bluuebunny/crossref_metadata_2025 huggingface dataset:
Hauptbahnhof Dresden – Instandsetzung und Umbau der Bahnsteighallen
Authors: Vitzthum Michael , Voland Peter , Foster & Partners
Published: March 2006

Die Sanierung der Bahnsteighallen des historischen Dresdner Hauptbahnhofes ist aufgrund der Größe des neuen Membrandaches als Projekt Bauen im Bestand unter laufendem Betrieb einzigartig. Der Entwurf des Architekten Lord Norman Foster beinhaltet die Eindeckung der rund 30000 m2 Dachfläche der gesamten Bahnsteighallen mit einer PTFE‐beschichteten Glasfaserhaut, wobei das vorhandene Eisentragwerk saniert und ertüchtigt wird. Eine der schwierigsten ingenieurtechnischen Herausforderungen bestand darin, die Lasten des neuen Membrandaches in das historische Stahltragwerk ein‐ und in die Fundamente abzuleiten. Die Erneuerung der Hallendächer sowie der im Zusammenhang stehenden Metallfassaden erfolgte dabei mit dem Grundsatz, authentische Elemente zu erhalten und instand zu setzen. Für die Bereiche, in denen die ursprüngliche Gestaltung nicht mehr vorhanden war, wurden zeitgemäße Lösungen gewählt, die dem Charakter der Bahnsteighallen gerecht werden. Es entsteht somit ein Gesamtkonzept, das den Bestand und die Geschichte des Bahnhofes respektiert und bestärkt, aber auch aktuelle und zukunftsweisende Konzeptionen einbringt und die Entwicklung der Bahn repräsentiert (Bild 1).
Comparison between three‐dimensional placental volume at 12 weeks and uterine artery impedance/notching at 22 weeks in screening for pregnancy‐induced hypertension, pre‐eclampsia and fetal growth restriction in a low‐risk population
Authors: Hafner E. , Metzenbauer M. , Höfinger D. , Stonek F. , Schuchter K. , Waldhör T. , Philipp K.
Published: March 2006

Objectives

To compare the value of three‐dimensional placental volume at 12 weeks and uterine artery Doppler at 22 weeks for predicting pregnancy‐induced hypertension (PIH), pre‐eclampsia and fetal growth restriction in a low‐risk population.

Methods

Over a 20‐month period we calculated the placental quotient (PQ = placental volume/crown–rump length) at 11–13 weeks' gestation in all women with singleton pregnancies who booked for delivery in our hospital. At 22 weeks, in the same population, we calculated the mean pulsatility index (PI) of both uterine arteries and the presence of an early diastolic notch was noted. Logistic regression models, the PQ and Doppler parameters were used to compare the two screening methods for subgroups of pregnancy outcome.

Results

Complete outcome data were obtained in 2489 consecutive singleton pregnancies. Logistic regression models for the detection of pre‐eclampsia had a sensitivity of 38.5% (PQ) vs. 44.8% (Doppler); for the detection of small‐for‐gestational age (SGA) the sensitivity was 27.1% (PQ) vs. 28.1% (Doppler) at a specificity of 90%. Taking a PQ of ≤ 10th centile, a mean uterine PI of ≥ 90th centile and a bilateral notch, the sensitivity for detection of SGA was 25.0%, 20.2% and 22.0%, respectively; for PIH it was 9.5%, 4.8% and 4.8%; for pre‐eclampsia without SGA it was 20.0%, 28%, 12%; for PIH/pre‐eclampsia with SGA it was 30.8%, 46.1% and 69.2%. In the group with the most severe complications, in which delivery took place before 34 weeks, the sensitivity was 50.0%, 50.0% and 38.9%, respectively.

Conclusions

PQ at 12 weeks and uterine artery Doppler at 22 weeks have similar sensitivities for predicting pre‐eclampsia and fetal growth restriction, although uterine artery Doppler is marginally more sensitive for the prediction of pre‐eclampsia. While both methods are insufficient for screening in a low‐risk population, the PQ method has the potential advantage of being performed in the first trimester. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Comparison of transvaginal sonography in recumbent and standing maternal positions to predict spontaneous preterm birth in singleton and twin pregnancies
Authors: Arabin B. , Roos C. , Kollen B. , van Eyck J.
Published: March 2006

Objective

To evaluate whether serial transvaginal sonographic examination of the cervix with the woman in a standing position improves the prediction of spontaneous preterm birth (SPB) compared with the conventional posture.

Methods

For both a recumbent and upright maternal position, the inter‐ and intraobserver agreement of cervical length (CL) measurement was calculated. In 363 pregnancies at risk for SPB, we determined prospectively CL and funnel width (FW) including differences between the positions and between longitudinal measurements from 15 weeks onwards. Multivariate logistic regression analysis, contingency tables and receiver–operating characteristics (ROC) curves were used. Data were stratified according to singleton or twin pregnancy, maternal position, gestational age at examination and different cut‐off values to predict SPB < 36 weeks.

