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571.
572.
Mike Mentis 《中国林学(英文版)》2015,(1):31-44
This article considers threats to a project slipping on budget,schedule and fit-for-purpose.Threat is used here as the collective for risks(quantifiable bad things that can happen)and uncertainties(poorly or not quantifiable bad possible events).Based on experience with projects in developing countries this review considers that(a)project slippage is due to uncertainties rather than risks,(b)while eventuation of some bad things is beyond control,managed execution and oversight are stil the primary means to keeping within budget,on time and fit-for-purpose,(c)improving project delivery is less about bigger and more complex and more about coordinated focus,effectiveness and developing thought-out heuristics,and(d)projects take longer and cost more partly because threat identification is inaccurate,the scope of identified threats is too narrow,and the threat assessment product is not integrated into overall project decision-making and execution.Almost by definition,what is poorly known is likely to cause problems.Yet it is not just the unquantifiability and intangibility of uncertainties causing project slippage,but that they are insufficiently taken into account in project planning and execution that cause budget and time overruns.Improving project performance requires purpose-driven and managed deployment of scarce seasoned professionals.This can be aided with independent oversight by deeply experienced panelists who contribute technical insights and can potentially show that diligence is seen to be done. 相似文献
573.
An experiment was conducted to test the hypothesis that the requirement for Ca expressed as a ratio between standardized total tract digestible (STTD) Ca and STTD P obtained in short-term experiments may be applied to pigs fed diets without or with microbial phytase from 11 to 130 kg. In a 5-phase program, 160 pigs (body weight: 11.2 ± 1.8 kg) were randomly allotted to 32 pens and 4 corn–soybean meal-based diets in a 2 × 2 factorial design with 2 diet formulation principles (total Ca or STTD Ca), and 2 phytase inclusion levels (0 or 500 units/kg of feed) assuming phytase released 0.11% STTD P and 0.16% total Ca. The STTD Ca:STTD P ratios were 1.40:1, 1.35:1, 1.25:1, 1.18:1, and 1.10:1 for phases 1 to 5, and STTD P was at the requirement. Weights of pigs and feed left in feeders were recorded at the end of each phase. At the conclusion of phase 1 (day 24), 1 pig per pen was euthanized and a blood sample and the right femur were collected. At the end of phases 2 to 5, a blood sample was collected from the same pig in each pen. At the conclusion of the experiment (day 126), the right femur of 1 pig per pen was collected and carcass characteristics from this pig were measured. No interactions were observed between diet formulation principle and phytase inclusion for growth performance in any phase and no differences among treatments were observed for overall growth performance. Plasma Ca and P and bone ash at the end of phase 1 were also not influenced by dietary treatments. However, on day 126, pigs fed nonphytase diets formulated based on total Ca had greater bone ash than pigs fed STTD Ca-based diets, but if phytase was used, no differences were observed between the 2 formulation principles (interaction P < 0.05). At the end of phases 2 and 3, pigs fed diets without phytase had greater (P < 0.05) plasma P than pigs fed diets with phytase, but no differences were observed at the end of phases 4 and 5. A negative quadratic effect (P < 0.05) of phase (2 to 5) on the concentration of plasma Ca was observed, whereas plasma P increased (quadratic; P < 0.05) from phases 2 to 5. However, there was no interaction or effect of diet formulation principle or phytase inclusion on any carcass characteristics measured. In conclusion, STTD Ca to STTD P ratios can be used in diet formulation for growing-finishing pigs without affecting growth performance or carcass characteristics and phytase inclusion ameliorates bone resorption caused by low dietary Ca and P. 相似文献
574.
Tracer kinetics and single cell sampling both suggest that S is compartmented differently in vacuoles of epidermal and mesophyll cells. Cytoplasmic S turns over rapidly, but vacuolar turnover in both cell types is too slow to support plant growth, thus accounting in part for the apparent low mobility of S in mature leaves. 相似文献
575.
Sigua Gilbert C. Holtkamp Mike L. Linton John M. Coleman Samuel W. 《Journal of Soils and Sediments》2003,3(2):93-99
Background The continued need to dredge lakes, rivers, and canals in Florida, both for maintenance and environmental improvement, will
produce millions of cubic meters of dredged materials. Productive disposal options of lake-dredged materials (LDM) may provide
substantial and intangible benefits that will enhance the environment, community, and society.
Objective The objective of this study was to assess lake-dredged materials from Lake Panasoffkee as soil amendment for early establishment
of bahiagrass (BG,Paspalum notatum Flügge) in subtropical beef cattle pasture at Sumter County, Florida. Results and Discussion. This study encompassed two
phases: Phase 1 comprised of five small observation plots (0.3 x 0.3 m); Phase 2 consisted of five larger test plots (30.5
x 30.5 m). Each of the plots in Phase 1 and Phase 2 had a different ratio LDM to natural soil (NS): Plot 1 (0% LDM + 100%
NS); Plot 2 (25% LDM + 75% NS); Plot 3 (50% LDM + 50% NS); Plot 4 (75% LDM + 25% NS); and Plot 5 (100% LDM + 0% NS). Each
plot was seeded with BG and early growth and yield establishment were monitored for 16 weeks.
Conclusion Results disclosed significantly taller (p ≤ 0.001) plants and higher biomass production (p ≤ 0.001) of BG from plots amended
with 75% LDM than those of BG planted on plots with 0% LDM. Results suggest that LDM can serve as source of lime and fertilizer
to establish BG beef pasture fields. Sediments with high CaCO3 improved the physical and chemical conditions of subtropical beef pastures. Lake-dredged materials could be removed from
the spoil containment areas, trucked to other locations, and incorporated into existing fields for agricultural uses. There
is still much to be learned, but it is certain that Lake Panasoffkee sediments should be regarded as a resource, with no observed
harmful ecological effects.
