bluuebunny/crossref_metadata_2025 huggingface dataset:
Estoque de nutrientes sob diferentes sistemas de uso do solo de Colorado do Oeste-RO
Authors: Magalhães Sulamirtes Suellem de Amorim , Weber Oscarlina Lúcia dos Santos , Santos Carlos Henrique dos , Valadão Franciele Caroline de Assis
Published: November 2012

A substituição da floresta por outro tipo de uso do solo pode levar a perdas significativas na matéria orgânica do solo, alterando sua dinâmica e como consequência alterando as entradas e saídas de nutrientes do sistema. Neste trabalho o objetivo foi avaliar o estoque de nutrientes em diferentes sistemas de uso de solo em Colorado do Oeste-RO. Os sistemas avaliados foram o agroflorestal (teca e cacau), florestal (teca com cinco anos), teca com oito anos, agrossilvopastoril (teca, cacau e pasto) e pastagem tendo a mata nativa como referência. Em cada sistema foram abertas três minitrincheiras, nas quais foram coletadas amostras deformadas e indeformadas nas profundidades de 0 a 5, 5 a 10, 10 a 20 e 20 a 30 cm. Nessas amostras foram determinados os nutrientes: N, P, K, Ca e Mg, a matéria orgânica, a densidade do solo e os teores de argila. Observaram-se diferenças nos estoques de nutrientes no solo entre os sistemas de uso e em profundidade. A concentração de nutrientes foi influenciada pelo sistema de uso do solo. O nutriente mais estocado em todos os sistemas de uso é o Ca, os valores variaram entre 5188,48 e 2912,86 kg ha-1 e o menos estocado o K, com estoques entre 46,22 e 17,33 kg ha-1. O sistema teca com cinco anos foi o sistema que mais se aproximou da mata, quanto ao armazenamento de nutrientes.
Uma nova (?) fórmula para o cálculo de rações
Authors: Torres A. P.
Published: November 2012

Visando a obtenção dum método fácil e rápido para calcular rações para animais, o Autor deduz e apresenta uma fórmula que dará a quantidade dum alimento a ser acrescentada a uma mistura para balanceá-la. Sugere a necessidade de tabelas apropriadas para facilitar o uso da fórmula.
Contribuição para o controle biológico da broca da cana de açúcar
Authors: Gallo Domingos
Published: November 2012

Em 5 meses e 20 dias, obtivemos 4 gerações de Metagonis lylum minense Towns, correspondentes a um total de 662 adultos. O ciclo evolutivo completo, varia de 31 a 51 dias com evolução média de 38 dias a 18,9°C. As porcentagens de parasitismo natural em culturas de cana e de milho foram respectivamente de 23,1 e 37,3%. Libertaram-se 526 moscas, obtendo-se um parasitismo de 48,3% para cana de açúcar e 61,1% no milho. Em 12 meses foram criados em laboratório 10 gerações de Lixophaga diatraeae Towns, num total de 915 adultos. O ciclo evolutivo completo, de emergência a emergência do adulto, varia de 30 a 39 dias nos meses de Setembro a Abril, sendo a evolução média de 32,5 dias a 21,4°C e de 33 a 43 dias nos meses de Maio a Agosto com evolução média de 36 dias a 16.9°C. No campo foram libertados 262 adultos de Lixophaga. Do total, 139 distribuídos em cultura de milho (Lote A) e os restantes, em cultura de cana (Lotes B e C). Recuperamos 76 pupários vivos e 38 vazios. A porcentagem total de parasitismo verificado foi de 28,7%. Temos recuperado diversos pupários após um ano das primeiras libertações (1951), o que vem demonstrar que a Lixophaga já se estabeleceu nesta região. Nos meses de Maio a Agosto, a capacidade larval torna-se mais reduzida devido a baixa temperatura. Nesse período, deve- se conservar os adultos em ambiente cuja temperatura seja de 22 a 25°C, a fim de que os mesmos não paralisem sua reprodução.No período da gestação, a Lixophaga demonstrou ser mais resistente do que as outras duas espécies nativas. O potencial de reprodução da Metagonistylum e da Parathersia é maior do que a da Lixophaga. Na técnica de criação e conservação da broca parasitada, utilizamos pontas de cana introduzidas em recipientes contendoágua, uma vez que os roletes são de efêmera duração e precisam ser substituídos constantemente O ciclo médio de Metagonistylum sendo de 38 dias, conforme determinamos e o de Paratheresia de 47 dias de acordo com o trabalho de SOUZA (7), concluímos que o ciclo médio de Lixophaga é menor comparando àquelas espécies. Embora, os parasitos da broca, sejam na natureza, hiper parasitados, em nada vem alterar esse método, um vez que quando o parasito destruir completamente a broca e passar ao estado de prê-pupa, observamos pelas experimentações, que somente nessa fase poderá vir a ser hiperparasitado e assim mesmo em porcentagem insignificante, não indo além de 5%. Pela criação sistemática desses parasitos em larga escala e sua distribuição periódica na cultura de cana, não dependendo, portanto, de sua multiplicação total na natureza, anula-se o efeito do hiperparasitismo e consegue-se reduzir grandemente a infestação ocasionada pela broca.
Estudos sôbre Ascia monuste orseis (GODART, 1818) (Lep., Pierididae)
Authors: Lordello Luiz Gonzaga E. , Rodrigues Rubens Alves
Published: November 2012

