Comparative study on sizing properties of amphoteric starch and phosphorylated starch for warp sizing

By varying the ratios of N-(3-chloro-2-hydroxypropl) trimethylammonium chloride and orthophosphate to starch, a series of amphoteric starch with different degree of substitution (DS) were prepared for evaluating sizing effect of amphoteric starch for cotton warps. The amphoteric starch contained quaternary ammonium and phosphate groups simultaneously, and was set to electric neutrality by varying relative quantity of anionic and cationic groups in order to prevent adverse effects of negative and positive charges. The influence of amphoteric modification of starch on the adhesion to cotton fibers was assessed by measuring tensile strength and work-to-break of slightly sized cotton roving and comparing the adhesion of amphoteric starch with those of phosphorylated one. Comparison on mechanical performances of amphoteric starch film over phosphorylated one was evaluated in terms of tensile strength, breaking extension and wear loss of starch film. The properties such as increase in tensile strength, loss in elasticity, abrasion resistance, and hairiness of cotton yarns sized with amphoteric starch were evaluated through control tests by the comparison with those of phosphorylated one. When zeta potential of amphoteric starch was set close to zero, the adhesion increased and the properties of sized yarns enhanced as the modification level increased. The amphoteric starch was evidently superior to phosphorylated one in improving the quality of sized cotton yarns. The amphoteric starch with neutral zeta potential and DS levels of 0.02–0.03 for quaternary ammonium groups and phosphate ones, respectively, could be applied to size cotton warp yarns for the improvement of yarn quality.     

The influence of thermal stabilization stage on the molecular structure of polyacrylonitrile fibers prior to the carbonization stage

Structural transformation from a linear chain structure to crosslinked chain structure, occuring during the thermal stabilization stage of carbon fiber manufacture, was followed through the use of infrared spectroscopy, differential scanning calorimetry (DSC), elemental analysis and gel-fraction measurements. The results obtained from the analysis of IR spectroscopy showed the gradual and continuous loss of intensity of the nitrile (C≡N) vibration at 2242 cm⁻¹ closely associated with the cyclization reactions whereas the intensity loss of the methylene (CH₂) groups vibration around 2920–2939 cm⁻¹ has been attributed to the loss of hydrogen atoms as part of the dehydrogenation reactions. The dehydrogenation index, evaluated using the absorbance ratio of A₁₄₅₂/A₁₃₆₈, also indicated the gradual loss of hydrogens in agreement with decreasing hydrogen content with progressing stabilization process. IR spectroscopy also showed the emergence of new absorption bands attributed to the formation of crosslinked ladder-like structure in the 1590–1600 cm⁻¹ region. The amount of newly formed crosslinked structure was characterized using DSC conversion index, IR conversion index and gel-fraction measurements. The results are compared and discussed in detail.     

Resource availability through rainwater harvesting influenced vegetation diversity and herbage yield in hillslope of Aravalli in India

Recent decline in biological diversity has stimulated the research on the effects of resource conservation on biodiversity and vice versa. We examined soil water and nutrients influenced by rainwater harvesting (RWH) in hillslope and its effects on herbage diversity and productivity at up (USP), middle (MSP) and lower position (LSP) in 75 plots, each of 700-m² area laid in < 10%, 10%–20% and > 20% slopes, respectively. The five RWH treatments were Contour trench (CT), Gradonie (G), Box trench (BT), V-ditch (VD) and control. Soil water content (SWC), species number, population, diversity and herbage yield increased (P < 0.05) downward suggesting positive relations between soil resource and diversity/productivity. The highest species number, population, richness and diversity in 10%–20% slope were associated with soil water usage and NO₃-N and NH4-N concentrations. SWC was 5.0%–19.0% greater in RWH areas than in control influencing herbage species, population, growth and yields. The increase in diversity and yields was the highest (P < 0.05) in V-ditch reinforced by soil fertility. The positive effect of diversity on yield increased with resources, and the effect was compositional rather than that of species richness. Conclusively, slope gradient and soil texture influenced herbage regeneration, diversity and productivity, which were positively affected by existing soil fertility and applied RWH and mobilizing soil water and nutrients. The effect of V-ditch was the highest on composition and yield. Thus, RWH enhanced herbaceous vegetation and restoration of degraded forest/rangelands. But long-term effects of diversity in restoring ecosystem productivity could be established through long-term data collections on optimum water/nutrient usage, diversity and productivity.     

