On the relative abundance of autopolyploids and allopolyploids.

The prevalence of autopolyploids in angiosperms has long been a subject of debate. Meurountzing (1936) and Darlington (1937) conclude d that autopolyploids were common and important evolutionary entities. However, Clausen et al. (1945) and Stebbins (1947) subsequently considered them rare, in part because the criteria upon which interpretations of autopolyploidy were rendered were not rigorous. This position was reiterated by Grant (1981) decades later, although evidence was mounting that autopolyploid taxa might be important in natural populations (Lewis, 1980). As cytological and genetic data have accumulated, it has become increasingly apparent that the latter view is likely to be correct (Soltis et al., 2004b, 2007, 2010). However, it still appears that the majority of polyploids are allopolyploids (Parisod et al., 2010; Soltis et al., 2010), even though Ramsey & Schemske (1998, p. 467) conclude that 'the rate of autopolyploid formation may often be higher than the rate of allopol yploid formation.' In this letter we survey the literature to assess whether allopolyploids are indeed the prevailing cytotype in nature. Using our new estimates for the incidence of autopolyploidy and allopolyploidy, we discuss some of the evolutionary dynamics that may be driving their frequencies in nature. Finally, we suggest avenues for future research on polyploidy that build on our results and other recent progress in the field.

Approximate solution to the speed of spreading viruses

Recently, it has been shown that the speed of virus infections can be explained by time-delayed reactiondiffusion [J. Fort and V. Me´ndez, Phys. Rev. Lett. 89, 178101 (2002)], but no analytical solutions were found. Here we derive formulas for the front speed, valid in appropriate limits. We also integrate numerically the evolution equations of the system. There is good agreement with both numerical and experimental speeds

Indirect likelihood inference (revised)

Standard indirect Inference (II) estimators take a given finite-dimensional statistic, Z_{n} , and then estimate the parameters by matching the sample statistic with the model-implied population moment. We here propose a novel estimation method that utilizes all available information contained in the distribution of Z_{n} , not just its first moment. This is done by computing the likelihood of Z_{n}, and then estimating the parameters by either maximizing the likelihood or computing the posterior mean for a given prior of the parameters. These are referred to as the maximum indirect likelihood (MIL) and Bayesian Indirect Likelihood (BIL) estimators, respectively. We show that the IL estimators are first-order equivalent to the corresponding moment-based II estimator that employs the optimal weighting matrix. However, due to higher-order features of Z_{n} , the IL estimators are higher order efficient relative to the standard II estimator. The likelihood of Z_{n} will in general be unknown and so simulated versions of IL estimators are developed. Monte Carlo results for a structural auction model and a DSGE model show that the proposed estimators indeed have attractive finite sample properties.

Bifurcation of relative equilibria of the (1+3)-body problem

We study the relative equilibria of the limit case of the pla- nar Newtonian 4{body problem when three masses tend to zero, the so-called (1 + 3){body problem. Depending on the values of the in- nitesimal masses the number of relative equilibria varies from ten to fourteen. Always six of these relative equilibria are convex and the oth- ers are concave. Each convex relative equilibrium of the (1 + 3){body problem can be continued to a unique family of relative equilibria of the general 4{body problem when three of the masses are su ciently small and every convex relative equilibrium for these masses belongs to one of these six families.

Influence of basic properties of Mg,Al-mixed oxides on their catalytic activity in knoevenagel condensation between benzaldehyde and phenylsulfonylacetonitrile

The catalytic performance of Mg,Al-mixed oxides (MO20, MO25 and MO33) derived from hydrotalcites was evaluated in the Knoevenagel reaction between benzaldehyde and phenylsulfonylacetonitrile at 373 and 383 K. The best results were obtained for the sample MO20 that presented the highest basic sites density and external area and the smallest crystallite sizes. The relative amount of basic sites with weak to intermediate strength also played an important role on catalytic performance. By increasing the catalyst content from 1 to 5 wt.% at 383 K, a complete conversion of the reactants is attained, producing α-phenylsulfonylcinnamonitrile with a selectivity of 100%.

