bluuebunny/crossref_metadata_2025_split huggingface dataset:
Struktur- und Parameteridentifikation mit Evolutionären Algorithmen
Authors: Braun Jan , Krettek Johannes , Hoffmann Frank , Bertram Torsten , Lausch Horst , Schoppel Georg 
Published: May 2011

Zusammenfassung
Modellierung und Identifikation dynamischer Systeme sind wichtige Aspekte der Regelungstechnik. Dieser Beitrag stellt einen Ansatz zur Optimierung von strukturvariablen Modellen dynamischer Systeme mit multikriteriellen evolutionären Algorithmen vor. Die Methode verwendet spezifische evolutionäre Operatoren zur simultanen Optimierung der Struktur eines Modells und ihrer Parameter. Basierend auf Ein- und Ausgangsdaten des realen Systems ermittelt die Strategie eine Menge von optimalen Modellen, die einen Kompromiss zwischen Qualität und Komplexität der Modellierung darstellen. Exemplarisch angewandt wird das Verfahren für die Identifikation eines künstlichen Testsystems sowie eines hydraulischen Proportionalventils und eines elastischen Roboterarms.
Expansions for the risk of Stein type estimates for non-normal data
Authors: Withers Christopher S. , Nadarajah Saralees 
Published: May 2011

Abstract
We consider the James–Stein problem for non-normal data for estimating a p-vector

θ

. It is shown how the risk may be expanded in powers of p
-1
. The factor 1-2/p that distinguishes the James–Stein estimate from the Stein estimate is shown to have only O(p
-2) effect on the risk. The case, where the variance must be estimated is studied for the one-way unbalanced ANOVA problem.
Mean-risk tests of stochastic dominance
Authors: Dentcheva Darinka , Stock Gregory J. , Rekeda Ludmyla 
Published: May 2011

Abstract
We propose a new approach to testing whether one random variable is stochastically non-dominated by another one. The tests compare mean-risk differences of two unknown distributions using independent samples. The test can be used for comparison of the coherent risk measures of the distributions, as well as to reject stochastic dominance relation of first, second, or higher order between the two distributions. We consider several law-invariant coherent measures of risk which are consistent with the stochastic dominance relation of first and higher order. Numerical comparisons with the Mann–Whitney test and with the F-test for comparison of variance are provided. The numerical study indicates that most of the mean-risk tests are more powerful than the Mann–Whitney test.
Non-parametric drift estimation for diffusions from noisy data
Authors: Schmisser Emeline 
Published: May 2011

Abstract
Consider a diffusion process (X

t
)
t ≥ 0, with unknown drift b(x) and diffusion coefficient σ(x), which is strictly stationary, ergodic and β-mixing. At discrete times t

k
= k
δ for k from 1 to N, we have at disposal noisy data of the sample path, Y

k
δ
= X

k
δ
+ε

k
. The random variables (ε

k
) are i.i.d., centred and independent of (X

t
). In order to reduce the noise effect, we split data into groups of equal size p and build empirical means. The group size p is chosen such that Δ = p
δ is small whereas N
δ is large. Then, the drift function b is estimated in a compact set A in a non-parametric way using a penalized least squares approach. We obtain a bound for the risk of the resulting adaptive estimator. Examples of diffusions satisfying our assumptions are given and numerical simulation results illustrate the theoretical properties of our estimators.
Comparison of Markov processes via infinitesimal generators
Authors: Rüschendorf Ludger , Wolf Viktor 
Published: May 2011

Abstract
We derive comparison results for Markov processes with respect to stochastic orderings induced by function classes. Our main result states that stochastic monotonicity of one process and comparability of the infinitesimal generators implies ordering of the processes. Unlike in previous work no boundedness assumptions on the function classes are needed anymore. We also present an integral version of the comparison result which does not need the local comparability assumption of the generators. The method of proof is also used to derive comparison results for time-discrete Markov processes.
Bestimmung der Messunsicherheit am Beispiel einer Magnetfeldmessung
Authors: Ihlenburg Lutz , Heinze Hartmut 
Published: May 2011

