bluuebunny/crossref_metadata_2025 huggingface dataset:
A relaxation of the gamma frailty (Burr) model
Authors: Perperoglou Aris , van Houwelingen Hans C. , Henderson Robin
Published: August 2006

Frailty models are used in univariate data to account for individual heterogeneity. In the popular gamma frailty model the marginal hazard has the form of a Burr model. Although the Burr model is very useful and can offer insight on the data, it is far from perfect. The estimation of the covariate effects is linked to the baseline hazard and this makes the model coefficients hard to interpret. At the same time, the frailties are assumed constant over time, while biological reasoning in some cases may indicate that frailties may be time dependent. In this paper we present a relaxation of the Burr model which is based on loosening the link between the estimation of the covariate effects and the baseline hazard. This can be achieved by replacing the cumulative baseline hazard in the Burr model by a set of time functions, and the frailty variance by a vector of coefficients directly estimated from the data using a partial likelihood. We illustrate the similarities of the model with the Burr model and a further extension of the latter, a model with an autoregressive stochastic process for the frailty. We compare the models on simulated data sets with constant and time‐dependent frailties and show how the relaxed Burr models performs on two different real data sets. We show that the relaxed Burr model serves as a good approximation to the Burr model when the frailty is constant, and furthermore it gives better results when the frailty is time dependent. Copyright © 2006 John Wiley & Sons, Ltd.
Change from baseline and analysis of covariance revisited
Authors: Senn Stephen
Published: August 2006

The case for preferring analysis of covariance (ANCOVA) to the simple analysis of change scores (SACS) has often been made. Nevertheless, claims continue to be made that analysis of covariance is biased if the groups are not equal at baseline. If the required equality were in expectation only, this would permit the use of ANCOVA in randomized clinical trials but not in observational studies. The discussion is related to Lord's paradox. In this note, it is shown, however that it is not a necessary condition for groups to be equal at baseline, not even in expectation, for ANCOVA to provide unbiased estimates of treatment effects. It is also shown that although many situations can be envisaged where ANCOVA is biased it is very difficult to imagine circumstances under which SACS would then be unbiased and a causal interpretation could be made. Copyright © 2006 John Wiley & Sons, Ltd.
A review of studies on the electric field and the current induced in a human body exposed to electromagnetic fields
Authors: Takuma Tadasu , Watanbe Soichi , Kawamoto  , Yamazaki Kenichi
Published: August 2006

How high an electric field or current is induced inside a human body when exposed to an electromagnetic field has recently attracted much attention. The background for this is twofold; concern about the possible health effects of electromagnetic fields (usually called ‘EMF issues’), and their positive application to medical treatment or new research subjects. This paper reviews various aspects related to this topic in terms of the following items: basic formulas for field calculation, effect of electromagnetic fields, calculation methods, an Investigation Committee in the IEEJ, and future research subjects. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Technology interaction of Electrical Engineering
Authors: Fumio Arakawa , Masao Takahashi
Published: August 2006

The paper reviews the global activities of the Technical Committee for History of Electrical Engineering (HEE) in Institute of Electrical Engineers of Japan (IEEJ) to discuss its future activities. Introducing HEE global activities in the Maui Meeting (MM) and International Conference on Electrical Engineering (ICEE), the paper discusses the framework of the International Joint Study Programme for History of Technology Interaction (IJSP/HTI) on the basis of its current study conducted by the Investigation Committee for International Joint Study for History of Technology Interaction (IC/HTI). It concludes the discussion with the view that the study of history could serve as a foundation for us to achieve global contributions in the field of engineering as well. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Portable application of thermal plasma and arc discharge for waste treatment, thermal spraying and surface treatment
Authors: Iwao Toru , Yumoto Motoshige
Published: August 2006

Thermal plasma and arc discharge have numerous useful characteristics related to their high temperature and intense radiation. Many applications have been developed. Recently, a portable twin‐torch plasma arc furnace for waste treatment, thermal spraying torches, steam plasma torches, and surface treatment of low‐pressure arc was developed. This paper describes the recent development of a portable application of thermal plasma and arc discharge. The portable device can treat wastes and perform thermal spraying and surface treatments on site. This technology is expected to become more attractive. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Braun‐tube display of Katakana ‘i’ by Kenjirou Takayanagi in the early days of Television Development
Authors: Suematsu Yasuharu
Published: August 2006

The age of television, especially opto‐electronics, began with the development of electronic image display technology with Braun‐tube (CRT). Kenjirou Takayanagi says that in the early stages of its development, he succeeded in putting up a Japanese character ‘τ’ (which is pronounced as ‘i’) on a cathode‐ray tube (CRT) as an electric image for the first time in December 1926. Electronic type television technologies have advanced through the development of the television camera tube and electronic image display technology carried out by Philo T. Farnsworth, Vladimir K. Zworykin, Kenjirou Tayayanagi and others. As a result of these developments, the electronic image display device has developed into ‘a man‐machine interface’ and has also evolved into a key technology of information and telecommunication networks.