Validação de método e determinação espectrométrica dos flavonoides das folhas e do vinhoto da cana-de-açúcar e comparação com método CLAE-UV

This paper reports on a modification of the procedures originally described in the French Pharmacopoeia for the UV-visible spectrometric analysis of flavonoids, and proposes a validation of the method and its application in the determination of total flavonoids from sugarcane (Saccharum officinarum) leaves and vinasse. An analysis of precision and accuracy revealed a low relative standard deviation (< 5.0%) and a good recovery percentages (99.79 and 98.34%). A comparison of the spectrometric results against those obtained by high performance liquid chromatography (HPLC-UV) demonstrated complete compatibility between the modified French Pharmacopoeia (spectrometric) and HPLC-UV methods

BIOSSENSOR ELETROQUÍMICO BASEADO NA ENZIMA TIROSINASE PARA A DETERMINAÇÃO DE FENOL EM EFLUENTES

AbstractThis work describes the development of a biosensor based on the tyrosinase enzyme (Tyr) for the determination of phenol (PHEN) in laboratory effluent samples derived from ammoniacal nitrogen analysis of the water samples from the Muquém dam in the city of Cariús, CE, using square-wave voltammetry (SWV). The electrode modification consisted of the immobilization of gold nanoparticles, multi-walled carbon nanotubes, cobalt phthalocyanine, and Tyr on a glassy carbon electrode. The electrolyte, pH, enzyme quantity, and voltammetric parameters were optimized to detect PHEN. The analytical curves presented a linear range from 4.97 × 10-6 mol L-1 to 6.10 × 10-5 mol L-1, and the detection limit (DL) and quantitation limit (QL) values were 4.81 × 10-6 mol L-1 and 4.97 × 10-6mol L-1, respectively. The repetition of measurements with the same biosensor and repetition for three other prepared biosensors exhibited a relative standard deviation (RSD) of 5.50 and 1.75%, respectively. The percentage recovery of PHEN in effluent samples varied from 86.40 to 105.04%. The stability of the biosensor was evaluated (at 21 days) with satisfactory results, showing 97.86% of the initial response. Moreover, the DL and recovery percentages agreed with the established values from CONAMA and ABNT, respectively. Thus, the electrode configuration developed seems a promising tool in the detection and quantification of PHEN in complex samples.

A SECOND OPINION ON RELATIVE TRUTH

In 'An undermining diagnosis of relativism about truth', Horwich claims that the notion of relative truth is either explanatorily sterile or explanatorily superfluous. In the present paper, I argue that Horwich's explanatory demands set the bar unwarrantedly high: given the philosophical import of the theorems of a truth-theoretic semantic theory, Horwich's proposed explananda, what he calls acceptance facts, are too indirect for us to expect a complete explanation of them in terms of the deliverances of a theory of meaning based on the notion of relative truth. And, to the extent that there might be such an explanation in certain cases, there is no reason to expect relative truth to play an essential, ineliminable role, nor to endorse the claim that it should play such a role in order to be a theoretically useful notion.

Relative reduction in annual soil loss in micro watersheds due to the relief and forest cover

With the intense debate, in Brazil, between landowners and public agencies about the amount of area with forest cover needed in different regions, there is an increase of the need for provision of technical data used as a basis for decision making. One of the criteria to evaluate the effect of forest cover in protecting water resources is the soil loss, which leads to several consequences on the environment, including the silting of the rivers. Therefore, this study aimed to evaluate the reduction in the soil loss in micro watersheds with different reliefs, size and location of forest cover, in the Corumbataí River watershed, in the state of São Paulo, using the Revised Universal Soil Loss Equation (RUSLE) in a GIS environment. For this study, 18 watersheds in three degrees of slope were selected, and 20 scenarios for land-use were established, by analyzing the influence of the PPA size, and the size and the location of the Legal Reserve. The results showed that: a) the effect of forest cover in reducing annual soil loss varies depending on the average slope of the watershed; b) the PPA width must be determined taking into account the slope of the watershed; c) the Legal Reserve must be located along the PPA. These provide better results in reducing annual soil loss.