A biologia de Ascia monuste orseis (Godart, 1818) (Lep., Pierididae) foi estudada. O material utilizado foi coligido em Campinas e Piracicaba (Estado de São Paulo), durante os meses de dezembro de 1951 e janeiro de 1952 e constituiu-se principalmente de posturas do inseto. O número máximo de ovos, obtido de uma fêmea, em condições de laboratório, foi de 202, sendo registradas algumas observações sobre o comportamento da borboleta durante a oviposição na natureza. Os ovos e as posturas são descritos. A incubação exigiu cerca de 4 dias. Durante a vida larvária, a espécie passa por 5 estádios, sofrendo, portanto, 4 ecdises. São descritas as lagartas em tôdas essas idades. O ciclo completo, de ôvo a imago, andou ao redor de 22 dias. O 5º. estádio larval mostrou-se, de todos, o mais longo, consumindo 3 até 6 dias. O período de crisálida abrangeu 6 a 7 dias. Os adultos viveram, em insetário, 5 a 9 dias, quer em presença ou em ausência de uma mecha de algodão hidrófilo em-bebida de uma mistura de água e mel. Unicamente um caso de parasitismo foi verificado, os Autores concluindo que, nestas regiões de São Paulo, na época em que as observações foram feitas, a espécie é muito pouco perseguida por agentes naturais de controle. O parasito foi identificado pelo Professor Luis De Santis, da Universidade de La Plata (Rep. Argentina), como Pteromalus caridei Brèthes, 1913, interessante Hymenoptera da família Pteromalidae. Os Autores procuraram esclarecer a ação do pardal - Passer domesticus domesticus (L.) - com relação às lagartas de A. m. orseis, uma vez que há, entre olericultures, a crença de que o referido Ploceidae constitui inimigo do Lepidoptera em estudo. As observações colhidas não permitiram uma conclusão, sendo, contudo, de molde a negar a ação do pássaro como devorador das lagartas.
Contribuição para o conhecimento de algumas leguminosas como forrageiras - Aceitação, palatabilidade e toxides - Testes em coelhos e cobaios
Authors: Vandoni Romulo
Published: November 2012

Foram utilizadas na alimentação de coelhos e cobaios as seguintes Leguminosas: Mucuna pruriens Wall, Styzolobium Deeringianum Steph e Bort, Indiqojera hirsuta Lam, Tephrosia cândida, Cajanus cajam Millsp, Canavália ensiformes DC, Clitoria ternatea L., Crotalaria juncea L., C. paulina, C. spectabilis Hoth, C. striata DC, C. brevijlora, C. campista, C. lanceolata e C. anagyroides. Delas, apenas a Crotalaria spectabilis Roth se mostrou altamente tóxica, ao ponto de matar os animais em experiência. Os quadros I e II demonstram a aceitação e aproveitamento controlado em dez dessas espécies, com coelhos. Foram feitos também algumas observações da toxidês das sementes com cobaios cujos resultados são apresentados nas conclusões parciais.
Em torno das "Diretrizes curriculares nacionais para a educação das relações étnico-raciais e para o ensino de história e cultura afro-brasileira e africana": uma conversa com historiadores
Authors: Abreu Martha , Mattos Hebe
Published: November 2012

A partir do crescimento do interesse de professores e secretarias de educação na organização de políticas de combate ao racismo, este artigo procura discutir e apresentar alguns subsídios para a implementação das "Diretrizes curriculares nacionais para o ensino das relações étnico-raciais e de história e cultura afro-brasileira e africana", aprovadas em 2004. Entendemos as "Diretrizes" como uma importante estratégia pedagógica para levar à escola, pela primeira vez, a discussão das relações raciais no Brasil, tantas vezes silenciada ou desqualificada pelas avaliações de que o Brasil era uma democracia racial. Demos especial atenção aos limites e possibilidades de trabalho com os conceitos de cultura afro-brasileira e identidade negra.
Procedimento para seleção de interfaces para produtos modulares baseado no ciclo de projeto de produtos
Authors: Scalice Régis Kovacs , Andrade Luiz Fernando Segalin de , Forcellini Fernando Antonio
Published: November 2012

Este artigo aborda a definição de alternativas de interfaces durante desenvolvimento de produtos modulares. Entende-se por interfaces a fronteira entre os módulos que compõem o produto, bem como as interações existentes entre o meio-ambiente em que o produto está inserido e com seus possíveis usuários. Para realizar o projeto de interfaces é proposto um procedimento que auxilia na concepção de alternativas e em sua priorização, de forma a facilitar a tomada de decisão por parte da equipe de projeto. O procedimento proposto foi validado por sua aplicação no desenvolvimento de produtos modulares para o cultivo e beneficiamento de mexilhões em Santa Catarina. Os resultados obtidos demonstram o potencial da ferramenta.
Eficiência e impacto do contexto na gestão através do DEA: o caso da UEG
Authors: Rosano-Peña Carlos
Published: November 2012

Este trabalho mostra a contribuição do método Análise envoltória de dados (DEA) na avaliação da eficiência técnica de organizações que operam em contextos diferenciados. A aplicação do DEA na Universidade Estadual de Goiás (UEG) demonstra que 20 das 39 unidades analisadas são ineficientes. As 20 sofrem o efeito negativo do entorno medido pelo Índice de Desenvolvimento Humano dos Municípios de 2000 - IDH-M. Isolando-se esse efeito, cai o número de ineficientes para 11 e a média dos índices de eficiência técnica passa para 0,95, o que indica que essas unidades poderiam produzir o mesmo reduzindo os insumos em 5%, no mínimo. Alternativamente, a UEG, mantendo o nível atual de insumos, poderia incrementar sua produção em 7%. A pesquisa também mostrou que das 20 unidades pesquisadas 11 estão subdimensionadas e 9 superdimensionadas. Essa informação poderia ser utilizada para reduzir custos e otimizar o porte dessas unidades.
First report of phytophagous stink bug in chicory crop
Authors: Krinski Diones
Published: November 2012

