Co-management and Labor Stickiness in Fishing Communities: Determination of the Optimal Number of Vessels

In the recent years, resource depletion of inshore and coastal fisheries has seriously impacted Taiwan. Local fishing communities’ economic profits in these fisheries have declined and resulted in lower earned incomes for the fishermen. These phenomena have lead many scholars, government agencies and fishing communities to evaluate the optimal number of operating vessels in these fisheries. This study has explicitly applied the concepts of community-based co-management, fish market concentration and labor stickiness to an economic model that can be used to determine the optimum number of fishing vessels in a fishing community. One corollary of this approach is that we modify the traditional assumption regarding labor mobility in a fishing community and explore here how labor stickiness to the extent that it exists in Taiwan’s fishing communities might bias traditional fishing management policies and influence the determination of optimal number of vessels. In addition, the Herfindahl index (H), which measures the degree of concentration in the structure of a fishery market, will also affect the final determination of the optimal number of vessels. Results suggest that when there are no labor mobility barriers, then with flexible fishing operation costs, the optimal number of vessels and the fish stock would be smaller. Larger values of H (i.e., Herfindahl index) and greater differentials in the fishing efficiency index in the fishing community also result in relatively fewer vessels and fish stock. Finally, as to the impacts of changing fish stock growth rate and fish price on the optimal vessel number and fish stock are also discussed.Keywords: community-based co-management, labor stickiness, market concentratio

Chemical Constituents of Phaius mishmensis

The partitioned n-hexane, CHCl3, and EtOAc extracts from the crude MeOH extract of Phaius mishmensis showed considerable cytotoxicities against the human breast carcinoma (MCF-7), lung carcinoma (NCI-H460), and central nervous system carcinoma (SF-268) cell lines. Four new compounds, phaindole (1), (7′R,8′R)-phaithrene (2), methyl 3-hydroxy-4,5-dimethoxypropiophenone (3), and methyl hematinate (4), as well as 44 known compounds were isolated from the MeOH extract of Phaius mishmensis. The structures of the compounds were determined using spectroscopic methods

Synthesis, Experimental and Density Functional Theory (DFT) Studies on Solubility of Camptothecin Derivatives

Two camptothecin derivatives, 10-cyclohexyl-7-methyl-20(S)-camptothecin and 7-methyl-10-morpholino-20(S)-camptothecin, were synthesized and their differences in solubility were investigated using four chosen solvent systems. Based on our results, 10-cyclohexyl-7-methyl-20(S)-camptothecin exhibited higher solubilities than 7-methyl-10-morpholino-20(S)-camptothecin in polar aprotic solvents. However, these two camptothecin derivatives did not exhibit apparent differences in solubility between 5% dimethyl sulfoxide (DMSO)/95% normal saline co-solvent system and 5% dimethylacetamide (DMAC)/95% normal saline co-solvent system. To rationalize their differences in solubility, we also tried to perform a DFT-B3LYP study to investigate their interaction with one water molecule

Chemical Constituents and Biological Studies of the Leaves of Grevillea robusta

Three new compounds: Graviquinone (1), cis-3-hydroxy-5-pentadecylcyclohexanone (2), and methyl 5-ethoxy-2-hydroxycinnamate (3), and thirty-eight known compounds were isolated and identified from the leaves of Grevillea robusta. The structures of these compounds were determined by spectroscopic and chemical transformation methods. Graviquinone (1) showed the strongest cytotoxicity against MCF-7, NCI-H460, and SF-268 cell lines. Methyl 2,5-dihydroxycinnamate (4), graviphane (13), and dehydrograviphane (14) exhibited very potent DPPH scavenging activity compared with α-tocopherol. Methyl 2,5-dihydroxycinnamate (4) and bis-norstriatol (17) demonstrated strong inhibition of L-DOPA oxidation by mushroom tyrosinase compared with kojic acid

Structure-Activity Relationship of Synthetic 2-Phenylnaphthalenes with Hydroxyl Groups that Inhibit Proliferation and Induce Apoptosis of MCF-7 Cancer Cells

<div><p>In this study, six 2-phenylnaphthalenes with hydroxyl groups were synthesized in high yields by the demethylation of the corresponding methoxy-2-phenylnaphthalenes, and one 2-phenylnaphthalene with an amino group was obtained by hydrogenation. All of the 2-phenylnaphthalene derivatives were evaluated for cytotoxicity, and the structure-activity relationship (SAR) against human breast cancer (MCF-7) cells was also determined. The SAR results revealed that cytotoxicity was markedly promoted by the hydroxyl group at the C-7 position of the naphthalene ring. The introduction of hydroxyl groups at the C-6 position of the naphthalene ring and the C-4<b>'</b> position of the phenyl ring fairly enhanced cytotoxicity, but the introduction of a hydroxyl group at the C-3<b>'</b> position of the phenyl ring slightly decreased cytotoxicity. Overall, 6,7-dihydroxy-2-(4'-hydroxyphenyl)naphthalene (<b>PNAP</b>-<b>6h</b>) exhibited the best cytotoxicity, with an IC₅₀ value of 4.8 μM against the MCF-7 cell line, and showed low toxicity toward normal human mammary epithelial cells (MCF-10A). <b>PNAP</b>-<b>6h</b> led to cell arrest at the S phase, most likely due to increasing levels of p21 and p27 and decreasing levels of cyclin D1, CDK4, cyclin E, and CDK2. In addition, <b>PNAP</b>-<b>6h</b> decreased CDK1 and cyclin B1 expression, most likely leading to G₂/M arrest, and induced morphological changes, such as nuclear shrinkage, nuclear fragmentation, and nuclear hypercondensation, as observed by Hoechst 33342 staining. <b>PNAP</b>-<b>6h</b> induced apoptosis, most likely by the promotion of Fas expression, increased PARP activity, caspase-7, caspase-8, and caspase-9 expression, the Bax/Bcl-2 ratio, and the phosphorylation of p38, and decreased the phosphorylation of ERK. This study provides the first demonstration of the cytotoxicity of PNAPs against MCF-7 cells and elucidates the mechanism underlying PNAP-induced cytotoxicity.</p></div