This paper is an edited version of the paper ‘Electronic Image Display Developed as Key Device for Information Technology ∼ First Braun‐Tube‐Display of Katakana ‘i’ by Kenjirou Takayanagi in early day of Television Development and its effects’ by Y. Suematsu, Journal of Institute of Image and Television Engineers, vol. 59, No.11, pp.1564–1568. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Characteristics of a two‐dimensional integrated magnetic sensor for position sensing and motor control
Authors: Kimura Takayuki , Takasaki Keigo , Masuzawa Toru
Published: August 2006

Two‐dimensional integrated magnetic sensors for position sensing were designed and fabricated with the standard 0.35‐µm CMOS process on silicon. One such type is the n‐type Hall sensor that uses an inversion layer under the gate oxide of the MOSFET. The Hall sensors were arrayed (64 × 64), and the control digital circuits and output amplifier were also integrated into the same chip. ‘One pixel’ was 50 × 50 µm, and the entire chip was 4.9 × 4.9 mm. The sensitivity of one of these sensors was 2.7 mV/(mA·kG). The two‐dimensional magnetic flux distribution was measured from the 5‐mm diameter Nd–Fe–B rare‐earth permanent magnet. About 42 s was required to measure one frame. The position of the magnet could be detected with the fabricated sensors. Magnetic sensors using an inversion layer in MOSFETs are useful for position sensing systems, but their noise characteristics, such as poor sensitivity, should be improved. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Improved method to simulate gradient in alumina packing fraction in alumina/epoxy composite fabricated by a centrifugal method
Authors: Hayashi Noriyuki , Sugahara Tetsuo , Tsuru Shin‐Ichiro , Hara Masanori
Published: August 2006

A centrifugal method was used to fabricate large‐scale functionally graded materials (FGMs) from solid‐particles/viscous‐matrix mixtures at room temperature. The conventional simulation procedure of the centrifugal process was improved by considering the dependency of the viscosity η of the mixture on the packing fraction νp of particle, the effects of arbitrary shape of the actual fillers on η, the statistical dispersion of the diameters of the actual fillers, and the formation and growth of the fully packed layer (FPL) near the FGM bottom. The new simulation method was applied to three centrifugal processes employed for experimental FGM fabrications from alumina/epoxy mixtures. The numerical profiles of νp are in good agreement with the experimental ones regardless of the shapes of fillers and 'ponding viscosity of the solutions without fillers, the total amount of fillers loaded, and the centrifugal conditions. The saturating nature of νp near the far end of the FGM column is also simulated with reasonable precision. Finally, the manner in which the particles exert varying influences on the gradient of νp is demonstrated: the particles exhibit different movements depending on their size. On the basis of these results, the effectiveness of the new simulation method proposed is confirmed for the modeling of similar processes involved in the fabrication of FGMs from solid‐particles/viscous‐matrix mixtures by the centrifugal method. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
The new EU merger regulation: Implications for EU‐U.S. merger strategies
Authors: Akbar Yusaf H. , Suder Gabriele G. S.
Published: August 2006

This article examines the implications of the new EU merger regulation (EU 139/2004) on international merger strategies. Important changes in the new regulation on both a substantive and procedural level are analyzed in the comparative context of EU and U.S. merger‐control policies. In particular, the article evaluates whether the “substantial impediment to effective competition” (SIEC) test in the new regulation implies convergence with the U.S. “substantial lessening of competition” (SLC) benchmark. In this context, the article develops scenarios for convergence between EU and U.S. merger‐control policies. The EU merger process has emerged against a background of significant political and institutional development in the European Union, and this is an important explanatory element in the development of competition policy in general and for the new merger regulation in particular. It also has implications for merger strategies examined at the end of the article. © 2006 Wiley Periodicals, Inc.
Assessing Russian consumers' imported versus domestic product bias
Authors: Thelen Shawn , Ford John B. , Honeycutt Earl D.
Published: August 2006

Data from a cross‐section of 438 Russian consumers were collected and analyzed to evaluate consumer preference for ten product types—five consumables and five durables. Results indicate that when Russian consumers consider purchasing a consumable product, consumer ethnocentrism levels and product characteristics reinforce each other, resulting in a strong domestic bias; however, these variables conflict with each other when consumers consider durable products, resulting in consumers exhibiting an inclination for imported durables. This indicates that product characteristics may influence product preference (domestic versus imported) more than consumer ethnocentrism levels. © 2006 Wiley Periodicals, Inc.
Characteristics of adopters and organizational changes
Authors: Askarany Davood
Published: August 2006

Adopting Rogers's (1995) diffusion model and the modified diffusion model presented by Askarany (2003), this article explores the impact of characteristics of adopters on the diffusion of administrative innovations in general and then examines their associations with the diffusion of balanced scorecard (as a proxy of administrative changes) in particular. Findings suggest that attributes of adopters significantly influence decision(s) to adopt (or not) administrative innovations. However, with particular reference to balanced scorecard, the findings indicate that attributes of adopters do not appear to remain as significant as before the decision was made. © 2006 Wiley Periodicals, Inc.
How similar is the world in the internet era? A comparison of e‐business in China, Russia, and Sweden
Authors: Fey Carl F. , Koning Alice de , Delios Andrew
Published: August 2006

