Management des ressources humaines individualisé, axé sur les profils motivationnels : un outil d'augmentation du profit individuel et organisationnel.

Si pour l’individu, la motivation au travail n’est pas une nécessité absolue, de nombreuses études montrent qu’il y a un lien de cause à effet entre la motivation des salariés et la performance de l’entreprise. A l’issue de l’analyse des résultats de nos enquêtes auprès de cadres français et vietnamiens, nous présentons des recommandations pour la GRH dans sa mission d’assurer un double développement organisationnel et personnel des cadres. Elles portent sur les trois points suivants: –1) compréhension de la motivation des cadres et de l’influence des variables personnelles sur leur motivation; –2) mise en évidence des structures motivationnelles de cadres; –3) compréhension des profils motivationnels en vue d’un management individualisé des cadres. Enfin, les nouvelles pistes de recherche seront identifiées.Ressources humaines; Motivation au travail; Motivation des cadres;

The effects of avian influenza on rural poultry farmers’ livelihood

The objective of this research was to investigate how HPAI (highly pathogenic avian influenza) shocks and threats affected livelihood assets of poultry farmers. The policies helping poultry farmers to mitigate HPAI at national and local levels and what livelihood strategies did the poultry farmers have in order to accommodate threats and outcomes by avian influenza in Yen Son and Tan Binh communes - Tam Diep town – Ninh Binh province? The study combined both qualitative and quantitative approaches in collecting data and information. The findings of this study find that poultry production can be considered as important for the livelihoods of rural people in Yen Son and Tan Binh communes. However, avian influenza broke out repeatedly in these two communes in four years of 2004, 2005, 2007 and early 2008. This affected both directly and indirectly, both negatively and positively the poultry farmers’ livelihood. Under the negative effects of avian influenza on poultry farmers’ livelihood, the government at national as well as local levels has had the culling programme to reduce the spread of avian influenza. Coupled with the culling programme is a compensation policy for the poultry farmers. According to the ideas of the farmers who kept ducks, the compensation levels of Ninh Binh province in 2004, 2005, and 2007 were too low as compared to the market value, but they agree with the compensation level in 2008. Nevertheless, the farmers who kept the local chicken show that the compensation levels of province in four years were not suitable for their local chicken. In addition, the poultry farmers did not get the compensation money of Ninh Binh province until after 6 months as from their poultry were culled. Despite that, the poultry farmers still reported sick birds to veterinary staffs. Besides, vaccination support policy and training courses have been implemented to help the poultry farmers in these two communes mitigate avian influenza in the long term. It appears that the compensation and vaccination supporting policies can be considered as helping poultry farmers in avian influenza mitigation, but the training courses have not contributed much. To cope with avian influenza shock in the short term, the poultry farmers get the assistance of both non- family and family network and came with temporary off- farm and non- farm employments such as working for Dong Giao farm, selling vegetable or construction work to earn a income for their living. To respond to avain influenza threats in the future, they have the risk management strategies decisions depending on household specific characteristics for example, many households stop poultry production and change to other activities. Nevertheless, the majority of households restarts poultry production, but makes technical changes and combines poultry production with other activities

Depth of powers of edge ideals of Cohen-Macaulay trees

Let $I$ be the edge ideal of a Cohen-Macaulay tree of dimension $d$ over a polynomial ring $S = \mathrm{k}[x_1,\ldots,x_{d},y_1,\ldots,y_d]$. We prove that for all $t \ge 1$, $$\operatorname{depth} (S/I^t) = \operatorname{max} \{d -t + 1, 1 \}.$

Investigating the elements influencing the psychological issues of reform school students

Reformatory students are those whose deviant behaviors and habits prevent them from receiving education under normal educational conditions. These students frequently lead a careless, undisciplined lifestyle, being unwilling to work and learn eager to play and demanding. Therefore, when they are admitted to reformatories with severe study and lifestyle requirements, they have great psychological difficulty adjusting to their new environment. Students’ psychological issues in adapting to reformatory learning and living regimes are difficult and psychological deficits make it challenging for students to adapt to reformatory learning and living conditions. In Vietnam, 665 students from reformatory schools were polled to determine the causes of psychological issues. According to the findings, a variety of elements contribute to students’ psychological difficulties. Individual student conditions such as health, awareness, attitudes and actions as well as inappropriate habits, living without goals or aspirations, etc. are on the subjective side of the equation. On the objective side are the students’ conditions, family, education and psychological obstacles brought on by less-than-ideal circumstances which will make it more difficult for community students to adapt. Both the new school and society must pay more attention to reformatory students in order to establish the conditions necessary for successful integration into the new school and ultimate readmission into society for these students

