1,724,940 research outputs found
Direct measurement of the speed of sound using a microphone and a speaker
Full text link[EN] We present a simple and accurate experiment to obtain the speed of sound in air using a conventional speaker and a microphone connected to a computer. A free open source digital audio editor and recording computer software application allows determination of the timeofflight of the wave for different
distances, from which the speed of sound is calculated. The result is in very good agreement with the reported value in the literature.The authors would like to thank the Institute of Education Sciences, Universitat Politecnica de Valencia (Spain), for the support of the Teaching ` Innovation Groups, MoMa and e-MACAFI.Gómez-Tejedor, JA.; Castro Palacio, JC.; Monsoriu Serra, JA. (2014). Direct measurement of the speed of sound using a microphone and a speaker. Physics Education. 49(3):310-313. doi:10.1088/0031-9120/49/3/310S310313493LoPresto, M. C. (2011). Experimenting with end-correction and the speed of sound. Physics Education, 46(4), 437-439. doi:10.1088/0031-9120/46/4/011Ng, Y., & Mak, S. (2000). Measurement of the speed of sound in water. Physics Education, 36(1), 65-70. doi:10.1088/0031-9120/36/1/312Mak, S., Ng, Y., & Wu, K. (2000). Measurement of the speed of sound in a metal rod. Physics Education, 35(6), 439-445. doi:10.1088/0031-9120/35/6/311Albergotti, J. C. (1981). Speed of sound by a time‐of‐flight method. American Journal of Physics, 49(6), 595-596. doi:10.1119/1.12466Ouseph, P. J., & Link, J. J. (1984). Variation of speed of sound in air with temperature. American Journal of Physics, 52(7), 661-661. doi:10.1119/1.1387
Detection of brucella melitensis by bactec NR 730 and bactec 9120 systems
No full textIn many parts of the world, brucellosis has significantly decreased, but it is still a problem in some regions of Turkey. In our laboratory we have isolated 58 Brucella spp. through BACTEC NR 730 and 30 Brucella spp. through BACTEC 9120 systems. 31 of the 58 isolates were detected by BACTEC NR 730 system in 72 hours. The majority of the growth values were between 45-65. BACTEC 9120 system detected all the isolates in 84 hours
Connectance and stability of nonlinear symplectic systems
No full textCelestial Mechanics and Dynamical Astronomy, 102, pp. 3-12, http://dx.doi.org./10.1007/s10569-008-9120-2International audienc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluación del analizador hematológico de impedancia eléctrica BAKER 9120+ con sangre de perro y gato
Full text linkEl objetivo de este trabajo es evaluar el analizador hematológico automático de impedancia eléctrica, Baker 9120+ (Menarini Diagnóstica S.A.), con sangre de perro y gato. La precisión intra e interensayo y la reproducibilidad del Baker 9120+ es excelente para todos los parámetros en ambas especies. El arrastre y la linealidad del analizador hematológico es muy buena para todos los parámetros, a excepción del recuento de plaquetas con sangre felina, debido a la sobreposición de la población eritrocitaria y plaquetar. No es posible determinar las diferentes poblaciones leucocitarias en ninguna de las dos especies, independientemente de la cantidad de hemolizante utilizado. La comparación del Baker 9120+ con otro analizador de impedancia eléctrica en el recuento celular y concentración de hemoglobina, y con el método manual para el valor hematocrito, es buena para todos los parámetros. El recuento de eritrocitos, leucocitos y la concentración de hemoglobina son estables durante las 72 horas postextracción, tanto a temperatura ambiente como en refrigeración. El recuento de plaquetas en sangre de perro desciende rápidamente con diferencias significativas a las 4 horas postextracción en las muestras refrigeradas y a las 24 horas en las muestras mantenidas a temperatura ambiente.An authomated blood cell analyser (Baker 9120+) was evaluated with canine and feline blood. Precision and reproducibility were excelent in both species for all the parameters. Carry-over and linearity was very good for all the parameters, except for the platelet count due to the overlapping between erythrocyte and platelet population. There was not possible to differenciate any of the leukocyte populations with the Baker 9120+. The comparability between the Baker 9120+ and another electric impedance analyzer for blood cell count and hemoglobin concentration and the microhematocrit method for the haematocrit value was good for all the parameters. Red blood cell, white blood cell count and haemoglobin concentration are stable during 72 hours after the extraction at 4 ºC and 25 ºC.Canine platelet count dropped significantly at 4 hours post- extraction in those samples stored at 4 "C and after 24 hours in those samples at room temperature
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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