In 3 urban areas in Selangor, Peninsular Malaysia between 1973 and 1981, blood from 4080 dogs was examined for haematozoa. The following frequencies were found: Babesia gibsoni 17.7%; microfilariae of Dirofilaria immitis 9.6%; Hepatozoon canis 1.2%; B. canis 1.1%; Ehrlichia canis 0.2%; Trypanosoma evansi 0.1%. A detailed examination of B. gibsoni infections and microfilariasis due to D. immitis with regards to monthly distribution, breed frequency, sex and age, revealed that pedigree and non-pedigree dogs were equally susceptible to Babesia and microfilariae infections. 相似文献
The history of scientific forest management in Bangladesh datesback to the nineteenth century with defined forest policiesand laws. Due to various socio-economic and socio-politicalfactors, forest cover of the country reduced drastically andall such policy initiatives proved ineffective. Although traditionalforest management objectives covered a wide range from economicbenefit to ecological stability, these have never been attainedfully. Huge population and limited land area compelled policymakers to think about alternatives to traditional forest management.One alternative, social forestry, was introduced in Bangladeshin early 1980s and has proved to be extremely successful. Whiletraditional forest management resulted in a net loss of forestresource cover, social forestry on the other hand, is playinga vital role in the expansion of forest cover (40 387 ha ofnew forest cover and 48 420 km new strip plantation since themid-1980s) benefiting thousands of poor people. Results showthat during the last four years (20002003) more than23 000 individuals benefited from the final felling of differentsocial forestry plantations (woodlot, agroforestry and stripplantation). This generated a total income of US$ 5.6 millionfor the government and US$ 5.3 million for participants plusUS$ 1.2 million for the Tree Farming Fund a 10 per centdepository reserve to sustain the practice in the long run.Although average individual final returns (US$ 223 person1)are not so attractive, some people got about US$ 5000 to US$8500 from final felling, sufficient to improve their standardof living and social position. Despite the success so far achieved,social forestry in Bangladesh still suffers from various institutionaldeficiencies like organization, skilled manpower, legitimateusufruct rights, peoples' participation from policy to implementationand clear budgetary arrangements. Besides, until now the roleof relevant actors is not well defined in all the steps of socialforestry practice in Bangladesh. Unless the participants aregiven clear legitimate usufruct rights, they will remain scepticaltowards this programme. They should have good and meaningfulaccess from planning to implementation. In the context of institutionaldevelopment, there are governmental policy guidelines and a20-year Master Plan for Bangladesh. Although some steps havebeen partially completed, there is still much to do to complywith forest policy guidelines and the Master Plan. It is shownthat in the last seven years (1995/962001/2002) onlyUS$ 15.41 million a1 has actually been spent againstan allocated sum of US$ 68.37 million a1. Therefore,if the intention is to institutionalize social forestry in Bangladesh,government and policy makers should actively come forward. Otherwisethe full potential of social forestry in Bangladesh will notbecome a reality. 相似文献
ABSTRACTThe relationship between stand attributes and biomass accumulation pattern in a mangrove forest has been intensively studied in this study. We assessed above (AGM) and belowground mass (BGM) and examined the relationship between forest attributes and aboveground mass in the Sundarbans, Bangladesh. The study was conducted with 18 plots having total area of 1.08 ha. The mean AGM and BGM of the study sites were 234.08 and 132.85 Mg ha?1 respectively. H. fomes contributed the highest amount (82.9% of total AGM and 80.53% of total BGM) of above (193.56 Mg ha?1) and belowground mass (107.09 Mg ha?1) at the study site. Our study revealed structural attributes (tree diameter, height, and basal area) positively correlated with AGM. In contrast, species richness and species diversity negatively correlated with AGM. Our study indicated that lack of positive relationship between species diversity and AGM which may be attributable to high AGM of the dominant species (H. fomes) and may have a considerable consequence in AGM of the study area. Thus, maintaining large trees (DBH and height) rather than species diversity in the Sundarbans mangrove forest might be an effective approach for increasing aboveground mass. 相似文献
The effect of intermittent heat treatment on cellulose crystallites in wood was studied to evaluate quantitatively the changes of crystallinity induced by intermittent and continuous heating. The changes in crystallinity were found to be strongly affected by the intermittent heat treatment. The increased crystallinity, the width of the crystals, and the piezoelectric properties were the same for the first intermittent heating as for continuous heating. Further intermittent heating for the same time duration and temperature had no effect on the above properties, probably due to the stopping of the thermal reaction during the interval. Our results suggested that intermittent heat treatment has certain critical cooling temperatures that stop the thermal reaction and are closely related to the duration of the interval. Samples once exposed to a certain duration of heat treatment and then cooled need more time, about twice that of the first duration of intermittent heating compared with continuous heating, to reach maximum crystallinity in wood cellulose. 相似文献
To obtain high-strength phenol formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, the effects of resin content, preheating temperature, pressing temperature, and pressing speed on the compressive deformation of oven-dried low molecular weight PF resin-impregnated wood was investigated. With an increase of PF resin content, the Youngs modulus of the cell wall perpendicular to the fiber direction decreases, and collapse-initiating pressure decreases linearly with the Youngs modulus. This indicates that the occurrence of cell wall collapse is strain-dependent. By increasing preheating temperatures, the collapse-initiating pressure increases due to the increment of the Youngs modulus of the cell wall. An increase in pressing temperature results in the thermal softening of the cell wall and causes collapse at a lower pressure. The wood is compressed effectively despite accelerated resin curing. The pressing speed significantly affects the viscoelastic deformation of the cell wall and the wood is well deformed with decreasing pressing speed, although the differences in density and mechanical properties are relatively small after a pressure-holding period of 30min. In all the parameters examined in this study, the Youngs modulus and bending strength increase with increasing density. 相似文献
Agroforestry Systems - Tropical agroforestry practices play a crucial role in mitigating global climate change by absorbing CO2 from the atmosphere through photosynthesis and storing carbon in... 相似文献
New Forests - Climate change is predicted to cause northward migration of boreal tree species. However, the success of such a migration will be determined by trees’ ability to acclimate to... 相似文献
Though Biofloc Technology is a new concept in Bangladesh, it provides advantages for improving aquaculture production in many countries, leading to achieve sustainable development goals. The objectives of this study were to determine the effects of stocking densities on the growth performance of stinging catfish (Heteropneustes fossilis) under Biofloc Technology and assess the economic prospects and business feasibilities. Fingerlings were stocked in unique 5000-L tanks with three stocking densities, i.e., 3500 fish/tank (Treatment-I), 4000 fish/tank (Treatment-II), 4500 fish/tank (Treatment-III). The treatments showed significant differences (P?<?0.05) considering the species-specific growth rate, feed conversion ratio, and protein efficiency ratio. Treatment-I had significantly ((P?<?0.05) higher final biomass (29.51 ± 0.04 kg/m3) than the other treatments. The present findings revealed that using a lower stocking density, the Biofloc Technology reduced ammonia (NH3), nitrite (NO2), nitrate (NO3), TDS, and floc volume but significantly increased the dissolved oxygen. As a result, Treatment-I had generated significantly higher net income (BANGLADESHI TAKA—BDT 86,278.90) over the other treatments. Moreover, the NPV, net BCR, and RoR with 4% and 9% opportunity cost were also significantly higher in Treatment-I than other treatments. The internal rate of return (IRR) and SWOT analysis index indicates that investing in Biofloc Technology is far superior, and a stocking density of 3500 fish/tank (Treatment-I) resulted in a faster investment return.