bluuebunny/crossref_metadata_2025 huggingface dataset:
A construção de uma teoria de ensembles: antecedentes em Maxwell e Boltzmann
Authors: Laranjeiras Cássio C. , Chiappin José R.N.
Published: May 2009

O objetivo deste artigo é investigar no trabalho de James C. Maxwell (1831-79) e Ludwig Boltzmann (1844-1906) as bases da construção daquilo que modernamente, após Willard Gibbs (1839-1903), ficou conhecido como uma teoria de ensembles, uma abordagem metodológica que alimentou a busca por uma fundamentação estatística para as leis da termodinâmica.
La historia del concepto de fuerza electromotriz en circuitos eléctricos y la elección de indicadores de aprendizaje comprensivo
Authors: Guisasola Jenaro , Montero Antonio , Fernández Manuel
Published: May 2009

En este trabajo consideramos la historia de la ciencia en la enseñanza de las ciencias como un instrumento útil para identificar dónde estuvieron los problemas en la construcción de los conceptos y teorías, indicando qué barreras epistemológicas hubieron de superarse y las ideas que permitieron avanzar. Desde este punto de vista hemos elaborado un marco conceptual para el concepto de fuerza electromotriz. Posteriormente hemos formulado 'indicadores de aprendizaje' que indican los diferentes estadios que se deben trabajar en una secuencia de enseñanza y que establecen los principales conceptos y formas de razonamiento que deben aprender los estudiantes. Mostramos que, en el caso del concepto de fuerza electromotriz, el conocimiento de las dificultades históricas y de las ideas que contribuyeron a superarlas nos proporcionan una información útil para diseñar secuencias de enseñanza y objetivos de aprendizaje bien fundamentados.
A formulação dos 'estados relativos' da teoria quântica
Authors: Freitas Fábio , Freire Jr. Olival
Published: May 2009

O objetivo desse artigo é uma apresentação didática, em português, da interpretação dos estados relativos, publicada por Hugh Everett em 1957. Nessa apresentação, reescrevemos os argumentos originais utilizando o formalismo de Dirac de modo a simplificar sua compreensão. A apresentação foi feita sem o uso de cargas ontológicas posteriores, seguindo principalmente os textos originais de Everett. Ao longo dos tópicos, evidenciaremos quais os principais problemas enfrentados por essa interpretação.
La unificación de luz, electricidad y magnetismo: la "síntesis electromagnética" de Maxwell
Authors: Beléndez Augusto
Published: May 2009

A comienzos del siglo XIX la luz, la electricidad y el magnetismo eran considerados tres fenómenos independientes. Mientras que el interés por la óptica estaba justificado por su aplicación a la construcción de instrumentos ópticos, los fenómenos eléctricos y magnéticos podían resultar interesantes para los científicos, pero carecían de trascendencia al no haber dado lugar a aplicaciones prácticas. En este trabajo, y tras una breve descripción de la situación de la electricidad, el magnetismo y la óptica a comienzos del siglo XIX, se presenta la unificación de la electricidad y el magnetismo con figuras como Oersted, Ampère y Faraday, y se concluye con la "síntesis de Maxwell" de la electricidad, el magnetismo y la luz, de tanta relevancia como en su día fue "la síntesis newtoniana" de la física de los cielos y la física terrestre. Esta "síntesis de Maxwell" constituye uno de los mayores logros de la física, pues no solamente unificó los fenómenos eléctricos y magnéticos, sino que permitió desarrollar toda la teoría de las ondas electromagnéticas, incluyendo la luz. A partir de Maxwell, otra parcela de la física hasta entonces independiente, la óptica, quedó en cierta medida englobada en el electromagnetismo.
Efectos de la inserción de elementos de parámetros concentrados sobre los modos normales de oscilación de un medio finito continuo
Authors: Gómez B.J. , Repetto C.E. , Stia C.R. , Welti R.
Published: May 2009

En este trabajo se estudia la influencia de parámetros concentrados sobre los modos normales de oscilación de un medio continuo de dimensiones finitas. En particular, se estudian las vibraciones de una antena dipolo corta con una inductancia concentrada y los modos acústicos en un tubo con una cámara de expansión en su punto medio. Se encuentra que estos problemas presentan una gran similitud con los modos transversales de una cuerda homogénea, fija en sus dos extremos y cargada con una masa en su punto medio.
A comunicação como barreira à inclusão de alunos com deficiência visual em aulas de óptica
Authors: Camargo Eder Pires de , Nardi Roberto , Veraszto Estéfano Vizconde
Published: May 2009

O presente artigo representa uma continuidade dos resultados apresentados em Camargo e Nardi (Revista Brasileira de Ensino de Física 29, 117 (2007)). Encontra-se inserido dentro de um estudo que busca compreender as principais barreiras para a inclusão de alunos com deficiência visual no contexto do ensino de física. Focalizando aulas de óptica, analisa as dificuldades comunicacionais entre licenciandos e discentes com deficiência visual. Para tal, enfatiza as estruturas empírica e semântico-sensorial das linguagens utilizadas, indicando fatores geradores de dificuldades de acessibilidade nas informações veiculadas. Recomenda, ainda, alternativas que visam dar condições à participação efetiva do discente com deficiência visual no processo comunicativo, das quais destacam-se: a identificação da estrutura semântico-sensorial dos significados veiculados, o conhecimento da história visual do aluno, a destituição da estrutura empírica audiovisual interdependente e a exploração das potencialidades comunicacionais das linguagens constituídas de estruturas empíricas de acesso visualmente independente. Conclui afirmando que a comunicação representa a principal barreira à participação efetiva de alunos com deficiência visual em aulas de óptica e enfatiza a importância da criação de canais comunicacionais adequados como condição básica à inclusão desses alunos.
A física de partículas elementares e o Prêmio Nobel de física 2008
Authors: Pleitez V.
Published: May 2009

