2,302 research outputs found
Local texture and percolative paths for long-range conduction in high critical current density TlBaâCaâCuâOâââ deposits
©1994 American Institute of Physics. The electronic version of this article is the complete one and can be found online at: http://link.aip.org/link/?APPLAB/64/106/1DOI:10.1063/1.110908A possible microstructural origin of the high critical current densities which have been obtained in c-axis-aligned, polycrystalline TlBaâCaâCuâOâââdeposits has been identified. The results of x-ray diffraction determinations of basal plane texture of Tl-1223 deposits prepared by spray pyrolysis are observed to depend on the size of the x-ray beam. Furthermore, most grain boundaries were found from transmission electron microscopy to have small misorientation angles. It is concluded that although overall the basal plane orientations are nearly random, there is a high degree of local texture indicative of colonies of similarly oriented grains. The spread in a-axis orientation within a colony is ~10°â15°. Intercolony conduction, it is suggested, may be enhanced by a percolative network of small-angle grain boundaries at colony interfaces
Immature stages of Spodoptera eridania (Lepidoptera: noctuidae): developmental parameters and host plants.
This study aimed to detail the temporal and morphological parameters of the immature stages of southern armyworm Spodoptera eridania (Stoll, 1782) with larvae feed on artificial diet, under controlled conditions (25?±?1°C, 70?±?10% relative humidity and 14-h photophase) and gather information about their larval host plants. The viability of the egg, larval, pupal, and prepupal stages was 97.82, 93.62, 96.42, and 97.03%, respectively. The average duration of the egg, larval, pupal, and pre-pupal stages was 4.00, 16.18, 1.58, and 9.17 d, respectively. During the larval stage, 43.44% of females passed through seven instars, observing that the female's development was significant slower than males. The female larvae that developed through six and seven instars exhibited a mean growth rate of 1.52 and 1.44, respectively. Female pupae were significantly larger, exhibiting faster development than males. The rearing method proved to be adequate, providing more detailed observations of the biological cycle, especially at the larval stage, and resulting in an overall survival of almost 85%. Two hundred two plant species belonging to 58 families are listed as natural hosts for S. eridania, mainly including Asteraceae, Fabaceae, Solanaceae, Poaceae, Amaranthaceae, and Malvaceae
Faculty Preparedness to Teach Students with Learning Disabilities: Developing an Instrument to Assess Faculty Perceptions
Despite increasing rates of entry, students with learning disabilities (LD) continue to face barriers to completing post-secondary education. Faculty attitudes and knowledge are important factors in supporting students with LD, yet little is known about faculty preparation. No valid, reliable, easy-to-administer inventory exists to assess the perceptions of faculty about their preparedness for the task of teaching students with LD. The Faculty Preparedness Questionnaire (FPQ) was developed to measure faculty perceptions of preparedness for teaching students with LD based on two factors: knowledge and attitude. For this study, 101 community college instructors completed the original questionnaire consisting of 22 items. After factor analysis, the 17-item FPQ was determined to be a reliable and valid instrument for the measurement of instructor attitudes and knowledge as components of their perceptions of preparedness. This research contributes to the current dialogue regarding best practice for inclusive post-secondary education
Immature development of Spodoptera dolichos (Fabricius) (Lepidoptera: noctuidae).
We provide detailed temporal and morphological parameters of the immature stages of Spodoptera dolichos (Fabricius) larvae fed on artificial diet under controlled conditions (25?±?1°C, 70?±?10% RH, and 14 h photophase). The viability of the egg, larval, pupal, and prepupal stages was 97.5%, 97.0%, 93.1%, and 98.9%, respectively. The average duration of the egg, larval, prepupal, and pupal stages was 5.0, 23.4, 3.2, and 21.5 days, respectively. Females took longer at the larval stage than males, with 10.5% of them having seven instars. The growth rate of female larvae that developed through six and seven instars was 1.72 and 1.54, respectively. Female pupae were significantly larger, exhibiting slower development than males
Spodoptera frugiperda (Lepidoptera: Noctuidae) updated host plants and new records.
ConteĂșdo do volume 2: Ăcaros; Biologia, fisiologia, morfologia; Controle biolĂłgico com bactĂ©rias entomopatogĂȘnicas; Controle biolĂłgico com fungos entomopatolĂłgicos; Controle biolĂłgico com nematoides; Controle biolĂłgico com parasitoides; Controle biolĂłgico com predadores; Ecologia e biodiversidade; Educação e etnoentomologia; Entomologia florestal; Entomologia Forense; Entomologia mĂ©dica e veterinĂĄria; Entomologia molecular; Manejo integrado de pragas; Organismos geneticamente modificados; Plantas inseticidas; Polinização; Pragas quarentenĂĄrias e invasivas; ResistĂȘncia de insetos a tĂĄticas de controle; ResistĂȘncia de plantas a insetos; SemioquĂmicos e comportamento; SistemĂĄtica e taxonomia; Tecnologia de aplicação; Controle biolĂłgico com vĂrus entomopatogĂȘnicos; Controle quĂmico
Efeito do tamanho e de mĂșltiplos casais sobre o potencial reprodutivo de Spodoptera eridania (Stoll, 1782) (Lepidoptera: Noctuidae).
