bluuebunny/crossref_metadata_2025_split huggingface dataset:
The method of the likelihood and the Fisher information in the construction of physical models
Authors: Piotrowski E.W. , Sładkowski J. , Syska J. , Zaja̧c S. 
Published: April 2009

AbstractThe subjects of the paper are the likelihood method (LM) and the expected Fisher information (FI) considered from the point od view of the construction of the physical models which originate in the statistical description of phenomena. The master equation case and structural information principle are derived. Then, the phenomenological description of the information transfer is presented. The extreme physical information (EPI) method is reviewed. As if marginal, the statistical interpretation of the amplitude of the system is given. The formalism developed in this paper would be also applied in quantum information processing and quantum game theory (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bivariate constant stress degradation model: LED lighting system reliability estimation with two‐stage modelling
Authors: Sari J. K. , Newby M. J. , Brombacher A. C. , Tang L. C. 
Published: April 2009

AbstractLight‐emitting diode (LED) lamp has received great attention as a potential replacement for the more commercially available lighting technology, such as incandescence and fluorescence lamps. LED which is the main component of LED lamp has a very long lifetime. This means that no or very few failures are expected during LED lamp testing. Therefore, degradation testing and modelling are needed. Because the complexity of modern lighting system is increasing, it is possible that more than one degradation failures dominate the system reliability. If degradation paths of the system's performance characteristics (PCs) tend to be comonotone there is a likely dependence between the PCs because of the system's common usage history. In this paper, a bivariate constant stress degradation data model is proposed. The model accommodates assumptions of dependency between PCs and allows the use of different marginal degradation distribution functions. Consequently, a better system reliability estimation can be expected from this model than from a model with independent PCs assumption. The proposed model is applied to an actual LED lamps experiment data. Copyright © 2009 John Wiley & Sons, Ltd.
Optimal Sparse Descriptor Selection for QSAR Using Bayesian Methods
Authors: Burden F. R. , Winkler D. A. 
Published: April 2009

AbstractChoosing a set of molecular descriptors (features) that is most relevant to a given biological response variable is a very important problem in QSAR that has not be solved in an optimal robust way. It is an interesting and important class of mathematical problems, where the number of variables greatly outweighs the number of observations (grossly underdetermined systems). We have used two Bayesian approaches to carry out this task using a suite of QSAR data sets. We employed a specialized sparse Bayesian feature reduction method based on an EM algorithm with a Laplacian prior to select a small set of the most relevant descriptors for modeling the response variables from a much larger pool of possibilities. Having chosen the optimum descriptors in a supervised manner, we used a Bayesian regularized neural network to carry out nonlinear regression and derive robust parsimonious QSAR models for five drug data sets. Models were validated using independent test sets, and results compared with other contemporary descriptor selection methods. Issues around validating small QSAR data sets were also discussed in detail. The sparse feature selection algorithm proved to be an excellent, robust method for selecting descriptors for QSAR models, as it is supervised (descriptors chosen in a context‐dependent manner), parsimonious (models not overly complex), and inherently interpretable. Coupled to a robust parsimonious nonlinear modeling method such as the Bayesian regularized neural net, the combination provides a means of optimally modeling the data, and allowing interpretation of the model in terms of the most relevant descriptors.
Rapid analysis of long‐chain glycolipids in heterocystous cyanobacteria using high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry
Authors: Bauersachs Thorsten , Hopmans Ellen C. , Compaoré Justine , Stal Lucas J. , Schouten Stefan , Damsté Jaap S. Sinninghe 
Published: April 2009

AbstractUnder nitrogen‐depleted conditions, N2‐fixing cyanobacteria of the order Nostocales and Stigonematales differentiate vegetative cells into heterocysts. The cell envelope of these specialized cells contains unique glycolipids, consisting of a sugar moiety glycosidically bound to long‐chain diols, triols and hydroxyketones. Only few reports have been published on these glycolipids in cultured cyanobacteria and none has reported them in natural environments. Here we show that heterocyst glycolipids can be rapidly and sensitively analyzed using high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC/ESI‐MS2). Positive ion mass spectra of the glycolipids consisted of protonated molecules and diagnostic product ions, indicating losses of sugar groups as well as hydroxyl and carbonyl functionalities from an alkyl chain. Using this method, heterocyst glycolipids were for the first time identified in a natural ecosystem, i.e., a microbial mat from the North Sea barrier island Schiermonnikoog, The Netherlands. This technique will facilitate the quick screening of cyanobacterial cultures and natural environments for the presence of heterocyst glycolipids, which may aid in assessing the role of heterocystous cyanobacteria in the global nitrogen cycle. Copyright © 2009 John Wiley & Sons, Ltd.
Correlated bivariate continuous and binary outcomes: Issues and applications
Authors: Teixeira‐Pinto Armando , Normand Sharon‐Lise T. 
Published: April 2009

