How much variation in tree mortality is predicted by soil and topography in Central Amazonia?

Tree mortality in Amazonia has been related to regional variation in soil, topography and climatic disturbances, but the magnitude of the effect of these factors on tree mortality at local and mesoscales remains poorly determined. We investigated tree mortality in 72 1-ha permanent plots spanning 64 km² of tropical moist forest in Reserva Ducke, Manaus, Brazil. Plots were censused three times (2000-2003, 2003-2005, and 2005-2008), resulting in two census intervals. The relationships of soil and topography to tree mortality were dependent on tree size. Small- and medium-sized trees (1 ? dbh < 30 cm) had similar relationships of mortality with soil and topography, while large trees (dbh ? 30 cm) showed different (or no) relationships. The effects of soil and topography on tree mortality also varied temporally. In the second census interval after storms, soil and topography explained about one-fourth of the spatial variation in mortality of small- and medium-sized trees (<30 cm dbh), whereas no effects were detected in the first census interval. In particular, soil fertility was the most important predictor of tree mortality in the study area. Topography alone (altitude and slope) was associated with only 12% of the spatial variation in tree mortality and the magnitude of the effect of soil and topography on tree mortality also increased after storms. In general, plots on more fertile soils, on steep slopes and sandy soils in valleys showed greater tree mortality than those on plateau with well-drained clayey soils. Therefore, disturbance history and tree size should be included when scaling up tree mortality from local to regional scales. As much variation remains unexplained, other landscape features, such as watershed morphology and wind exposure, may be necessary to make more precise predictions on patterns of tree mortality in Central Amazonia.     

RAPD and ISSR molecular markers in <Emphasis Type="Italic">Olea europaea</Emphasis> L.: Genetic variability and molecular cultivar identification

Thirty Portuguese and eight foreign olive (Olea europaea L.) cultivars were screened using Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeat (ISSR) markers. Twenty RAPD primers amplified 301 reproducible bands of which 262 were polymorphic; and 17 ISSR primers amplified 204 bands of which 180 were polymorphic. The percentage of polymorphic bands detected by ISSR and RAPD was similar (88 and 87%, respectively). The genetic variability observed was similar in the Portuguese and foreign olive cultivars. Seven ISSR and 12 RAPD primers were able to distinguish individually all 38 olive cultivars. Twenty specific molecular markers are now available to be converted into Sequence Characterised Amplified Region (SCAR) markers. Relationships among Portuguese and foreign cultivars is discussed.     

Macronutrient accumulation in wheat crop (Triticum aestivum L.) with Azospirillum brasilense associated with nitrogen doses and sources

Abstract

New studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2?×?5?×?2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200?kg ha^?1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140?kg ha^?1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization.     

Heavy Metal Contamination in Sediments of Lake Nahuel Huapi,Nahuel Huapi National Park,Northern Patagonia,Argentina

Trace metals (Sb, As, Br, Cs, Co, Cr, Ag and Hg), rare earth elements (Ce, Eu, La, Lu, Sm, Tb and Yb), and Sc. were analysed in suspended load and in two sediment cores from Lake Nahuel Huapi, Nahuel Huapi National Park, Patagonia, Argentina, by using Instrumental Neutron Activation Analysis. The core activity profiles of ²¹⁰Pb and ¹³⁷Cs were measured to estimate the age of the sediments. Silver was enriched in the upper layers of both cores, and correlated with the strong growthof the population of Bariloche City in the last 50 yr. Concentrations are higher in the core sampled near Bariloche, andindicate some transport in the water body. Silver concentrationsmeasured in the suspended load were 4.58±0.36 and 3.46±0.40 μg g^-1 in the southern margin of the lake, near San Carlos de Bariloche City, whereas in the northern margin the concentrations were 1.68±0.18 and 1.88±0.23 μg g^-1. Concentration ratio for silver in suspended load and upper core layers were equal in both sampling points. These facts suggest that Ag contents correspond to inputs associated with human activities. Bromine concentrations show a strong increase abovebase line values, similar to silver. In contrast, caesium, chromium, and cobalt concentrations do not differ from base linevalues. The metalloids antimony and arsenic show little variationwith regard to base line concentration. Noticeable, the mercurycontents found in the suspended load.     