Establishment of native <Emphasis Type="Italic">Eucalyptus pauciflora</Emphasis> and exotic <Emphasis Type="Italic">Eucalyptus nitens</Emphasis> on former grazing land

The success of tree plantings in agricultural landscapes within dry and variable rainfall regions is often below expectations. The aims of this study were to investigate techniques for establishing a local native species (Eucalyptus pauciflora) and an exotic species (E. nitens) in the Midlands of Tasmania, a tree-denuded region that has been grazed for over 100 years in Australia. We established trials at the Sorrel Springs and Woodland Park properties. We compared six establishment techniques: control; understorey nurse planting; spot burn; mulch; tree-guard and; self-watering tree-guard. Three months, 1 and 6 years after planting we measured tree height, health index and mortality. At Sorrell Springs tree-guarded treatments had greater height than other treatments at year one, but there were no effects of treatment at year six on height, health or mortality. At Woodland Park mulch, burn and tree-guarded treatments had greater height 1 and 6 years after planting. At year six tree-guarded treatments had lower mortality than other treatments. At Sorrell Springs height of E. nitens was greater than E. pauciflora at year one but not at year six. At Woodland Park height of E. nitens was generally greater at year six but having almost double the incidence of mortality relative to E. pauciflora. We conclude that expensive tree-guarding is only warranted where high browse pressure is expected and that on such sites species with tough leaves that are resistant to browsing should be considered. Further that in environments marginal for growing trees, best practice establishment technique is generally as effective as additional treatments of understorey nurse planting, spot burning or mulching.     

Is zinniol a true phytotoxin? Evaluation of its activity at the cellular level against <Emphasis Type="Italic">Tagetes erecta</Emphasis>

Zinniol, a non-host selective phytotoxin commonly produced by fungi of the Alternaria genus, has been reported as the metabolite responsible for the phytotoxicity of the lipophilic fraction of A. tagetica. While both the lipophilic fraction and zinniol have been shown to produce necrosis on leaves of susceptible marigold (Tagetes erecta) plants, the true role of zinniol in the infectious process remains uncertain. Using marigold cell cultures as a model, we evaluated the effects of zinniol and the lipophilic fraction at the cellular level and showed that pure zinniol is not markedly phytotoxic at concentrations known to induce necrosis in leaves of T. erecta. Moreover, the effects of zinniol on cell membranes and DNA fragmentation are less intense than those caused by the lipophilic fraction. These results suggest that zinniol may not play a significant role in the A. tagetica–T. erecta interaction and, consequently, its classification as a non-host selective phytotoxin is questionable.     

Short-term effects of overstory reduction and slash mulching on ground vegetation in a Mediterranean Aleppo pine woodland

The short-term effects of forest overstory reduction and slash mulching on ground vegetation were analysed in a Mediterranean Aleppo pine reforested woodland on degraded agricultural land in south-east Spain. This sort of practice is becoming common in the Mediterranean basin to guard against forest fires, but very few attempts have been made to analyse its effect upon biodiversity. The data concerning floristic richness and above-ground biomass of species were measured as dependent variables in 0.5 × 0.5 m quadrats in an overstory reduction versus control area (treatment factor) during the spring of 2006. The data were analysed by ANCOVA, in which slash-mulch weight was introduced as covariate. Relationships between dependent variables and slash-mulch weight were examined using linear regression, and variations in floristic composition were ascertained by means of principal component analysis (PCA). A total of 32 ruderal herbaceous species were recorded, none of which was exotic. In spite of some methodological constraints (i.e. low number of samples and data from a non-replicated case study), the results of our study point to the conclusion that most of these species were found more frequently in the overstory-reduction treatment compared to the control area, and that only a few species clearly preferred the control treatment. In general, overstory reduction led to a significant increase both in floristic richness and above-ground biomass. Slash mulching, on the other hand, encouraged the appearance of a greater quantity of above-ground biomass (in different ways depending upon treatment), although species richness did not improve, even to the extent of declining in the control area. On the basis of our findings, overstory reduction seems to increase species richness and productivity in dense Mediterranean afforestations on degraded agricultural land, at least in the short-term. Large quantities of mulch accompanied by high tree density would seem not to favour species richness.     

