bluuebunny/crossref_metadata_2025_split huggingface dataset:
Construction of an efficient Escherichia coli cell‐free system for in vitro expression of several kinds of proteins
Authors: Ma Rongrong , Yang Zhong , Huang Lei , Zhu Xiangcheng , Kai Lei , Cai Jin , Wang Xiaoning , Xu Zhinan 
Published: July 2010

AbstractCell‐free protein synthesis systems have offered several advantages over traditional cell‐based expression methods. In this study, the effects of extract preparation and an energy‐regenerating system on protein synthesis were investigated in an Escherichia coli cell‐free system. The results indicated that the expression level of enhanced green fluorescent protein (eGFP) with the S12 extract was higher than that with the S30 extract. Among four adenosine triphosphate‐regenerating sources, the cAMP/CP/CK system (including cAMP, creatine phosphate, and creatine kinase) proved to be the most efficient one to support high‐level expression of eGFP. Further studies showed that this established cell‐free system could be successfully used to produce one model protein (eGFP), two human proteins (AK2 and coenzyme synthase) and two membrane proteins (subunit b of F1F0 adenosine triphosphate synthase and aquaporin Z). This outcome will be helpful to develop the highly efficient cell‐free technology for the production of various proteins with different bio‐origins.
Ozone is mutagenic in salmonella
Authors: Dillon Deborah , Combes Robert , McConville Malcolm , Zeiger Errol 
Published: July 2010

AbstractOzone is a highly reactive gas that has been tested for genotoxicity in a number of systems. Induced genetic damage resulting from ozone treatment may not be readily observed because of the high toxicity of the chemical and difficulties in generating and administering controlled concentrations. The mutagenicity of ozone was investigated in Salmonella typhimurium using a plate test protocol designed for reactive vapours and gases. Ozone, at two to three consecutive doses, induced weak, albeit statistically significant, mutagenic responses in tester strain TA102 with and without Aroclor‐induced rat liver S9 (lowest effective mean concentration of 0.019 ppm; 35 min total exposure). However, dose‐related responses were not always obtained. No mutagenicity was detected in strains TA98, TA100, or TA1535, with or without S9. In strain TA104, ozone induced a weak response only at a single dose with S9; this response was not reproducible. Mutagenicity was dependent on the ozone flow rate and total exposure time, with variations in the optimum dose‐time regimen leading to toxicity or complete inactivity. The data show that ozone is a very weak bacterial mutagen and only when tested under narrowly prescribed, subtoxic dosing conditions.
Ill‐conditioned information matrices, generalized linear models and estimation of the effects of acid rain
Authors: Smith Eric P. , Marx Brian D. 
Published: July 2010

AbstractThe problem of acid rain deposition has generated much interest in the modelling and estimation of the effects of acid rain. Recent studies in the northeastern United States have focused on the question of trends in lake acidity and the effects on aquatic organisms, especially fish. One approach has been to model the presence or absence of fish species as a function of relevant environmental variables. As the number of these explanatory variables may be large, there is concern about redundancies and collinearities. Because the model used is a special case of generalized linear models, standard approaches to assessment and adjustment for collinearity may be misleading. Estimation of parameters in the generalized linear model involve an interative method of solution. The important parameter is the information matrix. Illconditioning of this matrix, as caused by collinearity has severe effects on parameter and variance estimates. To asssess the effects of collinearities, some new diagnostics are presented. Two techniques for estimating parameters in the presence of multicollinearity; the ridge estimator and the principal component method, are extended to the generalized linear model.
Finnish lake acidification survey: Survey design and random selection of lakes
Authors: Forsius Martin , Malin Väinö , Mäkinen Irma , Kämäri Juha , Kortelainen Pirkko , Verta Matti 
Published: July 2010

AbstractA survey of 1,189 lakes was conducted in the fall of 1987 as part of the Finnish Research Project on Acidification (HAPRO). Most of the lakes for the survey (n=987) were randomly selected by a two‐stage cluster sampling from two separate subregions, together covering the whole country. Lakes of sizes 0.01‐10 km2 were included in the statistical sampling of the southern and central regions (Subregion 1). In northern Finland (Subregion 2) only lakes of sizes 0.1‐10 km2 were included. The statistical sampling “frame” in each subregion consisted of the number of lakes in the grid net formed from a series of topographic maps with a scale of 1:50,000 (20X30 km2). The total number of maps was 472 in Subregion 1 and 175 in Subregion 2. In the first sampling stage, 100 maps were selected from Subregion 1 and 25 maps from Subregion 2, using the “probability proportional to size (pps)” method, selection of the maps being weighted by lake density. In the second sampling stage, all of the lakes with a size within the determined size range were numbered and eight lakes chosen by systematic random sampling from each previously selected map. A further 202 mainly head water lakes examined in previous acidification studies were also included. Water samples were taken from the surface layer (1m) of the lakes during fall overturn in 1987. An extensive analytical program was carried out on each lake‐water sample. Major watershed characteristics have been determined from topographic and soil maps. The statistically based survey design allows estimates to be made of the proportion of lakes fulfilling any predetermined criteria and the corresponding variances. The number of acidic (acid neutralizing capacity (ANC) ⩽ 0 μeq L‐1) lakes in Finland was estimated to be 4,900.
Design of a soil sampling study to determine the habitability of the emergency declaration area, Love Canal, New York
Authors: Peterson Bruce , Millard Steven P. , Wood Eric F. , Lettenmaier Dennis P. 
Published: July 2010

