529 research outputs found

    Shaping a Corporate Identity From Below; the Role of the BAT Bulletin.

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    Existing studies that have explored the use of company journals as a mode of corporate communication during the early 20th century have invariably adopted an instrumentalist view of these publications. Company journals have been seen as a means of projecting to employees a top-down view of organisations. This article identifies a counter-example in which the origins of a company journal, the 'Bat Bulletin', are seen to arise as the result of an initiative stemming from the employees themselves. These antecedents gave the 'Bat Bulletin' a high degree of legitimacy amongst staff and provided the company with an important means of establishing a unified corporate culture across a disparate group international operating companies. Over time, however, the contents of the journal gradually became more conventional, and it was eventually closed down when the strategy of international integration ceased to be a desirable corporate objective during the 1930's

    Vertebrate Natural History Notes from Arkansas, 2017

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    Because meaningful observations of natural history are not always part of larger studies, important pieces of information often are unreported. Small details, however, can fills gaps in understanding and also lead to interesting questions about ecological relationships or environmental change. We have compiled recent observations of foods, reproduction, record size, parasites, and distribution of 30 species of fishes, new records of distribution and parasites of 2 species of amphibians, and new records of distribution, parasites, reproduction and anomalies of 11 species of mammals

    Hysteresis response of daytime net ecosystem exchange during drought

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    Continuous measurements of net ecosystem CO<sub>2</sub> exchange (NEE) using the eddy-covariance method were made over an agricultural ecosystem in the southeastern US. During optimum environmental conditions, photosynthetically active radiation (PAR) was the primary driver controlling daytime NEE, accounting for as much as 67 to 89% of the variation in NEE. However, soil water content became the dominant factor limiting the NEE-PAR response during the peak growth stage. NEE was significantly depressed when high PAR values coincided with very low soil water content. The presence of a counter-clockwise hysteresis of daytime NEE with PAR was observed during periods of water stress. This is a result of the stomatal closure control of photosynthesis at high vapor pressure deficit and enhanced respiration at high temperature. This result is significant since this hysteresis effect limits the range of applicability of the Michaelis-Menten equation and other related expressions in the determination of daytime NEE as a function of PAR. The systematic presence of hysteresis in the response of NEE to PAR suggests that the gap-filling technique based on a non-linear regression approach should take into account the presence of water-limited field conditions. Including this step is therefore likely to improve current evaluation of ecosystem response to increased precipitation variability arising from climatic changes

    Starting from Where They Start

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    Qualitative differences in beginner teachers' knowledge of pupils' understandings: evidence from learning study and implications for teacher education

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    This study contributes to teacher educators’ pedagogical content knowledge by drawing on phenomenography-variation theory to i) research and describe qualitative differences in Beginner Teachers’ conceptions of pupils’ understandings of subject content and, ii) provide evidence of the effectiveness of an instructional strategy that might be adopted by teacher educators based upon those conceptions (known as ‘Learning Study’). The study identified nine possible conceptions of pupils’ understanding of the topic of ‘price’ in economics/business education with each being divided into a structural and a contextual element. These provide a useful framework for teacher educators to conceptualise Beginner Teachers’ learning about pupils’ understanding. In addition, Learning Study is shown to have a statistically significant, medium/large effect on the development of Beginner Teachers’ knowledge of pupils’ understandings in comparison to a control group. These results add to the evidence for adopting this approach more widely in teacher education

    Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae), the Cayenne tick: phylogeography and evidence for allopatric speciation

