► Radio-emission (MHz–GHz) from hadronic showers in ice. ► Study of influence of hadrons on the emitted signal. ► Parameterizations of electric field in the frequency domain.
The Cherenkov radio ...pulse emitted by hadronic showers of energies in the EeV range in ice is calculated for the first time using full three dimensional simulations of both shower development and the coherent radio pulse emitted as the excess charge develops in the shower. A Monte Carlo, ZHA
ireS, has been developed for this purpose combining the high energy hadronic interaction capabilities of AIRES, and the dense media propagation capabilities of TIERRAS, with the precise low energy tracking and specific algorithms developed to calculate the radio emission in ZHS. A thinning technique is implemented to allow the simulation of radio pulses induced by showers up to 10
EeV in ice. The code is validated comparing the results for electromagnetic and hadronic showers to those obtained with GEANT4 and ZHS codes. The contribution to the pulse of other shower particles in addition to electrons and positrons, mainly protons, pions and muons, is found to be below 3% for 10
PeV and above proton induced showers. The characteristics of hadronic showers and the corresponding Cherenkov frequency spectra are compared with those from purely electromagnetic showers. The dependence of the spectra on shower energy and high-energy hadronic model is addressed and parameterizations for the radio emission in hadronic showers in ice are given for practical applications.
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•First report on JH levels and mfe gene expression in a highly social non-Apis bee.•JH-titer and mfe expression are higher in nurse bees than in foragers.•JH endocrinology in ...stingless bees is gonadotropic and differs from honey bees.
In social insects, juvenile hormone (JH) has acquired novel functions related to caste determination and division of labor among workers, and this is best evidenced in the honey bee. In contrast to honey bees, stingless bees are a much more diverse group of highly eusocial bees, and the genus Melipona has long called special attention due to a proposed genetic mechanism of caste determination. Here, we examined methyl farnesoate epoxidase (mfe) gene expression, encoding an enzyme relevant for the final step in JH biosynthesis, and measured the hemolymph JH titers for all life cycle stages of Melipona scutellaris queens and workers. We confirmed that mfe is exclusively expressed in the corpora allata. The JH titer is high in the second larval instar, drops in the third, and rises again as the larvae enter metamorphosis. During the pupal stage, mfe expression is initialy elevated, but then gradually drops to low levels before adult emergence. No variation was, however, seen in the JH titer. In adult virgin queens, mfe expression and the JH titer are significantly elevated, possibly associated with their reproductive potential. For workers we found that JH titers are lower in foragers than in nurse bees, while mfe expression did not differ. Stingless bees are, thus, distinct from honey bee workers, suggesting that they have maintained the ancestral gonadotropic function for JH. Hence, the physiological circuitries underlying a highly eusocial life style may be variable, even within a monophyletic clade such as the corbiculate bees.
Traditionally, the depth of maximum shower development
X
max
has been used as a surrogate observable for composition. Here we present the possibility of a new methodology to discriminate between ...light and heavy cosmic-ray primaries on an event-by-event basis. This method is based on comparisons between detected radio signals and Monte Carlo simulations, but instead of first reconstructing
X
max
, we try to infer the cosmic-ray composition directly. We show that a large discrimination efficiency could in principle be reached for zenith angles above θ≃65°, even when some of the typical uncertainties in radio detection are taken into account.
Resumo: A avaliação de ciclo de vida é uma técnica utilizada pela indústria que visa a minimização de possíveis impactos ambientais decorrentes de sua produção. Essas informações ambientais possuem ...potencialidade de serem discutidas em sala de aula. Neste contexto, o objetivo dessa pesquisa é apresentar o conceito de avaliação de ciclo de vida de produtos como uma temática sociocientífica e averiguar quais suas implicações para a formação docente, por meio da teoria de Henry Giroux. A atividade foi realizada com 10 acadêmicos de um curso de licenciatura em química. A investigação possui caráter qualitativo e utilizou o relatório de estágio como instrumento de construção de dados que foi estudado por meio da análise de conteúdo de Laurence Bardin. Com o resultado foi possível perceber que os licenciandos iniciaram um processo de ressignificação do conteúdo de química em direção a um conteúdo global, indissociável, interdisciplinar e essencial para a formação cidadã crítica.
Abstract: Life cycle assessment is a technique used by the industry, which aims to minimize possible environmental impacts resulting from its production. However, in chemistry education, this environmental information has applicability in teacher training. Thus, the purpose in this research is to present the concept of life-cycle assessment as a socio-scientific issue, and to investigate its implications for teacher development, according to Henry Giroux's theory. The research was carried out with 10 Chemistry undergraduate students, and the analysis has a qualitative character, substantiated by reports on academic internship experiences as a tool for data collection. These were analyzed by Laurence Bardin's precepts. As a result, the undergraduate students reframed their experience of chemistry undergraduate studies, towards global, inseparable, interdisciplinary and essential content for critical citizenship education.
