Long-term changes in fish populations of acid streams and lochs in galloway South West Scotland     

R. Harriman  B. R. S. Morrison  L. A. Caines  P. Collen  A. W. Watt 《Water, air, and soil pollution》1987,32(1-2):89-112

During 1978–79, and again in 1984, fish populations were surveyed in 22 lochs and 27 streams in Galloway, southwest Scotland. Chemical analyses of these waters and of bulk precipitation were made over the same period. The study area includes moorland catchments and catchments with young or semi-mature coniferous forest. Trout were not caught in nets set in 5 lochs which were known to contain fish in the past. Angling records also indicated a decline in catches and increased average weight of trout in two other lochs. Evidence for the decline in fish populations suggests that this process has occurred over a period of at least 50 yr. In fishless lochs and streams the levels of acidity and Al were in the range known to be toxic to fish. Stream acidity and sulphate concentrations were significantly higher in catchments with semi-mature coniferous forests. The available evidence for long-term acidification of Galloway lochs and streams is discussed and it is concluded that acid depositions are likely to be the major cause of changes in the status of fisheries in this region.  相似文献   

Breast-feeding initiation and exclusive duration at 6 months by social class--results from the Millennium Cohort Study     

Kelly YJ  Watt RG 《Public health nutrition》2005,8(4):417-421

OBJECTIVES: To assess breast-feeding initiation and rates of exclusive breast-feeding for the first 6 months after birth, and to examine social class differences in breast-feeding rates. DESIGN: First sweep of a longitudinal population-based survey, the Millennium Cohort Study. SETTING: Four countries of the UK. SUBJECTS: Subjects were 18 125 singletons born over a 12-month period spanning 2000-01. Data were collected by parental interview on the initiation of breast-feeding and exclusivity at 1, 4 and 6 months after birth. RESULTS: Overall breast-feeding was initiated for 71% of babies, and by 1, 4 and 6 months of age the proportions being exclusively breast-fed were 34%, 3% and 0.3%, respectively. There were clear social class differences and mothers with routine jobs with the least favourable working conditions were more than four times less likely (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.18-0.29) to initiate breast-feeding compared with women in higher managerial and professional occupations. Women in routine jobs were less likely to exclusively breast-feed their infants at 1 month (OR 0.42, 95% CI 0.36-0.50) and 4 months (OR 0.5, 95% CI 0.31-0.77) compared with women in higher managerial and professional occupations. CONCLUSIONS: Clear social class differences in breast-feeding initiation and exclusivity for the first 4 months were apparent in this large UK sample. By 6 months, less than 1% of babies were being exclusively breast-fed. A co-ordinated multi-faceted strategy is required to promote breast-feeding, particularly among lower-income women.  相似文献   

ANNUAL REPORT OF THE EXECUTIVE COMMITTEE FOR THE YEAR ENDED 31st MAY, 1952     

W. E. Watt 《Southern Forests》2013,75(1)

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Arthrodesis of the Equine Proximal Interphalangeal Joint: A Biomechanical Comparison of Two 7-Hole 3.5-mm Broad and Two 5-hole 4.5-mm Narrow Dynamic Compression Plates     

Bruce C. Watt  DVM    Ryland B. Edwards III  DVM  MS  Diplomate ACVS  Mark D. Markel  DVM  PhD  Diplomate ACVS    Ron McCabe  David G. Wilson  DVM  Diplomate ACVS 《Veterinary surgery : VS》2002,31(1):85-93

OBJECTIVE: To compare the biomechanical characteristics and mode of failure of two different dynamic compression plate (DCP) techniques for proximal interphalangeal joint (PIPJ) arthrodesis in horses. STUDY DESIGN: Randomized block-design blocking on horse (1-5), method of fixation (two 7-hole, 3.5-mm broad DCP vs two 5-hole, 4.5-mm narrow DCP), side (left, right), and end (front, hind). Constructs were loaded to failure in 3-point bending in a dorsal-to-palmar (plantar) direction. SAMPLE POPULATION: Ten paired limbs from 5 equine cadavers. METHODS: Two 7-hole, 3.5-mm broad dynamic compression plates (bDCP) were used in 1 limb of a pair, and two 5-hole 4.5-mm narrow dynamic compression plates (nDCP) were used on the contralateral limb. Plates were positioned abaxially across the dorsomedial and dorsolateral aspect of the PIPJ. Arthrodesis constructs were loaded (19 mm/s) in 3-point bending in a dorsal-to-palmar (plantar) direction using a materials-testing machine. Composite stiffness, yield point, and maximal bending moment at failure were obtained from bending moment-angular deformation curves. Data were analyzed using ANOVA, X(2) analysis, and Fisher's exact tests; the power of the test was calculated when differences were not significant. RESULTS: There were no significant differences in composite stiffness (P >.05; power = 0.8 @ delta = 21.9%), yield point (P >.05; power = 0.8 @ delta = 34.4%), or maximal bending moment (P >.05; power = 0.8 @ delta = 17.8%) between the two fixation techniques. For bDCP constructs, 11% (15 of 140) of the 3.5-mm screws were damaged; 7 of the screw heads pulled through plates where the plates bent, 1 screw head broke off, and 7 screws were bent or pulled out of the phalanx. For nDCP constructs, 8% (8 of 100) of the 4.5-mm screws were damaged; 1 screw head pulled through a plate, 1 screw head broke off, and 6 screws were bent or pulled out of the phalanx. CONCLUSIONS: There were no biomechanical or failure differences between bDCP and nDCP fixation of the PIPJ in horses when evaluated in single-cycle 3-point bending to failure. CLINICAL RELEVANCE: There is no biomechanical advantage to the use of two 7-hole, 3.5-mm bDCP in equine proximal interphalangeal arthrodesis compared with two 5-hole, 4.5-mm nDCP. Two 5-hole, 4.5-mm nDCP may be easier to place, whereas two 7-hole, 3.5-mm bDCP may provide more versatility in fracture repair.  相似文献   

