bluuebunny/crossref_metadata_2025 huggingface dataset:
Methodological quality of pharmacogenetic studies: Issues of concern
Authors: Jorgensen Andrea L. , Williamson Paula R.
Published: October 2008

Pharmacogenetic studies investigate association between genetic variants‡ and drug efficacy and toxicity. Regardless of the extent of current knowledge regarding the human genome‡ and relatively low genotyping costs, the value of pharmacogenetic studies in improving understanding of variable drug response remains contentious. Failure to replicate initial significant findings in subsequent studies is one reason for this and problems with methodological quality has been cited as contributing to this lack of replication. Here, concerns raised in the literature regarding the methodological quality of genetic association studies in general are discussed with particular consideration given to how applicable they are to the conduct and reporting of pharmacogenetic studies. Some of these issues such as sample size and quality of genotypes‡ have been given significant attention in the literature already whereas others, such as dealing with missing genotypes and assumptions regarding mode of inheritance, have been discussed very little. Issues of quality believed to be uniquely relevant to pharmacogenetic studies are also considered. These discussions close with an assessment of how well the issues are dealt with in pharmacogenetic studies published over recent years and, overall, methodological quality is found to be poor. A checklist is provided of issues to be addressed whenever a future pharmacogenetic study is embarked upon. Referring to this checklist will improve the chances of replication and instil confidence in the integrity of future pharmacogenetic studies. It will also serve as a tool in assessing methodological quality of studies included in a systematic review of pharmacogenetic studies. Copyright © 2008 John Wiley & Sons, Ltd.
Improving strategies for detecting genetic patterns of disease susceptibility in association studies
Authors: Calle M. L. , Urrea V. , Vellalta G. , Malats N. , Steen K. V.
Published: October 2008

The analysis of gene interactions and epistatic patterns of susceptibility is especially important for investigating complex diseases such as cancer characterized by the joint action of several genes. This work is motivated by a case‐control study of bladder cancer, aimed at evaluating the role of both genetic and environmental factors in bladder carcinogenesis. In particular, the analysis of the inflammation pathway is of interest, for which information on a total of 282 SNPs in 108 genes involved in the inflammatory response is available. Detecting and interpreting interactions with such a large number of polymorphisms is a great challenge from both the statistical and the computational perspectives. In this paper we propose a two‐stage strategy for identifying relevant interactions: (1) the use of a synergy measure among interacting genes and (2) the use of the model‐based multifactor dimensionality reduction method (MB‐MDR), a model‐based version of the MDR method, which allows adjustment for confounders. Copyright © 2008 John Wiley & Sons, Ltd.
The impact of time‐dependent bias in proportional hazards modelling
Authors: Beyersmann Jan , Wolkewitz Martin , Schumacher Martin
Published: October 2008

In the clinical literature, time‐dependent exposure status has regularly been analysed as if known at time origin. Although statisticians agree that such an analysis yields biased results when analysing the effect on the time until some endpoint of interest, this paper is the first to study in detail the bias arising in a proportional hazards analysis. We show that the biased hazard ratio estimate will always be less than the unbiased one; this leads to either an inflated or a damped effect of exposure, depending on the sign of the correct log hazard ratio estimate. We find an explicit formula of the asymptotic bias based on generalized rank estimators, and we investigate the role of censoring, which may prevent an individual from being considered as being baseline exposed in the biased analysis. We illustrate our results with data on hospital infection status and different censoring patterns. Copyright © 2008 John Wiley & Sons, Ltd.
Re‐estimating the sample size of an on‐going blinded trial based on the method of randomization block sums
Authors: Ganju Jitendra , Xing Biao
Published: October 2008

We extend a method we had previously described (Statist. Med.2005) to estimate the within‐group variance of a continuous endpoint without breaking the blind in a randomized clinical trial. Specifically, we: (a) explain how the method may be used for a wider set of designs than we had previously indicated; (b) obtain a within‐group, covariate‐adjusted, blinded variance estimator; (c) illustrate use of the method for sample size re‐estimation; and (d) describe a procedure to determine whether or not the blinded variance estimator works well not just on average but for the data set at hand. The proposed method is simple to use and makes no additional assumptions than is made for unblinded analysis. Simulations show that for realistic sample sizes there is virtually no inflation in the Type I error rate. When weighing the burden imposed by interim unblinded re‐estimation with the loss in precision with blinded re‐estimation, it may be advantageous for some trials to use the blinded method. Copyright © 2008 John Wiley & Sons, Ltd.
Empirical study of the dependence of the results of multivariable flexible survival analyses on model selection strategy
Authors: Binquet C. , Abrahamowicz M. , Mahboubi A. , Jooste V. , Faivre J. , Bonithon‐Kopp C. , Quantin C.
Published: October 2008

Flexible survival models, which avoid assumptions about hazards proportionality (PH) or linearity of continuous covariates effects, bring the issues of model selection to a new level of complexity. Each ‘candidate covariate’ requires inter‐dependent decisions regarding (i) its inclusion in the model, and representation of its effects on the log hazard as (ii) either constant over time or time‐dependent (TD) and, for continuous covariates, (iii) either loglinear or non‐loglinear (NL). Moreover, ‘optimal’ decisions for one covariate depend on the decisions regarding others. Thus, some efficient model‐building strategy is necessary.

We carried out an empirical study of the impact of the model selection strategy on the estimates obtained in flexible multivariable survival analyses of prognostic factors for mortality in 273 gastric cancer patients. We used 10 different strategies to select alternative multivariable parametric as well as spline‐based models, allowing flexible modeling of non‐parametric (TD and/or NL) effects. We employed 5‐fold cross‐validation to compare the predictive ability of alternative models.

