686 research outputs found

    Influence of trichomes on attractiveness and ovipositional preference of Bemisia tabaci (Genn.) B biotype (Hemiptera: Aleyrodidae) on tomato genotypes

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    Brazil is one of the world's largest tomato producer, but considerable part of the production is lost due to the attack of Bemisia tabaci (Genn.) B biotype. Resistant germoplasm plants can be an important method for B. tabaci control in integrated pest management approaches. The attractiveness and ovipositional preference of B. tabaci for 17 tomato genotypes were evaluated in a free-choice test. Trials were set up in a randomized block design with ten replicates. Each replicate (one tomato plant per pot) was placed in a cage (80 x 50 x 50 cm) and infested with 1,000 adults during four days. Linear correlation tests were applied between the number of insects and eggs and number of trichomes in each tomato genotype. LA716, LA444-1 and PI134418 genotypes were the least attractive, while the 'Santa Clara' was the most attractive; PI134417 trapped the largest number of adults. LA716 genotype (4.1 eggs/leaflet and 2.1 cm²/eggs per leaflet) was the least preferred for whitefly oviposition; NAV1062, 'Fanny', LA1335, 'Santa Clara' and IAC294 were the most preferred genotypes. The glandular trichomes density was negatively correlated with whitefly's attractiveness and oviposition per leaflet and per leaf, and positively with the number of trapped insects. The non-glandular trichomes density was negatively correlated with the number of trapped insects and positively with whitefly's oviposition per cm²/leaflet andper cm²/leaf. LA716 had high antixenosis level (ovipositional nonpreference) toward B. tabaci B biotype related with type IV glandular trichome.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Risk-Informed design process of the IRIS reactor

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    Westinghouse is currently conducting the pre-application licensing of the International Reactor Innovative and Secure (IRIS). The design philosophy of the IRIS has been based on the concept of Safety-by-DesignTM and within this framework the PSA is being used as an integral part of the design process. The basis for the PSA contribution to the design phase of the reactor is the close iteration between the PSA team and the design and safety analysis team. In this process the design team is not only involved in the initial phase of providing system information to the PSA team, allowing in this way the identification of the high risk scenarios, but it is also receiving feedback from the PSA team that suggests design modification aimed at reaching risk-related goals. During the first iteration of this process, the design modifications proposed by the PSA team allowed reducing the initial estimate of Core Damage Frequency (CDF) due to internal events from 2E-6/ry to 2E-8/ry. Since the IRIS design is still in a development phase, a number of assumptions have to be confirmed when the design is finalized. Among key assumptions are the success criteria for both the accident sequences analyzed and the systems involved in the mitigation strategies. The PSA team developed the initial accident sequence event trees according to the information from the preliminary analysis and feasibility studies. A recent coupling between the RELAP and GOTHIC codes made possible the actual simulation of all LOCA sequences identified in the first draft of the Event Trees. Working in close coordination, the PSA and the safety analysis teams developed a matrix case of sequences not only with the purpose of testing the assumed success criteria, but also with the perspective of identifying alternative sequences developed mainly by relaxing the extremely conservative assumptions previously made. The results of these simulations, bounded themselves with conservative assumptions on the Core Damage definition, suggested two new versions of the LOCA Event Tree with two possible configurations of the Automatic Depressurization System. The new CDF has been evaluated for both configurations and the design team has been provided with an additional and risk-related perspective that will help choosing the design alternative to be implemented

    Biological aspects of Bemisia tabaci (Genn.) B biotype (Hemiptera: Aleyrodidae) on six bean genotypes

