Can tree shelterbelts on agricultural land reduce flood risk?   总被引：3，自引：0，他引：3  

Z.L. Carroll  S.B. Bird  B.A. Emmett  B. Reynolds  F.L. Sinclair 《Soil Use and Management》2004,20(3):357-359

Abstract. Agricultural practices in the UK have come under increased scrutiny since the heavy and widespread flooding of 2000 and 2001. Although the impact of land use on runoff and flood risk is of growing concern, there are few quantitative data available. A preliminary study was undertaken in the Nant Pontbren catchment, mid-Wales. Experimental tree shelterbelts were established in selected pastures of land used for sheep grazing. Water infiltration rates were up to 60 times higher in areas planted with young trees than in adjacent grazed pastures. This demonstrates that farm trees could represent a key landscape feature, reducing run-off even when only present as a small proportion of the land cover. This is likely to be just one of the environmental and economic benefits of planting trees to re-create a more diverse agricultural landscape.  相似文献   

The isotopic composition of soil organic carbon on a north–south transect in western Canada     

M. Bird    H. Santrùcková    J. Lloyd  & E. Lawson 《European Journal of Soil Science》2002,53(3):393-403

The minor isotopes of carbon (¹³C and ¹⁴C) are widely used as tracers in studies of the global carbon cycle. We present carbon‐isotope data for the 0–5 cm layer of soil on a transect from 49.6°N to 68°N, from mature forest and tundra ecosystems in the boreal‐arctic zone of interior western Canada. Soil organic carbon in the < 2000 μm fraction of the soil decreases from 3.14 kg m^?2 in the south to 1.31 kg m^?2 in the north. The ¹⁴C activity of the organic carbon decreases as latitude increases from 118.9 to 100.7 per cent modern carbon (pMC). In addition, the ¹⁴C activities of organic carbon in the particle‐size fractions of each sample decrease as particle size decreases. These results suggest that organic carbon in the 0–5 cm layer of these soils transfers from standing biomass into the coarsest size fractions of the soil and is then degraded over time, with the residue progressively transferred into the more resistant finer particle sizes. We calculate residence times for the coarsest size fractions of 21 years in the south to 71 years in the north. Residence times for the fine size fractions (< 63 μm) are considerably longer, ranging from 90 years in the south to 960 years in the north. The δ¹³C of the organic carbon decreases from ?26.8 ± 0.3‰ in soil under forest in the south to ?26.2 ± 0.1‰ for tundra sites in the north. At all sites there is an increase in δ¹³C with decreasing particle size of 0.7–1.6‰. These changes in δ¹³C are due to the presence of ‘old’ carbon in equilibrium with an atmosphere richer in ¹³C, and to the effects of microbial degradation.  相似文献   

Computerised irrigation scheduling using spreadsheet models     

H. Goldsmith  J. D. Bird  S. E. Howarth 《Irrigation and Drainage Systems》1988,2(2):211-227

Microcomputers are increasingly being used to help in the management of smallholder irrigation schemes in Third World countries. In many cases, commercially available spreadsheet packages offer advantages over established scientific programming languages. The paper starts with a review of computer models which have been developed for irrigation scheduling. Two criteria are identified which must be considered when developing computer models for this purpose: realistic data requirements and programs which are easy to understand. Spreadsheet packages provide a good introduction to computing and macro programming techniques can be used to customise spreadsheet models to create refined yet simple management tools. Two practical examples are presented from current research projects:

-a small scale scheme in Zimbabwe, where a spreadsheet model is used to produce irrigation schedules for smallholder farmers;

-a 20,000 ha project in Thailand, where a spreadsheet model makes use of feedback to improve main system scheduling.

