206 resultados para Marco Antonio, 82-30 a.C.
Resumo:
The effect of temperature (20 degrees-35 degrees C) on different stages of Romanomermis iyengari was studied. In embryonic development, the single-cell stage eggs developed into mature eggs in 4.5-6.5 days at 25-35 degrees C but, required 9.5 days at 20 degrees C. Complete hatching occurred in 7 and 9 days after egg-laying at 35 and 30 degrees C, respectively. At 25 and 20 degrees C, 85-96 of the eggs did not hatch even by 30th day. Loss of infectivity and death of the preparasites occurred faster at higher temperatures. The 50 survival durations of preparasites at 20 and 35 degrees C were 105.8 and 10.6 hr respectively. They retained 50 infectivity up to 69.7 and 30.3 hr. The duration of the parasitic phase increased as temperature decreased. Low temperature favoured production of a higher proportion of females which were also larger in size. The maximum time taken for the juveniles to become adults was 14 days at 20 degrees C and the minimum was 9 days at 35 degrees C. Oviposition began earlier at higher temperature than at lower temperature. However, its fecundic period was shorter at 20 degrees C than at 35 degrees C indicating enhanced rate of oviposition at 20 degrees C. Fecundity was adversely affected at 20 degrees C and 35 degrees C. It is shown that the temperature range of 25 degrees-30 degrees C favours optimum development of R. iyengari.
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Resistance in Mycobacterium tuberculosis to isoniazid (INH) is caused by mutations in the catalase-peroxidase gene (katG) , and within the inhA promoter and/or in structural gene. A small percentage (~ 10%) of INH-resistant strains do not present mutations in both of these loci. Other genes have been associated with INH resistance including the gene encoding for NADH dehydrogenase (ndh) . Here we report the detection of two ndh locus mutations (CGT to TGT change in codon 13 and GTG to GCG change in codon 18) by analyzing 23 INH-resistant and in none of 13 susceptible isolates from Brazilian tuberculosis patients. We also detected two isolates without a mutation in ndh, or any of the other INH resistance-associated loci examined, suggesting the existence of additional, as yet to be described, INH resistance mechanisms.
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Lipid bodies [lipid droplets (LBs)] are lipid-rich organelles involved in lipid metabolism, signalling and inflammation. Recent findings suggest a role for LBs in host response to infection; however, the potential functions of this organelle in Toxoplasma gondii infection and how it alters macrophage microbicidal capacity during infection are not well understood. Here, we investigated the role of host LBs in T. gondii infection in mouse peritoneal macrophages in vitro. Macrophages cultured with mouse serum (MS) had higher numbers of LBs than those cultured in foetal bovine serum and can function as a model to study the role of LBs during intracellular pathogen infection. LBs were found in association with the parasitophorous vacuole, suggesting that T. gondii may benefit from this lipid source. Moreover, increased numbers of macrophage LBs correlated with high prostaglandin E2 (PGE2) production and decreased nitric oxide (NO) synthesis. Accordingly, LB-enriched macrophages cultured with MS were less efficient at controlling T. gondii growth. Treatment of macrophages cultured with MS with indomethacin, an inhibitor of PGE2 production, increased the microbicidal capacity against T. gondii. Collectively, these results suggest that culture with MS caused a decrease in microbicidal activity of macrophages against T. gondii by increasing PGE2 while lowering NO production.
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No conhecimento em Administração, não é simples encontrar a discussão sobre como sistematizar uma pesquisa acadêmica para a criação de métodos de gestão (frameworks). Como planejar uma pesquisa exploratória, qualitativa e interdisciplinar, para a geração de métodos de planejamento e gestão, é o foco neste trabalho. A pesquisa bibliográfica (desk research), a análise documental, a grounded theory e o estudo de caso são métodos de pesquisa que podem ser utilizados nos trabalhos que produzem sequências de etapas gerenciais, apesar da importância de muitos outros na pesquisa qualitativa. A contribuição empírica deste trabalho começa com a apresentação de diferentes métodos de gestão, aprovados recentemente em journals e conferências acadêmicas, e que foram construídos sob um método (processo) comum de pensamento. Na sequência, além da discussão de como estruturar uma pesquisa científica para a geração de métodos gerenciais, apresentam-se os processos para publicação (e reconhecimento) dessa linha de trabalho.
