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71.
The ethanol extract of P. kamstchandalis as well as ethyl haematommate, ethyl-2,4-dihydroxy-6-methylbenzoate and methyl-β-orsellinate isolated from it exhibited varying degrees of antibacterial activity.  相似文献   
72.
Although trade liberalization may increase a country’s welfare, its specific effect on a country’s fishing industry has not been well studied. By decomposing the effect of international trade into four parts, i.e., scale-technique effects (ST), the indirect trade-induced composition effect (IC), the indirect effect of trade intensity through income (ITC), and the direct effect of trade intensity (DTC), this study empirically investigates the effect of trade openness on country-level fisheries production. To take into account the endogeneity of trade openness and income, we adopt the instrumental variable approach. We find that a rise in trade openness reduces fisheries catch on average. In particular, the long-run effect is large. This result implies that future production is affected by current overfishing through stock dynamics. Our decomposed elasticities indicate that the ST and ITC dominate in the trade elasticity of fisheries catch. While ST implies that overfishing would be affected by trade, ITC may either establish an “overfishing haven”, similar to a “pollution haven” in the environmental literature, or production shift of fisheries to countries with lax regulation to pass stringent regulation, which is more likely to occur in high-income countries.  相似文献   
73.
Fisheries Science - Fisheries subsidies have attracted considerable attention worldwide since the 1990s. The World Trade Organization (WTO), among others, started to strengthen its disciplines in...  相似文献   
74.
For many commercial fisheries, reductions in fishing effort would likely result in higher long-term catches and improved incomes per fisherman. But fishing licenses are perceived as though they were property rights, which can imply relatively high costs for publicly funded buyback programmes to reduce fishing effort. Instead of the public buying out fishing licenses, it can make good business sense for license holders to expect the public to pay for protection against new licenses, and to proceed under this protection to finance buybacks of licenses themselves. The short-run costs of such an investment are outweighed by long-term gains in annual incomes and the transfer value of licenses at the time of individual retirement, especially in fisheries that are severely overfished.  相似文献   
75.
The combination of a rising population and increased food demand has placed tremendous pressure on the land resources of Bangladesh. These pressures are exacerbated by the annual wet-season floods which frequently devastate much of the agricultural land. Successive governments have therefore sought international aid to assist in the development of flood control measures. Of particular importance are 14 major schemes which aim to provide protection from 20–25 year return floods by the construction of earth-embanked enclosures. There is no doubt that these schemes have been very successful in protecting valuable agricultural areas from floods and hence increasing agricultural production. There is, however, growing evidence from a range of sources for long-term deterioration in soil fertility within the project areas. The study reported here is the first to systematically examine the changes taking place in soil properties following the establishment of a flood control, drainage and irrigation project. Comparison of two soil series, sampled from within and without the project area, demonstrate that within six years of project establishment, significant adverse changes have occurred in several soil properties; these include increasing acidity and a decline in available nutrients. The changes are attributable to a combination of poor management strategies and the absence of the annual flood input of silt. As Bangladesh cannot afford any decline in agricultural output, it is vital to establish whether adverse changes recorded here are occurring in other projects. This can be achieved by the establishment of a nationwide programme of soil fertility monitoring. © 1998 John Wiley & Sons, Ltd.  相似文献   
76.
The anatomy of the auricular conchae of ruminants has been studied by intravascular injection of radiopaque latex, by dissection and by histological sectioning. Drawings were made of the vascular network. The arrangement of nerves and blood vessels in association with the ridges on the rostral (concave) surface was observed. The spaces between the ridges are relatively free of larger blood vessels, nerves, hair and sebaceous glands. This distribution is discussed in relation to the insertion of ear tags.  相似文献   
77.
Clubroot, caused by Plasmodiophora brassicae, has become a serious threat to canola (Brassica napus) production in western Canada. Experiments were conducted to assess the effect of growing resistant and susceptible canola genotypes on P. brassicae soil resting spore populations under greenhouse, mini‐plot and field conditions. One crop of susceptible canola contributed 1·4 × 108 spores mL?1 soil in mini‐plot experiments, and 1 × 1010 spores g?1 gall under field conditions. Repeated cropping of susceptible canola resulted in greater gall mass compared to resistant canola lines. It also resulted in reduced plant height, increased clubroot severity in susceptible canola, and increased numbers of resting spores in the soil mix.  相似文献   
78.