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Physics. Electron spin polarization in nanoscale constrictions     

Bird JP  Ochiai Y 《Science (New York, N.Y.)》2004,303(5664):1621-1622

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Periodontal disease in free-ranging koalas (Phascolarctos cinereus) from the Mount Lofty Ranges,South Australia,and its association with koala retrovirus infection     

RG Butcher  LM Pettett  J Fabijan  E Ebrahimie  M Mohammadi-Dehcheshmeh  KN Speight  WSJ Boardman  PS Bird  DJ Trott 《Australian veterinary journal》2020,98(5):200-206

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The use of methylene blue to assist with parotid sialadenectomy in dogs     

I. Gordo  J. J. Camarasa  M. Campmany  F. G. Bird  R. Vallefuoco  H. N. Brissot 《The Journal of small animal practice》2020,61(11):689-695

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Single-chain antigen-binding proteins   总被引：82，自引：0，他引：82  

R E Bird  K D Hardman  J W Jacobson  S Johnson  B M Kaufman  S M Lee  T Lee  S H Pope  G S Riordan  M Whitlow 《Science (New York, N.Y.)》1988,242(4877):423-426

Single-chain antigen-binding proteins are novel recombinant polypeptides, composed of an antibody variable light-chain amino acid sequence (VL) tethered to a variable heavy-chain sequence (VH) by a designed peptide that links the carboxyl terminus of the VL sequence to the amino terminus of the VH sequence. These proteins have the same specificities and affinities for their antigens as the monoclonal antibodies whose VL and VH sequences were used to construct the recombinant genes that were expressed in Escherichia coli. Three of these proteins, one derived from the sequence for a monoclonal antibody to growth hormone and two derived from the sequences of two different monoclonal antibodies to fluorescein, were designed, constructed, synthesized, purified, and assayed. These proteins are expected to have significant advantages over monoclonal antibodies in a number of applications.  相似文献   

ON THE VITAMIN Bc CONJUGATE IN YEAST     

Binkley SB  Bird OD  Bloom ES  Brown RA  Calkins DG  Campbell CJ  Emmett AD  Pfiffner JJ 《Science (New York, N.Y.)》1944,100(2585):36-37

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ISOLATION OF AN ANTIANEMIA FACTOR (VITAMIN Bc CONJUGATE) IN CRYSTALLINE FORM FROM YEAST     

Pfiffner JJ  Calkins DG  O'dell BL  Bloom ES  Brown RA  Campbell CJ  Bird OD 《Science (New York, N.Y.)》1945,102(2644):228-230

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The 10 Australian ecosystems most vulnerable to tipping points   总被引：2，自引：0，他引：2  

William F. Laurance  Bernard Dell  Stephen M. Turton  Michael J. Lawes  Lindsay B. Hutley  Hamish McCallum  Patricia Dale  Michael Bird  Giles Hardy  Gavin Prideaux  Ben Gawne  Clive R. McMahon  Richard Yu  Jean-Marc Hero  Lin Schwarzkopf  Andrew Krockenberger  Michael Douglas  Ewen Silvester  Michael Mahony  Karen Vella  Udoy Saikia  Carl-Henrik Wahren  Zhihong Xu  Bradley Smith  Chris Cocklin 《Biological conservation》2011,(5):1472-1480

We identify the 10 major terrestrial and marine ecosystems in Australia most vulnerable to tipping points, in which modest environmental changes can cause disproportionately large changes in ecosystem properties. To accomplish this we independently surveyed the coauthors of this paper to produce a list of candidate ecosystems, and then refined this list during a 2-day workshop. The list includes (1) elevationally restricted mountain ecosystems, (2) tropical savannas, (3) coastal floodplains and wetlands, (4) coral reefs, (5) drier rainforests, (6) wetlands and floodplains in the Murray-Darling Basin, (7) the Mediterranean ecosystems of southwestern Australia, (8) offshore islands, (9) temperate eucalypt forests, and (10) salt marshes and mangroves. Some of these ecosystems are vulnerable to widespread phase-changes that could fundamentally alter ecosystem properties such as habitat structure, species composition, fire regimes, or carbon storage. Others appear susceptible to major changes across only part of their geographic range, whereas yet others are susceptible to a large-scale decline of key biotic components, such as small mammals or stream-dwelling amphibians. For each ecosystem we consider the intrinsic features and external drivers that render it susceptible to tipping points, and identify subtypes of the ecosystem that we deem to be especially vulnerable.  相似文献