This study reports the first occurrence of the stink bug Edessa meditabunda (F.) (Heteroptera: Pentatomidae) on chicory in Pará State, Brazil (7°7'45.59"S 55°23'20.99"W). Samples were taken at Florentino Farm, municipality of Novo Progresso from a plot of plants (5mx1,25m). Sixty-eight chicory plants were sampled and 1.649 adults, 636 nymphs and 1.012 egg masses were obtained.
Variabilidade genética de acessos da cultivar ‘BRS Bela’ de Stylosanthes guianensis usando marcadores moleculares RAPD
Authors: Matida Elizangela Tieko , Chiari Lucimara , Simeão Rosangela Maria , Fernandes Celso Dornelas , Arguelho Edihanne Gamarra , Both Diego Pazinato
Published: November 2012

Taxonomicamente, Stylosanthes guianensis está dividida em quatro variedades botânicas: var. guianensis, var. pauciflora, var. canescens e var. microcephala. A cultivar 'BRS Bela' é uma das duas cultivares dessa leguminosa forrageira registradas no Brasil e é composta por uma mistura física de sementes de quatro acessos pertencentes a variedades botânicas ainda desconhecidas. O objetivo deste trabalho foi caracterizar a variabilidade genética entre os quatro acessos que compõem esta cultivar e determinar suas inter-relações com acessos de variedades botânicas conhecidas, usando a técnica de polimorfismos de DNA amplificados ao acaso (RAPD). Foram analisados 10 primers decâmeros em 36 acessos, do banco de germoplasma da Embrapa gado de Corte, de S. guianensis: 14 da variedade botânica pauciflora, 11 da var. guianensis, quatro da var. canescens, três da var. microcephala e os quatro acessos da cultivar 'BRS Bela'. As bandas amplificadas foram analisadas como dados binários e uma matriz de similaridade genética foi gerada, usando coeficiente de Jaccard. Com base na dissimilaridade genética, os acessos foram agrupados pelos métodos de ligação média entre grupos (UPGMA) e Tocher. A média de similaridade genética dentro das variedades botânicas foi de 0,72 para var. pauciflora, 0,63 para var. microcephala, 0,62 para var. canescens e 0,46 para var. guianensis. Entre os quatro acessos da cultivar 'BRS Bela', esta média foi de 0,62. Ambos os métodos de agrupamento geraram resultados similares e tenderam a agrupar os acessos da mesma variedade botânica. Os acessos da cultivar 'BRS Bela' foram agrupados com acessos var. guianensis. Os resultados mostram que há variabilidade genética dentro das variedades botânicas de S. guianensis e entre os acessos da cultivar 'BRS Bela' e que existe uma tendência ao agrupamento por variedade botânica.
Estudo da mistura do éter diglicidílico do bisfenol-A com poli(etileno-co-acetato de vinila)-g-poli(metacrilato de metila) por espectroscopia dielétrica e calorimetria exploratória diferencial
Authors: Leyva M.E. , Garcia F.G. , Soares B.G.
Published: November 2012

As curvas calorimétricas e os espectros de relaxação dielétrica correspondentes às misturas do éter diglicidílico do bisfenol-A com diferentes concentrações do copolímero poli(etileno-co-acetato de vinila)-g-poli(metacrilato de metila) (EVA-g-PMMA) foram obtidos utilizando a calorimetria exploratória diferencial (DSC), e a espectroscopia de relaxação dielétrica (DSR), respectivamente. A temperatura de transição vítrea (Tg) do segmento de PMMA aumenta com o conteúdo de copolímero na mistura. O comportamento da Tg foi descrito pela equação de Gordon-Taylor, utilizando a fração mássica de PMMA. Nos espectros dielétricos, aparecem as relaxações do tipo α características dos dois segmentos moleculares. Neste caso, o aumento da concentração de copolímero provocou o aumento da temperatura de relaxação α correspondente ao segmento de PMMA, e não foi observada mudança na relaxação α para a fração de EVA. Estes comportamentos revelam que os segmentos estruturais do copolímero apresentam interações bem diferenciadas com o monômetro epoxídico. O segmento de PMMA é miscível, portanto, provocou fortes interações com a resina quando comparado à fração de EVA, que não manifestou interação aparente e originou a heterogeneidade do sistema.
Fabricación y caracterización de espumas de alúmina para aplicación en quemadores porosos radiantes
Authors: Herrera A.M. , Álvarez O. , Escobar J. , Moreno V. , Oliveira Jr. A.A.M. , Hotza D.
Published: November 2012

En los quemadores radiantes, la fuente de calor requiere un medio poroso en donde se lleva a cabo la reacción de combustión, que hace más eficiente la transferencia de calor. En este trabajo se realizó un estudio de la reología de la suspensión de alúmina fina, cuyos parámetros de viscosidad y tixotropía fueron la base para la selección de la formulación más adecuada para la fabricación de espumas cerámicas por el método de réplica. Las espumas poliméricas precursoras presentaron mayor porosidad y permeabilidad, en respuesta a la presencia de paredes finas y 99% de celdas abiertas. La mayor resistencia mecánica a la compresión la obtuvo la formulación con mayor carga de sólidos, bajo las mismas condiciones de prueba.
Fotocatálise do corante vermelho de metila com TiO2 obtido pelo método Pechini
Authors: Ribeiro P.C. , Lira H.L. , Sasaki J.M. , Costa A.C F. M.
Published: November 2012