O prêmio Nobel de física de 2008 homenageou três físicos teóricos por seus trabalhos relacioandos com simetrias da natureza. Apresentamos uma breve resenha sobre a importância desses trabalhos e o contexto em que foram realizados.
Abordando a dinâmica de fluidos por uma via intuitiva, embora de validade restrita: princípio da superposição
Authors: Ramalho Marcus V.C. , Santos Marcus B.L.
Published: May 2009

O princípio da superposição é invocado de maneira ampla na física, mas o estudante deve ter em mente que sua validade limita-se às situações regidas por equações lineares. Tal é o caso do eletromagnetismo, em contraste com a dinâmica de fluidos. Nesta ultima, as equações são em geral não-lineares, podendo contudo se reduzir a equações lineares num caso particular de grande interesse, capaz inclusive de abranger situações dependentes do tempo. O objetivo desse artigo de cunho pedagógico é explorar as analogias deste caso com o eletromagnetismo, de forma a possibilitar uma introdução rápida à dinâmica de fluidos por parte do estudante não familiarizado com este ramo fascinante porém geralmente ausente da formação do físico. Nesse processo daremos ênfase ao traçado de linhas de corrente mediante o uso de ferramentas gráficas computacionais que, acreditamos, facilitarão ao estudante a percepção da analogia mencionada.
Construcción y caracterización de un tubo Ranque-Hilsch
Authors: García Contreras O.J. , Muñoz Bravo Jorge E. , Fajardo F.
Published: May 2009

El fenómeno de distribución de temperatura en un flujo de gas rotante es conocido como el efecto Ranque-Hilsch. El tubo Ranque-Hilsch (R-H) es un sistema que en ausencia de partes móviles separa un flujo de aire en dos porciones, fría y caliente. En este trabajo un tubo R-H es construido utilizando piezas de bajo costo. Nosotros mostramos el efecto que tiene variar algunos de sus parámetros como: la longitud del tubo, el diámetro de salida de aire frío y el diámetro de una válvula cilíndrica en el gradiente de temperatura generado en los extremos. Como resultado se obtiene una configuración del tubo que optimiza la diferencia de temperatura del flujo. El tubo R-H es construido con materiales de bajo costo y fáciles de conseguir, lo cual facilita su montaje para ilustrar fenómenos de fluidos en los laboratorios de mecánica de fluidos y termodinámica en las carreras de ingeniería y física.
A física nas séries iniciais (2ª a 5ª) do ensino fundamental: desenvolvimento e aplicação de um programa visando a qualificação de professores
Authors: Damasio Felipe , Steffani Maria Helena
Published: May 2009

Neste trabalho descrevemos uma proposta para melhorar o ensino de física nas séries do ensino fundamental. Com este objetivo foi desenvolvido um programa que visa qualificar professores. O programa é estruturado em módulos, que contemplam diversos instrumentos e estratégias pedagógicas. Cada módulo começa com aulas de laboratório, seguido de uma interação em sala de aula com textos que abordam história da ciência, física do cotidiano e discussão de conceitos físicos. Por fim, cada módulo utiliza recursos multimídia, disponíveis na internet. O programa foi aplicado em curso de extensão da UFRGS para doze professoras do Colégio São Bento, em Criciúma, SC, e em minicurso no II Encontro Estadual de Ensino de Física no Instituto de Física da UFRGS. As professoras do Colégio São Bento aplicaram os conteúdos de física aos alunos das séries iniciais do ensino fundamental através de oficinas intituladas "Física para Crianças" e fizeram adaptações, quando necessárias, para adequar os conteúdos e estratégias aos interesses e características dos estudantes.
Espectroscopia de impedância no laboratório de ensino
Authors: Chinaglia D.L. , Gozzi G. , Alfaro R.A.M. , Hessel R.
Published: May 2009

Neste trabalho, mostramos que uma configuração desconhecida de um circuito montado com resistores e capacitores no interior de uma "caixa preta", pode ser determinada através de uma técnica, conhecida como espectroscopia de impedância, largamente utilizada em várias areas da ciência. Como essa técnica faz uso da impedância complexa, apresentamos também uma introdução aos circuitos AC do ponto de vista do formalismo de números complexos. O arranjo experimental utiliza um gerador de audio como fonte AC para alimentar a caixa e um osciloscópio de duplo canal para medir tanto a parte real como a imaginária da impedância complexa do circuito desconhecido em função da frequência do gerador. A partir do espectro de impedância obtido, identifica-se não só a configuração do circuito no interior da caixa como também os valores das resistências e capacitâncias utilizadas para montá-lo.
Equipamentos interativos: uma contribuição dos centros e museus de ciências contemporâneos para a educação científica formal
Authors: Chinelli Maura Ventura , Pereira Grazielle Rodrigues , Aguiar Luiz Edmundo Vargas de
Published: May 2009

Este artigo descreve um processo de pesquisa que buscou encontrar, nos centros e museus de ciências, contribuições para a educação científica formal. Foi realizado na forma de pesquisa-ação com a participação, como pesquisadores, de 10 (dez) estudantes de cursos de Licenciatura (em física, química e matemática) que procuraram identificar, nos equipamentos interativos disponíveis nesses espaços, aqueles que permitissem a realização de experimentos e pudessem ser reproduzidos nas escolas. Os resultados são discutidos em relação à presença dos diferentes campos do conhecimento nos museus e centros de ciências (cerca de 80% desses experimentos são de física) e a forma como os equipamentos interativos lá existentes podem ser usados como recursos para a educação formal em ciências. Como conclusão, tem-se que esses equipamentos ultrapassam o papel de experimentos de baixo custo para escolas sem laboratórios, possibilitando experimentos estimulantes que trazem aos alunos a satisfação de encontrar respostas para questões que os intrigam.
A rotação estelar e seu efeito sobre os espectros
Authors: Levenhagen R.S. , Künzel R.
Published: May 2009