Zusammenfassung
Mit dem Leitfaden GUM (Guide to the Expression of Uncertainty in Measurement) bzw. der deutschen Vornorm DIN V ENV 13005 (Leitfaden zur Angabe der Unsicherheit beim Messen) ist ein Rahmen gesetzt, Messunsicherheiten international vergleichbar zu beschreiben. Am Beispiel wird gezeigt, wie sich aus Datenblättern die Messunsicherheit nach deren Regeln ermittelt lässt.
Piezoelektrische Polyvinylidenfluorid — Folien zur Messung bruchmechanischer Kenngrößen
Authors: Bäcker Dennis , Häusler Christoph , Kuna Meinhard 
Published: May 2011

Zusammenfassung
Es wird eine Methode zur gleichzeitigen Messung der Rissspitzenlage und der Spannungsintensitätsfaktoren (SIF) von Rissen in dünnwandigen ebenen oder gekrümmten Strukturen bei Ermüdungsrisswachstum vorgestellt. Voraussetzung hierbei ist, dass die Strukturen aus einem isotropen und dem Konzept des Sprödbruchs gehorchenden Material bestehen. Für die Messung wird eine orthotrope piezoelektrische Polyvinylidenfluorid Folie (PVDF-Folie) auf den rissbehafteten Bereich der Struktur appliziert. Die elektrischen Signale der piezoelektrischen Folie sind ein Maß für die Lage und Belastung des Risses. Die Bestimmung der Risslage und SIF aus den elektrischen Signalen erfolgt durch das Lösen des sich ergebenden inversen Problems. Die Messmethode wird am Beispiel des Griffith-Risses hypothetisch erprobt. Im Gegensatz zu der vorausgehenden Publikation [1] gelingt nun neben der genauen Bestimmung des K
I-Faktors auch die des K
II-Faktors.
Einfluss nichtlinearer Kennlinien auf die Fehlerfortpflanzung EA-linearisierter Messketten
Authors: Mareczek Jörg 
Published: May 2011

Zusammenfassung
Für Eingang-Ausgang-linearisierte Messketten mit unsicheren Parametern und nichtlinearen Kennlinien wird eine analytische und trotzdem übersichtliche Form des Messfehlers hergeleitet. Pro Teilsystem besteht diese aus nur einem Parameter-Perturbations-Term und einer Linearitätsabweichung. Damit wird der Einfluss der Nichtlinearitäten auf die Fehlerfortpflanzung ohne aufwändige Rechnungen möglich. Um eine Fehlergrenze einzuhalten, können so bereits im Systementwurf die Kennlinienformen eingehen. Dies stellt eine möglicherweise kostengünstigere und einfachere Alternative zur Reduzierung von Toleranzen dar.
The Relation Between Reproductive Value and Genetic Contribution
Authors: Barton Nicholas H , Etheridge Alison M 
Published: May 2011

Abstract
What determines the genetic contribution that an individual makes to future generations? With biparental reproduction, each individual leaves a “pedigree” of descendants, determined by the biparental relationships in the population. The pedigree of an individual constrains the lines of descent of each of its genes. An individual’s reproductive value is the expected number of copies of each of its genes that is passed on to distant generations conditional on its pedigree. For the simplest model of biparental reproduction (analogous to the Wright–Fisher model), an individual’s reproductive value is determined within ∼10 generations, independent of population size. Partial selfing and subdivision do not greatly slow this convergence. Our central result is that the probability that a gene will survive is proportional to the reproductive value of the individual that carries it and that, conditional on survival, after a few tens of generations, the distribution of the number of surviving copies is the same for all individuals, whatever their reproductive value. These results can be generalized to the joint distribution of surviving blocks of the ancestral genome. Selection on unlinked loci in the genetic background may greatly increase the variance in reproductive value, but the above results nevertheless still hold. The almost linear relationship between survival probability and reproductive value also holds for weakly favored alleles. Thus, the influence of the complex pedigree of descendants on an individual’s genetic contribution to the population can be summarized through a single number: its reproductive value.
Insight Into the Mechanism of Nucleosome Reorganization From Histone Mutants That Suppress Defects in the FACT Histone Chaperone
Authors: McCullough Laura , Rawlins Robert , Olsen Aileen , Xin Hua , Stillman David J , Formosa Tim 
Published: May 2011

