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Copyright of Revista E-mercatoria is the property of Universidad Externado de Colombia, Departamento de Derecho Comercial and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El objetivo del artículo es analizar el concepto geométrico de radián a través de un fenómeno de transposición de conocimientos, el cual se investiga en diferentes obras elementales. Situamos el concepto en la configuración general de las producciones a lo largo del siglo XIX y nos interesamos por su uso en otras disciplinas. Las definiciones del concepto que aparecen en las obras de matemáticas, así como aquellas dedicadas a otras profesiones, son caracterizadas en el escrito desde la Teoría Antropológica de lo Didáctico por praxeologías matemáticas y praxeologías prácticas, en el sentido de Chevallard (2007) y Castela (2009), respectivamente.

At a time when diagnostic bacteriological testing procedures have become more complex and their associated costs are steadily increasing, the expected benefits of Total laboratory automation (TLA) cannot just be a simple transposition of the traditional manual procedures used to process clinical specimens. In contrast, automation should drive a fundamental change in the laboratory workflow and prompt users to reconsider all the approaches currently used in the diagnostic work-up including the accurate identification of pathogens and the antimicrobial susceptibility testing methods. This review describes the impact of TLA in the laboratory efficiency improvement, as well as a new fully automated solution for AST by disk diffusion testing, and summarizes the evidence that implementing these methods can impact clinical outcomes. [ABSTRACT FROM AUTHOR]

The situation was analyzed that has been established in the International System of Units (SI) as a result of adoption of the recommendation of the International Committee of Weights and Measures (CIPM) in 1980, which proposed to consider plane and solid angles as dimensionless derived quantities. It was shown that such decision was based on a misunderstanding of the mathematical formula, relating the arc length of a circle with its radius and corresponding central angle, as well as series expansions of trigonometric functions. As follows from the conducted analysis, the plane angle value does not depend on any of the SI quantities and should be treated as a base quantity, while its unit (radian) should be added to the population of base SI quantities. Therefore, the value of a solid angle becomes a derived quantity from a plane angle, and its unit (steradian) represents a coherent derived unit equal to a square radian. [ABSTRACT FROM AUTHOR]

Empirical studies of angle, angle measure, and radian angle measure have primarily focused on documenting students' and teachers' conceptions. Representations of angle measure have the potential to inform and build on these conceptions. To gain insight into the concept of radian angle measure from a curricular perspective, I investigated the representations of radian angle measure in eight widely used U.S. high school mathematics textbooks. The data for this study are the 20 figures and the 8 definitions of radian angle measure in the textbooks. Inductive content analysis was used to identify the frequency of observable characteristics in the representations. Textbook figures of radian angle measure most frequently focus on a one‐radian angle. Textbook figures also demonstrated radian angle measures in terms of π, in standard position, even when the Cartesian‐coordinate plane was not in the figure. The frequently used characteristics of radian representations could inadvertently reinforce a qualitative concept of angle, instead of fostering the quantitative attributes of radian angle measure. Moving forward, analyzing conceptions that are evoked by the frequently used representations of radian angle measure could build a link between evidence from this study and studies of learning. [ABSTRACT FROM AUTHOR]

We developed a novel wood recognition scheme based on wood surface spectral features that aimed to solve three problems. First was elimination of noise in some bands of wood spectral reflection curves. Second was improvement of wood feature selection based on analysis of wood spectral data. The wood spectral band is 350-2500 nm, a 2150D vector with a spectral sampling interval of 1 nm. We developed a feature selection procedure and a filtering procedure by solving the eigenvalues of the dispersion matrix. Third, we optimized the design for the indoor radian's mounting height. We used a genetic algorithm to solve the optimal radian's height so that the spectral reflection curves had the best classification information for wood species. Experiments on fivecommon wood species in northeast China showed overall recognition accuracy >95 % at optimal recognition velocity. [ABSTRACT FROM AUTHOR]

