BIOKEYS – AN INTEGRATED SYSTEM FOR WORKING WITH DATABASE AND POLYCLAVE IDENTIFICATION KEYS OF VARIOUS TAXONOMIC LEVELS

Unlike the other currently available identification software, BioKeys allows the users to create and use own polyclave identification keys of various taxonomic levels. The information of dedicated taxonomic level is stored in the head line of the key file so that BioKeys can understand and search in the right field of the database for the records of matched taxa. The results of database referencing or specimen identification will be displayed in a form of web page. Besides, utilities are available for creating and managing the database, for analyzing the polyclave identification key. An example of using BioKeys is provided with polyclave key of plant families of Magnoliophyta that has been created based on the punched-card system of Bertel Hansen and Knud Rahn (1969)

Study on some groups of microorganism during the forest rehabilitation process in Song Ma district, Son La province

The paper has made assessement on changes of some soil microorganism groups during the process of forest rehabilitation after shifting cultivation and after clear cutting in Song Ma district, Son La province. Sampling has been made in forest areas naturally regenerated for 4-6; 9-11; 14-16 and above 20 years after shifting cultivation and after clear cutting. The results have shown that the total aerobic bacteria, the total actinomycetes and the total microfungi have increased from the rehabilitation stage of 4-6 years (3.12×102; 1.23×103 and 8.05×102 CFU/g respectively in forest areas after shifting cultivation and 4.25×104; 2.32×103 and 7.32×103CFU/g respectively in forest areas after clear cutting) to the rehabilitation stage of ≥ 20 years (3.54×105; 2.23×104 and 2.51×104 CFU/g respectively in forest areas after shifting cultivation and 4.35×106; 2.72×105 and 5.46×105 CFU/g respectively in forest areas after clear cutting). The capacity in free nitrogen fixation, in cellulose decomposition, in phosphates decomposition, and in polysaccharide production of the aerobic bacteria, of actinomycetes, and of microfungi is lowest during the first forest rehabilitation stage (4-6 years), then it grows and reaches the highest value during the stage of≥20 years (5.60×103; 2.75×104; 2.10×103; 1.36×104 CFU/g respectively in forest areas after shifting cultivation and 5.24×103; 3.14×105; 4.27×104; 5.39×104 CFU/g respectively in forest areas after clear cutting)

Potential Use of Rice Husk Biochar and Compost to Improve P Availability and Reduce GHG Emissions in Acid Sulfate Soil

© 2020 by the authors. Acid sulfate soil (ASS) has major problems related to phosphorus deficiency and high potential for N2O emissions, as well as strong acidity. The objective of this study was to evaluate the effects of rice husk biochar and compost on P availability and greenhouse gas (GHG) emissions in ASS in in vitro incubation studies. An ASS was amended with two types of rice husk biochar (at rates of 0 g kg-1, 20 g kg-1, and 50 g kg-1, equivalent to 0 Mg ha-1, 20 Mg ha-1, and 50 Mg ha-1, assuming that bulk density was 1 g cm-3 and evenly applied for 10 cm in depth) and compost (at rates of 0 g kg-1, 10 g kg-1, and 20 g kg-1, equivalent to 0 Mg ha-1, 10 Mg ha-1, and 20 Mg ha-1) and incubated. Application of compost increased labile P by 100% and 200% at rates of 10 g kg-1 and 20 g kg-1, respectively. Both biochars showed an increase in NaHCO3-soluble inorganic P by 16% to 30%, decreases in NaOH-soluble inorganic P and NaHCO3-soluble organic P. N2O emissions were significantly decreased by 80% by a biochar with a higher surface area and higher NH4+ adsorption capacity at a rate of 50 g kg-1 as compared with those in un-amended soil. In contrast, compost amendment at a rate of 10 g kg-1 significantly increased N2O emission by 150%. These results suggest that in ASS, whilst compost is more effective in improving P availability, biochar is more effective in mitigating GHG emissions, emphasizing that fundamental characteristics of organic amendments influenced the outcomes in terms of desirable effects

The distribution of Meiofauna community related to salinity gradient in the Ham Luong estuary, Mekong river

Seventeen taxa of meiofauna community in the Ham Luong estuary were investigated and comprised. Free-living nematodes  were the most dominant and diverse group, presenting about 77% in the total of meiofauna density. Meiofauna density varied from 135.7 ± 33.5 inds/10 cm² to 1782.0 ± 199.5 inds/10 cm². The meiofauna density shows a decreasing trend from inland station to the brackish water station and it is increasing at mouth station. Significant differences in meiofauna density, diversity and Hill’s indices were found between stations. The ANOSIM showed significant differences between stations in meiofauna composition (overall R = 0.972, p = 0.1%). The SIMPER analysis clarifies that the average similarity within stations was quite high, changing from EHL3 (76.2%) to EHL1 (86.1%)