All flexible models indicated significant non‐linearity and changes over time in the effect of age at diagnosis. Conventional ‘parametric’ models suggested the lack of period effect, whereas more flexible strategies indicated a significant NL effect. Cross‐validation confirmed that flexible models predicted better mortality. The resulting differences in the ‘final model’ selected by various strategies had also impact on the risk prediction for individual subjects.

Overall, our analyses underline (a) the importance of accounting for significant non‐parametric effects of covariates and (b) the need for developing accurate model selection strategies for flexible survival analyses. Copyright © 2008 John Wiley & Sons, Ltd.
Statistical issues in the design and analysis of expertise‐based randomized clinical trials
Authors: Walter S. D. , Ismaila A. S. , Devereaux P. J.
Published: October 2008

In order to avoid certain difficulties with the conventional randomized clinical trial design, the expertise‐based design has been proposed as an alternative. In the expertise‐based design, patients are randomized to clinicians (e.g. surgeons), who then treat all their patients with their preferred intervention. This design recognizes individual clinical preferences and so may reduce the rates of procedural crossovers compared with the conventional design. It may also facilitate recruitment of clinicians, because they are always allowed to deliver their therapy of choice, a feature that may also be attractive to patients.

The expertise‐based design avoids the possibility of so‐called differential expertise bias. If a standard treatment is generally more familiar to clinicians than a new experimental treatment, then in the conventional design, more patients randomized to the standard treatment will have an expert clinician, compared with patients randomized to the experimental treatment. If expertise affects the study outcome, then a biased comparison of the treatment groups will occur.

We examined the relative efficiency of estimating the treatment effect in the expertise‐based and conventional designs. We recognize that expected patient outcomes may be better in the expertise‐based design, which in turn may modify the estimated treatment effect. In particular, a larger treatment effect in the expertise‐based design can sometimes offset a higher standard error arising from the confounding of clinician effects with treatments.

These concepts are illustrated with data taken from a randomized trial of two alternative surgical techniques for tibial fractures. Copyright © 2008 John Wiley & Sons, Ltd.
PalaisQuartier Frankfurt: Zeilforum – Planung und Ausführung der architektonischen Gebäudehülle
Authors: Stroetmann Richard , Istel Roger , Hanek Dieter
Published: October 2008

In Frankfurt wird zur Zeit in zentraler Innenstadtlage das PalaisQuartier errichtet, ein Gebäudekomplex mit vielfältiger Nutzung. Wesentlicher Bestandteil ist das Zeilforum mit rund 78000 m2 BGF, das durch seine avantgardistische Architektur Akzente setzt. Im Kontext des städtebaulichen Wettbewerbs und der Einbindung in das Gesamtprojekt wird im folgenden Beitrag die Planung und Ausführung des rund 13500 m2 großen Freiformdachs und der Sonderfassaden beschrieben. Dabei wird auf Besonderheiten des Tragwerksentwurfs und der statischen Berechnung, die bauliche Umsetzung und Qualitätssicherung eingegangen.
Partnering – ein Weg zur effizienten Projektabwicklung komplexer Bauten – BMW‐Welt München als Modell für eine neue Partnerschaft am Bau
Authors: Franke Armin , Grebenc Herbert
Published: October 2008

Die BMW‐Welt ist sicher ein einzigartiges Bauwerk aus Stahl und Glas. Seine Konstruktion erforderte extrem komplizierte statische Berechnungen sowie eine 3D‐basierte Planung und Design. Architekt Wolf D. Prix von Coop Himmelb(l)au zählt den Bau zu den “ersten Werken einer neuen Generation von Kommunikationsbauten für das 21.Jahrhundert”. Ihre transparente und komplexe Glasfassade wird selbst zum Kunstwerk, gibt dem Gebäude ein unverwechselbares Gesicht und wird wesentlicher Teil des Brandings. Von Fassaden‐ und Metallbauern erfordern solche außergewöhnlichen Gebäudeformen ein Höchstmaß an Präzision und Qualität, aber auch die frühzeitige Einbindung in die Planung und Entwicklung. Deshalb eignet sich das Partnerschaftsmodell für alle anspruchsvollen Bauten mit einem hohen Komplexitäts‐ und Innovationsgrad. Um neue gestalterische Möglichkeiten im architektonischen Stahlbau termin‐, kosten‐ und qualitätsgerecht zu realisieren, ist die partnerschaftliche Zusammenarbeit im Baumanagement effizienter als die in Deutschland übliche klassische Projektabwicklung.
Zum Thema “Nachhaltigkeit” in der Stahlbauindustrie
Authors: Feldmann Markus , Döring Bernd , Kuhnhenne Markus , Sedlacek Gerhard
Published: October 2008

Die Forderung nach nachhaltigem Bauen ist die Folge von Defiziten, die bei Gebäuden in Hinblick auf Klimaschutz und Energieeffizienz bestehen. Bewertungssysteme für die Nachhaltigkeit werden in Zukunft für den Wettbewerb im Markt von Ingenieur‐ und Bauleistungen und im Immobilienmarkt eine große Rolle spielen. Das deutsche Bewertungssystem des “Runden Tisches” und der Deutschen Gesellschaft für nachhaltiges Bauen (DGNB) liefert nachvollziehbare quantitative Nachhaltigkeitsmerkmale und hat damit als Kommunikationsplattform große Vorteile gegenüber bestehenden Systemen.

