Factors influencing the sustained participation of farmers in participatory forestry: a case study in central Sal forests in Bangladesh

Wide acceptance of sustainable development as a concept and as the goal of forest management has shifted forest management policies from a traditional to a people-oriented approach. Consequently, with its multiple new objectives, forest management has become more complex and an information gap exits between what is known and what is utilized, which hinders the sustained participation of farmers. This gap arose mainly due to an interrupted flow of information. With participatory forestry, the information flow requires a broad approach that goes beyond the forest ecosystem and includes the different stakeholders. Thus in participatory forest management strategies, policymakers, planners and project designers need to incorporate all relevant information within the context of the dynamic interaction between stakeholders and the forest environment. They should understand the impact of factors such as management policies, economics and conflicts on the sustained participation of farmers. This study aimed to use primary cross-sectional data to identify the factors that might influence the sustained participation of farmers in participatory forestry. Using stratified random sampling, 581 participants were selected to take part in this study, and data were collected through a structured questionnaire by interviewing the selected participants. To identify the dominant factors necessary for the sustained participation of farmers, logistic regression analyses were performed. The following results were observed: (a) sustained participation is positively and significantly correlated with (i) satisfaction of the participants with the tree species planted on their plots; (ii) confidence of the participants that their aspired benefits will be received; (iii) provision of training on different aspects of participatory forestry; (iv) contribution of participants' money to Tree Farming Funds. (b) The sustained participation of farmers is negatively and significantly correlated with the disruption of local peoples' interests through implementation of participatory forestry programs, and long delays in the harvesting of trees after completion of the contractual agreement period.     

Molecular size as a limiting characteristic for bioconcentration in fish

The relationships between the bioconcentration factor (BCF) of chemicals in fish and their size, as characterized by molecular weight (MW), effective cross sectional diameter (Deff), and maximum diameter (Dmax) have been investigated using an experimental data set of 737 new and 441 existing chemicals monitored by the Japanese Chemical Substances Control Law (CSCL). Substances with BCF > or = 5000 (very high bioconcentration potential) typically have MW < 550, Deff < 1.1 nm and Dmax < 2.0 nm, respectively and the substances with BCF > or = 1000 (high bioconcentration potential) have MW < 550, Deff < 1.4 nm and Dmax < 2.9 nm, respectively Therefore, the previously suggested threshold values for Deff (0.95 nm) and Dmax (1.5 nm) used for discriminating between bioconcentrative and non-bioconcentrative substances were found to be somewhat small. We found that many substances with BCF > or = 1000 and Dmax > or = 1.5 nm have Deff < 0.95 nm.     

Distribution of tetrodotoxin in various organs of the starfish Astropecten polyacanthus

Tissues of various organs of the starfish Astropecten polyacanthus collected in the Hiroshima Prefecture from April 1985 to June 1986 were analyzed for lethal potency by the assay method for tetrodotoxin. The ovary showed the highest potency (47 to 1 450 MU g^-1), followed by the digestive organs (<10 to 960 MU g^-1) and the exoskeleton including spines and tube-feet (<10 to 170 MU g^-1). The pyloric caecum and testis were less toxic. Overall toxicity was remarkably higher in females (2 060±382 MU, mean±SE) than in males (1 106±214 MU).     

Changes in microflora of a puffer fish Fugu niphobles,with different water temperatures

Grass puffer Fugu niphobles, captured in November 1986 at Shimoda, Japan, and then reared at different temperatures ranging from 10 to 29°C, was examined for microflora changes in the skin, gill and intestines. At 10°C, the skin and gill were colonized mainly by Pseudomonas, Flavobacterium and Moraxella, while at 29°C Vibrio and Flavobacterium appeared abundantly. The intestinal microflora, consisting of Vibrio, Pseudomonas and Flavobacterium, revealed little temperature dependence, although the intrageneric composition of Vibrio changed conspicuously depending on the change of water temperature. Vibrio group 1, tentatively identified as V. alginolyticus, was detected in all tissues examined at 20 and 29°C. This, along with the fact that V. alginolyticus produces tetrodotoxin, suggests that the tetrodotoxin contained in puffer is, at least partly, accounted for by this bacterial species inhabiting intestines.     

Occurrence of tetrodotoxin in the starfishes Astropecten polyacanthus and A. scoparius in the Seto Inland Sea

Two starfishes, togemomijigai Astropecten polyacanthus and momijigai A. scoparius were collected from the Seto Inland Sea in October 1983 through November 1984, and assayed for toxicity by the standard method for tetrodotoxin (TTX). Most of the 54 A. polyacanthus specimens assayed were toxic, with the highest toxicity score being 520 mouse units (MU) g^-1. All seven A. scoparius were toxic, with the highest score being 46 MU g^-1. The toxin from A. polyacanthus was purified by a method which consisted mainly of activated charcoal treatment, and chromatography on CM-Sephadex C-25 and Bio-Rex 70 columns. The purified starfish toxin showed a specific toxicity of 4 700 MU mg^-1, a value which was almost comparable to that of authentic TTX. From the thin-layer chromatographic and electrophoretic behavior, along with ¹H-NMR spectrum, A. polyacanthus toxin was identified as TTX.     

