ALBERT

Notes: Abstract The area studied is part of the “Ried Central” of the Ill river (Middle Alsatian plain in northeastern France). This area is located mainly in the present floodplain of the Ill. The closeness of the water table to the surface results in quasi general soil hydromorphism. The economic constraints of the last two decades led to deep changes in agricultural activities in the study area. These have essentially involved a marked extension of intensive cultivation of grain corn at the expense of grasslands. The study of the influence of this change on the parallel increase in the concentration of nitrate in groundwater is only feasible when a multidisciplinary approach is adopted. The analyses carried out in the field and in the laboratory show that nitrate reduction occurs in gleyed or peaty horizons of hydromorphic soils. The aptitude and efficiency of the permanent ambient vegetation (alluvial forests and grasslands) in retaining nitrate must be emphasized. The amount of nitrate eliminated from the aquifer by rivers fed by this aquifer is considerable. This evacuation of nitrate into the Ill is a fine example of waste and illustrates the absurdity of the economic situation responsible for excessive nitrogen fertilization of farmlands. In determining hazard zones, this study also proposes practical solutions to the problem of nitrate pollution: diminution of land area under cultivation, reintroduction of grasslands, and a more judicious use of nitrogen manure.

Notes: Summary The corneas of some nocturnal Lepidoptera carry an array of surface protuberances (nipples), about 200 mμ high, that acts as an impedance transformer equalizing by gradual transition the refractive index of air to that of the cornea. A screening of the insect class has been carried out in the present study with respect to the variation in corneal topography seen in previous obsarvations. 361 species in most insect orders were prepared for EM by thin sectioning or platinum replication. Using the amplitude of the surface protuberances as parameter, a grouping of the cornea types was made on the basis of the well-defined variation of nipple heights observed between individuals of certain species. Thus, the corneas of one extreme group were either smooth (Fig. 4A) or possessed protrusions (Fig. 4B and C) less than about 50 mμ high, arranged either irregularly or in a regular, hexagonal array (group I). At the other extreme, there was a group with “full-sized” nipples (Figs. 1 and 3) ranging in amplitude around 250 mμ (group III). An intermediate group of nipple heights (group II) comprised corneas with “low-sized” nipples (Fig. 6) between 50 and about 200 mμ high. Regularity in the arrangement of the various types of protuberances was observed both in groups I and II (compare Figs. 4C and 8). Irregularity tended to be associated with low amplitudes (e.g. Fig. 4B), being found only in group I corneas. Full-sized nipples (group III corneas) were found only among the anagenetically highest orders, Trichoptera and Lepidoptera (Tables 3 and 4), which, however, also had corneas with low protrusions (group I) and low-sized nipples (group II). In one of the two mecopteroid orders, Diptera (Table 2), protrusions and low-sized nipples were found (the latter only in Culicomorpha). The corneas of all other orders (Table 1) had only group I corneas with one noteworthy exception, Thysanura, the most primitive order investigated. All four thysanuran species examined had corneas with low-sized nipples (Fig. 8), thus belonging to group II. The morphological findings demonstrated in the present study can be taken to illustrate the following trends. 1.a)The higher relative number of group II and III corneas (low- and full-sized nipples) in the anagenetieally highest orders and the exclusive occurrence of group III corneas in the most advanced orders, Trichoptera and Lepidoptera, may indicate a progressive development of nipples during phylogenesis. Thus, the full-sized nipples may represent an apomorphous condition. Parallelisms — leading to the appearance of low- and full-sized nipples — may have occurred several times during insect phylogenetic development, thus possibly reflecting an evolutionary potential (with or without a selective pressure for this character). b)Low-sized nipples were found in the most primitive insect order, Thysanura. This circumstance may point to regression from full-sized nipples that were present in an ancestor common to all insects. In such a case, the full-sized nipples in Trichoptera and Lepidoptera are to be considered plesiomorphous. At present nothing supports conclusively a preference for one of these two alternatives. 2.Among the Lepidoptera, a greater relative number of butterflies than moths lack full-sized nipples. This may be taken to indicate a regression of nipples in the day-flying group of insects in comparison with their possible moth-like, nocturnal ancestors. That in many species there are low-sized nipples (the regression thus being incomplete) may indicate that a function of the nipples in ranges of shorter wavelengths has brought about an arrest of the regression at lower amplitudes.

Notes: Abstract We report transverse-field muon-spin-rotation experiments carried out on Tl2Ba2CuO6+δ . This system spans the whole overdoped regime, andT c is reduced by excess oxygen doping, which increases the normal-state carrier concentration. In the heavily overdoped regimeσ(0) is found to scale linearly with the superconducting critical temperatureT c , similar to the behavior previously observed for other cuprates in the underdoped regime. However, for the overdoped region one has to explain the reduction ofσ 0, thus the increase of the magnetic penetration depthλ, in spite of an increasing normal-state carrier concentration. We discuss some possible explanations for this behavior.

Notes: Abstract Matrices are manufactured by direct compression of a powder mixture of a polymer, e.g., methylhydroxypropyl cellulose (MHPC) or polyvinylalcohol (PVAI), and a drug. The following factors that can influence the drug release mode were investigated at constant surface: (i) polymer solution viscosity, glass transition temperature, and swelling; (ii) drug concentration in the matrix and solubility; and (iii) conditions of release experiment (hydrodynamics). In the case of zero-order release profiles (hydrocolloids with low viscosities), only the dissolution of the polymer appears to control the drug release rate. Factors accelerating polymer dissolution resulted in higher release rates. Comparison of swollen and dry hydrocolloid matrices shows that the duration and kinetics of drug release were not controlled by the swelling front moving into the dry polymer, and water penetration and relaxation were not rate controlling. Therefore, the glass transition temperature had no effect on drug release from these hydrocolloids. The higher the hydrodynamic stress exerted on the eroding hydrocolloid, the faster the resulting drug release as a result of accelerated polymer dissolution. With hydrocolloids of very high viscosity the polymer dissolution is slow, and drug relese from the swollen gel appears to be controlled by diffusion according to kinetics of the Higuchi type.