Results

The interobserver variability in each position was similar, with an interclass correlation coefficient (95% CI) of 0.952 (0.811–0.984) in the recumbent and 0.942 (0.837–0.978) in the upright maternal position. After exclusion of pregnancies with iatrogenic preterm birth, 15/138 (11%) singletons and 29/153 (19%) twin pairs were born at <36 weeks. The incidence of funneling was greater in an upright compared with a recumbent maternal position by 12.3% in singleton and 13.1% in twin pregnancies before 25 weeks, and by 13.0% and 21.6% between 25 and 30 weeks, respectively. This resulted in an earlier and more accurate prediction of SPB by transvaginal ultrasound in an upright compared with a recumbent maternal position, which could be shown by all applied statistical methods. The influence of posture on the prognostic value of the CL varied depending on the cut‐off value. Differences in CL or FW between 15–20 and 25–30 weeks predicted SPB better than did differences between shorter intervals.

Conclusions

Evaluation of the cervix with the woman in the upright position permits earlier detection of funneling. This may enable earlier and more appropriate intervention to avoid SPB. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
SINR estimation and orthogonality factor calculation of DS‐CDMA signals in MIMO channels employing linear transceiver filters
Authors: Logothetis Andrew , Osseiran Afif
Published: March 2006

A discrete‐time model of DS‐CDMA signaling using multiple transmit and receive antennas employing linear transceiver filters is derived. For each link, connecting a base‐station to a wireless mobile user, the downlink signal to interference plus noise ratio (SINR) after despreading is derived analytically, and as a by‐product an exact closed‐form solution of the orthogonality factor is obtained. The orthogonality factor is derived for any linear receiver structure that is implemented by a bank of correlators and for any linear combining techniques (such as MRC and MMSE), and for any number of transmit and/or receive antennas that utilize transmit (pre‐RAKE) and receive (post‐RAKE) filtering. The MIMO DS‐CDMA model is derived using a filter representation, and is extended to a vector/matrix formulation that permits a systematic and efficient way of computing the SINR in a radio network simulator. Copyright © 2006 John Wiley & Sons, Ltd.
Capacity of MIMO channels in the presence of co‐channel interference
Authors: Kang Ming , Yang Lin , Alouini Mohamed‐Slim
Published: March 2006

This paper presents analytical results on the capacity of multiple‐input‐multiple‐output (MIMO) fading channels in the presence of co‐channel interference (CCI). We consider the scenario in which the desired and CCI users are all subject to Rayleigh fading. We assume that channel realizations of both the desired and CCI users are known at the receiver. Moreover, we consider the case where the transmitter does not have any CSI and as such equal‐power allocation among transmit antennas is used. Given this setup, we derive the moment generating function (MGF) and the mean of the mutual information (MI). We then study the complementary cumulative distribution function of the MI using a Gaussian approximation. Finally, we present and discuss numerical examples to illustrate the mathematical formalism and to show the effect of various parameters on the capacity of MIMO channels in the presence of CCI. Copyright © 2006 John Wiley & Sons, Ltd.
Admission control for variable spreading gain CDMA cellular system with imperfect power control and shadowing
Authors: Siu Y. M. , Soo K. K. , Chan W. S. , Leung S. W.
Published: March 2006

Variable spreading gain (VSG) CDMA is the prime transmission scheme for supporting multiple services for the next generation cellular systems. As different services have different quality of service and data rate requirements, admission control is essential in safeguarding the performance of different services in VSG‐CDMA cellular systems in harsh wireless environment. In this paper, we propose an admission control scheme for multiple services VSG‐CDMA cellular system in a practical multi‐cell environment where there exist adverse effects due to imperfect power control and shadowing. Rather than with a fixed bound as in previous studies, the admission bound in our scheme is based on the probability distribution of total intra‐cell power (Pin) and other‐cell interference power (Iother). This is used to estimate the blocking probability by utilizing a simple and accurate approximation that incorporates the random nature of Pin and Iother. Evaluation of the impact of power control error to the mean and standard deviation of Pin and Iother, we performed and compared the blocking probability with fixed admission bound scheme in an integrated voice/data environment. Our work has enabled the calculation of the blocking probability and capacity of different mobility users having different power control errors under shadowing. Copyright © 2006 John Wiley & Sons, Ltd.
Local mean signal estimation over Nakagami‐m fading channels
Authors: Ko Young‐Chai , Alouini Mohamed‐Slim
Published: March 2006

Accurate and fast algorithms for the local mean signal level estimation are very important for the successful implementation of many wireless communication enabling techniques such as handoff, power control, and adaptive gain control schemes. In this paper, we present on‐line simple‐to‐implement (i) minimum variance unbiased and (ii) maximum likelihood estimators for the local mean signal power estimation in the decibel domain. We consider a generalized Nakagami‐m fading environment and show that these estimators are asymptotically efficient in the number of samples and in the fading parameter m. Numerical and simulation results confirm that these estimators outperform the sample mean estimator and quickly approach the Cramer–Rao lower bounds. Copyright © 2006 John Wiley & Sons, Ltd.
Hidden Markov modeling and macroscopic traffic filtering supporting location‐based services
Authors: Stamoulakatos Theodore S. , Sykas Efstathios D.
Published: March 2006

In this study, we present a technique that combines pattern recognition techniques with cellular signaling measurements and more precisely information extracted from Abis air interface in GSM network. The pattern recognition is applied to measurement reports that mobile terminal (MT) sends to its serving base station (BS). Modeling of these reports is performed by hidden Markov model (HMM) while employing clustering large applications (CLARA) as clustering method. The accurate results during MT velocity estimation located inside a probe vehicle show the potential of the method when applied to large scale of MTs in order to estimate basic parameters for road traffic. Copyright © 2006 John Wiley & Sons, Ltd.
Cross‐layer directional antenna MAC protocol for wirelessad hoc networks
Authors: Gossain Hrishikesh , Cordeiro Carlos , Joshi Tarun , Agrawal Dharma P.
Published: February 2006

