A connectome and analysis of the adult Drosophila central brain

The neural circuits responsible for animal behavior remain largely unknown. We summarize new methods and present the circuitry of a large fraction of the brain of the fruit fly Drosophila melanogaster. Improved methods include new procedures to prepare, image, align, segment, find synapses in, and proofread such large data sets. We define cell types, refine computational compartments, and provide an exhaustive atlas of cell examples and types, many of them novel. We provide detailed circuits consisting of neurons and their chemical synapses for most of the central brain. We make the data public and simplify access, reducing the effort needed to answer circuit questions, and provide procedures linking the neurons defined by our analysis with genetic reagents. Biologically, we examine distributions of connection strengths, neural motifs on different scales, electrical consequences of compartmentalization, and evidence that maximizing packing density is an important criterion in the evolution of the fly’s brain

A connectome and analysis of the adult Drosophila central brain

The neural circuits responsible for animal behavior remain largely unknown. We summarize new methods and present the circuitry of a large fraction of the brain of the fruit fly Drosophila melanogaster. Improved methods include new procedures to prepare, image, align, segment, find synapses in, and proofread such large data sets. We define cell types, refine computational compartments, and provide an exhaustive atlas of cell examples and types, many of them novel. We provide detailed circuits consisting of neurons and their chemical synapses for most of the central brain. We make the data public and simplify access, reducing the effort needed to answer circuit questions, and provide procedures linking the neurons defined by our analysis with genetic reagents. Biologically, we examine distributions of connection strengths, neural motifs on different scales, electrical consequences of compartmentalization, and evidence that maximizing packing density is an important criterion in the evolution of the fly's brain

Effects of air filtration at small SO2 and NO2 concentrations on the yield of barley.

Two cultivars of Igri and Gerbel winter barley Horteum vulgare L. were grown in open-top chambers in filtered and unfiltered air at a site with approximately 10 nl litree−1 SO2 and 12 nl litre−1 NO2 (seasonal mean). The experiment ran for three consecutive seasons 1982–1983, 1983–1984, 1984–1985, and significant effects of filtration were observed for each crop. In years 1982–1983 and 1984–1985, the crops in unfiltered air yielded larger grain dry matter, 9% in 1982–1983, and 8% in 1984–1985. For both crops, the differences were statistically significant at the 5% level. Differences were also observed for the remaining above-ground dry matter, and these were consistent in direction in each year but statistically significant only in 1984–1985. In both growing seasons (1982–1983 and 1984–1985), there were no major pest infestations and no long-term water stress or photochemical ozone episodes. In the remaining experiment (1983–1984) similar air concentrations of SO2 and NO2 produced effects of the opposite sign to those observed in 1982–1983 and 1984–1985. Significant reductions in grain yield (13%) were obtained in unfiltered air. The only major environmental difference for the 1983–1984 crop was a notable dry period in May and June 1984 with marked water stress in the crop, requiring irrigation. These results suggest that the relationship between yield and pollutant concentration may be confounded by additional stresses, many of which are a common component of the growing season for major crops

Chemical composition of rainfall and wet deposition over northern Britain.

Results are presented for the chemical composition of precipitation sampled monthly at 16 sites in northern Britain for 1981. Distribution maps of concentration of H+, NO3− and non-marine SO42− show gradients increasing from the north-west to the south and east (H+ from 10 to 40 μeq ℓ−1, NO3− from 10 to 30 μeq ol−1, non-marine SO42− from 15 to 60 μeq ℓ−1) but the distribution of NH4+ was not simple. Deposition of all ions was greatest in the mountainous areas of the south and west, where rainfall amounts were largest. Concentrations of NH4+ and NO3− were approximately the same in 1980and 1981, but H+ and non-marine SO42− concentrations were significantly smaller in 1981 than in 1980. Longer term trends (1978–1982) were site-dependent, with large variability between years. Acidity decreased at all sites over this period, but no conclusions can be drawn on the causes of the observed decrease. Seasonal variations in 1981 were also strongly site-dependent; pronounced annual cycles in concentration were observed at southeastern sites for H+, NH4+, NO3− and non-marine SO42−, with maxima in late spring. Sea-derived material (Na+ and Cl−) showed pronounced cycles in concentration at all sites, with maxima in autumn/winter, annual cycles in deposition depending upon the annual cycle in precipitation amount. Deposition of H+, NH4+, NO3− and non-marine SO42− was greatest in the autumn at northwest sites and in the spring at southeast sites