12,377 research outputs found
Field host range of Apanteles opuntiarum (Hymenoptera: Braconidae) in Argentina, a potential biocontrol agent of Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America
Field exploration in Argentina for cactophagous lepidopteran hosts parasitized by the recently described braconid parasitoid Apanteles opuntiarum MartĂnez & Berta (Hymenoptera: Braconidae) revealed a host range restricted to Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) and C. doddi. Field collections of cactophagous larvae parasitized by the congeneric and sympatric parasitoid A. alexanderi included the host species C. bucyrus, Sigelgaita nr. chilensis, Tucumania sp., Tucumania tapiacola and Salambona sp. If a narrow host range for A.opuntiarum is confirmed in quarantine with North American cactus-feeding species, then this parasitoid could be released as a biological control agent for C. cactorum with little or no risk to non-target species.Las exploraciones de campo en Argentina de larvas hospedadoras cactĂłfagas parasitadas por Apanteles opuntiarum MartĂnez & Berta (Hymenoptera: Braconidae), un bracĂłnido recientemente descripto, revelaron un espectro de hospedadores restringido a Cactoblastis cacÂtorum (Berg) (Lepidoptera: Pyralidae) y C. doddi. Las colecciones de campo de larvas cactĂłfagas parasitadas por la especie congenĂ©rica y simpátrica A. alexanderi identificaron a C. bucyrus, Sigelgaita nr. chiÂlensis, Tucumania sp., Tucumania tapiacola y Salambona sp. como esÂpecies hospedadoras. Si se confirma en cuarentena el estrecho rango de hospedadores de A. opuntiarum sobre especies norteamericanas que se alimentan de cactus, podrĂa ser liberado como agente de conÂtrol biolĂłgico de C. cactorum, con bajo riesgo o ninguno a especies no blanco.Fil: Varone, Laura. FundaciĂłn para el Estudio de Especies Invasivas; ArgentinaFil: Logarzo, Guillermo Alejandro. FundaciĂłn para el Estudio de Especies Invasivas; ArgentinaFil: Martinez, Juan Jose. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Navarro, Fernando. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de EntomologĂa; ArgentinaFil: Carpenter, James E.. United States Department of Agriculture; Estados UnidosFil: Hight, Stephen D.. United States Department of Agriculture; Estados Unido
Microfoundations of Problem Solving: Attentional Engagement Predicts Problem-Solving Strategies
Organizations use a plethora of methods and tools to help their members solve problems effectively. Yet the specifics of how individuals solve problems remain largely unexplored. We propose and test a cognitive model of problem solving that integrates dual process theories into the attention-based view. The model suggests that diverse problem-solving strategies emerge in response to how individuals deliberate. Three studies provide observational and causal evidence in support of our model. The first study explores the strategies managers use to solve problems. We use think-aloud protocols combined with content, sequence, and cluster analyses to extract the key differences in how experienced managers solve problems. Two problem-solving strategies emerge from the data: one emphasizes mental activities related to framing, and the other emphasizes mental activities related to implementation. In the second study, we use a mixed factorial experimental design and mouse-tracking analysis to uncover the causal mechanism that explains the emergence of these two strategies. We then retest our hypotheses in a third, preregistered, study. We find that manipulating attention toward mental activities related to framing increases deliberation aimed at restructuring the problem elements. In contrast, directing attention toward mental activities related to implementation increases deliberation on the potential contingencies and consequences of the solution. Our findings provide empirical evidence about how problems are actually solved and support the idea that attentional processes are malleable enough to affect the choice of problem-solving strategies
Diffeomorphisms, Noether Charges and Canonical Formalism in 2D Dilaton Gravity
We carry out a parallel study of the covariant phase space and the
conservation laws of local symmetries in two-dimensional dilaton gravity. Our
analysis is based on the fact that the Lagrangian can be brought to a form that
vanishes on-shell giving rise to a well-defined covariant potential for the
symplectic current. We explicitly compute the symplectic structure and its
potential and show that the requirement to be finite and independent of the
Cauchy surface restricts the asymptotic symmetries.Comment: 14 pages, latex with psfig macro, one figur
High frequency mechanical excitation of a silicon nanostring with piezoelectric aluminum nitride layers
A strong trend for quantum based technologies and applications follows the
avenue of combining different platforms to exploit their complementary
technological and functional advantages. Micro and nano-mechanical devices are
particularly suitable for hybrid integration due to the easiness of fabrication
at multi-scales and their pervasive coupling with electrons and photons. Here,
we report on a nanomechanical technological platform where a silicon chip is
combined with an aluminum nitride layer. Exploiting the AlN piezoelectricity,
Surface Acoustic Waves are injected in the Si layer where the material has been
localy patterned and etched to form a suspended nanostring. Characterizing the
nanostring vertical displacement induced by the SAW, we found an external
excitation peak efficiency in excess of 500 pm/V at 1 GHz mechanical frequency.
