31 research outputs found

    Role of Scientific Research for Lecturers of Current Universities

    Get PDF
    Scientific research for university lecturers plays an important role in training creative thinking ability, research capacity and scientific working style  for researchers. This contributes to clarifying some scientific issues and solving practical problems that arise in order to improve the quality of teaching. This article focuses on analyzing some issues about the role of scientific research for university lecturers today

    Detection of Luminescence Centers in Colloidal Cd0.3_{0.3}Zn0.7_{0.7}S Nanocrystals by Synchronous Luminescence Spectroscopy

    Get PDF
    With the advantages of selectivity, spectral resolution and reduction of interference on account of light scattering, synchronous luminescence spectroscopy (SLS) is successfully applied to analyze complex mixtures with overlapped emission and/or excitation spectra. In fact, it is difficult to clearly distinguish the contributions of various luminescence centers to low-energy band of semiconductor nanocrystals (NCs). Herein, we report the application of SLS method to detect luminescence centers in colloidal Cdsub0.3/subZnsub0.7/subS NCs. Their conventional luminescence and synchronous luminescence spectra were comparatively investigated. Differently from conventional luminescence spectrum, the emission peaks at 460 and 515 nm were found using SLS method. They are attributed to the emission transitions related to sulfur and zinc/cadmium vacancies. The obtained results are useful to clarify the nature of luminescence centers as well as relaxation mechanism in Cdsubx/subZnsub1-x/subS NCs

    Effects of ENSO on Autumn Rainfall in Central Vietnam

    Get PDF
    28 years (1980–2007) of station and gridded reanalysis data were used to investigate the effects of El Niño/Southern Oscillation (ENSO) on autumn rainfall in the Extended Central Vietnam (ECV) region. Results show that, under El Niño conditions, autumn rainfall in Central Vietnam is reduced by about 10 to 30%. This reduction seems to be caused by a weakening of the North East monsoon circulation, which appears to be linked to an anomalous anticyclonic vortex and a positive sea level pressure anomaly over the East Sea. In addition, the disappearance of a secondary moisture source over the southern region of the East Sea also favors the reduction in rainfall over this region. Conversely, during La Niña, the total autumn rainfall in the ECV region increases by about 9 to 19%. The strengthening of the North East monsoon, with a cyclonic wind anomaly over the East Sea, helps to increase the moisture supply to the area by about 10 to 20%, resulting in enhanced rainfall in the ECV. It is also found that the La Niña conditions do not only cause an increase in rainfall, but also change the temporal distribution of the monthly rainfall over the region, with more rainfall in the latter months of the year

    Validation of Mesocyclops (Copepoda) and community participation as an effective combination for Dengue control in Northern Vietnam