Da die Energieeffizienz für die Nachhaltigkeitsbewertung von Gebäuden dominant ist, wird anhand von Beispielen aus dem Stahlbau gezeigt, wie durch Zusammenführen verschiedener Aspekte wie Tragfähigkeit, Gebrauchstauglichkeit und Energieeffizienz neue innovative Lösungen für Bauprodukte und vorgefertigte Bauteile entstehen. Das führt zum “integrierten Entwurf”. Nachhaltiges Bauen eröffnet auch für den Stahlbau neue Felder für Technik, Markt, Forschung und Entwicklung.
Schweißen unter dynamischer Einwirkung
Authors: Peil Udo , Hoeft Tina , Reininghaus Matthias , Wichers Michael
Published: October 2008

Im Verlauf von Instandhaltungs‐ und Sanierungsmaßnahmen kann es erforderlich werden, Reparaturschweißungen an Bauwerken unter dynamischer Beanspruchung, d. h. bei gleichzeitiger Bewegung der Schweißnahtflanken durchzuführen. Aufgrund des Fehlens von technischen oder normativen Regelungen ist eine derartige Vorgehensweise im bauaufsichtlichen Bereich nicht zulässig, so dass häufig aufwendige Entlastungskonstruktionen zur Fixierung der Nahtflanken notwendig werden. In einigen Fällen lässt sich die dynamische Beanspruchung auch nicht beseitigen und damit eine Nahtflankenbewegung nicht verhindern. Mit Hilfe schweißtechnischer Simulationen in einer zweiachsigen, vollautomatischen Prüfmaschine wird daher untersucht, inwieweit Schweißungen unter Bewegung sinnvoll herzustellen sind. In der nachstehenden Ausführung werden Ergeb‐nisse zum statischen und dynamischen Tragverhalten unter Bewegung geschweißter Nähte gezeigt.
Schweißnahtnachbehandlung in der Praxis
Authors: Weich Imke , Ummenhofer Thomas
Published: October 2008

Durch die Nachbehandlung von Schweißnähten kann die Ermüdungsfestigkeit neuer sowie bestehender Stahlbauteile erheblich gesteigert werden. Im Rahmen des großen Forschungsvorhabens REFRESH werden derzeit mit Industriepartnern mehrerer Branchen die Vorteile und die Anwendung höherfrequenter Hämmerverfahren untersucht. Neben klassischen Wöhlerversuchen stehen Untersuchungen zur Qualitätssicherung und die Ermüdungsbemessung unter Berücksichtigung der die Lebensdauer massiv erhöhenden Nachbehandlungsverfahren im Fokus. Die bisherigen Ergebnisse des Forschungsprojekts sind so positiv, dass sämtliche beteiligten Industriepartner bereits im Rahmen von Pilotprojekten die Verfahren HiFIT bzw. UIT bei der Herstellung und in situ anwenden.
Die neue DASt‐Richtlinie zur Vermeidung von Rissbildung beim Feuerverzinken
Authors: Feldmann Markus , Pinger Thomas , Sedlacek Gerhard , Tschickardt Dirk
Published: October 2008

Über gehäufte Risserscheinungen an feuerverzinkten Stahlkonstruktionen einhergehend mit Standsicherheitsproblemen ist in letzter Zeit mehrfach berichtet worden [1] bis [6]. Ein mit zahlreichen Vertretern der betroffenen Industriekreise, der Behörden und der Universitäten sowie Beobachtern aus England und Italien und einem Berater aus Österreich besetzter Unterausschuss “DASt‐Richtlinie Rissfreies Verzinken” wurde deswegen gegründet, in dem eine Technische Regel erarbeitet wird, die die Vermeidung von Rissbildung beim Feuerverzinken von den vielfältigen Ursachen her angeht und die Einzelbeiträge quantitativ in den Zusammenhang eines Grenzzustands der Rissbildung bringt. So werden Zulässigkeitsgrenzen für Stahlbau und Verzinkung angeboten mit der gleichzeitigen Möglichkeit, auch zukünftige Neuentwicklungen zu berücksichtigen. Zusammen mit wesentlichen Ergänzungen zur Überwachung und zu vorhandenen allgemeinen Normen werden Voraussetzungen für das problemlose und weiterhin einfache Feuerverzinken im bauaufsichtlichen Bereich geschaffen. Grundlagen, Ziel und Konzept der neuen DASt‐Richtlinie werden im Folgenden vorgestellt.
Brückenbauwerke mit Stahlhohlprofilen – Konstruktive Ausführung
Authors: Friedrich Heinz , Quaas Bert
Published: October 2008

In den letzten Jahren wurde der moderne Brückenbau durch elegante Fachwerkkonstruktionen aus Stahlhohlprofilen bereichert. Die Realisierung solcher Bauwerke ist jedoch mit einem hohen Aufwand verbunden, da die aktuellen Normen und Richtlinien keine optimale Bemessung erlauben. Aus diesem Grunde wurden zwei Forschungsprojekte initiiert, um brückenbaurelevante Konstruktionsdetails zu untersuchen. Im Beitrag werden die Ergebnisse der Arbeiten vorgestellt.
Die neuen Stabilitätsnachweise im Stahlbau nach Eurocode 3
Authors: Naumes Johannes , Strohmann Isabel , Ungermann Dieter , Sedlacek Gerhard
Published: October 2008