AbstractIncreasingly multiple outcomes are collected in order to characterize treatment effectiveness or to evaluate the impact of large policy initiatives. Often the multiple outcomes are non‐commensurate, e.g. measured on different scales. The common approach to inference is to model each outcome separately ignoring the potential correlation among the responses. We describe and contrast several full likelihood and quasi‐likelihood multivariate methods for non‐commensurate outcomes. We present a new multivariate model to analyze binary and continuous correlated outcomes using a latent variable. We study the efficiency gains of the multivariate methods relative to the univariate approach. For complete data, all approaches yield consistent parameter estimates. When the mean structure of all outcomes depends on the same set of covariates, efficiency gains by adopting a multivariate approach are negligible. In contrast, when the mean outcomes depend on different covariate sets, large efficiency gains are realized. Three real examples illustrate the different approaches. Copyright © 2009 John Wiley & Sons, Ltd.
Beurteilung von Korrosionsschutzsystemen für Offshore‐Windenergietürme – Teil 1: Problemstellung und Versuchsdurchführung
Authors: Momber Andreas , Plagemann Peter , Stenzel Volkmar , Schneider Michael 
Published: April 2009

Abstractm Rahmen von Auslagerungs‐ und Laborprüfungen wurde die Korrosionsschutzwirkung verschiedener, für den Schutz von Offshore‐Windenergietürmen geeigneter Systeme untersucht. Zu den untersuchten Systemen gehörten Duplexsysteme mit Zn/Al‐Metallisierung, mehrschichtige organische Systeme, ein einschichtiges organisches System, eine Zn/Mg‐Metallisierung sowie unbeschichtete Bereiche mit kathodischem Korrosionsschutz. Alle Systeme wurden an speziell gefertigten Auslagerungsprobekörpern sowie an Laborprobekörpern geprüft. Die im Labormaßstab durchgeführten Prüfungen umfassten Tauchversuche, Alterungsversuche, Versuche zur kathodischen Verträglichkeit und Messungen mittels elektrochemischer Impedanzspektroskopie. Im Teil 1 des Beitrages werden Konzeption und Durchführung der Prüfungen sowie die verwendeten Probekörper und Korrosionsschutzsysteme detailliert beschrieben. Über die Ergebnisse der Prüfungen wird im Teil 2 berichtet.
Using instructional logs to identify quality in educational settings
Authors: Rowan Brian , Jacob Robin , Correnti Richard 
Published: April 2009

AbstractWhen attempting to identify educational settings that are most effective in improving student achievement, classroom process (that is, the way in which a teacher interacts with his or her students) is a key feature of interest. Unfortunately, high‐quality assessment of the student‐teacher interaction occurs all too infrequently, despite the critical role that understanding and measuring such processes can play in school improvement.This article discusses the strengths and weaknesses of two common approaches to studying these processes—direct classroom observation and annual surveys of teachers—and then describes the ways in which instructional logs can be used to overcome some of the limitations of these two approaches when gathering data on curriculum content and coverage. Classroom observations are expensive, require extensive training of raters to ensure consistency in the observations, and because of their expense generally cannot be conducted frequently enough to enable the researcher to generalize observational findings to the entire school year or illuminate the patterns of instructional change that occur across the school year. Annual surveys are less expensive but often suffer from self‐report bias and the bias that occurs when teachers are asked to retrospectively report on their activities over the course of a single year. Instructional logs offer a valid, reliable, and relatively cost‐effective alternative for collecting detailed information about classroom practice and can overcome some of the limitations of both observations and annual surveys.
Assessing after‐school settings
Authors: Grossman Jean Baldwin , Goldmith Julie , Sheldon Jessica , Arbreton Amy J. A. 
Published: April 2009