O dióxido de titânio tem sido bastante investigado para a remoção de poluentes orgânicos. É um material polimórfico, o qual dependendo das condições e tipo de método de síntese empregado na sua preparação pode ser monofásico ou bifásico, com predominância de uma das fases. Sendo assim, este trabalho propõe a avaliação da estrutura, morfologia e atividade fotocatalítica na degradação do corante vermelho de metila por amostras de TiO2 sintetizado pelo método Pechini com relação de ácido cítrico/cátion metálico de 4:1 e 6:1. As amostras sintetizadas foram calcinadasa 500ºC por 1hora e foram caracterizadas pela técnica de difração de raios X em amostras policristalinas com o uso do método de refinamento Rietveld, análise textural, microscopia eletrônica de varredura e fotocataliticamente em testes de bancada, usando o corante vermelho de metila. Os resultados obtidos mostraram que a amostra 4:1 levou à formação das duas fases, com 89% dafase anatásio e 11% da fase rutilo, enquanto a amostra 6:1 levou apenas à formação da fase anatásio. A amostra 4:1, que apresentou a mistura da fase anatásio e rutilo demonstrou ser mais eficiente fotocataliticamente do que a amostra 6:1.
Geographically Based Diversity in Mitochondrial DNA of North American Lygus lineolaris (Hemiptera: Miridae)
Authors: Burange Prasad S , Roehrdanz Richard L , Boetel Mark A
Published: November 2012

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is a highly polyphagous insect pest. It is the most widely distributed Lygus species in North America, and it is the most prevalent member of the genus Lygus in the eastern half of the continent. We sampled multiple populations of L. lineolaris from three disparate regions of North America, and used parts of the mitochondrial genes cytochrome oxidase 1 and cytochrome oxidase 2 as markers to assess intraspecific diversity of this species. Results indicated that there is an association between genetic population structure and geography. Neighbor-joining, maximum parsimony, Bayesian inference analysis, and maximum likelihood trees suggested that most L. lineolaris individuals belong to two closely related clades showing sympatric distribution. Mitochondrial DNA haplotypes common to widely dispersed populations were observed. Morphological identities of five L. lineolaris samples that formed an outlier clade indicated incongruence between morphological identity and genetic data. Individuals from the two major clades and one disparate clade did not exhibit recognizable morphological differences. No strong host plant associations were observed among clades, thus, genetic structuring in this species appears to mostly be geographically based. This study represents the first attempt to survey cytochrome oxidase 1 and cytochrome oxidase 2 variation within L. lineolaris and to use those genes to construct a molecular phylogeny for this species.
Biochemical Evidence that Dendroctonus frontalis Consists of Two Sibling Species in Belize and Chiapas, Mexico
Authors: Sullivan Brian T , Niño Alicia , Moreno Benjamín , Brownie Cavell , Macías-Sámano Jorge , Clarke Stephen R , Kirkendall Lawrence R , Zúñiga Gerardo
Published: November 2012

Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) is a major economic pest of pines in the United States, Mexico, and Central America. We report biochemical investigations relevant to the taxonomic status and semiochemistry of two distinct morphotypes of D.frontalis recently detected in the Central American region. Morphotype A beetles (pre-episternal area of prothorax of both sexes smooth, bulging callus on anterolateral margin of prothorax of females) and morphotype B beetles (pre-episternal area of prothorax of both sexes with fine ridges, reduced female callus) collected in infestations in Chiapas, Mexico differed significantly in their production of 10 behaviorally-active compounds occurring in the genus Dendroctonus, including the major pheromone components for D. frontalis. Notably, host-attacking morphotype B females produced hundreds of nanograms of both endo-brevicomin and frontalin, whereas morphotype A females produced similar amounts of frontalin but subnanogram quantities of endo-brevicomin. Reanalysis of a published D. frontalis trapping study in Chiapas indicated that both morphotypes responded in greatest numbers when frontalin and endo-brevicomin baits were both present. In addition, we quantified 18 different cuticular hydrocarbons (the methyl-branched alkane components) from both morphotypes collected in Belize and Chiapas as well as morphotype A beetles from the southeastern United States, and principal component analysis revealed nonoverlapping clusters associated with either morphotype. This evidence of two distinct, complex phenotypes coexisting in the same sites and host trees supports the hypothesis that the D. frontalis morphotypes represent separate species and consequently indicates that the taxonomy of D. frontalis should be re-evaluated in the Central American region.
Everyone's a Loser: Parasitism of Late Instar Whiteflies byEncarsia inaronhas Negative Consequences for Both Parasitoid and Host
Authors: Brady Cristina M , White Jennifer A
Published: November 2012

Despite strong evolutionary pressure for an ovipositing parasitoid to use only hosts with high suitability, there are examples of parasitoid attacks that fail. Here we document one such instance, in which a parasitoid does not discriminate against an inappropriate host life stage, resulting in negative consequences for both the parasitoid and host. The solitary koinobiont parasitoid Encarsia inaron (Walker) was originally imported to North America to control the ash whitefly, Siphoninus phillyreae (Haliday), but readily parasitizes and completes development in other whitefly hosts, including Bemisia tabaci (Gennadius) and Trialeurodes abutiloneus (Haldeman). For both B. tabaci and T. abutiloneus, when younger host instars were parasitized, parasitism was successful and adult wasps emerged. In fourth instar hosts, however, adult parasitoids rarely emerged; rather, adult whiteflies were produced. Dissections over time showed that the wasp larvae continued to develop within these adult whiteflies, but did not successfully complete development. Furthermore, the adult whiteflies suffered reduced fecundity compared with nonparasitized adults and ultimately died as a result of parasitism. Our results suggest that E. inaron may be incapable of arresting the development of hosts parasitized as fourth instars, instead engaging in a developmental race that results either in a win for the parasitoid, or a loss for both the parasitoid and the host.
The Use of Trap-Nests to Manage Carpenter Bees (Hymenoptera: Apidae: Xylocopini), Pollinators of Passion Fruit (Passifloraceae:Passiflora edulisf.flavicarpa)
Authors: Junqueira C N , Hogendoorn K , Augusto S C
Published: November 2012