Esta nota tem por objetivo tratar da determinação da taxa de rotação do Sol e outras estrelas. Após uma breve introdução histórica, é descrito o método da transformada de Fourier (TF) aplicada ao estudos dos perfis espectroscópicos, e discutidos os efeitos da rotação estelar sobre a forma dos perfis de linhas espectrais.
Interação forte e eletromagnetismo
Authors: Silva P.R.
Published: May 2009

A interação nuclear forte é estudada através de algumas ferramentas do eletromagnetismo clássico. São estimadas a constante de acoplamento forte e o "campo elétrico forte" (em termos de um campo elétrico equivalente), no interior do núcleon (próton ou nêutron). A pressão do vácuo sobre a fronteira do núcleon é também avaliada. Discute-se brevemente o confinamento dos quarks. Na análise são ainda utilizadas versões simplificadas do modelo de sacola do MIT.
Simulação e modelagem computacionais no auxílio à aprendizagem significativa de conceitos básicos de eletricidade. Parte II: circuitos RLC
Authors: Dorneles Pedro F.T. , Araujo Ives S. , Veit Eliane A.
Published: May 2009

Neste artigo analisamos o comportamento da energia eletromagnética em circuitos do tipo RLC. Discutimos as principais dificuldades dos alunos na aprendizagem de conceitos básicos envolvidos neste tipo de circuito e apresentamos dois produtos oriundos de um trabalho de pesquisa: i) um conjunto de atividades de simulação e modelagem computacionais, propostas com o software Modellus, levando em conta tais dificuldades, com o objetivo de auxiliar o aluno a superá-las e ii) um teste sobre a compreensão de conceitos físicos envolvidos em circuitos RLC.
Um esboço da história do conceito de trabalho virtual e suas aplicações
Authors: Cindra José Lourenço
Published: May 2009

Neste trabalho abordamos a questão concernente à origem do princípio de trabalho virtual e sua consolidação como um dos conceitos fundamentais no estudo da mecânica analítica e, em particular, dos sistemas em equilíbrio estático. Ênfase foi dada às contribuições seminais de Stevin, Galileu e, sobretudo, as de d'Alembert e Lagrange, no tocante ao conceito de trabalho virtual. Além disso, faz-se um comentário geral sobre vínculos holônomos e deslocamento virtual. Alguns exemplos de emprego da equação de d'Alembert-Lagrange são apresentados, para mostrar como o princípio de trabalho virtual pode ser adequadamente aplicado.
Mitochondrial DNA Differentiation Between Two Closely Related Species, Phlebotomus (Paraphlebotomus) chabaudi and Phlebotomus (Paraphlebotomus) riouxi (Diptera: Psychodidae), Based on Direct Sequencing and Polymerase Chain Reaction-Restriction Fragment Length Polymorphism
Authors: Boudabous Raja , Bounamous Azzedine , Jouet Damien , Depaquit Jérôme , Augot Denis , Ferté Hubert , Berchi Sélima , Couloux Arnaud , Veuille Michel , Babba Hamouda
Published: May 2009

Phlebotomus chabaudi Croset, Abonnenc & Rioux, 1970 and Phlebotomus riouxiDepaquit, Killick-Kendrick & Léger, 1998 (Diptera: Psychodidae) are closely related species of phlebotomine sand flies, the females of which are suspected of transmitting Leishmania killicki Rioux, Lanotte, and Pratlong 1986 in Tunisia. Although males of these species are distinguishable by the number and size of setae on the basal lobe of the coxite, morphologically differential characters between the females are blurred. A molecular study, based on 40 Algerian and Tunisian specimens, was conducted to distinguish females of these two species. Alignment of the cytochrome c oxidase I (COI) sequences and their analysis by using neighbor-joining and maximum likelihood showed the separation of P. chabaudi and P. riouxi, irrespective of intraspecific variability. Both COI and cytochrome b have been tested as molecular identification tools. Single strand conformation polymorphism analysis did not distinguish these two species, whereas restriction fragment length polymorphism can be applied to identify P. chabaudi and P. riouxi for surveillance purposes.
Molecular Phylogeny of Stigmaeopsis, With Special Reference to Speciation Through Host Plant Shift
Authors: Sakagami Takane , Saito Yutaka , Kongchuensin Manita , Sahara Ken
Published: May 2009

Similar nest-weaving habits and sociality characterize all the species belonging to the recently reinstated spider mite genus Stigmaeopsis. Molecular phylogenetic analysis using 28S rDNA shows that Stigmaeopsis forms a distinct clade and that there is another unrecognized clade involving Schizotetranychus species with comparable nest-weaving habits distributing in tropical regions. Furthermore, the phylogenic hypothesis suggests that Stigmaeopsis miscanthi (Saito) inhabiting Miscanthus sinensis Anderss. shared a common ancestor with Stigmaeopsis longus (Saito) inhabiting Sasa senanensis (Franch. et Sav.), both mite species having very similar social systems. We confirmed reproductive isolation between them and tested the suitability of the two plant species as hosts for these two mite species. The result that S. miscanthi immatures could survive on Sasa bamboo for a long period, but S. longus immatures could not survive on Miscanthus grass suggested that the former has evolved from a common ancestor living on Sasa bamboo. This is also supported by a third piece of indirect evidence obtained from observing mite responses to the plant-originated chemical cues involving feces used for waste management in these species. Therefore, we conclude that the host plant shift of S. miscanthi from Sasa bamboo to M. sinensis played a key role in speciation.
The Field Cricket Gryllus assimilis and Two New Sister Species (Orthoptera: Gryllidae)
Authors: Weissman David B , Walker Thomas J , Gray David A
Published: May 2009