Advances in modelling and decision support systems for vegetation management in young forest plantations   总被引：1，自引：0，他引：1  

Richardson  Brian; Watt  Michael S.; Mason  Euan G.; Kriticos  Darren J. 《Forestry》2006,79(1):29-42

The two most common forest vegetation management objectivesare to (1) minimize resource competition, and (2) to developmethods for managing specific weed species. This paper reviewsrelevant models and decision support systems for assisting inachieving these objectives. The aim of reducing resource competitionis to increase crop-tree growth and survival. Several modellingapproaches have been applied to this problem and these generallyestimate crop survival and growth benefits following some formof generalized weed control. Linkages with models of older treecrops are needed for comparing vegetation management strategiesin the context of complete silvicultural regimes. More refinedindividual tree models use competition indices to estimate thequantity of weed vegetation within the growing space aroundeach tree. The indices reflect resource use by the weeds andare sensitive to changes in weed growth over time and to theapplication of specific vegetation management treatments. Hybridand process-based models have the potential to provide moregeneralized models of inter-specific competition, but theirusefulness for forest practitioners has yet to be proven. Someforest vegetation management problems require a more detailedunderstanding of the biology and ecology of a specific species.In this case, different modelling approaches that consider overallweed population dynamics, distribution or spread may be appropriate.  相似文献   

OVULATION,OESTRUS AND COPULATION WITH CONSEQUENT DYSTOCIA DURING PREGNANCY,IN THE MOUSE     

Watt LJ 《Science (New York, N.Y.)》1931,73(1881):75-76

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Acid Toxicity Levels in Nova Scotian Rivers Have Not Declined in Synchrony with the Decline in Sulfate Levels     

Watt  W. D.  Scott  C. D.  Zamora  P. J.  White  W. J. 《Water, air, and soil pollution》2000,118(3-4):203-229

The Atlantic salmon (Salmo salar) resource of eastern Canada is impacted by acid rain in the Southern Upland (Atlantic Coast) area of Nova Scotia. Salmon runs in this area have become extinct in 14 rivers, are severely impacted in 20 rivers, and lightly impacted in 15 rivers. Water chemistry and fish communities in nine Southern Upland salmon rivers were studied from 1982 to 1996 as part of the effort to monitor the effects of the emission controlprograms in Canada and the United States. There hasbeen no statistically significant change in total ioncontent of Southern Upland river water, but there wasa significant decline in sulfate levels that was balanced by an increase in organic anions, and declines in calcium and magnesium that were balanced by increases in sodium and potassium. A geochemical scenario is proposed to account for these chemical changes. River water pH levels showed no overall linear trend, but at borderline toxicity sites the year-to-year variations in pH were correlated withchanges in juvenile salmon population densities. Tenfish species were collected, but none showed anysignificant overall time trend in population density.Fish species diversity was positively correlated with pH.  相似文献   

Larvae of Elaphostrongylus cervi in the deer of Scotland     

A W English  C F Watt  W Corrigall 《The Veterinary record》1985,116(10):254-256

Protostrongylid larvae were recovered from the faeces or lungs of red deer (Cervus elaphus), roe deer (Capreolus capreolus) and reindeer (Rangifer tarandus) in Scotland during 1981. Typical protostrongylid first-stage larvae were also recovered from possible intermediate hosts, the grey field slug (Agriolimax reticulata) and the white-soled slug (Arion fasciatus). All these protostrongylid larvae were microscopically identical to those of the nematode Elaphostrongylus cervi. Despite careful search, adult E cervi were not found, but it is concluded that infection with E cervi is widespread in Scottish deer.  相似文献   

Further observations on the slaughter of poultry     

G B Heath  D J Watt  P R Waite  P A Meakins 《The British veterinary journal》1983,139(4):285-290

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Comparison by experimental infections in cattle of a Dictyocaulus species occurring naturally in red deer and a dictyocaulus of bovine origin     

W Corrigall  A G Coutts  C F Watt  A R Hunter  R Munro 《The Veterinary record》1988,122(13):302-304

Dictyocaulus species larvae were obtained from young red deer which had become infected on pastures considered to be carrying the Dictyocaulus species indigenous to the red deer of Scotland. These larvae were cultured to third stage and transmitted to five bovine calves. Five other bovine calves were infected with third stage Dictyocaulus viviparus larvae of bovine origin. Microscopic appearances of both groups of larvae were indistinguishable and their lengths were similar. Results indicated that the Dictyocaulus species derived from deer induced milder though similar clinical and pathological responses in cattle than did the D viviparus derived from cattle. It was concluded that there are strains of different pathogenicity within the species D viviparus, that the deer derived Dictyocaulus species was a strain of D viviparus, and that the hazards to animal health associated with infection by D viviparus in farming systems where red deer and cattle may graze alternately are likely to be acceptable.  相似文献