Comparative Direct Analysis of Type Ia Supernova Spectra. V. Insights from A Larger Sample and Quantitative Subclassification

A comparative study of optical spectra of Type Ia supernovae (SNe Ia) is extended, in the light of new data. The discussion is framed in terms of the four groups defined in previous papers of this series: core normal (CN); broad line (BL); cool (CL); and shallow silicon (SS). Emerging features of the SN Ia spectroscopic diversity include evidence (1) that extreme CL SN 1991bg-likes are not a physically distinct subgroup and (2) for the existence of a substantial number of SN 1999aa-like SSs that are very similar to each other and distinguishable from CN even as late as three weeks after maximum light. SN 1999aa-likes may be relatively numerous, yet not a physically distinct subgroup. The efficacy of quantitative spectroscopic subclassification of SNe Ia based on the equivalent widths of absorption features near 5750 A and 6100 A near maximum light is discussed. The absolute magnitude dispersion of a small sample of CNs is no larger than the characteristic absolute magnitude uncertainty.Comment: 32 pages including 14 figures and 1 table, accepted by PAS

Asymptotic Equivalence of Triangular Differential Equations in Hilbert Spaces

In this article, we study conditions for the asymptotic equivalence of differential equations in Hilbert spaces. We also discuss the relationship between the properties of solutions of differential equations of triangular form and those of truncated differential equations.Вивчено умови асимптотичної еквівалентності диференціальних рівнянь у гільбертових просторах. Розглянуто також зв'язок між властивостями розв'язків диференціальних рівнянь трикутної форми та неповних диференціальних рівнянь

SELECTION OF PHYSICAL AND TECHNICAL ASSESSMENT TESTS FOR MALE BADMINTON PLAYERS AT CAN THO UNIVERSITY, VIETNAM

The performance of a badminton athlete relies heavily on his/her physical fitness and technical skills. This research aims to select appropriate tests for evaluating the physical fitness and technical proficiency of male badminton players representing the Can Tho University's team. The study employs standard research methodologies in sports science, including literature review, interviews, pedagogical assessment, and statistical analysis, to determine the reliability of the chosen tests. As a result, eight tests have been identified, comprising four assessing physical fitness and four assessing technical skills, including long jump (cm), 30-second abdominal crunch (times), 30-meter sprint (seconds), 1-minute rope jump (times), 20 lateral movements (seconds), back-and-forth blocking movements and shots in 1 minute (times), overhead shots in one minute (times), 40 jumps and shots (seconds).  Article visualizations

Leak testing of single-use biocontainer for bulk product storage and transport using flow measurement instrument

For some bulk drug products, the biopharmaceutical industry requires a complex transportation network for global shipping and storage under cold temperatures. With the growing demand for single-use technologies, there is need of an accurate method for assuring that single-use biocontainers remain integral throughout such transport and storage. Please click Additional Files below to see the full abstract

Effect of Encouragement-based Management Mechanism on Construction Firms’ Manpower Development: An Empirical Study from Vietnam

The construction industry should seek to enrich its workforces due to the increasing lack of trained and skilled employees. This study attempts to investigate the relationship between encouragement-based management mechanism (EMM) and manpower development (MD) in construction firms and examine the moderating effect of firm size on this relationship by conducting bivariate Pearson correlation and hierarchical multiple regression analyses to analyse empirical data collected from 79 construction firms in Vietnam. The results show that EMM positively affected MD, and this positive effect was stronger in small/medium-sized construction firms than in large firms. The findings could provide construction firms in Vietnam, as well as other developing countries, with a better understanding of the effect of EMM on MD. Hence, they could establish appropriate and wise encouragement-based strategies to enhance their manpower. This study could contribute to the extant literature on construction manpower development by providing empirical evidence of the EMM−MD relationship in the context of construction firms

Occurrence and dissipation of the antibiotics sulfamethoxazole, sulfadiazine, trimethoprim, and enrofloxacin in the Mekong Delta, Vietnam