Stahlbauten sind Leichtbauten mit großen Vorteilen für die sthetik und die Nachhaltigkeit. Dieser Vorteil wird mit größerem Aufwand bei den Stabilitätsnachweisen erkauft. Im Eurocode 3 – Teil 1 “Entwurf und Berechnung von Stahlbauten – Grundregeln und Regeln für den Hochbau” sind die Stabilitätsregeln für Stabwerke, Plattenbeulen und Schalentragwerke zusammengestellt. Sie enthalten geometrische Ersatzimperfektionen für Nachweise nach Theorie 2. Ordnung oder Bemessungsformeln für Bauteilnachweise, die bereits Imperfektionen enthalten. Dieser Beitrag behandelt insbesondere die Konsistenz von Imperfektionsangaben und den Nachweisformeln für Bauteile. Eine solche Konsistenz besteht beim Knickstabnachweis, da die Knickformel mit einem Imperfektionsmodell abgeleitet wurde. Beim Biegedrillknicken, und Biegedrillknicken mit oder ohne Druckkraft und mit oder ohne zweiachsige Biegung ist aber die Konsistenz nicht ohne weiteres offensichtlich. Um die Situation zu klären, liefert der Beitrag einen Leitfaden für die Anwendung der sogenannten “Allgemeinen Methode” im Eurocode 3 – Teil 1‐1, der es ermöglicht, die Biege‐ und Biegedrillknickfälle mit Druckkraft, einachsiger und zweiachsiger Biegung für beliebige Randbedingungen einfach nachzuweisen. Diese allgemeine Methode ist zuverlässigkeitsmäßig nach EN 1990 – Anhang D überprüft, und es werden Vergleiche mit Resultaten von Alternativmethoden im Eurococde 3 – Teil 1‐1 angegeben.
Following the money: The globalization of capital flows and private equity
Authors: Quinlan Joseph
Published: October 2008

Global capital flows have long been the domain of the developed nations. The emerging markets, at best, have been nominal players. Today, the tables have begun to turn. The developing nations have become bigger players as global growth increasingly shifts toward the Middle East, Asia, Central Europe, and Latin America. Accordingly, global capital flows are slowly being reconfigured; in the future, flows will increasingly take the form of north‐south movements, or flows between the developed and developing nations. They will also become south‐south in nature, as well as south‐north. Private equity, long driven by U.S. players, will become less U.S.‐centric in the future. © 2008 Wiley Periodicals, Inc.
Indian economy and Indian private equity
Authors: Ratanpal Amit
Published: October 2008

India's gross domestic product has been growing at more than 8% in the past few years, making it the fourth‐largest economy in terms of purchasing power parity. According to a Goldman Sachs report, India could become the second‐largest economy in the world by 2050. The key growth drivers are investments in infrastructure, domestic consumption, and a hub for global outsourcing. This is further supported by growth‐oriented policies by the government. The favorable environment has led to the growth of the private equity market. India received approximately U.S. $17.5 billion of investments in private equity in 2007, making it the number‐one destination in Asia. Indian private equity has been mainly focused on providing growth/expansion capital to the company as compared to buyouts in the developed markets. © 2008 ICICI Bank Limited. Printed with permission.
Private equity, Islamic finance, and sovereign wealth funds in the MENA region
Authors: Karake‐Shalhoub Zeinab
Published: October 2008

The Middle East and North Africa region has experienced a significant amount of activity in the past few years, despite the worldwide economic problems caused by the subprime crisis. A strong influx of petrodollar reserves, sustainable economic growth, limited reliance on leverage, and limited exposure to the global credit markets have kept the region relatively outside the economic mishaps overwhelming a number of economies, especially in the West. Shariah‐compliant, Islamic private equity funds and the use of sovereign wealth funds as sources of private equity in the region are two important evolutionary developments to watch in the next few years. © 2008 Wiley Periodicals, Inc.
Public market finance for growth‐stage companies in emerging markets: The U.S. alternative IPO moves to fill the gap
Authors: Efird Christopher
Published: October 2008

Lacking from the options currently available to most growth‐stage companies located in the emerging markets of the world is effective access to public finance. Unlike the United States, these companies are shut off from access to their local public markets. Fortunately a solution exists in the form of an alternative initial public offering (AIPO) onto the over‐the‐counter bulletin board market of the United States (OTC BB). As the name implies, an AIPO is an alternative form of listing that allows companies in emerging markets to gain access to the deepest and most liquid capital market in the world. © 2008 Wiley Periodicals, Inc.
Percutaneous ultrasound‐guided stenting of the atrial septum in fetal sheep
Authors: Schmidt M. , Jaeggi E. , Ryan G. , Hyldebrandt J. , Lilly J. , Peirone A. , Benson L. , Chaturvedi R. R.
Published: October 2008

Objectives

Hypoplastic left heart syndrome (HLHS) with a restricitive foramen ovale is associated with high mortality related to fetal left atrial hypertension. Fetal atrial balloon septoplasty has largely failed to achieve adequate decompression due to the small size of the holes produced. We attempted to produce larger atrial communications by stenting the atrial septum in fetal sheep using a minimally invasive technique.

Methods

We used a percutaneous, ultrasound‐guided transpulmonary or transhepatic approach to attempt deployment of coronary stents (2–5 mm in diameter and 13–23 mm in length) in the atrial septum primum of 10 normal fetal sheep.

Results

Coronary stents were deployed in eight of the 10 fetal sheep (119–139 days' gestation). The transhepatic route was unsuccessful (n = 2). Transpulmonary implantation was only possible in prone fetuses, so three initially supine fetuses underwent external version. Small coronary stents (2.0–2.5 mm in diameter) were deployed rapidly without complication via an 18G needle (n = 4). Larger coronary stents (5 mm in diameter) were delivered through a 4F sheath, but a right pleural effusion occurred in three of the four cases, related to inferior vena cava injury by the balloon. One stent dislodged from a floppy septum. Another was partially occluded within a week by endocardial cells.

