BIORATIONAL INSECTICIDE ADOPTION AND CONVENTIONAL INSECTICIDE USE: A SIMULTANEOUS, LIMITED DEPENDENT VARIABLE MODEL

Using data reporting section-level pesticide use for all of Arizona, this study estimates how early-season adoption of new biorational insecticides reduced subsequent broad-spectrum insecticide applications in cotton. The two-stage econometric model accounts for the endogeneity and censoring of the adoption intensity variable. One biorational application substituted for 3.66 broad-spectrum applications.Crop Production/Industries,

Pond biodiversity and habitat loss in the UK

Ponds are common landscape features but have been poorly studied compared to other freshwater habitats in the UK, despite their high frequency of occurrence. In the last century, many ponds have been lost and those that remain face increasing pressure due to agricultural land drainage, pollution and urban development. However, ponds provide important habitats for diverse floral and faunal communities including a number of rare taxa of conservation interest. This paper examines the biodiversity and wider environmental value of ponds with particular reference to the aquatic invertebrate and amphibian communities they support, and the adverse impact of anthropogenic activity on their aquatic habitats

Similarity in Cigarette Smoking Attracts: A Prospective Study of Romantic Partner Selection by Own Smoking, Smoker Prototype, and Perceived Approval

The current research employs a multi-wave longitudinal design to examine how young adults\u27 own smoking, smoker prototypes, and perceived partner approval of smoking are associated with selection of romantic partners over time. Results indicate that participants who smoke and have a more positive prototype of the typical smoker are more likely to initiate a romantic relationship with someone who smokes and who has greater perceived approval for smoking. The findings suggest the importance of examining romantic partner factors associated with young adult smoking and suggest some important aspects of selection effects in terms of the target of selection (romantic partners), what is selected for (partner smoking and approval), and key participant variables that contribute to selection (participant\u27s own smoking and smoker prototype)

Temperature dependent high speed dynamics of terahertz quantum cascade lasers

Terahertz frequency quantum cascade lasers offer a potentially vast number of new applications. To better understand and apply these lasers, a device-specific modeling method was developed that realistically predicts optical output power under changing current drive and chip temperature. Model parameters are deduced from the self-consistent solution of a full set of rate equations, obtained from energy-balance Schro ̈dinger-Poisson scattering transport calculations. The model is thus derived from first principles, based on the device structure, and is therefore not a generic or phenomenological model that merely imitates expected device behavior. By fitting polynomials to data arrays representing the rate equation parameters, we are able to significantly condense the model, improving memory usage and computational efficiency

Urinary Metabolites of Polycyclic aromatic Hydrocarbons in Firefighters: a Systematic Review and Meta-Analysis

Firefighters are intermittently exposed to complex, mixed pollutants in random settings. Of those pollutants, PAHs (polycyclic aromatic hydrocarbons) are the most commonly studied and best understood. PAH exposure can occur via multiple routes; therefore, the levels of hydroxylated metabolites of PAHs in urine have been used as a biomonitoring tool for risk assessment. We performed a systematic review and meta-analysis of the literature to estimate the levels of urinary hydroxylated PAH (OHPAH) among firefighters, determine risk attributions, and, finally, evaluate the scope of preventive efforts and their utility as diagnostic tools. The meta-regression confirmed increases in OHPAH concentrations after fire activities by up to 1.71-times (p-values

Meteorological drivers and mortality associated with O3 and PM2.5 air pollution episodes in the UK in 2006

In this study we examine the meteorological drivers resulting in concurrent high levels of ozone (O3) and particulate matter smaller than 2.5 andmu;m in diameter (PM2.5) during two five-day air pollution episodes in 2006 (1st - 5th July and 18th andndash; 22nd July) using an air quality model (AQUM) at 12 km horizontal resolution to simulate air pollutant concentrations. The resultant UK health burden associated with short-term exposure to simulated maximum daily 8-h O3andnbsp;(MDA8 O3) and daily mean PM2.5andnbsp;is estimated at the national and regional level. Both episodes were found to be driven by anticyclonic conditions with light easterly and south easterly winds and high temperatures that aided pollution build up in the UK. The estimated total mortality burden associated with short-term exposure to MDA8 O3andnbsp;is similar during the chosen episodes with about 70 daily deaths brought forward (summed across the UK) during the first and second episode, respectively. The estimated health burden associated with short-term exposure to daily mean PM2.5andnbsp;concentrations differs between the first and second episode resulting in about 43 and 36 daily deaths brought forward, respectively. The corresponding percentage of all-cause mortality due to short-term exposure to MDA8 O3andnbsp;and daily mean PM2.5during these two episodes and across the UK regions, ranges from 3.4% to 5.2% and from 1.6% to 3.9%, respectively. The attributable percentage of all-cause mortality differs between the regions depending on the pollution levels in each episode, but the overall estimated health burdens are highest in regions with higher population totals. We estimate that during these episodes the short-term exposure to MDA8 O3and daily mean PM2.5andnbsp;is between 36-38% and 39andndash;56% higher, respectively, than if the pollution levels represented typical seasonal-mean concentrations. This highlights the potential of air pollution episodes to have substantial short-term impacts on public health.</p

Future air pollution related health burdens associated with RCP emission changes in the UK

Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways (RCPs) are used to simulate future ozone (O3), nitrogen dioxide (NO2), and fine particulate matter (PM2.5) in the United Kingdom (UK) for the 2050s relative to the 2000s with an air quality model (AQUM) at a 12 km horizontal resolution. The present-day and future attributable fractions (AF) of mortality associated with long-term exposure to annual mean O3, NO2 and PM2.5 have accordingly been estimated for the first time for regions across England, Scotland and Wales. Across the three RCPs (RCP2.6, RCP6.0 and RCP8.5), simulated annual mean of the daily maximum 8-hr mean (MDA8) O3 concentrations increase compared to present-day, likely due to decreases in NOx (nitrogen oxides) emissions, leading to less titration of O3 by NO. Annual mean NO2 and PM2.5 concentrations decrease under all RCPs for the 2050s, mostly driven by decreases in NOx and sulphur dioxide (SO2) emissions, respectively. The AF of mortality associated with long-term exposure to annual mean MDA8 O3 is estimated to increase in the future across all the regions and for all RCPs. Reductions in NO2 and PM2.5 concentrations lead to reductions in the AF estimated for future periods under all RCPs, for both pollutants. Total mortality burdens are also highly sensitive to future population projections. Accounting for population projections exacerbates differences in total UK-wide MDA8 O3-health burdens between present-day and future by up to a factor of ~3 but diminishes differences in NO2-health burdens. For PM2.5, accounting for future population projections results in additional UK-wide deaths brought forward compared to present-day under RCP2.6 and RCP6.0, even though the simulated PM2.5 concentrations for the 2050s are estimated to decrease. Thus, these results highlight the sensitivity of future health burdens in the UK to future trends in atmospheric emissions over the UK as well as future population projections

A QCL model with integrated thermal and stark rollover mechanisms

There is a need for a model that accurately describes dynamics of a bound-to-continuum terahertz quantum cascade laser over its full range of operating temperatures and bias conditions. In this paper we propose a compact model which, through the inclusion of thermal and Stark effects, accurately reproduces the light-current characteristics of an exemplar bound-to-continuum terahertz quantum cascade laser. Through this model, we investigate the dynamics of this laser with a view to applications in high-speed free space communications