In this paper, we propose a directional antenna medium access (DAMA) protocol and its enhanced version called enhanced DAMA (EDAMA), which takes advantage of the benefits offered by directional antennas. Both of these schemes have been inspired by the IEEE 802.11 MAC, with major enhancements including a new neighbor discovery scheme, an optimized circular directional transmission of RTS and CTS to prevent the hidden node problem, reduce collisions and decrease node deafness, and also a multi‐buffer management scheme. A pair of communicating nodes using these schemes simultaneously transmits the circular directional RTS and CTS only to those sectors with neighbors, hence reducing overall communication delay and enhancing throughput. The main difference between DAMA and EDAMA lies in the way buffering is provided in the MAC layer. Unlike DAMA, which uses a single MAC buffer for all antenna beams as in IEEE 802.11, EDAMA employs separate buffers for each of the antenna sectors and introduces an integrated network and MAC cross‐layer design. This helps in eliminating the ‘self‐induced blocking’ problem prominent in existing directional MAC protocols. We have compared DAMA, EDAMA, IEEE 802.11, and two recently proposed directional MAC protocols, and results show that DAMA and EDAMA perform better than existing MAC protocols in the majority of the scenarios investigated, while EDAMA is observed to perform best. We also point out that the performance usually depends on the network topology and traffic pattern. Copyright © 2006 John Wiley & Sons, Ltd.
Virtual backbone construction in multihop ad hoc wireless networks
Authors: Cheng Xiuzhen , Ding Min , Du David Hongwei , Jia Xiaohua
Published: February 2006

Recent research points out that the flooding mechanism for topology update or route request in existing ad hoc routing protocols greatly degrades the network capacity. If we restrict the broadcast of control packets within a small subset of hosts in the network, the protocol overhead can be substantially reduced. This motivates our research of constructing a virtual backbone by computing a connected dominating set (CDS) in unit‐disk graphs. In this paper, we propose two distributed algorithms to approximate a minimum CDS. These algorithms take linear time. Their performance is verified by a complete theoretical analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Approximation algorithms for conflict‐free channel assignment in wirelessad hocnetworks
Authors: Wan Peng‐Jun , Yi Chih‐Wei , Jia Xiaohua , Kim Dongsoo
Published: February 2006

Conflict‐free channel assignment is a classic and fundamental problem in wirelessad hocnetworks. It seeks an assignment of the fewest channels to a given set of radio nodes with specified transmission ranges without causing either primary collision or secondary collision. It is NP‐hard even when all nodes are located in a plane and have the same transmission radii. We observe that a prior analysis of the approximation ratio of a classic greedy heuristic, FIRST‐FIT in smallest‐last ordering, is erroneous. In this paper, we provide a rigorous and tighter analysis of this heuristic and other greedy FIRST‐FIT heuristics. We obtain an upper bound of 13 on the approximation ratios of both FIRST‐FIT in smallest‐last ordering and FIRST‐FIT in radius‐decreasing ordering. Such upper bound can be reduced to 12 if all nodes have quasi‐uniform transmission radii. When all nodes have equal transmission radii, we obtain an upper bound of 7 on the approximation ratios of FIRST‐FIT in smallest‐last ordering, FIRST‐FIT in distance‐increasing ordering, and FIRST‐FIT in lexicographic ordering. In addition, for nodes with equal transmission radii, we present a spatial divide‐and‐conquer heuristic with approximation ratios of 12. All these heuristics, except FIRST‐FIT in smallest‐last ordering, are modified to heuristics for maximum independent set with the same approximation ratios. Copyright © 2006 John Wiley & Sons, Ltd.
Channel‐relay price pair: towards arbitrating incentives in wireless ad hoc networks
Authors: Xue Yuan , Li Baochun , Nahrstedt Klara
Published: February 2006

Cooperation in wireless ad hoc networks has twofold implications. First, each wireless node does not excessively and greedily inject traffic to the shared wireless channel. Second, intermediate nodes voluntarily relay traffic for upstream nodes towards the destination at the cost of its own private resource. Such an assumption supports almost all existing research when it comes to protocol design in ad hoc networks. We believe that without appropriate incentive mechanisms, the nodes are inherently selfish (unwilling to contribute its private resource to relay traffic) and greedy (unfairly sharing the wireless channel). In this paper, we present a price pair mechanism to arbitrate resource allocation and to provide incentives simultaneously such that cooperation is promoted and the desired global optimal network operating point is reached by convergence with a fully decentralized self‐optimizing algorithm. Such desired network‐wide global optimum is characterized with the concept of Nash bargaining solution (NBS), which not only provides the Pareto optimal point for the network, but is also consistent with the fairness axioms of game theory. We simulate the price pair mechanism and report encouraging results to support and validate our theoretical claims. Copyright © 2006 John Wiley & Sons, Ltd.
Voronoi diagram and convex hull based geocasting and routing in wireless networks
Authors: Stojmenovic Ivan , Ruhil Anand Prakash , Lobiyal D. K.
Published: February 2006

