Plant response to utility right of way construction in the Mojave Desert

Disturbance of flora from utility construction tends to generate new plant growth. This growth changes productivity, diversity, and stability. Although the enhancement of vegetation may balance out the biomass destroyed by the original disturbance, it often adversely affects the quality of the vegetation. Percentage composition of the dominant long-lived perennials combined with quantitative measures are used to assess longterm effects of utility corridor construction. Differential effects of enhancement of vegetation are found along road edges, enhancement under wires of powerlines, and over trenches dug for pipelines. Areas under powerline pylons seem to receive the greatest damage and also show the most variable recovery of vegetation. Significant recovery rates are noticeable where the time span between year of construction has allowed for considerable regrowth of the older corridor. Recovery rates depend on soil type, landform, and other physical features of the disturbed sites. Drastic disturbance in one area or transect site may impede vegetation recovery, whereas slight disturbance might enhance vegetation in another, tending to offset the effect of the drastic disturbance. Disturbed areas and control areas may appear to have similar vegetation covers, biomasses, and densities, but these similarities often vanish when one examines qualitative aspects, such as proportion of long-lived species and presence of characteristic dominants.     

SCALE PROBLEMS IN INTERDISCIPLINARY WATER RESOURCES INVESTIGATION1

ABSTRACT The problems encountered in estimating scale parameters in interdisciplinary watershed research are discussed. Meteorology, hydrology, geology and water quality are discussed with respect to their individual strengths and weaknesses when applied to different scale problems. Areas where incompatibilities exist are pointed out and suggestions are made for effecting compromise. A watershed scale of roughly a hundred acres may be the scale at which all disciplines can effect optimum interaction.     

The Information Content of a Scalar Plume – A Plume Tracing Perspective

The ability of many animals and insects to track a plume to its source is a particularly impressive feat when the fluid dynamics is considered. Inspired by this observation this research seeks to identify the information in a passive scalar plume suitable for developing robust and efficient plume tracing algorithms. The subject of this study is a scalar plume emanating from a point source in a turbulent boundary layer which has been modeled in a laboratory facility built specifically for this purpose. A coupled PIV-LIF technique is used to measure the velocity and scalar field in a time resolved fashion. This data set is analyzed and the convergence rates of five single-point statistics, suitable as kernels of plume tracing algorithms, are investigated. The experimental data shows that the scalar fluctuations over long downstream distances from the source are characterized by filamentary structures that lead to relatively slow convergence rates for any statistic that is based on mean concentrations. The scalar intermittency, however, converges rapidly toward its true value, in fact converging to a testable hypothesis for source location direction faster than the time scale of the larger scale plume meander.     

Comparison of measurement methods for the characterization of the black carbon emissions from a T63 turboshaft engine burning conventional and Fischer-Tropsch fuels

Emission measurements of black carbon (BC) mass were conducted on a T63 turboshaft engine, operated at idle and cruise power with conventional and alternative fuels, using an Artium LII-300 laser-induced incandescence analyzer (LII) and AVL model 483 micro soot sensor (MSS) photoacoustic instrument using the manufacturer’s calibration for both instruments. These measurements were compared with elemental carbon (EC) determined by manual and semicontinuous thermal-optical transmission analyses according to National Institute for Occupational Safety and Health (NIOSH) method 5040 as the reference method. The results indicate that both the LII and MSS instruments show good linear correlation with EC for the two fuels and two engine power conditions evaluated. The LII measurements were observed to be biased high (27–49%) and the MSS measurements were biased low (24–35%) relative to EC. The agreement between the instruments and the reference method was substantially improved by applying a calibration of the instruments against a common BC aerosol source. Test data also suggest that the two instruments show some sensitivity to particle size (or properties related to size), specifically for particles with a geometric mean diameter (GMD) <30 nm. This sensitivity is problematic, since new engines or certain combustion conditions in current engines will produce smaller particles compared with the T63 model tested in this study. Further assessments of instrument performance for particles within this size range are therefore warranted.

Implications: Accurate black carbon emission measurements are needed to certify new and in-production commercial aircraft engines. Both the Artium LII-300 and AVL 483 micro soot sensor are currently approved by the International Civil Aviation Organization for this purpose. This study compares the two instruments against elemental carbon (EC) using NIOSH method 5040 as the reference using a T63 turboshaft engine. The results indicate that both instruments correlate reasonably well with EC, and the correlation substantially improved when applying a calibration against a common aerosol source. Sensitivity to particle size may be an issue for both instruments.     

Trace metal concentration in scalp hair of occupationally exposed autodrivers

The concentrations of Cr, Pb, Zn, Cu, Ni and Cd wereanalyzed by Atomic Absorption Spectrophotometer in thescalp hair of professional male autodrivers who areoccupationally exposed to the vehicular/industrialpollutants in the industrial city of Coimbatore, TamilNadu. The unwashed hair samples when compared with thewashed hair showed a significantly higher levels of Cr,Zn and Pb. The correlation coefficient showed a strongmutual dependence on the scalp hair of the exposedindividuals and no correlation was found among the tracemetals except for Ni–Pb and Ni–Cd. The results ingeneral showed a positive exogenous contribution of allthe analyzed industrial trace metals. The drivers who are occupationally exposed to vehicular/industrial pollution are at risk.     

全球水价上涨

全球水价上涨，而且有时势头很猛。过去五年，城市供水平均涨价幅度为：美国27％、英国32％、澳大利亚45％、南非50％、加拿大58％。在突尼斯，灌溉水10年里涨了4倍。对14国的最新调查结果表明，城市每立方米水的平均价格从美国的66美分到丹麦和国的2．25美元不等。     

Competitive Distortions In An International Emissions Trading Market

The objective of this paper on international greenhouse gasemissions trading is to find the conditions, if any, under which internationaldifferences in domestic permit allocation procedures lead to competitivedistortions.The paper finds that grandfathered firms or sectors do not have a costadvantage over identical auctioned firms or sectors abroad, as long asmarkets are perfectly competitive, because they have to include theopportunity costs of using the permits in the product price. However,grandfathered permits are a capital gift to the firm, inducing a windfallprofit, which implies that a similar firm abroad which has to buy its permitshas a higher cash outflow and hence less financial resources. This aspect ofgrandfathering becomes relevant when considering imperfect competitionor equity.Firstly, it is concluded that competitive distortions may arise underimperfect competition, mainly because the grandfathered firms can outlastthe auctioned firms abroad in a price war. Secondly, it appears thatcompetition (or: the level playing field) is distorted in terms of equity,because the mere process of permit allocation gives the grandfathered firmsa stronger financial position and thus an unfair competitive advantage overtheir auctioned competitors abroad.In legal terms, these findings imply that grandfathering is WTO compatibleif one is only willing to consider efficiency and assume perfect competition.However, grandfathering constitutes an actionable subsidy under WTO lawif one also considers equity or if competition is imperfect, which couldnecessitate some level of international harmonization of domestic permitallocation rules.     

Untersuchung über das „19-Minuten“-Isotop von Molybdän und das daraus entstehende Isotop von Element 43

The Science of Nature -