4,061 research outputs found

    Was the Higgs boson discovered?

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    The standard model has postulated the existence of a scalar boson, named the Higgs boson. This boson plays a central role in a symmetry breaking scheme called the Brout-Englert-Higgs mechanism (or the Brout-Englert-Higgs-Guralnik-Hagen-Kibble mechanism, for completeness) making the standard model realistic. However, until recently at least, the 50-year-long-sought Higgs boson had remained the only particle in the standard model not yet discovered experimentally. It is the last but very important missing ingredient of the standard model. Therefore, searching for the Higgs boson is a crucial task and an important mission of particle physics. For this purpose, many theoretical works have been done and different experiments have been organized. It may be said in particular that to search for the Higgs boson has been one of the ultimate goals of building and running the LHC, the world's largest and most powerful particle accelerator, at CERN, which is a great combination of science and technology. Recently, in the summer of 2012, ATLAS and CMS, the two biggest and general-purpose LHC collaborations, announced the discovery of a new boson with a mass around 125 GeV. Since then, for over two years, ATLAS, CMS and other collaborations have carried out intensive investigations on the newly discovered boson to confirm that this new boson is really the Higgs boson (of the standard model). It is a triumph of science and technology and international cooperation. Here, we will review the main results of these investigations following a brief introduction to the Higgs boson within the theoretical framework of the standard model and Brout-Englert-Higgs mechanism as well as a theoretical and experimental background of its search. This paper may attract interest of not only particle physicists but also a broader audience.Comment: LateX, 23 pages, 01 table, 9 figures. To appear in Commun. Phys. Version 2: Minor changes, two references adde

    A Complete Solver for Constraint Games

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    Game Theory studies situations in which multiple agents having conflicting objectives have to reach a collective decision. The question of a compact representation language for agents utility function is of crucial importance since the classical representation of a nn-players game is given by a nn-dimensional matrix of exponential size for each player. In this paper we use the framework of Constraint Games in which CSP are used to represent utilities. Constraint Programming --including global constraints-- allows to easily give a compact and elegant model to many useful games. Constraint Games come in two flavors: Constraint Satisfaction Games and Constraint Optimization Games, the first one using satisfaction to define boolean utilities. In addition to multimatrix games, it is also possible to model more complex games where hard constraints forbid certain situations. In this paper we study complete search techniques and show that our solver using the compact representation of Constraint Games is faster than the classical game solver Gambit by one to two orders of magnitude.Comment: 17 page

    One Village One Product (OVOP) in Japan to One Tambon One Product (OTOP) in Thailand: Lessons for Grass Root Development in Developing Countries

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    Following the 1997 Asian Financial Crisis, Thailand’s economy which did rely on external capital and resources suffered from an imbalanced economic growth. As a solution to the economic restructuring process, endogenous development concept proved to be an alternative development paradigm which prioritizes the community development, human empowerment in the transformation of local resources. Accordingly, One Tambon One Product (OTOP) was designed to unlock grass-root potentials by generating income through developing local products in a national, regional, and global scale. This initiative was first developed under the name of One Village One Product (OVOP) by local people in the poorest Oita Prefecture, Japan in 1961. The aim of the paper is to compare two development models of OVOP and OTOP. The comparative study draws useful lessons from the experience of OTOP for future applications of the OVOP model in developing economies. The paper finds that there are inevitable differences in terms of administration, finance management, human resource management, and marketing promotion management between bottom-up OVOP in Japan and top-down OTOP because of social diversity, political culture, and economic capability in Thailand. The paper contributes to provide a comparative study into models of sustainable development in the context of increasing gap between the urban and rural in globalization

    CHARACTERISTICS OF RECEIVING WATERS IN A SHRIMP AQUACULTURE AREA IN CAI NUOC, CA MAU

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    Unregulated shrimp aquaculture development has posed several negative impacts to the receiving waters of the coastal Cai Nuoc district, Mekong delta of Vietnam where most of the land area was converted to shrimp farms since 2000. Enhanced organic loadings and salinisation of surface water and sediment are the major physico-chemical impacts. Increasing levels of organic loadings and suspended solids were found in the receiving waters, mainly as a result of shrimp farm discharge and run-off. The salinization has been caused by the irrigation of saltwater to the interior fields for shrimp culture. The shrimp aquaculture practice has also caused a reduction in phytoplankton diversity and changes in the structures of zooplankton and zoobenthos community. The bacterial community in the receiving waters has also been enriched as a result of enhanced organic loadings. Shrimp aquaculture practices might deteriorate the quality of the receiving waters, which is used as input water for shrimp farms

    Description of Geocenamus vietnamensis sp. n. (Nematoda : Merliniidae) from Vietnam

