A new method for the improvement of data production in phytochemical analysis

Introduction – The use of the average analytical signal for the construction of curves by the least squares method (LSM) over the standard addition method (SAM) is widespread. It would be advantageous, however, to find a way to avoid intermediary averages, which are known to be the cause of significant increases in standard deviations (SD). Objective – To develop a protocol that uses all gathered data to create curves by LSM over SAM. To use Excel^® for the estimation of y = mx + b and R² rather than using LSM equations for the SD of m, x and b. Methodology – The level of lead (II) in the bark (cork) of Quercus suber Linnaeus was determined using differential pulse anodic stripping voltammetry (DPASV). Three current samples were taken for each of the four standard additions. These signals were combined for adjustment by LSM. The results were compared with those obtained after averaging the current for each addition, and the expression of uncertainty in the measurements determined. Results – The new method shows an expanded uncertainty of ± 0.3321 μg/g (nearly 1.42%). The difference between the results obtained by the new and the old method is 0.01 μg/g (23.41 and 23.40 μg/g). The limit of detection changed approximately from 4.8 to 4 μg/g and the relative SD approximately from 9 to 6%. Conclusion – The absence of intermediary averages in curves improved the determination of lead (II) in cork by DPASV. Estimation of SD only with LSM equations produced results that were significantly worse. The changes are large enough to transform an apparently internally non‐validated procedure (repeatability for precision) into an internally validated procedure. Copyright © 2009 John Wiley & Sons, Ltd.     

Production and Purification of the Extracellular Ribonuclease of Bacillus Amyloliquefaciens (Barnase) and its Intracellular Inhibitor (Barstar) II. Barstar

Procedures are reported for the extraction and purification of barstar, the intracellular inhibitor of barnase, the extracellular ribonuclease of Bacillus amyloliquefaciens, (a strain formerly erroneously classified as B. subtilis, strain H), from frozen acidified cells obtained during the isolation of barnase¹. Methods include affinity chromatography on agarose to which barnase is covalently bound. Experiments relating to the purity, molecular weight, and amino acid composition of the product are reported.     

Tests of Independence and Zero Correlations Among P Random Variables

Suppose it is desired to determine whether there is an association between any pair of p random variables. A common approach is to test H₀ : R = I, where R is the usual population correlation matrix. A closely related approach is to test H₀ : R_pb = I, where R_pb is the matrix of percentage bend correlations. In so far as type I errors are a concern, at a minimum any test of H₀ should have a type I error probability close to the nominal level when all pairs of random variables are independent. Currently, the Gupta-Rathie method is relatively successful at controlling the probability of a type I error when testing H₀: R = I, but as illustrated in this paper, it can fail when sampling from nonnormal distributions. The main goal in this paper is to describe a new test of H₀: R_pb = I that continues to give reasonable control over the probability of a type I error in the situations where the Gupta-Rathie method fails. Even under normality, the new method has advantages when the sample size is small relative to p. Moreover, when there is dependence, but all correlations are equal to zero, the new method continues to give good control over the probability of a type I error while the Gupta-Rathie method does not. The paper also reports simulation results on a bootstrap confidence interval for the percentage bend correlation.     

Legionella pneumophila in Thermal Spa – Methodological Aspects of Sampling and Analysis

The aim of the study was to check the occurrence of Legionella pneumophila in thermal water and to compare different analytical methods of its determination and/or quantification used in different laboratories. The research has shown that there are noticeable differences between results from culture method, qPCR, and FISH. Significant influence on the results has got analysts qualification, samples preparation, and equipment parameters. Very important is also the homogeneousness of the samples. qPCR or FISH method can be used as a preliminary, quick study, for identification of Legionella in water samples but the results obtained should be confirmed by culture method.     

Determination of chemical biodegradation by direct and indirect methods

Summary Degradation of 10 organic chemicals by pre-acclimated microorganisms in BOD dilution water was determined directly by UV spectrophotometry and indirectly by a modified BOD method. Residual chemical concentrations were periodically measured and pseudo-first-order biodegradation rate constants (k ₁) were calculated. Thek ₁ spectrophotometry values ranged from 0.006/h to 0.077/h andk ₁-BOD values from 0.002/h to 0.043/h for 1-methylnaphthalene and indole, respectively. The ratios ofk spectrophotometry to k₁-BOD were between 1.5 for salicylic acid and 3.0 for 1-methylnaphthalene with a mean of 2.7. A significant (=0.001) linear correlation (r ²=0.854,F=46.630) existed between the two sets of rate constants. Results from this study suggest that the modified BOD method may be used to estimate chemical biodegradation rates in synthetic media.     