VỀ CHỈ SỐ CHÍNH QUY CASTELNUOVO-MUMFORD CỦA VÀNH TỌA ĐỘ CỦA TẬP n + 3 ĐIỂM BÉO KHÔNG SUY BIẾN TRONG KHÔNG GIAN XẠ ẢNH Pn

In this paper we calculate the Castelnuovo-Mumford regularity index of the coordinate ring of n + 3 a set of  non-degenerate fat points in Pn for almost all of cases.Trong bài báo này chúng tôi tính chỉ số chính quy Castelnuovo-Mumford của vành tọa độ của tập n + 3 điểm béo không suy biến trong Pn cho hầu hết các trường hợp của tập điểm

A Complete Method for Reconstructing an Elevation Surface of 3D Point Clouds

Reconstructing the surface of 3D point clouds is a reconstruction from a cloud of 3D points to a triangular mesh. This process approximates a discrete point cloud by a continuous/smooth surface depending on the input data and the applications of users. In this paper, we propose a complete method to reconstruct an elevation surface from 3D point clouds. The method consists of three steps. In the first step, we triangulate an elevation surface of 3D point cloud structured in a 3D grid. In the second step, we remove the outward triangles to deal with concave regions on the boundary of the triangular mesh. In the third step, we reconstruct this surface by filling the hole of triangular mesh. Our method could process very fast for triangulating the surface, preserve the topology and characteristic of the input surface after reconstruction

Impacts of fallow conditions, compost and silicate fertilizer on soil nematode community in salt–affected paddy rice fields in acid sulfate and alluvial soils in the Mekong Delta, Vietnam

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)Avoidance of intensive rice cultivation (IRC) and soil amendments are potential practices to enhance soil properties. There is only limited information on the effects of reduced IRC and its mixture with compost or silicate fertilizer (Si) on the soil nematode community in salt–affected soils. This study aimed to assess the shifts of soil nematode community by reducing a rice crop from triple rice system (RRR) to a double rice system and mixed with compost or Si in paddy fields in acid sulfate soil (ASS) and alluvial soil (AL) in the Mekong Delta, Vietnam. Field experiments were designed with four treatments in four replicates, including RRR and a proposed system of double–rice followed by a fallow (FRR) and with 3 Mg ha–1 crop−1 compost or 100 kg ha–1 crop−1 Si. Soils were collected at harvest after the 2 year experiment, reflecting the fifth and third consecutive rice crop in RRR and FRR system, respectively. Results showed that reduced IRC gave a significant reduction in abundance of plant–parasitic nematodes (PPN), dominated by Hirschmanniella and increased abundance bacterivorous nematodes when mixed to compost and silicate fertilizer in ASS. In addition, reduced IRC increased nematode biodiversity Hill’s indices and reduced herbivorous footprint in ASS. Proposed system having compost or Si had strongly increased in bacterivorous and omnivorous footprints. Particularly, reduced IRC mixture with Si increased abundance of Rhabdolaimus, Mesodorylaimus and Aquatides, metabolic footprints (structure footprint, bacterivorous, omnivorous and predator) and diversity Hill’s N1 index in ASS. Our results highlighted that reduced IRC was a beneficial practice for decreasing abundance of PPN in salt-affected soils and increasing abundance of FLN in ASS. IRC mixture with compost or Si had potential in structuring the nematode communities with increasing biodiversity, trophic structure, and metabolic footprintsPeer reviewedFinal Accepted Versio

The nematode community distribution in two estuaries of the Me Kong delta: Cung Hau and Ham Luong, South Vietnam

The highest numbers of nematodes with a percentage ranging from 76.4% in Cung Hau to 77% in Ham Luong estuaries. There were 92 genera (71 genera in Ham Luong and 62 genera in Cung Hau) of nematodes recorded in both estuaries. The mean nematode densities varied between 90 ± 31 - 1524 ± 269 ind.10 cm² and 105 ± 79 - 1120 ± 534 ind.10 cm² in Ham Luong and Cung Hau estuary, respectively. The nematode communities were mainly composed of Dichromadora, Daptonema, Oncholaimellus, Syringolaimus, Tripyloides, Parodontophora, Theristus and Halalaimus belonging to several dominant families, such as, Oncholaimidae, Xyalidae, Chromadoridae, Oxystominidae, Axonolaimidae and Sphaerolaimidae. In both estuaries, nematode density decreased from inland towards the mouth before they increased again at the mouth stations