Conclusions

Percutaneous ultrasound‐guided deployment of coronary stents into the septum primum is feasible without laparotomy or uterine exteriorization in fetal sheep. Partial luminal occlusion by rapid proliferation of endocardial cells is a concern. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Prediction of acidemia at birth by Doppler assessment of fetal cerebral transverse sinus in pregnancies with placental insufficiency
Authors: Barbosa M. M. , Carvalho F. H. C. , Araujo Júnior E. , Nardozza L. M. M. , Santana R. M. , Torloni M. R. , Moron A. F.
Published: October 2008

Objectives

To evaluate the prediction of acidemia at birth using cerebral transverse sinus (CTS) Doppler velocimetry and to determine the best parameter and cut‐off values for its prediction in pregnancies complicated with placental insufficiency.

Methods

This was a prospective cross‐sectional study involving 69 pregnant women (26–40 weeks' gestation) with placental insufficiency managed in two Brazilian hospitals. Doppler assessment of the CTS was carried out in the last 24 h before delivery, and the peak ventricular systolic (S‐wave) and diastolic (D‐wave) velocities as well as the atrial systolic velocity (A‐wave) were recorded and the pulsatility index for veins (PIV) was calculated. At birth, arterial and venous umbilical cord blood samples were collected to determine acid–base and pH status. A receiver–operating characteristics (ROC) curve was constructed for each Doppler parameter with birth acidemia as the dependent variable. Sensitivity, specificity, positive and negative predictive values, accuracy and false‐positive and false‐negative rates were calculated for the parameters considered to be good predictors of acidemia.

Results

The S, D and A peak velocities and the S/A ratio were not good predictors of acidemia at birth. The PIV and the (S − A)/S ratio were good predictors of acidemia (area under the ROC curve = 0.698 (P = 0.009) and 0.654 (P = 0.009), respectively). The cut‐off values were PIV = 0.855 and (S − A)/S = 0.703).

Conclusions

The PIV and the (S − A)/S ratio of the CTS were good predictors of acidemia at birth in this high‐risk population with placental insufficiency. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Isolated or non‐isolated duodenal obstruction: perinatal outcome following prenatal or postnatal diagnosis
Authors: Cohen‐Overbeek T. E. , Grijseels E. W. M. , Niemeijer N. D. , Hop W. C. J. , Wladimiroff J. W. , Tibboel D.
Published: October 2008

Objectives

To determine whether the pre‐ or postnatal diagnosis of either isolated or non‐isolated duodenal obstruction (DO) is associated with different outcomes.

Methods

A single‐center retrospective analysis was carried out of 91 cases diagnosed with a DO between January 1991 and June 2003. Data on the diagnosis, treatment and outcomes of the cases were gathered, and differences between the groups were analyzed.

Results

Twenty‐eight cases of DO were diagnosed before and 63 after birth. Of 15 presumed isolated cases in the prenatally diagnosed group, four revealed associated or chromosomal anomalies after birth. The types of obstruction present were significantly different between the prenatally (n = 11) and postnatally (n = 27) detected subsets of isolated DO. The prenatally detected subset displayed a lower median gestational age at delivery, lower median birth weight and a higher prematurity rate (8/11 vs. 8/27). The diagnosis of DO occurred significantly later in the postnatally detected subset than the postnatal confirmation of the diagnosis in the prenatally detected cases. In the non‐isolated cases of DO, no difference was found in the type of chromosomal or associated anomaly or the type of obstruction between the prenatally detected (n = 17) and postnatally detected subsets (n = 36). Trisomy 21 was present in 7/17 (41%) vs. 22/36 (61%) cases, respectively. Two terminations and three intrauterine deaths occurred in the prenatal non‐isolated subset. The liveborn infants from the prenatally detected non‐isolated subset (n = 12) showed a significantly higher prematurity rate (9/12 vs.14/36), lower median birth weight and earlier confirmation of diagnosis after delivery. After surgery, outcome was similar between both subsets of isolated and non‐isolated DO. All the infants with an isolated DO survived. Neonatal death occurred in three prenatally and five postnatally diagnosed cases with non‐isolated DO.

Conclusions

The outcome of prenatally and postnatally diagnosed DO is not essentially different despite more prematurity and a lower birth weight in the former. Of the prenatally detected cases of DO assumed to be isolated, 25% revealed additional chromosomal or associated anomalies after delivery, which influenced outcome. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
GE‐MXRF analysis of multilayer films
Authors: Yang Jun , Tsuji Kouichi , Han Dongyan , Ding Xunliang
Published: October 2008

Polycapillary x‐ray optics (capillary x‐ray lens) is now popular in x‐ray fluorescence (XRF) analysis. Such an x‐ray lens can collect x‐rays emitted from an x‐ray source in a large solid angle and form a very intense x‐ray microbeam which is very convenient for micro x‐ray fluorescence (MXRF) analysis. In this paper, a new method called grazing exit micro x‐ray fluorescence analysis (GE‐MXRF), which combines an x‐ray lens used to form an intense XRF source was developed and applied in multilayer film analysis. Such a method can give the information of film composition, density, and thickness. Through two‐dimensional scan of the film sample, the information of film uniformity can be acquired; meanwhile, this method is also useful in adjusting experiment condition during the film preparation with metal vapor vacuum arc (MEVVA) source ion implantation. Copyright © 2008 John Wiley & Sons, Ltd.
Experimental evaluation of X‐ray optics applied for microanalysis
Authors: Wegrzynek D. , Mroczka R. , Markowicz A. , Chinea‐Cano E. , Bamford S.
Published: October 2008