In preparation for revisionary studies of western U.S. Gryllus field crickets, some eastern U.S. names for species with supposed transcontinental distributions must be resolved. One such species, Gryllus assimilis (F.), as currently characterized, occurs in the West Indies, Brazil, Central America, and Mexico, and in five of the southernmost U.S. states. Our studies of calling songs and morphology indicate that at least three species exist among these populations. The type locality of G. assimilis is Jamaica, but the type specimen is lost and two similar species of Gryllus occur there. One of these species occurs widely outside of Jamaica, and we assign it to G. assimilis and designate a neotype. The other occurs only in Jamaica and is assigned to Gryllus jamaicensis T. J. Walker n. sp. Nearly all populations formerly known as G. assimilis from southern California, southern Arizona, southern Nevada, and Mexico west of the continental divide are assigned to Gryllus multipulsator Weissman n. sp. Populations located elsewhere (with one exception) are deemed conspecific with Jamaican G. assimilis, although G. assimilis from islands east and south of Hispaniola have calling songs with dominant frequencies higher than is characteristic of the species elsewhere. Studies of mitochondrial DNA of assimilis-type Gryllus from widespread localities are compatible with the above species classification. Hybridization trials between G. assimilis and G. multipulsator demonstrated high interfertility. Gryllus contingent F. Walker and Gryllus mundus F. Walker are removed from synonymy with G. assimilis.
Insights Into Flea Beetle (Coleoptera: Chrysomelidae: Galerucinae) Host Specificity From Concordant Mitochondrial and Nuclear DNA Phylogenies
Authors: Jenkins Tracie M , Kris Braman S , Chen Zhenbang , Eaton Tyler D , Pettis Gretchen V , Boyd David W
Published: May 2009

Flea beetles in the genus Altica are herbivorous, urban agricultural pests that are morphologically difficult to distinguish. Host plant associations, therefore, have been used as an important species character in field studies. Indigenous weeds in the Onagraceae, genus Oenothera, are known to serve as developmental hosts for the flea beetle Altica litigata Fall. Although host plant specificity in herbivorous beetles is labile and adult A. litigata have been reported to aggregately feed on plants in the nonindigenous Lythraceae, genus Lagerstroemia, there is no evidence that these ornamental trees serve as developmental hosts. Because adult A. litigata feed on host plants from species in two plant genera, this study was designed to test two hypotheses. The first hypothesis that was tested was whether adult flea beetles collected from primrose and crape myrtle plants across four ecoregions are phenotypically (morphology) and genotypically (genotype) A. litigata. The second hypothesis that was tested was whether two unlinked loci, cytochrome oxidase subunit I and internal transcribed spacer, are phylogenetically concordant for flea beetle species. If so, they could be used to determine the intraspecific geographic history of A. litigata collected from Oenothera and Lagerstroemia species. We discuss how these markers, in conjunction with morphology and host plant feeding behavior, can not only help to validate morphologically difficult taxa but also can illuminate herbivore-plant genetic structure through phylogeny analyses.
Assessments of Fitness Effects by the Facultative Symbiont Rickettsia in the Sweetpotato Whitefly (Hemiptera: Aleyrodidae)
Authors: Chiel Elad , Inbar Moshe , Mozes-Daube Netta , White Jennifer A , Hunter Martha S , Zchori-Fein Einat
Published: May 2009

The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), harbors several bacterial symbionts, including the obligate primary symbiont Portiera aleyrodidarum and the facultative secondary symbionts Arsenophonus, Cardinium, Fritschea, Hamiltonella, Rickettsia, and Wolbachia. The roles of these symbionts are yet unknown. In this study, we tested for possible effects of one symbiont, Rickettsia, on some fitness parameters of B. tabaci (biotype B) by comparing whiteflies that carry this symbiont to whiteflies that do not. Preadult development of Rickettsiacarrying whiteflies was faster, but all the other parameters that were measured: longevity, total number of progeny, sex ratio, and nymphal survivorship did not differ significantly. Estimates of the intrinsic growth rate (r) were almost identical for the two groups. Cross-mating between clefts-carrying and Rickettsia-free whiteflies provided no evidence for cytoplasmic incompatibility. Vertical transmission of Rickettsia was found to be nearly complete. Our results do not clearly identify a selective advantage that would explain the high prevalence of Rickettsia in B. tabaci populations, thus, other fitness parameters and horizontal transmission routes are suggested and discussed.
Co-Occurrence of the Invasive Banded and European Elm Bark Beetles (Coleoptera: Scolytidae) in North America
Authors: Lee Jana C , Aguayo Ingrid , Aslin Ray , Durham Gail , Hamud Shakeer M , Moltzan Bruce D , Munson A Steve , Negrón José F , Peterson Travis , Ragenovich Iral R , Witcosky Jeffrey J , Seybold Steven J
Published: May 2009