Abstract
FACT (FAcilitates Chromatin Transcription/Transactions) plays a central role in transcription and replication in eukaryotes by both establishing and overcoming the repressive properties of chromatin. FACT promotes these opposing goals by interconverting nucleosomes between the canonical form and a more open reorganized form. In the forward direction, reorganization destabilizes nucleosomes, while the reverse reaction promotes nucleosome assembly. Nucleosome destabilization involves disrupting contacts among histone H2A-H2B dimers, (H3-H4)2 tetramers, and DNA. Here we show that mutations that weaken the dimer:tetramer interface in nucleosomes suppress defects caused by FACT deficiency in vivo in the yeast Saccharomyces cerevisiae. Mutating the gene that encodes the Spt16 subunit of FACT causes phenotypes associated with defects in transcription and replication, and we identify histone mutants that selectively suppress those associated with replication. Analysis of purified components suggests that the defective version of FACT is unable to maintain the reorganized nucleosome state efficiently, whereas nucleosomes with mutant histones are reorganized more easily than normal. The genetic suppression observed when the FACT defect is combined with the histone defect therefore reveals the importance of the dynamic reorganization of contacts within nucleosomes to the function of FACT in vivo, especially to FACT’s apparent role in promoting progression of DNA replication complexes. We also show that an H2B mutation causes different phenotypes, depending on which of the two similar genes that encode this protein are altered, revealing unexpected functional differences between these duplicated genes and calling into question the practice of examining the effects of histone mutants by expressing them from a single plasmid-borne allele.
Genetic Draft and Quasi-Neutrality in Large Facultatively Sexual Populations
Authors: Neher R A , Shraiman B I 
Published: May 2011

Abstract
Large populations may contain numerous simultaneously segregating polymorphisms subject to natural selection. Since selection acts on individuals whose fitness depends on many loci, different loci affect each other’s dynamics. This leads to stochastic fluctuations of allele frequencies above and beyond genetic drift—an effect known as genetic draft. Since recombination disrupts associations between alleles, draft is strong when recombination is rare. Here, we study a facultatively outcrossing population in a regime where the frequency of outcrossing and recombination, r, is small compared to the characteristic scale of fitness differences σ. In this regime, fit genotypes expand clonally, leading to large fluctuations in the number of recombinant offspring genotypes. The power law tail in the distribution of the latter makes it impossible to capture the dynamics of draft by an effective neutral model. Instead, we find that the fixation time of a neutral allele increases only slowly with the population size but depends sensitively on the ratio r/σ. The efficacy of selection is reduced dramatically and alleles behave “quasi-neutrally” even for Ns≫1, provided that |s| &lt; sc, where sc depends strongly on r/σ, but only weakly on population size N. In addition, the anomalous fluctuations due to draft change the spectrum of (quasi)-neutral alleles from f(ν) ∼ ν−1, corresponding to drift, to ∼ ν−2. Finally, draft accelerates the rate of two-step adaptations through deleterious intermediates.
Regulation of Conidiation by Light in Aspergillus nidulans
Authors: Ruger-Herreros Carmen , Rodríguez-Romero Julio , Fernández-Barranco Raul , Olmedo María , Fischer Reinhard , Corrochano Luis M , Canovas David 
Published: May 2011

Abstract
Light regulates several aspects of the biology of many organisms, including the balance between asexual and sexual development in some fungi. To understand how light regulates fungal development at the molecular level we have used Aspergillus nidulans as a model. We have performed a genome-wide expression analysis that has allowed us to identify &gt;400 genes upregulated and &gt;100 genes downregulated by light in developmentally competent mycelium. Among the upregulated genes were genes required for the regulation of asexual development, one of the major biological responses to light in A. nidulans, which is a pathway controlled by the master regulatory gene brlA. The expression of brlA, like conidiation, is induced by light. A detailed analysis of brlA light regulation revealed increased expression after short exposures with a maximum after 60 min of light followed by photoadaptation with longer light exposures. In addition to brlA, genes flbA–C and fluG are also light regulated, and flbA–C are required for the correct light-dependent regulation of the upstream regulator fluG. We have found that light induction of brlA required the photoreceptor complex composed of a phytochrome FphA, and the white-collar homologs LreA and LreB, and the fluffy genes flbA–C. We propose that the activation of regulatory genes by light is the key event in the activation of asexual development by light in A. nidulans.
Sports Drinks and Energy Drinks for Children and Adolescents: Are They Appropriate?
Authors: Schneider Marcie Beth , Benjamin Holly J. ,   Committee on Nutrition and the Council on Sports Medicine and Fitness
Published: May 2011