A comparison of two methods for measuring vessel length in woody plants

Vessel lengths are important to plant hydraulic studies, but are not often reported because of the time required to obtain measurements. This paper compares the fast dynamic method (air injection method) with the slower but traditional static method (rubber injection method). Our hypothesis was that the dynamic method should yield a larger mean vessel length than the static method. Vessel length was measured by both methods in current year stems of Acer, Populus, Vitis and Quercus representing short‐ to long‐vessel species. The hypothesis was verified. The reason for the consistently larger values of vessel length is because the dynamic method measures air flow rates in cut open vessels. The Hagen–Poiseuille law predicts that the air flow rate should depend on the product of number of cut open vessels times the fourth power of vessel diameter. An argument is advanced that the dynamic method is more appropriate because it measures the length of the vessels that contribute most to hydraulic flow. If all vessels had the same vessel length distribution regardless of diameter, then both methods should yield the same average length. This supports the hypothesis that large‐diameter vessels might be longer than short‐diameter vessels in most species.     

Effective number of pollen parents in clonal seed orchards

Summary A method for quantifying mating behavior in clonal seed orchards of forest tree species is presented. It involves the estimation of effective numbers of pollen parents from seed samples collected from individual ramets in such orchards. These effective numbers are variance effective numbers for populations of male gametes that are successful in uniting with ovules to produce viable seed. Three such effective numbers are defined for clonal seed orchards:N _p (a) for male gamete populations for ramets within clones,N _p (b) for male gamete populations for clones, andN _p (c) for male gamete populations for entire orchards. Estimators for these effective numbers and for standardized variances of allele frequencies in the male gametic populations are presented. Expressions are also given for the confidence intervals for each of the three effective numbers. Estimates of these parameters and the corresponding confidence intervals for two seed orchards are presented and interpreted.     

昆虫杆状病毒表达系统中阳性重组病毒的筛选

近年来,随着杆状病毒表达系统的普遍应用,阳性重组病毒筛选方法也有了很大的改进,从过去的经验性的ocu⁺／ocu^-空斑表型筛选发展到根据颜色差异,药物抗性,抗生素抗性等等筛选重组病毒.同源重组过程也可在大肠杆菌或酵母甚至体外进行,大大提高了重组率,由于重组率是如此之高,有些方法可以免去繁琐的空斑选择,很快得到重组病毒的纯培养.文章对各种筛选方法进行了比较,并指出各自的优缺点.     

A novel method for assessing the effect of photoperiod and temperature on reproductive biology of the predators Hippodamia variegata (Coleoptera: Coccinellidae) and Micromus tasmaniae (Neuroptera: Hemerobiidae)

A novel experimental approach for the simultaneous investigation of the effects of photoperiod and temperature showed evidence of diapause in Hippodamia variegata Goeze but not in Micromus tasmaniae Walker. Results are discussed in relation to their potential as greenhouse biocontrol agents.     

The Method of Unweighted Means in Unbalanced Analysis of Variance

For factorial experiments with unbalanced data the method of unweighted means is an alternate method of analysis which is computationally simpler than likelihood ratio based F-tests. The quality of the null approximation to the F-distribution of the statistic for the method of unweighted means and the power of this test relative to the likelihood ratio test are discussed. Recommendations are made of when in the course of data analysis the superior operating characteristics of the likelihood ratio test may not outweigh the computational simplicity of the method of unweighted means test.     

Pathways for Electron Tunneling in Cytochrome c Oxidase

Warburg showed in 1929 that the photochemical action spectrum for CO dissociation from cytochrome c oxidase is that of a heme protein. Keilin had shown that cytochrome a does not react with oxygen, so he did not accept Warburg's view until 1939, when he discovered cytochrome a ₃. The dinuclear cytochrome a ₃-Cu_B unit was found by EPR in 1967, whereas the dinuclear nature of the Cu_A site was not universally accepted until oxidase crystal structures were published in 1995. There are negative redox interactions between cytochrome a and the other redox sites in the oxidase, so that the reduction potential of a particular site depends on the redox states of the other sites. Calculated electron-tunneling pathways for internal electron transfer in the oxidase indicate that the coupling-limited rates are 9×10⁵ (Cu _A a) and 7×10⁶ s^–1 (a a ₃); these calculations are in reasonable agreement with experimental rates, after corrections are made for driving force and reorganization energy. The best Cu_A-a pathway starts from the ligand His204 and not from the bridging sulfur of Cys196, and an efficient a-a ₃ path involves the heme ligands His378 and His376 as well as the intervening Phe377 residue. All direct paths from Cu_A to a ₃ are poor, indicating that direct Cu_A a ₃ electron transfer is much slower than the Cu_A a reaction. The pathways model suggests a means for gating the electron flow in redox-linked proton pumps.     

