Decreasing behavior of the depth functions of edge ideals

Let $I$ be the edge ideal of a connected non-bipartite graph and $R$ the base polynomial ring. Then $\operatorname{depth} R/I \ge 1$ and $\operatorname{depth} R/I^t = 0$ for $t \gg 1$. We give combinatorial conditions for $\operatorname{depth} R/I^t = 1$ for some $t$ in between and show that the depth function is non-increasing thereafter. Especially, the depth function quickly decreases to 0 after reaching 1. We show that if $\operatorname{depth} R/I = 1$ then $\operatorname{depth} R/I^2 = 0$ and if $\operatorname{depth} R/I^2 = 1$ then $\operatorname{depth} R/I^5 = 0$. Other similar results suggest that if $\operatorname{depth} R/I^t = 1$ then $\operatorname{depth} R/I^{t+3} = 0$. This a surprising phenomenon because the depth of a power can determine a smaller depth of another power. Furthermore, we are able to give a simple combinatorial criterion for $\operatorname{depth} R/I^{(t)} = 1$ for $t \gg 1$ and show that the condition $\operatorname{depth} R/I^{(t)} = 1$ is persistent, where $I^{(t)}$ denotes the $t$-th symbolic powers of $I$.Comment: 15 pages, 3 figure

DIESEL OIL UTILIZING-BIOSURACTANT PRODUCING BACTERIAL ISOLATE AND CHARACTERISTICS OF PRODUCED BIOSURFACTANTS TOWARD BIOREMEDIATION APPLICATION

Joint Research on Environmental Science and Technology for the Eart

Study on conformational structure of tamarind seed polysaccharide and its sulfated derivative by light scattering method

The aim of this study was to study the conformational changing when sulfated groups were introduced to the molecular chain of native tamarind seed polysaccharide (TSP). Light Scattering (LS) method was used to determine conformation of TSP and its sulfated derivative TSPS. The results indicated that both TSP and TSPS have a highly branched and more sphere-like molecule; however, after sulfation, the TSPS became more branched structure than native polysaccharide. Keywords. Tamarind seed polysaccharide, conformation, light scattering

Evaluation of Asaoka and Hyperbolic Methods for Settlement Prediction of Vacuum Preloading Combined with Prefabricated Vertical Drains in Soft Ground Treatment

This study evaluated the use of the Asaoka and hyperbolic methods to estimate the ultimate settlement of soft ground treated by vacuum preloading combined with prefabricated vertical drains. For this aim, a large-scale physical laboratory model was constructed. The model was a reinforced-tempered glass box containing a soil mass with dimensions of 2.0 × 1.0 × 1.2 m (length × width × depth). Physical models of this scale for the same purpose are rare in the literature. The soil was taken from a typical coastal region in Dinh Vu Hai Phong, Vietnam. The surface settlement near and between the two drains was measured right after the vacuum preloading started. Important properties of the soil were tested to evaluate the effectiveness of the treatment method. The measured settlement was used in the Asaoka and hyperbolic methods to predict the potential ultimate settlement. The results showed the superiority of the vacuum consolidation approach in improving fundamental engineering properties of soft soil. Furthermore, the ultimate settlement predicted by both methods showed a good agreement with the measured value, proving that the Asaoka and hyperbolic methods are suitable for the estimation of the ultimate settlement of soft soil treated with vacuum consolidation

Management and monitoring of air and water pollution by using GIS technology: Research article