Vibrio alginolyticus,a tetrodotoxin-producing bacterium,in the intestines of the fish Fugu vermicularis vermicularis

The influence of nutrient deprivation on cell-cycle progression was examined in two phytoplankton species, the diatom Thalassiosira weissflogii (actin) and the coccolithophorid Hymenomonas carterae (cocco II). The diatom was starved for nitrogen, silicon or both, whereas only nitrogen limitation was examined in H. carterae. In both species, nitrogen-starved cells were arrested in the early part of the cell cycle (G₁ phase). In the diatom, silicon-starvation arrested cells in late G₁ phase and also in the last part of the cell cycle (G₂+M). In all cases, cell-cycle arrest could be reversed by addition of fresh medium, but cell-cycling times during the first generation were increased in comparison to those in nutrient replete, steady-state growth conditions. These results supply evidence for simultaneous dual-nutrient limitation of population growth and provide a mechanistic interpretation for the division patterns observed in cultures where nutrients are supplied periodically.     

Accumulation of Hg and other heavy metals in the Javan mongoose (Herpestes javanicus) captured on Amamioshima Island, Japan

Concentrations of 22 elements (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, total Hg (T-Hg), Pb) and organic Hg (O-Hg) were examined in the liver, kidney and brain of the Javan mongoose (Herpestes javanicus) and in liver of the Amami rabbit (Pentalagus furnessi) from Amamioshima Island in Japan. Relatively high levels of T-Hg levels (from 1.75 to 55.5 microg g-1 wet wt.) were found in the Javan mongoose. As for a comparison of hepatic T-Hg concentrations between the two areas, there was no significant difference between the Javan mongoose in Amamioshima and those in the Okinawa islands. In addition, T-Hg levels in the livers of the Amami rabbit were the same as in the livers of other herbivorous mammals. Taken together, it suggested that T-Hg accumulation in the livers of the Javan mongoose was not affected by the environment but by a specific physiological mechanism. The comparison of Hg and other heavy metal accumulations between terrestrial mammals (13 species, 61 individuals) including the Javan mongoose and marine mammals (18 species, 508 individuals) were also discussed.     

Explosion properties of highly concentrated ozone gas

The explosive self-decomposition characteristics of gaseous ozone with a concentration of up to almost 100 vol% were quantitatively investigated using a closed system with an electric spark device. The lower self-decomposition (explosion) limit for ozone diluted with oxygen at room temperature and atmospheric pressure was 10–11 vol%, and so ozone at more than 10–11 vol% will lead to an explosive chain decomposition reaction leading to its complete conversion to oxygen in a vessel. The lower explosion limit shifts to a higher concentration with a decrease in pressure. The limit was about 80 vol% under a reduced pressure of 10 Torr. We also confirmed that explosion trigger energy (minimum ignition energy) is strongly dependent on ozone concentration and pressure. For example, the minimum trigger energy for 15 vol% ozone at a pressure of 76 Torr (about 220 mJ) was more than 20-fold that at atmospheric pressure (about 10 mJ), and that for 13 vol% ozone (about 580 mJ) was approximately 30 times higher than that for 20 vol% (about 20 mJ) at the same pressure of 76 Torr. Moreover, the physical characteristics of the trigger energy sources (e.g. spark gap and electrode tip angle) leading to the decomposition (explosion) of ozone were investigated under various conditions.     

Comparison of trace element accumulation in Baikal seals (Pusa sibirica), Caspian seals (Pusa caspica) and northern fur seals (Callorhinus ursinus)

Concentrations of 18 trace elements (V, Cr, Mn, Co, Cu, Zn, Se, Rb, Sr, Zr, Mo, Ag, Cd, Sb, Cs, Hg, Tl and Pb) were determined in liver, kidney, muscle and hair of Baikal seals, Caspian seals and northern fur seals. All the three species showed the highest concentrations of Hg, V, Mn, Se and Ag in liver, Cd, Co and Tl in kidney, and Cs in muscle among the soft tissues examined. The highest burdens of Zn, Rb and Cs were observed in muscle, Mo and Ag in liver, and Sb and Pb in hair in all the three species. Concentrations of non-essential elements, Rb, Cd, Cs and Hg, showed significant positive correlations among liver, kidney and muscle, whereas correlation coefficients for essential elements, Mn, Co, Cu, Zn and Se, between the three tissues were generally low for all the species, suggesting that homeostasis controls the concentrations of essential elements but not the non-essential elements in the tissues of these animals. Significant age-dependent increase was found in the concentrations of V, Se and Ag in liver and Hg in liver and kidney of all the three species. Hair concentrations showed significant positive correlations with Zn levels in liver and kidney and Hg in muscle for Caspian seals, Hg in liver and kidney for Baikal seals, and Pb in liver for northern fur seals. Furthermore, regression analysis using the data in the present study and in the literature showed significant positive correlations between Hg levels in hair, and liver, kidney and muscle for various species of pinnipeds. These results indicate the possibility of using hair samples for monitoring these trace elements in pinnipeds.