Co-treatment of organic fractions of urban waste for energy recovery: a case study from Hanoi city, Vietnam

The authors have quantified material and energy flows in two options of co-treatment of organic fractions of wastes by composting, and by anaerobic digestion. The results shown thermophilic anaerobic co-digestion of septic tank sludge, sewage sludge and organic municipal solid waste has provided the biogas yield of 19.6 m3 per ton of mixed waste, equal to 114 kWh of heat and power. The calculation for the case of Long Bien district, Hanoi city has shown anaerobic co-digestion of waste fractions could generate 111,220 kWh of heat and power per day, helping the waste treatment complex to be selfsufficient in terms of energy. Besides, 32.2 MWh/day of surplus energy could be sold to the grid. This option also reduced emission of greenhouse gases versus composting. The study can be used as basis for cost-benefit analyses in selection of appropriate urban waste management options aiming at efficient utilization of engineering infrastructure systems, waste treatment and resource recovery

Estimation of errors in determination of main parameters of earthquake hypocenter, recorded by the national seismic network of Vietnam

In this paper the authors present the error estimation in determining main parameters of earthquake hypocenter based on solving the system of linear equations, expressing the relationship between earthquake coordinates and the coordinates of the seismic stations. The results of the error estimation in determining the epicenter coordinates and the focus depth of the earthquakes recorded by the system of 30 seismic stations in Vietnam are presented, interpreted and compared with the results of the previous studies.The results show that the operation of the seismic network of Vietnam is not really optimal, particularly when determining the epicenter coordinates and the focus depth of the earthquakes in the East Vietnam Sea region.The national seismic network of Vietnam allows determination of the epicenter coordinates and the focal depth of earthquakes for most of the Vietnam territory with the errors ∆h ≤ 20 km, ∆φ ≤ 4 km, ∆ ≤ 5 km. The errors of the determination of the epicenter coordinates and the focal depth of the earthquakes are increasing to the south and southwest areas of the territory of Vietnam and reach the maximum in these areas. Particularly, errors of the determination of the epicenter coordinates (∆φ, ∆λ) and the focal depth (∆h) of earthquakes increase very rapidly toward the East Sea of Vietnam and reach the maximum in the region between the longitudes of 116-118°E.The Vietnam seismic network allows determining the epicenter coordinates and the focal depth of earthquakes in the Northern Vietnam with the smaller errors than in Central and Southern Vietnam, and this fact proves that the distribution of seismic network in Northern Vietnam is more optimal than the station networks in the Central and Southern Vietnam. Therefore, in order to improve the effectiveness of the Vietnam seismic network, more seismic stations need to be added to the Central and Southern Vietnam.References Aranovich Z.I., 1980. On the method of selecting the optimal positions of seismic stations in the local network. //Methodologies and assessment results of the effectiveness of the regional seismic network. Tbilisi: Mesnhiereba, 150-157 (in Russian).Aranovich Z.I., Akhalbedasvili А.М., Gosadze О.D. et al., 1977. The methodologies of evaluating the effectiveness of regional seismic network, in case of the Caucasus region.//The issues of optimization and automation of seismic observations. Tbilisi: Mesnhiereba, 27-57 (in Russian). Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La-Bac Yen fault zone. J. Sci. of the Earth, 35, 53-49.Burmin V. Yu.,  1976. The task of experimental planning and the estimation of the system of linear algebraic equations.//The USSR Academy of Sciences Publishing House. Cybernetics, 2, 195-200. Burmin V. Yu., 1986. The optimal distribution of seismic stations when recording near earthquakes.//The USSR Academy of Sciences Publishing House. Geophysics. Moscow, 5, 34-42 (in Russian).Burmin V. Yu., Akhmechiev V.M., 1994. The errors in determining parameters of near earthquake hypocenter and the effectiveness of seismic network.