A new critical curve for the Lane-Emden system

We study stable positive radially symmetric solutions for the Lane-Emden system $-\Delta u=v^p$ in $\R^N$, $-\Delta v=u^q$ in $\R^N$, where $p,q\geq 1$. We obtain a new critical curve that optimally describes the existence of such solutions.Comment: 13 pages, 1 figur

Nutrição mineral de leguminosas tropicais II. Carências nutricionais em Leucaena leucocephala (Lamb.) de Wit

The present work was carried out in order to study: a) identification of deficiencies symptoms of N, P, K, Ca, Mg, S, and B; b) the effects the deficiency of each macronutrient and boron on the chemical composition of the plants. Young Leucaena plants were grown in pots containing pure quartz. Several times a day the plants were irrigated by percolation with nutrient solutions. The treatments were: complete solution and deficient solutions, in which each of the macronutrients or boron was omitted. Malnutrition symptoms appeared after 200 days of cultivation. Symptoms of nutrition were observed for all treatments. The concentration of the elements in the leaves of plants cultivated under normal and under deficient conditions were: N% - 3.51-2.79; P% - 0,14-0,11; K% - 2.75-1.33; Ca% - 1.11-0.41; Mg% - 0.42-0.18; S% - 0.22-0.11; B ppm - 127-25.Plantas de Leucanena leuoocephala (lamb.) De Wit foram submetidas a tratamentos em soluções nutritivas carentes em N, P. K, Ca, Mg, S e B com o objetivo de se obter o quadro sintomatológivo das carências, assim como teores dos elementos na raiz, caule e folhas. Os sintomas apareceram após 200 dias de cultivo e foram de difícil caracterização. Os teores encontrados nas folhas de plantas com sintomas enormais foram respectivamente: N%-2,77-3,51; P% - 0,11-0,14; K% - 1,33 - 2,75 ; Ca% - 0,41-1,11; Mg% - 0,18-0,42; S% -0,11-0,22; B ppm - 25-127

Polinização da aboboreira

The present paper deals with studies related to pollination of Cucurbita pepo L. in the State of S. Paulo, Brazil. The following results were obtained: 1.° - The ratio of female flowers to male flowers openig at the same day was 1:17,7. 2.º - The opening of the female flowers and observed to occur before the sun rises. Closing begins at 9 A.M. and is finished by 11 A. M. 3.° - With respect to pollinizating insects, Trigona (Trigona) ruficrus Latr.) and Apis, mellifera L. constitute the most important species. 4.° - Due to the phenomenon of parthenocarpy no frutification was observed. 5.º - The sugar concentration of the nectar was observed to average 39,7% and 40,6%. 6.º - The pollination of Cucurbita pepo L. is only by insects.Os autores planejaram um experimento com a finalidade de esclarecer vários problemas ligados com a polinização da aboboreira. Para êsse fim, foi organizada uma cultura com a variedade Brasileira. O campo constou de 48 covas, cada qual com uma planta, distanciadas de 2m. As plantas foram conduzidas em caramanchões de 1m de altura, separados por corredores de 3 m. Cada caramanchão abrangeu 4 plantas. Com a finalidade de se estudar a polinização na ausência de insetos, três caramanchões foram cobertos com telas de "nylon". Os resultados das pesquisas, foram os seguintes: 1.° - A proporção de flôres femininas e masculinas abertas no mesmo dia foi de 1:17,7. 2.° - A abertura das flôres se dá em plena madrugada. 3.° - As abelhas Irapuás (Trigona (Trigona) ruficrus Latr.) e as Apis mellifera L. constituiram os principais insetos polinizadores da aboboreira. 4.° - Não foi constatado o fenômeno partenocárpico na aboboreira. 5.° - As concentrações médias dos sólidos do néctar das flôres de abóbora, em dois dias, de medições com o refratômetro de campo Huet foram, respectivamente, de 39,7% e 40,6%. 6.° - Foi constatado que na ausência de insetos não houve frutificação. Os frutos provenientes de flôres polinizadas pelos insetos alcançaram um rápido desenvolvimento, estando em condições de serem consumidos como aboborinhas, após o quarto dia de formação

Detección de Xanthomonas arboricola pv. pruni mediante inmunocaptura magnética y PCR en tiempo real: póster

PublishedTrabajo financiado por el Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), proyecto RTA2011-00140-C03-02 y por la Red CYTED FRUT-SAN 112RT044

Asymptotic behaviour of a semilinear elliptic system with a large exponent

Consider the problem \begin{eqnarray*} -\Delta u &=& v^{\frac 2{N-2}},\quad v>0\quad {in}\quad \Omega, -\Delta v &=& u^{p},\:\:\:\quad u>0\quad {in}\quad \Omega, u&=&v\:\:=\:\:0 \quad {on}\quad \partial \Omega, \end{eqnarray*} where $\Omega$ is a bounded convex domain in $\R^N,$ $N>2,$ with smooth boundary $\partial \Omega.$ We study the asymptotic behaviour of the least energy solutions of this system as $p\to \infty.$ We show that the solution remain bounded for $p$ large and have one or two peaks away form the boundary. When one peak occurs we characterize its location.Comment: 16 pages, submmited for publicatio

