Recovery from job stress: The stressor‐detachment model as an integrative framework

This paper reviews empirical evidence on psychological detachment from work during nonwork time. Psychological detachment as a core recovery experience refers to refraining from job‐related activities and thoughts during nonwork time; it implies to mentally disengage from one's job while being away from work. Using the stressor‐detachment model as an organizing framework, we describe findings from between‐person and within‐person studies, relying on cross‐sectional, longitudinal, and daily‐diary designs. Overall, research shows that job stressors, particularly workload, predict low levels of psychological detachment. A lack of detachment in turn predicts high strain levels and poor individual well‐being (e.g., burnout and lower life satisfaction). Psychological detachment seems to be both a mediator and a moderator in the relationship between job stressors on the one hand and strain and poor well‐being on the other hand. We propose possible extensions of the stressor‐detachment model by suggesting moderator variables grounded in the transactional stress model. We further discuss avenues for future research and offer practical implications. Copyright © 2014 John Wiley & Sons, Ltd.     

Are older workers more active copers? Longitudinal effects of age‐contingent coping on strain at work

This study addresses coping processes as explanation of age‐related differences in strain experience. Based on the life‐span theory of control, we posit that older workers employ more active problem‐focused and more active emotion‐focused coping strategies than younger workers, which should mediate age effects on strain at work. The correlation between age and passive avoidance coping, in contrast, is expected to be qualified by external resources such as job control. Hypotheses were tested in a two‐wave panel study (8 months lag) with 634 workers (age range 16–65 years). Job demands were considered as control variables. As predicted, older as compared with younger workers reported more active problem‐focused coping, which mediated age differences on strain in the longitudinal analysis. No mediation was found for active emotion‐focused coping. Moreover, age‐contingent effects of passive avoidance coping were moderated by job control. When job control was low, younger as compared with older workers reported more avoidance coping, which in turn decreased strain in the longitudinal analysis. Finally, reverse longitudinal effects of age‐contingent strain on active problem‐focused and active emotion‐focused coping provide initial evidence for age‐contingent resource spirals. Together, the results reveal specific strengths of older workers for stress management at work. Copyright © 2015 John Wiley & Sons, Ltd.     

A Level‐of‐Service Concept for Planning Future Water Supply Projects under Probabilistic Demand and Supply Framework

One of the most challenging tasks of water supply utilities is planning the timing and quantity of new water supply sources as demand for water consumption grows. Many water supply utilities target on meeting 100% of their customers' needs based on scenario‐based deterministic demand projections numbers even though there are uncertainties in both supply and demand values. This may result in under or overly conservative approach in assessing future needs. In this article, a level‐of‐service concept is introduced to capture a utility's willingness to accept a given level of risk, plan for it, and invoke a management strategy during extreme events than build a facility to accommodate those in planning for new water supply sources. Accounting for uncertainties in both supply and demand help quantify reliability by achieving a prescribed level of service. The major benefit of such an approach for planning future water supply is that it allows policy makers to evaluate the use of adaptive water management strategies and develop supply in an incremental fashion as demand warrants it. For example, if a given level of service cannot be reliably met with the existing system at a future time t, an incremental water supply project would come online to bring the required reliability level up but no more.     

A Review of the United States' Past and Projected Water Use

Good information and data on water demands are needed to perform good analyses, yet collecting and compiling spatially and temporally consistent water demand data are challenges. The objective of our work was to understand the limitations associated with water‐use estimates and projections. We performed a comprehensive literature review of national and regional United States (U.S.) water‐use estimates and projections. We explored trends in past regional projections of freshwater withdrawals and compared these values to regional estimates of freshwater withdrawals made by the U.S. Geological Survey. Our results suggest a suite of limitations exist that have the potential for influencing analyses aiming to extract explanatory variables from the data or using the data to make projections and forecasts. As we explored regional projections, we paid special attention to the two largest water demand‐side sectors — thermoelectric energy and irrigation — and found thermoelectric projections are more spread out than irrigation projections. All data related to water use have limitations, and there is no alternative to making the best use that we can of the available data; our article provides a comprehensive review of these limitations so that water managers can be more informed.     