Analysis of foraging movements of Atlantic bluefin tuna (<Emphasis Type="Italic">Thunnus thynnus</Emphasis>): individuals switch between two modes of search behaviour

We investigate the application of quantitative techniques for distinguishing adaptive search behaviour in Atlantic bluefin tuna (Thunnus thynnus). The analysis demonstrates the application of a novel spectral analysis technique for resolving and measuring periodicity in animal behaviour patterns. Two different search strategies are identified that include regulation of turning (klinokinesis) and speed (orthokinesis). Our results provide evidence that bluefin tuna attempt to optimize their searching efficiency through adjustments in the duration and timing of switching between these two searching strategies. Repetitive, diurnal deep dives were also found to coincide with switching of search behaviour. Additional tracking experiments with larger sample sizes are needed to better identify how individuals switch between the two search strategies and how such decisions may collectively improve the searching and foraging efficiency of their schools (synchrokinesis, social taxis) in response to changes in the size or composition of prey aggregations.     

Robustness of Statistical Methods II. Methods for the one-Sample Problem

This paper presents a new exact method of the investigation of the robustness in the one-sample-case of the u-, t- and χ²-statistics for discrete alternatives to the underlying normal distribution. First results for sample sizes up to n = 230 are given.     

Bacteriophage-receptor binding proteins for multiplex detection of Staphylococcus and Enterococcus in blood

Healthcare-associated infections (HCAIs) affect hundreds of millions of patients, representing a significant burden for public health. They are usually associated to multidrug resistant bacteria, which increases their incidence and severity. Bloodstream infections are among the most frequent and life-threatening HCAIs, with Enterococcus and Staphylococcus among the most common isolated pathogens. The correct and fast identification of the etiological agents is crucial for clinical decision-making, allowing to rapidly select the appropriate antimicrobial and to prevent from overuse and misuse of antibiotics and the consequent increase in antimicrobial resistance. Conventional culture methods are still the gold standard to identify these pathogens, however, are time-consuming and may lead to erroneous diagnosis, which compromises an efficient treatment. (Bacterio)phage receptor binding proteins (RBPs) are the structures responsible for the high specificity conferred to phages against bacteria and thus are very attractive biorecognition elements with high potential for specific detection and identification of pathogens. Taking into account all these facts, we have designed and developed a new, fast, accurate, reliable and unskilled diagnostic method based on newly identified phage RBPs and spectrofluorometric techniques that allows the multiplex detection of Enterococcus and Staphylococcus in blood samples in less than 1.5 hr after an enrichment step.     

Some Frequentist Properties of a Bayesian Method in Clinical Trials

Interim analysis in clinical trials involving two treatments are commonplace nowadays. Concerns from different points of view are widely seen in the literature. With a Bayesian approach there is no consideration of type I error and no power calculation. In contrast, there is no difficulty or arbitrariness in picking a prior distribution with a classical approach. In this paper, however, a stopping rule based on the Bayesian approach is discussed from a classical point of view. In specific, we consider application to normal sampling analyzed in stages and demonstrate the role of the prior distributions. In the first part of the paper, we define the stopping rules based on the posterior probabilities. We then develop the stopping boundaries in explicit forms, which can be easily computed with a hand calculator and a standard normal probability distribution table. We also summarize the frequency characteristics of this stopping rule into several results. The major question that is addressed in the second part of the paper is: how will a prior affect the results of a clinical trial study based on the posterior probabilities? The criteria for assessment will be strictly of a Neyman-Pearson kind. We use N(v, τ₂) as the prior distribution for the difference between treatments, δ. We show that the test is unbiased if v = 0 or τ = ∞. In addition, some rather obvious facts are again summarized into a couple of results. We also discuss, with a table and a figure, the power functions of non-trivial cases with extreme v and τ using a numerical example.     

Film analysis of activated sludge microbial discs by the Taguchi method and grey relational analysis

A biofilm model with substrate inhibition is proposed for the activated sludge growing discs of rotating biological contactor (RBC); this model is different from the steady-state biofilm model based on the Monod assumption. Both deep and shallow types of biofilms are examined and discussed. The biofilm models based on both Monod and substrate inhibition (Haldane) assumptions are compared. In addition, the relationships between substrate utilization rate, biofilm thickness, and liquid phase substrate concentration are discussed. The influence order of the factors that affect the biofilm thickness is studied and discussed by combining the Taguchi method and grey relational analysis. In this work, a Taguchi orthogonal table is used to construct the series that is needed for grey relational analysis to determine the influence priority of the four parameters S _B , kX _f , K _s, and K _i .     

