Climate change will affect the ability of forest management to reduce gaps between current and presettlement forest composition in southeastern Canada     

Boulanger  Yan  Arseneault  Dominique  Boucher  Yan  Gauthier  Sylvie  Cyr  Dominic  Taylor  Anthony R.  Price  David T.  Dupuis  Sébastien 《Landscape Ecology》2019,34(1):159-174

Landscape Ecology - Forest landscapes at the boreal–temperate ecotone have been extensively altered. Reducing the gap between current and presettlement forest conditions through...  相似文献   

Embodied Resources in Fish and Shrimp Feeds          下载免费PDF全文

Sirirat Chatvijitkul  Claude E. Boyd  D. Allen Davis  Aaron A. McNevin 《Journal of the World Aquaculture Society》2017,48(1):7-19

Global averages were obtained for amounts of energy, land, water, wildfish, nitrogen, and phosphorus embodied in aquaculture feed ingredients. These data allowed amounts of these embodied resources to be calculated for typical feed formulations for channel catfish, Ictalurus punctatus; hybrid catfish, I. punctatus♀ × I. furcatus♂; Vietnamese catfish, Pangasius spp.; Atlantic salmon, Salmo salar; rainbow trout, Oncorhynchus mykiss; tilapia, Oreochromis spp.; whiteleg shrimp, Litopenaeus vannamei; and black tiger shrimp, Penaeus monodon. Embodied resource use per m.t. of feed varied among species: energy, 4.90–12.48 GJ/m.t.; land, 0.082–0.312 ha/m.t.; water, 502–1227 m³/m.t.; wildfish, 0–2880 kg/m.t.; nitrogen, 3.08–8.63 kg/m.t.; phosphorus, 1.16–5.62 kg/m.t. These calculations did not account for variations in site‐specific factors related to embodied resources and feed composition and use. But they suggest that reducing feed conversion ratio (FCR) by 0.1 unit for the seven species (species groups) could potentially reduce feed use by around 1.1 million tonne (Mt) while conserving 9.8 million GJ of energy, 270,000 ha of agricultural land, 1.4 billion m³ of freshwater, and 1.24 Mt of wildfish. Reduction of the FCR is a powerful means of lessening farm‐level production costs and negative impacts of feed production and use.  相似文献   

Effects of brodifacoum and diphacinone exposure on four species of reptiles: tissue residue levels and survivorship     

Richard E Mauldin  Gary W Witmer  Susan A Shriner  Rachael S Moulton  Katherine E Horak 《Pest management science》2020,76(5):1958-1966

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Silage and total mixed ration hygienic quality on commercial farms: implications for animal production          下载免费PDF全文

T. Cogan  R. Hawkey  E. Higgie  M. R. F. Lee  E. Mee  D. Parfitt  J. Raj  S. Roderick  N. Walker  P. Ward  J. M. Wilkinson 《Grass and Forage Science》2017,72(4):601-613

Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling.  相似文献   

Soil protection for a sustainable future: options for a soil monitoring network for Ireland          下载免费PDF全文

L. O'Sullivan  F. Bampa  K. Knights  R. E. Creamer 《Soil Use and Management》2017,33(2):346-363

The increased recognition of the importance of soil is reflected in the UN Post‐2015 Development Agenda with sustainable development goals that directly and indirectly relate to soil quality and protection. Despite a lack of legally binding legislation for soil protection, the European Commission remains committed to the objective of soil protection. However, the achievement of a legally binding framework for soil protection relies on the implementation of a soil monitoring network (SMN) that can detect changes to soil quality over time. As beneficiaries do not pay for the provision of soil information, the options for soil monitoring are limited. The use of existing data sets should be considered first. Using Ireland as an example, this research explored the opportunities for a SMN for Ireland considering three existing national data sets. The options for a SMN are considered in terms of their spatial and stratified distribution, the parameters to be measured and an economic analysis of the options proposed. This research finds that for Ireland, either a 10 or a 16 km² grid interval stratified by land use and drainage class offers the best potential in relation to the spatial distribution of existing data sets to reflect local data at a national level. With existing data, the stratified SIS data using the 16 km² grid offers the best value for money, with baseline costs for analysis, excluding field costs, of between €706 481 and €2.8 million. Acknowledging the impossibility of measuring all parameters with ideal frequency, this study proposes a two‐tier system for optimized monitoring frequency. Parameters must anticipate future policy requirements. Finally, the implementation of a SMN must be accompanied by standardized methods, defined thresholds and action mandates to maintain soil quality within allowable limits.  相似文献   

Novel mechanism of thrips suppression by Cry51Aa2.834_16 Bt toxin expressed in cotton     

Anders S Huseth  Damon A D&#x;Ambrosio  Benjamin T Yorke  Graham P Head  George G Kennedy 《Pest management science》2020,76(4):1492-1499