The invasive European elm bark beetle, Scolytus multistriatus (Marsham), was detected in Massachusetts a century ago, and it now occurs throughout the continental United States and southern Canada. The Asian banded elm bark beetle, Scolytus schevyrewi Semenov, was discovered in the United States in 2003, and now occurs in 28 states and the province of Alberta, Canada. Although the indigenous populations of these two species are allopatric, the invasive populations are now sympatric in North America where they co-colonize elm (Ulmus spp.) trees. A large-scale survey of these two Scolytus species was conducted with baited funnel traps, Plexiglas panel traps, and Ulmus pumila L. trap logs. Sites (four per locality) were monitored around Sacramento, CA; Reno, NV; Ogden, UT; Newcastle, WY; and Fort Collins, CO (2006–2007), and Manhattan, KS, and Columbia, MO (both only in 2007). Trap catches of S. schevrewyi relative to both Scolytus species captured from all three trapping methods at each survey site were 90 and 89% in Colorado, 90 and 83% in Wyoming, 60 and 68% in Utah, 43 and 68% in Nevada, and 11 and 13% in California (all in 2006 and 2007, respectively), and 3.3% in Kansas and 2.7% in Missouri (both only in 2007). Elevated abundances of S. schevyrewi at survey sites in Colorado and Wyoming could be the result of competitive displacement of S. multistriatus by S. schevyrewi, whose occurrence and mechanism require further study. General seasonal trends from all sites indicated peak flight in July and August for S. schevyrewi and two peaks (May-June and July-August) for S. multistriatus. Funnel traps baited with Multilure and 2-methyl-3-buten-2-ol were highly attractive to S. multistriatus, and mildly attractive to S. schevyrewi, whereas panel traps caught few beetles. The U. pumila trap logs were a more sensitive monitoring tool for detecting the presence of S. schevyrewi.
Reproduction, Longevity, and Survival of Cactoblastis cactorum (Lepidoptera: Pyralidae)
Authors: Legaspi Jesusa Crisostomo , Baez Ignacio , Legaspi Benjamin C.
Published: May 2009

Screened potted cactus, Opuntia ficus-indica (L.) Mill., plants containing pairs of adult male and female cactus moths, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), were placed in a cactus field in St. Marks, FL, to measure oviposition patterns under ambient conditions. Results showed a narrow window for oviposition during third and sixth day of adult female's life. Peak oviposition activity occurred on the third day, whether measured in total fecundity, numbers of eggs per egg stick or numbers of ovipositions. After the third day, not only did oviposition rate decrease but also the quality of eggs produced declined. Percentage of egg hatch decreased and egg incubation increased. Longevity of adult males (6.3 ± 0.79 d) did not differ from that of females (5.2 ± 0.4), although female adults (157.8 ± 4.5 mg) weighed more than males (74.9 ± 1.51). Therefore, from the perspective of mass rearing this moth, the optimal time for collecting eggs is limited to the third day in the life of the adult female.
Effect of Host Plant on Biology and Life Table Parameters of Brevicoryne brassicae (Hemiptera: Aphididae)
Authors: Mirmohammadi Shirin , Allahyari Hussein , Nematollahi Mohammad Reza , Saboori Alireza
Published: May 2009

The cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae), is a key pest of oilseed rape, Brassica napus L., and produces economic damage. Commonly, life table parameters have been used to compare insect fitness on different varieties. Effects of four different varieties of oilseed rape (‘Zarfam’, ‘Licord’, ‘Hyola 401’, and ‘SLM046’) on biological aspects and fecundity life table parameters of B. brassicae were studied under laboratory conditions. There was no significant difference between the length of prereproductive, reproductive, postreproductive periods, and fecundity of aphid developing on different varieties. The maximum length of prereproductive, reproductive, and longevity periods of B. brassicae were observed in the Licord variety. The maximum fecundity of aphid was recorded on Hyola 401. The intrinsic rate of increase was estimated by using Euler-Lotka equation and was compared with those estimated using Wyatt and White's equation. Intrinsic rate of increase of B. brassicae (based on jackknife method) was 0.298, 0.294, 0.311, and 0.289 on Zarfam, Licord, Hyola 401, and SLM046, respectively. Feeding on SLM046 and Licord reduced the reproductive capacity of the cabbage aphid compared with the other varieties studied. However, statistical analysis of Wyatt and White output showed that calculated rm were higher than that Euler-Lotka equation and there was not significant difference between rm on different varieties. Aphid population growth 20 d after plant infestation showed no significant difference between numbers of produced aphids, but significant difference in the number of winged aphids.
Delayed Larval Development Without Summer Diapause in a Galling Adelgid (Hemiptera: Adelgidae)
Authors: Tabuchi K , Sano M , Ozaki K
Published: May 2009

To elucidate how galling adelgids (Hemiptera: Adelgidae) vary their larval (=galling) periods between species, we compared larval development of Adelges japonicus (Monzen) to that of Adelges pectinatae (Cholodkovsky) on Picea jezoensis (Siebold & Zucc.) Carr. (Pinaceae). Although eggs of the two species hatch when new buds begin to burst in spring, A. japonicus has a much longer larval period (≈3 mo) than A. pectinatae (≈1 mo). Larvae of A. pectinatae developed rapidly in every stadium and completed their growth by mid-June. In contrast, larvae of A. japonicus developed slowly through each stadium and became the last instar between early August and early September. There was no instar with particularly long developmental period. Despite the larval period difference, percentage of each instar period differed little between the two species, indicating that the longer larval period in A. japonicus is not caused by summer diapause in a specific instar. Nitrogen contents in galls of the two species were highest at budburst and declined rapidly until late June. A. japonicus larvae stayed as first instar when nitrogen contents in galls were high. In addition, nitrogen contents in galls were always higher for A. japonicus than for A. pectinatae, suggesting that delayed development in A. japonicus larvae is not a result of nutrient limitation, but is a naturally programmed response to pass the summer in larval stage and wait for autumn to become adults. This study is the first to clearly show that insects reduce their development in each stadium to prolong their larval period in summer.
Hypoxia Tolerance in Adult and Larval Cicindela Tiger Beetles Varies by Life History but Not Habitat Association
Authors: Brust Mathew L , Hoback W Wyatt
Published: May 2009