In this paper, we propose a general algorithm (based on an unified framework for both routing and geocasting problems), in which message is forwarded to exactly those neighbors which may be best choices for a possible position of destination (using the appropriate criterion). We then propose and discuss new VD‐GREEDY and CH‐MFR methods and define R‐DIR, modified version of existing directional methods. In VD‐GREEDY method, these neighbors are determined by intersecting the Voronoi diagram of neighbors with the circle (or rectangle) of possible positions of destination, while the portion of the convex hull of neighboring nodes is analogously used in the CH‐MFR method. Routing and geocasting algorithms differ only inside the circle/rectangle. The proposed methods may be also used for the destination search phase allowing the application of different routing schemes after the exact position of destination is discovered. VD‐GREEDY and CH‐MFR algorithms are loop free, and have smaller flooding rate (with similar success rate) compared to directional method. We proposed to use dominating set concept to reduce flooding ratio significantly, with a marginal impact on success rate and hop count. Simulations, involving the proposed and some known algorithms, are performed for two basic scenarios, one for geocasting and reactive routing, and the other for proactive routing, and both showed that our methods have higher success rate and lower flooding rate compared to existing methods. Copyright © 2006 John Wiley & Sons, Ltd.
Precise 40Ar–39Ar ages from the metamorphic sole rocks of the Tauride Belt Ophiolites, southern Turkey: implications for the rapid cooling history
Authors: ÇELİK ÖMER FARUK , DELALOYE MICHEL , FERAUD GILBERT
Published: February 2006

The Tauride Belt Ophiolites in southern Turkey are located on both sides of the E–W-trending, Mesozoic Tauride carbonate platform. They comprise the Lycian, Antalya, Beyşehir, Mersin, Alihoca and Pozantı-Karsantı ophiolites from west to east. Each ophiolite has a metamorphic rock unit either at the base of the peridotites or in the mélange units. The metamorphic sole rocks generally consist of amphibolite at the top and near the contact with the overlying tectonized harzburgite of the ophiolites, and mica schists mostly at the base, near the tectonic contact with the underlying ophiolitic mélange. 40Ar–39Ar measurements from the metamorphic sole rocks of the Lycian, Antalya and Beyşehir ophiolites are the first precise ages dating intra-oceanic thrusting and the cooling age history during the closure of the Neotethyan Ocean. Amphiboles and white micas from the metamorphic sole rocks of the ophiolites yielded 40Ar–39Ar ages between 90.7 ± 0.5 Ma and 93.8 ± 1.7 Ma and between 91.2 ± 2.3 Ma and 93.6 ± 0.8 Ma, respectively. Hornblende plateau ages from the amphibolites of the Lycian ophiolites (near Köyceǧiz) agree with those of Antalya, indicating that they were metamorphosed simultaneously in the Neotethyan Ocean. The white micas display plateau ages concordant with the amphiboles from the same units in Köyceǧiz and Yeşilova (Lycian ophiolites) and from the Pozantı-Karsantı ophiolite, suggesting that the metamorphic sole rocks were rapidly cooled after their generation.
Rare cases of Ménière's disease in children
Authors: Choung Y H , Park K , Kim C H , Kim H J , Kim K
Published: March 2006

Classical Ménière's disease is rarely found in children and literature regarding it is scarce. In general, the frequency of Ménière's disease in children is only 0.4–7.0 per cent of that in adults. The progression pattern of Ménière's disease in children is not known well. Here, we report three cases of Ménière's disease in children less than 15 years old, treated over nine years. The three cases comprise 14- and 13-year-old boys and a nine-year-old girl. Two of the three patients initially complained only of recurrent bouts of vertigo, without any tinnitus, ear fullness or hearing impairment. In all three cases, the early pure tone audiograms showed only high tone frequency loss, regardless of subjective hearing loss, and the decrease in the hearing threshold was observed one to eight years after the dizziness attacks began. The hearing threshold was usually decreased to a level of mild or moderate hearing impairment. After diuretic treatment, vertigo was generally well controlled, and some cases showed improvement in hearing. Of the total number of patients with Ménière's disease who visited our department over nine years, 2.6 per cent (3/114) were children, and the overall incidence of Ménière's disease in children with vertigo was 2.0 per cent (3/147). In conclusion, Ménière's disease in children rarely develops and may have characteristics of high tone loss in initial audiograms.
Human-robot interaction detection: a wrist and base force/torque sensors approach
Authors: Lu Shujun , Chung Jae H. , Velinsky Stevens A.
Published: February 2006

In this paper, a collision detection and identification method of a manipulator, using wrist and base force/torque sensors, is presented. An impact model is used to simulate the interaction between the manipulator and the human or environment. A neural network approach and a model based method are developed to detect the collision forces and disturbance torques on the joints of the manipulator. The experimental results illustrate the validity of the developed collision detection and identification scheme.
A surface-shape recognition system mimicking human mechanism for tactile sensation
Authors: Ohka Masahiro , Takayanagi Jyunichi , Kawamura Takuya , Mitsuya Yasunaga
Published: February 2006