    Get PDF
    The “Programme Meso-Vietnam” was implemented in Vietnam from October 2007 to December 2010 to reduce dengue and dengue hemorrhagic fever incidence and to improve the quality of life in the four project communes. This dengue control project was based on biological control using Mesocyclops, a larvivorous micro-crustacean, as well as on the establishment of a strong community involvement to educate the population on dengue transmission and to reduce Aedes breeding by removal of containers. During three years, a network of collaborators was responsible for introducing Mesocyclops in all the containers defined as key breeding-sites, and regular activities such as community training workshops, school programmes, clean-up campaigns and health promotion through IEC programmess were performed. To make this programme sustainable, local leadership has been strengthened as well. The use of these larvivorous micro-crustaceans as a biological control strategy against dengue over the medium and long term, when combined with community participation and effective health promotion, demonstrated a significant reduction in dengue vector populations and dengue cases.  In Vietnam, this study reconfirms that there is an ecological alternative to systematic use of insecticides to control dengue vector population. (Abstract word count: 186)Le " Programme Meso-Vietnam " a été mis en œuvre au Vietnam entre octobre 2007 et décembre 2010. Ce programme vise à réduire l'incidence de la dengue et de la fièvre hémorragique de la dengue et à améliorer la qualité de vie dans les quatre communes sélectionnées pour le projet. Ce projet de lutte contre la dengue était basé sur un contrôle biologique assuré par des Mésocyclopes, micro-crustacés larvivores, et sur l'établissement d'une forte implication de la communauté pour éduquer la population sur la transmission de la dengue et pour réduire la reproduction des moustiques Aedes par élimination des conteneurs leur servant de site de ponte. Pendant trois ans, un réseau de collaborateurs a été chargé d'introduire des Mésocyclopes dans tous les conteneurs définis comme des sites de reproduction clés, et des activités régulières telles que des ateliers de formation communautaires, des programmes scolaires, des campagnes de nettoyage et des activités de promotion de la santé via les programmes IEC ont été mises en place. En outre, pour assurer la pérennité de ce programme, le leadership local a été renforcé. L'utilisation de ces micro-crustacés larvivores comme stratégie de contrôle biologique de la dengue à moyen et long terme, associée à une participation communautaire et à une promotion efficace de la santé, a permis d'aboutir à une réduction significative des populations vecteurs de la dengue et des cas de dengue. Au Vietnam, cette étude confirme une fois de plus qu'il existe une alternative écologique à l'utilisation systématique d'insecticides pour lutter contre les vecteurs de la dengue.El “Programa Meso-Vietnam” se implementó en Vietnam desde octubre de 2007 hasta diciembre de 2010 para reducir la incidencia del dengue y la fiebre hemorrágica del dengue y para mejorar la calidad de vida en los cuatro municipios del proyecto. Este proyecto de control del dengue se basaba en el control biológico usando Mesocyclops, un microcrustáceo larvívoro, así como en el establecimiento de una fuerte implicación comunitaria para educar a la población sobre la transmisión del dengue y para reducir la cría de Aedes mediante la eliminación de recipientes. Durante tres años, una red de colaboradores fue responsable de la introducción de Mesocyclops en todos los recipientes definidos como sitios clave para la cría, y se realizaron actividades regulares tales como talleres de formación comunitaria, programas escolares, campañas de limpieza y promoción de la salud a través de programas de IEC. Para hacer sostenible este programa, también se reforzó el liderazgo local. El uso de estos microcrustáceos larvívoros como estrategia de control biológico contra el dengue a medio y largo plazo demostró una reducción significativa de las poblaciones de vectores del dengue y los casos de dengue cuando se combinaba con la participación comunitaria y la promoción eficaz de la salud. En Vietnam, este estudio vuelve a confirmar que existe una alternativa ecológica al uso sistemático de insecticidas para controlar la población de vectores del dengue

    Enhanced drought tolerance of Arabica coffee (Coffea arabica L.) by grafting method

    Get PDF
    The objective of this study was to evaluate grafting method to improve the drought tolerance of Coffea arabica. Using C. arabica species as scions, and C. robusta as rootstock, the grafted plant was compared with the non-grafted plant (C. arabica) under water deficit condition. The result shown that growth parameters such as plant height, leaf length, and leaf width of the grafted coffee plants were higher than those of the non-grafted. The leaf area, fresh and dry weight of plants were highly reduced in non-grafted coffee plants. The leaf chlorophyll content (SPAD) and chlorophyll fluorescence (Fv/Fm) values of the grafted and non-grafted coffee plants decreased significantly with increasing duration under water deficit condition. The SPAD and Fv/Fm values of the two coffee types were also increased significantly with increasing duration after re-watering. Compared to the non-grafted plants, higher values of SPAD, Fv/Fm and relative water content in the leaf were observed in the grafted coffee plants. Moreover, lower values of relative ion leakage were observed in the grafted coffee plants after three days of water withholding and one month after re-watering. On the other hand, the grafted coffee plants showed enhanced drought tolerance by reducing the percentages of wilting plant under water deficit condition, and increasing the recovery percentages after re-watering