Effect of height-to-diameter ratio on stem stiffness of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) cultivars

The lumber from sugi plantations in Japan displays large intra- and intertree variation in mechanical properties, even within a stand. These variations seem to be induced by the effects of the characteristics of cultivars as well as the effects of growth traits on mechanical properties. Therefore, the effects of growth traits on mechanical properties per cultivar need to be precisely examined. In this study, we focused on the effects of growth traits, especially height-to-diameter ratio (H/D ratio), on stem stiffness per cultivar. Sixteen cultivars were classified into three groups according to the relationships between stem stiffness and growth traits. In cultivars that showed a close correlation between growth traits and stem stiffness, it was assumed that stem stiffness could be controlled to a certain extent by silvicultural practices using the H/D ratio as an indicator. In cultivars that showed a weak correlation between growth traits and stem stiffness, selecting cultivars for the production of logs with higher mechanical properties seemed to be effective; in this study, Kumotoshi, Tanoaka, and Edanaga were found to be suitable. Tree age and site index may be important factors for producing wood with higher mechanical properties.     

Influence of characteristics and extension of a forest road network on the supply cost of forest woodchips

A forest road network in northeastern Italy was explored by field investigations to evaluate the cost of covering annual demand of woodchips according to three scenarios. The first scenario (A) considered the current extent of the forest road network (mainly tractor road) and the associated qualitative characteristics; the second scenario (B) evaluated the possibility of increasing the availability of the technical amount of forest biomass by extending the forest road network by three tractor roads (3.9 km); the third scenario (C) considered the impact on woodchip supply of converting 9.3 km of tractor forest road into truck forest road. At a woodchip price of 60 € t⁻¹, the cost–supply curve of scenario C indicated a woodchip amount of 2886 t year⁻¹, which was 561 t year⁻¹ greater than scenario A and 161 t year⁻¹ greater than scenario B.     

Multi-scaled habitat considerations for conserving urban biodiversity: native reptiles and small mammals in Brisbane,Australia

The rapid expansion of the world’s urban population is a major driver of contemporary landscape change and ecosystem modification. Urbanisation destroys, degrades and fragments native ecosystems, replacing them with a heterogeneous matrix of urban development, parks, roads, and isolated remnant fragments of varying size and quality. This presents a major challenge for biodiversity conservation within urban areas. To make spatially explicit decisions about urban biodiversity conservation actions, urban planners and managers need to be able to separate the relative influence of landscape composition and configuration from patch and local (site)-scale variables for a range of fauna species. We address this problem using a hierarchical landscape approach for native, terrestrial reptiles and small mammals living in a fragmented semi-urban landscape of Brisbane, Australia. Generalised linear modelling and hierarchical partitioning analysis were applied to quantify the relative influence of landscape composition and configuration, patch size and shape, and local habitat composition and structure on the species’ richness of mammal and reptile assemblages. Landscape structure (composition and configuration) and local-scale habitat structure variables were found to be most important for influencing reptile and mammal assemblages, although the relative importance of specific variables differed between reptile and mammal assemblages. These findings highlight the importance of considering landscape composition and configuration in addition to local habitat elements when planning and/or managing for the conservation of native, terrestrial fauna diversity in urban landscapes.     

Effects of spatial habitat heterogeneity on habitat selection and annual fecundity for a migratory forest songbird

Understanding how spatial habitat patterns influence abundance and dynamics of animal populations is a primary goal in landscape ecology. We used an information-theoretic approach to investigate the association between habitat patterns at multiple spatial scales and demographic patterns for black-throated blue warblers (Dendroica caerulescens) at 20 study sites in west-central Vermont, USA from 2002 to 2005. Sites were characterized by: (1) territory-scale shrub density, (2) patch-scale shrub density occurring within 25 ha of territories, and (3) landscape-scale habitat patterns occurring within 5 km radius extents of territories. We considered multiple population parameters including abundance, age ratios, and annual fecundity. Territory-scale shrub density was most important for determining abundance and age ratios, but landscape-scale habitat structure strongly influenced reproductive output. Sites with higher territory-scale shrub density had higher abundance, and were more likely to be occupied by older, more experienced individuals compared to sites with lower shrub density. However, annual fecundity was higher on sites located in contiguously forested landscapes where shrub density was lower than the fragmented sites. Further, effects of habitat pattern at one spatial scale depended on habitat conditions at different scales. For example, abundance increased with increasing territory-scale shrub density, but this effect was much stronger in fragmented landscapes than in contiguously forested landscapes. These results suggest that habitat pattern at different spatial scales affect demographic parameters in different ways, and that effects of habitat patterns at one spatial scale depends on habitat conditions at other scales.