The need for a green clean living environment is increasing today, with the boom of the socioeconomic development, educational level. However, the environmental pollution becomes an alerted global issue due to the large amount of wastes discharged making this need to be not easily met at the moment. Greenhouse gas emission mainly from energy, transport and agricultural land use is causing climate change because of their long atmospheric lifetime and trapping the heat in the atmosphere. Harmful effects and damages caused by environment pollution and climate change are unpredictable. It was reported that every year millions of people die because of fine particles when exposing to air pollution and other millions die from water-born diseases. Management and monitoring of air and water pollution by using GIS technology is an effective method. The measured data can be obtained continuously, quickly and accurately at stations in any regions even with complex terrain. This helps reduce the required number of employees, manage automatically and continuously a large number of data.Ngày nay nhu cầu về một môi trường sống xanh, sạch đang gia tăng, với sự bùng nổ của phát triển kinh tế - xã hội và trình độ dân trí. Tuy nhiên, ô nhiễm môi trường đang trở thành một vấn đề cảnh báo toàn cầu do số lượng lớn các chất thải được xả ra môi trường làm cho nhu cầu này không dễ dàng được đáp ứng tại thời điểm này. Phát thải khí nhà kính chủ yếu là từ sử dụng năng lượng, giao thông vận tải và đất nông nghiệp đang gây ra biến đổi khí hậu vì thời gian tồn tại của cúng dài và giữ nhiệt trong khí quyển. Các ảnh hưởng xấu và thiệt hại gây ra bởi ô nhiễm môi trường và biến đổi khí hậu là không thể đoán trước. Thông tin báo cáo chỉ ra rằng mỗi năm có hàng triệu người chết vì hít các hạt bụi mịn khi tiếp xúc với ô nhiễm không khí; và hàng triệu người khác chết vì bệnh do nước sinh ra. Quản lý và giám sát ô nhiễm không khí và nước bằng cách sử dụng công nghệ GIS là một phương pháp hiệu quả. Các dữ liệu đo có thể được lấy liên tục, nhanh chóng và chính xác tại các trạm ở bất kể khu vực nào, ngay cả nơi có địa hình phức tạp. Điều này giúp làm giảm số lượng lao động cần thiết, quản lý tự động và liên tục một số lượng lớn dữ liệu

Ownership Concentration and Accounting Conservatism: The Moderating Role of Board Independence

The purpose of this study is to examine the moderating effect of board independence on the relationship between ownership concentration and accounting conservatism. Using fixed-effect regressions for a sample of 165 Vietnamese listed companies from 2007 to 2017, the results revealed that the proportion of outstanding shares owned by the largest shareholder is negatively associated with accounting conservatism and board independence plays a moderating role in this relationship. Our results are robust after applying alternative measures of the largest ownership and correcting for potential endogeneity using fixed-effects regression with instrumental variables. Overall, our evidence shows that firms with concentrated ownership should keep a high non-executive ratio to maintain accounting conservatism. In other words, increasing the number of non-executive directors on boards in firms with a substantial proportion of shares held by the largest shareholder is likely to strengthen the information environment, giving financial reporting more credibility.JEL Classification: G30; G32. Doi: 10.28991/ESJ-2023-07-01-07 Full Text: PD

LƯỢNG GIÁ KINH TẾ GIÁ TRỊ DU LỊCH TỪ CÁC HỆ SINH THÁI BIỂN VÙNG ĐẢO BẠCH LONG VĨ, HẢI PHÒNG

Bach Long Vi island is an offshore district in the centre of the Gulf of Tonkin in Vietnam and administratively belongs to Hai Phong city. The island surrounded by abundant marine ecosystems with high biodiversity is one of 16 marine protected areas approved by the Prime Minister of Vietnam on 26/5/2010 according to the Decision No.742/QD-TTg. Currently, in addition to the main service of economic activities as fishery logistics, Bach Long Vi island still remains the wild features with beautiful scenery, fresh air and the diversity of marine species that are suitable for the development of eco-tourism and resorts. Although tourism at present is not developed yet, its potentials are promising. Deploying zone travel cost method (ZTCM), tourism potentials based on ecosystem services of Bach Long Vi island were estimated at 5.4 billion VND (Vietnamese currency). The value can be much higher if the infrastructure of the island is improved and the island is accessible more easily. Tourism potential valuation and identification of the advantages of the island strongly support tourism planning in the future.Đảo Bạch Long Vĩ là đảo xa bờ nhất của Việt Nam trong vịnh Bắc Bộ và về mặt hành chính là một huyện đảo trực thuộc thành phố Hải Phòng. Đảo có hệ sinh thái biển bao quanh khá phong phú, đa dạng sinh học cao, là một trong số 16 khu bảo tồn thiên nhiên biển Việt Nam đã được Thủ tướng chính phủ phê duyệt lựa chọn vào ngày 26/5/2010 theo Quyết định số 742/QĐ-TTg. Hiện nay, ngoài hoạt động kinh tế dịch vụ chính là hậu cần nghề cá, huyện đảo Bạch Long Vĩ vẫn giữ nguyên được nét hoang sơ với cảnh quan đẹp, không khí trong lành và sự đa dạng của các loài hải sản thích hợp với phát triển du lịch sinh thái, nghỉ dưỡng. Mặc dù hiện tại du lịch chưa phát triển ở vùng đảo, tuy nhiên tiềm năng du lịch rất lớn. Bằng phương pháp tính chi phí du lịch theo vùng (ZTCM), giá trị tiềm năng du lịch trên nền tảng các dịch vụ hệ sinh thái của đảo Bạch Long Vĩ được ước tính là 5,4 tỷ đồng/năm. Giá trị này còn cao hơn nhiều nếu hạ tầng cơ sở của đảo và khả năng đi lại thuận tiện. Ước tính giá trị tiềm năng du lịch và xác định cụ thể những yếu tố thuận lợi giúp khu vực này phát triển tốt du lịch trong tương lai

