Three herbaceous regimes were established, using herbicides, to examine the effects of interference on growth and biomass partitioning in loblolly pine (Pinus taeda L.). Trees were sampled near Auburn and Tallassee, AL. Trees at the Auburn site grown with low weed interference (LWI) had 4, 10, 10, 8, and 4 times greater total aboveground biomass than did trees with high weed interference (HWI) for ages one through five, respectively. Medium weed interference (MWI, Auburn site only) resulted in three times greater biomass the first 4 yr and two times greater total biomass by the fifth year compared to trees grown with HWI. Trees growing with LWI were 5, 8, 10, and 6 times larger than those with HWI for ages one through four, respectively, at the Tallassee site. At all levels of interference, the percentage of total biomass in foliage decreased, and stem and branch components increased, with increasing tree size at both sites. Trees growing with HWI had a lower percentage of total biomass in foliage and a greater percentage of total biomass in stem than those growing with LWI when compared over a common size. Growth efficiency per tree, expressed as annual increase in stem biomass per unit leaf area (g m−2), was slightly greater for trees growing with LWI compared to HWI when leaf area index (LAI3, total surface) was less than 0.2. For LAI values greater than 0.2 the relationship was reversed. The latter contradicts the idea that growth efficiency can be used as a measure of vigor for young loblolly pine. Changes in carbon partitioning to the development of leaf area are suggested to be driving the accelerated growth responses associated with a reduction of weed interference.

Stands of four-year-old loblolly pines grown with and without herbaceous competition were compared to determine whether early increases in soil moisture and plant water status had been maintained throughout the first four years. Non-weeded stands tended to have greater soil moisture than weeded stands, although these differences were never statistically significant (P > 0.05). Plant water potential was remarkably similar between treatments, as were photosynthesis and stomatal conductance. The increase due to weed control in foliage production early in stand development apparently caused a depletion in available soil moisture to levels similar to non-weeded stands. Therefore, the direct benefit of increased soil resources with weed control is short lived.

This article is an executive summary of a report from the Centers for Disease Control and Prevention Ventilator-Associated Pneumonia Surveillance Definition Working Group, entitled “Developing a new, national approach to surveillance for ventilator-associated events” and published in Critical Care Medicine. The full report provides a comprehensive description of the Working Group process and outcome.

In September 2011, the Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group to organize a formal process for leaders and experts of key stakeholder organizations to discuss the challenges of VAP surveillance definitions and to propose new approaches to VAP surveillance in adult patients (Table 1).

We present first imaging results from the PALM-3000 adaptive optics system and PHARO camera on the Hale 5 m telescope. Observations using a vector vortex coronagraph have given us direct detections of the two-ring dusty debris system around the star HD 141569. Our observations reveal the inner clearing in the disk to unprecedentedly small angular separations, and are the most sensitive yet at the H and K bands. We are for the first time able to measure and compare the colors of the scattered light in the inner and outer dust rings, and find that the outer ring is significantly bluer than the inner ring.

The immunoglobulins (IgGs) for beta amyloid (Aβ) and receptors for the advanced glycation end products (RAGE) have previously been shown to be related to memory and language measures in a mixed neurological sample of older adults. In this study, we examined group differences in Aβ and RAGE IgGs, as well as the relationship between both IgGs and cognitive performance in nondiabetic older adults with normal cognition, mild cognitive impairment (MCI), and probable Alzheimer’s disease (AD). We found RAGE and Aβ levels to be elevated in some AD participants, leading to significant AD–control group differences. While there was an overall correlation between both IgG levels and global cognition across all three groups, this relationship was largely attributable to group differences in cognition, highlighted by considerable variability within groups in the relationship between IgG levels and cognition. While findings do not support a consistent relationship between cognition and either IgG, further research with larger samples is needed to better characterize cognitive differences between AD participants with high versus low Aβ and RAGE titers. (JINS, 2010, 16, 672–678.)

Internationally, traditional approaches to social assistance (welfare) have increasingly been replaced with ‘active’ labour market policies. Alongside other industrialised countries, Canada embraced this shift, with its emphasis on the ‘shortest route’ to paid employment.

There has been little research on the outcomes of these dramatic changes in Canada, especially longer term. This article explores the post-welfare labour market experiences of people who were on social assistance in Canada in 1996. It uses the longitudinal micro-data files of the Survey of Labour and Income Dynamics (SLID) from Statistics Canada, which tracks a panel of recipients over five years. We examine the mixing of work and welfare, the transition from welfare to work, and selected labour market indicators – primarily hours of work and wages – that those in receipt of social assistance face in assuming paid work.

Those leaving welfare for work face precarious employment opportunities. Leavers earn lower wages, work fewer hours and consequently have lower annual earnings than non-recipients. Over time the gap narrows but remains significant, even after six years. Returns to welfare are frequent. Overall, even after six years most social assistance recipients remained marginalised in the periphery of the labour market.

