Uncovering organizational principles of the cerebral cortex is essential for proper understanding of this prominent structure of the mammalian brain. The theory of the dual origin of the cerebral cortex offers such organizational principle. Here, we demonstrate that a duality pertains to the connectional architecture of the cerebral cortex of different mammals. This dual structure also constitutes a major axis of organization of the transcriptional architecture of the cortex and reflects the expression of different morphogens stemming from distinct patterning centers in the developing pallium. The duality of the cortex is also reflected in its spatial dimension, highlighting cortical areas as spatially ordered constellations that are centered around the paleocortex and archicortex, with the later primordial moieties reminiscent of antipodal points in the cortical sheet. The ontogeny of the uncovered dual connectional structure might be rooted in heterochronous neurodevelopmental gradients in the developing pallium, a suggestion corroborated by computational modeling. In all, the current results exemplify the duality of the cerebral cortex as an overarching organizational principle, reflected across the different levels of cortical architecture of different mammalian species, defining a natural axis of mammalian cortical organization.

There is evidence that the brains of men and women are structurally different, but there are few data regarding possible sex differences in white matter microstructure. Using diffusion tensor imaging we assessed fractional anisotropy (FA) in the frontal lobe white matter on contiguous 5 mm slices in nine healthy male and 11 healthy female adults. Overall, women had higher FA in the left frontal lobe compared to men and a leftward asymmetry of FA in contrast to men, who showed no hemispheric asymmetry. Among women, greater leftward asymmetry of frontal lobe FA correlated significantly with better verbal comprehension and memory functioning. Our findings may be indicative of increased directional coherence and/or density of left hemisphere white matter fibers and a leftward asymmetry of this structural integrity among women compared to men.

A novel in situ device for the direct potentiometric detection of pH, pe and pH 2 S values (where p = −log activity) is introduced. The mechanical and electrochemical problems associated with liquid-junction type reference cells for pH and pe measurements are avoided by using an alkali glass electrode as a reference. The probe displayed stable EMF readings irrespective of hydrostatical pressure, temperature gradients and the presence of hydrogen sulphide when it was deployed in Lake Kinneret, Israel.

Stromatolites occurring in three areas of landlocked pools on Aldabra show distinctive morphologies, petrography and biological characteristics related both to water chemistry and the physical characteristics of sites. They are formed apparently by indirect precipitation of high-magnesium calcite in association with growths of cyanobacteria and Cladophora. The three contrasted areas are dominated respectively by Phormidium, Lyngbya and Pleurocapsa, by Entophysalis, Lyngbya and Pleurocapsa, and by Pleurocapsa, Dichothrix gypsophila and Schizothrix, reflecting an increasing concentration and increasing dissolved carbonate activity of pool waters. Centimeters to decimeters of carbonate encrustations are made up of irregular laminate columns, porous layered coatings of planar or cerebroid form (including oncolites) and finely laminate branching columns. Laminae are typically alternations of dense and porous micrite with, in one locality, radiating fibrous sparry crystal growths.

A feedback control system was applied to establish defined redox conditions in sediment-water systems: the H2S release was counterbalanced by adding of air oxygen on arbitrarily chosen pH2S setpoints. pH2S was measured by a pH2S electrode cell as the controlled variable. E. coli and Enterococci were inoculated into the system to study their survival. Applying a new kinetic approach different growth patterns were revealed, indicating that E. coli, in contrast to Enterococci, shows significant dependence on the predominating redox conditions. Enterococci may thus be a more reliable indicator of fecal contamination in cases were sulfide is present.

pH measurements on leaves of Hedera helix L. indicated the amount and strength of acids present on the leaves and the buffering mechanisms taking place. To measure the amount and strength of acids on dry leaves the leaf surfaces had to be wetted with water and the pH determined from at least two different wetting thicknesses. For strong acids ΔpH/Δlg vol should be + 0.95.

pH2S values (–log [H2S]) were calculated from the electrochemical reaction of a glass|Ag0, Ag2S electrode cell in equilibrium with metal sulphide precipitates at pH ⩽ 5 and compared with pH2S values predicted by the law of mass action. The results obtained indicated that the pH2S electrode cell has a Nernstian response at very low total sulphide concentrations. Measurements of the ion activity products in these solutions verified literature values. However, they also indicated that sulphide solubilities are influenced by the adsorption of hydrolysed metal species, leading to deviations from the theoretically predicted solubilities. As a general result, a detection limit for total sulphide activities corresponding to pH2S 18.2 was obtained. The electrode cell proved to be a suitable tool for the determination of the ion activity products of metal sulphides in difficult media (marine or estuarine waters) with a precision of ±0.3 logarithmic unit.

26 hydrochemical variables have been determined in 21 semitidal or non-tidal freshwater pits on Tarawa Atoll (Gilbet Islands, Central Pacific); the pits are used for the cultivation of Giant Taro (Cryptosperma chamissonis fa. Araceae) by the islanders who eat the plant's rhizom. In order to find master variables for the “fertility state” of the pits, the data were evaluated statistically including autocorrelation test, principal component analysis and discriminant analysis. As a result no autocorrelation was found, and pH and pH2S (≡ -lg [H2S]) in the pit's upper lying sludges turned out to be most discriminatory (mean F-value 4.63 with 0.2% error and 98.3% variance of the 1. eigenvalue). Due to a corresponding prediction model the differentiation between “well cultivation conditions” and “bad cultivation conditions” is possible by detecting pH and pH2S in the sediment of the pit.

The beginning of the bloom of Chlorobium phaeobacteroides in Lake Kinneret is accompanied by the occurrence of cells of Thiocapsa roseopersicina, which subsequently disappear. It was found that Thiocapsa requires relatively high light intensities (50–100 μE∙m−2∙s−1) for growth which proved to be higher than that for Chlorobium. Acetate played an important role in the growth of Thiocapsa only when the organisms were exposed to light intensities which were not optimal for photosynthesis. Optimum total sulfide concentrations for growth of Thiocapsa were found to be in the range of 1–3 mM. Considering the differential uptake of the reduced sulfur components H2S and HS−, a preference for HS− is suggested. It seems further likely that H2S inhibits growth at concentrations above 1 mM, independent of the pH. Compared with Chlorobium, favourable conditions for Thiocapsa at the beginning of the bloom period are due to low in situ concentrations of H2S, which prevent rapid development of Chlorobium.

Nebel- und Regenwasserproben aus dem Frankenwald nahe Bad Steben (N-Bayern) wurden wöchentlich gesammelt und milde eingedampft. Dabei wurde die Änderung des pH-Wertes gemessen. Regenwasserproben mit anfänglichen pH-Werten um 4,3 zeigten pH-Wert-Erniedrigungen, die aufgrund entsprechender theoretischer Gberlegungen bezüglich des Einflusses von Säurestärken und Volumeneinengung zu erwarten waren. Geringfügige Abweichungen hiervon wurden im Nebelwasser bei pH < 4 gefunden. Eine Regenwasserprobe mit anfänglich pH = 5,7 änderte ihren Wert nur um −0,2 Einheiten, was eine Säureanhydridentgasung (CO2) vermuten läßt.

On observe une plus forte concentration en polluants dans les eaux de brouillard que dans les eaux de pluie