THE EFFECT OF Jussiaea octovalvis WEED DENSITIES ON THE GROWTH AND YIELD OF SEVERAL INTRODUCED VIETNAM RICE (Oryza sativa L.) VARIETIES

Rice is staple grain production play an important role for food security and the socioeconomic value of agriculture in South East Asia countries. Among the factors that have negative effects on rice, weed is the major one. Weed has the effects on growth and yield of rice by competition about light, water, nutrient, and space. Jussiaea octovalvis is a kind of weed in the field during time of rice growth to mature which effect on growth and yield of rice but not significant different based on this research. Treatments were arranged factorially in Randomized Block Design (RBD) with 2 factors, 20 treatments (4 varieties, 5 of weed densities) and 4 replications, each replication used 2 pots for each treatment. The data of the study showed that had different between the rate of growth and the yield of rice grain recovery product; especially at data of LL 58 DAP showed significant difference (P=0.017), which the highest rate is 59.13 cm of V2; for harvest data showed that V3 is the best result but it is also a sensitive one in condition of weed densities impaction more than the others varieties (D0V3=620.5; D4V3=438). In addition, the measurement of W1000 of rice grain (30.96 g) and Wt per pot (20.01 g) of D0V3 is weight more than the others treatment; within D4V4 was obtained lowest of W1000 (19.26 g) and the lowest of Wt is D1V1 (5.25 g). Beside that D2 and D4 are more effective on growth and yield of rice and it was non – significant. However, it is not interaction between weed densities and varieties rice

The Effect of Jussiaea Octovalvis Weed Densities on the Growth and Yield of Several Introduced Vietnam Rice (Oryza Sativa) Varieties

Rice is staple grain production that plays an important role in food security and the socio-economic value of agriculture in South East Asia countries. Among the factors that have negative effects on rice, weed is the major one. Its production constraint is directly seeded rice; besides, weed also affects rice growth and yield by competition about light, water, nutrient, space. Jussiaea octovalvis is a kind of weed in the field during rice growth to mature, which affects the growth and yield of rice but not significantly different based on this research. Treatments were arranged factorially in Randomized Block Design (RCBD) with two factors, 20 treatments (4 varieties, 5 of weed densities), and four replications, and each repetition used two pots for each treatment. As a result, the data showed the difference between the rate of growth and the yield of rice grain recovery products. Especially at data of LL 58 DAP showed significant difference (P=0.017), which the highest rate is 59.13 cm of V2; for harvest data showed that V3 is the best result, but it is also a sensitive one in the condition of weed densities impaction more than the others varieties (D0V3=620.5; D4V3=438). Besides, the measurement of W1000 of rice grain (30.96 g) and Wt per pot (20.01 g) of D0V3 is weight more than the other treatment; within D4V4 was obtained lowest of W1000 (19.26 g) and the lowest of Wt is D1V1 (5.25 g). Besides that, D2 and D4 are more effective on rice growth and yield, and it was non–significant. However, it is not the interaction between weed densities and varieties of rice

Blended Learning for Secondary Schools in Nam Dinh Province to Satisfy New Standards: The Current Situation and Proposed Models

We offered blended learning models for high schools in Nam Dinh province to satisfy Vietnam's new criteria. These models were based on general approaches to issues, theoretical research, and field research based on surveys and anket questionnaires conducted throughout the area. The results of a survey demonstrate that high school teachers in Nam Dinh have gained a fundamental grasp of blended learning and have, in practice, embraced both online and face-to-face instruction, particularly during the height of the Covid-19 outbreak. However, there was not a standard model for blended learning, therefore it was only used by a few persons. In other contexts, the concept of "blended learning" referred to what was effectively a face-to-face session that was broadcast over the Internet without the necessary adjustments being made to the content, methodology, or evaluation. As a result, we offer a number of different ways to blended learning for high schools in Nam Dinh in order to improve the quality of education provided throughout the province

Seed Health and Quality of Rice Seeds Produced by Farmer and Growing in Cho Moi District, An Giang Province, Vietnam

This study was conducted at Laboratory in An Giang University; the varieties examined were collected from farmer households in 2018 – they were varieties that the farmer stored for the next crop (Winter-Spring) from Autumn-Winter crop in Cho Moi district, An Giang Province, Vietnam. The research evaluated the quality of seed rice, which is provided and planted by the farmer. As a result, this study showed that almost all of the varieties of seed rice from farmer households indicated the ratio of filled-grain, the germination, and the determination of seedling healthy, which are lower than certified variation. Besides, the samples of seed rice from farmer household have more infected fungal; especially the samples with higher in a filled-grain ratio is less infected by fungi, there were 12 types of seed borne-fungi in rice varieties from the farmer (in Cho Moi district), included: Alternaria padwickii, Rhizoctonia solani, Aspergillus oryzae, Bipolaris oryzae, Cercospora janseana, Curvularia lunata, Fusarium moniliforme, Pyricularia oryzae, Sarocladium oryzae, Tilletia barclayana, Fusarium graminearum, and Ustilaginoidea viren

Effect of Molecular Charge Asymmetry on Even-to-odd Ratio of High-order Harmonic Generation

