Lie Symmetries and Criticality of Semilinear Differential Systems

We discuss the notion of criticality of semilinear differential equations and systems, its relations to scaling transformations and the Noether approach to Pokhozhaev's identities. For this purpose we propose a definition for criticality based on the S. Lie symmetry theory. We show that this definition is compatible with the well-known notion of critical exponent by considering various examples. We also review some related recent papers

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

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

5-FU targets rpL3 to induce mitochondrial apoptosis via cystathionine-b-synthase in colon cancer cells lacking p53

Recent findings revealed in cancer cells novel stress response pathways, which in response to many chemotherapeutic drugs causing nucleolar stress, will function independently from tumor protein p53 (p53) and still lead to cell cycle arrest and/or apoptosis. Since it is known that most cancers lack functional p53, it is of great interest to explore these emerging molecular mechanisms. Here, we demonstrate that nucleolar stress induced by 5-fluorouracil (5-FU) in colon cancer cells devoid of p53 leads to the activation of ribosomal protein L3 (rpL3) as proapoptotic factor. rpL3, as ribosome-free form, is a negative regulator of cystathionine-β-synthase (CBS) expression at transcriptional level through a molecular mechanism involving Sp1. The rpL3-CBS association affects CBS stability and, in addition, can trigger CBS translocation into mitochondria. Consequently apoptosis will be induced through the mitochondrial apoptotic cell death pathway characterized by an increased ratio of Bax to Bcl-2, cytochrome c release and subsequent caspase activation. It is noteworthy that silencing of CBS is associated to a strong increase of 5-FU-mediated inhibition of cell migration and proliferation. These data reveal a novel mechanism to accomplish p53-independent apoptosis and suggest a potential therapeutic approach aimed at upregulating rpL3 for treating cancers lacking p53

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