The Mekong Delta in Vietnam has seen a rapid development and intensification of aquaculture in the last decades, with a corresponding widespread use of antibiotics. This study provides information on current antibiotic use in freshwater aquaculture, as well as on resulting antibiotic concentrations in the aquatic environment of the Mekong Delta. Two major production steps, fish hatcheries and mature fish cultivation, were surveyed (50 fish farm interviews) for antibiotic use. Different water sources, including surface water, groundwater and piped water (164 water samples) were systematically screened for antibiotic residues. To better understand antibiotic fate under tropical conditions, the dissipation behavior of selected antibiotics in the aquatic environment was investigated for the first time in mesocosm experiments. None of the investigated antibiotics were detected in groundwater and piped water samples. Surface water, which is still often used for drinking and domestic purposes by local populations, contained median concentrations of 21 ng L-1 sulfamethoxazole (SMX), 4 ng L-1 sulfadiazine (SDZ), 17 ng L-1 trimethoprim (TRIM), and 12 ng L-1 enrofloxacin (ENRO). These concentrations were lower than the predicted no effect concentrations (PNECs) and minimum inhibitory concentrations (MICs), suggesting limited antibiotic-related risk to aquatic ecosystems in the monitored systems. The dissipation half-lives of the studied antibiotics ranged from <1 to 44 days, depending on the availability of sunlight and sediment. Among the studied antibiotics TRIM was the most persistent in water systems. TRIM was not susceptible to photodegradation, while the dissipation of ENRO and SDZ was influenced by photolysis. The recorded dissipation models gave good predictions of the occurrence and concentrations of TRIM, ENRO and SDZ in surface water. In summary, the currently measured concentrations of the investigated antibiotics are unlikely to cause immediate risks to the aquatic environment, yet the persistence of these antibiotics is of concern and might lead to chronic exposure of aquatic organisms as well as humans

A STUDY ON THE DIFFICULTIES IN WRITING ARGUMENTATIVE ESSAYS OF ENGLISH-MAJORED SOPHOMORES AT TAY DO UNIVERSITY, VIETNAM

The research entitled “A study on the difficulties in writing argumentative essays of English-majored sophomores at Tay Do University” was conducted with the purpose of pointing out some common difficulties of sophomores in writing argumentative essays. The participants of this study were 90 English-majored sophomores of course 13, and two teachers who teach English language at Tay Do University. In this study process, questionnaire and interview were used as two instruments to collect the data. The results of the research would show that English majored sophomores met difficulties in term of linguistic competence (vocabulary, grammar and coherence), organization and development of an argumentative essay, and the lack of critical thinking. Article visualizations

A SURVEY ON COMMON ERRORS IN STUDYING SPEAKING SKILL OF ENGLISH-MAJORED FRESHMEN AT TAY DO UNIVERSITY, VIETNAM

Speaking is regarded as the most important aspect of communication skills, and it contributes to the success of language learners in their studies and careers, as well as the success of teachers in their teaching process. However, English-majored students, especially English-majored freshmen, usually face some errors in speaking English. Consequently, this research, entitled "A Survey on Common Errors in Studying Speaking Skills of English-majored Freshmen at Tay Do University" was conducted to figure out some common problems in speaking English that these English-majored students have encountered. The participants of this research were 80 students from two classes, English 15A and English 15B, at Tay Do University. The main research instrument for collecting the data was a questionnaire. The findings of this research pointed out the participants’ errors in speaking skills problems (pronunciation, grammar tense, pronunciation, mother tongue, vocabulary) and psychological problems (anxiety of error, lack of motivation, shyness, lack of confidence). The results showed that the students had errors in their speaking skills. Thanks to the results, some useful solutions were proposed for English-majored students.  Article visualizations

Automated Synthesis of Architecture of Avionic Systems

The Architecture Synthesis Tool (AST) is software that automatically synthesizes software and hardware architectures of avionic systems. The AST is expected to be most helpful during initial formulation of an avionic-system design, when system requirements change frequently and manual modification of architecture is time-consuming and susceptible to error. The AST comprises two parts: (1) an architecture generator, which utilizes a genetic algorithm to create a multitude of architectures; and (2) a functionality evaluator, which analyzes the architectures for viability, rejecting most of the non-viable ones. The functionality evaluator generates and uses a viability tree a hierarchy representing functions and components that perform the functions such that the system as a whole performs system-level functions representing the requirements for the system as specified by a user. Architectures that survive the functionality evaluator are further evaluated by the selection process of the genetic algorithm. Architectures found to be most promising to satisfy the user s requirements and to perform optimally are selected as parents to the next generation of architectures. The foregoing process is iterated as many times as the user desires. The final output is one or a few viable architectures that satisfy the user s requirements