Copyright of Latin-American Journal of Physics Education is the property of Latin-American Physics Education Network and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a didactic-cognitive analysis of the unit of measurement that contains the argument of the trigonometrical functions at Mexican high school level. The didactic study demonstrates the phenomenon of dethematization in the radian, understood as the articulator concept, while the cognitive study offers elements for understanding the perceptions of teachers and students in relation to the angular units of trigonometric functions in school mathematics. In turn, the analysis of questionnaires applied to students and teachers indicate: 1) the improper use of calculators or other calculation systems and the tendency of teachers to focus on significant values; 2) that students do not perceive that the use of the calculator for trigonometric functions is mediated by at least two methods of calculation: the sexagesimal and the radian. [ABSTRACT FROM AUTHOR]

In this article is discussed a subject that generates controversies in the teaching of Physics: why the radian must be the correct unit for the measurements of plane angles. The answer is, in our opinion, in the concepts of Calculus, where the analytical notions are independent of the geometrical ones. [ABSTRACT FROM AUTHOR]

This study investigates pre-service mathematics teachers' concept images of radian and possible sources of such images. A multiple-case study was conducted for this study. Forty-two pre-service mathematics teachers completed a questionnaire, which aims to assess their understanding of radian. Six of them were selected for individual interviews on the basis of theoretical sampling. The data indicated that participants' concept images of radian were dominated by their concept images of degree. As the data in this study suggested, pre-service mathematics teachers were reluctant to accept trigonometric functions with the inputs of real numbers but rather they use value in degrees. More interestingly, they have two distinct images of π : π as an angle in radian and π as an irrational number. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to assess the agreement at the categorical level between the Vitek 2 system and the Colibri coupled to the Radian under real routine laboratory conditions. The 675 nonduplicate clinical strains included in this study (249 Enterobacterales isolates, 198 Pseudomonas aeruginosa, 107 Staphylococcus aureus, 78 coagulase-negative staphylococci, 38 Enterococcus faecalis, and 5 Enterococcus faecium) were isolated from nonconsecutive clinical samples referred to our laboratory between June and November 2020. In addition, 43 carbapenemase-producing Enterobacterales (CPE) formerly identified and stored in our laboratory were added to the panel, for a total of 718 strains. The overall categorical agreements between the two compared methods were 99.3% (4,350/4,380; 95% CI 99% to 99.5%); 98.6% (2,147/2,178; 95% CI 98.0% to 99.0%); 99.4% (1,839/1,850; 95% CI 98.9% to 99.7%); and 99.4% (342/344; 95% CI 97.9% to 99.8%) for Enterobacterales , P. aeruginosa, Staphylococcus spp., and Enterococcus spp., respectively. The most important cause of the very major errors encountered on the Vitek 2 for P. aeruginosa (62%, 13/21) was related to the presence of heteroresistant populations. Among the 43 CPE included in this study, one OXA-48-like, and one OXA-181-like were missed by the Vitek 2, even by rigorously applying the CPE screening cutoffs defined by EUCAST. The Colibri coupled to the Radian provide a fully automated solution for antimicrobial disk diffusion susceptibility testing with an accuracy that is equal to or better than that of the Vitek 2 system.

Equations for use with SI radian units have the option of showing the radian unit or not. When the radian is not shown, identical purely numerical values for angles (θ) are produced in each equation. This is the common procedure. When the radian is shown, not all the θ values can show a radian unit: some must remain as pure numbers. This procedure is used whenever convenient, usually for extra clarity. The article proposes that the constantly numerical values of θ be treated as trigonometrical ratios, currently recognised as the 'radian measure' or the 'circular measure' (abbreviated: circ) of angles, and replaced by 'circ θ'. This measure equals the length ratio (subtended arc/radius) for an angle θ at the circle centre. By this means the need for the dimensionless version of 'angle in radians' vanishes. In fact even dimensional angles in radians need not be used, because 'circ θ' allows any angle units to be used for θ. [ABSTRACT FROM AUTHOR]