//Journal of Volcanology and Seismology. Moscow, 2, 109-128 (in Russian).Burmin V. Yu., Ngo TL., Kondorskaia N.V. and Akhmechiev V.M., 1992. The geometric analysis of existing seismic network in the Northern Vietnam.//The news from Russian Academy of Sciences. Journal of Geophysics. Moscow, 6, 123-128 (iIn Russian).Burmin V. Yu., Ngo T.L., Tran V.P., 2009. Estimation of efficiency of seismic stations modern network and design of an optimal one on the territory of Vietnam.// Journal “Seismic Instruments”, 45(1), 27-35.Burmin V. Yu., Nguyen VP., 2001. Planning to optimum regional network of the seismological observations for South- East Asia.//Journal “Volcanology and Seismology”, 1, 68-75.Iosif T. and Iosif S., 1974. Optimization of seismic stations distribution in Romania.//Studii si cercetari de geofisica, 12, 51-88.Iosif T., Skoko D. and Sato Y., 1972. Optimum distribution of seismic stations in Romania.//Bull. Int. seism. Earthq. Eng, 9, 121p.Kijko A., 1975. On optimal extensions of regional networks of seismic stations - Publs. Inst. Geophys. Pol. Acad. Sci., 96, 57-119.Kijko A., 1978. Method of the optimal planning of regional seismic networks.//Polish Academy of Sci. publication of the inst. Of geoph. A-7 (119). Panctwowe wydawnictwo naukowe. Warszawa; Lodz, 63p.Kijko A., 1980. Optimum seismic networks in the Ostrova coal basin.//Czechoslovakia. Acta montana UGG CSAV. Praha, 55, 73-95.Marshall A.W., Olkin I., 1965. Norms and inequalities for condition numbers.//Pacific J. Math, 15, 241-247.Marshall A.W., Olkin I., 1969. Norms and inequalities for condition numbers.//Linear Algebra and Application, 2(2), 167-172.Marshall A.W., Olkin I., 1973. Norms and inequalities for condition numbers.//Linear Algebra and Application, 3(7), 191-300.Ngo TL., 1990. Kinetic and dynamic parameters of earthquake hypocenter in the Northern Vietnam. The Candidate of Sciences Thesis on Mathematics-Physics, Speciality Geophysics. Institute of Geophysics, the USSR Academy of Sciences. Moscow, 133p (in Russian).Ngo T.L., 1999. The characteristics of seismicity and the main features of earthquake hypocenter in the Southeast Asia from the viewpoint of clarifying the new tectonic structures. The Doctor of Science Thesis on Mathematics-Physics, Speciality Geophysics. Institute of Geophysics, the USSR Academy of Sciences. Moscow, 342p (in Russian).Ngo T.L., 2005. The algorithm for improvement of velocity model of Earth’s crust and hodographs of travel times of seismic waves in the territory of Vietnam. J. Sci. of the Earth, 27(1), 23-26.Ngo T.L., 2005. The analysis of the seismic data for accounting hodographs of travel times of P-wave. J. Sci. of the Earth, 27, 374-377.Ngo T.L., Tran V.P., Vu T.H., Le T.T., 2014. The establishment of velocity model and hodographs of travel times of seismic waves in the Earth’s crust in the Northern, Central and Southern regions of Vietnam. Journal of Geology, Hanoi, Series A, 341-345, 355-365.Nguyen Quy Hy, et al., 1979. Optimal addition of seismic network in the Vietnam territory by the method of seismic experimental planning.//The research results of “Earth Sciences” 1977-1978. Series Geophysics. Vietnam Academy of Science and Technology. Hanoi, 9-31 (in Vietnamese).Nguyen Van Hung., Hoang Quang Vinh, Nguyen Van Huong, 2016. Tectono-structural system and geodynamic features of Northwest Vietnam in the late Cenozoic period. Vietnam J. Earth Sci., 38(1), 38-45. Doi: 10.15625/0866-7187/38/1/8408.Sato Y., 1965. Optimum distribution of seismic observation points.//Zisin J. Seism. Soc. Japan, 18(1), 9-14.Sato Y., Skoko D., 1965. Optimum distribution of seismic observation points II.//Bull. Earthquake. Res. Inst., 43(3), 451-458.Sato Y., Ochi I., 1967. Accuracy of the determination of earthquake source parameters in and around Japan.//Bull. Earthq. Res. Inst., 45(1), 1-17.Savarenski E.F., Shafronov V.V., Peskov A.B. et al., 1979. Optimal planning of seismic stations from the viewpoint of minimizing error in the epicenter determination.//The USSR Academy of Sciences Publishing House, 8, 64-71 (in Russian).Skoko D., Kotake Y., Sato Y., 1968. Optimum distribution of seismic observation points. V//Bull. Earthquake. Res. Inst., 46(4), 821-840.Skoko D., Sato Y., Ochi I., Dutta T.K., 1966. Accuracy of the determination of earthquake source parameters as determined by Monte Carlo method: Observation on Indian Network.//Bull. Earthquake. Res. Inst., 44(3), 893-900.  

