bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal control of mechanical systems subjected to periodic loading via chebyshev polynomials
Authors: Joseph Paul , Pandiyan R. , Sinha S. C.
Published: July 2007

Controllers using full‐state feedback and observer‐based feedback for mechanical systems subjected to periodic follower loads are designed in this paper. The designs are accomplished using an algebraic method incorporating Chebyshev polynomials coupled with principles of optimal control theory. The major advantage of this method is that it transforms differential equations with periodic coefficients to linear algebraic equations. Also, a dual‐system approach to design observers for such periodic systems turns out to be a novel technique and appears to have been employed for the first time. As an example of a mechanical system a triple inverted pendulum subjected to a periodic follower load is chosen and it is shown that both types of controllers can be successfully designed. The computational aspects and the suitability of this method for higher‐order mechanical systems are studied by applying it to one through five‐mass inverted pendulum models. The efficiency of the method is checked against the Runge–Kutta, Adams–Moulton and Gear numerical algorithms available in the IMSL software package by comparing the CPU time taken to evaluate the characteristic exponents of the Floquet transition matrix (FTM) as well as the norm of the control vector at the end of one period. It is shown that the proposed technique becomes much more efficient for higher‐order systems.
Decomposition and suboptimal control in dynamic systems
Authors: Chernousko F. L.
Published: July 2007

A non‐linear dynamic system subject to bounded control forces is considered. It is shown that under certain conditions the feedback control can be chosen in such a way that the system reaches the prescribed terminal state in finite time. This control is obtained through decomposition of the system into subsystems with one degree of freedom each and applying the approach of differential games. Explicit formulae for the bounded control forces and the time of motion are presented. The obtained control is robust and can cope with small disturbances and parameter variations. Applications to robot control are discussed. The obtained feedback control is compared with another one which does not take small non‐linearities and disturbances into account.
A multi‐input/multi‐output optimal PI controller for redundant robots in the presence of flexible disturbances
Authors: Barbieri Enrique
Published: July 2007

The two‐stage synthesis of a multi‐input/multi‐output optimal proportional‐integral (PI) controller is described for linear, time‐invariant systems. In the first stage the PI controller is designed by solving a steady state algebraic Riccati equation. As a result, the optimal cost is expressed in terms of the system's constant output set‐points. In the second stage the cost is further reduced by optimally selecting the output set‐points to minimize a static quadratic performance index subject to linear algebraic constraints. The design framework is applied to a planar redundant robotic manipulator equipped with four joints and mounted at the tip of a long flexible arm. We then address the problem of self‐motion control in the presence of vibratory disturbances.
A gradient flow approach to computing lq optimal output feedback gains
Authors: Yan Wei‐Yong , Teo Kok L. , Moore John B.
Published: July 2007

This short communication considers the linear quadratic problem with static output feedback. It is shown that an optimal solution can be successfully computed by finding the limiting solution of an ordinary differential equation which is given in terms of the gradient flow associated with the cost function. Several properties are obtained concerning the gradient flow. For example, it is shown that the flow contains a subsequence convergent to a locally optimal output feedback gain. In the special case of state feedback the flow is guaranteed to converge to the optimal gain. The effectiveness of the method is demonstrated by an example.
Mixed H2/H∞ control with pole placement in a class of regions
Authors: Bambang Riyanto T. , Shimemura Etsujiro , Uchida Kenko
Published: July 2007

The problem of mixed H2/H∞ control with pole placement is considered for linear time‐invariant systems. This is the problem of determining a controller for linear time‐invariant systems which minimizes the H2‐norm of a certain closed‐loop transfor function subject to an H∞‐norm constraint on another closed‐loop transfer function and an additional constraint on the location of the closed‐loop poles in the complex plane. An optimization problem is posed for the pole‐constrained H2/H∞, problem in such a way that the objective function is expressed as a weighted sum of the actual H2 cost and its upper bound. A necessary condition for the optimization problem is derived via the Lagrange multiplier technique. The condition involves a set of highly coupled equations. By sacrificing the H2 performance, an alternative optimization problem is posed in order to simplify the necessary condition. An iterative algorithm for solving the coupled equations arising in the necessary conditions is proposed and numerical examples are presented.
Nonlinear optimal control of washing machine based on approximate solution of HJB equation
Authors: Milasi Rasoul M. , Yazdanpanah Mohammad‐Javad , Lucas Caro
Published: July 2007

Performance of a washing machine depends on different parameters, namely water temperature, degree of soiling, water volume, and motor speed. In this paper, firstly, a nonlinear model is derived based on the empirical data. In addition, validity of the proposed model is also verified. Secondly, to optimize the performance, a quadratic energy function is considered, which is minimized subject to the nonlinear model of the Washing Machine. Finding the corresponding control law requires solving a partial differential equation called Hamiltonian–Jacobi–Bellman (HJB) equation. An approximate solution for HJB equation using the second‐, third‐, and fourth‐order terms of Taylor's series expansion is utilized. Simulation results reveal that the higher‐order controller leads not only to a lower cost function but also to a better performance. Copyright © 2007 John Wiley & Sons, Ltd.
Prenatal diagnosis of a fetus with androgen insensitivity syndrome (AIS)
Authors: Yalinkaya Ahmet , Yayla Murat , Erdemoglu Mahmut
Published: July 2007

Objective The aim of this study is to describe a fetus with androgen insensitivity syndrome diagnosed at mid‐second trimester.

