Explore the vast range of titles available.

Coastal shorelines are naturally dynamic, shifting in response to coastal geomorphological processes. Globally, land use change associated with coastal urban development and growing human population pressures is accelerating coastal shoreline change. In southern Vietnam, coastal erosion currently is posing considerable risks to shoreline land use and coastal inhabitants. The aim of this paper is to quantify historical shoreline changes along the Hon Dat coast between 1995 and 2009, and to document the relationships between coastal mangrove composition, width and density, and rates of shoreline change. The generalized linear mixed-effects models were used to quantify the major biophysical and land-use factors influencing shoreline change rates. Most significant drivers of the rates of change are cutting of mangroves, the dominant mangrove genus, changes in adjacent shoreline land use, changes of shoreline land cover, and width of fringing mangroves. We suggest that a possible and inexpensive strategy for robust mangrove shoreline defense is direct mangrove planting to promote mangrove density with the presence of breakwater structures. In the shorter term, construction of coastal barriers such as fence-structured melaleuca poles in combination with mangrove restoration schemes could help retain coastal sediments and increase the elevation of the accretion zone, thereby helping to stabilize eroding fringe shorelines. It also is recommended that implementation of a system of payments for mangrove ecosystem services and the stronger regulation of mangrove cutting and unsustainable land-use change to strengthen the effectiveness of mangrove conservation programs and coastal land-use management.

Mangrove soil is crucial for maintaining the health and nutrient balance of coastal ecosystems. It often serves as the final sink for commercial, aquaculture, and agricultural contaminants. This necessitates developing and understanding precise insights into mangrove health and sustainability through tailor-made evaluation indices. Currently, there are few studies regarding the assessment of mangrove ecosystem sustainability. The Thai Binh Mangrove is the third-largest province in terms of mangrove coverage in northern Vietnam. This mangrove has not undergone a direct assessment of soil quality using ground-level data. Therefore, this study focuses on evaluating the current state of the Thai Binh Mangrove in Vietnam, identifying key factors contributing to its degradation. Soil samples were collected from 38 stations across the mangrove and analyzed for pH, heavy metals, and nutrients over two years, from 2022 to 2023. The mangrove soil quality is assessed using Principal Component Analysis (PCA) and Cluster Analysis (CA). The Pollution Load Index (PLI) is used to characterize soil pollution, and it ranges from 0.29 to 1.09. Additionally, the Ecological Risk Index (ERI) is used to assess the ecological impact of soil pollution, revealing that the area falls within the low-risk category. The study also proposes measures like aquaculture, ecotourism, and increased awareness and education regarding the sustainability of mangroves and soil quality. The study underscores the significance of international cooperation, treaties, and legislative reform in assisting decision-makers with sustainable mangrove management.

Urbanization and associated forest conversions have given rise to a continuum of native (forest fragments) and modified (artificial grasslands and perennial ecosystems) land-use types. However, little is known about how these shifts affect soil and fine-root compartments that are critical to a functioning carbon and nutrient circulation system. In this study, soil physicochemical properties, fine-root mass, and vertical distribution patterns were investigated in four representative urban land-use types: grassland (ZJ), perennial agroecosystem (MP), broadleaf deciduous forest patch (QA), and coniferous evergreen forest patch (PD). We quantified the fine-root mass in the upper 30 cm vertical profile (0–30 cm) and at every 5 cm depth across three diameter classes (<2 mm, 2–5 mm, and <5 mm). Soil physicochemical properties, except for phosphorus, nitrogen, ammonium nitrogen, and sodium cations, varied significantly across land-use types. The total root biomass (<5 mm) decreased in the order of QA (700.3 g m−2) > PD (487.2 g m−2) > ZJ (440.1 g m−2) > MP (98.3 g m−2). The fine-root mass of ZJ and MP was correlated with soil nutrients, which was attributed to intensive management operations, while the fine-root mass of QA and PD had a significant relationship with soil organic matter due to the high inputs from forest litter. Very fine roots (<2 mm) presented a distinct decremental pattern with depth for all land-use types, except for MP. Very fine roots populated the topmost 5 cm layer in ZJ, QA, and PD at 52.1%, 49.4%, and 39.4%, respectively. Maintaining a woody fine-root system benefits urban landscapes by promoting soil stabilization, improving ground infiltration rates, and increasing carbon sequestration capacity. Our findings underscore the importance of profiling fine-root mass when assessing urban expansion effects on terrestrial ecosystems.

Chukrasia tabularis A. Juss produces a valuable timber but plantations are susceptible to attack by the shoot-tip borer Hypsipyla robusta Moore. An integrated pest management (IPM) approach is desirable to limit the extent of damage. Therefore, this study was undertaken to evaluate the deployment of IPM measures in plantations in Vietnam. Data on tree damage and the biology of H. robusta were gathered in 4 provinces over one year and used to build an investigation schedule. Two preliminary IPM trials were then established in which Bacillus thuringiensis and Metarhizium anisopliae were applied to the foliage when the damage incidence (P%) was in the range 5–10%; and insecticides (Carbaryl, Carbosulfan) were applied when the P% exceeded 10%. In addition, larvae and pupae were removed manually over time. In the first trial, the combination of manual and biological control methods reduced the damage index (DI) of trees from 4 tolerant families by 82% compared to the untreated control plots. In the second trial using standard planting stock, application of insecticides was required to reduce the DI by 83%. Six extended IPM trials were undertaken using the same IPM protocols and these reduced the DI to the same extent as in the preliminary trials. Over an 18-month period, the deployment of IPM increased height growth by 19–22% and diameter growth by 38–41% compared to the controls. These findings highlight the value of planting improved seed and the benefit of adopting an IPM approach to manage the shoot-tip borer.