Tactile sensing is advantageous for the acquisition of local, proximal information such as the contact condition between a finger and an object. This type of sensing, however, is not suited for recognizing an entire object that is easily recognized by vision. The objective of this paper is to ease the limitations experienced in tactile sensing by using both a neural model based on the human tactile sensation and a tactile-oriented associative memory model to enable a robot to recognize object contours. In the model, first the direction vectors belonging to segments of the object contour are obtained from a filtered tactile pattern of the simulated neurons' excitation. Second, the vectors are quantized by the chain-symbolizing method and stored for use in a memory matrix that accumulates matrix-products between the vector and its transposition. In the recalling process, complete vectors are remembered even if some input vector elements are missing. In the experiments, a robotic manipulator equipped with a tactile sensor traces five types of contours, these being a circle, a square, a triangle, a star, and a hexagon. After the robot recalls the complete contours, it is able to recognize a complete contour by just touching even a part of a contour.
Determining the workspace boundary of 6-DOF parallel manipulators
Authors: Tsai K. Y. , Lee T. K. , Huang K. D.
Published: February 2006

The workspace boundary of 6-DOF parallel manipulators is a two-dimensional surface consisting of many patches that can be obtained by solving different sets of four constraint equations. This paper proposes algorithms for finding the equations to generate each patch of the boundary. Methods involving a searching technique are first developed to generate some small subsets of the boundary. The obtained data are then used to predict the equations for generating the rest of the boundary.
Biochemical fingerprinting of Vibrio parahaemolyticus by the PhenePlate system: comparison between pandemic and non-pandemic serotypes
Authors: RAHMAN MOKHLASUR , BHUIYAN N. A. , KUHN I. , RAMAMURTHY T. , RAHMAN M. , MOLLBY R. , NAIR G. BALAKRISH
Published: February 2006

During recent years a pandemic clone of Vibrio parahaemolyticus has emerged. Isolates of this clone are distributed among several serotypes, but are genotypically related. In the present study, a phenotyping method (biochemical fingerprinting) was used to characterize pandemic and non-pandemic isolates belonging to V. parahaemolyticus. It was found that the pandemic isolates showed a high level of phenotypic homogeneity and a majority of the pandemic isolates belonged to the same biochemical phenotype, whereas non-pandemic V. parahemolyticus isolates were more heterogeneous. In conclusion, biochemical fingerprinting of V. parahaemolyticus can be used as a first screening method to differentiate between pandemic and non-pandemic isolates of V. parahaemolyticus.
Prevalence and risk factors of Helicobacter pylori infection among healthy 3- to 5-year-old Israeli Arab children
Authors: MUHSEN KH. , ATHAMNA A. , ATHAMNA M. , SPUNGIN-BIALIK A. , COHEN D.
Published: March 2006

We determined the prevalence and risk factors of H. pylori infection among 197 healthy 3- to 5-year-old Israeli Arab children, in a population under socioeconomic and environmental transition. Data on the socioeconomic and environmental characteristics were obtained by personal interviews. The presence of H. pylori infection was identified using an ELISA kit for detection of H. pylori antigens in stool specimens. The prevalence rate of H. pylori infection was 49·7% (95% CI 42·8–56·67). It varied significantly among the different villages. In the univariate analysis stratified by village, the risk of infection increased according to household crowding, number of siblings younger than 5 years and siblings' H. pylori positivity. In the multivariate analysis the village of residence and siblings' H. pylori positivity were the only variables that remained strongly associated with H. pylori infection. In a population such as that described in this study the socioeconomic and living conditions are major risk factors of H. pylori infection and the intra-familial transmission of H. pylori in early childhood has an important role.
Evaluation of standardized scored inspections for Legionnaires' disease prevention, during the Athens 2004 Olympics
Authors: HADJICHRISTODOULOU Ch. , GOUTZIANA G. , MOUCHTOURI V. , KAPOULA Ch. , KONSTANTINIDIS A. , VELONAKIS E. , VATOPOULOS A. , KREMASTINOU J.
Published: February 2006

The study was designed to determine the contribution of standardized scored inspections implemented during the Athens 2004 Pre-Olympic and Olympic period, in assessing the presence of Legionella spp. in water sites. Inspection grading scores of 477 water supply systems, 127 cooling towers and 134 decorative fountains were associated with the corresponding microbiological test results of 2514 samples for Legionella spp. Nine violations of water supply systems and nine of cooling towers significantly associated with positive microbiological test results, and four violations of water supply systems and one of cooling towers were among those designated as ‘critical’ water safety hazards in the inspection reports. The study documents a strong correlation [water supply systems (RR 1·92), cooling towers (RR 1·94)] between unsatisfactory inspection scoring results and Legionella-positive microbiological test results (in excess of 10000 c.f.u./l) and suggests the utility of inspection scoring systems in predicting Legionella proliferation of water systems and in preventing Legionnaires' disease.
Type-safe run-time polytypic programming
Authors: WEIRICH STEPHANIE
Published: February 2006

Polytypic programming is a way of defining type-indexed operations, such as map, fold and zip, based on type information. Run-time polytypic programming allows that type information to be dynamically computed – this support is essential in modern programming languages that support separate compilation, first-class type abstraction, or polymorphic recursion. However, in previous work we defined run-time polytypic programming with a type-passing semantics. Although it is natural to define polytypic programs as operating over first-class types, such a semantics suffers from a number of drawbacks. This paper describes how to recast that work in a type-erasure semantics, where terms represent type information in a safe manner. The resulting language is simple and easy to implement – we present a prototype implementation of the necessary machinery as a small Haskell library.
Sex‐specific sibling interactions and offspring fitness in vertebrates: patterns and implications for maternal sex ratios
Authors: Uller Tobias
Published: February 2006