Corrosion behaviour of boiler tube materials during combustion of fuels containing Zn and Pb

Många förbränningsanläggningar som bränner utmanande bränslen såsom restfraktioner och avfall råkar ut för problem med ökad korrosion på överhettare och/eller vattenväggar pga. komponenter i bränslena som är korrosiva. För att minimera problemen i avfallseldade pannor hålls ångparametrarna på en relativt låg nivå, vilket drastiskt minskar energiproduktionen. Beläggningarna i avfallseldade pannor består till största delen av element som är förknippade med högtemperaturkorrosion: Cl, S, alkalimetaller, främst K och Na, och tungmetaller som Pb och Zn, och det finns också indikationer av Br-förekomst. Det låga ångtrycket i avfallseldade pannor påverkar också stålrörens temperatur i pannväggarna i eldstaden. I dagens läge hålls temperaturen normalt vid 300-400 °C. Alkalikloridorsakad (KCl, NaCl) högtemperaturkorrosion har inte rapporterats vara relevant vid såpass låga temperaturer, men närvaro av Zn- och Pb-komponenter i beläggningarna har påvisats förorsaka ökad korrosion redan vid 300-400 °C. Vid förbränning kan Zn och Pb reagera med S och Cl och bilda klorider och sulfater i rökgaserna. Dessa tungmetallföreningar är speciellt problematiska pga. de bildar lågsmältande saltblandningar. Dessa lågsmältande gasformiga eller fasta föreningar följer rökgasen och kan sedan fastna eller kondensera på kallare ytor på pannväggar eller överhettare för att sedan bilda aggressiva beläggningar. Tungmetallrika (Pb, Zn) klorider och sulfater ökar risken för korrosion, och effekten förstärks ytterligare vid närvaro av smälta. Motivet med den här studien var att få en bättre insikt i högtemperaturkorrosion förorsakad av Zn och Pb, samt att undersöka och prediktera beteendet och motståndskraften hos några stålkvaliteter som används i överhettare och pannväggar i tungmetallrika förhållanden och höga materialtemperaturer. Omfattande laboratorie-, småskale- och fullskaletest utfördes. Resultaten kan direkt utnyttjas i praktiska applikationer, t.ex. vid materialval, eller vid utveckling av korrosionsmotverkande verktyg för att hitta initierande faktorer och förstå deras effekt på högtemperaturkorrosion.

Comparison of Classical and Secondary Cytologic Criteria Relative to Hybrid Capture for Diagnosing Cervical-vaginal Infection by Human Papillomavirus

Objective To compare the diagnostic accuracy of the classic Meisels cytologic criteria and the Schneider secondary criteria relative to the hybrid capture method for diagnosing HPV infection. Methods This was a retrospective study performed at a public university hospital. A total of 41 patients with a cytologic diagnosis of HPV infection and 40 HPV-negative patients were selected for review of the cervical-vaginal smears seeking to classical and secondary criteria. A single pathologist reviewed the slides in search of the criteria. The classical and secondary cytologic criteria were compared with the hybrid capture for diagnosing HPV infection. Bartleti test was applied for the age analysis, and Fisher's exact test was used to compare proportions. The tests were considered significant when the probability of rejecting the null hypothesis was less than 5% (p < 0.05). Results The Meisels criteria were less sensitive (34.0%) than the secondary Schneider criteria (57.5%) when compared with the hybrid capture (p < 0.0001), although the specificity of the former criteria was non-significantly higher (91.2% and 67.7%, respectively). In cases of moderate or intense inflammation, the sensitivity and specificity of the Schneider criteria were decreased, 33.3% and 50.0% respectively (p = 0.0115). Conclusions Compared with hybrid capture for diagnosis of HPV infection, the sensitivity of the secondary Schneider criteria was higher than the classical Meisels criteria.Moderate or intense inflammation reduces the sensitivity and specificity of the secondary Schneider criteria for diagnosing HPV infection using the hybrid capture as the gold standard.