Much has been written about how e‐business can serve as a strong homogenizing influence and essentially make the world into one market. Yet, little research has empirically investigated this question. This study seeks to describe e‐business activity in China, Sweden, and Russia to identify similarities and differences in the portfolios of e‐business applications in these countries. Our results indicate that different e‐business applications are emerging as more prevalent in different countries. © 2006 Wiley Periodicals, Inc.
Increased TCA cycle activity and reduced oxygen consumption during cytochrome P450‐dependent biotransformation in fission yeast
Authors: Drǎgan Cǎlin‐Aurel , Blank Lars M. , Bureik Matthias
Published: August 2006

Cytochrome P450s are haem‐containing monooxygenases that catalyse a variety of oxidations utilizing a large substrate spectrum and are therefore of interest for biotechnological applications. We expressed human CYP21 in fission yeast Schizosaccharomyces pombe as a eukaryotic model for P450‐dependent whole‐cell biotransformation. The resulting strain displayed strong steroid hydroxylase activity that was accompanied by contrary effects on respiration and non‐respiratory oxygen consumption, which combined to a significant decline in total oxygen consumption of the cells. While production of ROS (reactive oxygen species) decreased, the TCA cycle activity increased, as was shown by metabolic flux (METAFoR) analysis. Pentose phosphate pathway (PPP) activity was found to be negligible, regardless of growth phase, CYP21 expression or biocatalytic activity, indicating that NADPH levels in Sz. pombe are sufficiently high to support an exogenous P450 without adaptations of central carbon metabolism. We conclude from these data that neither oxygen supply nor NADPH availability are limiting factors in P450‐dependent biocatalysis in Sz. pombe. Copyright © 2006 John Wiley & Sons, Ltd.
Key physiological differences in Candida albicans CDR1 induction by steroid hormones and antifungal drugs
Authors: Larsen Bryan , Anderson Seth , Brockman Andrea , Essmann Michael , Schmidt Martin
Published: August 2006

The Candida albicans CDR1 gene, encoding an ABC transporter that functions as an efflux pump, is thought to be involved in pathogenic adaptation and uses mammalian hormones and other environmental cues to regulate its activity. Exposure of several clinical isolates of C. albicans to 1 × 10−8 M 17β‐oestradiol increased CDR1 expression and the isolates showed a positive correlation between oestrogen induction of CDR1 and growth in the presence of oestrogen. A reporter strain carrying the GFP gene under the control of the CDR1 promoter was used to analyse the effect of steroid hormones and antifungal drugs on CDR1 expression by flow cytometry. We found that among the many hormones tested, only oestradiol and progesterone induce CDR1 expression. CDR1 induction requires hormone concentrations greater than 10−8 M, a threshold reached in vivo only by progesterone. Using the GFP‐reporter strain, we show CDR1 induction by female but not male human serum and demonstrate that exposure of C. albicans to physiological concentrations of progesterone measurably increases resistance to fluconazole, miconazole and 5‐fluorouracil. Simultaneous exposure of C. albicans to hormones and antifungal drugs provided evidence that both agents induce CDR1 expression via different mechanisms with different saturation points. Copyright © 2006 John Wiley & Sons, Ltd.
Soluble forms of YlCrh1p and YlCrh2p, cell wall proteins of Yarrowia lipolytica, have β‐1,3‐glycosidase activity
Authors: Hwang Ji‐Sook , Seo Dong‐Hyuck , Kim Jeong‐Yoon
Published: August 2006

Crh1p and Crh2p of Saccharomyces cerevisiae are cell wall proteins covalently attached to cell wall glucan and are thought to be putative glycosidases involved in cell wall remodelling. We investigated whether YlCrh1p and YlCrh2p, the Yarrowia lipolytica proteins homologous to ScCrh1p and ScCrh2p, had the required glycosidase activity for cell wall biosynthesis and maintenance. Ylcrh1Δ and Ylcrh2Δ mutants showed sensitivity to compounds that interfere with cell wall construction. Soluble forms of YlCrh1p and YlCrh2p that lacked the C‐terminal consensus sequence for GPI anchoring showed glycosidase activity on laminarin, a substrate carrying β‐1,3‐glycosidic linkage. Our study suggests that the YlCrh1p and YlCrh2p may participate in cell wall biosynthesis and remodelling through their β‐1,3‐glycosidase activity. Copyright © 2006 John Wiley & Sons, Ltd.
Recombineering reagents for improved inducible expression and selection marker re‐use in Schizosaccharomyces pombe
Authors: Erler Axel , Maresca Marcello , Fu Jun , Stewart A. Francis
Published: August 2006