AbstractAccording to previous research, three point‐of‐service features—strong youth engagement, well‐conceived and well‐delivered content, and a conducive learning environment—lead to positive impacts in after‐school settings, the ultimate gauge of quality. To assess quality at a program's point of service, researchers and program administrators should measure indicators of these three quality features. We argue that youth engagement should be the first of these indicators to be measured because it reflects both the content of program activities and the conditions of the learning environment. Next, content should be assessed to ensure that staff deliver a well‐designed sequence of active tasks that are linked explicitly to the development of desired skills or competencies. Finally, assessing the learning environment can help explain whether youths' absorption of the content is inhibited by poor interactions, limited youth decision making, or unsafe conditions. In presenting and evaluating multiple measurement approaches, the authors argue that the most reliable measures are those collected from the agent (either youth or staff members) to whom the indicator is most directly tied. Engagement, for example, is an experience of the youth, content is delivered by staff members, and the learning environment, which is maintained by staff members and experienced by the youth, is tied to both agents. Findings from quality assessments should be used to feed an ongoing process of training, support, and content change aimed at quality improvement.
Spectroscopic and Vanadium K‐Edge EXAFS Studies on VO2Cl and the Crystal Structure of [{Cl2VO(O2PCl2)(POCl3)}2]
Authors: Hector Andrew L. , Jura Marek , Levason William , Reid Gillian , Webster Michael 
Published: April 2009

AbstractSpectroscopic and vanadium K‐edge EXAFS data on VO2Cl suggest a structure based upon a dimeric OClV(μ‐O)2VClO core linked by longer V···Cl interactions into a polymer. The crystal structure of [{Cl2VO(O2PCl2)(POCl3)}2], obtained from VO2Cland POCl3, shows a centrosymmetric dimer with bridgingPO2Cl2 groups, and terminal POCl3 ligands O‐coordinated to each vanadium atom. Cl14O8P4V2: Space group P$\bar{1}$, Z = 1, lattice dimensions at 120 K: a = 8.039(2), b = 8.1641(15), c = 10.308(3) Å, α = 92.586(15), β = 103.829(10), γ = 106.963(15)°; R1 = 0.065.
Synthesis and Characterization of β‐Diketiminate Zinc Complexes
Authors: Schulz Stephan , Eisenmann Tamara , Bläser Dieter , Boese Roland 
Published: April 2009

AbstractReactions of the monomeric β‐diketiminate zinc complex MesNacNacZnMe (MesNacNac = {[2,6‐(2,4,6‐Me3–C6H2)‐N(Me)C)]2CH}) with ROH (R = Me, Et, iPr) yielded the corresponding zinc alkoxides [MesNacNacZnOR]2 (R = Me 1, Et 2, iPr 3). In addition, the reaction of MesNacNacZnCl with various reducing agents such as potassium graphite, potassium, or sodium gave the ZnII complex [MesNacNac]2Zn 4. Compounds 1–4were characterized by elemental analyses, mass and multinuclear (1H, 13C{1H}) NMR spectroscopy, and by single‐crystal X‐ray analysis.
Bis(phosphinimino)methanides as Ligands in Divalent Ytterbium and Strontium Chemistry–Synthesis and Structure
Authors: Wiecko Michal , Marks Sebastian , Panda Tarun K. , Roesky Peter W. 
Published: April 2009

AbstractTwo new bis(phosphinimino)methanide complexes of divalent ytterbium, [{(Me3SiNPPh2)2CH}2Yb], and strontium, [{(Me3SiNPPh2)2CH}2Sr], were synthesized from the corresponding metal diiodides and of K{CH(PPh2NSiMe3)2}. Alternatively, the ytterbium compound could also be obtained starting from [{(Me3SiNPPh2)2CH}YbI(THF)2]. A comparison of the properties with the analogues compounds [{(Me3SiNPPh2)2CH}2M] (M = Ca, Ba, Sm, Eu) is given.
Lithium Intercalation into β‐Rhombohedral Boron: LiB∼10 or Li30B309?
Authors: Vojteer Natascha , Stauffer Julia , Hillebrecht Harald , Hofmann Kathrin , Panda Monalisa , Albert Barbara 
Published: April 2009

AbstractSingle phase samples of lithium‐doped β‐rhombohedral boron were synthesised by different high temperature routes.Both single crystals and crystalline powders were obtained. Characterisation was done by electron energy loss spectroscopy, energy‐dispersive X‐ray spectroscopy and X‐ray diffraction. According to the crystal structure determination based on single crystal and powder data, the phase investigated is LiB∼10. Depending on the synthesis route, LiB∼10 was found to form a compound with composition Li30B309. Further lithium intercalation is possible.
Decay of geometry for Fibonacci critical covering maps of the circle
Authors: Colli Eduardo , do Nascimento Marcio L. , Vargas Edson 
Published: April 2009

We study the growth of

Df^{n}(f(c))

when

f

is a Fibonacci critical covering map of the circle with negative Schwarzian derivative, degree

d⩾2

and critical point

c

of order

ℓ > 1

. As an application we prove that

f

exhibits exponential decay of geometry if and only if

ℓ⩽2

, and in this case it has an absolutely continuous invariant probability measure, although not satisfying the so-called Collet–Eckmann condition.