Case and Methods Nuchal translucency was measured thick and double test was found higher. The patient referred to our center at 16th weeks of gestation. Fetal ultrasound examination and amniocentesis was performed.

Results The nuchal translucency (NT) of fetus in present pregnancy was measured approximately 10 mm at 13 weeks and Down syndrome risk was calculated 1 in 10 by double test. On ultrasound examination; thick nuchal fold (NF) and short fetal limbs were found, and the fetus was seen a female and amniocentesis was performed. Three weeks later the fetal karyotype was reported normal as 46,XY. Thereupon the fetus reexamined for 2D and 4D ultrasound, and confirmed previous findings. The fetus was terminated at 19th weeks and seen a female phenotype. The fetal gonads removed in abdomen and testicles confirmed histopatologically.

Conclusion In generally, diagnosis of AIS is most made postnatally. This is the second case in English literature, which diagnosed mid‐second trimester. In this situation, the fetus with thick NT/NF and short limbs may be AIS, therefore appearance of fetal sex on ultrasound should be compared with genetic sex Copyright © 2007 John Wiley & Sons, Ltd.
Distal partial trisomy 1q: report of two cases and a review of the literature
Authors: Utine G. E. , Aktas D. , Alanay Y. , Gücer S. , Tuncbilek E. , Mrasek K. , Liehr T.
Published: July 2007

We report on two cases with partial trisomy 1q syndrome. One case was a mid‐trimester fetus with multiple malformations that was prenatally diagnosed with a de novo distal partial trisomy 1q. Prenatal ultrasound at 24th gestational week demonstrated the presence of cleft lip and palate, increased biparietal diameter and decreased abdominal circumference. Cytogenetic analysis (GTG banding) and subsequent fluorescence in situ hybridization (FISH) using whole chromosome paint 1 and multicolor banding (MCB) demonstrated an aberrant karyotype 46,XY,dup(1)(q31q43∼44). The second case was a newborn male infant with multiple congenital malformations. He had a derivative chromosome 18 as a result of a maternal insertion involving chromosomes 1 and 18. Further analyses including MCB showed his karyotype as 46,XY,ins(18;1)(q22;q23q31.1∼32). The present cases and a review of the literature suggest that partial trisomy of the long arm of chromosome 1 is a distinct clinical entity. Copyright © 2007 John Wiley & Sons, Ltd.
Isolated fetal hydrothorax with hydrops: a systematic review of prenatal treatment options
Authors: Deurloo K. L. , Devlieger R. , Lopriore E. , Klumper F. J. , Oepkes D.
Published: July 2007

Objective To evaluate the effect of prenatal therapeutic interventions on perinatal outcome in pregnancies complicated by isolated fetal hydrothorax with hydrops.

Methods A systematic review of the literature from January 1982 to January 2006 of perinatal outcome in pregnancies with isolated fetal hydrothorax with hydrops with any form of prenatal treatment was conducted.

Results Forty‐four articles met our selection criteria, reporting a total of 172 fetuses treated prenatally. Reported treatment options were single (n = 13) or serial thoracocentesis (n = 18), thoraco‐amniotic shunt placement (n = 100) or a combination of thoracocentesis and shunting (n = 36). Four case‐reports described pleurodesis with OK‐432, (n = 3) and intrapleural injection of autologous blood (n = 2). Overall survival rate was 63%, ranging from 54% for single thoracocentesis to 80% in the 5 cases treated with pleurodesis, without statistically significant differences between the treatment modalities. Shunt‐placement with or without prior thoracocentesis was most often described, with survival rates of 67 and 61% respectively.

Discussion The available literature consists exclusively of case reports and case series. This systematic review suggests that with prenatal intervention, perinatal survival rates around 63% are possible. There is a need for prospective, adequately controlled studies with long‐term follow‐up to determine the best treatment and more reliable outcome data in pregnancies complicated by fetal hydrothorax with hydrops. Copyright © 2007 John Wiley & Sons, Ltd.
Medical therapy for diabetes is associated with increased use of lower endoscopy
Authors: Lewis James D. , Capra Angela M. , Achacoso Ninah S. , Ferrara Assiamira , Levin Theodore R. , Quesenberry Charles P. , Habel Laurel A.
Published: July 2007

Background

Diabetes mellitus is associated with an increased risk of colorectal neoplasia and diabetes medications may further influence the risk. Observational studies of the effect of diabetes medications on colonic neoplasia may be biased if use of diabetes medications is associated with undergoing lower endoscopy. This study examined the association between diabetes therapies and use of lower endoscopy.

Methods

This retrospective cohort study included patients with diabetes in an integrated, prepaid health plan. The primary exposure variables were use of sulfonylureas, metformin, thiazolidinediones (TZDs), and insulin. The outcome measure was completion of a flexible sigmoidoscopy or colonoscopy. Cox proportional hazards modeling, accounting for the time‐varying nature of the medication exposures, was used to generate estimates of the relative hazard (HR) of lower endoscopy with different medications.