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O objetivo neste trabalho é contribuir com o repensar da natureza e do significado do marketing de lugar presente na literatura, descrevendo as três principais perspectivas influentes em seu desenvolvimento – promoção, planejamento e branding – e apresentar uma análise crítica de seu processo de evolução. No intuito de orientar o entendimento, evitar interpretações individuais e propor uma linguagem comum, a análise compreende a convergência das perspectivas em um conceito caracterizado como uma importante ferramenta de gerenciamento das trocas que ocorrem em âmbito territorial visando ao desenvolvimento socioeconômico da localidade. Como contribuição, sugere-se uma estruturação para investigações futuras identificando lacunas entre a teoria do marketing de lugar e a forma como é compreendido, assim como as dificuldades significativas para sua implementação.
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ABSTRACT This paper provides evidence on the market reaction to corporate investment decisions whose shareholder value is largely attributed to growth options. The exploratory research raised pre-operational companies and their operational pairs on the same economy segments. It had the purpose of investigating the existence of statistical differentiation from financial indicators that reflect the installed assets and growth assets, and then study the market reaction to changes in fixed assets as a signaling element about investment decisions. The formation process of operational assets and shareholder value almost exclusively dependent on asset growth stands out in the pre-operational companies. As a result, differentiation tests confirmed that the pre-operational companies had their value especially derived on growth options. The market reaction was particularly bigger in pre-operational companies with abnormal negative stock returns, while the operational companies had positive returns, which may indicate that the quality of the investment is judged based on the financial disclosure. Additionally, operational companies' investors await the disclosure to adjust their prices. We conclude that the results are consistent with the empirical evidence and the participants in financial markets to long-term capital formation investments should give that special attention.
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Avaliar as crenças acerca dos graus e riscos atribuídos pelos universitários a diferentes práticas sexuais e comparálas com a atribuição feita por especialistas em AIDS, constituíram o objetivo deste estudo. Um questionário composto por 25 itens (Escala de Probabilidade do tipo Likert), referentes à práticas/hábitos sexuais foi aplicado a alunos dos cursos de graduação em Enfermagem e Obstetrícia, Medicina, Psicologia, Farmácia-Bioquímica, que aquiesceram em respondê-lo. Através deanálise fatorial, usando-se o Sistema Varimax de Rotação, 25 itens foram distribuídos em sete fatores, sendo cinco itens excluídos. Dos 20 itens, 5 foram analisados neste trabalho, compondo dois fatores. O Fator X foi constituído pelos itens 1(sexo vaginal com preservativo) e 2(sexo anal com preservativo). No Fator Y foram alocados os itens: 3(relação com pessoa do sexo oposto), 4(relação vaginal sem preservativo) e 5(sexo anal sem preservativo). Em 80% dos 5 itens, observou-se que os estudantes apresentam conhecimento compatível ao preconizado pelos especialistas. Entretanto faz-se necessária a educação continuada a estes alunos, considerando-os enquanto pessoa e futuro profissional prestador de assistência aos indivíduos infectados pelo HIV ou com AIDS.
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Fecundity and longevity of Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) at different temperatures and commercial chrysanthemum cultivars (Dendranthema grandiflora Tzvelev). The aphid A. gossypii is one of the main pests in a number of crops both under field and protected conditions. The objective of the present study was to evaluate the fecundity and longevity of A. gossypii under different temperatures and commercial chrysanthemum cultivars (Yellow Snowdon, White Reagan and Dark Splendid Reagan) with different trichomes densities (11.3; 16.6 and 21.6 trichome/mm² of the leaf, respectively) The trials were carried out in climatic chambers, at four temperatures (15, 20, 25 and 30 ±1 °C), 70 ± 10% RH and photophase 10h. The reproductive period significantly decreased with increase of temperature in the three cultivars. In Yellow Snowdon cultivar average duration of the reproductive period was 14.3 days at 25 °C. The maximum fecundity was obtained at the temperature of 25 ºC with 3,1; 2,8 and 3,6 nymphs/female/day in the Yellow Snowdon, White Reagan and Dark S. Reagan cultivars, respectively. The total fecundity was reduced by extreme temperatures (15 and 30 °C), and was obtained at 25 °C with 35,9 nymphs/female. Females maintained in Yellow Snowdon cultivar significantly showed superiority (30,7 nymphs/female) in total fecundity in relation to White Reagan (22,1 nymphs/female) and Dark S. Reagan (22,9 nymphs/female). The Yellow Snowdon cultivar (with a lower trichome density) had a significant influence in daily and total capacity of nymphs production, showing a higher fecundity of A. gossypii females. The aphid's longevity was affected by cultivars and temperature, and this longevity decreased whit increase of temperature. The results showed that there was an interaction between the temperature and host plant on reproductive parameters of A. gossypii.