Résumé

Nous étudions la croissance de

Df^{n}(f(c))

lorsque

f

est un revêtement critique de Fibonacci du cercle avec dérivée Schwarzienne négative, degré

d⩾2

et point critique

c

d'ordre

ℓ > 1

. Comme application nous démontrons que

f

exhibe une décroissance exponentielle de géométrie si et seulement si

ℓ⩽2

, et dans ce cas

f

a une mesure de probabilité invariante absolument continue, sans satisfaire la condition de Collet–Eckmann.
The lifespan of spherically symmetric solutions of the compressible Euler equations outside an impermeable sphere
Authors: Godin Paul 
Published: April 2009

We consider smooth three-dimensional spherically symmetric Eulerian flows of ideal polytropic gases outside an impermeable sphere, with initial data equal to the sum of a constant flow with zero velocity and a smooth perturbation with compact support. Under a natural assumption on the form of the perturbation, we obtain precise information on the asymptotic behavior of the lifespan as the size of the perturbation tends to 0. When there is no sphere, so that the flow is defined in all space, corresponding results have been obtained in [P. Godin, The lifespan of a class of smooth spherically symmetric solutions of the compressible Euler equations with variable entropy in three space dimensions, Arch. Ration. Mech. Anal. 177 (2005) 479–511].

Résumé
Nous considérons des écoulements eulériens tridimensionnels lisses à symétrie sphérique de gaz parfaits polytropiques à l'extérieur d'une sphère imperméable, avec des données initiales somme d'un écoulement constant de vitesse nulle et d'une perturbation lisse à support compact. Sous une hypothèse naturelle sur la forme de la perturbation, nous obtenons une information précise sur le comportement asymptotique de la durée de vie quand la taille de la perturbation tend vers 0. S'il n'y a pas de sphère, de sorte que l'écoulement est défini dans tout l'espace, des résultats correspondants ont été obtenus dans [P. Godin, The lifespan of a class of smooth spherically symmetric solutions of the compressible Euler equations with variable entropy in three space dimensions, Arch. Ration. Mech. Anal. 177 (2005) 479–511].
Effect of cesarean delivery on the endometrium
Authors: Ben‐Nagi Jara , Walker Amy , Jurkovic Davor , Yazbek Joseph , Aplin John D. 
Published: April 2009

AbstractObjectiveTo compare endometrial tissue samples from cesarean scar (CS) sites and from the posterior uterine wall to better understand the pathophysiology of implantation into a CS.MethodsEndometrial samples were taken from both a CS site and the posterior wall in premenopausal women with CSs, and from the posterior wall in premenopausal women who had spontaneous vaginal deliveries (SVDs) only.ResultsIn the secretory phase, there were significantly fewer leukocytes at CS sites than in the endometrium of women who had SVDs only (P < 0.05). Significant differences in leukocytic infiltration and cell proliferation between the proliferative and secretory phases were only found in women who had SVDs only (P < 0.05).ConclusionLeukocyte recruitment to the endometrium during the secretory phase may be affected by the presence of a CS.
SOLUTIONS TO PSEUDODIFFERENTIAL EQUATIONS USING SPHERICAL RADIAL BASIS FUNCTIONS
Authors: PHAM T. D. , TRAN T. 
Published: April 2009

AbstractSpherical radial basis functions are used to define approximate solutions to pseudodifferential equations of negative order on the unit sphere. These equations arise from geodesy. The approximate solutions are found by the collocation method. A salient feature of our approach in this paper is a simple error analysis for the collocation method using the same argument as that for the Galerkin method.
CCAAT/enhancer-binding protein β: its role in breast cancer and associations with receptor tyrosine kinases
Authors: Zahnow Cynthia A. 
Published: April 2009

