with a Fourier decomposition of the displacements, simplifies the problem to the extent that it can be solved on a personal computer. The solutions are compared with those from experiments and those from current U.S. design analysis methods.  相似文献   

The effect of salinity-dependent hydraulic conductivity on saltwater intrusion episodes   总被引：2，自引：0，他引：2  

E. Mehnert  A.A. Jennings 《Journal of Hydrology》1985,80(3-4):283-297

The ionic strength of percolating water can greatly alter a soil's hydraulic conductivity. This appears to be the result of dispersion and/or swelling of clay particles, and can alter hydraulic conductivity by several orders of magnitude.

In this paper, the potential effects of salinity-dependent changes in hydraulic conductivity during saltwater intrusions are analyzed. Results are presented to show that this can increase the degree to which brackish water will penetrate a coastal aquifer. This can also increase the width of the dispersed salt front, and can lead to a much greater circulation of saltwater within the intruding saltwater toe. These results may help to explain field observations that have previously been attributed to “scale-dependent” dispersivity and domain heterogeneity.  相似文献   

Monitoring Moisture Migration in the Vadose Zone with Resistivity   总被引：1，自引：0，他引：1  

William F. Kean  Muriel Jennings Waller  H. Richard Layson 《Ground water》1987,25(5):562-571

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Oceanographic Change and Terrestrial Human Impacts in a Post A.D. 1400 Sediment Record from the Southwest Iceland Shelf     

A.E. Jennings  S. Hagen  J. Harðardóttir  R. Stein  A.E.J. Ogilvie  I. Jónsdóttir 《Climatic change》2001,48(1):83-100

Environmental proxies of soil erosion on Iceland, and oceanographic conditions on the adjacent shelf, were measured on a 50 cm box core taken from the southwest Iceland shelf in 1993 during cruise 93030 of the Canadian ship, CSS Hudson. These data, covering the last several centuries, are compared with the documentary record of sea-ice changes around Iceland since A.D. 1600. The site is under the influence of the Irminger Current, which carries warm, saline, Atlantic water northward along the shelf. Because of the relative warmth of this current, sea ice rarely occurs off southwest Iceland, even during the most severe sea-ice intervals of the historical record. In severe sea-ice years, however, the ice drifts clockwise around Iceland from the northeast and east and, in rare cases, reaches the southern coasts (Ogilvie, 1992). The chronology of the core was established by converting the basal radiocarbon date to calendar years and assuming a linear sedimentation rate from the base of the core to the year of collection, 1993. Organic carbon, stable C and O isotope ratios, planktonic foraminiferal assemblages, and sediment magnetic parameters were measured on samples from the core, plotted against calendar years and compared to the Icelandic sea-ice index. The environmental proxies suggest that increased soil erosion, reduced salinity, and, possibly, decreased marine productivity prevailed during the severe sea-ice interval lasting from the last quarter of the eighteenth century to around 1920. Such a situation could develop with climatic cooling, increased storminess, and loss of vegetation cover to stabilise the soil. Although the core site generally lies outside the sea-ice limits, the evidence clearly shows the influence of sea ice and fresh water, and is sensitive to the overall climatic deterioration manifested by the sea-ice record.  相似文献