Vertebrate sex ratios are notorious for their lack of fit to theoretical models, both with respect to the direction and the magnitude of the sex ratio adjustment. The reasons for this are likely to be linked to simplifying assumptions regarding vertebrate life histories. More specifically, if the sex ratio adjustment itself influences offspring fitness, due to sex‐specific interactions among offspring, this could affect optimal sex ratios. A review of the literature suggests that sex‐specific sibling interactions in vertebrates result from three major causes: (i) sex asymmetries in competitive ability, for example due to sexual dimorphism, (ii) sex‐specific cooperation or helping, and (iii) sex asymmetries in non‐competitive interactions, for example steroid leakage between fetuses. Incorporating sex‐specific sibling interactions into a sex ratio model shows that they will affect maternal sex ratio strategies and, under some conditions, can repress other selection pressures for sex ratio adjustment. Furthermore, sex‐specific interactions could also explain patterns of within‐brood sex ratio (e.g. in relation to laying order). Failure to take sex‐specific sibling interactions into account could partly explain the lack of sex ratio adjustment in accordance with theoretical expectations in vertebrates, and differences among taxa in sex‐specific sibling interactions generate predictions for comparative and experimental studies.
Family Preservation Services on the Canary Islands
Authors: Rodrigo María José , Correa Ana Delia , Máiquez María Luisa , Martín Juan Carlos , Rodríguez Guacimara
Published: March 2006

This article describes the results of a parenting program “Apoyo Personal y Familiar,” (APF; Personal and Family Support program) targeted at parents of families at high psychosocial risk. APF aims at preventing unnecessary placement of children from vulnerable families into foster-care by increasing parental competence in order to improve their autonomous functioning. The program is implemented through group meetings in community centers. The method involves exposing the parents to parental views and practices in specific child-rearing episodes and encouraging them to reflect on their own views and the consequences on child development. In the Intervention group 144 mothers completed the pretest and posttest measures and 155 mothers were in a waiting-list comparison group. Self-report measures on parental implicit theories, child-rearing practices, and personal agency were used to perform the evaluation. Group discourse and the monitor's behavior observed during the sessions were used as predictors of the program's efficacy. Compared to control mothers, program mothers endorsed less simple views on child development, reported positive changes in their child-rearing practices, and had more confidence in their personal resources and a more accurate view of their parental role. Group effect sizes on the outcome measures were predicted by the type of group discourse and the type of group management observed during the sessions. The use of a perspectivist discourse was positive for promoting complex ideas and actions, whereas a self-centered discourse was positive for improving personal agency and for reporting less use of permissive practices. The role of the monitor was particularly relevant for reinforcing the mothers' sense of confidence in their own resources and for facilitating changes in child-rearing tactics.
Second‐mode internal tides in the East China Sea deduced from historical hydrocasts and a model
Authors: Park Jae‐Hun , Andres Magdalena , Martin Paul J. , Wimbush Mark , Watts D. Randolph
Published: February 2006

From historical hydrocasts in the Okinawa Trough region of the East China Sea (ECS), acoustic echo time from 700 dbar to the surface shows a tight relationship with temperature (T) except near the 100–200‐dbar layer. This is caused by 2nd‐ or higher‐mode baroclinic variations. Significant out‐of‐phase correlation between upper and lower layer T from the hydrocasts confirms that 2nd‐mode variations are strong. Furthermore, the 2nd‐mode variations are dominant during the ebb tide period, which suggests they are caused by 2nd‐mode internal tides (ITs) generated at the continental shelf break. For comparison, we investigate historical hydrocasts southeast of the Ryukyu Islands, where no significant 2nd‐mode variations are found. A model simulating the M2 IT agrees qualitatively with these observations: it predicts relatively strong 2nd‐mode IT energy in the ECS, but weak energy in the region southeast of the Ryukyu Islands.
Estimation of input energy in rocket‐triggered lightning
Authors: Jayakumar Vinod , Rakov Vladimir A. , Miki Megumu , Uman Martin A. , Schnetzer George H. , Rambo Keith J.
Published: February 2006

Electric fields in the immediate vicinity (within 0.1 to 1.6 m) of the triggered‐lightning channel were measured with Pockels sensors at the International Center for Lightning Research and Testing at Camp Blanding, Florida. These fields and the associated currents measured at the base of a 2‐m strike object were used to compute the input power and energy, each per unit channel length and as a function of time, associated with return strokes in rocket‐triggered lightning. In doing so, we assumed that the vertical component of the electric field at horizontal distances of 0.1 to 1.6 m from the lightning attachment point is not much different from the longitudinal electric field inside the channel (Borovsky, 1995). The estimated mean input energy over the first 50 μs or so is between 103 and 104 J/m, consistent with predictions of gas dynamic models, but one to two orders of magnitude smaller than Krider et al.'s (1968) estimate for a natural‐lightning first stroke, based on the conversion of measured optical energy to total energy using energy ratios observed in laboratory long‐spark experiments. The mean channel radius and resistance per unit channel length at the instance of peak power are estimated to be 0.32 cm and 7.5 Ω/m, respectively.
A network model of channel competition in fracture dissolution
Authors: Szymczak P. , Ladd A. J. C.
Published: February 2006