Recommendation and Outlook The agricultural or livestock industry could utilize these LDM to produce forages. LDM should be regarded as a beneficial
resource, as a part of the ecological system. This study has been continued for several years to explore and assess the long
term efficacy of LDM on productivity and quality of BG beyond its early establishment stage.
Joint contribution of the USDA-ARS and the Florida Agricultural Experiment Station, Journal Series No, R-09253. 相似文献
576.
577.
Warren K. Coleman Gary Hawkins Jeff McInerney Marcus Goddard 《American Journal of Potato Research》1992,69(7):437-445
Tuber dormancy can be released immediately in many commercially important potato cultivars by brief treatment (1-2 days) with bromoethane (BE) vapor at room temperature. The development of a large scale technology for BE application and safe removal through a capturing technique is necessary for successful application of this dormancy release method. Ideally, BE treatment of seed tubers would occur in a closed environment that would capture BE vapor in an unaltered form and allow controlled release for treatment of subsequent tuber lots. Results of screening studies for adsorbents indicate that the medium capacity activated carbon adsorbent, YAO has: i) a high capacity for BE; ii) a low capacity for water; and, iii) adsorbs and de-adsorbs BE quickly and easily. A plausible design of a large scale, dormancy release facility is presented. The proposed facility should meet present goals of the seed potato industry in an environmentally responsible manner. 相似文献
578.
Felipe Balocchi Mike J. Wingfield Rodrigo Ahumada Irene Barnes 《Plant pathology》2021,70(5):1243-1259
Araucaria araucana, (commonly referred to as araucaria, pewen, or monkey puzzle tree) is an ancient conifer endemic to the Chilean and Argentinian mountain ranges where it has a sacred relevance to indigenous communities. During 2015, a serious disease was noticed on trees of all ages in most of the natural distribution of this iconic tree. Four areas were surveyed, and the most important symptoms of the disease were cankers on branches and stems resulting in copious resin exudation. Trees were monitored for a period of two years and isolations were made from the cankers. Field observations showed that the disease typically begins on the leaves or at the leaf bases and progresses downwards to initiate cankers that can girdle branches or stems within a two-year period. Black ascomata, resembling those of Caliciopsis species previously described from A. araucana, were consistently found developing in the cankers from which isolations were made. Phylogenetic analyses of the ITS, nucSSU, and nucLSU gene regions showed that the fungus resides in the Coryneliaceae but is distinct from other genera in that family. The morphological characteristics and phylogenetic position of the fungus show that it represents a new genus and species, described here as Pewenomyces kutranfy gen. nov. et sp. nov. Pathogenicity trials on trees under field conditions confirmed that this newly described fungus is able to cause cankers on A. araucana similar to those found under natural conditions. 相似文献
579.
OBJECTIVE: To determine change over time in sero-prevalence of antibodies against Lawsonia intracellularis among growing-finishing pigs housed in indoor versus outdoor facilities. DESIGN: Serologic survey. ANIMALS: 93 pigs born to seropositive gilts and raised in indoor (n = 49) or outdoor (44) growing-finishing facilities. PROCEDURE: Blood samples were collected from the pigs 2, 6, 10, 14, 18, 22, and 26 weeks after birth and tested for antibodies against L intracellularis with an indirect immunofluorescence assay. RESULTS: None of the pigs were seropositive 2 or 6 weeks after birth.Ten weeks after birth, 74% and 76% of pigs in indoor and outdoor growing-finishing facilities were seropositive, respectively, whereas 14 weeks after birth, the percentage of pigs in indoor growing-finishing facilities that were seropositive was substantially higher than the percentage of pigs in outdoor facilities that were. From 18 weeks after birth to the end of the study, none of the pigs in outdoor growing-finishing facilities were seropositive, whereas low percentages of pigs in indoor facilities were seropositive 18, 22, and 26 weeks after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that seroprevalence of antibodies against L intracellularis decreases faster among growing-finishing pigs housed in outdoor facilities than among growing-finishing pigs housed in indoor facilities. 相似文献
580.
Thomas Miedaner Judith Elfriede Schmid Kerstin Flath Silvia Koch Andreas Jacobi Erhard Ebmeyer Mike Taylor 《European journal of plant pathology / European Foundation for Plant Pathology》2018,151(2):451-461
Wheat is affected by many diseases, in Germany eight fungal diseases are recorded during the cultivar registration process. For a commercially successful cultivar, therefore, at least moderate resistances to important diseases, like yellow rust (YR) and Fusarium head blight (FHB), are necessary. Additionally, in 2013 a regional stem rust (SR) epidemic occurred in Central Germany for the first time for decades. Our objective was to analyze the resistance of 36 commercially grown winter wheat cultivars to YR, FHB, and SR in three individual and one combined inoculation. Appreciable disease severities were achieved for YR and FHB at three to four locations in two years (= seven location × year combinations), for SR at one to two locations in two years (= three location × year combinations). Wheat cultivars showed a significant genotypic variation for all diseases with high heritabilities (0.90–0.95). Interaction between inoculation treatments (individual vs. combined) and wheat genotype was not significant for each of the three diseases. Accordingly, correlations between both inoculation treatments were very high (R2?=?0.95–0.99). Several cultivars showed multi-disease resistance (MDR) to YR, FHB, and SR. In conclusion, resistance ranking among genotypes was not changed when plants were challenged with all three pathogens together compared to factorial inoculations of only one of them. Substituting factorial inoculation trials by multi-pathogen inoculation makes it more efficient to select for MDR in practical breeding programs. 相似文献