Growth of six planted tree species under various cultural treatments on former agricultural bottomlands

Falling soybean prices in the mid-1970s resulted in extensive abandonment of agricultural wetlands in the Mississippi Valley. Research has been conducted on the reforestation of these sites, but few studies have documented the long-term results of reforestation practices. This study was initiated to determine tree species and cultural treatments best suited to west Tennessee\u27s former agricultural bottomlands. The effects of seed source, fertilization, disking and mowing on sweetgum (Liquidambar styraciflua L.), American sycamore (Platanus occidentalis L.) and green ash (Fraxinus pennsylvanica Marsh.) were examined 18 years after planting. Seventeen-year-old cherrybark oak (Quercus pagoda Raf), yellow-poplar (Liriodendron tulipifera L.) and loblolly pine (Pinus taeda L.) under fertilization, disking and mowing also were examined. Variations in soil series and bulk density and the effects of water table depth on tree growth were analyzed. Overall survival was significantly higher for sweetgum (93%) and green ash (95%) than for sycamore (88%). Height growth of sweetgum was significantly greater than sycamore, which was significantly greater than that of green ash. Seed source (Virginia Coastal Plain vs. Louisiana Gulf Coast) had no effect on the growth of sycamore or sweetgum. Height and dbh of sweetgum, sycamore and green ash were significantly increased by fertilization only on plots that were not disked or mowed. Disking and mowing significantly increased the growth of unfertilized trees more than that of fertilized trees. Survival was 92%, 64% and 63% for yellow-poplar, cherrybark oak and loblolly pine, respectively. Growth of loblolly pine was significantly greater than that of cherrybark oak. The growth and survival of yellow-poplar, cherrybark oak and loblolly pine were not affected by cultural treatments. Natural regeneration on the same site resulted in dense stands (3,445 trees/acre and 4,340 trees/acre) dominated by sweetgum. The combination of fertilization and mowing significantly increased soil bulk density. Soils were much more variable than prior soil surveys indicated. Although a shallower water table increased survival of sweetgum and sycamore, growth was increased for these two species on better-drained soils

Relationships Among Foliar Phenology, Radial Growth Rate, and Xylem Density in a Young Douglas-Fir Plantation

We related intra-annual patterns in radial growth rate and xylem density to foliar phenology and second growth flushes in a young Douglas-fir plantation in western Washington. Three foliar maturity classes were defined: (1) shoots and needles elongating; (2) elongation complete, needles maturing; and (3) needles mature. Diameter growth rate had two peaks, one about the time of budbreak and one when foliage was in maturity Class 2. There was a limit to the maximum periodic density of xylem formed at a given rate of diameter growth; as growth rate increased, maximum periodic density decreased. Although xylem density profiles varied widely among individual trees, xylem density differed significantly among foliar maturity classes, increasing 16% from Class 1 to 2 and 60% from Class 2 to 3. Diameter growth rate of second-flushing trees was significantly greater in July compared with trees with no second flush, but we detected no relationships between second-flushing and xylem density patterns or false rings. Although the young trees in this study did not show distinct earlywood-latewood transitions, fully mature foliage (Class 3) was associated with formation of xylem exhibiting characteristics of latewood: greater density, reduced diameter growth rate, reduced tracheid radial diameter, and less interannual growth variation

Determinants of electrical energy demand for a state; methodology and system simulation

The determinants of electrical energy demand for the State of Oregon are represented in a mathematical model. This model is structured to operate in parallel with a computer simulation model of the state and is utilized independently to investigate electrical energy consumption during various scenarios of economic activity and energy prices. The introductory chapters discuss the importance of the inclusion into energy forecasts of the effects of significant changes in economic and demographic variables as well as consumer responses to increasing energy prices. Alternate methodologies used in forecasting are reviewed. It is argued that the determinants of electricity demand should be viewed as interrelated elements of a socio-economic system and must be addressed in concert with one another. The Oregon State Simulation Model (OSSIM) and the system simulation methodology employed in its development are described. Chapter four presents the data base, structure, and dynamics of the electrical energy demand model. Intensiveness of electricity use and economic activity are exhibited separately, to demonstrate whether increases in consumption are due to changes in intensiveness, to economic growth, or to both and in what proportion. Increasing energy prices induce electricity conservation, interfuel substitution, and changes in appliance saturation trends. These phenomena are modeled explicitly, recognizing that each can affect intensiveness of use and can be characterized by different time constants and limits. The following four chapters develop electrical energy intensiveness functions for thirty-seven consumer categories which are divided among four major sectors. The industrial sector consists of nineteen two-digit SIC groups and three irrigation regions; twelve household appliances and one residual group are included in the residential sector; the commercial sector covers all service activities with the exception of street/highway illumination, which composes the transportation sector. Underlying causes of changing electrical energy intensiveness are explored and price-independent projections of intensiveness are proposed. These projections are linear functions of time in the non-residential categories and sigmoidal functions in twelve residential categories. Results of model operation with exogenous functions of economic activity are discussed in the concluding chapter, together with a description of sensitivity testing and validation criteria. Scenarios investigated demonstrate the significance of the detailed representation of consumer responses to energy price changes. Model utility appears to lie in the ability to illustrate causes of changes in electricity consumption growth rate, to assess alternate scenarios of energy prices, and--when utilized in concert with the OSSIM--to estimate electrical energy requirements based upon self-consistent scenarios of underlying economic activity