EFFECT OF FISH SCALE COLLAGEN ON SOME CHARACTERISTICS AND DRUG RELEASE OF CARRAGEENAN/COLLAGEN/ALLOPURINOL FILM

ABSTRACT - QMFS2019Collagen from fish is attracting a lot of attention thanks to its high absorbance ability, biocompatibility as well as non-religious obstruction and cheap sources. It could be applied in many fields, for example: food, cosmetic, or biomedicine. Using of collagen also helps to reduce the environment pollution from fish scale waste in fish processing. In this study, collagen extracted from Vietnamese fresh-water tilapia fish scales was used in combination with carrageenan for the improvement of drug release control. The influence of fish scale collagen content on morphology, thermal behavior and drug release from carrageenan/collagen/allopurinol composite film was evaluated by methods such as field emission scanning electron microscopy (FESEM), differential scanning calorimetric (DSC) and ultraviolet-visible spectroscopy (UV-Vis). From the DSC data, FESEM analysis and drug release of carrageenan/collagen/allopurinol composite films, the most suitable collagen in composite film is 5 wt.%

Algorithm and program for earthquake prediction based on the geological, geophysical, geomorphological and seismic data

By applying an improved  method of the Earth's crust classification, we develop an algorithm and build an earthquake prediction program using a combination of geological, geophysical, geomorphological and seismic data.This program includes a system of multiple windows with different functions, which can divide fault zones into the different segments by the maximum magnitude values Mmax. Using the constructed program, we carried out an earthquake prediction test for the Northwest Vietnam by a combination of geological, geophysical, geomorphological and seismic data. According to the received results, zoning maps of maximum earthquake prediction for the researched region has been established. The results show that the   areas, capable of generating earthquakes with Mmax = 6.5 - 6.8  are primarily concentrated along some major fault zones such as Lai Chau-Dien Bien, Son La, Song Ma, Song Da, Tuan Giao or near the intersection of these fault zones. The received results show a good accordance with the actual seismotectonic characteristics of the researched region.References Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La - Bac Yen fault zone. Journal of Sciences of the Earth 35, 53-49.Cao Dinh Trieu, 1999. Probable approach for long-term earthquake prediction in Vietnam based on the regulation of epicentral distribution. Journal of Geology, Series A (251), 14-21, Hanoi (in Vietnamese).Cao Dinh Trieu, Nguyen Huu Tuyen, Thai Anh Tuan, 2006. The correlation between the structure of the Earth’s crust and seismic activities in the Northwest region of Vietnam”. Journal of Sciences of the Earth, 28, 155-164, Hanoi (in Vietnamese).Cao Dinh Trieu, Ngo Thi Lu, Cao Xuan Bach et al., 2007. Prediction of maximum earthquake occurrence in Vietnam on the basis of crustal characteristics”. Proceedings of the 5th Vietnam’s Scientific Conference on Geophysics, 159-171, Science and Technics Publishing House, Hanoi (in Vietnamese).Dang Thanh Hai, Nguyen Duc Vinh, Cao Dinh Trieu, 2002. Long-term earthquake prediction in Lai Chau-Dien Bien region on the basis of time - magnitude model. Journal of Science and Technology, 40(4), 45-53, Hanoi (in Vietnamese).Dang Thanh Hai, 2003. Study on deep structures of the Earth’s crust and seismotectonic zoning in Northern Vietnam. Physics Ph.D. Thesis, 170p, Hanoi (in Vietnamese).Grishin A.P., 2001. The statistical model for predicting the occurrence time and magnitude of the earthquake”. Journal of Volcanology and Seismology (4), 60-65, Russian Academy of Sciences, Moscow. (in Russian).Grishin A.P., N.V. Kondoskaya, L.E. Levin, L.N. Solodinov, A.L. Petrov, O.M. Petrov, 2001. “Experiment of statistical prediction in Kaspi region (occurrence time, epicenter coordinate and magnitude value of the earthquake). Geophysics in the 21th century, The 3rd Collection of Reading Materials on Geophysics, Scientific World, 149-156.Gubin I.E., 1950. The method of seismotectonic zoning. The projects of The Geophysical Center, Russian Academy of Sciences, 13.Gumbel E.J., 1958. Statistics of Extremes”. Columbia Univ. Press.Gutenberg B. and G.F. Richter, 1954. Seismicity of the Earth and associated phenomena. Princeton Univ. Press.Ngo Thi Lu, Tran Viet Phuong, 2012. About the approach to building algorithms and processes to predict earthquakes by statistical model. Journal of Sciences of the Earth, 34(4), 535-541.Ngo Thi Lu, Tran Viet Phuong, 2013. Building a new algorithm of the program for separation of forshock and aftershock groups from earthquake catalog to ensure the independence of the events. Journal of Marine Science and Technology. 