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Nano-calcium carbonate reinforced polypropylene and propylene-ethylene copolymer nanocomposites: Tensile vs. impact behavior     

Mangala Joshi  Satyajit Brahma  Anasuya Roy  S. Wazed Ali 《Fibers and Polymers》2017,18(11):2161-2169

Improvement of both the tensile and impact strength of the same polymeric material has always been a great challenge for the plastic industry. The study focuses on the effect of incorporation of calcium carbonate nanoparticles (0.3 wt% to 15 wt%) into three polypropylene (PP) based matrices viz. PP homopolymer, propylene-ethylene (PP-PE) copolymer and the blend of PP:PP-PE (30:70) to improve their impact behavior without hampering the tensile strength much. A loss in both the tensile and impact properties was observed in PP based nanocomposite. However, PP-PE based nanocomposites showed a significant improvement in impact strength (47 %) at 10 wt% loading with a loss of tensile strength by 22 %. To minimize this loss a blend of PP:PP-PE (30:70) was explored as a matrix. At 10 wt% loading, this matrix showed an improvement of 30 % in impact strength whereas the tensile loss was minimized to 10 %. Further, silane coupling agent which promoted good interfacial adhesion was used for best compositions. The variation of crystalline morphology of the nanocomposites with various formulations was analyzed using differential scanning calorimetry and X-ray diffraction.  相似文献   

Immunodeficiency associated with lymphosarcoma in a horse.     

M O Furr  M V Crisman  J Robertson  O Barta  W S Swecker 《Journal of the American Veterinary Medical Association》1992,201(2):307-309

Immune system dysfunction and immunoglobulin deficiency was diagnosed in a 2-year-old horse with disseminated lymphosarcoma. Prolonged (35 days) parenteral nutrition was delivered to support the horse during a period in which immune function studies could be performed. Correction of nutritional compromise by use of parenteral nutrition did not correct the immunoglobulin deficiency, and results of lymphocyte phenotype testing did not indicate abnormal proportions of leukocytes. Lymphoblast transformation studies were suggestive of a circulating immunosuppressive factor in the horse's serum. Normal cell function was detected when the cells were stimulated in precolostral equine serum.  相似文献   

Factors affecting skim milk progesterone assay results.     

R F Nachreiner  S J Oschmann  L E Edqvist  J I Richards 《American journal of veterinary research》1992,53(7):1085-1089

Five studies were performed to determine factors affecting progesterone concentration in skim milk. Results of the first study indicated that progesterone concentration was higher in skim milk of samples kept 16 hours in an ice bath (0 C) than of those left at room temperature (21 C). In the second study, this temperature effect was found to be reversible, with skim milk progesterone concentration increasing when whole milk samples were cooled prior to centrifugation. In the third study, [3H]-labeled progesterone was used to determine the relationship between fat content of foremilk (the first milk obtained from the teats), midmilk (milk obtained midway through milking), and strippings (milk obtained immediately after milking machines have been removed) samples and temperature (4 C and 21 C) on the percentage of progesterone in the skim milk fraction. The relationship between percentage of butterfat and percentage of progesterone in skim milk was linear when the log of these variables was used for calculations. In the fourth study, assayable progesterone in the skim milk fraction of foremilk, midmilk, and strippings was affected by temperature. In the fifth study, a multiple-regression procedure was used to determine the amount of variation in percentage of radioactive progesterone in the skim milk fraction. Independent variables (whole milk butterfat and temperature of incubation [1, 3, 13, 22, 37, and 50 C]) and the natural log of each variable, were entered into a stepwise multiple-regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Evaluation of rhinoscopy and rhinoscopy-assisted mucosal biopsy in diagnosis of nasal disease in dogs: 119 cases (1985-1989).     

S E Lent  E C Hawkins 《Journal of the American Veterinary Medical Association》1992,201(9):1425-1429

The case records of 149 dogs examined from 1985 to 1989 with clinical signs of nasal disease were reviewed. Gross rhinoscopy was performed in 119 dogs, and rhinoscopy-assisted pinch biopsy was performed in 109. Rhinoscopy was performed by use of a 2.7-mm rigid fiberoptic endoscope. Mucosal biopsy specimens were obtained with rhinoscopic guidance by use of a 2 x 3-mm biopsy forcep. Gross, cytologic, and histologic findings are summarized. Ninety-four of 119 cases could be evaluated on the basis of diagnostic and follow-up criteria established by the authors. The diagnostic success rate of gross rhinoscopy with rhinoscopy-assisted biopsy was 83% (78 of 94 evaluated cases). Protracted hemorrhage was a complication in 2 of 109 cases in which rhinoscopy-assisted biopsy was performed. It was concluded that rhinoscopy with rhinoscopy-assisted biopsy contributes important diagnostic information in dogs with nasal disease without the relative invasiveness, expense, and risk of surgery.  相似文献