Results

The study included 44 169 patients followed for a mean duration of 4.2 years (SD = 2.5 years); 34% underwent at least one lower endoscopy. Patients who filled a diabetes medication prescription were more likely to undergo lower endoscopy (HR = 1.13, 95%CI 1.06–1.21). Compared to those taking only sulfonylureas, patients receiving sulfonylureas and metformin (HR = 1.12, 95%CI 1.06–1.18) or metformin alone (HR = 1.17, 95%CI 1.07–1.26) were more likely to undergo lower endoscopy. For all medications, new use was associated with undergoing lower endoscopy (p < 0.05 for all comparisons).

Conclusions

Diabetic patients receiving medications are more likely to undergo lower endoscopy than those on diet control alone, particularly in the first year after initiating a new medication class and if taking metformin. Copyright © 2007 John Wiley & Sons, Ltd.
Insight into chain dimensions in PEO/water solutions
Authors: Hammouda Boualem , Ho Derek L.
Published: July 2007

Small‐Angle Neutron Scattering has been performed from poly(ethylene oxide) in deuterated water at temperature ranging from 10 to 80 °C. A simple fitting model was used to obtain a correlation length and a Porod exponent. The correlation length L characterizes the average distance between entanglements in the semidilute region and is proportional to the individual coil sizes in the dilute region. L was found to increase with temperature in the semidilute region but it decreases with temperature in the dilute region. This decrease is the precursor to the single‐chain collapse which applies to very dilute polymer solutions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2196–2200, 2007
Protein–thiol substitution or protein dethiolation by thiol/disulfide exchange reactions: The albumin model
Authors: Summa Domenico , Spiga Ottavia , Bernini Andrea , Venditti Vincenzo , Priora Raffaella , Frosali Simona , Margaritis Antonios , Giuseppe Danila Di , Niccolai Neri , Simplicio Paolo Di
Published: July 2007

Dethiolation experiments of thiolated albumin with thionitrobenzoic acid and thiols (glutathione, cysteine, homocysteine) were carried out to understand the role of albumin in plasma distribution of thiols and disulfide species by thiol/disulfide (SH/SS) exchange reactions. During these experiments we observed that thiolated albumin underwent thiol substitution (Alb‐SS‐X+RSH↔Alb‐SS‐R+XSH) or dethiolation (Alb‐SS‐X+XSH↔Alb‐SH+XSSX), depending on the different pKa values of thiols involved in protein–thiol mixed disulfides (Alb‐SS‐X). It appeared in these reactions that the compound with lower pKa in mixed disulfide was a good leaving group and that the pKa differences dictated the kind of reaction (substitution or dethiolation). Thionitrobenzoic acid, bound to albumin by mixed disulfide (Alb‐TNB), underwent rapid substitution after thiol addition, forming the corresponding Alb‐SS‐X (peaks at 0.25–1 min). In turn, Alb‐SS‐X were dethiolated by the excess nonprotein SH groups because of the lower pKa value in mixed disulfide with respect to that of other thiols. Dethiolation of Alb‐SS‐X was accompanied by formation of XSSX and Alb‐SH up to equilibrium levels at 35 min, which were different for each thiol. Structures by molecular simulation of thiolated albumin, carried out for understanding the role of sulfur exposure in mixed disulfides in dethiolation process, evidenced that the sulfur exposure is important for the rate but not for determining the kind of reaction (substitution or dethiolation). Our data underline the contribution of SH/SS exchanges to determine levels of various thiols as reduced and oxidized species in human plasma. © 2007 Wiley‐Liss, Inc.
Taro Colocasia esculenta (L.) Schott Amylopectin Structure and Its Effect on Starch Functional Properties
Authors: Tattiyakul Jirarat , Pradipasena Pasawadee , Asavasaksakul Sukruedee
Published: July 2007

Flour extracted from small‐, medium‐, and large‐corm taro Colocasia esculenta (L.) Schott cultivated in central Thailand had similar proximate composition, comparable calcium oxalate and amylose content, but different starch granule size and average chain length of amylopectin. Starch from the larger corm taro had a smaller average granule size and a lower average amylopectin chain length (CLavg), a lower average external chain length (ECLavg), and a lower average internal chain length (ICLavg) when compared to that from the smaller corm taro. The solubility of taro starch was inversely proportional to CLavg, ECLavg, and ICLavg. Starch having a shorter CLavg, ECLavg, and ICLavg had a higher peak viscosity and breakdown. The onset (To), peak (Tp), and conclusion temperatures (Tc) of starch gelatinization and the extent of starch paste retrogradation did not correlate with the amylopectin structure.
Development of optimization methods for improvement of electromagnetic devices
Authors: Korovkin N. V. , Chechurin V. L. , Hayakawa M.
Published: July 2007