AbstractLove Canal is a 6.4 hectare tract, originally an uncompleted power canal, which was used for disposal of industrial chemicals in the 1940's and 1950's. The canal was later filled, and a school and residences were built on the site. Following a highly publicized discovery of contaminant migration from the canal in the 1970's, the school and nearby homes were demolished. Determination of the habitability of about 800 homes evacuated by Presidential order in 1980 in the surrounding Love Canal Emergency Declaration Area (EDA), was a highly visible environmental policy decision. The soil habitability study for the EDA was based on two‐sample comparisons of concentrations of eight trace organic indicators (Love Canal Indicator ChemicalsMdashLCICs) in EDA neighborhoods with selected comparison areas (CAs). The power of the statistical procedure (s) was an explicit criterion in the design of the study on which the habitability decision was based.Monte Carlo experiments were used to evaluate the relative performance of candidate statistical tests. The Monte Carlo simulations led to a recommendation for a pilot study to better identify the statistical characteristics of the soil chemical data. Analysis of the pilot study data, collected in the spring of 1986, suggested 1) that Monte Carlo experiments should be focused on univariate and multivariate Wilcoxon tests, 2) that a log normal mixture distribution provided reasonable fits to the observed data and could be used to evaluate a wide range of alternative hypotheses, and 3) that between‐laboratory variation would have to be explicitly addressed by the statistical test(s) and in experimental design. The test that was finally selected was a generalization of the Wilcoxon rank sum test for blocking by laboratory.The univariate (single chemical) and multivariate (multiple chemical) blocked Wilcoxon tests were applied to all combinations of EDA sampling areas and comparison areas using field data collected in the fall of 1987. For most comparisons and chemicals, the EDA sampling areas were found not to have significantly higher soil LCIC concentrations than the comparison areas. However, a few EDA sampling areas showed consistently higher concentrations for several LCICs. The multivariate test was particularly useful in avoiding the multiple comparison problem with respect to soil chemicals. Based in part on the results of the soil sampling study, the New York State Commissioner of Health, in September 1988, identified EDA neighborhoods that were suitable for rehabitation. Although the decision was made in a policy framework, the specific recommendations were consistent with the results of the statistical analyses.
What can environmetrics offer?
Authors: Jakeman A. J. 
Published: July 2010

AbstractEnvironmetrics is a discipline involving statistical methods in the environmental sciences. It could also be interpreted more broadly to include the development and application of quantitative methods for the treatment of environmental problems. This broader interpretation widens the appeal of The International Environmetrics Societies, allowing it the option to be more transdisciplinary in its activities. The paper demonstrates with a simple example involving rainfall‐runoff event modelling that the development of quantitative methods often involves non‐statistical issues. There is also a plea that TIES considers attracting the interests of social scientists.
A deterministic‐probabilistic approach for groundwater flow in a semiconfined random aquifer
Authors: Satish M. G. , Zhu J. 
Published: July 2010

AbstractThis paper presents a stochastic procedure for the solution of groundwater flow through a random shallow semiconfined aquifer. Problems dealing with flow through a semiconfined aquifer with multiple random parameters subject to deterministic boundary conditions and domain recharge are investigated using perturbation techniques associated with boundary element methods. Both the transmissivity of the main aquifer and the resistance of the leaky layer are considered as random parameters. The perturbation boundary element method does not require specification of the probability density function of the parameters but only their expectations, variances and the covariance of the two parameters. To illustrate the applicability of the method, three simple numerical examples are presented. A one‐dimensional example is examined and compared with the exact solution, along with the perturbation solutions for two two‐dimensional flow problems.
Asymptotic confidence intervals from a preliminary test estimator
Authors: Ahmed S. E. , Kulperger R. J. 
Published: July 2010