Resumo: Este estudo aborda a formação crítica de professores no ensino de Ciências e analisa desafios e potencialidades formativas da realização do Trabalho de Conclusão de Curso (TCC) por futuros ...pedagogos, na perspectiva da Educação, por meio das questões sociocientíficas, bem como busca estimular e promover, durante este processo, a subjetividade, a criatividade e a autoria dos sujeitos envolvidos. A partir dos conceitos teóricos de Theodor Adorno e dos dados obtidos por meio de notas de campo e de gravações das aulas foram criadas três dimensões: semiformativa, transição e dimensão formativa. Concluímos que a Educação, na perspectiva das questões sociocientíficas, contribuiu para a formação crítica em Ciências da Natureza de estudantes de pedagogia em formação, tanto para atuarem na docência, como no processo formativo da elaboração do TCC. Acreditamos que esta pesquisa também traz contribuições para compreender a construção da autonomia, da criatividade e da valorização da subjetividade na busca pela autoria no trabalho acadêmico.
Abstract: This study addresses the critical education of teachers in Science teaching and analyzes challenges and formative potentials of the Course Completion Work (CCW) done by future educators, from the perspective of Education, through socio-scientific issues. It also seeks to stimulate and promote, during this process, the subjectivity, creativity and authorship of the subjects involved. Based on Adorno’s theoretical concepts, and data obtained through field notes and class recordings, three dimensions were created: the half-education, transition and education dimensions. We conclude that education from the perspective of socio-scientific issues contributed to critical education in Nature Sciences to educators in training, both to act in teaching as well as in the educational process of producing the CCW. We believe that this research also brings contributions to explain the construction of autonomy, creativity and appreciation of subjectivity in the search for authorship in academic work.
We present the calculation of coherent radio pulses emitted by extensive air showers induced by ultra-high energy cosmic rays accounting for reflection on the Earth’s surface. Results have been ...obtained with a simulation program that calculates the contributions from shower particles after reflection at a surface plane. The properties of the radiation are discussed in detail emphasizing the effects of reflection. The shape of the frequency spectrum is shown to be closely related to the angle of the observer with respect to shower axis, becoming hardest in the Cherenkov direction. The intensity of the flux at a fixed observation angle is shown to scale with the square of the primary particle energy to very good accuracy indicating the coherent aspect of the emission. The simulation methods of this paper provide the foundations for energy reconstruction of experiments looking at the Earth from balloons and satellites. They can also be used in dedicated studies of existing and future experimental proposals.
Este ensaio tem como objetivo discutir a importância das questões sociocientíficas como uma possibilidade de implementar em sala de aula um ensino de ciências crítico, que contemple as diferentes ...opiniões dos estudantes e que amplie a compreensão das relações entre ciência e tecnologia, imersas em uma sociedade dominada por interesses econômicos. Para isso, retoma a origem dessa perspectiva de educação no movimento Ciência, Tecnologia e Sociedade (CTS), explica a natureza das questões sociocientíficas e sua presença na mídia, articuladas aos desafios encontrados pelos docentes que decidem trabalhar com temas científicos controversos em suas aulas. Por fim, argumenta que é promissor o estudo de questões sociocientíficas no ensino de ciências a partir dos anos iniciais do Ensino Fundamental.
The fungi 'Lasiodiplodia theobromae' and 'Neofusicoccum parvum' are pathogens responsible for causing dieback disease in mangoes. Studies on the inheritance of resistance to these fungal diseases in ...mango are quite limited. The objective of the present study was to evaluate the inheritance of resistance to dieback disease in three pseudo-F2 progenies to assist in mango breeding programs. Young branches containing young leaves were selected, and suspension of 103 conidia/mL of 'L. theobromae' or 'N. parvum' was sprayed separately. After inoculation, leaves were protected in a plastic wet chamber for 48 hours. The infection was estimated by taking the branches without symptoms/total number of inoculated branches. Plants without disease symptoms in more than 90% of the branches, in three different inoculation periods, were considered as resistant. Keitt, Haden, and Espada cultivars were resistant to both fungi, while 'Tommy Atkins' was susceptible to both pathogens. Monogenic resistance, conferred by recessive alleles, was observed for 'L. theobromae' for the three crossings evaluated, despite the 13:3 segregation detected for 'Keitt' x 'Tommy Atkins'. For 'N. parvum', recessive resistance with 3:1 monogenic segregation was observed in the crossing 'Keitt' x 'Tommy Atkins', and 9:7 epistatic segregation was reported in the crossing 'Haden' x 'Tommy Atkins' and ‘Espada x ‘Tommy Atkins’. The mono or digenic inheritance observed in the present study indicates the possibility of selection in the F2 generation and identification of plants with double resistance to 'L. theobromae' and 'N. parvum' in mango trees.
Over the last decades, radio detection of air showers has been established as a promising detection technique for ultrahigh-energy cosmic rays and neutrinos. Very large or dense antenna arrays are ...necessary to be proficient at collecting information about these particles and understanding their properties accurately. The exploitation of such arrays requires to run massive air-shower simulations to evaluate the radio signal at each antenna position, taking into account features such as the ground topology. In order to reduce computational costs, we have developed a fast computation of the emitted radio signal on the basis of generic shower simulations, called Radio Morphing. The method consists in the calculation of the radio signal of any air-shower by i) a scaling of the electric-field amplitude of a reference air shower to the target shower, ii) an isometry on the simulated positions and iii) an interpolation of the radio pulse at the desired position. This technique enables one to gain many orders of magnitude in CPU time compared to a standard computation. In this contribution, we present this novel tool and explain its methodology. In particular, Radio Morphing will be a key element for the simulation chain of the Giant Radio Array for Neutrino Detection (GRAND) project, that aims at detecting ultra-high-energy neutrinos with an array of 200 000 radio antennas in mountainous regions.
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