    TextANIMAR: Text-based 3D Animal Fine-Grained Retrieval

    Full text link
    3D object retrieval is an important yet challenging task, which has drawn more and more attention in recent years. While existing approaches have made strides in addressing this issue, they are often limited to restricted settings such as image and sketch queries, which are often unfriendly interactions for common users. In order to overcome these limitations, this paper presents a novel SHREC challenge track focusing on text-based fine-grained retrieval of 3D animal models. Unlike previous SHREC challenge tracks, the proposed task is considerably more challenging, requiring participants to develop innovative approaches to tackle the problem of text-based retrieval. Despite the increased difficulty, we believe that this task has the potential to drive useful applications in practice and facilitate more intuitive interactions with 3D objects. Five groups participated in our competition, submitting a total of 114 runs. While the results obtained in our competition are satisfactory, we note that the challenges presented by this task are far from being fully solved. As such, we provide insights into potential areas for future research and improvements. We believe that we can help push the boundaries of 3D object retrieval and facilitate more user-friendly interactions via vision-language technologies.Comment: arXiv admin note: text overlap with arXiv:2304.0573

    Wprowadzenie nowej aplikacji do symulacji i optymalizacji długoterminowego planowania produkcji w kamieniołomach wapienia

    No full text
    Long-term limestone quarry production planning is essential to maintain the supply to the cement plant. In which, quarry planners usually attempt to fulfil the complicated calculations, which ensure a consistent supply of raw materials to the cement plant while guaranteeing technical and operational parameters in mining. Traditionally, the calculations are done on a spreadsheet or by trial and error procedure resulting in high additive cost and an increase in product variability. Modern quarry management relies on block models and mathematical algorithms integrated into the software to optimize the long-term limestone quarry production planning. However, this method is potentially sensitive to geological uncertainty in block modelling, resulting in the deviation of the supply production of raw materials. The need for mining intelligently raw material is, therefore, crucial and an increasing issue in the cement industry. In this research, a new simulation and optimization software application called Quarrier is introduced, allowing quarry planners to address the conflicting requirements of long-term limestone quarry production planning while forecasting and mitigating the effects of geological uncertainty on the supply of raw materials for the cement plant. The benefits of this software are demonstrated through a limestone quarry in Vietnam.Długoterminowe planowanie produkcji w kamieniołomie wapienia ma zasadnicze znaczenie dla utrzymania dostaw do cementowni. W którym planiści kamieniołomów zazwyczaj starają się wykonywać skomplikowane obliczenia, które zapewniają stałe dostawy surowców do cementowni przy jednoczesnym zagwarantowaniu parametrów techniczno-eksploatacyjnych w górnictwie. Tradycyjnie obliczenia są wykonywane manualnie lub metodą prób, co skutkuje wysokimi kosztami dodatków i zwiększeniem zmienności produktu. Nowoczesne zarządzanie kamieniołomami opiera się na modelach blokowych i algorytmach matematycznych zintegrowanych z oprogramowaniem w celu optymalizacji długoterminowego planowania produkcji w kamieniołomie. Jednak metoda ta jest potencjalnie wrażliwa na niepewność geologiczną w modelowaniu bloków, co skutkuje odchyleniem w zakresie dostaw surowców do produkcji. Potrzeba inteligentnego wydobywania surowca jest zatem kluczowym i rosnącym problemem w przemyśle cementowym. W ramach tych badań wprowadzono nową aplikację do symulacji i optymalizacji o nazwie Quarrier, umożliwiającą planistom kamieniołomów sprostanie sprzecznym wymaganiom długoterminowego planowania produkcji kamieniołomu wapienia, jednocześnie prognozując i łagodząc skutki niepewności geologicznej na dostawy surowców do cementu. roślina. Korzyści płynące z tego oprogramowania są widoczne w kamieniołomie wapienia w Wietnamie

    North-directed Triassic nappes in Northeastern Vietnam (East Bac Bo)