The performance of x‐ray capillary lenses has been evaluated. The tests were carried out using an x‐ray tube set‐up. A single glass capillary with tapered inner channel, a monolithic glass polycapillary, and an in‐house manufactured single metallic capillary with parabolic inner channel were characterized in terms of gain, spatial resolution, and element detection limits. The spatial resolution of a confocal set‐up utilizing a monolithic glass polycapillary and a polycapillary conical collimator has also been measured. The highest gain of about 2500 was observed for the glass polycapillary. The maximum gain achieved with the single glass capillary was equal to about 25, and the gain of the metallic capillary was only slightly greater than 1. For the glass capillary and polycapillary lenses, significant filtering of the higher‐energy photons (energy > 8 keV) was observed. The lowest relative detection limits were obtained with an ordinary cylindrical collimator and the polycapillary lens. Similar absolute detection limits were achieved with the use of the polycapillary and single capillary lenses. A relation between the ratios of the detection limits of elements achieved with different x‐ray lenses and the lens parameters (spatial resolution and gain) has been proposed and was verified experimentally. The monolithic polycapillary lens was found to be an optimum focusing device for an x‐ray tube‐based scanning spectrometer. This type of x‐ray lens can be coupled with a polycapillary conical collimator or a polycapillary half‐lens to make a confocal x‐ray microscope capable of depth profiling with a spatial resolution equal to about 30 micrometers. Copyright © 2008 John Wiley & Sons, Ltd.
An intercontinental comparison of the dynamic behavior of mast seeding communities
Authors: Kelly Dave , Koenig Walter D. , Liebhold Andrew M.
Published: October 2008

Cases of mast seeding, involving highly variable seed production synchronized over large geographic areas, provide dramatic examples of resource pulses that have been documented for most major world land masses. Here, we compare the dynamic behavior of two of these systems, with the goal of understanding differences in the long‐term consequences of masting events to their respective communities. Responses to mast events in deciduous oak forests in eastern North America are characteristically complex and of low resilience. That is, each event produces long‐lasting cascading effects in the community, ultimately influencing not only seed consumers such as rodents and deer, but also the parasites and prey of those consumers, diseases transmitted by those parasites, and outbreaks of insect herbivores. In contrast, despite more extreme resource pulsing in New Zealand Nothofagus forests, responses to mast events there are less complex and more resilient, i.e., producing only short‐term (<2 years), smoothly damped, numerical responses by a few species, except after (rare) ‘double‐mast’ events in consecutive years. A detailed examination of the two systems suggests some tentative explanations for the strongly contrasting dynamics of these systems. Firstly, the higher number of species involved in North America seems to reduce resilience by increasing food chain length, lags, and alternative prey, all of which increase the dynamic complexity compared with that in New Zealand. Secondly, lack of a shared evolutionary history among species did not necessarily reduce resilience. Some exotic species showed well‐damped fluctuations (e.g., stoats (Mustela erminea L.) in New Zealand), while other exotics showed complex dynamics (e.g., gypsy moths (Lymantria dispar L.) in North America). Thirdly, recent extinctions of species such as the passenger pigeon (Ectopistes migratorius L.), once the dominant acorn predator in eastern North American forests, have likely produced qualitative changes in system dynamics in both communities. Fourthly, the North American community has more lags and hysteresis, which probably contribute to the greater dynamic complexity in eastern North America than in New Zealand Nothofagus forests. However, positive feedback loops present in North America seem to have little influence on system dynamics. Because the massive perturbations induced by masting events are major recurring challenges to an ecosystem, disentangling the causes of different system responses is likely to lead us to a better understanding of ecosystem function, resilience and stability.
Virtual MR arthroscopy of the shoulder: image gallery with arthroscopic correlation of major pathologies in shoulder instability
Authors: Stecco A. , Volpe D. , Volpe N. , Fornara P. , Castagna A. , Carriero A.
Published: October 2008

Background

The purpose of this study was to compare virtual MR arthroscopic reconstructions with arthroscopic images in patients affected by shoulder joint instability. MR arthrography (MR-AR) of the shoulder is now a well-assessed technique, based on the injection of a contrast medium solution, which fills the articular space and finds its way between the rotator cuff (RC) and the glenohumeral ligaments. In patients with glenolabral pathology, we used an additional sequence that provided virtual arthroscopy (VA) post-processed views, which completed the MR evaluation of shoulder pathology.

Materials and methods

We enrolled 36 patients, from whom MR arthrographic sequence data (SE T1w and GRE T1 FAT SAT) were obtained using a GE 0.5 T Signa—before any surgical or arthroscopic planned treatment; the protocol included a supplemental 3D, spoiled GE T1w positioned in the coronal plane. Dedicated software loaded on a work-station was used to elaborate VAs. Two radiologists evaluated, on a semiquantitative scale, the visibility of the principal anatomic structures, and then, in consensus, the pathology emerging from the VA images.

Results

These images were reconstructed in all patients, except one. The visualization of all anatomical structures was acceptable. VA and MR arthrographic images were fairly concordant with intraoperative findings.