Carpenter bees are the main pollinators of passion fruit, a crop classified as vulnerable to pollinator decline because it is strictly self-incompatible. We investigated cost-effective management strategies to increase the presence of female carpenter bees in passion fruit orchards by using trap-nests in bee shelters. Transfers of nests containing females of X. frontalis and X. grisescens between different sites were significantly more successful when the nests contained brood cells. Supplying a bee shelter with a combination of suitably sized empty bamboo stalks and active nests of carpenter bees can increase the population of actively nesting bees by >200% during the course of 23 mo, as a consequence of the emergence of brood from the introduced nests and the attraction of bees from the surroundings. In conclusion, our methods lead to improved success of introducing, increasing and maintaining carpenter bees populations for the pollination of passion fruit crops.
The effect of environmental and phylogenetic drivers on community assembly in an alpine meadow community
Authors: Yang Zhongling , Powell Jeff R. , Zhang Chunhui , Du Guozhen
Published: November 2012

To predict the consequences of environmental change on plant communities at local scales, one needs to understand the regional drivers structuring these communities. Here, we used a formal analytical framework incorporating functional traits and evolutionary histories to understand the importance of environmental filtering and species interactions in the assembly of alpine plant communities. The study was conducted in the Tibetan Plateau using field plots experiencing changes in land use (fertilization and grazing). We observed evidence for both trait‐based convergence (associated with plant height and tissue nitrogen) and divergence (associated with specific leaf area) within alpine plant communities, suggesting that environmental filtering and limiting similarity are acting simultaneously during assembly processes. Although we did not observe evidence of phylogenetic niche conservatism in relation to intensified land use, we did observe support for the phylogenetic structure of plant communities influencing community‐weighted mean trait values, suggesting that evolutionary constraints represent a significant driver of community assembly in this system. Therefore, evolutionary and ecological processes may have independent effects on alpine plant communities facing land use intensification.
Competition favors elk over beaver in a riparian willow ecosystem
Authors: Baker Bruce W. , Peinetti H. Raul , Coughenour Michael B. , Johnson Therese L.
Published: November 2012

Beaver (Castor spp.) conservation requires an understanding of their complex interactions with competing herbivores. Simulation modeling offers a controlled environment to examine long‐term dynamics in ecosystems driven by uncontrollable variables. We used a new version of the SAVANNA ecosystem model to investigate beaver (C. canadensis) and elk (Cervus elaphus) competition for willow (Salix spp.). We initialized the model with field data from Rocky Mountain National Park, Colorado, USA, to simulate a 4‐ha riparian ecosystem containing beaver, elk, and willow. We found beaver persisted indefinitely when elk density was ≤20 elk km−2. Beaver persistence decreased exponentially as elk density increased from 30 to 60 elk km−2, which suggests the presence of an ecological threshold. The interaction of beaver and elk herbivory shifted the size distribution of willow plants from tall to short when elk densities were ≥30 elk km−2. The loss of tall willow preceded rapid beaver declines, thus willow condition may predict beaver population trajectory in natural environments. Beaver were able to persist with slightly higher elk densities if beaver alternated their use of foraging sites in a rest‐rotation pattern rather than maintained continuous use. Thus, we found asymmetrical competition for willow strongly favored elk over beaver in a simulated montane ecosystem. Finally, we discuss application of the SAVANNA model and mechanisms of competition relative to beaver persistence as metapopulations, ecological resistance and alternative state models, and ecosystem regulation.
Projected range shifting by montane mammals under climate change: implications for Cascadia's National Parks
Authors: Johnston Kevin M. , Freund Kathryn A. , Schmitz Oswald J.
Published: November 2012

We examined potential impacts of climate change over the next century on eight mammal species of conservation concern in western Washington State, under four warming scenarios. Using two species distribution models, including a logistic regression‐based model and the “maximum entropy” (MaxEnt) model, we predicted the location and extent of the potential current and future range of each species based on a suite of environmental and geographical variables. Both models projected significant losses in range size within the focal area over the next century across all warming scenarios. Projections suggest that future ranges of high elevation species are likely to shrink inward and upward rather than shifting into new areas, and the average range elevation of most species is projected to increase significantly over time. Future projections for higher elevation species largely agreed across species distribution models, global climate model data, and carbon emission scenarios, although projections for lower elevation species were less consistent. The high elevation of the major national parks in this region is likely to aid in their ability to continue to support these species, and they are predicted to continue to act as important protected refuges, even while species' ranges may shrink dramatically elsewhere.
Locally Delivered 1% Metformin Gel in the Treatment of Smokers with Chronic Periodontitis: A Randomized Controlled Clinical Trial
Authors: Rao Nishanth S. , Pradeep A.R. , Kumari Minal , Naik Savitha B.
Published: November 2012

Background: Metformin (MF) (1,1‐dimethylbiguanide HCl) is one of the most commonly used oral antihyperglycemic agents for the treatment of type 2 diabetes mellitus. Recently, MF has been shown to have bone‐sparing properties. The present study is designed to investigate the effectiveness of MF 1% in an indigenously prepared, biodegradable, controlled‐release gel, as an adjunct to scaling and root planing (SRP) in treatment of vertical defects in smokers with generalized chronic periodontitis (CP).