This paper presents a brief review of the inverse problems in electrical circuits and electromagnetic theory in our recent monograph. Statements and features of inverse problems in electrical engineering are considered, and different approaches to the solution of multicriterion optimization problems are compared. The main emphasis is on the problems of the application of discrete and continuous Lagrange multiplier methods to solve the optimization problems in the electric circuit theory and electromagnetic field theory. It is shown that the effectiveness of the application of the Lagrange method is related to the calculation of the gradient of the function under minimization with the computation of variables conjugate to the initial ones. A few examples of this kind of optimization problems in electrical engineering are presented. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Smooth switching control for transfer from the Automatic Traveling Mode to the Power Assist Mode of the Skill‐Assist
Authors: Lee Suwoong , Yoon Seong‐Sik , Hara Susumu , Yamada Yoji
Published: July 2007

The objective of this study is to verify a smooth switching control method for transfer from the automatic traveling mode (ATM) to the power assist mode (PAM) of Skill‐Assist. A control law including time‐varying impedance parameters is utilized to attain the objective. The experimental result shows that the transfer from ATM to PAM was successfully performed by the smooth switching control method. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Uptake of microcystins‐LR and ‐LF (cyanobacterial toxins) in seedlings of several important agricultural plant species and the correlation with cellular damage (lipid peroxidation)
Authors: Peuthert Anja , Chakrabarti Shumon , Pflugmacher Stephan
Published: July 2007

Plants used for agriculture may come into contact with cyanobacterial toxins via spray irrigation when surface water bodies containing cyanobacteria are used as the water source. As many of the bloom forming cyanobacteria are known to produce a variety of toxins, the possibility of uptake of toxins in these plants seems possible. With this study the uptake of two microcystins (MC‐LR and MC‐LF) as well as MC‐LR within a cyanobacterial crude extract in several important agricultural plants is presented. Especially high uptake values in roots of alfalfa and wheat, using an ELISA kit for microcystin detection, is shown. In general, concentrations in the shoot occur at a much lower level than in the root. The amount of toxin is correlated with cellular damage in the seedlings using lipid peroxidation as an indicator. Good correlation was shown between toxin uptake and lipid peroxidation in the seedlings. The exposure of agriculturally important crop plants to cyanobacterial toxins via spray irrigation or watering is a potential concern for human health, as these toxins may accumulate in plant tissues and may therefore be carried through the food chain. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 436–442, 2007.
Histopathological gill changes in wild leaping grey mullet (Liza saliens) from the Esmoriz‐Paramos coastal lagoon, Portugal
Authors: Fernandes Conceição , Fontaínhas‐Fernandes António , Monteiro Sandra Mariza , Salgado Maria Antónia
Published: July 2007

The histopathological changes are among the most recognized responses to environmental stressors, namely heavy metals. Liza saliens were sampled, in the Portuguese Esmoriz‐Paramos coastal lagoon to assess their gill histopathological response to Cu and Zn contaminated sediments. A lesion prevalence index, severity, and extension scores of each lesion, as well as an assessment value (severity × extension), were determined to evaluate the effect of environmental heavy metal exposure. The main histopathological changes observed were aneurisms, hyperplasia, lifting, and vasodilation. A high prevalence for each lesion (65–85%) was found, in addition to a high number of simultaneous lesions. Vasodilation and hyperplasia were the lesions that showed higher prevalence indexes. Lifting, followed by hyperplasia, were the lesions with highest assessment value. The prevalence of the number of the lesions found in L. saliens collected from the Esmoriz‐Paramos lagoon was high when compared with mullet caught in the sea. A previous work revealed that fish collected in the lagoon showed elevated Cu and Zn levels in their gills, in a positive correlation with age. However, no positive correlation was observed between assessment value and gill metal levels. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 443–448, 2007.
Comparative study of pathological lesions induced by multiwalled carbon nanotubes in lungs of mice by intratracheal instillation and inhalation
Authors: Li Jun‐Gang , Li Wen‐Xin , Xu Jing‐Ying , Cai Xiao‐Qing , Liu Rui‐Li , Li Yong‐Jun , Zhao Qun‐Fen , Li Qing‐Nuan
Published: July 2007

The pathological lesions induced by multiwalled carbon nanotubes (MWCNTs) in bronchi and alveoli of mice were studied by intratracheal instillation and inhalation. In instillation groups, the dose was 0.05 mg MWCNTs/mouse. Similar size clumps of MWCNTs were distributed in bronchi and alveoli. The clumps led to inflammation to the lining wall of bronchi and severe destruction to alveolar netted structure around them. In the inhalation groups, the mice were exposed to aerosolized MWCNTs with mean concentration of 32.61 mg/m3, the intralung deposition dose were roughly 0.07, 0.14, and 0.21 mg in the 8‐day group, 16‐day group, and 24‐day group, respectively. Most of aggregations of MWCNTs in the alveoli were smaller than that in bronchi. The aggregations induced proliferation and thickening of alveolar walls. With the exception of these moderate pathological lesions, the general alveolar structure was still remained. The preliminary study demonstrated a difference in lung pathological lesions induced by instilled MWCNTs and inhaled ones, which may be due to the different size and distribution of aggregations of MWCNTs in lung. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 415–421, 2007.
Cadmium induced oxidative stress influence on glutathione metabolic genes of Camellia sinensis (L.) O. Kuntze
Authors: Mohanpuria Prashant , Rana Nisha K. , Yadav Sudesh Kumar
Published: July 2007