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    A mosca-branca é um dos insetos mais prejudiciais à cultura do feijoeiro, devido principalmente à intensa sucção de seiva e à transmissão do vírus do mosaico dourado. O uso de cultivares resistentes ao inseto é uma ferramenta importante no seu controle. Ensaios foram conduzidos em laboratório, avaliando-se aspectos biológicos de Bemisia tabaci biótipo B para os seguintes genótipos de feijoeiro: Arc 3s, Arc 5s, G13028, G11056, Arc 1 e Porrillo 70. As plantas (estágio IV-1) foram infestadas por moscas-brancas durante um dia e os ovos e ninfas foram observados até a emergência dos adultos. A longevidade e a fecundidade dos insetos emergidos também foram avaliadas. Ninfas alimentadas no genótipo Arc 3s (26,5 dias) tiveram o período de desenvolvimento mais longo, seguidas de G11056 (25,9 dias) e G13028 (25,3 dias). Houve um alongamento de 5,5 dias no período de desenvolvimento dos insetos em Arc 3s quando comparado com Porrillo 70. Altas taxas de mortalidade das ninfas nos genótipos Arc 3s e G11056 (94,7 e 83,1%, respectivamente) indicam que tais materiais podem apresentar resistência do tipo não-preferência para alimentação e/ou antibiose. Assim, embora a longevidade e a fecundidade do inseto não tenham sido afetadas quando criado nos genótipos resistentes (Arc 3s, G11056, G13028 e Arc 5s), sugere-se que tais materiais sejam utilizados em programas de melhoramento de feijoeiro visando à resistência a B. tabaci biótipo B.The silverleaf whitefly is one of the most harmful pests that attack bean crops, mainly for extracting large quantities of phloem sap and transmitting the bean golden mosaic virus. Resistant germoplasm plants can be an important method for controlling this pest. The biological aspects of Bemisia tabaci B biotype on bean (Phaseolus vulgaris) genotypes were evaluated. The tests were conducted under laboratory conditions, with the following genotypes: Arc 1, Arc 3s, Arc 5s, G13028, G11056 and Porrillo 70. The bean plants in a stage IV-1 were infested during one day with silverleaf whiteflies. Afterwards the eggs and nymphs were observed until adult emergence. Longevity and fecundity of emerged insects were also evaluated. The longest development time occurred for nymphs fed on Arc 3s genotype (26.5 days), following by G11056 (25.9 days) and G13028 (25.3 days). The development period was 5.5 days longer in Arc 3s when compared with Porrillo 70. Also, the wild genotypes Arc 3s and G11056 showed higher mortality rates (94.7% and 83.1%, respectively), which may suggest antibiosis and/or feeding nonpreference resistance type. For this reason, although longevity and fecundity were not influenced when the whitefly fed on resistant genotypes (Arc 3s, G11056, G13028 and Arc 5s), those genotypes can be used for bean breeding program towards B. tabaci B biotype

    Does Co-Location Accelerate Knowledge Outflows from FDI? The Role of MMC Subsidiaries' Technology Sourcing Strategies

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    Despite the strategic importance of the knowledge outflows from FDI for local firms’ competitiveness, no study has focused on the speed at which this phenomenon takes place. However, this issue is crucial since the speed at which firms absorb external knowledge influences the time they need to carry out subsequent innovations, their ability to adapt to external changes and enter new markets, thus ultimately affecting their chances to achieve a competitive advantage. This paper tries to fill this gap, by investigating the temporal patterns of knowledge outflows between foreign subsidiaries and firms located in host-regions. Combining International Business literature with insights on Innovation Strategy, we provide evidence on the timing of this phenomenon, and discuss the role played by multinational firms’ technology sourcing strategies

    Elementary art education : an expendable curriculum?

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    This ethnographic study was initiated by the concern that elementary art education is an endangered subject, not only marginalised but expendable. This concern was based on informal conversations with pre- and in-service teachers and observations during pre-service teacher evaluations in elementary schools in Ontario, Canada. From these conversations and observations, it seemed that the emphasis in elementary schools is on core subjects with anything else deemed to provide balance alongside initiatives to improve literacy, numeracy, character, and inclusion. The school day is teeming with subjects and initiatives and the resulting crowded curriculum may be affecting teaching and learning in non-core subjects, such as art, negatively. In addition to such external issues are individual challenges faced by generalist teachers with little or no background in visual arts. These teachers’ lack of comfort with art might, I surmised at the start of this study, impede the effective planning, implementation, and assessment of art education. To understand what impacts art education, specifically visual arts instruction, I used a variety of interpretive enquiry methods to interrogate what makes art in elementary schools a vulnerable if not an expendable subject. Initially seeking to find out if art was expendable, I went beyond this to explore perceptions of teachers on teaching art through a localised small-scale study involving 19 elementary teachers in two school boards in north-eastern Ontario. I conducted interviews, recorded observations, and read related documents to answer my research questions, which were as follows: Why is art education important, or not, for students, educators, parents, and other stakeholders? Is art jettisoned in favour of implementing other policies and curricular subjects? Do teachers use other programmes and initiatives as an excuse not to teach art? How do teachers feel about teaching art? Is art expendable? Nussbaum’s (1997) capacities (critical self-examination, connectedness with the world, narrative imagination, scientific understanding) provide the theoretical framework for the study, support the analysis of the state of art education, and help defend its importance at the elementary level. Possible barriers to effective art education (history, policy, practice, economics, geography) and how they may affect learners’ ability to connect with the capacities through visual arts instruction are also analysed and discussed. Through this study, I found that elementary art education is threatened in the participants’ schools for a number of reasons including external issues (minimal attention to, inconsistent delivery of, and poor funding for the mandated art curriculum; a high focus on literacy, numeracy, and other initiatives) and internal issues (discomfort with teaching art; wide range of concepts of art). The study concludes with concerns regarding overall problems with miscommunication and disconnection that threaten effective elementary art education. Recommendations for addressing external and internal issues, and these overall problems are outlined, along with plans to improve art education in pre-service teacher education, in-service practice, and the world beyond the classroom.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    A bibliometric review of financial market integration literature

