High-dimensional Z-stable AH algebras

Peer reviewed

Corrigendum to “Regularity for Stably Projectionless, Simple C ∗ -Algebras”

Peer reviewed

High-dimensional Z-stable AH algebras

Peer reviewed

Perceptions of Underprepared Community College Students regarding their Educational Achievement

The purpose of this study was to understand the perceptions of underprepared college students who had participated in learning communities and who persisted to complete developmental classes and earned at least 30 college-level credit hours to graduate and the perceptions of their peers who had dropped out of college. The theories posed by Tinto, Astin, and Freire formed the framework for this case study. The 22 participants were graduates or transfer students now attending a public university, currently-enrolled sophomores, and students no longer enrolled at the time of the study. Semi-structured individual interviews and a group interview provided narrative data which were transcribed, coded, and analyzed to gain insights into the experiences and perspectives of the participants. The group interview provided a form of member checking to increase accuracy in interpreting themes. A peer reviewer provided feedback on the researcher’s data analysis procedures. The analysis yielded four themes and 14 sub-themes which captured the essence of the participants’ experiences. The pre-college characteristics/traits theme described the students’ internal values and attributes acquired prior to college. The external college support/community influence theme described the encouragement to attend college the students received from family, friends, and high school teachers. The social involvement theme described the students’ participation in campus activities and their interactions with other members of the campus. The academic integration theme described students’ use of campus resources and their contacts with the faculty. The persisters reported strong family and peer support, a sense of responsibility, appreciation for dedicated and caring faculty, and a belief that an education can be a liberatory means to achieve their goals. The non-persisters did not report having the same sense of purpose, goal orientation, determination, obligation to meet family expectations, peer support, campus involvement, positive faculty experiences, and time management skills. The researcher offers an emerging model for understanding factors associated with persistence and three recommendations for enhancing the academic experience of underprepared college students: (a) include a critical pedagogy perspective in coursework where possible, (b) integrate co-curricular activities with the academic disciplines, and (c) increase student-faculty interaction.

Tarpon Bay

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Fossil associations from the middle and upper Eocene strata of the Pamplona Basin and surrounding areas (Navarre, western Pyrenees)

Fossil associations from the middle and upper Eocene (Bartonian and Priabonian) sedimentary succession of the Pamplona Basin are described. This succession was accumulated in the western part of the South Pyrenean peripheral foreland basin and extends from deep-marine turbiditic (Ezkaba Sandstone Formation) to deltaic (Pamplona Marl, Ardanatz Sandstone and Ilundain Marl formations) and marginal marine deposits (Gendulain Formation). The micropalaeontological content is high. It is dominated by foraminifera, and common ostracods and other microfossils are also present. The fossil ichnoasssemblages include at least 23 ichnogenera and 28 ichnospecies indicative of Nereites, Cruziana, Glossifungites and ?Scoyenia-Mermia ichnofacies. Body macrofossils of 78 taxa corresponding to macroforaminifera, sponges, corals, bryozoans, brachiopods, annelids, molluscs, arthropods, echinoderms and vertebrates have been identified. Both the number of ichnotaxa and of species (e. g. bryozoans, molluscs and condrichthyans) may be considerably higher. Body fossil assemblages are comparable to those from the Eocene of the Nord Pyrenean area (Basque Coast), and also to those from the Eocene of the west-central and eastern part of South Pyrenean area (Aragon and Catalonia). At the European scale, the molluscs assemblages seem endemic from the Pyrenean area, although several Tethyan (Italy and Alps) and Northern elements (Paris basin and Normandy) have been recorded. Palaeontological data of studied sedimentary units fit well with the shallowing process that throughout the middle and late Eocene occurs in the area, according to the sedimentological and stratigraphical data.

Strontium isotopes and sedimentology of a marine Triassic succession (upper Ladinian) of the westernmost Tethys, Spain

Chemical Stratigraphy, or the study of the variation of chemical elements within sedimentary sequences, has gradually become an experienced tool in the research and correlation of global geologic events. In this paper 87Sr/ 86Sr ratios of the Triassic marine carbonates (Muschelkalk facies) of southeast Iberian Ranges, Iberian Peninsula, are presented and the representative Sr-isotopic curve constructed for the upper Ladinian interval. The studied stratigraphic succession is 102 meters thick, continuous, and well preserved. Previous paleontological data from macro and micro, ammonites, bivalves, foraminifera, conodonts and palynological assemblages, suggest a Fassanian-Longobardian age (Late Ladinian). Although diagenetic minerals are present in small amounts, the elemental data content of bulk carbonate samples, especially Sr contents, show a major variation that probably reflects palaeoenvironmental changes. The 87Sr/86Sr ratios curve shows a rise from 0.707649 near the base of the section to 0.707741 and then declines rapidly to 0.707624, with a final values rise up to 0.70787 in the upper part. The data up to meter 80 in the studied succession is broadly concurrent with 87Sr/86Sr ratios of sequences of similar age and complements these data. Moreover, the sequence stratigraphic framework and its key surfaces, which are difficult to be recognised just based in the facies analysis, are characterised by combining variations of the Ca, Mg, Mn, Sr and CaCO3 contents

¿Fue la crisis política del Occidente musulmán del siglo XIII debida a un cambio climático? Una aproximación histórica al fin del Periodo Cálido Medieval

Durante el siglo XIII se produjo una sucesión de revueltas que supuso la desaparición del Imperio almohade y su sustitución por poderes regionales en al-Andalus, el Magreb y el Magreb al-Aqsà. La historiografía ha presentado el surgimiento y pugna entre estos poderes como un fenómeno social, político e, incluso, cultural y religioso, con el que se ha podido explicar su aniquilación o marginalización. Este trabajo pretende contextualizar los hechos desde una perspectiva medioambiental, de forma que la desintegración del califato almohade, el surgimiento de aquellos poderes y la progresión de los reinos cristianos en la península ibérica puedan entenderse desde una visión global de cambio climático y una posible crisis agrícola.