The ProTides boom

The masking of nucleoside phosphate and phosphonate groups by an aryl motif and an amino acid ester, nowadays known as the ‘ProTide’ technology, has proven to be effective in the discovery of nucleotide therapeutics. Indeed, this technology, which was invented by Chris McGuigan in the early 1990s, has inspired the discovery of two FDA-approved antiviral nucleotide drugs, and many more are currently undergoing (pre)clinical development. The usefulness of this technology in the discovery of nucleotide therapeutics is showcased in this Highlight by discussing the ProTides development and the various ProTides that have reached clinical trials

Identifying predictors of attitudes towards local onshore wind development with reference to an English case study

The threats posed by climate change are placing governments under increasing pressure to meet electricity demand from low-carbon sources. In many countries, including the UK, legislation is in place to ensure the continued expansion of renewable energy capacity. Onshore wind turbines are expected to play a key role in achieving these aims. However, despite high levels of public support for onshore wind development in principle, specific projects often experience local opposition. Traditionally this difference in general and specific attitudes has been attributed to NIMBYism (not in my back yard), but evidence is increasingly calling this assumption into question. This study used multiple regression analysis to identify what factors might predict attitudes towards mooted wind development in Sheffield, England. We report on the attitudes of two groups; one group (target) living close to four sites earmarked for development and an unaffected comparison group (comparison). We found little evidence of NIMBYism amongst members of the target group; instead, differences between general and specific attitudes appeared attributable to uncertainty regarding the proposals. The results are discussed with respect to literature highlighting the importance of early, continued and responsive community involvement in combating local opposition and facilitating the deployment of onshore wind turbines. (C) 2009 Elsevier Ltd. All rights reserved

Counting young carers in Switzerland – a study of prevalence

An online survey of children in school grades 4–9 (mostly aged 10–15) was conducted in order to determine the prevalence of young carers in Switzerland using a 2‐stage stratified sampling approach. 4082 respondents were drawn from 230 schools. A total of 3991 respondents were included in the analysis and of these 307 (7.7%) were identified as young carers. The population estimate of prevalence was 7.9 per cent. This suggests that there are around 38 400 young carers in school grades 4–9 in Switzerland. Extrapolating to the 9–16 age group gives a figure of almost 51 500

A Nonvolatile MOSFET Memory Device Based on Mobile Protons in SiO(2) Thin Films

It is shown how mobile H{sup +} ions can be generated thermally inside the oxide layer of Si/SiO{sub 2}/Si structures. The technique involves only standard silicon processing steps: the nonvolatile field effect transistor (NVFET) is based on a standard MOSFET with thermally grown SiO{sub 2} capped with a poly-silicon layer. The capped thermal oxide receives an anneal at {approximately}1100 C that enables the incorporation of the mobile protons into the gate oxide. The introduction of the protons is achieved by a subsequent 500-800 C anneal in a hydrogen-containing ambient, such as forming gas (N{sub 2}:H{sub 2} 95:5). The mobile protons are stable and entrapped inside the oxide layer, and unlike alkali ions, their space-charge distribution can be controlled and rapidly rearranged at room temperature by an applied electric field. Using this principle, a standard MOS transistor can be converted into a nonvolatile memory transistor that can be switched between normally on and normally off. Switching speed, retention, endurance, and radiation tolerance data are presented showing that this non-volatile memory technology can be competitive with existing Si-based non-volatile memory technologies such as the floating gate technologies (e.g. Flash memory)