Two‐Stage Ditch Floodplains Enhance N‐Removal Capacity and Reduce Turbidity and Dissolved P in Agricultural Streams

Two‐stage ditches represent an emerging management strategy in artificially drained agricultural landscapes that mimics natural floodplains and has the potential to improve water quality. We assessed the potential for the two‐stage ditch to reduce sediment and nutrient export by measuring water column turbidity, nitrate (NO₃^?), ammonium (NH₄⁺), and soluble reactive phosphorus (SRP) concentrations, and denitrification rates. During 2009‐2010, we compared reaches with two‐stage floodplains to upstream reaches with conventional trapezoid design in six agricultural streams. At base flow, these short two‐stage reaches (<600 m) reduced SRP concentrations by 3‐53%, but did not significantly reduce NO₃^? concentrations due to very high NO₃^? loads. The two‐stage also decreased turbidity by 15‐82%, suggesting reduced suspended sediment export during floodplain inundation. Reach‐scale N‐removal increased 3‐24 fold during inundation due to increased bioreactive surface area with high floodplain denitrification rates. Inundation frequency varied with bench height, with lower benches being flooded more frequently, resulting in higher annual N‐removal. We also found both soil organic matter and denitrification rates were higher on older floodplains. Finally, influence of the two‐stage varied among streams and years due to variation in stream discharge, nutrient loads, and denitrification rates, which should be considered during implementation to optimize potential water quality benefits.     

The use of environmental DNA in invasive species surveillance of the Great Lakes commercial bait trade

Over 180 non‐native species have been introduced in the Laurentian Great Lakes region, many posing threats to native species and ecosystem functioning. One potential pathway for introductions is the commercial bait trade; unknowing or unconcerned anglers commonly release unused bait into aquatic systems. Previous surveillance efforts of this pathway relied on visual inspection of bait stocks in retail shops, which can be time and cost prohibitive and requires a trained individual that can rapidly and accurately identify cryptic species. Environmental DNA (eDNA) surveillance, a molecular tool that has been used for surveillance in aquatic environments, can be used to efficiently detect species at low abundances. We collected and analyzed 576 eDNA samples from 525 retail bait shops throughout the Laurentian Great Lake states. We used eDNA techniques to screen samples for multiple aquatic invasive species (AIS) that could be transported in the bait trade, including bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix), round goby (Neogobius melanostomus), tubenose goby (Proterorhinus marmoratus), Eurasian rudd (Scardinius erythrophthalmus), and goldfish (Carassius auratus). Twenty‐seven samples were positive for at least one target species (4.7% of samples), and all target species were found at least once, except bighead carp. Despite current regulations, the bait trade remains a potential pathway for invasive species introductions in the Great Lakes region. Alterations to existing management strategies regarding the collection, transportation, and use of live bait are warranted, including new and updated regulations, to prevent future introductions of invasive species in the Great Lakes via the bait trade. El Uso del ADN Ambiental en la Vigilancia de Especies Invasoras del Mercado de Carnada Comercial de los Grandes Lagos     

Reducing Nitrogen Export from the Corn Belt to the Gulf of Mexico: Agricultural Strategies for Remediating Hypoxia

SPAtially Referenced Regression on Watershed models developed for the Upper Midwest were used to help evaluate the nitrogen‐load reductions likely to be achieved by a variety of agricultural conservation practices in the Upper Mississippi‐Ohio River Basin (UMORB) and to compare these reductions to the 45% nitrogen‐load reduction proposed to remediate hypoxia in the Gulf of Mexico (GoM). Our results indicate that nitrogen‐management practices (improved fertilizer management and cover crops) fall short of achieving this goal, even if adopted on all cropland in the region. The goal of a 45% decrease in loads to the GoM can only be achieved through the coupling of nitrogen‐management practices with innovative nitrogen‐removal practices such as tile‐drainage treatment wetlands, drainage–ditch enhancements, stream‐channel restoration, and floodplain reconnection. Combining nitrogen‐management practices with nitrogen‐removal practices can dramatically reduce nutrient export from agricultural landscapes while minimizing impacts to agricultural production. With this approach, it may be possible to meet the 45% nutrient reduction goal while converting less than 1% of cropland in the UMORB to nitrogen‐removal practices. Conservationists, policy makers, and agricultural producers seeking a workable strategy to reduce nitrogen export from the Corn Belt will need to consider a combination of nitrogen‐management practices at the field scale and diverse nitrogen‐removal practices at the landscape scale.     