Improving the health of the global poor

We analyzed the technical basis for a major global program to reduce disease among the poor. Effective interventions exist against the few diseases which most account for excess mortality among the poor. Achieving high coverage of effective interventions requires a well-functioning health system, as well as overcoming a set of financial and nonfinancial constraints. The annual incremental cost would be between $40 billion and $52 billion by 2015 in 83 low-income and sub-Saharan African countries. Such a program is feasible and would avoid millions of child, maternal, and adult deaths annually in poor countries.     

Ecological effects of a major oil spill on panamanian coastal marine communities

In 1986 more than 8 million liters of crude oil spilled into a complex region of mangroves, seagrasses, and coral reefs just east of the Caribbean entrance to the Panama Canal. This was the largest recorded spill into coastal habitats in the tropical Americas. Many population of plants and animals in both oiled and unoiled sites had been studied previously, thereby providing an unprecedented measure of ecological variation before the spill. Documenation of the spread of oil and its biological begun immediately. Intertidal mangroves, algae, and associated invertebrates were covered by oil and died soon after. More surprisingly, there was also extensive mortality of shallow subtidal reef corals and infauna of seagrass beds. After 1.5 years only some organisms in areas exposed to the open sea have recovered.     

Spending money on others promotes happiness

Although much research has examined the effect of income on happiness, we suggest that how people spend their money may be at least as important as how much money they earn. Specifically, we hypothesized that spending money on other people may have a more positive impact on happiness than spending money on oneself. Providing converging evidence for this hypothesis, we found that spending more of one's income on others predicted greater happiness both cross-sectionally (in a nationally representative survey study) and longitudinally (in a field study of windfall spending). Finally, participants who were randomly assigned to spend money on others experienced greater happiness than those assigned to spend money on themselves.     

Comparative genomics of trypanosomatid parasitic protozoa

A comparison of gene content and genome architecture of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major, three related pathogens with different life cycles and disease pathology, revealed a conserved core proteome of about 6200 genes in large syntenic polycistronic gene clusters. Many species-specific genes, especially large surface antigen families, occur at nonsyntenic chromosome-internal and subtelomeric regions. Retroelements, structural RNAs, and gene family expansion are often associated with syntenic discontinuities that-along with gene divergence, acquisition and loss, and rearrangement within the syntenic regions-have shaped the genomes of each parasite. Contrary to recent reports, our analyses reveal no evidence that these species are descended from an ancestor that contained a photosynthetic endosymbiont.     

Deep Impact observations by OSIRIS onboard the Rosetta spacecraft

The OSIRIS cameras (optical, spectroscopic, and infrared remote imaging system) onboard the European Space Agency's Rosetta spacecraft observed comet 9P/Tempel 1 for 17 days continuously around the time of NASA's Deep Impact mission. The cyanide-to-water production ratio was slightly enhanced in the impact cloud, compared with that of normal comet activity. Dust particles were flowing outward in the coma at >160 meters per second, accelerated by the gas. The slope of the brightness increase showed a dip about 200 seconds after the impact. Dust Afrho values before and long after the impact confirm the slight decrease of cometary activity. The dust-to-water mass ratio was much larger than 1.     

Pericarp total protein profiles as molecular markers of tomato fruit quality traits in two segregating populations

The tomato fruit quality results of biochemical and physiological changes that occur during the ripening process. Although, the pericarp total protein profiles are less polymorphic than DNA-based markers the polymorphism in those could be directly associated with fruit quality traits. The aim of this work was to identify associations between polymorphic polypeptides from fruit pericarp at two ripening stages and fruit quality traits evaluated in two segregating populations of tomato. A cross between a normal ripening cultivar of Solanum lycopersicum (C, Caimanta) and a genotype carrying the nor (non ripening) gene (N) as well as a cross between Caimanta and a cherry type tomato of S. lycopersicum var. cerasiforme (Ce) showed genetic variance for several fruit quality traits such as fruit weight, shape, solids soluble content, acidity, color and fruit shelf life. The quantitative variations observed at phenotypic level had correspondence with the polymorphism detected in the protein profiles. Indeed, the polymophic polypeptides associated with quality fruit traits and fruit shelf life would be useful to assist tomato breeding programs as protein molecular markers.