1,011 research outputs found
Changes of benthic macroinvertebrates in Thi Vai River and Cai Mep Estuaries under polluted conditions with industrial wastewater
The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries.
In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO), total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment.
The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 – 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 – 5.70 mg/L 0.024 – 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 – 2.746 individuals/m2 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results confirmed the advantage of using benthic macroinvertebrates and their indices for water quality assessment
CURRENT SITUATION OF IMPLEMENTATION AND SOLUTIONS TO IMPROVE THE LAW ON EMPLOYMENT OF FEMALE WORKERS IN VIETNAM
Vietnam is one of the countries with advanced female labor policies in the region as well as in the world. The Labor Code 2019 has 1 chapter with 11 separate articles stipulating policies for female employees such as employer responsibilities, regimes of maternity, sickness, employment, and gender equality. The Employment Law (2013) also details employment and policies related to employment for employees in general and female employees in particular. In recent years, the government and organizations have introduced many policies and measures to promote employment law enforcement for female workers in Viet Nam. However, the enforcement of employment laws for female workers in Vietnam still has many shortcomings such as the scarcity of resources and skills for education and training programs, the lack of pressure on enterprises that do not comply with policies to protect the rights of female workers. Therefore, it is necessary to improve the law to increase the ability to implement policies to support and enhance the rights of female workers. This article discusses the current situation of law enforcement and employment of female workers in Vietnam in a number of aspects and offers solutions to improve the law to promote the implementation of this content in practice. Article visualizations
Loop Numbers of Knots and Links
This thesis introduces a new quantity called loop number, and shows the conditions in which loop numbers become knot invariants. For a given knot diagram D, one can traverse the knot diagram and count the number of loops created by the traversal. The number of loops recorded depends on the starting point in the diagram D and on the traversal direction. Looking at the minimum or maximum number of loops over all starting points and directions, one can define two positive integers as loop numbers of the diagram D. In this thesis, the conditions under which these loop numbers become knot invariants are identified. In particular, the thesis answers the question when these numbers are invariant under flypes in the diagram D
Incidences between points and generalized spheres over finite fields and related problems
Let be a finite field of elements where is a large odd
prime power and , where , , and for all . A -sphere is a set of the form , where . We prove bounds on the number of incidences between a point set
and a -sphere set , denoted by
, as the following.
We prove this estimate by studying the spectra of directed graphs. We also
give a version of this estimate over finite rings where is
an odd integer. As a consequence of the above bounds, we give an estimate for
the pinned distance problem. In Sections and , we prove a bound on the
number of incidences between a random point set and a random -sphere set in
. We also study the finite field analogues of some
combinatorial geometry problems, namely, the number of generalized isosceles
triangles, and the existence of a large subset without repeated generalized
distances.Comment: to appear in Forum Mat
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