El clima intuido en el Madrid medieval a través de sus documentos y del Libro de la Montería (siglos XIV-XVI)

El presente trabajo pretende analizar cuáles eran las características climáticas que se sucedían en Madrid y su Tierra a lo largo del año, fundamentalmente entre los siglos XIV y XVI. Se intentará comprobar, dentro de las limitaciones que impone la documentación de la época, si en aquel tiempo se daba también un clima mediterráneo, o no, y si este ha variado mucho desde entonces. Igualmente se podrá comprobar algo que tal vez podría, aunque no debería, sorprendernos: el hombre medieval tenía muy claros muchos conceptos meteorológicos y climatológicos, aunque siempre aprehendidos con una finalidad práctica, para aplicarlos en su vida cotidiana tan cercana y dependiente de la naturaleza.

FEM Analysis to Optimally Design End Mill cutters for Milling of Ti-6Al-4V

This paper presents an FEM analysis conducted for optimally designing end mill cutters through verifying the cutting tool forces and stresses for milling Titanium alloy Ti-6Al-4 V. Initially, the theoretical tool forces are calculated by considering the cutting edge on a cutting tool as the curve of an intersection over a spherical/flat surface based on the model developed by Lee & Altinas [1]. Considering the lowest tool forces the cutting tool parameters are taken and optimal design of end mill is decided for different sizes. Then the 3D CAD models of the end mills are developed and used for Finite Element Method to verify the cutting forces for milling Ti-6Al-4 V. The cutting tool forces, stress, strain concentration (s), tool wear, and temperature of the cutting tool with the different geometric shapes are simulated considering Ti-6Al-4 V as work piece material. Finally, the simulated and theoretical values are compared and the optimal design of cutting tool for different sizes are validated. The present approach considers to improve the quality of machining surface and tool life with effects of the various parameters concerning the oblique cutting process namely axial, radial and tangential forces. Various simulated test cases are presented to highlight the approach on optimally designing end mill cutters.

Feature recognition & tool path generation for 5 axis step-nc machining of free form / irregular contoured surfaces

This research paper presents a five step algorithm to generate tool paths for machining Free form / Irregular Contoured Surface(s) (FICS) by adopting STEP-NC (AP-238) format. In the first step, a parametrized CAD model with FICS is created or imported in UG-NX6.0 CAD package. The second step recognizes the features and calculates a Closeness Index (CI) by comparing them with the B-Splines / Bezier surfaces. The third step utilizes the CI and extracts the necessary data to formulate the blending functions for identified features. In the fourth step Z-level 5 axis tool paths are generated by adopting flat and ball end mill cutters. Finally, in the fifth step, tool paths are integrated with STEP-NC format and validated. All these steps are discussed and explained through a validated industrial component.

Relatório de estágio para obtenção do grau de mestre em educação Pré-Escolar e Ensino do 1º Ciclo do Ensino Básico

O presente relatório tem como intuito a obtenção do grau de mestre em Educação Pré-Escolar e 1.º Ciclo do Ensino Básico, alicerçando-se em torno das práticas pedagógicas vivenciadas nos dois níveis de ensino supramencionados. Por conseguinte, estas intervenções concretizaram-se na EB1/PE da Achada, nomeadamente na turma do 4.ºA, no período entre 13 de outubro e 15 de dezembro e no Infantário “O Carrocel”, na sala laranja, de 6 de abril a 3 de junho. Visando uma prática estruturada e adequada aos grupos em questão e a real construção de aprendizagens significativas, primeiramente serão revelados os pressupostos teóricos e metodológicos que guiaram todo este percurso e permitiram que as crianças fossem elas próprias as construtoras da sua aprendizagem. Não obstante, a observação e a reflexividade na docência foram pontos igualmente primordiais na identificação de problemáticas, mais concretamente no âmbito das competências comunicativas e sociais de ambos os grupos, sendo estas desenvolvidas em torno da metodologia de Investigação-Ação. Desta forma, as questões encontradas foram respetivamente Como desenvolver competências de comunicação em crianças com dificuldades nesta área?, no que concerne ao grupo do 4.ºA, e Como desenvolver as relações interpessoais e de pares num grupo de crianças de PréEscolar?, relativamente ao grupo da sala laranja. Por outro lado, a organização de todo o ambiente educativo e as sequências didáticas, a partir das quais toda a práxis se sucedeu, ocuparão um lugar de destaque no corpo deste relatório. Sendo por fim, tecido todo o processo de reflexão após o culminar destas duas práticas pedagógicas, que evidenciaram o primeiro desafio enquanto futura profissional da área da educação e consistirão claramente na base para um longo e contínuo percurso de formação.

Spectral synthesis and topologies on ideal spaces for Banach *-algebras

This paper continues the study of spectral synthesis and the topologies τ∞ and τr on the ideal space of a Banach algebra, concentrating on the class of Banach *-algebras, and in particular on L1-group algebras. It is shown that if a group G is a finite extension of an abelian group then τr is Hausdorff on the ideal space of L1(G) if and only if L1(G) has spectral synthesis, which in turn is equivalent to G being compact. The result is applied to nilpotent groups, [FD]−-groups, and Moore groups. An example is given of a non-compact, non-abelian group G for which L1(G) has spectral synthesis. It is also shown that if G is a non-discrete group then τr is not Hausdorff on the ideal lattice of the Fourier algebra A(G).