California Statewide Assessment of the Effects of Ozone on Crop Productivity

Six properties appear desirable for any set of ozone attainment criteria: (1) sufficient stringency to protect public health, (2) simplicity and understandability, (3) sensitivity to real changes in air quality, (4) stability against meteorological fluctuations, (5) use of as much data as possible, and (6) equivalence between the stringency the criteria appear to mandate, and what they actually mandate. We consider how the federal attainment criteria might be improved with respect to Properties 4 through 6 while being equally strong on 1 through 3. Whether the federal standard meets Property 1 has been the subject of debate, but our analysis would apply also to a modified standard. We show that there are subtleties in how improvements might be made. In particular, basing the attainment status on a statistic with low variance may not lead to a more stable criterion, and although it is easy to find a criterion that makes it hard for a district with bad air to reach attainment, or a district with good air to get out of attainment, it is hard to find a criterion that does both. This suggests using different criteria for districts that are out of attainment from districts that are in attainment. Initially the burden of proof would be on the district to prove that its air is of attainment quality. However, once the district has achieved attainment the burden of proof would shift; the district would remain in attainment unless there was strong evidence to the contrary. An evaluation of a set of criteria based on this idea showed improvements over the federal criteria with respect to the last three desirable properties-stability, use of data, and equivalent stringency-with some sacrifice in simplicity and sensitivity.     

DYNAMIC RESPONSE OF AQUIFER SYSTEMS TO LOCALIZED RECHARGE1

ABSTRACT. The response of stream-unconfined aquifer systems to localized recharge is investigated by means of a two-dimensional finite element model. A variational approach is used in conjunction with the finite element method to solve the ground water flow equation. Linear approximated triangular elements are used to calculate the hydraulic head distribution in the flow region. The Crank-Nicholson centered scheme of numerical integration is employed to approximate the time derivative in the flow equation. A computer program is developed to calculate the hydraulic head distribution in the flow region. Solutions provided by the finite element model should prove useful in the evaluation of quantitative and qualitative changes in aquifer systems due to natural or artificial recharge. In addition, they should prove useful in the study of irrigation and drainage problems.     

Composting of vinasse and cotton gin waste by using two different systems

Two composts were obtained by co-composting of a concentrated depotassified beet vinasse and cotton gin waste using two different aeration systems: static aerated pile (forced aeration provided by a blower whom operated in the positive mode) and windrow (turned pile). The composting mixtures were cotton gin trash (55%) and vinasse (45%) (dry weight). In static pile, the total amount of vinasse was added at the beginning of the process whereas, in windrow two additions of vinasse were performed. Differences in temperature changes between both composting systems were found: a faster increase of temperature in the windrow (54 °C at 7 days) than in the static pile (45 °C at 21 days) was observed. Probably in the static pile system, the compaction of the substrates made difficult the correct distribution of the air inside the pile. Moreover, after the second addition of vinasse a new thermophilic phase was started in windrow. The different aeration systems and the way of addition of vinasse could cause differences in organic matter (OM) degradation and in weight (22.6% for the static pile and 26.7% for the windrow) and gas losses during the process. Nevertheless, the composts obtained by the two systems had a high fertilizer value (25.1 g kg⁻¹ N; 3.2 g kg⁻¹ P₂O₅; 21.4 g kg⁻¹ K₂O; C/N8) for compost obtained in static pile and (16.2 g kg⁻¹ N; 3.4 g kg⁻¹ P₂O₅; 16.1 g kg⁻¹ K₂O; C/N 12) for compost obtained in the windrow). A high degree of stability was reached in the final composts. Composting of vinasse with cotton gin waste serves two objectives, disposal of wastes and recycling of waste components.     

Selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies

Selective intrauterine growth restriction (sIUGR) occurs in 10 to 15% of monochorionic (MC) twins, and it is associated with a substantial increase in perinatal mortality and morbidity. Clinical evolution is largely influenced by the existence of intertwin placental anastomoses: pregnancies with similar degrees of fetal weight discordance are associated with remarkable differences in clinical behavior and outcome. We have proposed a classification of sIUGR into three types according to umbilical artery (UA) Doppler findings (I-normal, II-absent/reverse end-diastolic flow, III-intermittent absent/reverse end-diastolic flow), which correlates with distinct clinical behavior, placental features and may assist in counseling and management. In terms of prognosis, sIUGR can roughly be divided in two groups: type I cases, with a fairly good outcome, and types II and III, with a substantial risk for a poor outcome. Management of types II and III may consist in expectant management until deterioration of the IUGR fetus is observed, with the option of cord occlusion if this occurs before viability. Alternatively, active management can be considered electively, including cord occlusion or laser coagulation. Both therapies seem to increase the chances of intact survival of the larger fetus, while they entail, or increase the chances of, intrauterine demise of the IUGR fetus. Copyright © 2010 John Wiley & Sons, Ltd.     

Exploratory analysis of Spanish energetic mining accidents

Using data on work accidents and annual mining statistics, the paper studies work-related accidents in the Spanish energetic mining sector in 1999-2008. The following 3 parameters are considered: age, experience and size of the mine (in number of workers) where the accident took place. The main objective of this paper is to show the relationship between different accident indicators: risk index (as an expression of the incidence), average duration index for the age and size of the mine variables (as a measure of the seriousness of an accident), and the gravity index for the various sizes of mines (which measures the seriousness of an accident, too). The conclusions of this study could be useful to develop suitable prevention policies that would contribute towards a decrease in work-related accidents in the Spanish energetic mining industry.     

Current status and future restoration of coastal dune systems on the Catalan shoreline (Spain,NW Mediterranean Sea)

Coastal dunes are an essential part of beach-dune systems. Dunes systems have their own intrinsic values and provide a range of goods and services, including the protection of tangible goods located on the shoreline affected by waves, storms, and sea erosion. Dunes also act as repositories of biodiversity that have their exclusive habitat in dune communities, and the aesthetic value of dune landscapes derived from unique plant communities and landforms is also of great importance. Nevertheless, dune systems on developed coasts suffered a drastic decline in geomorphological and ecological quality throughout the last century. Catalonia (Spain, NW Mediterranean Sea) is no exception, and the coastal dune systems which were present in the early 20th century have now disappeared due to urbanization. The regeneration of dune systems is of crucial importance in this context. The aim of this study is to assess the current status of dune systems in Catalonia in order to determine their future prospects based on beach characteristics, those beaches likely to host dunes being determined according to their width and sediment type. The results of our study show that nowadays most dune systems in Catalonia are not developed due to human pressure on the beaches. Only those beaches located in the natural protected areas in Roses Bay, Baix Ter Bay, the Llobregat Delta, and especially the Ebro Delta, have the right characteristics to host well-developed dune systems. That said, 30% of sandy beaches in Catalonia have a width of over 35 metres; wide enough to host well-developed dune systems if appropriate integrated beach management is applied. The methodology used in this research also provide a tool to assess which are the beaches that can host dunes on other developed shores in the Mediterranean area.     

Trace elements in wild grasses: a phytoavailability study on a remediated field

There have been significant efforts to establish a widely usable method for the prediction of trace element bioavailability in soil. In this work, we used extraction with 0.01 M CaCl₂ and 0.05 M ethylenediaminetetraacetic acid (EDTA) to estimate bioavailable concentrations of As, Cd, Cu, Pb, and Zn in a soil moderately contaminated with trace elements 1 and 2 years after the application of three amendments. The experiment took place in a field plot of a soil affected by the toxic spill of the Aznalcóllar mine. Four treatments were established: three with amendments (biosolid compost, sugar beet lime, and a combination of leonardite plus sugar beet lime) and a control without amendment. Trace element concentrations of two representative species in each year (Lamarckia aurea and Poa annua in 2004 and Lamarckia aurea and Bromus rubens in 2005) were analyzed. The results showed a positive effect of the amendments both on soil and vegetation. Trace element concentrations in plants growing in the amended subplots were lower than those in plants from nonamended subplots. As a rule, concentrations of CaCl₂-soluble Cd, Cu, and Zn in soil were positively correlated with trace elements in plants, whereas EDTA extraction was scarcely correlated with plant concentration. For species of grasses, especially L. aurea, CaCl₂ seems to be a more suitable extractant to predict trace element bioavailability in this contaminated soil.