Objective measures of voice production in patients complaining of laryngeal fatigue

The purpose of this retrospective study is to describe results of acoustic, aerodynamic, and videostroboscopic measures in patients complaining of laryngeal fatigue. Data were collected from 88 patients whose primary complaint was chronic laryngeal fatigue in the absence of visible laryngeal pathologies. The results revealed an abnormally high airflow rate and decreased maximum phonation time. An anterior glottal chink, anterior and posterior glottal chinks, or spindle-shaped glottal closure were found in 61% of the subjects.     

Vanadium and chromium redox behavior in borosilicate nuclear waste glasses

X-ray absorption spectroscopy (XAS) was used to characterize vanadium (V) and chromium (Cr) environments in low activity nuclear waste (LAW) glasses synthesized under a variety of redox conditions. V₂O₅ was added to the melt to improve sulfur incorporation from the waste; however, at sufficiently high concentrations, V increased melt foaming, which lowered melt processing rates. Foaming may be reduced by varying the redox conditions of the melt, while small amounts of Cr are added to reduce melter refractory corrosion. Three parent glasses were studied, where CO-CO₂ mixtures were bubbled through the corresponding melt for increasing time intervals so that a series of redox-adjusted-glasses was synthesized from each parent glass. XAS data indicated that V and Cr behaviors are significantly different in these glasses with respect to the cumulative gas bubbling times: V⁴⁺/V_total ranges from 8 to 35%, while Cr³⁺/Cr_total can range from 15 to 100% and even to population distributions including Cr²⁺. As Na-content decreased, V, and especially, Cr became more reduced, when comparing equivalent glasses within a series. The Na-poor glass series show possible redox coupling between V and Cr, where V⁴⁺ populations increase after initial bubbling, but as bubbling time increases, V⁴⁺ populations drop to near the level of the parent glass, while Cr becomes more reduced to the point of having increasing Cr²⁺ populations.     

Influence of cation on charge recombination in dye-sensitized TiO2 electrodes

The reaction of a dye cation recombining with an electron in TiO(2), in the presence of Li(+), Ca(2+), and TBA(+) cations, was studied with laser-induced transient absorption measurements. The active cations, Li(+) and Ca(2+), shorten the dye cation lifetime on sensitized TiO(2) but not ZnO electrodes. By combining the absorbance measurements of the dye cation with simultaneous measurements of the current transient, the contribution of the recombination reaction to the current is identified. Furthermore, classical porous electrode theory is used to quantify the behavior of the heterogeneous electrode, and in doing so, the processes contributing to photoinduced current are identified as Helmholtz layer charging, porous electrode charging, recombination reactions, and surface diffusion of the active cations. The rate of charge recombination is proportional to the concentration of initially deposited active cations. The effect of water on the recombination rate and the current is also observed.     

(2)-pancyclic graphs

We introduce the class of (2)-pancyclic graphs, which are simple undirected finite connected graphs of order $n$ having exactly two cycles of length $p$ for each $p$ satisfying $3\le p\le n$, analyze their properties, and give several examples of such graphs, among which are the smallest.     

A magnetic resonance imaging-based articulatory and acoustic study of "retroflex" and "bunched" American English /r/

Speakers of rhotic dialects of North American English show a range of different tongue configurations for /r/. These variants produce acoustic profiles that are indistinguishable for the first three formants [Delattre, P., and Freeman, D. C., (1968). "A dialect study of American English r's by x-ray motion picture," Linguistics 44, 28-69; Westbury, J. R. et al. (1998), "Differences among speakers in lingual articulation for American English /r/," Speech Commun. 26, 203-206]. It is puzzling why this should be so, given the very different vocal tract configurations involved. In this paper, two subjects whose productions of "retroflex" /r/ and "bunched" /r/ show similar patterns of F1-F3 but very different spacing between F4 and F5 are contrasted. Using finite element analysis and area functions based on magnetic resonance images of the vocal tract for sustained productions, the results of computer vocal tract models are compared to actual speech recordings. In particular, formant-cavity affiliations are explored using formant sensitivity functions and vocal tract simple-tube models. The difference in F4/F5 patterns between the subjects is confirmed for several additional subjects with retroflex and bunched vocal tract configurations. The results suggest that the F4/F5 differences between the variants can be largely explained by differences in whether the long cavity behind the palatal constriction acts as a half- or a quarter-wavelength resonator.     

The garner heavy duty quartz fiber microbalance

Summary A Garner balance is described which by means of a vertical suspension fiber is said to be capable of weighing a 5-g load with a sensitivity better than that attainable with the ordinary knife-edge balance. Its weighing chambers were especially designed to accommodate light absorption tubes for the determination of carbon and hydrogen. A practical system for eliminating vibration and furnishing a suitable mounting for sensitive quartz fiber balances in the industrial laboratory is also reported. Under a 5-g load, the Garner balance was found to give strict proportionality within±0.001 mg between torsion and weight. It reproduces within ±0.26g when weighing a 0.4-g platinum boat with the torsion fiber under continuous strain.

