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91.
When devising policies for financing private silvicultural operations on public forest land, government agencies should consider carefully the benefits and costs of alternative arrangements and how they arc likely to affect tenure holders' behavior. Three general methods of achieving silvicultural objectives arc discussed — the creation of incentives for private voluntary expenditures, reimbursement by governments of expenditures on approved or required silvicultural operations, and required silvicultural operations at the tenure holder's expense.Private firms will only invest voluntarily in silviculture on public lands if they have adequate security of tenure and hold sufficient equity in the timber values resulting from their activities. If firms' silvicultural costs arc reimbursed, their behavior will depend on the extent of reimbursement and whether they have a financial interest in the outcomes of their reimbursed activities. Generally, reimbursement of expenditures must be supported by minimum performance standards and costly monitoring and enforcement procedures. If silvicultural operations are required at the tenure holder's expense, firms will only undertake silviculture to avoid penalties and have a strong incentive to achieve required standards at minimum cost. More stringent monitoring and enforcement procedures may be necessary than if costs arc reimbursed.The impact of policy alternatives is illustrated by means of a survey of silvicultural expenditures on two forest tenure types in British Columbia. 相似文献
92.
Changelian PS Flanagan ME Ball DJ Kent CR Magnuson KS Martin WH Rizzuti BJ Sawyer PS Perry BD Brissette WH McCurdy SP Kudlacz EM Conklyn MJ Elliott EA Koslov ER Fisher MB Strelevitz TJ Yoon K Whipple DA Sun J Munchhof MJ Doty JL Casavant JM Blumenkopf TA Hines M Brown MF Lillie BM Subramanyam C Shang-Poa C Milici AJ Beckius GE Moyer JD Su C Woodworth TG Gaweco AS Beals CR Littman BH Fisher DA Smith JF Zagouras P Magna HA Saltarelli MJ Johnson KS Nelms LF Des Etages SG Hayes LS Kawabata TT 《Science (New York, N.Y.)》2003,302(5646):875-878
Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings. 相似文献
93.
94.
Jagadeesh Mosali Kefyalew Desta Roger K. Teal Kyle W. Freeman Kent L. Martin Jason W. Lawles 《Journal of plant nutrition》2013,36(12):2147-2163
ABSTRACT One would expect foliar applied phosphorus (P) to have higher use efficiencies than when applied to the soil, but limited information is available concerning this. Experiments were conducted in 2002, 2003, and 2004 to determine the effect of foliar applications of P on winter wheat grain yields, P uptake, and use efficiency. Twelve treatments containing varying foliar P rates (0, 1, 2, and 4 kg ha? 1 in 2002 and 2003 and additional 8, 12, 16, and 20 kg ha? 1 in 2004) with and without pre-plant rates of 30 kg ha? 1 were evaluated. Foliar applications of P at Feekes 7 generally increased grain yields and P uptake versus no foliar P. Use efficiency was higher when P was applied at Feekes 10.54. Results from this study suggested that low rates of foliar applied P might correct mid-season P deficiency in winter wheat, and that might result in higher P use efficiencies. 相似文献
95.
A 140-day laboratory incubation, using surface soil from a long-term soybean tillage study, evaluated tillage influence on [14C]metribuzin degradation. Higher plant residue conditions in no-tillage (NT) soil inhibited metribuzin mineralization to [14C]carbon dioxide as compared to metribuzin degradation patterns observed in conventional tillage (CT) soil. At 140 days, relative abundance of extractable 14C components in NT included polar metabolites > metribuzin = deaminated metribuzin (DA) = deaminated diketometribuzin (DADK), while in CT, components included metribuzin > polar metabolites > DADK?DA. Conditions in NT apparently inhibited polar 14C degradation, and resulted in its accumulation, while in CT polar 14C degradation proceeded relatively rapidly. For both NT and CT, more 14 C was measured in an unextractable fraction than in any other fraction. A greater portion of the unextractable fraction in NT was associated with decomposed plant residue than in CT. Surface accumulation of crop residue, such as occurs under NT, provided a soil environment which altered metribuzin degradation patterns. 相似文献
96.
Martin CL 《Clinical Techniques in Small Animal Practice》2001,16(1):62-70
A good ocular examination and careful evaluation of the pupillary light reflexes will localize most lesion(s) producing a complaint of blindness. Lesions of the clear media severe enough to produce blindness will prohibit fundus examination. Retinal, optic nerve, and complete chiasmal lesions will produce dilated, slowly reactive pupils. Retinal blindness is usually associated with dramatic ophthalmoscopic lesions of diffuse altered reflectivity and vascular attenuation, the major exceptions being the sudden acquired retinal degeneration syndrome and some patients with glaucoma. Optic nerve lesions may involve the optic disc where they may be recognized by either pallor or hyperemia and cupping or elevation. Confirmation of optic nerve blindness in practice usually is by ruling out retinal blindness, but a more definitive methodology is to have a normal electroretinogram, slow or absent direct pupillary light reflexes (PLR), and abnormal visual evoked potentials. Central blindness is diagnosed by normal eyes, normal PLR, and often central nervous system (CNS) signs indicative of a diffuse or multifocal CNS disease. 相似文献
97.