    Get PDF
    International audienceA careful re-examination of the previous tectonic descriptions and the acquisition of new structural and kinematic data have been undertaken in northeastern Vietnam. The structure of the area consists of a system of slightly metamorphosed but ductilely deformed nappes, including recumbent folds, formed during the Triassic, prior to the unconformable deposition of the Upper Triassic terrigenous sediments. These results confirm the previous interpretation of " preyunnanaises nappes ", represented by Middle-Upper Paleozoic foliated limestone resting through a flat mylonitic contact over an intermediate " Song Mien unit " (Deprat, 1915), the latter made essentially of deformed Lower Triassic sedimentary and volcanic formations, which previously filled the Song Hien rift (Bourret, 1922). In the external part of the belt, the Triassic strata conformably overlie slightly deformed and unmetamorphosed Upper Paleozoic rocks, forming an autochthonous domain. Alternatively, the same Triassic succession can be seen resting tectonically through décollement zones, directly over the Middle Paleozoic marbles, to form a distinct but subsidiary allochthonous unit. Our data show that the Song Chay orthogneiss and its Lower Paleozoic sedimentary country rocks belong to the main nappe. They also demonstrate that this nappe was transported to the N-NE. A newly discovered ophiolitic mélange of supposed oceanic nature and Triassic age, lying along the Song Chay Fault, North of the Nui Con Voi, could hypothetically represent the rooted zone of the nappe. A Tertiary overprinting event, in particular accommodated by strike-slip movements, likely accounts for the present orocline of NE Vietnam

    Constellation of small quick-launch and self-deorbiting nano-satellites with AIS receivers for global ship traffic monitoring

    No full text
    Since December 2004 the International Maritime Organization's International Convention for the Safety of Life at Sea requires that Automatic Identification System (AIS) has to be implemented on all international voyaging ships with gross tonnage of 300 or more tons, and on all passenger ships regardless of size. This stems from the need of collision avoidance, search-and-rescue operations and other maritime purposes. Ground-based AIS receiving station usually cannot cover ships over the horizon, but with space-based AIS signal receivers, the global ship monitoring became possible, providing data service for maritime administrations, cargo liners, and even navies. Since 2007, a number micro-satellites and nano-satellites have been launched for technical demonstration in this respect. However, at present the space-based global AIS data service is not fully operational and international cooperation is limited. In this paper, a constellation of 3 self-deorbiting nano-satellites, with a mass equivalent to 3U cubesats, carrying AIS receivers is proposed to complement the existing systems. The feasible study presented here showed that this mission can be realized at very low cost, and quick-launched. Three other important features of the mission are: international cooperation, making a practical use of smaller nano-satellites and taking the responsibility for deorbiting the satellites at the end of mission. It is also the hope that this mission will become a milestone that marks the maturity of smaller nanosats, and give the "student satellite" projects around the world a new dimension for real application and sustainable business application

    Constellation of small quick-launch and self-deorbiting nano-satellites with AIS receivers for global ship traffic monitoring

    No full text
    Since December 2004 the International Maritime Organization's International Convention for the Safety of Life at Sea requires that Automatic Identification System (AIS) has to be implemented on all international voyaging ships with gross tonnage of 300 or more tons, and on all passenger ships regardless of size. This stems from the need of collision avoidance, search-and-rescue operations and other maritime purposes. Ground-based AIS receiving station usually cannot cover ships over the horizon, but with space-based AIS signal receivers, the global ship monitoring became possible, providing data service for maritime administrations, cargo liners, and even navies. Since 2007, a number micro-satellites and nano-satellites have been launched for technical demonstration in this respect. However, at present the space-based global AIS data service is not fully operational and international cooperation is limited. In this paper, a constellation of 3 self-deorbiting nano-satellites, with a mass equivalent to 3U cubesats, carrying AIS receivers is proposed to complement the existing systems. The feasible study presented here showed that this mission can be realized at very low cost, and quick-launched. Three other important features of the mission are: international cooperation, making a practical use of smaller nano-satellites and taking the responsibility for deorbiting the satellites at the end of mission. It is also the hope that this mission will become a milestone that marks the maturity of smaller nanosats, and give the "student satellite" projects around the world a new dimension for real application and sustainable business application
    corecore