Environmental impact assessment of the pangasius sector in the Mekong Delta

In the past seven years the export of white pangasius fillets grew fast. The culture method shifted to intensive production of striped catfish (Ca Tra) in deep ponds because this is more efficient than the pen and cage culture of Ca Basa. Today, striped catfish comprises more than 90 % of the culture. The increased production was achieved by producers investing in large ponds. The market chain is gearing towards vertical integration. Most farms keep fish at relatively high densities of 15 to 25 fish/m3 in ponds having a depth of up to 4m, and are advised to exchange daily 20 to 40% of the water. The sustainability of the sector is threatened due to the increased environmental pressure, and hampered by the growing cost of inputs and reduced farm-gate prices of the fish. The Environmental Impact Assessment (EIA) intends to identify measures for preventing or mitigating the environmental impacts of catfish culture in the Mekong Delta. The EIA was a seven-step process during which we interacted twice with part of the main stakeholders. To build trust among the stakeholders from the sector, we conducted the scoping and goal setting with them

On the boundedness of the Hardy operator in the weighted space BMO

The result of Golubov [5, Theorem 2] on the boundedness of the Hardy-Littlewood operator Bf(x) := 1/x integral(x)(0)f(x)dt in the space BMO(R) is well known. The author of the present paper solves the analogous problem in the weighted space BMO on the semi-axis R(+) for the operator T(w)f(x) := 1/W(x) integral(x)(0)f(t)w(t)dt, and also in the classical space BMO(R(+)) for a class of integral operators involving, for example, the Riemann-Liouville fractional integral

On the boundedness of the Hardy operator in the weighted space BMO

The result of Golubov [5, Theorem 2] on the boundedness of the Hardy-Littlewood operator Bf(x) := 1/x integral(x)(0)f(x)dt in the space BMO(R) is well known. The author of the present paper solves the analogous problem in the weighted space BMO on the semi-axis R(+) for the operator T(w)f(x) := 1/W(x) integral(x)(0)f(t)w(t)dt, and also in the classical space BMO(R(+)) for a class of integral operators involving, for example, the Riemann-Liouville fractional integral

Morphological Alterations of Fish Erythrocytes as Their Response to Environmental Conditions

Fish bodies respond to changes in environmental conditions in various ways and degrees. Seven fish species were collected from three study locations, including two nearshore sites (Ha Tinh province and Nha Trang city, Khanh Hoa province) and one offshore site (Toc Tan island, Khanh Hoa province) to evaluate alterations in erythrocyte morphology under certain environmental conditions. Heavy metal concentrations at all study sites were analyzed and met the acceptable technical criteria for each site. Fish blood samples were taken from the tail veins, anticoagulated with heparin, and stained with Giemsa stain. The blood cell morphological study was performed using an optical microscope. The results revealed two types of morphological abnormalities of fish erythrocytes, including nuclear deformation and nuclear-matter distribution

Volatile constituents of the leaf, stem, rhizome, root and flower oils of Curcuma harmandii Gagnep. from Vietnam

The volatile oils from Curcuma harmandii Gagnep. (Zingiberaceae), obtained by steam distillation of the fresh leaves, stems, small and large rhizomes, roots and flowers, were examined by high resolution GC and GC/MS. All oils contained substantial fractions of sesquiterpenes and oxygenated terpenes. The major components of the leaf and stem oils were 1,S-cineole (13.5% and 21.S%), germacrone (11.5% and 15.5%) and curdione (36.S% and 25.3%). The oils from the small and large rhizomes also contained ItS-cineole (12.5% and 4.5%) and germacrone (9.0% and 20.5%) as main constituents, in addition to l3-pinene (22.6% and 1.2%), l3-elemene (11.3% and 6.5%) and isocurcumenol (3.7% and 13.4%). The root oil was rich in germacrone (24.4%), isocurcumenol (12.9010) and curcumenoi (lO.S%). The major constituents of the flower oil were curdione (27.0%) and an unidentified oxygenated sesquiterpene with a molecular mass of 234 Da (12.3%). This particular oil consisted for more than 90% of sesquiterpenes and oxygenated components, which contribute to the special odor of the flower oil

Volatile constituents of the essential oil of Curcuma trichosantha Gagnep. from Vietnam

The volatile rhizome oil of Curcuma trichosantha Gagnep. from Vietnam was analyzed by capillary GC and GC/MS. The main constituents were found to be curdione (47.4%), curcumol (7.0%) and germacrone (6.1%). The structure elucidation of curdione was confirmed by IR, 1H- and 13C-NMR spectrometr