Flooding exposes terrestrial organisms to severe hypoxia. Among the best- studied insects that are frequently exposed to flooding are tiger beetle (Coleoptera: Cicindelidae) larvae. In previous studies with a limited number of species, a correlation was found between habitat and hypoxia tolerance. In the current study, we examined hypoxia tolerance among third instars of six Cicindela species that vary in habitat association; we also tested adult survival of these species. We found that larvae of the different species survived an average of between 60 and 120 h of submersion in severely hypoxic water at 20°C, with larvae that occur in dry sand having somewhat lower survival times. However, among larvae, there was no correlation between survival times and habitat risk of flooding. We found surprisingly high survival times among adult tiger beetles with a range of 10 h to 46 h. Adult Cicindela formosa formosa Say that are associated with dry sand and are active in the spring and fall survived submersion for >40 h, longer than any previously reported adult terrestrial insect exposed to hypoxia at moderate environmental temperatures. The lengthy survival times of adult tiger beetles are likely a result of adaptations to immersion during periods of inactivity. Our study suggests that additional insect species and life stages should be examined for hypoxia tolerance regardless of perceived threat of immersion.
Relationships Between Adult Abdominal Color and Reproductive Potential in Diaphorina citri (Hemiptera: Psyllidae)
Authors: Wenninger Erik J , Stelinski Lukasz L , Hall David G
Published: May 2009

Diaphorina citri Kuwayama (Hemiptera: Psyllidae), a vector of huanglongbing (citrus greening disease), exhibits three more or less distinct abdominal colors in the adult stage: gray/brown, blue/green, and orange/yellow. A previous report showed that, relative to blue/green individuals, gray/brown individuals of both sexes have lower body mass, and gray/brown females may have lower reproductive output. In the present investigation, we directly examined the relationships between female and male abdominal color and reproductive output. We also assessed how psyllid body mass was influenced by transfer to fresh plant material and how female and male abdominal color affected behavioral responses of males to crushed females in a petri dish assay. Relative to blue/green females, gray/brown females exhibited lower fecundity over the first 2–5 d after mating, but fecundity did not differ over the remainder of a 21-d observation period. Regardless of abdominal color, females mated with gray/brown males showed an earlier, sharper peak in fecundity, whereas females mated with blue/green males showed a later, more gradual peak in fecundity. Gray/brown males elicited lower egg fertility in their mates, but egg fertility did not vary according to female abdominal color. Males—irrespective of abdominal color—exhibited stronger evidence of attraction to crushed blue/ green females than to crushed gray/brown females. Gray/brown individuals of both sexes showed an increase in body mass 5–6 d after transfer to a new citrus seedling, suggesting that abdominal color (which is closely related to body mass) may be influenced at least in part by plant quality.
Sequential Florivory/Saproflorivory of Anaxagorea crassipetala (Annonaceae) by Diathoneura tessellata (Drosophilidae)
Authors: Collier G E , Armstrong J E
Published: May 2009

Diathoneura tessellata Duda, 1925 (Diptera: Drosophilidae) uniquely and effectively uses the fleshy tepals of Anaxagorea crassipetala (Annonaceae), a small, understory tree of the primary lowland rain forest of Costa Rica, as a larval substrate and pupation site. This study is the first to document 1) the brood substrate for larvae of this species and the 2) use of flowers in the Annonaceae as a drosophilid larval substrate. Oviposition into the tough, immature flower buds is made possible by an enlarged oviscape. This relationship is unique in that these flowers support two sequential cohorts of larvae, one cohort mining the living tepals of immature and mature flowers and the second cohort consuming the fallen, postanthesis tepals. We refer to this phenomenon as sequential florivory/saproflorivory. The first cohort consists of fewer, larger larvae, whereas the second cohort consists of more numerous, smaller larvae. Both cohorts exhibit a female skewed sex ratio.
Allozyme Variation in Hemlock Woolly Adelgid (Hemiptera: Adelgidae) From the United States and China
Authors: Sánchez V , Keena M A
Published: May 2009

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is a major introduced pest of eastern hemlock, Tsuga canadensis (L.) Carrière. Hemlock woolly adelgid in the United States is anholocyclic and an obligate parthenogen, because no suitable primary host (on which sexual reproduction occurs in Asia) is reported for this adelgid in the United States. Allozyme analyses were conducted to assess the relatedness between three hemlock woolly adelgid populations in the eastern United States (Connecticut, New Jersey, and Virginia) and to compare them with adelgids from the western United States (Washington) and China. Significant hemlock woolly adelgid allozyme variation was found between nonadjacent trees within a site in the eastern United States. There was a small difference between the two northern and the southern populations despite the relative genetic uniformity between the sites across the allozyme loci evaluated. There were low numbers of protein alleles in the eastern populations, whereas the western and Chinese populations had additional alleles not found in the eastern populations. Both heterozygote excesses and deficits were detected as would be expected in populations that are not randomly mating. There were only a few abundant genotypes and they tended to be more homozygous than the rarer genotypes. The hemlock woolly adelgid population from China that is cyclically parthenogenic was more genetically diverse than the other hemlock woolly adelgid populations that are presumed to be obligately parthenogenic. Allozymes provide some useful information about genetic variation in hemlock woolly adelgid but seem to be less suited to assess actual genetic diversity and structure of populations because of the small size of the hemlock woolly adelgid.
New sources of β-cells for treating diabetes
Authors: Sahu Subhshri , Tosh David , Hardikar Anandwardhan A
Published: May 2009