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Several hypotheses have been proposed to explain the patterns of host plant utilization by herbivorous insects in natural communities. We tested four hypotheses aiming to understand the pattern of attack by gall-inducing insects on the dioecious shrub, Baccharis pseudomyriocephala (Asteraceae). The shrub occurs in the Parque Estadual do Itacolomi, Southeastern Brazil, and supports ten species of galling insects. The following hypotheses were tested: i) male plants are more attacked by galling insects than female plants; ii) larger plant modules are preferentially attacked by galling insects; iii) galling insects perform better on larger modules than on smaller modules; iv) galling insects increase in abundance with meristematic availability. To address these questions, 240 plants (120 of each sex) were sampled in both reproductive and vegetative periods. We recorded the growth rate (4 cm), inflorescence and fruit production, attack rates of the galling insects, and their survivorship and mortality per shoot (module). Modules were separated into size classes (cm) and analyzed by regressions and ANCOVAs. Module size and reproductive effort were positively correlated with host plant size. We did not observe any effect of host plant gender on either variables. In the same way, host plant sex did not show any influence on the abundance and richness of galling insects. Although the abundance of galling insects showed a positive correlation with shoot size, the trend disappeared when the analyses were performed taking into consideration the number of galls per unit of growth (number of galls/cm of shoot) or biomass (number of galls/dry weight). Larval survivorship was not influenced by shoot size. Also, we observed that the abundance of one species of hemipteran galling insect showed a positive relation with leaf biomass. Therefore, we conclude that gender and vigor of this plant species do not influence the community structure of its galling herbivores.
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The interaction patterns between the dioecious shrub Baccharis concinna Barroso (Asteraceae) and its speciose galling insect community were studied in southeastern Brazil. Two hypotheses were tested in this study: "the differential reproduction and growth hypothesis" that predicts that male plants present fewer reproductive structures and are larger than female plants; and the 'sex-biased herbivory hypothesis' that predicts that male plants support a larger abundance of insect galls than female plants. Plants did not show sexual dimorphism in growth (= mean leaf number). However, male plants had longer shoots and a lower average number of inflorescences than female plants. These results corroborate the hypothesis that male plants grow more and reproduce less than female plants. No statistically significant difference was found in the number of galls between male and female plants, but a sex by environmental effect on gall number was detected. When each species of galling insect was individually analyzed per population of the host plant, the rates of attack varied between sex and population of the host plant, and they were highly variable among the species of galling insects. These results highlight the importance of the interaction between sex and environment in the community structure of galling insects and indicate that other variables besides host sex may influence the patterns of attack by galling herbivores.
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Problems regarding the order of authorship of scientific papers have become more frequent and more abusive. These problems may have heightened due to the ever increasing pressure to "publish or perish" in the academic world, given that the publication of scientific articles has become the benchmark of success in a field with few job opportunities. This article reviews the abuses in the authorship of scientific papers. Different examples are given of the most common problems and recommendations are provided for authors and journal editors.
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The present study was carried out in three localities of the state of São Paulo, Brazil: Araras (Dec/03-Dec/06), São Carlos (Nov/04-Nov/06) and Rifaina (Jul/04-Dec/06). Trap-nests were distributed among sites in the sampling areas and were collected every 35 days. Data from 295 nests indicate that T. aurifrons is a multivoltine species, with higher rates of nest building and cell production in the warm, rainy season. The trap-nests used by the females ranged from 117 to 467 mm in length and 3.1 to 16.6 mm in diameter. All nests showed deep plugs and a vestibular cell was found in 37% of the complete nests. The number of cells per nest ranged from one to 12. Females were larger than males, emerged from longer cells and their cocoons were significantly larger. A secondary 1:1 sex ratio was found in Araras and Rifaina. No correlation was observed between the diameter of the trap-nest and sex ratio. Males were usually oviposited in the first brood cells. Male and female developmental time from egg to adult was longer in the cold, dry season. Trypoxylon aurifrons provisioned their nests mainly with orb-spiders from the family Araneidae. The most important mortality factor was the death of immature forms, probably due to development failure. The most important parasitoid was Melittobia sp.