A comparison of survey and focal follow methods for estimating individual activity budgets of cetaceans

Activity budget data are essential for determining behavioral responses to physiological and ecological variables. Yet, few studies are available to investigate the robustness, accuracy, and biases of the methods used to estimate activity budgets for cetaceans. In this study, we compare activity budgets of 55 adult female bottlenose dolphins in Shark Bay, Australia derived from two methods: surveys (n = 6,903) and focal follows (n = 1,185, totaling 2,721 h of observation). Activity budgets estimated from survey data differed in all behavioral states compared to focal follow data. However, when controlling for temporal autocorrelation, only time spent socializing and time spent traveling remained disparate between the methods. To control for biases associated with assigning group‐level behavior to individuals, we also compared survey and focal follow activity budgets for lone females. Here we found differences between methods in time spent foraging and traveling regardless of whether we controlled for temporal autocorrelation, which suggests detection biases likely play a role in explaining differences in activity budget estimates between the two methodologies. Our results suggest that surveys are less representative of individual‐level activity budgets, and thus, when individual‐level knowledge about behavior is needed, focal follows are preferred.     

Evaluation of the usefulness of a new direct immunofluorescence assay (ScanVIT‐Legionella™) for monitoring hospital water systems contaminated with Legionella spp.

Aims: To compare the efficiency of the ScanVIT‐Legionella^? test (Vermicon, Munich, Germany) vs a conventional culture method for the quantification of Legionella spp. in hospital water samples in daily hospital practice. Methods and Results: The detection of Legionella spp. takes place on a cultivated filter brought into contact with dye‐marked gene probes. The results are analysed under fluorescence microscopy. Bacteria that light up green belong to the genus Legionella; those that light up both green and red belong to the species Legionella pneumophila. Our results showed that the ScanVIT test has a sensitivity of 90%; agreement between the two methods was 82%. In the 48 samples that tested positive with both methods, the Legionella concentration detected by the culture method was consistently higher. A statistically significant difference between the results obtained with the two test methods emerged at the Wilcoxon test (P < 0·001). Conclusion: The ScanVIT test may be recommended for investigating the presence of Legionella by qualitative testing. Significance and Impact of the Study: Given the simplicity of colony identification by fluorescence, the ScanVIT test can be used in laboratories where staffs are not experienced in identifying typical colonies of Legionella.     

Bioaccumulation of lindane and hexachlorobenzene by the oligochaetes Enchytraeus luxuriosus and Enchytraeus albidus (Enchytraeidae,Oligochaeta, Annelida)

The uptake of chemicals in soil organisms, especially earthworms, has been studied many times. However, in Europe no internationally accepted standardised test guideline for the assessment of bioaccumulation in the soil ecosystem exists. Therefore, the German Federal Environmental Agency recently funded a project in which a standardisable test method for measuring bioaccumulation of chemicals using earthworms and enchytraeids is being developed. In this contribution, initial results with the new method are presented, using two model chemicals (the insecticide lindane and the fungicide hexachlorobenzene). Two enchytraeid species (Enchytraeus luxuriosus and Enchytraeus albidus) were selected as test organisms due to their easy handling and their important ecological role in the soil compartment. Artificial soil and a natural standard soil were used as test substrates. Test concentrations were based on previous results of acute and reproduction toxicity tests performed with the same species. Uptake as well as the elimination of the test substances were examined under standardised conditions in a closed test system. The first results show that both chemicals were accumulated considerably by both enchytraeid species. The bioaccumulation factors (BAFs) of lindane and hexachlorobenzene found for enchytraeids are significantly higher compared to those for lumbricid earthworms. Evaluation of the preliminary data suggests that the smaller species E. luxuriosus accumulated the two chemicals to a greater extent than E. albidus. In most cases, both chemicals were eliminated completely. The use of this new test method appears suitable for the ecotoxicological risk assessment of bioaccumulative chemicals.     

Evolution of mandibular arcades: a statistical study

The alveolar arcades of a large number of fossil mandibles including Australopithecus and hominids fromHomo habilis andHomo erectus up to modern man have been characterized by fourteen cartesian points each representing a tooth. From these points, dimensions and angles have been calculated. These values are correlated to the geological age of the fossils. A linear dependance of dimensions and angles on the logarithm of age has been found. These results are discussed in the framework of a continuous gradual development within genus Homo and contrasted to prehominid data. Using these mean arcades and selected angles thereon the European and the AfroasiaticHomo erectus are compared and contrasted to the Neandertalians.