Leontine T. Colon Dirk J. Budding L. C. Paul Keizer Martin M. J. Pieters 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(4):441-456
Four components of partial resistance toPhytophthora infestans were measured after inoculation in the greenhouse and in the field ofSolanum arnezii x hondelmannii, S. berthaultii, S. circaeifolium, S. leptophyes, S. microdontum, S. sparsipilum, S. sucrense andS. vernei, and four hybrid progenies ofS. microdontum withS. tuberosum. The four components were infection efficiency, lesion growth rate, generation time and sporulation capacity. The results were compared with resistance ratings derived from field experiments, and with observations made on the potato cultivars Bintje, Bildstar, Libertas and Pimpernel. Genetic variation for all components was found, while the relative importance of the components of partial resistance appeared to vary between the species. InS. microdontum, generation time, infection efficiency and lesion growth rate, and inS. tuberosum infection efficiency, lesion growth rate and sporulation capacity appeared positively associated, but in other species no such association was found. A strong hypersensitive reaction, the expression of which appeared to depend on environmental conditions, was found inS. microdontum. ForS. berthaultii, infection efficiency appeared to be the main resistance component.Abbreviations ADPC
area under the disease progress curve
- IE
infection efficiency
- LGR
lesion growth rate
- GT
generation time
- SC
sporulation capacity 相似文献
98.
Suzanne J. Clark Nicola P. Coward Glenn W. Dawson Ian F. Henderson Andrew P. Martin 《Pest management science》1995,44(4):381-388
Two related iron chelates, one toxic to slugs by ingestion, the other not, were introduced into the foregut of D. reticulatum. The subsequent movement and redistribution of the metal within the slug tissues was studied by labelling the chelates with the radioactive isotope 55Fe. In slugs which survived treatment approximately half of the 55Fe was voided in faeces. The iron retained became unevenly distributed, the highest concentration occurring in the digestive gland, irrespective of the chelate used. At high doses, slugs treated with tris(1-oxo-1,2-diazabutan-2-oxido)Fe(III) were fatally poisoned while those treated with the homologue, tris(1-oxo-1,2-diazaoctan-2-oxido)Fe(III) were not. Slugs killed by the toxic chelate consistently contained proportionally less iron in the digestive gland and proportionally more in the body wall and reproductive system. Dosing slugs already killed by carbon dioxide asphyxiation gave a similar pattern, suggesting that the greater mobility of the iron from the toxic chelate was not a function of the slugs' metabolism. 相似文献
99.
1. In south-western Australia, male and female emus decrease their food intake when they start breeding in early winter and increase their intake during spring and summer when the breeding season and egg incubation are finished. 2. This annual feeding cycle seems to be under the influence of several environmental factors. Here, we tested the importance of photoperiod using male emus kept in light-controlled rooms with ad libitum access to food and water. 3. Long days increased food intake whereas short days decreased it. Emus fed only during the light hours. 4. Frequency of meals was similar under the 2-day lengths but meal duration was shorter when the emus were on short days than when they were on long days. Thus, day length seemed to affect appetite but not interest in food. 5. Further investigations are needed to test whether these changes in feeding behaviour are a direct consequence of day length or if they are secondary to photoperiod-driven changes in sexual activity. 相似文献
100.
The effects of intercrop spacing patterns on the silage yields of both maize (lea mays L.) and soybean (Glycine max [L.] Merr.) were examined from 1985 to 1987. Dwarf maize was intercropped with nonnodulatmg or nodulating soybean in the spacing patterns, S40same (two crops in the same row, 40 cm row width) and S20ait or S40ak (two crops in alternate rows, 20 cm or 40 cm row width, respectively). Tall maize was intercropped with nodulating soybean in S40sames S40alt and S40pair (maize in 40 cm paired rows, soybean rows 20 cm outside each maize row and 80 cm from the next set of four rows) at 0 or 60 kg N ha−1 and at population densities of 67% maize: 67% soybean or 50 % maize: 50% soybean. Maize and soybean were also intercropped and stripcropped on a farm-scale. The only difference between intercrops arranged in the same rows versus those in alternate rows was that the average soybean protein yields were higher in S40same than in S40alt . In 1986, the S40alt maize-soybean intercrops produced higher maize yields, total biomass yields and Land Equivalent Ratios (LERs) than in S40pirs , and in 1987, these responses were higher in intercrops than in stripcrops. In 1986, at 0 kg N ha−1 , the soybean biomass and protein yields were lower in S40alt , than in S40pairs and in 1987, these responses were lower in intercrops than in stripcrops. 相似文献