Recently, asymmetric molecules, such as HeH$_2^+$, CO, OCS, HCl, have been evolved much attention since its rich information in the high-order harmonic generation (HHG), whose ratio of adjacent even and odd harmonics characterizes the asymmetry of molecules. In this paper, we study the dependence of even-to-odd ratio on the asymmetric parameters, in particular, the nuclear-charge ratio, and the permanent dipole, by exploiting a simple but general model of asymmetric molecules $Z_1Z_2$ subjected to an intense laser pulse. The HHG is simulated by the numerical method of solving the time-dependent Schrödinger equation. We find out that this even-to-odd ratio strongly depends on the nuclear-charge ratio. In particular, the even-to-odd ratio reaches its maximum when the nuclear-charge ratio is about from 0.5 to 0.7. Besides, the dependence on the permanent dipole of the even-to-odd ratio has a non-trivial law. To explain, we calculate the analytical ratio of the transition dipole according to the emission of even and odd harmonics, and this ratio is well consistent with the even-to-odd ratio of the HHG

Evaluation of Pseudomonas stutzeri AM1 and Pseudomonas oleovorans ST1.1 isolated from shrimp pond sediments as probiotics for whiteleg shrimp, Litopenaeus vannamei culture

This study aimed to isolate the probiotic potential of nitrifying bacterial strains and to evaluate their effects on water quality and growth performance of the whiteleg shrimp, Litopenaeus vannamei. Based on an initial screening of 100 isolates identified from sediment samples, 12 strains could remove nitrogen compounds and two strains (Pseudomonas stutzeri AM1 and P. oleovorans ST1.1) showed highly efficient nitrogen removal ability. Within 96 h, total ammonia nitrogen (TAN) removal efficiency in the two strains was 28.0-31.6% and 21.5-24.9%, respectively. The water addition of 103 CFUmL-1 of P. stutzeri AM1 (T1) and P. oleovorans ST1.1 (T2) effectively reduced TAN, nitrite, nitrate, and total sulfide and increased the survival rate and biomass of shrimp. However, no significant differences were found between the control (T0) and treatment groups (T1 and T2) in the final weight, weight gain and specific growth rate of shrimp. Overall, P. stutzeri AM1 (T1) and P. oleovorans ST1.1 used as water supplements improved water quality and the survival rate of whiteleg shrimp

SEASONAL VARIATION OF PHYTOPLANKTON FUNCTIONAL GROUPS IN TUYEN LAM RESERVOIR, CENTRAL HIGHLANDS, VIETNAM

Seasonal changes in freshwater phytoplankton assemblages at Tuyen Lam Reservoir in the Central Highlands of Vietnam were classified into 23 functional groups based on physiological, morphological, and ecological characteristics. A total of 168 species were recorded during 10 surveys from 2015 to 2019 at 7 sampling sites, with Chlorophyta dominating in number of species. Phytoplankton abundance varied from 0.18×105 to 21.2×105 cells/L during the study period, mainly due to cyanobacteria. Seven of the 23 functional groups were considered to be dominant (relative density > 5%).  The dominant functional groups were groups M and G in the dry season and groups M, G, P, and E in the rainy season. Group M (Microcystis aeruginosa) was the most common in both seasons, while group P (Closterium, Staurastrum, Aulacoseira), group E (Dinobryon, Synura), and group G (Sphaerocystis, Eudorina) were more common in the rainy season. The Shannon diversity index (H¢) showed that phytoplankton communities were relatively diverse and that most of the study sites were lightly polluted. However, the ecological status has deteriorated at some locations due to the overgrowth of group M, leading to eutrophication in this reservoir. This study highlights the usefulness of functional groups in the study of seasonal changes in phytoplankton dynamics. Functional groups are applied for the first time at Tuyen Lam Reservoir and can be used to predict early-stage cyanobacterial blooms in future studies

Synthesize and characterization of artificial human bone developed by using nanocomposite

The combination of biopolymers with bioceramics plays vital role in development of artificial bone. Hydroxyapatite is extensively used as a material in prosthetic bone repair and replacement. In this paper synthesis of Hydroxyapatite- Polymethyl methacrylate – Zirconia (Hap-PMMA-ZrO2) composite by using powder metallurgy technique. The mechanical, morphological, In-vitro biocompatibility and tribological properties were characterized by universal testing machine, micro-vickers hardness tester, high resolution transmission electron microscope (HR-TEM), MTT assay and pin-on-disc setup. In-vitro cytotoxicity test on HeLa cell lines shows cell viability constant when doses concentration increases so material found non-toxic. Results show that micro Vickers hardness i.e. 520 approximately matches with natural human bone i.e. 400. Compressive strength is less as compared to human bone because of powder metallurgy route used for fabrication and is 74 MPa. Density of proposed composite artificial human bone i.e. 1.52 g/cc is less as compared to natural bone i.e. 2.90 g/cc. The Hap-PMMA-ZrO2 composite will be good biomaterials for bone repair and replacement wor

Risk Factors for Human Infection with Avian Influenza A H5N1, Vietnam, 2004

TOC Summary: Risk factors include direct or household contact with sick or dead poultry and absence of an indoor water source