Exploiting the long term expertise in silicon photonic and electronic devices
as well as the SAW robustness and versatility, our technological platform
represents a strong candidate for hybrid quantum systems
Free Fields for Chiral 2D Dilaton Gravity
We give an explicit canonical transformation which transforms a generic
chiral 2D dilaton gravity model into a free field theory.Comment: LaTeX file, 4 pages, to appear in Phys. Rev.
Le défigement linguistique comme recours stylistique, et les écueils traductologiques induits de l’espagnol vers le français
The man\u27s gaze transcends reality to so often cosmetic purposes. Referring to literature, here we will only tackle the part of the narrative creation which are the metaphorical interpretation and its derivatives to linger over this other type of diversion realized by the language de-fossilization in its phraseology and lexical applications, leading to many puns.
The translator must accommodate to this sign of discursive freedom of authors, establishing semantic and semiotic relations of collusion between the source language and the target language. This is what we will develop on the basis of about ten illustrations from Hispanic literature. For each case, we will emphasize the intuitive logic of the original find, to propose its transfer in French, pointing that through a translatological "intuitivo-cognitive" posture, the translator can develop his very own creativity, a true wager of literary faithfulness
Scaling-up climate services with users in Latin America
Latin America farmers are highly vulnerable to climate variability, with crop losses observed throughout the region on a virtually annual basis. For instance, as indicated by the United Nations’ Food and Agriculture Organization (FAO) and World Food Program (WFP), the 2014–2017 drought conditions in Central America affected over 3.5 million people in Guatemala, Honduras and El Salvador. At the same time, local stakeholders and farmers generally have limited access to existing climate and forecast information, do not have sufficient capacities to understand the climate information and/or mechanisms to relate this information to the impact that climate variations can generate at a local level. This precludes the translation of information into actionable knowledge, and therefore into action.
In this study, we describe a process through which scientists and strategic partners have co-developed, tested and scaled out an approach to assess, co-produce, translate and transfer climate information to enable agricultural decision making –the Local Technical Agroclimatic Committees (LTAC). LTACs allow open and clear dialogues about climate variations at multiple timescales, how these can affect crops, and the design of measures to reduce crop loss, particularly providing agronomic recommendations to farmers. We systematically describe the process of evidence generation, creation, partner engagement, scaling up, and monitoring of the approach throughout Latin America.
Currently, 35 LTACs exist in 9 Latin American countries, engaging more than 250 public and private institutions, increasing the resilience and food security of an estimated 330,000 farmers, and potentially transforming how Latin American farmers manage climate risk. The study illustrates changes in institutional and farmers' capacities to co-produce, translate and use climate information and explores how better climate and crop prediction models can effectively underpin this process. We show how strategic alliances with farmer organizations, national public, and private and regional climate outlook forums help deliver improved and accurate climate information to users. Finally, we document how LTACs and their integration with other local-scale processes have led to changes in farmers’ management practices to take better advantage of good climatic conditions or avoid losses
Integrable models and degenerate horizons in two-dimensional gravity
We analyse an integrable model of two-dimensional gravity which can be
reduced to a pair of Liouville fields in conformal gauge. Its general solution
represents a pair of ``mirror'' black holes with the same temperature. The
ground state is a degenerate constant dilaton configuration similar to the
Nariai solution of the Schwarzschild-de Sitter case. The existence of
solutions and their relation with the solution given by the 2D
Birkhoff's theorem is then investigated in a more general context. We also
point out some interesting features of the semiclassical theory of our model
and the similarity with the behaviour of AdS black holes.Comment: Latex, 16 pages, 1 figur
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