The fission yeast Schizosaccharomyces pombe is an excellent model organism for cell biology. However, its genetic toolbox is less developed than that of Saccharomyces cerevisiae. In the first part of this study we describe an improved inducible expression vector based on tetracycline regulation of the CaMV35S promoter, which is also capable of chromosomal integration and therefore works in minimal and in rich media. We found that anhydrotetracycline is a superior ligand for induction. Maximum expression levels were observed after 12 h in minimal media (EMM) and after 9 h in rich media (YES), which is faster than the nmt1 promoter system. The system was combined with a convenient recombineering‐based subcloning strategy for ease of cloning. In the second part we present four template plasmids, pSVEM‐bsd, pSVEM‐nat, pSVEM‐kan and pSVEM‐hph, which harbour four recyclable disruption cassettes based on the Cre recombinase lox71/66 strategy for use in PCR targeting methods. Cre‐mediated excision leaves a non‐functional mutant lox site in the genome, allowing the reiterative usage of these cassettes for multiple targetings. These cassettes are also configured with dual eukaryotic/prokaryotic promoters so that they can be used for recombineering in E. coli. Amongst other purposes, this permits the rapid and convenient creation of targeting constructs with much longer homology arms for difficult and complex targetings in the Sz. pombe genome. Copyright © 2006 John Wiley & Sons, Ltd.
A two‐step method for the introduction of single or multiple defined point mutations into the genome of Saccharomyces cerevisiae
Authors: Toulmay Alexandre , Schneiter Roger
Published: August 2006

The introduction of defined mutations into open reading frames (ORF) or non‐translated regions of the genome is important to study of the structure–function relationship of amino acid residues in proteins or that of sequence motifs at the genome level. We describe a simple two‐step method for the introduction of defined single or multiple point mutations into the genome of Saccharomyces cerevisiae. This method circumvents the need for plasmid‐based mutagenesis and thus ensures homogenous expression of the gene of interest within the cell population. It is based on the introduction of a selectable marker downstream of the gene of interest. This marker is then amplified with a gene‐specific primer that harbours the desired point mutation, creating a selectable marker‐tagged mutant version of the gene of interest. The mutant fragment is then integrated into the genome of a wild‐type strain through homologous recombination. Successive rounds of amplification of the mutant loci with primers that introduce additional point mutations upstream of existing mutations will generate multiple defined mutations within a single gene. As a proof of principle, we have employed this method to generate a temperature‐sensitive mutant version of the plasma membrane ATPase, pma1‐7, which bears two point mutations (Pro434Ala and Gly789Ser). Phenotypic analysis of a pma1‐7 haploid strain indicates that this allele has the same characteristics as the original pma1‐7 allele. It confers a temperature‐sensitive growth phenotype and the newly synthesized Pma1‐7 protein is unstable and rapidly degraded. Copyright © 2006 John Wiley & Sons, Ltd.
Nitrogen source and the retrograde signalling pathway affect detection, not generation, of the [URE3] prion
Authors: Edskes Herman K. , Naglieri Benedetta M. , Wickner Reed B.
Published: August 2006

[URE3] is an infectious (prion) inactive amyloid form of Ure2p, a regulator of nitrogen catabolism. [URE3] clones are selected on NH4+, using their derepressed expression of DAL5 to allow uptake of ureidosuccinate (USA). We previously reported that mks1Δ prevents generation of [URE3] and others reported that glutamate in the medium or the elevated glutamate in mks1Δ strains blocks [URE3] generation. We show here that elevated glutamate does not block [URE3] generation, but that neither does mks1Δ. Rather, a post‐transcriptional effect on DAL5 of mks1Δ through the retrograde regulation pathway prevents detection of [URE3] prion‐containing colonies. Moreover, the presence of both ammonia and glutamate blocks USA uptake in a known [URE3] strain, so that detection of the prion is prevented, rather than its generation. Copyright © 2006 John Wiley & Sons, Ltd.
Biological control of aphids and coccids: a comparative analysis
Authors: Hirose Yoshimi
Published: August 2006

A comparison of the biological control of aphids and coccids was carried out by analyzing success rates for the three major types of biological control, i.e., classical, augmentative, and conservational. Because of the higher intrinsic rates of increase for aphids versus coccids, the working hypothesis that biological control of aphids is less successful compared to coccids was adopted. However, this hypothesis was not supported by an analysis of classical biological control using the BIOCAT database. In this analysis, parasitoids were more successful than predators when used against either aphids or coccids, but the control of Icerya spp. with Rodolia spp. (predators) was highly successful. Some reasons for success of Rodolia spp. are adduced, but field studies on the long‐term population dynamics of Icerya–Rodolia systems are needed for determining the mechanisms of regulation. Comparative analyses of augmentative and conservational biological control of aphids and coccids were inconclusive, due to lack of adequate databases; some possible factors involved in the success of these types of biological control are discussed. It is suggested that parasitoids could be better control agents than predators in augmentative biological control of aphids in production greenhouses. Conservational biological control of either aphids or coccids should be aimed at enhancing populations of indigenous natural enemies, especially mobile generalist predators that are capable of keeping pace with mobile pests.
Intraguild predation: fiction or reality?
Authors: Kindlmann Pavel , Houdková Kateřina
Published: August 2006