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    We undertake a meta-literature review on the topic of financial market integration (FMI), covering 260 articles from 1981 to 2021. Our review consists of quantitative analysis of bibliometric citations concomitant with qualitative analysis of content, towards a goal of identifying primary research streams and proposing directions for future research. We identify five research groups: (1) portfolio diversification with financial market integration; (2) general equity market integration; (3) financial market linkage with respect to crises and events; (4) time-varying financial market integration; and (5) co-movements and spillovers between commodities and financial markets; as well as present a wide array of future research directions. We conduct an extensive review of FMI literature, answering several questions: (1) What is the domain of FMI research?; (2) What are the influential aspects of top journals and authors, and the characteristics of the most studied topics?; (3) What are the past and current key research streams in FMI literature?; and (4) What are the substantial future relevant research questions to explore regarding FMI? Given the ongoing attention on financial market integration by both academicians and policy makers, our results should be of great interest

    Nutritional controlled preparation and administration of different tomato purées indicate increase of β-carotene and lycopene isoforms, and of antioxidant potential in human blood bioavailability: A pilot study

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    The isoforms of lycopene, carotenoids, and their derivatives including precursors of vitamin A are compounds relevant for preventing chronic degenerative diseases such as cardiovascular diseases and cancer. Tomatoes are a major source of these compounds. However, cooking and successive metabolic processes determine the bioavailability of tomatoes in human nutrition. To evaluate the effect of acute/chronic cooking procedures on the bioavailability of lycopene and carotene isoforms in human plasma, we measured the blood levels of these compounds and of the serum antioxidant potential in volunteers after a meal containing two different types of tomato sauce (rustic or strained). Using a randomized cross-over administration design, healthy volunteers were studied, and the above indicated compounds were determined by HPLC. The results indicate an increased bioavailability of the estimated compounds and of the serum antioxidant potential with both types of tomato purée and the subsequently derived sauces (the increase was greater with strained purée). This study sheds light on the content of nutrient precursors of vitamin A and other antioxidant compounds derived from tomatoes cooked with different strategies. Lastly, our study indicates that strained purée should be preferred over rustic purée

    Hydrogen charging in nickel and iron and its effect on their magnetic properties

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    The current study was undertaken to explore the possibility of detecting hydrogen cavitation in magnetic materials through magnetic propertymeasurements. It is known that dissolved hydrogen in a material causes microvoids. These voids may affect the structure‐sensitive magnetic properties such as coercivity and remanence. In this study, hydrogen was introduced into nickel and iron by two processes, namely thermal charging and cathodic charging. The effect on the magnetic properties was measured. In addition, the variation of the magnetic properties with porosity was studied

    Body composition in Italian and Danish women

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    Summary The objective of this cross-sectional study was to compare the body composition and fat distribution measured by dual energy X-ray absorptiometry (DPX, Lunar) in different age decades of agematched Danish and Italian women. The subjects comprised 133 healthy Italian women (age 20± 60 years) age-matched to a representative sub-sample of healthy Danish women (n 375). Total and abdominal body fat tissue mass were measured by dual-energy X-ray absorptiometry. Italian women were shorter and fatter compared with age-matched Danish women, but in middle-age, had a less abdominal fat distribution. There was no difference in total body bone mineral density
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