The treatment of diabetes by islet transplantation is presently hampered by the shortage of organ donors. The generation of insulin-producing cells is therefore a major objective in the long-term goal of curing diabetes. Alternative sources of pancreatic β-cells include existing pancreatic cells, embryonic stem cells, and cells from other tissues such as liver. This commentary considers evidence for two new sources of β-cells: intrahepatic biliary epithelial cells and gall bladder epithelium. These observations raise the possibility that a patient's own cells may be used as a source of insulin-producing cells for cell replacement in diabetes.
Altered gene expression in the brain and ovaries of zebrafish (Danio Rerio) exposed to the aromatase inhibitor fadrozole: Microarray analysis and hypothesis generation
Authors: Villeneuve Daniel L. , Wang Rong-Lin , Bencic David C. , Biales Adam D. , Martinović Dalma , Lazorchak James M. , Toth Gregory , Ankley Gerald T.
Published: May 2009

As part of a research effort examining system-wide responses of the hypothalamic-pituitary-gonadal (HPG) axis in fish to endocrine-active chemicals (EACs) with different modes of action, zebrafish (Danio rerio) were exposed to 25 or 100 μg/L of the aromatase inhibitor fadrozole for 24, 48, or 96 h. Global transcriptional response in brain and ovarian tissue of fish exposed to 25 μg/L of fadrozole was compared to that in control fish using a commercially available, 22,000-gene oligonucleotide microarray. Transcripts altered in brain were functionally linked to differentiation, development, DNA replication, and cell cycle. Additionally, multiple genes associated with the one-carbon pool by folate pathway (KEGG 00670) were significantly up-regulated. Transcripts altered in ovary were functionally linked to cell-cell adhesion, extracellular matrix, vasculogenesis, and development. Promoter motif analysis identified GATA-binding factor 2, Ikaros 2, alcohol dehydrogenase gene regulator 1, myoblast-determining factor, and several heat shock factors as being associated with coexpressed gene clusters that were differentially expressed following exposure to fadrozole. Based on the transcriptional changes observed, it was hypothesized that fadrozole elicits neurodegenerative stress in brain tissue and that fish cope with this stress through proliferation of radial glial cells. Additionally, it was hypothesized that changes of gene expression in the ovary of fadrozole-exposed zebrafish reflect disruption of oocyte maturation and ovulation because of impaired vitellogenesis. These hypotheses and others derived from the microarray results provide a foundation for future studies aimed at understanding responses of the HPG axis to EACs and other chemical stressors.
Friedel-Crafts Alkylation of Mesitylene with tert-Butyl Alcohol over Novel Solid Acid Catalyst UDCaT-5
Authors: Yadav Ganapati D. , Kamble Shashikant B
Published: May 2009

Alkylation of mesitylene with tert-butyl alcohol in the presence of novel mesoporous superacidic catalysts, namely, UDCaT-4, UDCaT-5 and UDCaT-6 was investigated. The catalysts are modified versions of zirconia showing high catalytic activity, stability and reusability in the presence of water as compared to conventional sulfated zirconia. The catalytic activity is in the order: UDCaT-5 (most active) > UDCaT-6 > UDCaT-4 > sulfated zirconia (S-ZrO2) (least active). The synergistic effect of the very high sulfur content present (9% w/w S) and the preservation of the tetragonal phase in UDCaT-5, in comparison with sulfated zirconia (4% w/w S), were responsible for higher catalytic activity. A catalyst ensuring the production of 2-tert-butyl-mesitylene (2-TBMT) with 98% selectivity and 94% conversion of tert-butanol (TBA) was developed under optimum reaction conditions. The formation of products is correlated with the acidity of the catalyst. The reactions were conducted in liquid phase at relatively low reaction temperatures (120150 °C). A systematic investigation of the effects of various operating parameters was accomplished and a mathematical model is developed to describe the reaction pathway and validated with experimental results. The reaction was carried out without using any solvent in order to make the process cleaner and greener. An overall second order kinetic equation was used to fit the experimental data, under the assumption that both mesitylene and tert-butanol are weakly adsorbed. An independent dehydration study of tert-butanol (TBA) was also done.
Great Moderation at the Firm Level? Unconditional vs. Conditional Output Volatility
Authors: Buch Claudia M , Doepke Joerg , Stahn Kerstin
Published: May 2009

We test whether there has been a "Great Moderation" of output volatility at the firm level. The multifactor residual model proposed by Pesaran (2006) is used to isolate the idiosyncratic component of firms' sales growth from macroeconomic developments. This methodology is applied to a balanced panel of about 1,200 German firms covering a 35-year period (1971-2005). Our research has three main findings. First, unconditional firm-level volatility and aggregate output volatility have seen similar downward trends. Second, conditional, idiosyncratic firm-level volatility does not exhibit a downward trend. Third, there is a positive link between growth and volatility at the firm level.
The Default-Prone U.S. Toxic Asset Auction Plan
Authors: Zheng Charles Zhoucheng
Published: May 2009

Applying auction theory to the toxic-asset rescue plan currently released by the United States Treasury Department, this paper demonstrates an equilibrium where moderately poor bidders outbid rich bidders in such auctions. After defeating their rich rivals and acquiring the toxic assets, such bidders will default on government-provided loans whenever the toxic assets turn out to be unsalvageable. An alternative mechanism is discussed.
Chromosome Y Isodicentrics in two Cases with Ambiguous genitalia and Features of Turner Syndrome
Authors: Lungeanu A , Arghir A , Arps S , Cardos G , Dumitriu N , Budisteanu M , Chirieac S , Rodewald A
Published: May 2009

Chromosome Y Isodicentrics in two Cases with Ambiguous genitalia and Features of Turner Syndrome

