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Thin films of bismuth vanadate (BiVO) are deposited through the solution combustion synthesis technique coupled with the dip-coating process. Thermal gravimetric analyis shows a total mass loss of 71 % besides the formation of the monoclinic phase, about 300 °C, which is also revealed by X-ray diffraction. UV-Vis optical absorption spectra show direct bandgap transition about 2.5 eV for films, in good agreement with semiconducting monoclinic phase. Scanning electron microscopic images reveal that thermal annealing time at 500 °C is a very important parameter to control the thickness and shape of the particles and yields an average thickness of about 800 nm for 10 dip-coated deposited layers, with round-shaped nanometric-sized particles, homogeneously distributed on the film surface. Photoelectrochemical degradation of methylene blue by a bismuth vanadate film deposited on fluor-doped tin oxide substrate shows up as a very efficient process. The first-order rate constant for the photoinduced process is about five times the rate constant for degradation in the dark, showing the capacity of the BiVO/fluorine-doped tin oxide film for electrochemical degradation, mainly in the presence of light. [ABSTRACT FROM AUTHOR]

In mobile animals, movement behavior can maximize fitness by optimizing access to critical resources and minimizing risk of predation. We sought to evaluate several hypotheses regarding the effects of landscape structure on American marten foraging path selection in a landscape experiencing forest perforation by patchcut logging. We hypothesized that in the uncut pre-treatment landscape marten would choose foraging paths to maximize access to cover types that support the highest density of prey. In contrast, in the post-treatment landscapes we hypothesized marten would choose paths primarily to avoid crossing openings, and that this would limit their ability to optimally select paths to maximize foraging success. Our limiting factor analysis shows that different resistant models may be supported under changing landscape conditions due to threshold effects, even when a species' response to landscape variables is constant. Our results support previous work showing forest harvest strongly affects marten movement behavior. The most important result of our study, however, is that the influence of these features changes dramatically depending on the degree to which timber harvest limits available movement paths. Marten choose foraging paths in uncut landscapes to maximize time spent in cover types providing the highest density of prey species. In contrast, following landscape perforation by patchcuts, marten strongly select paths to avoid crossing unforested areas. This strong response to patch cutting reduces their ability to optimize foraging paths to vegetation type. Marten likely avoid non-forested areas in fragmented landscapes to reduce risk of predation and to benefit thermoregulation in winter, but in doing so they may suffer a secondary cost of decreased foraging efficiency. [ABSTRACT FROM AUTHOR]

The weekly increments under various conditions of a dozen of 30 to 60 years old Halep pines grown in the Lecce area have been measured during two years with a band dendrometer. The data have been compared with the X-ray density of a stem in radial direction, the weekly precipitations and the integrated temperature excess above 8°C. We have found that growth rate behaviour is practically the same for all the pines considered. This indicate a strict dependence of growth on external factors such as climate and other environmental conditions. Vegetation activity does not seem to have regular dormancy periods: it stops when temperature and humidity become prohibitive and resumes as soon as they become favourable. The volume of wood formed in late-season (July-January) equals more or less that of early-season (February-June), whereas the wood mass and the number of cells in late-season is nearly double of that in early-season. During periods of high cambial activity one observes a lower cell lignification. However, on the whole, the photoperiodicity hypothesis in lignification seems to be confirmed. The growth rate appears inversely related to density. The lignification process appears to extend to the outer xylem layer of 1-2 mm and seems most effective during dry and warm seasons when cambial activity is low. Density wriggles appear to derive from combined variations of cambial activity, cell size and lignification, mostly corresponding to environmental events such as periods of drought or of cold weather. Finally, during the dry seasons we find that a precipitation event is generally followed within a time less than a week, by an increase of growth rate. Whereas during the wet season the growth rate variation is very similar to that of temperature excess. [ABSTRACT FROM AUTHOR]

Studies on chromosome numbers and karyotypes in Orchid taxa from Apulia (Italy) revealed triploid complements in Ophrys tenthredinifera and Orchis italica. In O. tenthredinifera there is no significant difference between the diploid and the triploid karyotypes. The tetraploid cytotype of Anacamptis pyramidalis forms 36 bivalents during metaphase I in embryo sac mother cells. Aneuploidy was noticed in Ophrys bertolonii × O. tarentina with chromosome numbers n = 19 and 2n = 38. There were diploid (2n = 2x = 36), tetraploid (2n = 4x = 72), hexaploid (2n = 6x = 108) and octoploid (2n = 8x = 144) cells in the ovary wall of the diploid hybrid Ophrys apulica × O. bombyliflora. Evolutionary trends in Ophrys and Orchis chromosomes are discussed. [ABSTRACT FROM AUTHOR]

We have analysed ring width sequences of 1.3 My old fossil trees, grown with no water deficit, in Dunarobba forest (Italy). We find evidence for a modulation period of the annual ring growth widths on time scale of 11 y to 15 y. Since similar modulation cycles have also been found by other authors in polar iceBe concentration of the last millennium and in a series of annual ring widths of a same kind of trees grown in Central Europe of 15-20 My ago, we suggest that such cycles might be related to solar-activity cycles. This would support the hypothesis of a quasi-periodic behaviour of the solar dynamical system controlled by an oscillator whose fundamental period is of 22-25y, that can be identified with the Hale cycle; this system would be operational at least since the Miocene era. [ABSTRACT FROM AUTHOR]