Glutathione, a tripeptide with sulfhydryl (‐SH) group is a very crucial compound primarily involved in redox balance maintenance of the cellular environment. In this study, we monitored the influence of Cd exposure on the transcript levels of glutathione metabolic genes in bud tissues, the youngest leaf, of Camellia sinensis L. In addition, some physiochemical parameters were also studied. Cd exposure decreased chlorophyll and protein contents, while increase was observed in lipid peroxidation upon Cd treatments. These changes were found to be concentration and duration dependent, indicating the occurrence of oxidative stress upon Cd exposure. The transcript levels of glutathione biosynthetic genes viz. γ‐glutamylcysteine synthetase (γ‐ECS) and glutathione synthetase (GSHS) increased upon Cd exposure. Furthermore, transcript levels of glutathione reductase (GR), an enzyme involved in reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH), also showed upregulation on Cd exposure. However, the transcript levels of glutathione‐S‐transferase (GST), an enzyme involved in forming metal–GSH complex and help in sequestration of high levels of metal ions to vacuole, did not show any change on Cd treatment. This study document that Cd exposure induces oxidative stress in Camellia sinensis and the upregulation in transcript levels of glutathione metabolic genes except GST have suggested the role of these enzymes in the protection of plants from high level Cd exposure. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 368–374, 2007.
Effects of co‐culture of amoebae with indoor microbes on their cytotoxic and proinflammatory potential
Authors: Yli‐Pirilä Terhi , Huttunen Kati , Nevalainen Aino , Seuri Markku , Hirvonen Maija‐Riitta
Published: July 2007

Free‐living amoebae are ubiquitous environmental protozoa found in both natural and man‐made environments, including moisture‐damaged buildings. Furthermore, the interaction between amoebae and bacteria has been shown to enhance the virulence and pathogenicity of some bacteria. While the inhabitants of moisture damaged buildings are known to be at risk of suffering adverse health effects, the exact causative agents and mechanisms are still obscure. To examine the possible role of amoebae in the health effects associated with moisture damages, the effects of amoebae on the cytotoxicity and proinflammatory potential of nonpathogenic microbes common in moisture‐damaged buildings were investigated. First, two bacterial and three fungal strains were cultured both individually and in coculture with Acanthamoeba polyphaga. Then, mouse RAW264.7 macrophages were exposed to the cocultures as well as the individually grown bacteria, fungi, and amoebae. Finally, cell viability and production of proinflammatory mediators, i.e., nitric oxide (NO), tumor necrosis factor α (TNF‐α), and interleukin 6 (IL‐6), were measured in macrophages after the exposure. The results revealed that cocultivation with amoebae increased the cytotoxicity of the bacterium Streptomyces californicus and the fungus Penicillium spinulosum. Moreover, the macrophages produced up to 10 times higher concentrations of NO after the exposure to these cocultures than after the exposure to individually grown microbes. Finally, the production of the cytokines was up to two orders of magnitude higher (IL‐6) and up to four times higher (TNF‐α) after exposure to the cocultures when compared to individually grown microbes. We conclude that amoebae are able to potentiate the cytotoxicity and proinflammatory properties of certain microbes associated with moisture damages. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 357–367, 2007.
A new morphospecies of Microcystis sp. forming bloom in the Cheffia dam (Algeria): Seasonal variation of microcystin concentrations in raw water and their removal in a full‐scale treatment plant
Authors: Nasri Hichèm , Bouaïcha Noureddine , Harche Merieme Kaid
Published: July 2007

Toxic cyanobacterial blooms are an increasing problem in Algeria. The production of cyanotoxins (microcystins) and their presence in drinking water represent growing hazards to human health. In this study, seasonal variations in the concentrations of total microcystins and physicochemical parameters (pH, temperature, dissolved oxygen, nitrate, orthophosphate, and chlorophyll‐a) were analyzed in the Cheffia dam (Algeria), mainly used to supply drinking water. The removal of cyanobacterial cells and microcystins was also evaluated in full‐scale plant associated with the Cheffia reservoir. The levels of microcystins (MCYSTs) in both raw and drinking water were evaluated using the protein phosphatase type 2A (PP2A) inhibition test as MCYST‐LR equivalents. Identification of microcystin variants was achieved by LC/MS/MS. During the period of study (March–December 2004), microscopic observation showed the dominance in the autumn months (September–November) of a new morphospecies of Microcystis sp. The MCYST‐LR equivalent concentrations in raw water varied between 50.8 and 28,886 ng L−1. The highest level of toxins was observed in October 2004 and was significantly correlated with the chlorophyll‐a. Three variants of microcystins assigned as microcystin‐YR (MCYST‐YR), microcystin‐LR (MCYST‐LR), and 6Z‐Adda stereoisomer of MCYST‐LR were observed in the crude extract of the Microcystis sp. bloom sample. During the bloom period, total elimination of Microcystis sp. and toxins were achieved through a classical treatment plant comprised of coagulation and flocculation, powdered activated carbon at 15 mg L−1, slow sand filtration and chlorination before storage. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 347–356, 2007.
Transperineal three‐dimensional ultrasound in evaluating anal sphincter muscles
Authors: Lee J. H. , Pretorius D. H. , Weinstein M. , Guaderrama N. M. , Nager C. W. , Mittal R. K.
Published: July 2007

Objectives To evaluate whether transperineal three‐dimensional (3D) ultrasound can be used to depict normal anal sphincter anatomy and to measure the thickness of muscle layers and the anteroposterior length of the levator hiatus.