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    A new species of the genus Geocenamus was isolated from soil and root samples from the rhizosphere of Casuarina equisetifolia (Casuarinaceae) in Quang Nam province, Vietnam. This species is characterized by a round-to-hexagonal labial disc, the presence of a labial region, which is continuous or slightly offset from the body with six sectors, lateral sectors of first labial annulus being smaller than the submedian sectors, the presence of six to seven labial annules; the absence of deirids; stylet length 24 to 28 mu m long, body length 776 to 979 mu m long; lateral field with six to eight lateral lines, without areolation at mid-body and with areolation in outer bands at the tail region and a pointed tail terminus. Geocenamus vietnamensis n. sp. most closely resembles G. boghiae in having a non-sclerotized head framework and lacking a bursa in the males. It can be clearly distinguished from all other species of the genus Geocenamus by these characteristics. The combination of morphology, morphometric features, and phylogenetic trees, based on D2-D3 of 28S and ITS rDNA sequences, showed that this new species can be clearly separated from all other sequenced species. This record is the first for Geocenamus in Vietnam

    In Vitro Culture Of Maize (Zea Mays L.) Inbred Line Sm5-4

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    Tissue culture of inbred line SM5-4 maize (Zea mays L.), maternal parent of Putra J- 58 (F1 hybrids) was established using maize zygotic embryo as explant. To obtain embryogenic callus from mature and immature zygotic embryos of inbred line SM5- 4, manipulations of media components such as carbon, nitrogen, proline, and casein hydrolysate, and culture conditions such as incubation temperature, light, were carried out. Immature embryos have the ability to form callus and embryogenic calli, which can result in plant regeneration. At tissue culture level, the study aims at establishing the best tissue culture system via somatic embryogenesis and to overcome plant regeneration problems by manipulating the sucrose concentration, hormone combination and concentration, culture age, the type of medium formulation used to grow callus, incubation temperature, light and media formulation. Sterilization technique of maize from mature and immature maize seeds of the inbred line SM5-4 was investigated. Mature seeds (50 days old) and immature seeds (14 days after pollination) were disinfected by washing in different concentrations of sodium hypochlorite (Clorox) for different duration. Disinfection in 50%(v/v) Clorox solution (2.27% sodium hypochlorite) for 20 minutes gave 90% of contaminationfree culture of mature seeds whereas 50%(v/v) Clorox solution (2.27% sodium hypochlorite) for 15 minutes gave 75% of contamination-free culture of immature seeds. Reduction in Clorox concentration of 20% (v/v) Clorox (1.05% sodium hypochlorite) for 20 minutes gave high percentage (67%) of contamination- free culture of immature seeds that remain viable. N6 basal medium was found to be the best medium in enhancing both callus induction and embryogenic calli formation. The highest callus induction frequency on N6 basal medium supplemented with 9 pM 2,4-D from immature zygotic embryos was 79.5%. Both plants growth regulators, 2,4-D, IAA and BAP, kinetin, were capable of switching on the induction of callus necessary for embryogenic totipotency. The combination of 2,4-D and kinetin were however more effective in producing callus induction in embryos culture of maize. The most effective method for producing friable, embryogenic callus was found for immature zygotic embryos. Maturation of somatic embryos was enhanced by transferring the embryogenic callus after 4 weeks to medium containing 6% sucrose and Img/L NAA. During the following 3-4 weeks, as the somatic embryos developed, the cultures were transferred to the regeneration medium (MSO). Approximately 80% of immature zygotic embryos produced embryogenic callus and then plantlets. Immature embryos of inbred line SM5-4 produced the highest percentage of callus and showed the highest number of plant regeneration compared to mature zygotic embryos

    Morphological and molecular characteristics of Pratylenchus haiduongensis sp. n., a new species of root-lesion nematodes associated with carrot in Vietnam

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    Pratylenchus haiduongensis sp. n. is described as associated with carrot (Daucus carota subsp. sativus (Hoffm.) Schubl. & G. Martens) in Hai Duong Province, Vietnam. P. haiduongensis sp. n. is characterized by the lip region with three annuli and slightly separated from the body. Stylet knobs are rounded (never indented anteriorly). The lateral field includes four incisures, bearing areolation at the pharynx region and tail region and occasionally appears in the vulval region. Sometimes the appearances of oblique broken striaes divide the lateral field into five or six incisures. The ovary is distinct with one row of oocytes. Spermatheca is oval in shape with round central cavity, without sperm or reduced in some specimens. The postvuval uterine sac is long surpassing the vulva body diameter by 2 to 2.5 times (PUS = 31 to 65 mm). High vulva position with V = 66 to 75%. The tail shape can be subhemispherical with a smooth, slightly indented, broadly smooth, or cleft terminus observed in some specimens. The matrix code of P. haiduongensis sp. n. is: A2, B1, C4, D(1,3), E1, F(5,6), G(1,2), H(1,4); I(1,2,3,4), J1, K(1,2) according to Castillo and Vovlas (2007). The LSU-D2D3 segment and the ITS-rDNA region of this species were amplified and sequenced. The morphological characters and molecular phylogenetic analyses confirmed that this is a new species of the genus Pratylenchus in Vietnam
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