Introducing a Low‐Head Dam Fatality Database and Internet Information Portal

Low‐head dams can cause dangerous currents near the downstream face of the structure. Fatalities at low‐head dams with such currents, often referred to as “drowning machines,” are poorly documented. This technical note presents a new database of fatalities at low‐head dams in the United States together with an interactive map and web‐based user interface. The primary purpose of the system is to raise awareness, generate interest, and educate the general public and decision makers regarding these dangerous structures and the need for remediation. The database was designed as a normalized relational database of event dates, severity, location, reporter, and other circumstances. The open‐access user interface allows the general public to browse fatal incidents by geographic location and to read incident circumstances. The system allows submission of new contributions from users including all metadata needed to characterize the incident. The database is structured to include documentation verifying each entry. The site can be viewed at http://dams.byu.edu/ .     

The solution phase complexing of atrazine by fulvic acid: Equilibria at 25°c

Abstract

The solution phase complexing equilibria of atrazine by fulvic acid at 25°C±1.° have been investigated over the pH range of 1.3 to 6.0. Experiments with 0.1MKC1 and chelated Cu(II) are compared with those without metal ions. The use of a fulvic acid having calibrated acidic and Cu(II) chelation properties has made it possible to obtain stoicheometricly “exact”; chemical information. This is correlated with previous hydrolysis kinetics work. It is concluded that atrazine is hydrogen bonded in a labile equilibrium, to an identifiable set of protonated carboxyl groups, which act as Brönsted acid catalysts for hydrolysis. 0.1M KC1 changes (1‐α_A), the degree of protonation of the carboxyl groups, without otherwise affecting the atrazine complexing. Cu(II) chelation both reduces and weakens the complexing through a combination of carboxyl group blocking, and fulvic acid aggregation. Simple equations are presented for predictive calculations.     

Effect of adjuvants on rainfastness and herbicidal activity of glyphosate deposits on trembling aspen foliage

Abstract

Radiolabelled end‐use mixtures of glyphosate with and without a cationic surfactant (Ethomeen® T/25) and an organosilicone surfactant (Silwet® L‐77) were applied onto trembling aspen (Populus tremuloids Michx.) leaves at the rate of 1.0 kg of AE (acid equivalent) in 35 L/ha area of foliage. A 5‐mm rainfall with an intensity of 10 mm/h was applied at intervals of 0.5, 8, 24, 36, 48, 72, and 96 h after treatment. Glyphosate washoff was determined by liquid scintillation counting of radioactivity in the rain‐washing. At 36 h post‐treatment, both the adjuvants significantly reduced glyphosate washoff (Ethomeen by 69.6% and Silwet by 59.7%) from foliage, compared to the washoff (82.6%) when Vision alone was applied without the adjuvants. Results on the rate of plant growth indicated that with a rain‐free period of 8 h or more, the growth of most seedlings was stunted within 1 or 2 d. Percentage of foliar browning 20 d after treatment with rain‐free period of 8 to 48 h ranged from 8 to 80% for Vision alone, 75 to 100% for Vision with Ethomeen, and 85 to 100% for Vision with Silwet, respectively. Physical properties of the end‐use mixtures were measured with and without the two adjuvants to examine droplet spreading and drying rates in relation glyphosate rainfastness. The Silwet adjuvant lowered the surface tension of the end‐use mixture, but Ethomeen did not. Droplets containing Silwet were spread more than those containing Ethomeen. However, the greater area of contact caused by Silwet did not contribute to a significant increase in the translocation rate of glyphosate into untreated parts of the seedlings, and showed no relationship with rainfastness of glyphosate deposits on trembling aspen.