Methods The study included 22 normal nulliparous female volunteers. Transperineal 3D sonographic evaluation of the anal canal included assessment of sphincter shape, echogenicity, marginal definition and muscle thickness. Measurements of the thickness of the internal anal sphincter (IAS) and puborectalis muscle (PRM) were determined with the women at rest and during squeezing by two observers, and interobserver reliability was determined. The anteroposterior length of the levator hiatus at rest and during squeezing was measured.

Results The proximal end of the anal canal (towards the rectum) consisted of overlapping IAS and PRM, and the distal end (towards the anus) consisted of overlapping IAS and external anal sphincter (EAS). At the PRM level, the mean ± SD IAS thickness was 2.3 ± 0.5 mm at rest and 2.5 ± 0.4 mm during squeezing, and at the mid‐EAS level it was 2.9 ± 0.5 mm at rest and 2.8 ± 0.5 mm during squeezing. The PRM thickness was 6.5 ± 1.0 mm at rest and 6.4 ± 1.2 mm during squeezing. The difference in muscle thickness of the sphincter layers with the woman at rest and during squeezing was not significant. The anteroposterior length of the levator hiatus was 51.7 ± 5.0 mm at rest and 47.4 ± 4.1 mm during squeezing (P < 0.01).

Conclusion Transperineal 3D ultrasound may be useful in evaluating the anatomy of the anal canal. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Transients in collection grids of large offshore wind parks
Authors: Liljestrand Lars , Sannino Ambra , Breder Henrik , Thorburn Stefan
Published: July 2007

In this paper, transients that can occur in collection grids of large offshore wind parks (WPs) are investigated. Issues concerning modeling of components, such as cables and circuit breakers, for transient studies are discussed. A WP including 80 wind turbines for a total rated power of 160MW is simulated with PSCAD/EMTDC (Manitoba HVDC Research Centre, Winnipeg, Manitoba, Canada). Examples of transient events occurring in the WP are presented. Both switching operations in normal conditions, such as energizing feeders, and faults are considered. Copyright © 2007 John Wiley & Sons, Ltd.
Using evaluation to improve program quality based on the BELL model
Authors: Phalen Earl Martin , Cooper Tiffany M.
Published: July 2007

Building Educated Leaders for Life (BELL) is a national not‐for‐profit organization whose mission is to increase the educational achievements, self‐esteem, and life opportunities of elementary school children living in low‐income urban communities. BELL has been engaged in formal evaluation, internally and externally, for more than five years and has built internal evaluation capacity by investing in a specialized full‐time evaluation team. As part of a continuous program improvement model of evaluation, BELL uses the data to refine program implementation and replicate successful elements of the services and operations. In this chapter, the authors highlight best practices from the field by outlining BELL's approach to using evaluation data for continuous program improvement. Key strategies include (1) carefully identifying intended users of the evaluation throughout the organization and among its external stakeholders, then working closely with intended users throughout the evaluation process, ensuring full engagement at every step of the process; (2) reporting findings in a readable, user‐friendly format and timing the reporting so that it is aligned with programmatic decision making and planning cycles; and (3) making and supporting explicit recommendations for the next program cycle, where intended users have agreed to recommendations and ownership is assigned. BELL's successful use of data for improvement is evidenced by the consistently strong outcomes for the students it serves as well as increased efficiency and satisfaction related to service delivery that has supported the replication of BELL's programs nationally.
How Do Relationships Support Parenting? Effects of Attachment Style and Social Support on Parenting Behavior in an At‐Risk Population
Authors: Green Beth L. , Furrer Carrie , McAllister Carol
Published: July 2007

The importance of supportive relationships for new parents has been the focus of both research and parenting interventions. Attachment style, typically viewed as a relatively stable trait reflecting one's comfort in social relationships, as well as social support, or one's perception of the social context, have both been found to be important for fostering engaged, involved parenting. Less is known, however, about how these variables work together to influence parenting behavior, especially in families at higher risk for negative child outcomes. Data were collected from 152 urban, predominantly African American, low‐income parents when their children were 14 and 36 months of age. Results suggest that parents with more social support show greater increases in the frequency of positive parent–child activities over time, but that this effect is mediated by mothers’ attachment style, specifically, their level of anxious/ambivalent attachment. Mothers with more social support tended to be less anxious/ambivalent about close relationships, and this in turn led to increases over time in the frequency of parent–child interactions. Mothers’ tendency to avoid close relationships, however, while correlated with social support, was unrelated to changes in parenting behavior. Implications of these findings for program development, parenting, and the malleability of attachment style based on social context are discussed.
Streblid bat fly assemblage structure on Paraguayan Noctilio leporinus (Chiroptera: Noctilionidae): nestedness and species co-occurrence
Authors: Presley Steven J.
Published: July 2007