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The plant architecture hypothesis predicts that variation in host plant architecture influences insect herbivore community structure, dynamics and performance. In this study we evaluated the effects of Macairea radula (Melastomataceae) architecture on the abundance of galls induced by a moth (Lepidoptera: Gelechiidae). Plant architecture and gall abundance were directly recorded on 58 arbitrarily chosen M. radula host plants in the rainy season of 2006 in an area of Cerrado vegetation, southeastern Brazil. Plant height, dry biomass, number of branches, number of shoots and leaf abundance were used as predicting variables of gall abundance and larval survival. Gall abundance correlated positively with host plant biomass and branch number. Otherwise, no correlation (p > 0.05) was found between gall abundance with shoot number or with the number of leaves/plant. From a total of 124 galls analyzed, 67.7% survived, 14.5% were attacked by parasitoids, while 17.7% died due to unknown causes. Larvae that survived or were parasitized were not influenced by architectural complexity of the host plant. Our results partially corroborate the plant architecture hypothesis, but since parasitism was not related to plant architecture it is argued that bottom-up effects may be more important than top-down effects in controlling the population dynamics of the galling lepidopteran. Because galling insects often decrease plant fitness, the potential of galling insects in selecting for less architectural complex plants is discussed.
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Vespas do gênero Trypoxylon apresentam comportamento solitário e aprovisionam seus ninhos de forma massiva com aranhas paralisadas. Algumas espécies utilizam cavidades preexistentes para nidificação, o que facilita sua amostragem e estudo. Neste trabalho, dados sobre a biologia de nidificação de quatro espécies de Trypoxylon (Trypargilum) - T. rogenhoferi, T. lactitarse, T. aurifrons e T. nitidum - são apresentados. As espécies foram amostradas por meio de ninhos-armadilha durante três anos em Araras e dois anos em Rifaina e São Carlos (São Paulo). As localidades de estudo foram subdivididas em sítios de amostragem. Foram obtidos 2.698 ninhos de himenópteros solitários, dos quais 2.268 foram fundados por espécies de Trypoxylon. Intensa atividade de nidificação foi observada principalmente na estação quente e chuvosa (outubro-março). Os ninhos-armadilha utilizados para nidificação pelas diferentes espécies apresentaram dimensões significativamente diferentes. A família de aranhas mais utilizada para aprovisionamento foi Araneidae; no entanto, as espécies de vespas diferiram quanto às espécies forrageadas. O principal parasitóide das quatro espécies foi Melittobia, mas indivíduos das famílias Chrysididae, Ichneumonidae, Chalcididae e Sarcophagidae também foram verificados. Observou-se que as espécies de Trypoxylon coexistem temporalmente e que nas três localidades cada espécie nidificou com maior freqüência em um sítio particular, sugerindo uma ocupação diferencial do habitat. A partição do habitat aparentemente homogêneo pode ser resultado de "competição aparente" mediada por inimigos naturais comuns.
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A riqueza de insetos galhadores é maior nas latitudes intermediárias em hábitats quentes e com vegetação esclerófila sob estresse hídrico e de nutrientes. Em regiões tropicais, os campos rupestres são indicados como hábitats ricos em espécies de insetos galhadores. Neste trabalho, foram descritas as galhas induzidas por insetos e suas plantas hospedeiras na porção sul da Cadeia do Espinhaço, sudeste do Brasil. Foram selecionados 60 sítios em seis regiões ao longo na porção sul da Cadeia do Espinhaço no estado de Minas Gerais. Em cada sítio 100 plantas foram amostradas totalizando 6.000 plantas censuradas ao longo de um gradiente altitudinal de 668 a 1860m. Foram encontrados 241 morfotipos de galhas em 142 espécies de plantas distribuídas em 29 famílias e de um total de 384 espécies de plantas amostradas. As famílias mais ricas em espécies de insetos galhadores foram Asteraceae (42%), principalmente espécies do gênero Baccharis. A maior parte das galhas (85%) foi induzida por insetos da família Cecidomyiidae seguidos por Lepidoptera (4%) e Homoptera (3%). Os ramos foram os órgãos mais freqüentemente atacados (72%) enquanto que os morfotipos mais comuns foram o elíptico (37%) e o globóide (36%). A espécie de planta hospedeira que apresentou mais morfotipos de galhas foi Baccharis pseudomyriocephala com 10 galhas distintas. Este estudo sustenta a afirmativa que campos rupestres apresentam uma elevada riqueza em espécies de insetos galhadores.