Conclusions

Although in our pilot study the VA findings did not change the surgical planning, the results showed concordance with the surgical or arthroscopic images.
Recognition of scent marks in solitary bees to avoid previously visited flowers
Authors: Yokoi Tomoyuki , Fujisaki Kenji
Published: October 2008

Knowing how floral visitors forage efficiently among flowers is important to understanding plant‐pollinator interactions. When bees search for rewarding flowers, they use several visual cues to detect the available floral resources. In addition to these cues, bees can recognize scent marks, which are olfactory cues left on flowers foraged by previous visitors. This behavior is well known in social bees, such as honeybees and bumblebees. Although solitary bees do not need to give information about which flowers were foraged to conspecifics, several pieces of evidence have indicated the use of scent marks. However, it is unknown whether the behavior is widely used in many different bee species. We investigated whether four different solitary bees, Colletes patellatus (Colletidae), Andrena prostomias (Andrenidae), Osmia orientalis (Megachilidae), and Tetralonia mitsukurii (Apidae), can recognize flowers that have been foraged previously by visitors within 3 min. All four bees showed rejection responses to flowers foraged by conspecifics. However, our results showed that responses to foraged flowers varied among bee species. The tendency of A. prostomias and T. mitsukurii to reject the foraged flowers was pronounced, while in C. patellatus and O. orientalis it was weak. In both A. prostomias and T. mitsukurii, the rejection rate of flowers foraged by conspecifics decreased as the time lag after the last visit increased. Both bees visited the flowers from which pollen or nectar had been artificially removed. We suggest that A. prostomias and T. mitsukurii would recognize scent marks left by previous visitors, while the other two bees would not recognize them so strongly. It is likely that the decision to use scent marks is dependent either on the richness of resources or on the complexity of floral structure.
Mode of death in patients with newly diagnosed heart failure in the general population
Authors: Mehta Paresh A. , Dubrey Simon W. , McIntyre Hugh F. , Walker David M. , Hardman Suzanna M.C. , Sutton George C. , McDonagh Theresa A. , Cowie Martin R.
Published: October 2008

Background:

Early prognosis for incident (new) heart failure (HF) patients in the general population is poor. Clinical trials suggest approximately half of chronic HF patients die suddenly but mode of death for incident HF cases in the general population has not been evaluated.

Aims:

To describe mode of death in the first six months after a new diagnosis in the general population.

Methods:

Two‐centre UK population‐based study.

Results:

396 incident HF patients were prospectively identified. Overall mortality rates were 6% [3–8%], 11% [8–14%] and 14% [11–18%] at 1, 3 and 6months respectively. There were 59 deaths over a median follow‐up of 10months; 86% (n= 51) were cardiovascular (CV) deaths. Overall, the mode of death was progressive HF in 52% (n= 31), sudden death (SD) in 22% (n= 13), other CV death in 12% (n= 7), and non‐CV death in 14% (n= 8). On multivariable analysis, progressive HF deaths were associated with older age, lower serum sodium, systolic hypotension, prolonged QRS duration at baseline and absence of ACE inhibitor therapy at the time of discharge or death.

Conclusion:

Early prognosis after a new diagnosis of HF in the general population is poor and progressive HF, rather than sudden death, accounts for the majority of deaths.
Charcoal records from thermokarst deposits in central Yakutia, eastern Siberia: Implications for forest fire history and thermokarst development
Authors: Katamura Fumitaka , Fukuda Masami , Bosikov Nikolai Petrovich , Desyatkin Roman Vasilievich
Published: October 2008

Macroscopic charcoal records from a thermokarst lake deposit in central Yakutia, eastern Siberia, were used to reconstruct the history of forest fires and investigate its relationship to thermokarst initiation. High accumulation rates of charcoal and pollen were coincident in the basal deposits of the thermokarst lake, which suggests that both were initially deposited on the forest floor and subsequently reworked and accumulated in the thermokarst depression. High charcoal and pollen accumulation rates in the basal deposits, dating to 11,000–9000 cal yr BP, also indicate that the thermokarst topography developed during the early Holocene. A lower charcoal accumulation rate after ca. 9000 cal yr BP suggests that thermokarst development has been inhibited since this time. It also indicates that a surface-fire regime has been predominant at least since ca. 9000 cal yr BP in central Yakutia.
A variety of food and drink improves CVD profile
Authors: Steffen Lyn M.
Published: October 2008

An inverse association between alcohol consumption and risk of CHD in diverse populations has been reported in over forty prospective studies(1).
On the Critical Fujita Exponent for a Degenerate Parabolic System Coupled Via Nonlinear Boundary Flux
Authors: Zhou Jun , Mu Chunlai
Published: October 2008

In this paper, we deal with the non-negative solutions of a degenerate parabolic system with nonlinear coupled boundary conditions and non-negative non-trivial compactly supported initial data. The critical Fujita exponents are given and the blow-up rates of the non-global solution are obtained.
Algebraic and Geometric Theory of the Topological Ring of Colombeau Generalized Functions
Authors: Aragona J. , Juriaans S. O. , Oliveira O. R. B. , Scarpalezos D.
Published: October 2008

We continue the investigation of the algebraic and topological structure of the algebra of Colombeau generalized functions with the aim of building up the algebraic basis for the theory of these functions. This was started in a previous work of Aragona and Juriaans, where the algebraic and topological structure of the Colombeau generalized numbers were studied. Here, among other important things, we determine completely the minimal primes of and introduce several invariants of the ideals of (Ω). The main tools we use are the algebraic results obtained by Aragona and Juriaans and the theory of differential calculus on generalized manifolds developed by Aragona and co-workers. The main achievement of the differential calculus is that all classical objects, such as distributions, become C∞-functions. Our purpose is to build an independent and intrinsic theory for Colombeau generalized functions and place them in a wider context.
Spectral Theory of the Klein–Gordon Equation in Krein Spaces
Authors: Langer Heinz , Najman Branko , Tretter Christiane
Published: October 2008