Evaluation of proximate mechanisms (e.g. dispersal, immigration, competition, facilitation) that determine patterns of assemblage or community structure is an important step in the development of paradigms in ecology. Host–parasite systems are useful for such studies because host-parasite assemblages are easily defined units of study, each host individual harbours a sample from a community or assemblage, and many host species are common, providing replicate samples. I used ectoparasite assemblages from Noctilio leporinus collected from Paraguay to evaluate effects of host sex and body size on ectoparasite abundance and to determine if these assemblages exhibit a nested pattern of species co-occurrence. A total of 533 ectoparasites representing seven species and four families were collected from 28 hosts. Abundances of Paradyschiria fusca and Noctiliostrebla aitkeni responded positively to host body size. Host sex had no affect on ectoparasite abundances. Streblid bat fly assemblages from Noctilio leporinus were strongly and significantly nested. Abundances of all species of streblid were positively correlated with one another with Pearson product moment correlation coefficients between 0.424 and 0.646. Competition does not appear to affect community structure of streblids from Paraguayan Noctilio leporinus. Independent responses of species of streblid to host characteristics appear to mould assemblage structure in this system.
Disyllabic attractors and anti-antigemination in Austronesian sound change
Authors: Blust Robert
Published: July 2007

An overview of the historical phonology of the Austronesian languages shows certain recurrent patterns of change that resemble the synchronic notion of a conspiracy. Over 90% of all lexical bases in Proto-Austronesian and other early Austronesian proto-languages are disyllabic. This dominant pattern, which was transmitted to most of the 1200-plus Austronesian languages spoken today, has tended repeatedly to reassert itself in forms that have come to have other than two syllables. As a structurally defined target that is satisfied by diverse historical changes, this preferential disyllabism can be considered an ‘attractor’ in the sense of Kelso (1995). Perhaps the most interesting consequence of disyllabic attractors in Austronesian historical phonology is the widespread occurrence of syncope only between identical consonants, a pattern that Odden (1988) has characterised in synchronic systems as one of ‘anti-antigemination’.
From hiatus to diphthong: the evolution of vowel sequences in Romance
Authors: Chitoran Ioana , Hualde José Ignacio
Published: July 2007

Romance languages show hiatus and diphthongal realisations of inheritediVsequences of rising sonority (e.g.ia). We study five Romance varieties with different degrees of contrast between the two realisation types: Romanian, with a diphthong–hiatus contrast, Spanish, with a weaker contrast, French, with no contrast (all diphthongs), and European and Brazilian Portuguese, with no contrast (all hiatus). We show that the different degrees of synchronic contrast are related to three independent factors: (i) a general articulatory tendency for [iV] hiatus to resolve to diphthongs, due to the relative stability of diphthongal articulations; (ii) a structural ‘attractor’ effect of pre-existing [jV] diphthongs in a language, from different historical sources; and (iii) prosodic lengthening effects which inhibit the shift from hiatus to diphthong, supported by phonetic studies of durational patterns across the five languages.
Feedback and regularity in the lexicon
Authors: Wedel Andrew B.
Published: July 2007

Phonologies are characterised by regularity, from the stereotyped phonetic characteristics of allophones to the contextually conditioned alternations between them. Most models of grammar account for regularity by hypothesising that there is only a limited set of symbols for expressing underlying forms, and that an independent grammar algorithm transforms symbol sequences into an output representation. However, this explanation for regularity is called into question by research which suggests that the mental lexicon records rich phonetic detail that directly informs production. Given evidence for biases favouring previously experienced forms at many levels of production and perception, I argue that positive feedback within a richly detailed lexicon can produce regularity over many cycles of production and perception. Using simulation as a tool, I show that under the influence of positive feedback, gradient biases in usage can convert an initially gradient and variable distribution of lexical behaviours into a more categorical and simpler pattern.
Salmonella-induced enteritis: molecular pathogenesis and therapeutic implications
Authors: Layton Abigail N. , Galyov Edouard E.
Published: July 2007

Salmonella-induced enteritis is a gastrointestinal disease that causes major economic and welfare problems throughout the world. Although the infection is generally self-limiting, subgroups of the population such as immunocompromised individuals, the young and the elderly are susceptible to developing more severe systemic infections. The emergence of widespread antibiotic resistance and the lack of a suitable vaccine against enteritis-causingSalmonellahave led to a search for alternative therapeutic strategies. This review focuses on howSalmonellainduces enteritis at the molecular level in terms of bacterial factors, such as the type III secretion systems used to inject a subset of bacterial proteins into host cells, and host factors, such as Toll-like receptors and cytokines. The type III secreted bacterial proteins elicit a variety of responses in host cells that contribute to enteritis. Cytokines form part of the host defence mechanism, but in combination with bacterial factors can contribute toSalmonella-induced enteritis. We also discuss animal and cell culture models currently used to studySalmonella-induced enteritis, and how understanding the mechanisms of the disease has impacted on the development ofSalmonellatherapeutics.
Does the Danube exist? Versions of reality given by various regional climate models and climatological data sets
Authors: Lucarini Valerio , Danihlik Robert , Kriegerova Ida , Speranza Antonio
Published: July 2007

