Influence of oxygen plasma pre-treatment on the water repellency of cotton fibers coated with perfluoroalkyl-functionalized polysilsesquioxane

Oxygen plasma pre-treatment was applied to cotton fabric with the aim of improving the water repellency performance of an inorganic-organic hybrid sol-gel perfluoroalkyl-functionalized polysilsesquioxane coating. Cotton fabric was pre-treated with low-pressure oxygen plasma for different treatment times and operating powers. Afterward, 1H,1H,2H,2H-perfluorooctyltriethoxysilane (SiF) was applied to the cotton fabric samples using the pad-dry-cure method. The surfaces of the untreated and modified cotton fibers were characterised using Fourier transform infrared spectroscopy, Xray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water repellency of the SiF-coated fabric samples was evaluated using static and sliding contact angle measurements with water. The results show that the plasma treatment with the shortest treatment time (10 s) and the lowest operating current (0.3 A) increased the atomic oxygen/carbon ratio of the cotton fiber surface from 0.6 to 0.8 and induced the formation of a nano-sized grainy surface. Increasing the plasma treatment time and/or operating current did not intensify the surface changes of the cotton fibers. Such saturation effects were explained by the large influence of reactive oxygen atoms during the plasma treatment. The measured static water contact angles on the surface of the untreated and plasma pre-treated and SiF-coated cotton fabrics showed that the oxygen plasma pre-treatment enabled the increase of the water contact angle from 135° to ≈150°, regardless of the applied plasma treatment time and discharge power. This improvement in the hydrophobicity of the SiF coating was followed by a decrease in the sliding angle of water droplets by more than 10° compared to the plasma untreated and SiF-coated sample characterized by a water sliding angle of 45°. Additionally, measurements of the water sliding angle revealed that the increase of the static contact angle from 149° to 150° corresponded to a drop of the water sliding angle from 33 to 24°, which suggests that the plasma pre-treatment of 20 s at an operating current of 0.3 A produced the best water-repellent performance of the SiF-coated cotton fabric.     

Polyhydroxyamic acid from 3,3′-dihydroxybenzidine and pyromellitic dianhydride as a fire-safe polymer

In order to assess the potential of the hydroxy-containing polyamic acid (PHAA) synthesized from 3,3′-dihydroxy benzidine and pyromellitic dianhydride for a fire-safe polymer, the cyclization pathway of PHAA has been investigated using a model compound prepared from 2-aminophenol and phthalic anhydride. The reaction was monitored by¹H-nuclear magnetic resonance. N-(2-hydroxyphenyl)phthalamic acid is converted to N-(2-hydroxyphenyl)phthalimide at ca. 175°C, showing endothermic reaction. The imide structure is rearranged to the benzoxazole structure over ca. 400°C. These results are similar with that of PHAA. According to pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) data, water and carbon dioxide are released during the cyclization and rearrangement reaction. One DMAc molecule is complexed with one carboxyl acid group in PHAA, which accelerates the imidization process to release more easily the flame retardant, water.     

Diversity of Stored Grain Insect Pests in the Logone Valley, from Northern Cameroon to Western Chad Republic in Central Africa

Insects are major pests of stored grains. In sub Sahara Africa, stored grain insect pests are mainly Coleoptera or Lepidoptera. In the Logone Valley, area covering the Far North Region of Cameroon and South-West of Chad, to our knowledge, the diversity of insect pests noxious to stored products is not established. These beetles and weevils （Insecta：Coleoptera） during their development depreciate food in storage, were able to destroy a whole stock in a very short period of time if no protection of stored food is made. To achieve the diversity of insect pests, inspections of granaries were done in 209 villages of Logone Valley where insect pests were collected and identified. Secondly, the stored grains were sampled in peasant＇s granaries of Logone Valley and reared in incubators in the Unit of Entomological Research of the University of Ngaound6r6. After their emergence, insects were removed, collected and identified. Their noxious efficiency on stored grains is done by the calculation of the density of each insect pests per gram of grains. This study indicates that 12 species of harmful insects attack cereals and leguminous grains in the Logone Valley during storage. The Bruchids were the main insect pests of legumes. Callosobruchus maculatus was the main pest of legume and attacking mainly cowpeas （34.92 bruchids/g of seed） and peanuts （20.75 bruchids/g of seed）. Seven harmful species destroy the cereals. Sitophilus zeamais is the main pest of maize （15.86 weevils/g of maize） and S. oryzae, for sorghum （36.59 weevils/g of maize）. Tribolium castaneum were the main secondary pest. T. castaneum infests both cereals and leguminous. This work summarizes the importance and the diversification of stored grain pests in Logone Valley. Knowing the pest diversity is an important step in the strategy to develop a friendly and ecological control method of these harmful insects.     