Intraguild predation has become a major research topic in biological control. Quantification of multipredator interactions and an understanding of the consequences on target prey populations are needed, which only highlights the importance of population dynamics models in this field. However, intraguild predation models are usually based on Lotka–Volterra equations, which have been shown not to be adequate for modeling population dynamics of aphidophagous insects and their prey. Here we use a simple model developed for simulation of population dynamics of aphidophagous insects, which is based on the type of egg distribution made by predatory females, to estimate the real strength of intraguild predation in the aphidophagous insects. The model consists of two components: random egg distribution among aphid colonies, and between‐season population dynamics of the predatory species. The model is used to estimate the proportion of predatory individuals that face a conflict with a heterospecific competitor at least once during their life. Based on this, predictions are made on the population dynamics of both predatory species. The predictions are confronted with our data on intraguild predation in ladybirds.
Scaling up population dynamic processes in a ladybird–aphid system
Authors: Houdková Kateřina , Kindlmann Pavel
Published: August 2006

Here, we study how scaling up to the metapopulation level affects predictions of a population dynamics model motivated by an aphidophagous predator–aphid system. The model incorporates optimization of egg distribution in predatory females, cannibalism among their offspring, and self‐regulation of the prey population. These factors determine the within‐year dynamics of the system and translate the numbers of prey and predator individuals at the beginning of the season into their numbers at the end of the season at the level of one patch—one suitable host plant or a group of these. At the end of each season, all populations of prey and all populations of predators are mixed (this simulates aphid host‐alternation and ladybird migration to hibernation sites), and then redistributed at the beginning of the next season. Prey individuals are distributed at random among the patches as a “prey rain”, while adult predators that survived from the previous season optimize the distribution of their offspring, in that they prefer patches with sufficient amount of prey and absence of other predators. This redistribution followed by within‐season dynamics is then iterated over many seasons. We look at whether small‐scale trends in population dynamics predicted by this model are consistent with large‐scale outcomes. Specifically, we show that even on the metapopulation scale, the impact of predators on prey metapopulation is relatively low. We further show how the dates of predator arrival to and departure from the system affect the qualitative behaviour of the model predictions.
Ecological considerations for biological control of aphids in protected culture
Authors: Yano Eizi
Published: August 2006

Several braconid and aphelinid parasitoids, midges, lacewings, and ladybird beetles are used to control aphids in greenhouses. Here, I review three topics as ecological bases for the biological control of aphids in a protected culture: the preliminary evaluation of biological control agents, natural enemy release strategies, and the effects of intraguild predation (IGP) on biological control. A comparison of several parasitoid species was conducted to select agents for the biological control of aphids; the intrinsic rate of natural increase was a useful criterion in the preliminary evaluation. To compare predators as biological control agents, the aphid‐killing rate must be considered as a critical criterion, rather than reproductive criteria. The banker plant system (open rearing system) is used as a release method for Aphidius colemani and other natural enemies of aphids. Continuous release of parasitoid adults, which is the important characteristic of this method, has a stabilizing effect on population fluctuation in the aphid–parasitoid system. Two species of natural enemies can be used to control aphids in greenhouses. When one parasitoid and one predator are used simultaneously in a greenhouse, IGP of the parasitoid by the predator can occur, but the effect of IGP is less important in greenhouses than in the field.
Five‐year study of the genetic structure and demography of two subpopulations of the Japanese squirrel (Sciurus lis) in a continuous forest and an isolated woodlot
Authors: Tamura Noriko , Hayashi Fumio
Published: August 2006

The Japanese squirrel (Sciurus lis) is endemic to Honshu and Shikoku, Japan. In suburban environments this squirrel has tended to disappear from smaller and/or more isolated woodlots. In this study, genetic structure was compared from 1999 to 2004 for two subpopulations, one in a continuous mountain forest of western Tokyo and the other in a neighbouring woodlot isolated by a busy road. By sequencing 434 bp of the mitochondrial DNA control region of all 69 squirrels living in the two habitats, nine haplotypes were detected. Both the number of haplotypes and their genetic diversity were lower in the isolated woodlot (5 and 0.62, respectively) than in the continuous forest (8 and 0.79). Yearly comparisons revealed that only two to three haplotypes occurred simultaneously in the isolated woodlot whereas four to six were always found in the continuous forest, although the number of resident squirrels per year did not differ between the two sites. Haplotype dynamics revealed that the female population in the isolated woodlot was in a monotypic state for over two years before immigration of females with different haplotypes occurred. In the isolated woodlot immigration was thus restricted and turnover was lower, particularly among females. Such demographic factors seem to maintain the lower genetic diversity of the isolated subpopulation.
Relationship between bacterial and primary production in a newly filled reservoir: temporal variability over 2 consecutive years
Authors: Jugnia Louis‐B. , Sime‐Ngando T. , Devaux J.
Published: August 2006