Alternativas técnicas para el almacenamiento de calabacitas Butternut o coreanas (Cucurbita moschata Duch.)

p.61-68El objetivo de este trabajo fue desarrollar tecnología para mantener la calidad comercial de calabacitas tipo buttemut o coreanas (Cucúrbita moschata Duch.) y así alcanzar períodos del año de mayores precios. Para disminuir la deshidratación y reducir las podredumbres, principales causas de deterioro en este producto, se evaluó el uso de técnicas como embolsado, aplicación de cera, cal y almacenamiento refrigerado, solas o combinadas. A la cosecha y cada 4 semanas hasta alcanzar seis meses de conservación, se efectuaron determinaciones de componentes de la calidad como porcentaje de pérdida de peso, firmeza, color, contenido de sólidos solubles y grado de ahuecado interno, además se registraron las podredumbres y los agentes causales. Exceptuando los tratamientos que incluyeron el uso de bolsas de polietileno, no se encontraron ventajas del uso de las técnicas probadas (cera, cal, cera + cal, almacenamiento refrigerado) con respecto al testigo en ninguna de las variables medidas a los 5 meses de almacenamiento. A los 4 meses de poscosecha, los frutos tratados con cera superaron en retención de peso al testigo y a los tratados con cal. No se observaron podredumbres durante las primeras 16 semanas de evaluación; posteriormente, el uso de frío y la combinación del uso de cal y embolsado con polietileno evitaron el desarrollo de enfermedades. En general, la enfermedad más frecuente fue la causada por Didymella bryoniae, mientras que en los tratamientos que involucraron el uso de bolsas de polietileno predominó el desarrollo de Fusarium spp. El uso de bolsas de polietileno de alta densidad constituyó una barrera efectiva al vapor de agua, reduciendo substancialmente la deshidratación y la pérdida de la calidad durante todo el experimento. La conservación en cámara frigorífica (13ºC) evitó los problemas sanitarios pero fue ineficiente en el mantenimiento de la calidad de los frutos

Preliminary definition of CORTEX interaction model

As scheduled in the Technical Annex, WP2-D3 comprises work on the basic communication abstractions and the context and environmental awareness. It is structured in an introduction, providing a short survey of the content and four technical chapters. Chapter 2 describes the notion of event channels as a basic middleware abstraction of the interaction model. The concept of event channels accommodates an event-based, generative, many-to-many, anonymous communication model. It contributes to the resolution of the trade-off between autonomy and the need of coordination. Rather than explicitly coordinating actions by transferring control, an event channel allows interaction via a shared data space, thereby maintaining the autonomy of components. A comparison with alternative schemes is presented in chapter 3. Here, the impact of the interaction scheme on the modelling and implementation of a complex robotic application is analysed. It provides additional arguments in favour of a publisher/subscriber communication architecture. One of the challenges in CORTEX is to integrate the cooperation of components through the environment into the general interaction concept. The sensor capabilities of the sentient components and their ability to interact with the environment open new ways of cooperation. A mechanism called Stigmergy which is borrowed from biology and discussed in the CORTEX context is presented in chapter 4. Any activity which is carried out in the physical world needs to adapt to the pace and dependability requirements dictated by the environment. In technical terms this means that non-functional properties of the system, as timeliness and reliability of operation have to be included. These Quality of Service (QoS) attributes have to be guaranteed even in an environment where unanticipated dynamic change is one of the inherent properties. Chapter 5 introduces an adaptive QoS mechanism based on a reliable and timely system service. This service, called the Timely Computing Base (TCB) is able to monitor distributed system activities and to provide an "early warning system" for temporal and functional failures. The TCB thus provides part of the context and environmental awareness needed for adaptatio

Five types of blow-up in a semilinear fourth-order reaction-diffusion equation: an analytic-numerical approach

Five types of blow-up patterns that can occur for the 4th-order semilinear parabolic equation of reaction-diffusion type u_t= -\Delta^2 u + |u|^{p-1} u \quad {in} \quad \ren \times (0,T), p>1, \quad \lim_{t \to T^-}\sup_{x \in \ren} |u(x,t)|= +\iy, are discussed. For the semilinear heat equation $u_t= \Delta u+ u^p$, various blow-up patterns were under scrutiny since 1980s, while the case of higher-order diffusion was studied much less, regardless a wide range of its application.Comment: 41 pages, 27 figure

La técnica y la política. Perspectivas desde América Latina

Este nuevo libro colectivo recoge los trabajos del grupo de investigación de Filosofía de la PUCE, elaborados entre 2019 y 2020. El tema elegido, Tecnología y política, define una de las problemáticas contemporáneas más relevantes dentro del trabajo académico. Como en ocasiones anteriores, cada autor plantea contextos de lectura diversos; los aportes recorren un escenario complejo, resultado de los caminos que cada uno ha elegido para consolidar su propia reflexión a partir de los proyectos de escritura de tesis de posgrado y de investigaciones desarrolladas tanto en universidades europeas como americanas. Sin embargo, el punto de encuentro está dado en la perspectiva y en las condiciones que determinan la posibilidad de proponer un pensamiento crítico y propositivo desde América Latina