California Simulation of Evapotranspiration of Applied Water and Agricultural Energy Use in California

The California Simulation of Evapotranspiration of Applied Water (Cal-SIMETAW) model is a new tool developed by the California Department of Water Resources and the University of California, Davis to perform daily soil water balance and determine crop evapotranspiration (ET c ), evapotranspiration of applied water (ET aw ), and applied water (AW) for use in California water resources planning. ET aw is a seasonal estimate of the water needed to irrigate a crop assuming 100% irrigation efficiency. The model accounts for soils, crop coefficients, rooting depths, seepage, etc. that influence crop water balance. It provides spatial soil and climate information and it uses historical crop and land-use category information to provide seasonal water balance estimates by combinations of detailed analysis unit and county (DAU/County) over California. The result is a large data base of ET c and ET aw that will be used to update information in the new California Water Plan (CWP). The application uses the daily climate data, i.e., maximum (T x ) and minimum (T n ) temperature and precipitation (P cp ), which were derived from monthly USDA-NRCS PRISM data (PRISM Group 2011) and daily US National Climate Data Center (NCDC) climate station data to cover California on a 4 km×4 km change grid spacing. The application uses daily weather data to determine reference evapotranspiration (ET o ), using the Hargreaves-Samani (HS) equation (Hargreaves and Samani 1982, 1985). Because the HS equation is based on temperature only, ET o from the HS equation were compared with CIMIS ET o at the same locations using available CIMIS data to determine correction factors to estimate CIMIS ET o from the HS ET o to account for spatial climate differences. Cal-SIMETAW also employs near real-time reference evapotranspiration (ET o ) information from Spatial CIMIS, which is a model that combines weather station data and remote sensing to provide a grid of ET o information. A second database containing the available soil water holding capacity and soil depth information for all of California was also developed from the USDA-NRCS SSURGO database. The Cal-SIMETAW program also has the ability to generate daily weather data from monthly mean values for use in studying climate change scenarios and their possible impacts on water demand in the state. The key objective of this project is to improve the accuracy of water use estimates for the California Water Plan (CWP), which provides a comprehensive report on water supply, demand, and management in California. In this paper, we will discuss the model and how it determines ET aw for use in water resources planning.     

The complex role of veterinary clinical teachers: how is their role perceived and what is expected of them?

The purpose of this study was to identify personal attributes in veterinary clinical teachers that are valued most by members of their work environment (fellow faculty, clinical training scholars [CTS; residents], undergraduate students, and referring veterinary surgeons) and to determine whether the opinions of these subgroups differed. Faculty (n=50), CTS (n=35), students (n=200), and referring veterinary surgeons (n=25) were presented with a list of 15 potentially desirable attributes. Respondents were asked to rank the three most important and the three least important attributes of effective clinical teachers. Respondents were also asked to select in which of the three main activities (clinical service, teaching, or research) in which clinical teachers currently invest the most and the least effort and in which they should invest the most and the least effort. All respondent groups agreed that "competence-knowledge" was among the most desirable attributes. Faculty, undergraduate students, and referring veterinary surgeons additionally included "enthusiasm" in the top three, whereas CTS regarded "respects independence" as more important. All respondent groups consistently chose "scholarly activity" as one of the three least important characteristics. A similar number of faculty members (38%) expressed that the greatest effort should be invested in clinical service or teaching, and the greatest proportions of CTS (44%) and students (56%) felt that most emphasis should be put on teaching alone. The differences in opinion between respondent groups regarding importance of attributes and emphasis of activity indicate that what is perceived as effective performance of clinical teachers differs depending on the role of those who engage with them.     

Do wildlife habitat strips act as refuges for mature-forest carabid beetle assemblages? A case-study in Tasmanian wet eucalypt forest,Australia

Carabid beetles (Insecta: Coleoptera: Carabidae) were sampled with pitfall traps in central Tasmania to assess the conservation utility of wildlife habitat strips (WHS) in native high-altitude wet eucalypt forest. Sampling followed a Before-After, Control-Impact design, with replicated samples being collected at one control site and two treatment sites, both before harvesting and then again seven to eight years after the harvest that established the WHS. Catches of carabid beetles decreased in harvested areas, but there were great increases in species richness and gross changes in assemblage composition — largely attributable to the colonisation of young-forest specialist species. Assemblages in the control site remained essentially unchanged, and were dominated by mature-forest specialist species. Assemblages in the WHS changed little compared to their pre-harvest condition, but assemblage structure was slightly affected. In this particular landscape, WHS appear to effectively maintain carabid assemblages typical of intact mature native forest, at least in the short-term. A broader and longer-term assessment of the ecological performance of WHS across Tasmania would be required to assess the long-term viability of WHS as a conservation strategy for carabids and other species requiring mature forest.     

Is forest mushroom productivity driven by tree growth? Results from a thinning experiment

? Most of the edible forest mushrooms are mycorrhizal and depend on carbohydrates produced by the associated trees. Fruiting patterns of these fungi are not yet fully understood since climatic factors alone do not completely explain mushroom occurrence.

? The objective of this study was to retrospectively find out if changing tree growth following an increment thinning has influenced the diversity patterns and productivity of associated forest mushrooms in the fungus reserve La Chanéaz, Switzerland.

? The results reveal a clear temporal relationship between the thinning, the growth reaction of trees and the reaction of the fungal community, especially for the ectomycorrhizal species. The tree-ring width of the formerly suppressed beech trees and the fruit body number increased after thinning, leading to a significantly positive correlation between fruit body numbers and tree-ring width.

? Fruit body production was influenced by previous annual tree growth, the best accordance was found between fruit body production and the tree-ring width two years previously.

? The results support the hypothesis that ectomycorrhizal fruit body production must be linked with the growth of the associated host trees. Moreover, the findings indicate the importance of including mycorrhizal fungi as important players when discussing a tree as a carbon source or sink.