592 research outputs found
Development of freshwater prawn (Macrobrachium rosenbergii) seed production and culture technology in the Mekong Delta Region of Vietnam: A review of the JIRCAS Project at Cantho University.
The Mekong Delta of Vietnam is a region rich in aquatic resources having high potential for aquaculture development. Inland aquaculture in the Mekong Delta has greatly increased since the last decade. Fish culture carried out in combination with other agricultural activities such as animal husbandry and rice cultivation, and intensive aquaculture in ponds and cages have been the dominant forms of fish production. However, the giant freshwater prawn, Macrobrachium rosenbergii, has recently become a species of economic significance and the target of aquaculture activity in the Mekong Delta. M. rosenbergii is cultured throughout the region in the rice fields, ponds, orchard gardens and in pens along river banks. The major constraints in this industry are seed supply and culture techniques, becoming the major obstacles for the further development of the culture of this species.
In a collaborative research project implemented between the Japan International Research Center for Agricultural Sciences (JIRCAS) and Cantho University (CTU) since 1994, studies have been carried out on various aspects relating to the establishment of M. rosenbergii seed production and culture technology. The project is now in the middle of its second phase and has generated a great deal of scientific and practical information. This paper presents an overview of the achievements of this project
La fonction de partition de Minc et une conjecture de Segal pour certains spectres de Thom
On construit dans cet article une résolution injective minimale dans la catégorie \U des modules instables sur l'algèbre de Steenrod modulo , de la cohomologie de certains spectres obtenus à partir de l'espace de Thom du fibré, associé à la représentation régulière réduite du groupe abélien élémentaire , au dessus de l'espace . Les termes de la résolution sont des produits tensoriels de modules de Brown-Gitler et de modules de Steinberg introduits par S. Mitchell et S. Priddy. Ces modules sont injectifs d'après J. Lannes et S. Zarati, de plus ils sont indécomposables. L'existence de cette résolution avait été conjecturée par Jean Lannes et le deuxième auteur. La principale indication soutenant cette conjecture était un résultat combinatoire de G. Andrews : la somme alternée des séries de Poincaré des modules considérées est nulle
Theoretical modeling of the carbon dioxide injection into the porous medium saturated with methane and water taking into account the CO2 hydrate formation
In this work the mathematical model is constructed and the features of the injection of warm carbon dioxide (with the temperature higher than the initial reservoir temperature) into the porous reservoir initially saturated with methane gas and water are investigated. Self-similar solutions of the one-dimensional problem describing the distributions of the main parameters in the reservoir are constructed. The effect of the parameters of the injected carbon dioxide and the reservoir on the intensity of the CO2hydrate formation is analyzed
A Novel Approach in Crude Enzyme Laccase Production and Application in Emerging Contaminant Bioremediation
Laccase enzyme from white-rot fungi is a potential biocatalyst for the oxidation of emerging contaminants (ECs), such as pesticides, pharmaceuticals and steroid hormones. This study aims to develop a three-step platform to treat ECs: (i) enzyme production, (ii) enzyme concentration and (iii) enzyme application. In the first step, solid culture and liquid culture were compared. The solid culture produced significantly more laccase than the liquid culture (447 vs. 74 µM/min after eight days), demonstrating that white rot fungi thrived on a solid medium. In the second step, the enzyme was concentrated 6.6 times using an ultrafiltration (UF) process, resulting in laccase activity of 2980 µM/min. No enzymatic loss due to filtration and membrane adsorption was observed, suggesting the feasibility of the UF membrane for enzyme concentration. In the third step, concentrated crude enzyme was applied in an enzymatic membrane reactor (EMR) to remove a diverse set of ECs (31 compounds in six groups). The EMR effectively removed of steroid hormones, phytoestrogen, ultraviolet (UV) filters and industrial chemical (above 90%). However, it had low removal of pesticides and pharmaceuticals.</jats:p
Innovative in silico approaches to address avian flu using grid technology
The recent years have seen the emergence of diseases which have spread very
quickly all around the world either through human travels like SARS or animal
migration like avian flu. Among the biggest challenges raised by infectious
emerging diseases, one is related to the constant mutation of the viruses which
turns them into continuously moving targets for drug and vaccine discovery.
Another challenge is related to the early detection and surveillance of the
diseases as new cases can appear just anywhere due to the globalization of
exchanges and the circulation of people and animals around the earth, as
recently demonstrated by the avian flu epidemics. For 3 years now, a
collaboration of teams in Europe and Asia has been exploring some innovative in
silico approaches to better tackle avian flu taking advantage of the very large
computing resources available on international grid infrastructures. Grids were
used to study the impact of mutations on the effectiveness of existing drugs
against H5N1 and to find potentially new leads active on mutated strains. Grids
allow also the integration of distributed data in a completely secured way. The
paper presents how we are currently exploring how to integrate the existing
data sources towards a global surveillance network for molecular epidemiology.Comment: 7 pages, submitted to Infectious Disorders - Drug Target
Optically reconfigurable molecules of topological bound states in the continuum
Symmetry protected optical bound states in the continuum (BICs) are charming
wave-mechanical objects that provide new and exciting ways to enhance
light-matter interactions in compact photonic devices. These ultrahigh quality
factor states have quickly transcended from passive structures, and lasing
devices in the weak-coupling regime, towards nonequilibrium Bose-Einstein
condensates of BIC polaritons in the strong-coupling regime. Here, we show that
the large interaction strength of exciton-polaritons in subwavelength
quantum-well waveguide gratings in conjunction with their topologically
protected BIC nature opens unexplored opportunities in low-threshold optically
reprogrammable quantum fluids. The BIC causes polaritons to -- almost
counterintuitively -- condense in the extremum of a negative mass dispersion
which leads to strong interaction-induced trapping at their respective pump
spot and gain region. We exploit this optical trapping mechanism to demonstrate
macroscopic mode-hybridization, the hallmark of coherent quantum systems,
enabling construction of never-seen-before artificial BIC molecules with
unusual topological charge mutliplicity. We underpin the optical write-in
aspect of our technique by constructing, on the same sample, artificial
mono-atomic and dimerized BIC chains of polariton fluids displaying
non-Hermitian quasicrystalline band formation and gap opening. Our findings
open new perspectives on large-scale reprogrammable driven dissipative
many-body systems in the strong-coupling regime
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