Seasonal and spatial variations in bacterial abundance, biomass and production in a recently flooded reservoir were followed for 2 consecutive years, in conjunction with phytoplankton biomass (chlorophyll a) and activity (primary production). Between the 2 years of the study, the mean value of primary production remained constant, while those of the chlorophyll a concentration, bacterial abundance (BA), bacterial biomass (BB) and bacterial production (BP) decreased. The observed trends of the bacterial variables were linked to changes in the relative importance of allochthonous dissolved organic matter. Moreover, this factor would explain discrepancies observed between the slope of the model II regression equations established from results of the present study and those of the predictive models from the literature, relating to bacterial and phytoplankton variables. An estimate of the carbon budget indicated that 22 and 5% of the ambient primary production in the Sep Reservoir might be channeled through the microbial loop via BP during the 1st and 2nd year of the study, respectively. We conclude that heterotrophic BP in the Sep Reservoir may, on occasion, represent a significant source of carbon for higher order consumers.
Evaluation of myocardial alterations using the enzymatic profile of elderly long-distance runners
Authors: Souza C. A. , Garcez-Leme L. E.
Published: August 2006

Elderly population often is encouraged to practice sports in preventing cardiovascular diseases. However, evidences exist that intense physical efforts are related with a higher risk for acute myocardial infarction and sudden death. Biological markers for myocardial injury was analyzed in a group of 15 elderly athletes without a history of coronary artery disease, who participated in the 77th International Sao Silvestre race (15,000 m) in Sao Paulo City. A statistical difference was observed between total CPK activity levels before the run, immediately after the run, and some time later. Similar results were observed in the concentration of CK-MB mass. The cardiac troponin I (TnI-c) levels remained unchanged and within normal limits during the same time periods. The results of the present study showed no evidence of myocardial injury in elderly subjects without a history of coronary artery disease after participating in long-distance runs, as confirmed by the analysis of TnI-c levels. The increase in total CPK activity levels and the concentration of CK-MB mass do not represent myocardial injury in these subjects.
Diabetes, aging and physical activity
Authors: Frier Bruce , Yang Pearl , Taylor Albert W.
Published: August 2006

Diabetes mellitus (DM) is a metabolic disease affecting the regulation of insulin and glucose causing a disruption in the normal control of counterregulatory hormones and macronutrients, resulting in blood glucose accumulation. Metabolic deregulation leads to the production of noxious substances that have a particular propensity for damaging vascular and nervous structures. Physiological changes observed with aging are correlated with a concomitant increase in DM and its associated complications. Long-term complications, including peripheral and central neuropathies, micro- and macrovascular damage, retinopathy, and nephropathy are the major causes of mortality in diabetics [cardiovascular disease (CVD) being the primary complication causing death in this population]. All-cause mortality is three to four times greater in the DM population; hence, management of DM is of timely importance, particularly with a projected prevalence increase of 134% within the next 25 years among individuals over the age of 65 years. Exercise modalities, including endurance and resistance training, were employed to improve glycemic/metabolic control and to ameliorate the progression of DM-related complications. Several risk factors, including glucose levels, blood pressure, lipid/cholesterol profile, and BMI, are reportedly improved with these modes of exercise. However, not all studies demonstrate an improvement in risk factors, but consistently note improvement in complications and a reduction of DM incidence. There is convincing evidence that exercise, with or without specific improvements to traditional DM-related risk factors, is an effective therapy for the management of DM.
Referred pain from trapezius muscle trigger points shares similar characteristics with chronic tension type headache
Authors: Fernández‐de‐las‐Peñas César , Ge Hong‐You , Arendt‐Nielsen Lars , Cuadrado Maria Luz , Pareja Juan A.
Published: August 2006

Referred pain and pain characteristics evoked from the upper trapezius muscle was investigated in 20 patients with chronic tension‐type headache (CTTH) and 20 age‐ and gender‐matched controls. A headache diary was kept for 4 weeks in order to confirm the diagnosis and record the pain history. Both upper trapezius muscles were examined for the presence of myofascial trigger points (TrPs) in a blinded fashion. The local and referred pain intensities, referred pain pattern, and pressure pain threshold (PPT) were recorded. The results show that referred pain was evoked in 85% and 50% on the dominant and non‐dominant sides in CTTH patients, much higher than 55% and 25% in controls (P<0.01). Referred pain spread to the posterior‐lateral aspect of the neck ipsi‐lateral to the stimulated muscle in both patients and controls, with additional referral to the temple in most patients, but none in controls. Nearly half of the CTTH patients (45%) recognized the referred pain as their usual headache sensation, i.e. active TrPs. CTTH patients with active TrPs in the right upper trapezius muscle showed greater headache intensity and frequency, and longer headache duration than those with latent TrPs. CTTH patients with bilateral TrPs reported significantly decreased PPT than those with unilateral TrP (P<0.01). Our results showed that manual exploration of TrPs in the upper trapezius muscle elicited referred pain patterns in both CTTH patients and healthy subjects. In CTTH patients, the evoked referred pain and its sensory characteristics shared similar patterns as their habitual headache pain, consistent with active TrPs. Our results suggest that spatial summation of perceived pain and mechanical pain sensitivity exists in CTTH patients.
Repair of tympanic membrane perforation using a modified cartilage–perichondrium composite ring graft
Authors: Mansour M H , Askar M H , Albirmawy O A
Published: August 2006

Ring graft is a modified cartilage-perichondrium composite graft (CPCG) with only a peripheral ring shaped cartilage. In this series, tympanic membrane perforations were repaired using (ring graft) during treatment of 18 cases of non-cholesteatomatous chronic suppurative otitis media (CSOM).