3A(13), 79-85.Ngo Thi Lu (Project manager), 2011. Assessment of the seismic potential in Vietnam based on a combination of geological, geophysical and seismic data”. The international scientific cooperation between Vietnam Academy of Science and Technology and Russian Academy of Sciences under the state-level protocol (2008-2010), Final Report, 163p, Hanoi (in Vietnamese).Ngo Thi Lu (Project manager), 2013. Establishment of experimental program for short-term earthquake prediction based on the statistical model combined with tectonophysics in Vietnam and adjacent regions. The independent project of Vietnam Academy of Science and Technology, Code VAST.DL.09/11-12, 125p, Hanoi (in Vietnamese).Nguyen Hong Phuong, 1991. Probabilistic assessment of earthquake hazard in Vietnam based on seismotectonic regionalization. Tecronophysics, 198, 81-93.Nguyen Hong Phuong, 1997. Evaluation of the maximum earthquake for seismic source zones in Vietnam by a combination of probability methods. The scientific works on geology and marine geophysics (3), 48-65, Science and Technics Publishing House, Hanoi (in Vietnamese).Nguyen Hong Phuong, 2001. Probabilistic Seismic Hazard Assessment Along the Southeastern Coast of Vietnam, Natural Hazards 24, 53-74.Nguyen Hong Phuong, Pham The Truyen, 2014. Probabilistic Seismic Hazard Assessment for the South Central Vietnam. Vietnam Journal of Earth Sciences 36, 451-461.Nguyen Dinh Xuyen (Project manager), Nguyen Ngoc Thuy et al., 1996. Database of earthquake mitigation measures in Vietnam. The final report of state-level independent project, Code KT-DL 92-07, 3 volumes, Institute of Geophysics, Hanoi (in Vietnamese).Nguyen Dinh Xuyen, 2002. Earthquake and earthquake hazard level. Internal document, Institute of Geophysics, Hanoi (in Vietnamese).Nguyen Dinh Xuyen, Pham Dinh Nguyen, Pham Quang Hung, Nguyen Anh Duong, 2003. Experiment of long-term earthquake prediction based on the mechanism of foreshock activities. Journal of Sciences of the Earth, 25(3), 193-200, Hanoi (in Vietnamese).Phan Trong Trinh, Ngo Van Liem, Nguyen Van Huong, Hoang Quang Vinh, Bui Van Thom, Bui Thi Thao, Mai Thanh Tan, Nguyen Hoang, 2012. Late Quaternary tectonics and seismotectonics along the Red River fault zone, North Vietnam. Earth-Science Reviews 114(3), 224-235.Phan Trong Trinh , Hoang Quang Vinh, Nguyen Van Huong, Ngo Van Liem, 2013. Active fault segmentation and seismic hazard in Hoa-Binh reservoir, Vietnam. Cent. Eur. J. Geosci. 5(2), 223-235.Pham Van Thuc and Kijko, A., 1985. Estimation of maximum magnitude and seismic hazard in Southeast Asia and Vietnam. Acta Geophys. Pol., XXX111 (4), 377-387.Pham Van Thuc, 2007. Seismology and earthquake in Vietnam. The monographs on natural resources and environment in Vietnam, Publishing House for Science and Technology, Vietnam Academy of Science and Technology, 378p (in Vietnamese).Reisner G.I., L.I. Ioganson, M.G. Reisner, Iu.E. Baranov, 1993. Characteristic classification of the Earth’s crust and the modern geological process. Publishing House of Russian Academy of Sciences, Moscow, 210p (in Russian).Reisner G.I., L.I. Ioganson, 1996. The Extraregional Seismotectonic Method for the Assessment of Seismic Potential. Natural Hazards 14, 3-10 (Kluwer Academic Publishers, printed in the Netherlands).Tran Thi My Thanh, 2002. Assessment of seismic hazard in Vietnam and adjacent regions. Physics Ph.D. Thesis, 161 pages, Hanoi (in Vietnamese).Vu Thi Hoan, Ngo Thi Lu, M.V. Rodkin, Tran Viet Phuong, 2014. Application of the generalized extreme value distribution to study the seismicity of the Southeast Asian. Journal of Geology. Series A, 341-345. Hanoi. 