According to field surveys as well as data recorded in text documents, it can be said that Vietnam has historically been hit by a tsunami. However, we still do not have enough information to accurately determine the destructive power of these tsunamis against the coastal line of Vietnam. On the other hand, in the South China Sea, there are four potential earthquakes that could lead to tsunamis affecting coastal line of Vietnam. Using models, tsunami simulations as well as computing algorithms, experts say that tsunamis will appear and attack coastal line of Vietnam when there are submarine earthquakes with magnitude of larger than 7 at the fault along Central Asia shelf with an earthquake with magnitude of greater than 8 at the Manila Trench. If an earthquake of magnitude 8 occurs in the south of Hainan, the tsunami impacting coastal line of Vietnam will be greater than 2 m. If an earthquake of magnitude 8 occurs in Manila, the tsunami from Da Nang city to Quang Ngai will reach 4 m. From there we can see that the risk of tsunami occurring and attacking the coastal cities of Vietnam is there, although the probability is not high.

Chukrasia tabularis A. Juss produces a valuable timber but plantations are susceptible to attack by the shoot-tip borer Hypsipyla robusta Moore. An integrated pest management (IPM) approach is desirable to limit the extent of damage. Therefore, this study was undertaken to evaluate the deployment of IPM measures in plantations in Vietnam. Data on tree damage and the biology of H. robusta were gathered in 4 provinces over one year and used to build an investigation schedule. Two preliminary IPM trials were then established in which Bacillus thuringiensis and Metarhizium anisopliae were applied to the foliage when the damage incidence (P%) was in the range 5-10%; and insecticides (Carbaryl, Carbosulfan) were applied when the P% exceeded 10%. In addition, larvae and pupae were removed manually over time. In the first trial, the combination of manual and biological control methods reduced the damage index (DI) of trees from 4 tolerant families by 82% compared to the untreated control plots. In the second trial using standard planting stock, application of insecticides was required to reduce the DI by 83%. Six extended IPM trials were undertaken using the same IPM protocols and these reduced the DI to the same extent as in the preliminary trials. Over an 18-month period, the deployment of IPM increased height growth by 19-22% and diameter growth by 38-41% compared to the controls. These findings highlight the value of planting improved seed and the benefit of adopting an IPM approach to manage the shoot-tip borer. Key words: insect pest, integrated pest management, mahogany, plantation

Background The incidence of gastric cancer differs among countries in Asia, and it has been suggested that virulence factors associated with Helicobacter pylori are partly responsible. The aim of this study was to investigate several genetic factors regarded as virulence or molecular epidemiologic markers in H. pylori isolates from Vietnamese subjects. Results The cagA , vacA and cag right-end junction genotypes of 103 H. pylori strains from Vietnam (54 from Hanoi and 49 from Ho Chi Minh) were determined by PCR and sequencing. Three types of deletion in the region located upstream of the cagA Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region were identified: the 39-bp deletion type, the 18-bp deletion type, and the no-deletion type. The majority of strains studied (77%; 80/103) had the 18-bp deletion irrespective of geographical location in the country or clinical outcome. All of the 39-bp and 18-bp deletion-type strains possessed the East Asian type cagA repeat region. The type II cag right-end junction genotype was predominant (84%). The vacA m1 genotype was significantly more common in strains isolated in Hanoi, where the incidence of gastric cancer is higher, than in strains from Ho Chi Minh. Conclusion Pre-EPIYA-region typing of the cagA gene could provide a new genetic marker of H. pylori genomic diversity. Our data support the hypothesis that vacA m1 is closely associated with gastric carcinogenesis.

The present study evaluated the effectiveness of the synergy of XK9 and galactooligosaccharides (GOS) in improving growth performance, nonspecific immunity, and protection of striped catfish ( ). Seven feed regimens were tested in striped catfish fingerlings, including commercial pellets supplemented with preparations S , S , and S containing XK9 at 10 CFU/mL, 108 CFU/mL, and 109 CFU/mL, respectively; G5 containing 5% GOS; S7G , S , and S including 5% GOS and XK9 at different doses of 10 CFU/mL, 108 CFU/mL, and 109 CFU/mL, respectively. After 3 months of treatment with different dietary regimens, weight gain, specific growth rate, weight gain rate, and feed conversion ratio were greatly improved in fish fed diets containing S , S , and S (P<0.05). Nonspecific immune parameters, including total white blood cell, phagocytic activity, and phagocytic index, increased consistently in fish that were fed diets containing synbiotics S and S9G (P<0.05). Lysozyme and complement activity increased substantially in fish that were fed diets supplemented with S (P<0.05). The protective effect of XK9 and GOS on striped catfish was evaluated after 15 days of challenge with . The results achieved show that the cumulative mortality rate sharply decreased in fish fed a diet containing the synbiotic S down 2.17 times compared to the control group; pathogen density was lowest in tanks of fish that were fed regimens containing S , S , and S (P<0.05). The results suggest that synbiotics, including XK9 and GOS, have the potential to be applied in sustainable farming for the striped catfish industry.