AbstractThe CCAAT/enhancer-binding proteins (C/EBPs) are a family of leucine-zipper transcription factors that regulate gene expression to control cellular proliferation, differentiation, inflammation and metabolism. Encoded by an intronless gene, C/EBPβ is expressed as several distinct protein isoforms (LAP1, LAP2, LIP) whose expression is regulated by the differential use of several in-frame translation start sites. LAP1 and LAP2 are transcriptional activators and are associated with differentiation, whereas LIP is frequently elevated in proliferative tissue and acts as a dominant-negative inhibitor of transcription. However, emerging evidence suggests that LIP can serve as a transcriptional activator in some cellular contexts, and that LAP1 and LAP2 might also have unique actions. The LIP:LAP ratio is crucial for the maintenance of normal growth and development, and increases in this ratio lead to aggressive forms of breast cancer. This review discusses the regulation of C/EBPβ activity by post-translational modification, the individual actions of LAP1, LAP2 and LIP, and the functions and downstream targets that are unique to each isoform. The role of the C/EBPβ isoforms in breast cancer is discussed and emphasis is placed on their interactions with receptor tyrosine kinases.
Thermodynamic characterization of the redox centres in a representative domain of a novel c-type multihaem cytochrome
Authors: Morgado Leonor , Fernandes Ana P. , Londer Yuri Y. , Pokkuluri P. Raj , Schiffer Marianne , Salgueiro Carlos A. 
Published: April 2009

Multihaem cytochromes that could form protein “nanowires” were identified in the Geobacter sulfurreducens genome, and represent a new type of multihaem cytochrome. The sequences of these proteins, two with 12 haems (GSU1996, GSU0592) and one with 27 haems (GSU2210), suggest that they are formed with domains homologous to the trihaem cytochrome c7. Although all three haems have bis-His co-ordination in cytochromes c7, in each domain of the above polymers, the haem equivalent to haem IV has His-Met co-ordination. We previously determined the structure and measured the macroscopic redox potential of one representative domain (domain C) of a dodecahaem cytochrome (GSU1996). In the present study, the microscopic redox properties of the individual haem groups of domain C were determined using NMR and UV–visible spectroscopies. The reduction potentials of the haems for the fully reduced and protonated protein are different from each other (haem I, −106 mV; haem III, −136 mV; and haem IV, −125 mV) and are strongly modulated by redox interactions. This result is rather surprising since the His-Met co-ordinated haem IV does not have the highest potential as was expected. The polypeptide environment of each haem group and the strong haem pairwise redox interactions must play a dominant role in controlling the individual haem potentials. The strong redox interactions between the haems extend the range of their operating potentials at physiological pH (haem I, −71 mV, haem III, −146 mV and haem IV, −110 mV). Such a modulation in haem potentials is likely to have a functional significance in the metabolism of G. sulfurreducens.
Plasma apelin concentration is depressed following acute myocardial infarction in man
Authors: Weir Robin A.P. , Chong Kwok Shiong , Dalzell Jonathan R. , Petrie Colin J. , Murphy Charles A. , Steedman Tracey , Mark Patrick B. , McDonagh Theresa A. , Dargie Henry J. , McMurray John J.V. 
Published: April 2009

AimsApelin, a novel peptide with a putative role in cardiovascular homeostasis, has gained interest as an endogenous inotrope, but has yet to be described following acute myocardial infarction (AMI) in man. We aimed to characterize plasma apelin concentrations following AMI and to examine its relationship with clinical and prognostic biomarkers.Methods and resultsPlasma concentrations of apelin, N‐terminal probrain natriuretic peptide (NT‐proBNP), norepinephrine, and arginine vasopressin were measured in 100 patients [mean age 58.9 ± 12 (SD) years, 77% male] admitted with AMI, with echocardiographic left ventricular (LV) ejection fraction <40%, at mean 46 h after admission and at 24 weeks. Cardiac magnetic resonance imaging was performed pre‐discharge and at 24 weeks. Thirty‐eight subjects with no cardiac history acted as controls. Apelin concentration was reduced early after AMI (0.54 ± 0.25 vs. 3.22 ± 3.01 ng/mL, P <0.001) and remained low at 24 weeks, although it did increase significantly from baseline to 0.62 ± 0.36 ng/mL, P = 0.030. Apelin had no relationship with any parameter of LV function over time. A relationship was found between baseline apelin and norepinephrine (r = 0.26, P = 0.008). Both NT‐proBNP and norepinephrine correlated with adverse ventricular function after AMI.ConclusionPlasma apelin concentration is reduced early after AMI, increases significantly over time, but remains depressed at 24 weeks.