Models to Predict the Burden of Cardiovascular Disease Risk in a Rural Mountainous Region of Vietnam

Objective: To compare and identify the most appropriate model to predict cardiovascular disease (CVD) in a rural area in Northern Vietnam, using data on hypertension from the communities. Methods: A cross-sectional survey was conducted including all residents in selected communities, aged 34 to 65 years, during April to August 2012 in Thai Nguyen province. Data on age, sex, smoking status, blood pressure, and blood tests (glucose, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol) were collected to identify the prevalence of high blood pressure and to use as input variables for the models. We compared three models, Asian, Chinese Multiple-provincial Cohort Study (CMCS), and Framingham, to estimate cardiovascular risk in the coming years in this context and compare these models and outcomes. Results: The prevalence of high blood pressure in these communities was lower than reported nationally (12.3%). CVD risk differed greatly depending on the model applied: approximately 21% of the subjects according to the CMCS and Asian models, but 37% using the Framingham model, had more than 10% risk for CVD. In the group without current CVD, these numbers decreased to 9% using the CMCS and Asian models but increased to 28% according to the Framingham model. There were no significant differences between the Asian and CMCS models, but differences were highly significant when comparing Asian versus Framingham or CMCS versus Framingham model. Conclusions: The Asian and CMCS models provided similar results in predicting CVD risk in the Vietnamese population in Thai Nguyen. The Framingham model provided vastly different results. The suggestion may be that for the specific Vietnamese setting, the Asian and CMCS models provide most valid and reliable results; however, this has to be investigated in further analyses using real-life data for potential confirmation. © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR)

Phytoplankton community structure and water quality of Red River, Vietnam

This study aimed to describe the distribution and relative abundance of the phytoplankton obtained during the two seasons (rainy and dry seasons) from the Red river system. The water and phytoplankton samples were monthly collected during the year 2012 at four sampling stations along the Red River (Yen Bai, Vu Quang Hoa Binh,and Ha Noi) . Environmental variables (e.g. temperature, dissolved oxygen, pH, suspended solids, conductivity, TDS, NO3­-N, NH4­-N, PO4-P, Total Phosphorus; and DOC) and phytoplankton (e.g. cell density and relative abundant species) were analyzed. Six phytoplankton classes were identified with the Bacillariophyceae dominating in the phytoplankton community. A distinct seasonal variation in phytoplankton structure was observed with high cells density in dry season and low values in rainy season. PCA (Principal Component Analysis) showed that suspended solid factor that governed the temporal and spatial distribution of phytoplankton structure in the Red River system.Nghiên cứu này trình bày sự phân bố và độ phong phú tương đối của quần xã thực vật nổi vào mùa mưa và mùa khô trong hệ thống sông Hồng. Các mẫu nước và thực vật nổi được thu hàng tháng trong năm 2012 tại 4 điểm trên sông Hồng (Yên Bái, Vụ Quang, Hòa Bình và Hà Nội). Các thông số môi trường (nhiệt độ, lượng oxy hòa tan, pH, chất rắn lơ lửng, độ dẫn, TDS, NO3-N, NH4-N, PO4-P, T-P và DOC) và thực vật phù du (mật độ tế bào,độ phong phú tương đối ) đã được phân tích. Sáu lớph tảo được được xác định với tảo silíc chiếm ưu thế trong quần xã thực vật phù du. Sinh khối thực vật đạt giá trị cao vào mùa khô trong khi thấp vào mùa mưa. Phân tích hợp phần chính cho thấy yếu tố chất rắn lơ lửng đóng vai trò quan trọng việc xác định biến động thời gian và không gian cấu trúc quần xã thực vật nổi trong hệ thống sông Hồng