Biosecurity practices in small-scale pig farms in Hung Yen and Nghe An, Vietnam

With pork representing more than 70% of meat consumption in Vietnam pig production is growing fast and plays an important role in the livestock production. Especially smallholder farms contribute substantial to the pork supply (approximately 80 %) because of consumer preferences, subsistence and commercial purposes. Despite of this considerable market share the overwhelming majority of smallholder pig farms lack of technologies, biosecurity and control measures in terms of diseases, hygiene and environment conditions. As being part of a wider research on improving smallholder pig value chains in Vietnam a longitudinal survey was conducted with the objectives to assess biosecurity practices and related farm management which will be used to identify suitable options for improved disease control. The survey was carried between March and December 2014 in the Hung Yen and Nghe An provinces of Vietnam. Thirty farms were selected randomly in each provinces as a sub-sample from a larger sampling frame (N=416) and visited in fortnightly intervals. On farm data by using a checklist and observations included information on farm management, biosecurity measures, working and feed storage conditions as well as diseases events. In general diseases control measures were found insufficient. The majority of farmers allowed visitors to access the farm without any restrictions (69.7%) throughout the entire observation period. Disinfection mattresses were installed only in 42.7% of visits, and even applied, often not maintained. The use of protective clothes and boots by workers was the exception (81.2%). Pre-weaning piglets were usually not provided with litter (88.9%) and/or heat sources (74.1%), the latter being a particular constraint during the cold season. From an animal welfare perspective it was notable that only approximately half of farms provided permanent water access to their pigs (48%). Poor management was also reported for feed handling and storage with clear signs of rodents or pests in feed (47.9%) and visible signs of moisture (49.4%). Observed gaps in farm management will be addressed in the upcoming intervention phase by developing and testing of packages guided by feasibility, cost benefit and farmers compliance

EFFECTS OF SALT STRESS ON PLANT GROWTH AND BIOMASS ALLOCATION IN SOME WETLAND GRASS SPECIES IN THE MEKONG DELTA

Salt stress causes serious damage to many cellular and physiological processes that leads to yield reduction. The study induced salt stress using Hoagland solution added NaCl to evaluate its effects on plant growth and biomass allocation of some wetland grass species in order to identify salt-tolerant species for replacing and/or supplementing rice/grass in rice-shrimp model and salt-affected area in the Mekong Delta. The study also seeks to evaluate the response of leaf chlorophyll (SPAD unit) and proline content in salt-treated plants to varying application of salinity. Typha orientalis, Lepironia articulata, Eleocharis dulcis and Scirpus littoralis were studied in hydroponics condition with four levels of NaCl of 5, 10, 15, 20‰ and the control treatment (without adding NaCl). The experiment was arranged in a completely randomized design with 3 replications. The salt-treated plants showed visually clear responses of inhibited growth under salt stress condition compared to the control plants. Among the four studied species, T. orientalis produced the highest dry shoot biomass (15.5 g DW/plant), while E. dulcis had the lowest value (2.8 g DW/plant). However, only T. orientalis showed significantly decreased in biomass as salinity increased with 9.3 and 4.6 times lower of fresh and dry biomass in plants grown at the salinity level of 20‰ compared to those grown in the control treatment. The other three plant species did not affect by salinity levels. The results indicated that S. littoralis, L. articulata and E. dulcis could tolerate at high salinity of 20‰ (eq. to the EC value in the nutrient solution of 38.0 dS/m) and could be potential candidate to grow in the rice-shrimp model or in the salt-affected soils.