Methods: Fifty patients were categorized into two treatment groups: SRP plus 1% MF and SRP plus placebo. Clinical parameters were recorded at baseline and at 3 and 6 months; they included plaque index (PI), modified sulcus bleeding index (mSBI), probing depth (PD), and clinical attachment level (CAL). At baseline and after 6 months, intrabony defect (IBD) fill was radiologically assessed using computer software.

Results: Mean PD reduction and mean CAL gain were found to be greater in the MF group than the placebo group at all visits. Furthermore, a significantly greater mean percentage of bone fill was found in the MF group (26.17% ± 6.66%) than the placebo sites (3.75% ± 8.06%) (P <0.001).

Conclusion: There was greater decrease in mSBI and PD and more CAL gain with significant IBD fill at vertical defect sites treated with SRP plus locally delivered MF, versus SRP plus placebo, in smokers with generalized CP.
Polyphenolic Coumpounds in Chemoprevention of Colon Cancer - Targets and Signaling Pathways
Authors: Rudolf Emil , Andelova Hana , Cervinka Miroslav
Published: November 2012

Colorectal cancer is one of the leading causes of premature death in people worldwide. Due to the fact that malignant conversion of normal colonic cells requires several steps and often proceeds over considerable time periods, primary prevention of this process should include several approaches, with optimization of nutrition and diet being among most important. During past decades, several groups of chemicals (both naturally occurring as well as synthetic) have been studied in terms of their potential chemopreventive role in colorectal cancer development. Naturally occurring plant polyphenols have recently come into scientific focus because of their presence in various popular natural products (wine grapes, teas, berries, peanuts) and, more importantly, due to their reported antiproliferative and cytostatic abilities in various in vitro and in vivo models. This review seeks to summarize the currently known targets and mechanisms whereby polyphenolic compounds interfere with colonic cancer cells while evaluating their chemopreventive potential in vivo.
Oncologists Current Opinion on the Treatment of Colon Carcinoma
Authors: Majer Martin , Akerley Wallace , Kuwada Scott K.
Published: November 2012

Colorectal cancer is a major global health problem with more than a million new cases diagnosed worldwide in 2005. In the United States, this malignancy is the third most common with 145,000 new cases and the second most lethal with 56,000 deaths in 2005. Unfortunately, preclinical diagnostic screening in the U.S. population is less than 30-40 percent. The last decade has ushered in exciting new advances for medical oncologists caring for patients with colorectal cancer. The older cytotoxic chemotherapy drug 5-fluorouracil underwent new formulation, and two new drugs, oxaliplatine and irinotecan, were investigated as adjunctive therapies. Finally, targeted therapies, including monoclonal antibodies against vascular endothelial growth factor (bevacizumab) and the epidermal growth factor receptor (cetuximab), are now standard treatment for metastatic colorectal carcinoma. Systemic adjuvant chemotherapy can be lifesaving in patients with locally advanced colorectal carcinomas, which represent 60-70 percent of cases. For patients with metastatic colorectal cancer, the survival rate has doubled. With more effective drugs in the therapeutic armamentarium, new controversies have arisen. Questions regarding the best schedules for classical cytotoxic chemotherapy were largely answered by contemporary clinical trials. The potential of molecular genetic markers for prognosis or prediction of drug-specific toxicity and efficacy have been explored, but their utility for clinical practice is still being investigated. We will review the rapidly changing, state-of-the-art combination chemotherapy for adjuvant and metastatic disease. We will discuss in detail the c-ERBB family of tyrosine kinases as therapeutic targets in colorectal cancer.
Fused Xanthone Derivatives as Antiproliferative Agents
Authors: Pouli Nicole , Marakos Panagiotis
Published: November 2012

Xanthones have been isolated from several natural sources, mainly belonging in Guttiferae and Gentianaceae families as secondary plant metabolites and many of them are endowed with diverse pharmacological properties. We have focused in the study of cytotoxic fused xanthone derivatives, having in mind that some furano- and pyranoxanthone natural products are particularly interesting, in terms of cytotoxic potency and novelty in their mechanism of action and could serve as lead compounds for the development of clinically effective anticancer agents. In this review, a general classification has been attempted based on the type of ring fusion, in such a way that natural compounds as well as synthetic derivatives are discussed. The furanoxanthone psorospermin is a highly promising isolated xanthone derivative exhibiting significant cytotoxicity through a novel mechanism of action, being an irreversible topoisomerase II poison and it was selected for further development as an antineoplastic agent. An important number of pyranoxanthones have been synthesized using as lead compound the acridone alkaloid acronycine. Adducts on the double bond of these compounds provided cytotoxic derivatives possessing cell-cycle selectivity. The synthesis of pyranoxanthones bearing aminosubstituted side-chains resulted in compounds that exhibit markedly improved cytotoxicity towards leukemic and solid tumor cell lines. Azabioisosters of the aminoderivatives exhibit solid tumor selectivity whereas additional pyrazole or/and benzene ring fusion has been incorporated into the xanthone skeleton and resulted in compounds with promising activity, which retain full antiproliferative activity against P-glycoprotein-overexpressing cells. Gambogic acid, a highly effective anticancer drug candidate with low toxicity to normal tissue, together with structurally related representative analogues are also mentioned.
Tyrosine Kinase Blockers: New Hope for Successful Cancer Therapy
Authors: Pytel Dariusz , Sliwinski Tomasz , Poplawski Tomasz , Ferriola Deborah , Majsterek Ireneusz
Published: November 2012