This study showed that ring graft has the advantages of both CPCG and perichondrial graft but without their disadvantages. Complete closure of the perforations was achieved in all cases without delay in hearing improvement.

It is recommended to use the ring graft whenever needed to repair central tympanic membrane perforations even with difficult anterior or total perforations.
Thyroid fine needle cytology complicated by recurrent laryngeal nerve palsy and unnecessary radical surgery
Authors: Hulin S J , Harris K P
Published: August 2006

Fine needle aspiration cytology (FNAC) is an important tool in the investigation of thyroid nodules and has few reported complications. We present the first report of recurrent laryngeal nerve palsy arising as a complication of thyroid nodule FNAC. This complication led to inaccurate diagnosis and unnecessarily radical surgery, with consequent increased morbidity.
A clinical review of 128 cases of head and neck tuberculosis presenting over a 10-year period in Bradford, UK
Authors: Menon K , Bem C , Gouldesbrough D , Strachan D R
Published: August 2006

Aims: To analyse the epidemiology, presentation and diagnosis of head and neck tuberculosis (TB).

Methods: We conducted a 10-year retrospective study of all cases of tuberculosis of the head and neck region occurring in Bradford, UK.

Results: Of a total of 1315 cases of TB, 128 presented with head and neck TB (12 per cent of which (15/128) were in children). Cervical lymph nodes were most commonly involved (87 per cent, 111/128), other sites being: salivary glands (five cases); larynx, oral cavity, eyes and ears (two cases each); and skin, thyroid, nasopharynx and retropharyngeal space (one case each). Patients' ethnic origins were Asian (89 per cent, 114/128), Caucasian (10 per cent, 13/128) and African (one case). Only 26 per cent (33/128) had constitutional symptoms, and 20 per cent (25/128) had a coexistent site of TB. Only 39 per cent (40/105) of surgical specimens were sent for culture.

Conclusions: Isolated head and neck TB is not uncommon. Atypical presentations render diagnosis challenging, so awareness aids early diagnosis. Mycobacterial cultures should be performed, where possible, for diagnosis.
The evolution of tonsil surgery and rethinking the surgical approach to obstructive sleep-disordered breathing in children
Authors: Koempel J A , Solares C A , Koltai P J
Published: August 2006

Within the last 10 to 15 years, a significant amount of research in tonsil surgery has focused on reduction of post-operative pain and recovery time. In order to minimize or avoid morbidity, a number of otolaryngologists in the United States and Europe have revived a historical procedure, previously known as ‘tonsillotomy’, specifically for those patients with obstructive sleep-disordered breathing (OSDB) due to adenotonsillar hypertrophy. More recently, surgeons have used terms such as partial tonsillectomy, partial intracapsular tonsillectomy or subtotal tonsillectomy to describe their procedure and have employed a variety of modern instrumentation. This return to a ‘partial’ procedure has generated a debate similar to that which occurred amongst tonsil surgeons about 100 years ago, when tonsillotomy was the most commonly performed procedure. Today, concerns about regrowth and problems with infection of the remaining tonsillar tissue have been raised. Such concerns, combined with an incomplete understanding of why the ‘partial’ procedure was abandoned in the early twentieth century, may explain why tonsil surgeons hesitate to change their approach to patients with OSDB due to adenotonsillar hypertrophy. These issues can be addressed in a meaningful way only through a detailed review of the evolution of tonsil surgery, which is presented here. This information, along with a summary of the last 10 years' experience with these techniques, supports the use of a ‘partial’ procedure in children with OSDB due to adenotonsillar hypertrophy. Future areas of research are also discussed.
Applied comparative physiology of the avian middle ear: the effect of static pressure changes in columellar ears
Authors: Mills R , Zhang J
Published: August 2006

We investigated the motion of the single ossicle found in the middle ears of four different species of birds. In the avian middle ear, the off centre attachment of the extracolumella to the tympanic membrane and the flexion of the joint between the extracolumella and columella results in rocking of the footplate rather than direct excursion in and out of the vestibule. We postulate that this is a protective mechanism to avoid excessive displacement of the footplate into the vestibule during changes in middle-ear pressure and that it is analogous to the ossicular ‘decoupling’ observed in the human middle ear in the same circumstances.
Prevention of postlaryngectomy pharyngocutaneous fistula using a sternocleidomastoid muscle collar flap
Authors: Albirmawy O A
Published: August 2006

Objectives: The purpose of this study was to evaluate the efficacy of a sternocleidomastoid muscle collar flap in the prevention of pharyngocutaneous fistula in patients who had undergone total laryngectomy.

Study design: Retrospective clinical study.

Setting: Otolaryngology department, Tanta University, Egypt.

Methods: Sixty-five consecutive total laryngectomy procedures performed between October 1999 and October 2005 were reviewed. The fistula rate in laryngectomy patients operated on prior to 2002, without sternocleidomastoid collar flap creation (group A) was compared with that of patients operated on after October 2002, at which time this flap was introduced for routine use during primary surgery (group B).