AbstractA preliminary test estimator is a method of combining information from two experiments in a problem of estimating a parameter. The asymptotics of this estimator in the case of estimating a population mean is considered in a setting of a local alternative. Asymptotic confidence intervals are obtained using the asymptotic distribution.
A note on a characterization of the generalized log‐logistic distribution
Authors: El‐Saidi Mohammed A. , Singh Karan P. , Bartolucci Alfred A. 
Published: July 2010

AbstractThe log‐logistic distribution (LLD) is very useful in a wide variety of applications, especially in the analysis of survival data (O'Quigley and Struthers 1982; Bennett 1983; Cox and Snell 1989). The LLD is very similar in shape to the log‐normal distribution, however it has the advantage of having simple algebraic expressions for its survivor and hazard functions and a closed form for its distribution function. It is therefore more convenient than the log‐normal distribution in handling censored data. However, due to the symmetry of the log‐logistic distribution, it may be inappropriate for modelling censored survival date, especially for the cases where the hazard rate is skewed or heavily tailed. In this article we present a generalization of the LLD and refer to this as the generalized log‐logistic distribution (GLLD). The suggested GLLD reflects the skewness and the structure of the heavy tail and generally shows some improvement over the LLD. In addition, we generalize a result characterizing the log‐logistic distribution given by Shoukri, Mian, and Tracy (1988) and introduce two characterization theorems of the GLLD.
Assessing and modelling changes in rainfall erosivity at different climate scales
Authors: Diodato N. , Bellocchi G. 
Published: July 2010

AbstractAn understanding of the weather drivers of soil erosion necessitates an extended instrumental meteorological series and knowledge of the processes linking climate and hydrology. The nature of such linkages remains poorly understood for the Mediterranean region. This gap is addressed through a composite analysis of long‐term climatic controls on rain erosivity in the Calore River Basin (southern Italy) for the period 1869–2006. Based on a parsimonious interpretation of rainstorm processes, a model (comparable with the Revised Universal Soil Loss Equation) was adapted to generate erosivity values on different time‐aggregation scales (yearly and seasonal). The evolution of the generated series of cumulated and extreme erosivity events was assessed by two return period (T) quantiles via a 22‐year moving window analysis (low return period, T = 2 years; high return period, T = 50 years). Erosivity extremes are shown to be characterized by increasing yearly trends (at a 100‐year rate of ∼150 MJ mm ha–1 h–1 for T = 2 years and ∼800 MJ mm ha–1 h–1 for T = 50 years), especially during the spring and autumn seasons. Quantile patterns on the extremes are also shown to be decoupled from trends in the cumulated values. The Buishand test was applied to detect the presence of temporal change points, and a wavelet spectrum analysis used for time‐frequency localization of climate signals. A change‐point in the evolution of climate is revealed over the 1970s in the spring series, which correlates to a distinct rain erosivity increase. The results indicate that soil erosion risk tends to rise as a consequence of an escalation of the climate erosive hazard, predominantly between April and November (associated with cultivation and tillage practices). Copyright © 2009 John Wiley & Sons, Ltd.
Glacier reconstruction and mass‐balance modelling as a geomorphic and palaeoclimatic tool
Authors: Carr Simon J. , Lukas Sven , Mills Stephanie C. 
Published: July 2010

AbstractThe reconstruction of former mountain glaciers has long been used to examine the implications of rapid climate shifts, for example at the last glacial–interglacial transition, and for evaluating asynchronous behaviour of mountain glaciers compared with mid‐latitude ice sheets during the Late Quaternary. Glacier reconstruction has also been used as a source of palaeoclimatic information, based on the recognition of empirical relationships between glaciers and climate. This paper reviews the application and implications of a recently revised method of glacier reconstruction (Carr and Coleman, 2007), based around glaciological principles of mass‐balance. This study examines how this approach can be used to test geomorphological interpretations of former mountain glaciation and also to infer precipitation fields at sites of former glaciation. Sites of Younger Dryas niche and icefield glaciation in the British Isles demonstrate how this method can verify interpretations of marginal glaciation and begin to understand the different behaviour of outlet glaciers within the same environmental regime. Examination of a site of former niche glaciation in Southern Africa demonstrates how glacier reconstruction may be used to infer annual and seasonal precipitation values and strongly supports the idea that winter precipitation in Lesotho and SE South Africa was substantially greater than present‐day values during the last glacial cycle. Copyright © 2010 John Wiley & Sons, Ltd.
Field and laboratory studies on alpine soil erodibility, southern Rocky Mountains, Colorado
Authors: Summer Rebecca M. 
Published: July 2010