We present an auditing (intercomparison and verification) of several regional climate models (RCMs) nested into the same run of the same atmospheric global circulation model (AGCM) regarding their representation of the statistical properties of the hydrological balance of the Danube river basin for 1961–1990. We also consider the data sets produced by the driving AGCM, by the European Centre for Medium‐Range Weather Forecasts (ECMWF) and National Centers for Environmental Prediction (NCEP)–National Center for Atmospheric Research (NCAR) reanalyses. The hydrological balance is computed by integrating the precipitation and evaporation fields over the area of interest. Large discrepancies exist among RCMs for the monthly climatology as well as for the mean and variability of the annual balances, and only few data sets are consistent with the observed discharge values of the Danube at its Delta, even if the driving AGCM provides itself an excellent estimate. We find consistently that, for a given model, increases in the resolution do not alter the net water balance, while speeding up the hydrological cycle through the enhancement of both precipitation and evaporation by the same amount. Since the considered approach relies on the mass conservation principle and bypasses the details of the air‐land interface modeling, we propose that the atmospheric components of RCMs still face difficulties in representing the water balance even on a relatively large scale. Their reliability on smaller river basins may be even more problematic. Moreover, since for some models the hydrological balance estimates obtained with the runoff fields do not agree with those obtained via precipitation and evaporation, some deficiencies of the land models are also apparent. The driving AGCM greatly overperforms the NCEP‐NCAR and ECMWF 40‐year (ERA‐40) reanalyses, which result to be largely inadequate for representing the hydrology of the Danube river basin, both for the reconstruction of the long‐term averages and of the seasonal cycle. The reanalyses cannot in any sense be used as verification. We suggest that these results should be carefully considered in the perspective of auditing climate models and assessing their ability to simulate future climate changes.
Automatic scaling of critical frequency foF2 and MUF(3000)F2: A comparison between Autoscala and ARTIST 4.5 on Rome data
Authors: Pezzopane Michael , Scotto Carlo
Published: July 2007

The performances of Autoscala and ARTIST 4.5 were comparatively evaluated using a large database of 6098 ionograms recorded from September 2005 to June 2006 by the digisonde DPS4 at the Rome ionospheric station. Results of comparisons between automatically and manually scaled data are shown for both programs highlighting the different behaviors. The Autoscala and ARTIST 4.5 values of foF2 and MUF(3000)F2 both agree with the hand‐scaled values for ∼95% of ionograms. For the other ∼5% of ionograms, which the manual scaler classed as unscalable, ARTIST 4.5 usually gave invalid results, whereas Autoscala usually gave no result. The data recorded by the ionosondes DPS4 (interpreted by ARTIST 4.5) and AIS‐INGV (interpreted by Autoscala) during three geomagnetic storms were also analyzed. Ionograms with typical errors both for Autoscala and ARTIST 4.5 are displayed.
Long term friction: From stick‐slip to stable sliding
Authors: Voisin Christophe , Renard François , Grasso Jean‐Robert
Published: July 2007

We have devised an original laboratory experiment where we investigate the frictional behaviour of a single crystal salt slider over a large number of deformation cycles. Because of its physical properties, salt, an analogue for natural faults, allows for frictional processes plastic deformation and pressure solution creep to operate on the same timescale. During the same experiment, we observe a continuous change of the frictional behaviour of the slider under constant conditions of stiffness, temperature and loading velocity. The stick‐slip regime is progressively vanishing, eventually reaching the stable sliding regime. Concomitantly, the contact interface, observed under the microscope, develops a striated morphology with contact asperities increase in length and width, arguing for an increase in the critical slip distance dc. Complementary experiments including velocity jumps show that the frictional parameters of the rate and state friction law, a and b, progressively vanish with accumulated slip. The ultimate stage of friction is therefore rate and state independent under our experimental conditions.
North American 1818–1824 drought and 1825–1840 pluvial and their possible relation to the atmospheric circulation
Authors: van der Schrier G. , Barkmeijer J.
Published: July 2007

This study aims to test the hypothesis that persistently negative and positive phases of the Pacific‐North American (PNA) atmospheric circulation pattern for the December–March period are responsible for explaining the North American 1818–1824 summer drought and the 1825–1840 summer pluvial, respectively. In this view, reduced or enhanced soil moisture in winter and early spring may perpetuate dry or wet summer conditions, respectively. For these sensitivity simulations, an ocean‐atmosphere coupled climate model of intermediate complexity is used. Rough reconstructions of stream function at 500 hPa over the North Pacific sector averaged over 1818–1824 and 1825–1840 for December–March are assimilated in this model, using a recently developed technique. This technique ensures that in an averaged sense, the reconstructed pattern is retrieved while leaving atmospheric and climatic variability to develop freely. Tree‐ring‐based Palmer Drought Severity Index (PDSI) reconstructions for these periods show many similarities with the numerical experiments, indicating that the simulation of the hydrological aspect of climate in the Pacific‐North American sector is consistent with the available reconstructions, despite the simplified nature of the model and the approach. The simulations show that as a drought is set up in winter and early spring, evaporation decreases and moisture availability in the soils decrease, leading to heat waves which perpetuate the drought into the summer season. Wet conditions are perpetuated from the winter/early spring into summer by a reorganization of atmospheric circulation over the contiguous United States, increasing northward transport of maritime subtropical air from the Gulf of Mexico into the Great Plains region.