Tyrosine kinases (TKs) are attractive targets for cancer therapy, as quite often their abnormal signaling has been linked with tumor development and growth. Constitutive activated TKs stimulate multiple signaling pathways responsible for DNA repair, apoptosis, and cell proliferation. During the last few years, thorough analysis of the mechanism underlying tyrosine kinases activity led to novel cancer therapy using TKs blockers. These drugs are remarkably effective in the treatment of various human tumors including head and neck, gastric, prostate and breast cancer and leukemias. The most successful example of kinase blockers is Imatinib (Imatinib mesylate, Gleevec, STI571), the inhibitor of Bcr/Abl oncoprotein, which has become a first-line therapy for chronic myelogenous leukemia. The introduction of STI571 for the treatment of leukemia in clinical oncology has had a dramatic impact on how this disease is currently managed. Others kinase inhibitors used recently in cancer therapy include Dasatinib (BMS-354825) specific for ABL non-receptor cytoplasmic kinase, Gefitinib (Iressa), Erlotinib (OSI-774, Tarceva) and Sunitinib (SU 11248, Sutent) specific for VEGF receptor kinase, AMN107 (Nilotinib) and INNO-406 (NS-187) specific for c-KIT kinase. The following TK blockers for treatment of various human tumors are in clinical development: Lapatinib (Lapatinib ditosylate, Tykerb, GW-572016), Canertinib (CI-1033), Zactima (ZD6474), Vatalanib (PTK787/ZK 222584), Sorafenib (Bay 43-9006, Nexavar), and Leflunomide (SU101, Arava). Herein, we discuss the chemistry, biological activity and clinical potential of new drugs with tyrosine kinase blockers for cancer treatment.
Biotechnological Production of Taxol and Related Taxoids: Current State and Prospects
Authors: Exposito O. , Bonfill M. , Moyano E. , Onrubia M. , Mirjalili M. H. , Cusido R. M. , Palazon J.
Published: November 2012

Taxol is one of the most effective anti-cancer drugs ever developed. The natural source of taxol is the inner bark of several Taxus species, but it accumulates at a very low concentration and with a prohibitively high cost of extraction. Another problem is that the use of inner bark for taxol production implies the destruction of yew trees. For all these reasons, the growing demand for taxol greatly exceeds the supply that can be sustained by isolation from its natural source and alternative sources of the drug are being sought. Although taxol has been prepared by total synthesis, the process is not commercially viable. Taxol can also be semisynthetically produced via the conversion of baccatin III or 10-deacethylbaccatinIII found in Taxus needles but the cost and difficulty of the extraction process of the semisynthetic precursors are also very high. The most promising approach for the sustainable production of taxol and related taxoids is provided by plant cell cultures at an industrial level. Taxol is currently being clinically used against different tumour processes but due to the difficulty of its extraction and formulation, as well as the growing demand for the compound, new taxol analogues with improved properties are being studied. In this revision we discuss current research in the design of new taxol-related compounds, the chemical structure/anti-cancer activity relationship and new formulations of the drug. We also consider the optimizing strategies to improve taxol and related taxoid production in cell cultures, as well as the current knowledge of taxol metabolism, all of which are illustrated with examples, some of them from our own research.
Importance and Limitations of Chemotherapy Among the Available Treatments for Gastrointestinal Tumours
Authors: Marin Jose J.G. , Romero Marta R. , Blazquez Alba G. , Herraez Elisa , Keck Emma , Briz Oscar
Published: November 2012

Gastrointestinal tumours constitute one of the worldwide leading causes of death. One important limitation in the battle against these types of cancer is their lack of sensitivity to currently available chemotherapy and the development of drug resistance during treatment. The mechanisms responsible for this refractivity include a reduction in drug uptake, enhanced drug export, intracellular inactivation of the effective agent, alteration of the molecular target, an increase in the activity of the target route to be inhibited or the appearance or stimulation of alternative routes, enhanced repair of drug-induced modification in the target molecules, and activation/inhibition of intracellular signalling pathways, which leads to a negative balance between apoptosis/survival of tumour cells. A better understanding of these mechanisms is needed in order to develop both accurate tests to predict the lack of response to chemotherapy and novel approaches aimed to overcome the drug resistance of gastrointestinal tumours. The complexity of this issue is further increased owing to the existence of marked differences among the types of primary malignant gastrointestinal tumours and the diversity of tissues from which metastatic cells can access the gut. Moreover, inter-individual variability plus the fact that sensitivity/refractivity may change during the evolution of the tumour further complicate the overall situation. The present article reviews anti-cancer agents used either alone or, more frequently, combined in regimens, as neoadjuvant or postsurgical adjuvant chemotherapy within the context of the available curative and palliative therapeutic options used to treat the most common types of cancer of the gastrointestinal tract and pancreas.
2-Deoxy-D-Ribose, a Downstream Mediator of Thymidine Phosphorylase, Regulates Tumor Angiogenesis and Progression
Authors: Nakajima Yuichi , Madhyastha Radha , Maruyama Masugi
Published: November 2012