Background: Forests are fundamental in maintaining water supplies, providing economic goods, mitigating climate change, and maintaining biodiversity, thus providing many of the world’s poorest with income, food and medicine.Too often, forested lands are treated as "wastelands" or "free" and are easily cleared for agricultural and infrastructure expansion.Methods: In this paper, the sustainability of two forest ecosystems(state and community/private owned) was evaluated using SPOT-5 satellite images of 2005 and 2011. This study was conducted in a sub-watershed area covering 468 km2, of which 201 km2 is managed by the state and 267 km2 by community/private ownership in the Murree Galliat region of Punjab Province of Pakistan. A participatory approach was adopted for the delineation and demarcation of forest boundaries. The Geographic Object-Based Image Analysis(GEOBIA) technique was used for identification and mapping of ten Land Cover(LC) features.Results: The results show that between the years 2005 to 2011, a total of 55 km2(24 km2 in state-owned forest and 31km2 in community/private forest) was converted from forest to non-forest. The conclusion is that conservation is more effective in state-owned forests than in the community/private forests.Conclusions: These findings may help to mobilize community awareness and identify effective initiatives for improved management of community/private forest land for other regions of Pakistan.  相似文献   
79.
Development of Yellow Seeded Brassica napus Through Interspecific Crosses   总被引:12,自引:0,他引:12  
A. Rashid    G. Rakow  R. K. Downey 《Plant Breeding》1994,112(2):127-134
Yellow seeded Brassica napus was developed through interspecific crosses with the two mustard species, B. juncea and B. carinata. The objective of these two interspecific crosses was the introgression of genes for yellow seed colour from the A genome of B. juncea and C genome of B. carinata into the A and C genomes of B. napus, respectively. The interspecific F1 generations were backcrossed to B. napus in an attempt to eliminate B genome chromosomes and to improve fertility. Backcross F2 plants of the (B. napus×B. juncea) ×B. napus cross were then crossed with backcross F2 plants of the (B. napus×B. carinata) ×B. napus cross. The objective of this intercrossing was to combine the A and C genome yellow seeded characteristics of the two backcross populations into one genotype. The F2 generation of the backcross F2 intercrosses was grown in the field, plants were individually harvested and visually rated for seed colour. Ninety-one yellow seeded plants were identified among the 4858 plants inspected. This result indicated that the interspecific crossing scheme was successful in developing yellow seeded B. napus.  相似文献   
80.
ABSTRACT

Climate change is imposing high temperature resulting in prolonged drought episodes and shrinking of fresh water resources across the globe. In this scenario, even drought tolerant crops like quinoa are also losing significant yield. However, this study was planned to investigate the impact of drought on quinoa at critical growth stages and bacterial inoculation to improve drought tolerance. Drought was imposed by maintaining 25% pot water holding capacity (PWC) at multiple leaf, flowering, and seed filling stage (DSFS), while 80% PWC was considered as control. Three strains of plant growth promoting rhizobacteria (PGPR) named as: Bacillus licheniformis, Pseudomonas fluorescens, and Azospirillum brasilense were inoculated with quinoa seeds before sowing with respect to drought treatments. PGPR inoculation mitigated the drastic effects of drought by improving crop growth, net assimilation rate, water use efficiency, leaf chlorophyll, and phenolic contents, all of these ultimately contributed to improvement in grain yield and its contributing attributes. Moreover, PGPR markedly improves the grain quality attributes including protein, phosphorus, and potassium contents. Principal component analysis linked the different scales of study and demonstrated the potential of physio-biochemical traits to explain the quinoa yield variations under drought condition with response to PGPR inoculation. Among different PGPR, A. brasilense was found most effective both under normal and drought conditions. Overall, DSFS has more detrimental effects among critical growth stages of quinoa and A. brasilense can be used as a shotgun tactic to ameliorate drought stress in quinoa.  相似文献   
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