Characterization of Leaf-Type Ferredoxin-NADP+ Oxidoreductase (FNR) Isoforms in Arabidopsis thaliana

Life on earth is based on sunlight, which is captured in chemical form by photosynthetic reactions. In the chloroplasts of plants, light reactions of photosynthesis take place at thylakoid membranes, whereas carbon assimilation reactions occur in the soluble stroma. The products of linear electron transfer (LET), highly-energetic ATP molecules, and reducing power in the form of NADPH molecules, are further used in the fixation of inorganic CO2 molecules into organic sugars. Ferredoxin-NADP+ oxidoreductase (FNR) catalyzes the last of the light reactions by transferring electrons from ferredoxin (FD) to NADP+. In addition to LET, FNR has been suggested to play a role in cyclic electron transfer (CET), which produces ATP without the accumulation of reducing equivalents. CET is proposed to occur via two putative routes, the PGR5- route and the NDH-route. In this thesis, the leaf-type FNR (LFNR) isoforms LFNR1 and LFNR2 of a model organism, Arabidopsis thaliana, were characterized. The physiological roles of LFNRs were investigated using single and double mutant plants. The viability of the single mutants indicates functionality of both isoforms, with neither appearing to play a specific role in CET. The more severe phenotype of low-temperature adapted fnr2 plants compared to both wild-type (WT) and fnr1 plants suggests a specific role for LFNR2 under unfavorable growth conditions. The more severe phenotype of the fnr1 x fnr2 (F1 generation) plants compared to single mutants reflects down-regulated photosynthetic capacity, whereas slightly higher excitation pressure indicates mild over-excitation of electron transfer chain (ETC). However, induction of CET and various photoprotective mechanisms enable adaptation of fnr1 x fnr2 plants to scarcity of LFNR. The fnr1 fnr2 plants (F2 generation), without detectable levels of LFNR, were viable only under heterotrophic conditions. Moreover, drought stress induced acceleration of the rate of P700 + re-reduction in darkness was accompanied by a concomitant up-regulation of the PGR5-route specific components, PGR5 and PGRL1, demonstrating the induction of CET via the PGR5-route. The up-regulation of relative transcriptional expression of the FD1 gene indicates that the FD1 isoform may have a specific function in CET, while no such role could be defined for either of the LFNR isoforms. Both the membrane-bound and soluble LFNR1 and LFNR2 each appear as two distinct spots after 2D-PAGE with different isoelectric points (pIs), indicating the existence of post-translational modifications (PTMs) which do not determine the membrane attachment of LFNR. The possibility of phosphorylation and glycosylation PTMs were excluded, but all four LFNR forms were shown to contain acetylated lysine residues as well as alternative N-termini. N-terminal acetylation was shown to shift the pI of both LFNRs to be more acidic. In addition, all four LFNR forms were demonstrated to interact both with FD1 and FD2 in vitro

Leaf damage in a mangrove swamp at Sepetiba Bay, Rio de Janeiro, Brazil

Leaf damage to Rhizophora mangle L., Avicennia schaueriana Stapf. & Leechman, and Laguncularia racemosa L. was studied in a two hectare mangrove swamp site in Sepetiba Bay. Seventeen arthropod morphospecies were identified as being responsible for the damage, and their species diversity was highest on A. schaueriana, followed by R. mangle and L. racemosa. Damage in terms of relative area was greatest in L. racemosa. Almost 9% of mangrove canopy leaf area demonstrated some damage. Loss of leaf area to herbivory was 12.1%, 8.3% and 6.2% in L. racemosa, A. schaueriana and R. mangle respectively. L. racemosa and A. schaueriana showed high percentages of leaf-margin damage in terms of the total damaged leaf area (82.2% and 56.3% respectively), while the most important type of damage in R. mangle was necrosis, representing 58.1% of the total damaged leaf area.

Overcoming crossing barriers between cassava, Manihot esculenta Crantz and a wild relative, M. pohlii Warwa

The use of mentor pollen has enabled successful hybridization between cassava, Manihot esculenta Crantz, and the wild species M. pohlii Warwa. Killed pollen of a cross compatible type produced by freeze-thawing was mixed with incompatible pollen and the mixes were dusted on stigmas. This treatment resulted in production of seed in 4.9% of the total pollinations, compared to 0% in the case of untreated pollinations. The use of a bridge species, M. neusana Nassar, through the hybrid M. pohlii and M. neusana also proved successful in overcoming interspecific barriers between cassava and M. pohlii.