A laboratory method for precisely determining the micro-volume-magnitudes of liquid efflux

Micro-volumetric quantities of ejected liquid are made to produce equal volumetric displacements of a more dense material. Weight measurements are obtained on the displaced heavier liquid and used to calculate volumes based upon the known density of the heavy medium

THE EFFECTS OF THEMATIC SOCIAL STUDIES INSTRUCTION ON EIGHTH GRADE STUDENTS’ HISTORICAL REASONING ABILITY AND ATTITUDES TOWARDS SOCIAL STUDIES RELATED TASKS

This study examined the potential benefits of thematic-based social studies instruction on middle school students’ historical reasoning ability and attitudes towards social studies related tasks. Thematic instruction refers to a curriculum delivery that is based on themes in history, such as: wealth, discovery, and conflict. Using a sample of convenience (n = 211) from two suburban New England middle schools, this quasi-experimental study included a pretest and posttest of student attitudes towards social studies related tasks (Interest in Science, Technology, Writing Tasks, Interest in Social Studies, and Student Perspective Taking) and an analysis of student writing. The study utilized a mixed-methods approach, where students from a thematic-based social studies program (n = 98) were compared to those in nonthematic-based program (n = 113). During the course of the research three writing prompts were given and scored via a rubric to measure students’ historical reasoning ability. A focus group of students was created from each condition to define the attitudes and perceptions of students in the two different programs. The results indicated that students in the thematic-based social studies program had significantly higher attitudes towards social studies as compared to their peers in the nonthematic-based program (Pillai’s trace = .118, F(6,203) = 4.541, p \u3c .001). There were no significant differences between groups regarding historical reasoning skills. Student comments about the program were related to the themes of: (a) Attitudes Towards Social Studies, (b) Curriculum Strategies, Organization and Procedures, and (c) Higher Level Thinking Skills. Educational implications include insights into classroom activities that promote historical reasoning and writing in relation to assessment in social studies

Ludwig van Beethoven\u27s orchestration of the trombone

Ludwig Van Beethoven is considered one of the first composers to fully realize the wide-ranging performance potential of the trombone. Although the instrument had already been scored in sacred and operatic works by major composers (and symphonies by lesser-known composers), it was Beethoven who was considered to be the first to truly emancipate the trombone from its sacred and operatic boundaries and write for it in various secular, choral, and even chamber music genres. In this paper, every composition of Beethoven\u27s that includes trombones is examined. The historical context of each individual work will be established, along with any general trombone-related observations from the work in question. Musical examples from each work will be examined in detail, with the view of elucidating compositional techniques such as melodic and solo usage, doubling, range, dynamic range, percentage of measures actually played, and placement within orchestration. Comparisons between genres and time periods will also be made, with the objective being to establish patterns of musical evolution---if any---across time or between genres

Inventaire des mauvaises herbes dans les pépinières ornementales du Québec

Un inventaire des mauvaises herbes réalisé au cours de l'été 1986 a permis de visiter 53% des superficies en production ornementale au Québec. Les infestations de mauvaises herbes étaient maintenues à de faibles niveaux dans les pépinières visitées grâce aux sarclages manuels et aux hersages mécaniques fréquents. L'inventaire a révélé que les mauvaises herbes vivaces étaient les plus difficiles à réprimer dans les pépinières. Les mauvaises herbes vivaces les plus fréquemment rencontrées étaient la vesce jargeau (Vicia cracca), le chiendent (Agropyron repens), la prèle des champs (Equisetum arvense) et le souchet comestible (Cyperus esculentus). Les mauvaises herbes identifiées dans les pépinières étaient, pour la plupart, des espèces communes à d'autres cultures. Toutefois, la rorippe d'Islande (Rorippa islandica), la rorippe sylvestre (Rorippa sylvestris) et la cardamine de Pennsylvanie (Cardamine pensylvanica), mauvaises herbes moins connues, ont démontré un fort potentiel d'envahissement dans les pépinières ornementales.A weed survey of fields in ornamental production was conducted in Quebec in 1986 during which 53 % of the production sites were visited. Because of the intensity of hand-weeding and mechanical cultivation used in the fields, no major weed infestations were observed. Weeds most difficult to control were mainly perennial species such as tufted vetch (Vicia cracca), quackgrass (Agropyron repens), field horsetail (Equisetum arvense), and yellow nutsedge (Cyperus esculentus). Most of the weeds identified were species common to other crops. However, marsh yellow cress (Rorippa islandica), yellow field cress (Rorippa sylvestris), and bitter cress (Cardaminepensylvanica) were lesser known weed species that showed a great potential of increase in ornamental nursery production

Newinsights in the ontogeny and taphonomy of the Devonian acanthodian Triazeugacanthus affinis from the Miguasha Fossil-Lagerstatte, Eastern Canada

Progressive biomineralization of a skeleton occurs during ontogeny in most animals. In fishes, larvae are poorly mineralized, whereas juveniles and adults display a progressively more biomineralized skeleton. Fossil remains primarily consist of adult specimens because the fossilization of poorly-mineralized larvae and juveniles necessitates exceptional conditions. The Miguasha Fossil-Lagerstatte is renowned for its Late Devonian vertebrate fauna, revealing the exceptional preservation of fossilized ontogenies for 14 of the 20 fish species from this locality. The mineralization of anatomical structures of the acanthodian Triazeugacanthus affinis from Miguasha are compared among larval, juvenile and adult specimens using Energy Dispersive X-ray Spectrometry. Chemical composition of anatomical structures of Triazeugacanthus reveals differences between cartilage and bone. Although the histology and anatomy is well-preserved, Fourier transform infrared spectrometry shows that the original chemical composition of bone is altered by diagenesis; the mineral phase of the bone (i.e., hydroxyapatite) is modified chemically to form more stable carbonate-fluorapatite. Fluorination occurring in mineralized skeletal structures of adult Triazeugacanthus is indicative of exchanges between groundwater and skeleton at burial, whereas the preservation of larval soft tissues is likely owing to a rapid burial under anoxic conditions. The exceptional state of preservation of a fossilized ontogeny allowed us to characterize chemically the progressive mineralization of the skeleton in a Devonian early vertebrate

Analytical Guidance Laws and Integrated Guidance/Autopilot for Homing Missiles

An approach to integrated guidance/autopilot design is considered in this study. It consists of two parts: 1) recognizing the importance of polar coordinates to describe the end game in terms of problem description and measurement acquisition, the terminal guidance problem is formulated in terms of polar coordinates; 2a) through the use of the state transition matrix of the intercept dynamics, a closed form solution for the transverse command acceleration is obtained; and 2b) through a commonly used approximation on time-to-go and a coordinate transformation, a family of proportional navigation optimal guidance laws is obtained in a closed form. A typical element of such a guidance law is combined with the autopilot dynamics to result in a feedback control law in terms of output variable

Orientability and energy minimization in liquid crystal models

Uniaxial nematic liquid crystals are modelled in the Oseen-Frank theory through a unit vector field $n$. This theory has the apparent drawback that it does not respect the head-to-tail symmetry in which $n$ should be equivalent to -$n$. This symmetry is preserved in the constrained Landau-de Gennes theory that works with the tensor $Q=s\big(n\otimes n- \frac{1}{3} Id\big)$.We study the differences and the overlaps between the two theories. These depend on the regularity class used as well as on the topology of the underlying domain. We show that for simply-connected domains and in the natural energy class $W^{1,2}$ the two theories coincide, but otherwise there can be differences between the two theories, which we identify. In the case of planar domains we completely characterise the instances in which the predictions of the constrained Landau-de Gennes theory differ from those of the Oseen-Frank theory