Angiogenesis plays an important role in tumor metastasis and progression, and thus inhibiting angiogenesis is a promising strategy for treatment of cancer. However, tumor-associated angiogenesis is influenced by various angiogenic factors in the tumor microenvironment. Thymidine phosphorylase (TP, EC 2. 4. 2. 4), an enzyme involved in the reversible conversion of thymidine to thymine, is an important mediator of angiogenesis, tumorigenicity, metastasis and invasion. The angiogenic effect of TP requires the enzymatic activity of TP. TP activity is expressed at higher levels in a wide variety of solid tumors than in adjacent non-neoplastic tissue. The tumor microenvironment (hypoxia, acidosis) regulates the expression of TP, and TP expression in tumor tissue shows significant correlation with microvessel density and poor prognosis. 2-Deoxy-D-ribose (D-dRib), one of the degradation products of thymidine generated by TP activity, promotes angiogenesis and the chemotactic activity of endothelial cells and also confers resistance to hypoxia-induced apoptosis in some cancer cell lines. These findings suggest that D-dRib is a downstream mediator of TP function. 2-Deoxy-L-ribose, a stereoisomer of D-dRib, can inhibit D-dRibs anti-apoptotic effects and suppress metastasis and invasion of TP-expressing tumors in mice. Although the mechanism of action of D-dRib is still unknown, the physiological activities of D-dRib have recently been reported by several groups. We review the role of D-dRib in tumor progression and discuss inhibition of D-dRib as a promising approach for chemotherapy of various tumors.
Role of Tyrosine Phosphatase Inhibitors in Cancer Treatment with Emphasis on SH2 Domain-Containing Tyrosine Phosphatases (SHPs)
Authors: Irandoust Mahban , van den Berg Timo K. , Kaspers Gertjan J.L. , Cloos Jacqueline
Published: November 2012

Protein tyrosine phosphorylation is one of the key mechanisms involved in signal transduction pathways. This modification is regulated by concerted action of protein tyrosine phosphatases and protein tyrosine kinases. Deregulation of either of these key regulators lead to abnormal cellular signaling, which is largely associated with human pathologies including cancer. Although the role of protein tyrosine kinases in cancer is well established, less is known about the involvement of protein tyrosine phosphatases in carcinogenesis and tumor progression. Moreover, several inhibitors targeting protein tyrosine kinases have demonstrated their value in cancer treatment, while interest in protein tyrosine phosphatases as a target for treatment has risen more recently. In this review we describe the progressive efforts and challenges concerning the development of drugs targeting phosphatases as promising novel cancer therapies. We focus on two key regulatory SH2 domain-containing phosphatases, SHP-1 and SHP-2 and one of their substrates, signal regulatory protein alpha. Since SHPs have been linked to many different malignancies, protein tyrosine phosphatases could offer a great spectrum of new, targeted drugs.
Control of Melanoma Invasiveness by Anticollagenolytic Agents: A Reappraisal of an Old Concept
Authors: Bourguet Erika , Sapi Janos , Emonard Herve , Hornebeck William
Published: November 2012

Collagen, the major constituent of human dermis, represents the main barrier against progression of melanoma cells. Several matrix metalloproteinases (MMPs), i.e. collagenase-1 (MMP-1), gelatinase A (MMP-2) and membrane-type 1-MMP (MMP-14), favor melanoma cell invasion through their capacity of degrading collagen and thus, are considered as main targets. Potent inhibitors, as hydroxamate- derived pseudopeptides were first proposed as pharmacological agents to control melanoma invasiveness. These molecules have major drawbacks linked to i) toxicity and ii) absence of specificity, in keeping with the high Zn chelating property of hydroxamates, that might hinder the contribution of the occupancy of other subsites in enzyme inhibition. To date, research focuses on the design of compounds which display a lower affinity for Zn in enzyme active site. For instance, hydroxamate can be replaced by phosphinic acid or hydrazide which further allows synthesis of both right- and left- hand side inhibitors and therefore occupancy of non-primed enzyme subsites. Novel types of selective MMP inhibitors also include non-competitive and mechanism- based inhibitors. Finally, collagenolysis may be controlled by modulating enzyme-substrate interaction through the identification of substances that bind to MMP exosites. Such compounds could be of value by impeding collagenases to associate to plasma-membrane of invading cancer cells.
The PI3K/Akt Pathway as a Target in the Treatment of Hematologic Malignancies
Authors: Kawauchi Kiyotaka , Ogasawara Toshie , Yasuyama Masako , Otsuka Kuniaki , Yamada Osamu
Published: November 2012

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays a central role in growth, proliferation, and anti-apoptotic mechanisms to promote cell cycle and survival not only in normal cells but also in a variety of tumor cells. Thus, the PI3K/Akt pathway, including the downstream effectors, may be a critical target for cancer therapy. Although this pathway has been investigated rigorously and dissected in detail in many physiological systems, its role in molecular target therapy for cancer remains to be established. Hematological malignancies such as leukemia, lymphoma, and myeloma can be ideal models for molecular targeting therapy because of the ease in obtaining samples for examining the effect of inhibitors of target molecules with critical roles in tumor growth and progression. In fact, several inhibitors, such as imatinib in Philadelphia chromosome-positive leukemia and bortezomib in multiple myeloma, have proved quite useful in clinics. Because the PI3K/Akt pathway is active in various hematological malignancies, inhibitors related to this pathway have been confirmed to induce apoptosis in these tumor cells. Efforts to exploit selective inhibitors of the PI3K/Akt pathway that show effectiveness and safety in the clinical setting are underway. We review the recent progress in molecular targeting therapy for the PI3K/Akt pathway in hematologic malignancies.
Public Service Motivation of Public-Versus Private-Sector Employees in a Chinese Context
Authors: Liu Bangcheng , Du Lanying , Wen Hao , Bo Fan
Published: November 2012

To investigate the public service motivation (PSM) of public- and private-sector employees in a Chinese context, comparative studies were conducted with 2 independent samples. In Study 1, confirmatory factor analysis was implemented to assess the level of PSM in 250 public employees.
In Study 2, 247 respondents from private companies were evaluated. Results gained in these studies not only provided evidence supporting the construct validity of this measure of PSM in a Chinese context, but also demonstrated that, comparatively, public-sector employees' levels of PSM were
relatively higher than those of private-sector employees, especially in relation to the attraction to public policymaking and commitment to public interest dimensions of PSM.