The Inhibition of Photochemical Smog

Additional inhibitors for the conversion of NO to NO₂ in C3H6—NO—0₂ irradiated mixtures have been tested at 25°C. These mixtures initially contained 16 mTorr C₃H₆, 8 mTorr NO, 0.012 mTorr NO₂, additive, and enough O₂ to bring the total pressure to 100 Torr. The NO₂ pressure was monitored photometrically. In the absence of additive, the NO₂ pressure first increases with irradiation time reaching a maximum conversion at about 15 minutes. As the irradiation time increases beyond 15 min, the NO₂ pressure drops. Before adding the inhibitors, runs were done with 10 Torr of CO added, and in these runs the conversion was speeded so that the maximum in NO₂ pressure occurred at 10 min. This enhancement in conversion rate is considered to be diagnostic for the presence of HO radicals. Next 10-min irradiations were done with various amounts of hexafluorobenzene (C₆F₆), nitrobenzene (C₆H₅NO₂), or naphtha lene (C₁₀H₈) added. The NO₂ pressure was reduced to one-half its value in the absence of inhibitor with 270 mTorr C₆F₆’, 220 mTorr C₆H₅N0₂, or 4 mTorr C₁₀Hg. The C₁₀H₈ is a very efficient inhibitor, but additions of up to 1 8.5 mTorr C₁₀H₈ did not reduce the N0₂ pressure to zero. Studies of the percent conversion of NO to NO₂ vs. irradiation time were done with either 4.2 mTorr C₁₀H₈ or 40 mTorr 2,6-di-ferf-butyl-4-methylphenol (Ph) added. In the former case the peak conversion was delayed from 15 to 22 min, while in the latter case no delay occurred. However, with the Ph added, there appeared to be some reduction in the maximum value of percent conversion.     

Asian Urban Environment and Climate Change: Preface

The Asian Network on Climate Science and Technology (www.ancst.org), in collaboration with Tsinghua University, held a conference on environmental and climate science, air pollution, urban planning and transportation in July 2015, with over 40 Asian experts participating and presentation. This was followed by a meeting with local government and community experts on the practical conclusions of the conference. Of the papers presented at the conference a selection are included in this special issue of Journal of Environmental Science, which also reflects the conclusions of the Paris Climate meeting in Dec 2015, when the major nations of the world agreed about the compelling need to reduce the upward trend of adverse impacts associated with global climate change. Now is the time for urban areas to work out the serious consequences for their populations, but also how they should work together to take action to reduce global warming to benefit their own communities and also the whole planet!     

A new fossil thryonomyid from the Late Miocene of the United Arab Emirates and the origin of African cane rats

Cane rats (Thryonomyidae) are represented today by two species inhabiting sub-Saharan Africa. Their fossil record is predominately African, but includes several Miocene species from Arabia and continental Asia that represent dispersal events from Africa. For example, Paraulacodus indicus, known from the Miocene of Pakistan, is closely related to living Thryonomys. Here we describe a new thryonomyid, Protohummus dango, gen. et sp. nov., from the late Miocene Baynunah Formation of the United Arab Emirates. The new thryonomyid is less derived than “Thryonomys” asakomae from the latest Miocene of Ethiopia and clarifies the origin of crown Thryonomys and the evolutionary transition from Paraulacodus. A phylogenetic analysis shows Protohummus dango to be morphologically intermediate between Paraulacodus spp. and extinct and living Thryonomys spp. The morphological grade and phylogenetic position of Protohummus dango further supports previous biochronological estimates of the age of the Baynunah Formation (ca. 6–8 Ma).     

Acoustic underwater signals with a probable function during competitive feeding in a tadpole

Acoustic communication is widespread among adult stages of terrestrial animals and fish and has also been observed in insect larvae. We report underwater acoustic communication in the larvae of a frog, Gephyromantis azzurrae, from Isalo, a sandstone massif in western Madagascar. According to our field data, these tadpoles live in streams and prefer habitats characterized by comparatively low temperatures, shallow water depth, and a relatively fast current. Feeding experiments indicated that the tadpoles are carnivorous and macrophagous. They consumed insect larvae and, to a lesser extent, small shrimps, and conspecific as well as heterospecific tadpoles. Calls of these tadpoles consisted either of single click notes or of irregular series of various clicks. Some complex calls have a pulsed structure with three to nine indistinct energy pulses. Production of the pulses coincided with rapid closure of the jaw sheaths and often with an upward movement of the body. Calls were emitted while attacking prey and occurred significantly more often when attacking conspecifics. Tadpoles that had not been fed for some time emitted sounds more frequently than those that had been regularly fed. The spectral frequency of the calls differed in tadpole groups of different size and was higher in groups of smaller tadpoles, suggesting that spectral frequency carries some information about tadpole size which might be important during competitive feeding to assess size and strength of competitors. This report differs from those for the larvae of South American horned frogs, Ceratophrys ornata. These are the only other tadpoles for which sound production has reliably been reported but the calls of Ceratophrys tadpoles occur mainly in a defensive context.     