During dissolution in porous or fractured rock, a positive feedback between fluid transport and chemical reactions at the mineral surfaces may lead to the formation of pronounced, wormhole‐like channels. As the dissolution proceeds the channels interact, competing for the available flow, and eventually the growth of the shorter ones ceases. Thus the number of channels decreases with time while the characteristic distance between them increases, which leads to a scale‐invariant, power‐law distribution of channel lengths. A simple resistor network model of the evolution of dissolving channels is constructed and its properties studied. The results are compared with pore‐scale simulations of fracture dissolution using a microscopic, three‐dimensional numerical model. Despite its simplicity, the resistor model is found to retain the essential features of the nonlinear interaction between the channels.
Crustal versus asthenospheric origin of relief of the Atlas Mountains of Morocco
Authors: Missenard Yves , Zeyen Hermann , Frizon de Lamotte Dominique , Leturmy Pascale , Petit Carole , Sébrier Michel , Saddiqi Omar
Published: February 2006

We investigate the respective roles of crustal tectonic shortening and asthenospheric processes on the topography of the High Atlas and surrounding areas (Morocco). The lithospheric structure is modeled with a direct trial‐and‐error algorithm taking into account gravity (Bouguer and free air), geoid, heat flow, and topography. Three parallel cross sections, crossing the High Atlas and Anti‐Atlas ranges, show that the lithosphere is thinned to 60 km below these mountain ranges. An analysis of the effect of the lithospheric thinning allows us to conclude that the whole topography of the Anti‐Atlas, which belongs to the Sahara domain, is due to asthenospheric processes. In the High Atlas the lithospheric thinning explains a third of the relief of the western High Atlas, 500 m for a mean altitude of 1500 m, and half of the relief of the central High Atlas, 1000 m for a mean altitude of 2000 m. At the scale of Morocco the domain affected by lithospheric thinning forms an elongated NE‐SW strip crossing not only the main structural zones but also the Atlantic margin to the south and the Africa‐Eurasia plate boundary to the north. This major lithospheric thinning is associated with Miocene to recent alkaline volcanism and seismicity. We propose that this thermal anomaly is related to a shallow mantle plume, emplaced during middle to late Miocene time, during a period of relative tectonic quiescence.
How does climate change contribute to surface ozone change over the United States?
Authors: Murazaki K. , Hess P.
Published: February 2006

The impact of climate change on U.S. surface ozone levels is investigated. We simulated two 10 year periods using the global chemical transport model MOZART‐2 (Model of Ozone and Related chemical Tracers version 2): 1990–2000 and 2090–2100. In each case, MOZART‐2 is driven by meteorology from the National Center for Atmospheric Research (NCAR) coupled Climate Systems Model (CSM) 1.0 forced with the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1 scenario. During both periods the chemical emissions are fixed at 1990s levels, so that only changes in climate are allowed to impact ozone. The simulated surface ozone concentration during the 1990s is compared with observations from the Environmental Protection Agency's Aerometric Information Retrieval System (EPA AIRS) monitoring sites. Model‐measurement correlations are high, but MOZART‐2 overpredicts ozone especially over the eastern United States. The impact of climate change is calculated separately for background ozone and for the ozone generated through U.S. NOx emissions. Our results show that the response of ozone to climate change in polluted regions is not the same as in remote regions. MOZART‐2 predicts a 0–2 ppbv decrease in background ozone in the future simulation over the United States but an increase in ozone produced internally within the United States of up to 6 ppbv. The decrease in background ozone is attributed to a future decrease in the lifetime of ozone in regions of low NOx. Over the western United States the decrease in background ozone approximately cancels the increase in locally produced ozone. As a result, the main impact of future climate change on ozone is centered over the eastern United States, where future ozone increases up to 5 ppbv. We predict that in the future over the northeast United States, up to 12 additional days each year will exceed the maximum daily 8‐hour averaged ozone limit of 80 ppbv. Various climatic factors are identified which impact the net future increase in ozone over the United States including changes in temperature, water vapor, clouds, transport, and lightning NOx. Significant future changes are generally not found in planetary boundary layer height and precipitation.
Relationship between gross primary production and chlorophyll content in crops: Implications for the synoptic monitoring of vegetation productivity
Authors: Gitelson Anatoly A. , Viña Andrés , Verma Shashi B. , Rundquist Donald C. , Arkebauer Timothy J. , Keydan Galina , Leavitt Bryan , Ciganda Veronica , Burba George G. , Suyker Andrew E.
Published: February 2006

Accurate estimation of spatially distributed CO2 fluxes is of great importance for regional and global studies of carbon balance. We applied a recently developed technique for remote estimation of crop chlorophyll content to assess gross primary production (GPP). The technique is based on reflectance in two spectral channels: the near‐infrared and either the green or the red‐edge. We have found that in irrigated and rainfed crops (maize and soybean), midday GPP is closely related to total crop chlorophyll content. The technique provided accurate estimations of midday GPP in both crops under rainfed and irrigated conditions with root mean square error of GPP estimation of less than 0.3 mg CO2/m2s in maize (GPP ranged from 0 to 3.1 mg CO2/m2s) and less than 0.2 mg CO2/m2s in soybean (GPP ranged from 0 to 1.8 mg CO2/m2s). Validation using an independent data set for irrigated and rainfed maize showed robustness of the technique; RMSE of GPP prediction was less than 0.27 mg CO2/m2s.
Large‐scale changes in observed daily maximum and minimum temperatures: Creation and analysis of a new gridded data set
Authors: Caesar John , Alexander Lisa , Vose Russell
Published: February 2006