Results: In group A, the incidence of pharyngocutaneous fistula was 12 in 35 (34 per cent) while its incidence in group B was 1 in 30 (3.3 per cent). On analysis, the risk factors within both the groups were essentially similar.

Conclusion: The routine addition of a superiorly based sternal head of sternocleidomastoid muscle flap on one or both sides to cover the repaired pharynx during surgery reduced the incidence of postlaryngectomy pharyngocutaneous fistula, patient morbidity and mortality, and hospital stay; voice rehabilitation and swallowing were also improved.
Large-amplitude electrostatic solitary structures in a charge varying dusty plasma with vortex-like ion distribution
Authors: GOUGAM LEILA AIT , TRIBECHE MOULOUD , MEKIDECHE FAWZIA
Published: August 2006

A numerical investigation is presented to show the existence, formation and possible realization of large-amplitude solitary potentials in a charge varying dusty plasma with trapped ion particles. These nonlinear localized structures are self-consistent solutions of the Vlasov equation representing saturated states of a three-stream unstable collisionless dusty plasma. The saturation is provided by an interplay between ion trapping and dust charging. It is found that under certain conditions the effect of dust charge variation can be quite important. In particular, it may be noted that the dust charge variation leads to an additional enlargement of the nonlinear localized structure. Furthermore, our results show that the dust charge variation provides an alternate physical mechanism causing dissipation and as a consequence causes the wave amplitude to decay and transfer to the so-called noise tail.
Anomalous absorption of the circularly polarized electromagnetic beams near the plasma frequency in a magnetized electron plasma
Authors: SESHADRI S. R.
Published: August 2006

The propagation of circularly polarized electromagnetic beams along the magnetostatic field in an electron plasma is investigated. As a consequence of a strong interaction with the medium, the beam spreads rapidly on propagation near the cutoff frequencies and the cyclotron resonant frequency of the corresponding plane waves, as well as near the plasma frequency. The power absorption for unit length near the cyclotron frequency and the plasma frequency are determined. For tightly focused beams, there is significant power absorption near the plasma frequency as compared with that at the cyclotron resonant frequency.
Photobiont flexibility in the lichen Protoparmeliopsis muralis as revealed by ITS rDNA analyses
Authors: GUZOW-KRZEMIŃSKA Beata
Published: August 2006

The genetic diversity of photobionts in the lichen Protoparmeliopsis muralis was examined to determine the identity of the photobiont and the level of selectivity for the photobiont by the mycobiont. Forty ITS rDNA sequences of photobionts from thirty nine specimens of Protoparmeliopsis muralis have been determined. The photobiont species were identified both by direct comparison with the available sequences and by phylogenetic analysis. The sequences obtained from P. muralis specimens belonged to different Trebouxia clades. The most common photobionts were T. incrustata and an unidentified lineage, here named as “muralis I”. Less common photobionts were T. asymmetrica and T. gigantea. Two unidentified Trebouxia spp. and a photobiont that belonged to the clade that includes T. impressa, T. flava and T. potteri were also found to be associated with P. muralis. Such flexibility has not been reported to date. Moreover, two different photobionts were found in a single specimen. They belonged to the T. gigantea clade and “muralis I” lineage. The low level of selectivity with respect to the photobiont may constitute an important aspect in that Protoparmeliopsis muralis is one of the most successful urban lichens in the world.
Two new Lecanora species from India
Authors: NAYAKA Sanjeeva , UPRETI D. K. , LUMBSCH H. Thorsten
Published: August 2006

The new species, Lecanora luteomarginata and L. subpraesistens, are described from northern India. The first is characterized by apothecia with dark brown discs and bright yellow margins, while L. subpraesistens is a multispored species that is readily distinguished by an egranulose epihymenium and a melacarpella-type amphithecium.
Pertusaria christae is a synonym of P. saximontana
Authors: Zhurbenko Michael P. , Lumbsch H. Thorsten
Published: August 2006

During fieldwork in Siberia and Alaska the senior author has sporadically found an unusual Pertusaria species that was tentatively identified as P. christae Dibben & Poelt. This species has been described from a few localities in the Austrian Alps (Dibben & Poelt 1987) and was recently recorded from the Putorana Plateau in Russia (Zhurbenko 1996). Examination of various herbarium collections confirmed that the species is more widely distributed in the Holarctic, but probably overlooked. Further, its distinction from P. saximontana was unclear. According to the literature, P. saximontana is a corticolous or lignicolous species occurring in North America and containing 2-O-methylconfluentic acid (Dibben 1980; Lumbsch et al. 1999; Wetmore 1967). In contrast, P. christae is regarded as a muscicolous or terricolous Eurasian species containing 2′-O-methylperlatolic acid (Dibben & Poelt 1987). In micromorphological features the two species are very similar, and habitat and chemistry were the main characteristics used to separate the two taxa. In our studies, however, we found 2′-O-methylperlatolic acid in several lignicolous collections from North America, raising the question whether the two species are distinct. Hence, we have studied additional material, including the types of both species to clarify the status of the two described taxa.