Karyotype investigations using classical cytogenetics, fluorescencein situhybridization (FISH) and polymerase chain reaction (PCR) techniques were used for the characterization of Y chromosome structural anomalies found in two patients with ambiguous genitalia and features of Turner syndrome. Both exhibited mosaic karyotypes of peripheral blood lymphocytes. The karyotype was 45, X[90]/ 46, X, idic(Y)(p11.3).ish idic(Y) (wcpY+, DXYS130++,SRY++,DYZ3++,DYZ1++, DYS224++)[10] in one case, and the karyotype was 45, X[65]/46, X, idic(Y) (q11).ish idic(Y)(SRY++, RP11-140H23-)[35] in the other case. Derivative Y chromosomes were different in shape and size and positive for the SRY gene, a common underlying element of ambiguous genitalia phenotypes. These results add new information concerning the role of Y chromosome structural abnormalities in sex determination pathway perturbation which are poorly understood, and highlight the importance of the sex chromosomes integrity for a normal sex phenotype development.
Methylenetetrahydrofolate Reductase C677T Polymorphism and Risk of Colorectal Cancer in the Macedonian Population
Authors: Matevska N , Josifovski T , Kapedanovska A , Sterjev Z , Serafimoska Z , Panovski M , Jankulovski N , Petrusevska N , Angelovska B , Petrusevska G , Suturkova L , Dimovski A
Published: May 2009

Methylenetetrahydrofolate Reductase C677T Polymorphism and Risk of Colorectal Cancer in the Macedonian Population

Methylenetetrahydrofolate reductase (MTHFR) regulates the flow of folate groups between DNA synthesis and DNA methylation. A common C677T substitution (Ala222Val) in exon 4 of the MTHFR gene has been linked with the risk of colorectal cancer (CRC). To assess this risk in the Macedonian population, we conducted a case-control study of 413 randomly selected CRC patients and 185 controls without a clinical diagnosis of CRC. We found a statistically significant inverse association between the MTHFR T allele (35.35% for the patients and 41.35% for the controls) and the CRC risk [odds ratio (OR) 0.776; 95% confidence interval (95% CI) 0.603-0.997;p= 0.047). The prevalence of the MTHFR T allele is lower in patients with advanced CRC (Duke' s stage C and D) and with microsatellite instable tumors (MSI+), indicating the inverse association with the CRC aggressiveness and MSI status. This effect seems to be independent of gender, age of onset and localization. We concluded that the MTHFR 677T allele is more likely to have a protective effect on CRC development and progression in the Macedonian population.
Volunteerism, Health, and Civic Engagement among Older Adults
Authors: Gottlieb Benjamin H. , Gillespie Alayna A.
Published: May 2009

En Amérique du Nord, 40 à 50 pour cent des aînés participent activement à titre de bénévoles officiels à la prestation de divers services de santé et de services sociaux. Nous avons passé en revue des études empiriques sur les raisons motivant le bénévolat chez les aînés, ainsi que sur les bienfaits sur le moral et la santé que ces derniers tirent de cette expression d'altruisme. La connaissance de la nature exacte et du nombre d'activités bénévoles nécessaires pour produire ces effets est limitée, et les études n'ont pas encore permis de déterminer les mécanismes behavioristes et psychologiques en cause. Nous proposons que les aînés bénévoles pourraient jouir d'une bonne santé et vivre longtemps parce que, en étant utiles à d'autres, ils ont le sentiment qu'on a besoin d'eux et qu'ils sont appréciés. Nous présentons plusieurs points de vue théoriques sur l'importance du bénévolat au plan du développement personnel, discutons des défis imposés au bénévolat par la génération du baby-boom, et déterminons les priorités futures en matière de recherche.
Varieties of growing skull fractures in childhood
Authors: Goldstein Frank P. , Rosenthal Sheldon A. E. , Garancis John C. , Larson Sanford J. , Brackett Charles E.
Published: May 2009

✓ Clinical examples of three varieties of leptomeningeal cysts secondary to a traumatic dural tear have been discussed. The cysts developed beneath fracture lines and led to erosion of bone and herniation or depression of brain.
Cysts of the sella turcica
Authors: Weber Emil Lee , Vogel F. Stephen , Odom Guy L.
Published: May 2009

✓ In three patients intrasellar cysts were found without epithelial lining but containing thick dark brown fluid. The clinical course and histological findings suggested intermittent hemorrhage and infarction of the adenohypophysis as the probable etiology. The surgical importance of differentiating these lesions from cystic craniopharyngiomas and pituitary adenomas has been stressed in a discussion of the diagnostic characteristics. Wide surgical drainage is recommended as the treatment of choice. Evidence points to a possible relationship of these cysts to the “empty sella syndrome.”
Kyphoscoliosis with paraplegia
Authors: Gortvai Peter , Fairburn Bernard
Published: May 2009

✓ The cases of six patients with spinal curvature associated with paraplegia are presented and used to illustrate the wide variety of related pathological lesions that may cause cord compression. All six patients improved following surgical treatment. Early investigation and surgical treatment are recommended to prevent progressive cord damage.
Experimental use of cultured cerebellar cortical tissue to inhibit the collagenous scar following spinal cord transection
Authors: Kao Chun Ching , Shimizu Yoshifusa , Perkins Lois C. , Freeman L. W.
Published: May 2009

✓ Two types of barrier to axonal regeneration in the spinal cord were found in experimental spinal cord transection in dogs. One was an astroglial scar formed within the spinal cord, and the other a collagenous scar in the gap between proximal and distal stumps. Autogeneous cultured cerebellar cortical slices transplanted into the space produced by cord transection in adult dogs inhibited collagenous scar formation and converted the gap into a spongy structure. The astroglial scar within the spinal cord remained unchanged. Conversely, transplantation of noncultured cortical slices as a control study enhanced formation of the collagenous scar.