This Clinical Report was retired July 2021.
Sports and energy drinks are being marketed to children and adolescents for a wide variety of inappropriate uses. Sports drinks and energy drinks are significantly different products, and the terms should not be used interchangeably. The primary objectives of this clinical report are to define the ingredients of sports and energy drinks, categorize the similarities and differences between the products, and discuss misuses and abuses. Secondary objectives are to encourage screening during annual physical examinations for sports and energy drink use, to understand the reasons why youth consumption is widespread, and to improve education aimed at decreasing or eliminating the inappropriate use of these beverages by children and adolescents. Rigorous review and analysis of the literature reveal that caffeine and other stimulant substances contained in energy drinks have no place in the diet of children and adolescents. Furthermore, frequent or excessive intake of caloric sports drinks can substantially increase the risk for overweight or obesity in children and adolescents. Discussion regarding the appropriate use of sports drinks in the youth athlete who participates regularly in endurance or high-intensity sports and vigorous physical activity is beyond the scope of this report.
Creating an Inexpensive 3D Printer to Engage Students in Material Science Education
Authors: Muskin Joseph J. , Davis Kathleen M. 
Published: May 2011

ABSTRACTMaterial science can be used to enrich secondary school curriculum and illuminate for students the connection between science and technology. Based on materials research being conducted at the University of Illinois, we have developed an interdisciplinary activity that integrates engineering with chemistry and material science.Students investigate the behaviors of polymers by creating 3-dimensional (3-D) objects. Students can design objects that they “print” on the order of a cubic inch in about 20 minutes. The process students use to create these objects shows the application of engineering to material science in a novel and engaging way.A photoactive chemical is initiated by the UV and blue light emitted from a data projector. This causes the formation of free radicals, which interact with molecules of a monomer and cause a polymerization reaction. The visual result of this reaction is that a liquid solidifies where students shine light. With black-and-white images, a data projector can direct the light to form any shape. This process can be easily modified to create true 3-D objects by adding another layer of the liquid to the top of the object and then shining the light again. With about 20 dollars worth of supplies from a hardware store, a simple staging device can be created to greatly simplify the process to create a 3-D printer in the classroom. Fabrication of this device can be done by students because the projector controls the x and y array of pixels; the object only needs to move in the z direction, unlike traditional rapid prototyping machines which control movement in the x, y, and z directions.Results of integration into high school and college curriculum are discussed, and methods of integration and student perceptions of the activity are reported.
Structural and Interfacial Characteristics of thin (<10 nm) SiO2 Films Grown by Electron Cyclotron Resonance Plasma Oxidation on [100] Si Substrates
Authors: Nguyen Tai D. , Carl D. A. , Hess D. W. , Lieberman M. A. , Gronsky R. 
Published: May 2011

ABSTRACTThe feasibility of fabricating ultra-thin SiO2 films on the order of a few nanometer thickness has been demonstrated. SiO2 thin films of approximately 7 nm thickness have been produced by ion flux-controlled Electron Cyclotron Resonance plasma oxidation at low temperature on [100] Si substrates, in reproducible fashion. Electrical measurements of these films indicate that they have characteristics comparable to those of thermally grown oxides. The thickness of the films was determined by ellipsometry, and further confirmed by crosssectional High-Resolution Transmission Electron Microscopy. Comparison between the ECR and the thermal oxide films shows that the ECR films are uniform and continuous over at least a few microns in lateral direction, similar to the thermal oxide films grown at comparable thickness. In addition, HRTEM images reveal a thin (1–1.5 nm) crystalline interfacial layer between the ECR film and the [100] substrate. Thinner oxide films of approximately 5 nm thickness have also been attemped, but so far have resulted in nonuniform coverage. Reproducibility at this thickness is difficult to achieve.
The Effect of Smoking on Periodontal Bone Regeneration: A Systematic Review and Meta‐Analysis
Authors: Patel Rupal A. , Wilson Ron F. , Palmer Richard M. 
Published: May 2011