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    Background: Amblyomma cajennense F. is one of the best known and studied ticks in the New World because of its very wide distribution, its economical importance as pest of domestic ungulates, and its association with a variety of animal and human pathogens. Recent observations, however, have challenged the taxonomic status of this tick and indicated that intraspecific cryptic speciation might be occurring. In the present study, we investigate the evolutionary and demographic history of this tick and examine its genetic structure based on the analyses of three mitochondrial (12SrDNA, d-loop, and COII) and one nuclear (ITS2) genes. Because A. cajennense is characterized by a typical trans-Amazonian distribution, lineage divergence dating is also performed to establish whether genetic diversity can be linked to dated vicariant events which shaped the topology of the Neotropics. Results: Total evidence analyses of the concatenated mtDNA and nuclear + mtDNA datasets resulted in well-resolved and fully congruent reconstructions of the relationships within A. cajennense. The phylogenetic analyses consistently found A. cajennense to be monophyletic and to be separated into six genetic units defined by mutually exclusive haplotype compositions and habitat associations. Also, genetic divergence values showed that these lineages are as distinct from each other as recognized separate species of the same genus. The six clades are deeply split and node dating indicates that they started diverging in the middle-late Miocene. Conclusions: Behavioral differences and the results of laboratory cross-breeding experiments had already indicated that A. cajennense might be a complex of distinct taxonomic units. The combined and congruent mitochondrial and nuclear genetic evidence from this study reveals that A. cajennense is an assembly of six distinct species which have evolved separately from each other since at least 13.2 million years ago (Mya) in the earliest and 3.3 Mya in the latest lineages. The temporal and spatial diversification modes of the six lineages overlap the phylogeographical history of other organisms with similar extant trans-Amazonian distributions and are consistent with the present prevailing hypothesis that Neotropical diversity often finds its origins in the Miocene, after the Andean uplift changed the topology and consequently the climate and ecology of the Neotropics.Fil: Beati, Lorenza. Georgia State University; Estados UnidosFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria, Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Burkman, Erica J.. Georgia State University; Estados UnidosFil: Barros Battesti, Darcy M.. Governo Do Estado de Sao Paulo. Secretaria Da Saude. Instituto Butantan; Brasil;Fil: Labruna, Marcelo B.. Universidade do Sao Paulo; Brasil;Fil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria, Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Cáceres, Abraham G.. Instituto Nacional de Salud; PerúFil: Guzman Cornejo, Carmen. Universidad Nacional Autónoma de México; México;Fil: Léon, Renato. Universidad San Francisco de Quito; Ecuador;Fil: Durden, Lance A.. Georgia State University; Estados UnidosFil: Faccini, João L.H.. Universidade Federal Rural Do Rio de Janeiro; Brasi

    Linking a City\u27s Culture to Students\u27 Learning

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    The aquarium, the theater, and the zoo are some of the possible classrooms in The Baltimore learning Network\u27s model learning community

    The key physical parameters governing frictional dissipation in a precipitating atmosphere

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    Precipitation generates small-scale turbulent air flows the energy of which ultimately dissipates to heat. The power of this process has previously been estimated to be around 2-4 W m-2 in the tropics: a value comparable in magnitude to the dynamic power of the global circulation. Here we suggest that this previous power estimate is approximately double the true figure. Our result reflects a revised evaluation of the mean precipitation path length Hp. We investigate the dependence of Hp on surface temperature,relative humidity,temperature lapse rate and degree of condensation in the ascending air. We find that the degree of condensation,defined as the relative change of the saturated water vapor mixing ratio in the region of condensation, is a major factor determining Hp. We estimate from theory that the mean large-scale rate of frictional dissipation associated with total precipitation in the tropics lies between 1 and 2 W m-2 and show that our estimate is supported by empirical evidence. We show that under terrestrial conditions frictional dissipation constitutes a minor fraction of the dynamic power of condensation-induced atmospheric circulation,which is estimated to be at least 2.5 times larger. However,because Hp increases with surface temperature Ts, the rate of frictional dissipation would exceed that of condensation-induced dynamics, and thus block major circulation, at Ts >~320 K in a moist adiabatic atmosphere.Comment: 12 pp, 2 figure

    Improving teacher learning: variation in conceptions of learning study

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    Purpose: The purpose of this paper is to identify teachers’ conceptions of learning study in order to provide the basis for an application of phenomenography/variation theory (PVT) to the improvement of teachers’ learning about learning study. / Design/methodology/approach: A phenomenographic study based on semi-structured interviews with 18 beginner teachers of business and economics in England taking part in a learning study during their initial teacher education. / Findings: The study identified five conceptions of learning study and five associated critical aspects. Results raise questions about the relationship between the process and instructional design elements of learning study. / Originality/value: The study offers a framework for exploring differences in the quality of learning studies and the relationship between teacher conceptions of learning study and the degree of conceptual change in students in a learning study. It also enables facilitator/researchers to design and manage interventions to develop teacher understanding of learning study that are consistent with the principles of PVT
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