A gridded land‐only data set representing near‐surface observations of daily maximum and minimum temperatures (HadGHCND) has been created to allow analysis of recent changes in climate extremes and for the evaluation of climate model simulations. Using a global data set of quality‐controlled station observations compiled by the U.S. National Climatic Data Center (NCDC), daily anomalies were created relative to the 1961–1990 reference period for each contributing station. An angular distance weighting technique was used to interpolate these observed anomalies onto a 2.5° latitude by 3.75° longitude grid over the period from January 1946 to December 2000. We have used the data set to examine regional trends in time‐varying percentiles. Data over consecutive 5 year periods were used to calculate percentiles which allow us to see how the distributions of daily maximum and minimum temperature have changed over time. Changes during the winter and spring periods are larger than in the other seasons, particularly with respect to increasing temperatures at the lower end of the maximum and minimum temperature distributions. Regional differences suggest that it is not possible to infer distributional changes from changes in the mean alone.
Development and evaluation of a modified colorimetric solid‐phase microassay for measuring the activity of cellular and plasma (Factor XIII) transglutaminases
Authors: Thomas Vincent , El Alaoui Saïd , Massignon Denis , Clément Sophie , Simonet Frantz , Quash Gerard
Published: March 2006

Plasma TG (transglutaminase) [FXIII (Factor XIII)] stabilizes fibrin and plays an essential role in haemostasis. In the present paper, we report a simple colorimetric assay for measuring FXIII activity. The advantage of this approach, compared with all the other solid‐phase assays described so far for measuring TG activity, is that the first substrate, namely the synthetic dipeptide, N‐benzyloxycarbonyl‐l‐Gln‐l‐Gly, is coupled covalently by its C‐terminus with amine‐substituted polystyrene plates. Covalent coupling eliminates the problem of desorption of proteins such as casein and N,N′‐dimethylcasein (first substrates) when ‘blocking’ buffers containing proteins, e.g. BSA, are employed, or when samples of plasma or cell homogenates are used. The principle of the assay itself is based on the incorporation of the well‐known second substrate, 5‐(biotinamido)pentylamine, into the γ‐carboxamide of glutamine in the immobilized dipeptide. The amount of biotinylated amine bound to the plate, as measured by the phosphatase activity of Extravidin® phosphatase attached to the biotin moiety, is directly proportional to the TG activity. The method shows strong correlation (r=0.96) with the radiometric assay for FXIII activity. For plasma samples, a linear response was obtained in the range 0–1.33 i.u. (international unit)/ml, versus the Behring standard. In a preliminary clinical investigation, the method was applied to normal and pathological plasma samples from patients with liver failure and disseminated intravascular coagulation. In the isolation of TG from guinea‐pig liver, it was used to measure enzyme activity after each purification step. This method is rapid, sensitive and can easily be applied to routine clinical analyses and to specific research problems.
Toxoplasma gondiiacyl-lipid metabolism:de novosynthesis from apicoplast-generated fatty acids versus scavenging of host cell precursors
Authors: Bisanz Cordelia , Bastien Olivier , Grando Delphine , Jouhet Juliette , Maréchal Eric , Cesbron-Delauw Marie-France
Published: March 2006

Toxoplasma gondii is an obligate intracellular parasite that contains a relic plastid, called the apicoplast, deriving from a secondary endosymbiosis with an ancestral alga. Metabolic labelling experiments using [14C]acetate led to a substantial production of numerous glycero- and sphingo-lipid classes in extracellular tachyzoites. Syntheses of all these lipids were affected by the herbicide haloxyfop, demonstrating that their de novo syntheses necessarily required a functional apicoplast fatty acid synthase II. The complex metabolic profiles obtained and a census of glycerolipid metabolism gene candidates indicate that synthesis is probably scattered in the apicoplast membranes [possibly for PA (phosphatidic acid), DGDG (digalactosyldiacylglycerol) and PG (phosphatidylglycerol)], the endoplasmic reticulum (for major phospholipid classes and ceramides) and mitochondria (for PA, PG and cardiolipid). Based on a bioinformatic analysis, it is proposed that apicoplast produced acyl-ACP (where ACP is acyl-carrier protein) is transferred to glycerol-3-phosphate for apicoplast glycerolipid synthesis. Acyl-ACP is also probably transported outside the apicoplast stroma and irreversibly converted into acyl-CoA. In the endoplasmic reticulum, acyl-CoA may not be transferred to a three-carbon backbone by an enzyme similar to the cytosolic plant glycerol-3-phosphate acyltransferase, but rather by a dual glycerol-3-phosphate/dihydroxyacetone-3-phosphate acyltransferase like in animal and yeast cells. We further showed that intracellular parasites could also synthesize most of their lipids from scavenged host cell precursors. The observed appearance of glycerolipids specific to either the de novo pathway in extracellular parasites (unknown glycerolipid 1 and the plant like DGDG), or the intracellular stages (unknown glycerolipid 8), may explain the necessary coexistence of both de novo parasitic acyl-lipid synthesis and recycling of host cell compounds.