Background: The effect of smoking on soft tissues after periodontal treatment has been extensively studied. However, little focus has been placed on the impact of smoking on bone regeneration after treatment. The aim of this review is to systematically assess the effect of smoking on bone regeneration after periodontal treatment.Methods: A protocol was established and studies were sourced from five electronic databases. Screening, data abstraction, and quality assessment was conducted by two review authors. Prospective and retrospective clinical studies assessing bone regeneration in smokers and non‐smokers after periodontal therapy were selected. In addition, arms of clinical trials comparing different interventions that reported results separately for smokers and non‐smokers were also included. Primary outcome measures were based on clinical and/or radiographic indicators of bone regeneration after periodontal therapy. The review and meta‐analysis followed many of the recommendations outlined in the preferred reporting items for systematic reviews and meta‐analyses statement.Results: Six of 10 studies included in this review concluded that smoking negatively influenced bone regeneration. A meta‐analysis of a subgroup of three studies demonstrated that smoking resulted in significantly less bone gain (P = 0.03) as measured by a change in the probing bone level after the treatment of intrabony defects with guided tissue regeneration. The meta‐analysis showed a standardized mean difference of −2.05 (95% confidence interval: −2.64 to −1.47) using the random‐effects model.Conclusions: Smoking has a negative effect on bone regeneration after periodontal treatment. Patients should be advised that their smoking habit may result in poorer bone regeneration after periodontal treatment.
Periodontal Nitric Oxide Pathway Alteration Due to Precompetition Anxiety in Handball Players
Authors: Ulkar Bulent , Elgun Serenay , Ozmeric Nurdan , Özdemir Burcu , Boynueğri Duygu 
Published: May 2011

Background: Psychologic and physical stress is known to be related with periodontal disorders. The objective of this study is to investigate salivary and gingival crevicular fluid (GCF) nitric oxide (NO) metabolism and its association with the periodontal reaction to precompetition anxiety in competitive athletes.Methods: A total of 18 elite male handball players participated in this study. The anxiety level of participants was determined by using a competitive state anxiety inventory‐2 (CSAI‐2). Periodontal clinical measurements, saliva, and GCF samples were obtained before the application of the CSAI‐2 during the half‐season break and just before the league championship match. NO‐level, arginase, and NO synthase (NOS) activities were analyzed in saliva samples; NO and basic fibroblast growth factor (FGF‐b) levels were analyzed in GCF samples.Results: The CSAI‐2 was significantly different between the two evaluation time points. GCF NO and FGF‐b levels increased before the championship match, whereas saliva levels did not change. The plaque index and gingival index (GI) increased at the evaluation just before the championship match. The difference in the GI was statistically significant.Conclusion: The competitive stress of athletes may lead to a gingival/periodontal disturbance accompanied by an altered NO metabolism in saliva and GCF.
Camallanus Railliet et Henry, 1915 (Nematoda, Camallanidae) from Australian freshwater turtles with descriptions of two new species and molecular differentiation of known taxa
Authors: Kuzmin Yuriy , Tkach Vasyl , Snyder Scott , Bell Jeffrey 
Published: May 2011

AbstractTwo new species of Camallanus are described from Australian freshwater turtles. Camallanus beveridgei sp. nov. is reported from Elseya dentata in Northern Territory. It differs from other species of the genus parasitic in turtles by several characters including the shape of the median ridge in the buccal capsule and the position of the anterior pair of caudal papillae in males. Camallanus sprenti sp. nov. is reported from Elseya latisternum (type host) and Emydura krefftii in northern Queensland. It is closely related to Camallanus tuckeri, and differs from the latter species in possessing a shorter oesophagus. We summarize data on morphology, distribution and specificity of 5 known Camallanus spp. from Australian turtles and provide a key for their identification. Sequence comparison of more than 500 base pairs at the 5′ end of the nuclear 28S rDNA gene confirms the status of C. sprenti and C. beveridgei as new species. Camallanus sprenti differs from the other 4 species of Camallanus from Australian turtles by 16–59 bases (3.1–11.5%) while C. beveridgei differed from the other 4 species by 23–60 bases (4.5–11.6%). Phylogenetic analysis demonstrates close interrelationships among C. tuckeri, C. sprenti and C. beveridgei, the three species with most similar buccal capsules.