Home About us Contact
|
Home About us Contact | ||
|
|
||
Second Growth (second + growth)
Selected AbstractsIsland biogeography and landscape ecology of mammals inhabiting fragmented, temperate rain forestsGLOBAL ECOLOGY, Issue 2 2001Mark V. Lomolino Abstract 1We expanded the island biogeography paradigm to test whether mammalian communities of the heavily fragmented temperate rain forests of the Olympic Peninsula were influenced by local environmental conditions, biogeographic factors (fragment area and isolation) and characteristics of the surrounding landscape. 2We used live-trapping, sign surveys and infra-red triggered cameras to compare distributions of non-volant mammals among fragments and between fragments and other principal landscape components (continuous old-growth, riparian corridors, second-growth forest and clearcuts). 3Of the 24 species of non-volant mammals detected during our studies, 18 occurred in at least one fragment. 4Species richness of old-growth mammals was not significantly correlated with fragment area or isolation, per se, but was significantly and positively correlated with the amount of old-growth fragments and old second-growth (41,159 years) in the surrounding landscape (r2 = 0.95, P < 0.005). 5Distributions of three old-growth dependent species [shrew-mole (Neurotrichus gibbsii), Douglas squirrel (Tamiasciurus douglasii) and Trowbridge shew (Sorex trowbridgii)] were significantly associated with local environmental conditions within the fragment, with geographical isolation from continuous old-growth and riparian corridors, and with the amount of old-growth and old second growth in the adjacent matrix. [source] The effect of additives in silages of pure timothy and timothy mixed with red clover on chemical composition and in vitro rumen fermentation characteristicsGRASS & FORAGE SCIENCE, Issue 3 2003M. Hetta Abstract The aim was to compare the effects of additives on direct cut silages of pure timothy and timothy mixed with tetraploid red clover. First and second growth cuts were ensiled during three consecutive years, 1994, 1995 and 1996, either without any additive or with the addition of formic acid, or lactic acid bacteria in combination with molasses. Effects of the additives on the degradation characteristics of the herbage and the silages were analysed using an automatic in vitro gas production (GP) technique. At the end of the in vitro procedures, organic matter and neutral-detergent fibre (NDF) degradabilities were determined. The tetraploid red clover persisted in the leys during the 3 years and was the dominant species at the second growth in the mixed leys. The herbage from the mixed crops had lower dry-matter contents, higher crude protein concentrations and higher buffering capacity compared with the pure timothy at both cuts. In general, the additives reduced pH, and the concentrations of ammonium-N and acetic acid in the silages. The treated silages had a more rapid faster GP in both crops. The silages from the mixed crop benefited more from the additives compared with the grass silages. The additives affected the soluble fractions as well as the NDF degradability of the silages of the mixed crop more than those fractions of the grass silages. The addition of molasses in combination with a commercial inocula resulted in increased production of lactic acid and ethanol in silages from both crops. The silages without additives could not meet the requirements for good silages according to the standards of the Swedish dairy industry. [source] Epoxidation of allyl chloride and hydrogen peroxide over titanium silicalite-1 film on SiO2 pellet supportJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2007Li Wang Abstract Titanium silicalite-1 (TS-1) films were prepared on SiO2 pellet supports via an in situ hydrothermal synthesis method and were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and 29Si magic angle spinning nuclear magnetic resonance (Si MAS NMR). The growth time of TS-1 film had a strong effect on its morphology and the thickness and size of the crystals. The uniformity and thickness of TS-1 films increased with increase of growth times. The epoxidation of allyl chloride (ACH) with dilute hydrogen peroxide to form epichlorohydrin (ECH) over the TS-1 films was carried out in a fixed bed reactor. The conversion of ACH and the selectivity to ECH over the TS-1 films of the second growth were higher than that of the first growth, the third and the fourth growth. And the conversion and selectivity as a function of time-on-stream gave a good stable performance in an extended test up to at least 19 h. The final steady-state conversion and selectivity were approximately 86% and 55%, respectively. Copyright © 2007 Society of Chemical Industry [source] LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD-GROWTH FORESTS OF ALASKA,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2000A. C. Johnson ABSTRACT: More than 300 landslides and debris flows were triggered by an October 1993 storm on Prince of Wales Island, southeast Alaska. Initiation, runout, and deposition patterns of landslides that occurred within clearcuts, second-growth, and old-growth forests were examined. Blowdown and snags, associated with cedar decline and "normal" rates of mortality, were found adjacent to at least 75 percent of all failures regardless of land use. Nearly 50 percent of the landslides within clearcuts occurred within one year following timber harvest; more than 70 percent of these sites had hydrophytic vegetation directly above failures. In following the runout paths of failures, significantly more erosion per unit area occurred within clearcuts than in old-growth forests on slopes with gradients from 9 to 28* (16 to 54 percent). Runout length, controlled by hillslope position within deglaciated valleys, was typically longer in old-growth forests than in second growth and clearcuts (median values were 334, 201, and 153 m, respectively). Most landslides and debris flows deposited in first-and second-order channels before reaching the main stem channels used by anadromous fish. Slide deposits in old-growth forests were composed of a higher proportion of woody debris than deposits derived from slides in second growth or clearcuts. [source] Molecular biology of grape berry ripeningAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2000SIMON P. ROBINSON Abstract Grapevines produce non-climacteric fruit that exhibit a double sigmoidal pattern of growth. Ripening occurs during the second growth phase when grapes change colour, start to soften, accumulate reducing sugars, metabolise organic acids and synthesise flavour compounds. Unlike many other fruit, grapes ripen while the berries are still expanding, and as with most non-climacteric fruit, ripening does not appear to be controlled by ethylene. Sugars and amino acids that accumulate in grapes during ripening are imported via the phloem, while many secondary metabolites are synthesised within the berry itself. Grapes import sucrose but accumulate hexoses. Conversion of sucrose to hexoses is most likely catalysed by invertase. cDNAs encoding vacuolar invertases have been isolated from grape berries. Expression of these genes and an increase in invertase activity occur before veraison, so it seems unlikely that synthesis of this enzyme is a controlling factor for sugar accumulation during ripening. Proteins that transport sugars into the berry vacuole may regulate sugar accumulation, and cDNAs encoding both sucrose and hexose transporters have been isolated from ripening grape berries. Determination of the role of these transporters may reveal the pathway of sugar accumulation in grapes. Anthocyanins are only synthesised in the skin of red grapes after veraison. Analysis of the patterns of expression of genes in the flavonoid pathway has shown that there is a dramatic increase in expression of many of these genes in skin cells at veraison. Expression of the gene encoding a glycosyl transferase involved in the lasts steps of anthocyanin synthesis was absolutely correlated with anthocyanin synthesis and may explain the lack of anthocyanin synthesis in white grapes and in the flesh of most red grapes. We infer that the synthesis of anthocyanins is regulated at the transcription level and is likely to be controlled by regulatory genes. Softening of fruit generally results from changes in the properties of cell walls. Analysis of the cell walls of grapes during ripening suggests that there are no dramatic changes in polysaccharide composition but modification of specific components may contribute to softening. A number of proteins are newly synthesised in grapes during ripening and several of these proteins have now been identified. The most abundant are pathogenesis-related (PR) proteins, including chitinases and thaumatin-like proteins. Expression of genes encoding a number of PR proteins increased dramatically in grapes during ripening. It is not clear what role the PR proteins play during ripening but they may provide resistance to pathogens. Differential screening of a post-veraison grape berry cDNA library has also identified ripening-related genes, some of which encode proline-rich cell wall proteins. Other grape ripening-related genes have homologues that are induced by stress in other plants. These studies indicate that a dramatic change in gene expression occurs in grape berries at veraison and suggest that ripening involves a coordinated increase in transcription of a number of different genes. [source] | ||||||||||