Entre os lepidĂłpteros de importĂąncia agrĂcola, Spodoptera eridania (Stoll, 1782) tem despertado atenção por atingir nĂveis de dano econĂŽmico em culturas de importĂąncia como algodĂŁo e soja. Entretanto, existem poucos estudos detalhados de biologia, especialmente relacionados a aspectos reprodutivos. Visando determinar a capacidade mĂĄxima reprodutiva desta espĂ©cie avaliou-se o efeito do tamanho, empregando como parĂąmetro o peso pupal, e o nĂșmero de casais por gaiola (um e trĂȘs) sobre o nĂșmero de cĂłpulas, fecundidade e fertilidade. Os experimentos foram conduzidos em sala climatizada (25 ± 1ÂșC, 70 ± 10% UR e fotofase de 14 horas) com observaçÔes diĂĄrias. Adultos, emergidos no mesmo dia, classificados de acordo com a massa pupal, como pequenos, mĂ©dios e grandes foram dispostos em gaiolas plĂĄsticas, (10 x 15cm), alimentados com dieta artificial e ĂĄgua estĂ©ril. Foram formadas 15 gaiolas com um casal cada, todos de tamanho mĂ©dio, cinco gaiolas com 3 casais de tamanho pequeno e mĂ©dio e 4 com trĂȘs casais de tamanho grande. O nĂșmero mĂ©dio de cĂłpulas dos casais de tamanho mĂ©dio mantidos individualmente (1,13) foi significativamente menor do que o dos insetos pequenos (2,58), mĂ©dios (2,47) e grandes (2,33),mantidos a trĂȘs por gaiola. A fecundidade mĂ©dia dos casais individuais (1.398,00) tambĂ©m foi significativamente menor que a dos mantidos a trĂȘs por gaiola, tanto de tamanho pequeno (1.709,07), mĂ©dio (2.044,27) e grande (2.469,92). Entre estes Ășltimos observou-se efeito positivo entre o tamanho da pupa e a fecundidade, com diferenças significativas entre todos os tamanhos. A fertilidade mĂ©dia dos casais individuais (67,45) foi muito inferior a observada para os casais pequenos (97,32%), mĂ©dios (96,43%) e grandes (98,91%), mantidos a trĂȘs por gaiola. Estes resultados indicam que em estudos que estimam o potencial reprodutivo devem ser utilizados pelo menos trĂȘs casais por gaiola e que sejam descritos os pesos das pupas que originaram os adultos
Parùmetros biológicos dos estågios imaturos de Spodoptera eridania (Stoll, 1782) (Lepidoptera: Noctuidae), em condiçÔes controladas.
O gĂȘnero Spodoptera (GuenĂ©e, 1852) Ă© cosmopolita e abriga grande parte das lagartas de importĂąncia agrĂcola. Spodoptera eridania (Stoll, 1782) Ă© uma espĂ©cie polĂfaga que se alimenta de plantas de 57 famĂlias, incluindo muitas de importĂąncia econĂŽmica. Este estudo objetivou detalhar parĂąmetros biolĂłgicos de desenvolvimento dos estĂĄgios imaturos de S. eridania, em condiçÔes controladas (25 ± 1ÂșC, 70 ± 10% UR e fotofase de 14 horas). Foram avaliados 4.454 ovos provenientes de 16 posturas e 298 larvas neonatas, individualmente, alimentadas com dieta artificial modificada de Grenee et al. A viabilidade dos ovos, larvas, prĂ©-pupas e pupas foi de 97,82; 93,62; 96,42; 97,03%, com duração de 4,00; 16,18; 1,58 e 9,17 dias, respectivamente. Observou-se que 93% das fĂȘmeas e 100% dos machos passaram por seis e 7% das fĂȘmeas passaram por sete instares larvais. A partir do quinto Ănstar observou-se diferenciação no tamanho das cĂĄpsulas entre machos e fĂȘmeas de seis instares e, entre fĂȘmeas com as de sete instares, a diferenciação iniciou no quarto Ănstar, com razĂŁo de crescimento menor que as demais, no entanto o tamanho final foi maior que nas larvas de seis instares, compensado pelo Ănstar adicional. O tamanho final das cĂĄpsulas foi significativamente diferente entre fĂȘmeas (2,64mm) e machos (2,50mm), bem como entre as fĂȘmeas que passaram por seis (2,64mm) e sete Ănstares (2,72mm). Nas larvas femininas e masculinas de seis instares a razĂŁo mĂ©dia de crescimento foi de 1,52 e 1,51, respectivamente; nas de sete Ănstares foi de 1,44. As pupas femininas das larvas que passaram por seis instares foram significativamente maiores (377,53mg) do que os machos (329,45mg), porĂ©m, menores que as provenientes de larvas que passaram por sete Ănstares (435,11mg). Tanto a metodologia de criação quanto a dieta larval foram adequadas, pois permitiram 85,87% de sobrevivĂȘncia e um detalhamento muito maior das observaçÔes, especialmente, quando larvas
Detecting structural variances of Co_3O_4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope
This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co_3O_4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below ~100 e/Ă
^2s are used and the contrast required for detection of single atoms is generated by capturing large image series. Threshold doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co_3O_4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. An exposure of the Co_3O_4 spinel structure to water vapor or other gases induces drastic structure alterations that can be captured in this manner
Generalized Involution Models for Wreath Products
We prove that if a finite group has a generalized involution model, as
defined by Bump and Ginzburg, then the wreath product also has a
generalized involution model. This extends the work of Baddeley concerning
involution models for wreath products. As an application, we construct a
Gelfand model for wreath products of the form with abelian, and
give an alternate proof of a recent result due to Adin, Postnikov, and Roichman
describing a particularly elegant Gelfand model for the wreath product \ZZ_r
\wr S_n. We conclude by discussing some notable properties of this
representation and its decomposition into irreducible constituents, proving a
conjecture of Adin, Roichman, and Postnikov's.Comment: 29 page
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