In this paper the spectral properties of the abstract Klein–Gordon equation are studied. The main tool is an indefinite inner product known as the charge inner product. Under certain assumptions on the potential V, two operators are associated with the Klein–Gordon equation and studied in Krein spaces generated by the charge inner product. It is shown that the operators are self-adjoint and definitizable in these Krein spaces. As a consequence, they possess spectral functions with singularities, their essential spectra are real with a gap around 0 and their non-real spectra consist of finitely many eigenvalues of finite algebraic multiplicity which are symmetric to the real axis. One of these operators generates a strongly continuous group of unitary operators in the Krein space; the other one gives rise to two bounded semi-groups. Finally, the results are applied to the Klein–Gordon equation in ℝn.
Vector Fields Tangent to Foliations
Authors: Martins L. F. , Tari F.
Published: October 2008

We investigate in this paper the topological stability of pairs (ω, X), where ω is a germ of an integrable 1-form and X is a germ of a vector field tangent to the foliation determined by ω.
Sylow Normalizers with a Normal Sylow 2-Subgroup
Authors: Navarro Gabriel , Sanus Lucía
Published: October 2008

If G is a finite solvable group and p is a prime, then the normalizer of a Sylow p-subgroup has a normal Sylow 2-subgroup if and only if all non-trivial irreducible real 2-Brauer characters of G have degree divisible by p.
Generalized Prüfer Angle and Variational Methods for p-Laplacian Eigenvalue Problems on the Half-Line
Authors: Binding Paul , Browne Patrick J.
Published: October 2008

The nonlinear eigenvalue problem

for 0 ≤ x < ∞, fixed p ∈ (1, ∞), and with y′(0)/y(0) specified, is studied under conditions on q related to those of Brinck and Molanov. Topics include Sturmian results, connections between problems on finite intervals and the half-line, and variational principles.
Religious service attendance and spiritual well-being are differentially associated with risk of major depression
Authors: Maselko J. , Gilman S. E. , Buka S.
Published: October 2008

Background

The complex relationships between religiosity, spirituality and the risk of DSM-IV depression are not well understood.

Method

We investigated the independent influence of religious service attendance and two dimensions of spiritual well-being (religious and existential) on the lifetime risk of major depression. Data came from the New England Family Study (NEFS) cohort (n=918, mean age=39 years). Depression according to DSM-IV criteria was ascertained using structured diagnostic interviews. Odds ratios (ORs) for the associations between high, medium and low tertiles of spiritual well-being and for religious service attendance and the lifetime risk of depression were estimated using multiple logistic regression.

Results

Religious service attendance was associated with 30% lower odds of depression. In addition, individuals in the top tertile of existential well-being had a 70% lower odds of depression compared to individuals in the bottom tertile. Contrary to our original hypotheses, however, higher levels of religious well-being were associated with 1.5 times higher odds of depression.

Conclusions

Religious and existential well-being may be differentially associated with likelihood of depression. Given the complex interactions between religiosity and spirituality dimensions in relation to risk of major depression, the reliance on a single domain measure of religiosity or spirituality (e.g. religious service attendance) in research or clinical settings is discouraged.
Influence of high-frequency repetitive transcranial magnetic stimulation over the dorsolateral prefrontal cortex on the inhibition of emotional information in healthy volunteers
Authors: Leyman L. , De Raedt R. , Vanderhasselt M.-A. , Baeken C.
Published: October 2008

Background

Evidence suggests that repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) might be a promising new treatment procedure for depression. However, underlying working mechanisms of this technique are yet unclear. Multiple sessions of rTMS may – apart from the reported antidepressant effects – cause primary improvements in attentional control over emotional information, modulated by changes in cortical brain excitability within stimulated prefrontal regions.

Method

In two experiments, we examined the temporary effects of high-frequency (HF) rTMS (10 Hz) applied over the left and right DLPFC on the attentional processing of emotional information and self-reported mood within samples of healthy volunteers.

Results

The present study showed that one session of HF-rTMS over the right DLPFC produces instant impairments in the ability to inhibit negative information, in line with a characteristic cognitive vulnerability found in depressive pathology, whereas HF-rTMS of the left DLPFC did not lead to significant changes in attentional control. These effects could not be attributed to mood changes.

Conclusions

The findings of the present study may suggest a specific involvement of the right DLPFC in the attentional processing of emotional information.
Non-word repetition assesses phonological memory and is related to vocabulary development in 20- to 24-month-olds
Authors: HOFF ERIKA , CORE CYNTHIA , BRIDGES KELLY
Published: October 2008

Two studies test the hypotheses that individual differences in phonological memory among children younger than two years can be assessed using a non-word repetition task (NWR) and that these differences are related to the children's rates of vocabulary development. NWR accuracy, real word repetition accuracy and productive vocabulary were assessed in 15 children between 1 ; 9 and 2 ; 0 in Study 1 and in 21 children between 1 ; 8 and 2 ; 0 in Study 2. In both studies, NWR accuracy was significantly related to vocabulary percentile and, furthermore, uniquely accounted for a substantial portion of the variance in vocabulary when real word repetition accuracy was held constant. The findings establish NWR as a valid measure of phonological memory in very young children, and they open the door for further studies of the role of phonological memory in early word learning.