This paper describes a study to assess the validity of a brief household survey measure of psychic distress (PSYDIS). The measure classifies persons according to their pattern of scores on four dimensions, including anxiety and depression. Study subjects were interviewed first respondents from the general population in a cross-sectional household survey. Then, according their ratings on PSYDIS, subsamples were selected for psychiatric evaluation in a clinic a few weeks later. The survey ratings of 287 persons were compared with evaluations of the same persons experienced psychiatrists. Overall levels of concordance ranged from 76% to 80%, depending the psychiatric criterion used. Concordance was very high for women; it was lower for men for persons classified as High on PSYDIS

We then applied two analytic strategies for increasing agreement between the clinical judgements and the clinical ratings. Strategy number I augmented the symptom checklist data with additional survey data on the subject's history of episodes of distress. Strategy II revised procedures for constructing the PSYDIS typology by (1) using more rigorous cutting point scores on the component scales, and (2) using a non-typological method of classification. The first strategy improved agreement between the clinic and survey measures; the second did not. The paper also compares PSYDIS with other brief symptom checklist measures.

A new extractant for the separation of actinide(III) and lanthanide(III), bis(o-trifluoromethylphenyl)phosphinic acid (O-PA) was synthesized. The synthetic route employed mirrors one that was employed to produce the sulfur containing analog bis(o-trifluoromethylphenyl)dithiophosphinic acid (S-PA). Multinuclear NMR spectroscopy was used for elementary characterization of the new O-PA derivative. This new O-PA extractant was used to perform Am(III)/Eu(III) separations and the results were directly compared to those obtained in identical separation experiments using S-PA, an extractant that is known to exhibit separation factors of ∼100,000 at low pH. The separations data are presented and discussed in terms comparing the nature of the oxygen atom as a donor to that of the sulfur atom in extractants that are otherwise identical.

This paper examines the experiences of immigrants in Toronto as they pass through, and leave, Ontario Works (OW), a ‘Work First’ approach to social assistance that prioritizes rapid labour force attachment. We examine the Ontario Works activities of immigrants, compared to native born Canadians, and their respective post-OW job characteristics. We find that immigrants experience a significant relative wage disadvantage after participation, and substantially less wage growth when moving to the second post-welfare job. We conclude that Ontario Works, like most ‘work first’ employment programs, is ill-suited to addressing earnings disadvantage among immigrants. We suggest that programs ‘beyond work first’, though not targeted specifically towards immigrants, might nevertheless offer more assistance. The recurring wage disadvantage, however, would remain unaddressed and might require more direct intervention.

New poly(fluorene-thiophene) alternating copolymers are described in which either the dioctylfluorene or bithiophene units in poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) are replaced by other fluorene or thiophene-based groups, respectively. Improvements in solubility are realized when the bithiophene unit of F8T2 is replaced by dihexylterthiophene or dihexylpentathiophene units. Melting temperatures are also lowered by 50 – 100°C in these polymers when compared to F8T2. Replacement of the bithiophene unit of F8T2 with a dihexylpentathiophene unit also results in a significant improvement in hysteresis (< 2 V vs. 3.5 – 5 V for F8T2). Initial results are also reported on the thermal cleavage of the C8 side groups of F8T2, which yields an insoluble polymeric semiconductor film that continues to exhibit transistor switching characteristics as part of a bottom gate device.

Polyfluorenes are a class of polyaromatic macromolecules that are characterized by an alternating backbone structure that consists of a 9,9-dialkylfluorene unit in combination with another aromatic group. The nature of this aromatic unit plays a key role in the electronic properties of the polymers. For example, polyfluorenes which combine chromophoric and charge transporting aromatic units have received a great deal of attention over the last several years as the emissive layer in polymeric light emitting diodes [LUMATION* Light-Emitting Polymers (LEPs)]. More recently, polyfluorenes have also been designed to perform as the organic semiconducting layer in polymeric field effect transistors (PFETs). This effort has led to a class of polymeric semiconductors with an excellent combination of charge mobility, environmental stability, and processability. One such polymer is the polyfluorene based on an alternating backbone of 9,9-dioctylfluorene and 2,2'-bithiophene units. This material has been shown to have charge mobilities as high as 0.02 cm2/V-s with current on/off ratios of up to 106. The poly(fluorene-bithiophene) is more resistant to doping by atmospheric oxygen than other polymeric semiconductors such as poly(3-hexylthiophene). Inks based on solutions of poly(fluorene-bithiophene) in xylene, mesitylene, and other solvents have also been prepared. The paper will focus on the recent advances in the synthesis, fabrication, and electrical characterization of poly(fluorene-bithiophene). *Trademark of The Dow Chemical Company