Colonized beads as inoculum for marine biodegradability assessment: Application to Linear Alkylbenzene Sulfonate

An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 μg/L). Thereafter, such colonized beads were added as inoculum in different test systems. [¹⁴C]-LAS (5–100 μg/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (10⁹ bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to < 1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL. This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 mL).     

Towards a multi‐foci approach to workplace aggression: A meta‐analytic review of outcomes from different perpetrators

Using meta‐analysis, we compare three attitudinal outcomes (i.e., job satisfaction, affective commitment, and turnover intent), three behavioral outcomes (i.e., interpersonal deviance, organizational deviance, and work performance), and four health‐related outcomes (i.e., general health, depression, emotional exhaustion, and physical well being) of workplace aggression from three different sources: Supervisors, co‐workers, and outsiders. Results from 66 samples show that supervisor aggression has the strongest adverse effects across the attitudinal and behavioral outcomes. Co‐worker aggression had stronger effects than outsider aggression on the attitudinal and behavioral outcomes, whereas there was no significant difference between supervisor, co‐worker, and outsider aggression for the majority of the health‐related outcomes. These results have implications for how workplace aggression is conceptualized and measured, and we propose new research questions that emphasize a multi‐foci approach. Copyright © 2009 John Wiley & Sons, Ltd.     

WRF-Chem simulation of East Asian air quality: Sensitivity to temporal and vertical emissions distributions

This study develops fine temporal (seasonal, day-of-week, diurnal) and vertical allocations of anthropogenic emissions for the TRACE-P inventory and evaluates their impacts on the East Asian air quality prediction using WRF-Chem simulations in July 2001 at 30-km grid spacing against available surface measurements from EANET and NEMCC. For NO₂ and SO₂, the diurnal and vertical redistributions of emissions play essential roles, while the day-of-week variation is less important. When all incorporated, WRF-Chem best simulates observations of surface NO₂ and SO₂ concentrations, while using the default emissions produces the worst result. The sensitivity is especially large over major cities and industrial areas, where surface NO₂ and SO₂ concentrations are reduced by respectively 3–7 and 6–12 ppbv when using the scaled emissions. The incorporation of all the three redistributions of emissions simulates surface O₃ concentrations higher by 4–8 ppbv at night and 2–4 ppbv in daytime over broad areas of northern, eastern and central China. To this sensitivity, the diurnal redistribution contributes more than the other two.     

Chicken manure enhanced yield and quality of field-grown kale and collard greens

Organic matter and nutrients in municipal sewage sludge (SS) and chicken manure (CM) could be recycled and used for land farming to enhance fertility and physical properties of soils. Three soil management practices were used at Kentucky State University Research Farm, Franklin County, to study the impact of soil amendments on kale (Brassica oleracea cv. Winterbar) and collard (Brassica oleracea cv. Top Bunch) yields and quality. The three soil management practices were: (i) SS mixed with native soil at 15 t acre^?1, (ii) CM mixed with native soil at 15 t acre^?1, and (iii) no-mulch (NM) native soil for comparison purposes. At harvest, collard and kale green plants were graded according to USDA standards. Plants grown in CM and SS amended soil produced the greatest number of U.S. No. 1 grade of collard and kale greens compared to NM native soil. Across all treatments, concentrations of ascorbic acid and phenols were generally greater in kale than in collards. Overall, CM and SS enhanced total phenols and ascorbic acid contents of kale and collard compared to NM native soil. We investigated the chemical and physical properties of each of the three soil treatments that might explain variability among treatments and the impact of soil amendments on yield, phenols, and ascorbic acid contents of kale and collard green grown under this practice.     

A Model for Gaseous Pollutant Sorption by Leaves

A model simulating pollutant exchange with isolated leaves that integrates factors which have been found to be important in regulating pollutant uptake by leaves is presented. The model is patterned after an electrical analogue simulator and was designed to emphasize the effects of pollutant and leaf properties on the process. The article discusses the relative significance of factors affecting gas transfer, sorption of pollutants by leaf surfaces, and pollutant solubility and fate on the uptake process. Data is presented showing uptake of ozone by exposed mesophyll and several epidermal surfaces chosen for their different surface characteristics. The model was used to derive a mathematical expression for the exchange process which was rearranged to define internal (average) pollutant solute concentration in terms of external concentration, leaf and boundary layer diffusion resistance, surface sorption and pollutant solubility. The importance of estimating internal solute concentration is discussed.