AbstractSoil erodibility has been studied on the alpine tundra of Trail Ridge in the southern Rocky Mountains, Colorado. Field experiments were conducted using a portable rainfall simulator to estimate an erodibility index (grams of detached soil per unit area) at 71 sites. The index determined on eight soil types allowed discrimination of a high erodibility group (mean index of 18.9 g), moderate or transitional group (mean index of 10.1 g), and one low group (mean index of 4.5 g). Laboratory measurements of physical propertiesMdashtexture, water absorption capacity, organic carbon, and aggregationMdashwere compared with the erodibility index and results of simple and multiple regressions showed that 29 per cent of the variance in erodibility is explained by the measured variables, the strongest correlation (r=0.42) being associated with aggregation. Unexplained variability (71 per cent) may be due in part to unmeasured soil properties, non‐linearity in the data, random processes, bias, and experimental error. These correlations represent a beginning in understanding factors influencing alpine soil erodibility. The results suggest that field measurement is still the most satisfactory method of estimating an erodibility index and that laboratory surrogates for this index are not readily applicable in this environment.
Spatial and seasonal aspects of beach stability
Authors: Carr A. P. , Blackley M. W. L. , King H. L. 
Published: July 2010

AbstractRecent work at three contrasting sites in England and Wales has shown characteristics atypical of those frequently reported elsewhere. These differences are:

(a) Taking each entire beach system there is no uniform trend of erosion or accretion, nor a progressive variation in beach elevation or volume alongshore, from one survey to the next. However, for Swansea Bay the ‘long‐term’ (i. e. 18 months) range in profile height along that stretch of coast where the alignment of the beach is normal to the direction of wave approach, correlates well with computed wave energy derived from relevant offshore wave directions.
(b) While beach variability is greatest during the ‘winter’ (i. e. storm) period there is no overall tendency for a drawdown of sediment from the intertidal zone at that time. Response times are relatively short. Thus high beach levels need not necessarily be associated with ‘summer’ conditions.
(c) Although in Swansea Bay there is a tendency for the beach height to fluctuate least at mid‐tide level this is not true of the other two sites. In no area does sediment eroded from the upper exposed part of the beach regularly appear to be deposited on the lower exposed part, or vice versa.
Height distortion and the sedimentation of dust on topographic scale models: Considerations and simulations
Authors: Goossens Dirk 
Published: July 2010

AbstractThe study focuses on the effect of height distortion of a scale model on the sedimentation of natural dust (loess) on that model, when dust storm simulation experiments are conducted in a wind tunel. A scale model of a very simple topographic feature (symmetrical hill) has been used first. Both the air‐flow field over the hill and the loess deposition pattern on the hill are examined in detail for four different height distortion cases. Later on, the effect of height distortion in complex topography in discussed.The results of the experiments indicate that height distortion has an important effect on both the air‐flow field and the loess sedimentation pattern. Height distortion must therefore, in principle, be avoided, unless it is necessary to meet the flow simulation requirements during the experiment or to intensity the contrasts in the sedimentation pattern on the scale model surface.For complex, hilly topography, a not‐too‐excessive height distortion may be allowable (especially in the case of very high horizontal scale reductions), but for open areas, where topographic features are situated relatively far from each other, great care must be taken in extrapolating wind tunnel results to the field.
Development of formulated reference sediments for freshwater and estuarine sediment testing
Authors: Suedel Burton C. , Rodgers John H. 
Published: July 2010

Abstract
Sediments collected at various field locations may have chemical and physical constituents that influence test results and may contain organisms that cannot be readily removed. Thus, reference sediments are needed that can be formulated to match diverse freshwater and estuarine sediments encountered in comprehensive testing programs. This research evaluated formulated reference sediments in terms of (a) their ability to match field-collected sediments both chemically and physically; (b) their suitability as habitat (survival and reproduction) for typical invertebrate toxicity testing species (Hyalella azteca Saussure, Chironomus tentans Fabricius, and Daphnia magna Straus) during chronic exposures; and (c) their suitability as a substrate for Hyalella azteca, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia Richard, and Pimephales promelas Rafinesque in 14-d whole-sediment exposures. Formulated reference sediments were prepared to match naturally occurring sediments with respect to particle-size distribution, organic matter, organic carbon, pH, solids, CEC, but not redox potential. After preparation, a conditioning period of at least 7 d was required for pH stabilization of formulated reference sediments. In culture experiments, formulated reference sediment was suitable for Hyalella azteca, Chironomus tentans, and Daphnia magna survival and reproduction for 56, 40, and 28 d, respectively. Hyalella azteca, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia and Pimephales promelas survival was ≥88% in 14-d exposures to formulated reference sediment. Formulated reference sediments may reduce some unexplained physical, chemical, or biological “toxicity” of field-collected sediments (e.g., organic matter) that may influence toxicity testing results.