Photosynthesis dependent acidification of perialgal vacuoles in theParamedum bursaria/Chlorella symbiosis. Visualization by monensin

After treatment with the carboxylic ionophore monensin theChlorella containing perialgal vacuoles of the greenParamecium bursaria swell. TheParamecium cells remain motile at this concentration for at least one day. The swelling is only observed in illuminated cells and can be inhibited by DCMU. We assume that during photosynthesis the perialgal vacuoles are acidified and that monensin exchanges H+ ions against monovalent cations (here K+). In consequence the osmotic value of the vacuoles increases. The proton gradient is believed to drive the transport of maltose from the symbiont into the host. Another but light independent effect of the monensin treatment is the swelling of peripheral alveoles of the ciliates, likewise indicating that the alveolar membrane contains an active proton pump

Robustness of Randomized Rumour Spreading

In this work we consider three well-studied broadcast protocols: Push, Pull and Push&Pull. A key property of all these models, which is also an important reason for their popularity, is that they are presumed to be very robust, since they are simple, randomized, and, crucially, do not utilize explicitly the global structure of the underlying graph. While sporadic results exist, there has been no systematic theoretical treatment quantifying the robustness of these models. Here we investigate this question with respect to two orthogonal aspects: (adversarial) modifications of the underlying graph and message transmission failures. We explore in particular the following notion of Local Resilience: beginning with a graph, we investigate up to which fraction of the edges an adversary has to be allowed to delete at each vertex, so that the protocols need significantly more rounds to broadcast the information. Our main findings establish a separation among the three models. It turns out that Pull is robust with respect to all parameters that we consider. On the other hand, Push may slow down significantly, even if the adversary is allowed to modify the degrees of the vertices by an arbitrarily small positive fraction only. Finally, Push&Pull is robust when no message transmission failures are considered, otherwise it may be slowed down. On the technical side, we develop two novel methods for the analysis of randomized rumour spreading protocols. First, we exploit the notion of self-bounding functions to facilitate significantly the round-based analysis: we show that for any graph the variance of the growth of informed vertices is bounded by its expectation, so that concentration results follow immediately. Second, in order to control adversarial modifications of the graph we make use of a powerful tool from extremal graph theory, namely Szemer\`edi's Regularity Lemma.Comment: version 2: more thorough literature revie

Cultivo agrícola sob proteção total.

bitstream/item/58275/1/18-cultivo-Reisser-2011.pd

Genetic Basis of Ammonium Toxicity Resistance in a Sake Strain of Yeast: A Mendelian Case.

High concentrations of ammonium at physiological concentrations of potassium are toxic for the standard laboratory strain of Saccharomyces cerevisiae In the original description of this metabolic phenotype, we focused on the standard laboratory strains of Saccharomyces In this study, we screened a large collection of S. cerevisiae natural isolates and identified one strain that is resistant to high concentrations of ammonium. This strain, K12, was isolated in sake breweries. When the K12 strain was crossed to the standard laboratory strain (FY4), the resulting tetrads displayed 2:2 segregation of the resistance phenotype, suggesting a single gene trait. Using a bulk segregant analysis strategy, we mapped this trait to a 150-kb region on chromosome X containing the TRK1 gene. This gene encodes a transporter required for high-affinity potassium transport in S. cerevisiae Data from reciprocal hemizygosity experiments with TRK1 deletion strains in K12 and BY backgrounds, as well as analysis of the deletion of this gene in the K12 strain, demonstrate that the K12 allele of TRK1 is responsible for ammonium toxicity resistance. Furthermore, we determined the minimal amount of potassium required for both the K12 and laboratory strain needed for growth. These results demonstrate that the gene encoded by the K12 allele of TRK1 has a greater affinity for potassium than the standard allele of TRK1 found in Saccharomyces strains. We hypothesize that this greater-affinity allele of the potassium transporter reduces the flux of ammonium into the yeast cells under conditions of ammonium toxicity. These findings further refine our understanding of ammonium toxicity in yeast and provide an example of using natural variation to understand cellular processes

Construcao de estufa modelo capela.

bitstream/item/125147/1/Documentos-43.pd

Manejo da água em pomares de pessegueiro.

bitstream/item/30873/1/Circular-73.pd

Atlas climático da Região Sul do Brasil: Estados do Paraná, Santa Catarina e Rio Grande do Sul.

Este atlas é dividido em quatro principais seções, sendo a primeira a descrição conceitual e metodológica das variáveis meteorológicas. A segunda seção compreende uma análise, por meio de gráficos, das principais características climáticas dos mais diversos ambientes regionais. Em seguida, estão disponíveis, na forma de tabelas, os dados mensais, estacionais e anuais que podem ser usados para outros fins, conforme a necessidade do leitor. Por último, ele apresenta mais de duas centenas de mapas que revelam, de forma ilustrada e de fácil visualização, um conjunto de variáveis de temperatura, precipitação pluvial, classificações climáticas, entre outras informações.bitstream/item/143521/1/Atlas-climatico-da-regiao-Sul-do-Brasil.pdf2ª ediçã