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Zusammenfassung Eine Garner Mikrowaage mit Quarzbalken wird beschrieben, deren Empfindlichkeit die der üblichen, auf Schneiden ruhenden Feinwaagen übertrifft und die doch eine Last von 5 g tragen kann, da der Balken von einem vertikalen Quarzfaden getragen wird. Die Gehänge und Gehängekammern wurden zur Aufnahme von leichten Absorptionsapparaten speziell entworfen. Eine für das Industrielaboratorium geeignete, praktische Aufstellung der Waage, die störende Vibrationen ausschließt, wird beschrieben. Unter Maximalbelastung von 5 g wurde Proportionalität innerhalb±0,001 mg zwischen Gewicht und kompensierender Torsionskraft festgestellt. Das Gewicht eines Platinschiffchens (0,4 g) konnte mit einem mittleren Fehler von ±0,26g reproduziert werden, wenn der horizontale Torsionsfaden aus Quarz ständig unter Torsionsspannung gehalten wurde.

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Résumé On décrit une balance de Garner qui, au moyen d'un fil de suspension vertical, est capable de peser une charge de 5 g avec une sensibilité meilleure que celle que l'on obtient avec une balance à couteau ordinaire. Ses compartiments ont été spécialement agencés pour loger les tubes d'absorption légers pour le dosage du carbone et de l'hydrogène. On donne aussi un système pratique pour éliminer les vibrations et pour fournir un montage convenable pour les balances à fil de quartz sensibles dans les laboratoires industriels. Sous une charge de 5 g, on a trouvé que la balance de Garner donne une proportionnalité rigoureuse à moins de±0,001 mg entre la torsion et le poids. Elle donne une valeur reproductible à moins de±0,26g pour une nacelle de platine de 0,4 g pour le fil de torsion soumis à un effort constant.

     

Crystal structure ofmer,trans-[Ru(NO2)(trpy)(PPr3) 2 + ][ClO 4 − ], a species with disordered PPr3 and NO2 ligands

The complexmer,trans-[Ru(NO₂)(trpy)(PPr₃) ₂ ⁺ ][ClO ₄ ^– ]crystallizes in the centrosymmetric orthorhombic space group Pnma withZ=4. Both the ruthenium(II) cation and the perchlorate ligand lie about crystallographic mirror planes. The nitro ligand is not coplanar with the Ru(trpy) moiety and suffers from two fold disorder about its Ru–N bond such that the two sets of oxygen atoms have symmetry-related sites above or below the crystallographic mirror plane. The n-propyl groups within the PPr₃ ligands suffer from disorder of their C() and C() atoms but share common C() sites. Ruthenium-ligand distances are: Ru–PPr₃=2.398(2)Å, Ru–NO₂=2.053(7) Å, Ru–N(trpy, outer)=2.078(6) and 2.092(6) Å and Ru–N(trpy, central) =1.965(6) Å.     

Characterizing STEM Teacher Education: Affordances and Constraints of Explicit STEM Preparation for Elementary Teachers

Although science, technology, engineering, and mathematics (STEM) education sits at the center of a national conversation, comparatively little attention has been given to growing need for STEM teacher preparation, particularly at the elementary level. This study analyzes the outcomes of a novel, preservice STEM teacher education model. Building on both general and STEM‐specific teacher preparation principles, this program combined two traditional mathematics and science methods courses into one STEM block. Analysis compared preservice teachers in the traditional courses with those enrolled in the STEM block, investigating STEM teaching efficacy, reported and exhibited pedagogical practices, and STEM literacies using a pre‐post survey as well as analysis of lesson planning products. Linear regression models indicated that substantial growth was seen in both approaches but STEM block preservice teachers reported significantly greater gains in STEM teaching efficacy as compared with traditional‐route teachers. Lesson planning artifacts also demonstrated increased facilitation of STEM literacies, with specific attention to content integration, engineering and design, and arts inclusion. Technology and computational thinking emerged as areas for further growth and clarification in STEM teacher education models. Findings contribute to a growing research base on developing the STEM teacher workforce.     

From formal standards to everyday practice of mathematics learning

This paper uses the example of six Japanese teachers and their mathematics lessons to illustrate how clear, high standards for mathematics instruction are combined with teachers' holistic concern for students. We draw upon data from the Third International Math and Science Study Case Study Project in Japan that was designed to elucidate the context behind the high achievement of Japanese students. Using everyday examples of classroom practice, we illustrate both flexibility in teachers' approach to teaching and adherence to Monbusho's (Ministry of Education, Science, Sports, and Culture)Course of Study. Our purpose is to emphasize how flexibility and attention to individual needs by Japanese teachers combine with quality mathematics instruction based on the detailed Japanese curricula. Six teachers' characteristics and lessons (two teachers at each educational level—elementary, junior high, and high school) are described in order to show the variety of teachers who exist in Japan. These teachers use their understanding of theCourse of Study and are supported by their school environment to enhance their students' conceptual understanding of the fundamentals of mathematics. Characteristics of their teaching include: 1) involving the whole class in learning. 2) using extremely focused curriculum guidelines that expect mastery of concepts at each grade level, 3) thoroughly covering mathematics units in an organized and in-depth manner, 4) leading classes as facilitators or guides more often than as lecturers, and 5) focusing on problem solving with the primary goal of developing students' ability to reason, especially to reason inductively. The examples in this paper show how these methods develop in individal classrooms.     

Synthesis of p-Phenylene Sulfide Molecular Asterisks

“Megastars” with aromatic central cores, some of which fluoresce, were synthesized by the efficient connection of the side arms to the core by using the MacNicol reaction. Depending on the length of the side arm precursor, second-, third- (depicted), or fourth-generation molecular asterisks were obtained; a twelve-armed molecular asterisk was prepared when the benzene core was replaced by a coronene one.