bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting risk for large‐for‐gestational age neonates at term: a population‐based Bayesian theorem study
Authors: Lindell G. , Maršál K. , Källén K. 
Published: March 2013

ABSTRACTObjectivesTo evaluate the prediction of large‐for‐gestational age (LGA) term neonates using the routine third‐trimester ultrasound examination and to investigate whether the prediction could be further improved by adding information on maternal characteristics.MethodsInformation on 56 792 singleton term pregnancies with a routine ultrasound examination at 32–34 weeks' gestation was retrieved from a population‐based perinatal register. Estimated fetal weights (FW) were expressed as gestational age‐specific standard deviation scores (Z‐scores). The prediction of LGA was assessed by receiver–operating characteristics (ROC) curves, with LGA defined as birth weight Z‐score > + 2. The data set with complete clinical information (n = 48 809) was divided into a development and a validation set. Using the development set, multiple logistic regression analysis was performed to identify maternal characteristics associated with LGA. The odds ratios obtained were converted into likelihood ratios. These were then applied to the validation set and the probability for LGA for each infant was estimated using the Bayesian theorem.ResultsThe FW Z‐score showed a high predictive ability for LGA (area under the ROC curve (AUC) 0.89 (95% CI, 0.89–0.90)). Prediction was further improved by using the model that included both FW Z‐scores and maternal variables (AUC 0.91 (95% CI, 0.90–0.92)) (P for difference < 10–6). The corresponding AUC for a model including maternal characteristics only was 0.74 (95% CI, 0.73–0.76).ConclusionsRoutine third‐trimester ultrasound FW estimation is effective in the prediction of LGA neonates at term. The prediction of LGA might be further improved by using a model including maternal characteristics. Copyright © 2013 ISUOG. Published by John Wiley & Sons, Ltd.
Structure and Polymorphism of M(thd)3 (M = Al, Cr, Mn, Fe, Co, Ga, and In)
Authors: Ahmed Mohammed A. K. , Fjellvåg Helmer , Kjekshus Arne , Wragg David S. 
Published: March 2013

AbstractFormation, crystal structure, polymorphism, and transition between polymorphs are reported for M(thd)3, (M = Al, Cr, Mn, Fe, Co, Ga, and In) [(thd)– = anion of H(thd) = C11H20O2 = 2, 2, 6, 6‐tetramethylheptane‐3, 5‐dione]. Fresh crystal‐structure data are provided for monoclinic polymorphs of Al(thd)3, Ga(thd)3, and In(thd)3. Apart from adjustment of the M–Ok bond length, the structural characteristics of M(thd)3 complexes remain essentially unaffected by change of M. Analysis of the M–Ok, Ok–Ck, and Ck–Ck distances support the notion that the M–Ok–Ck–Ck–Ck–Ok– ring forms a heterocyclic unit with σ and π contributions to the bonds. Tentative assessments according to the bond‐valence or bond‐order scheme suggest that the strengths of the σ bonds are approximately equal for the M–Ok, Ok–Ck, and Ck–Ck bonds, whereas the π component of the M–Ok bonds is small compared with those for the Ok–Ck, and Ck–Ck bonds. The contours of a pattern for the occurrence of M(thd)3 polymorphs suggest that polymorphs with structures of orthorhombic or higher symmetry are favored on crystallization from the vapor phase (viz. sublimation). Monoclinic polymorphs prefer crystallization from solution at temperatures closer to ambient. Each of the M(thd)3 complexes subject to this study exhibits three or more polymorphs (further variants are likely to emerge consequent on systematic exploration of the crystallization conditions). High‐temperature powder X‐ray diffraction shows that the monoclinic polymorphs convert irreversibly to the corresponding rotational disordered orthorhombic variant above some 100–150 °C (depending on M). The orthorhombic variant is in turn transformed into polymorphs of tetragonal and cubic symmetry before entering the molten state. These findings are discussed in light of the current conceptions of rotational disorder in molecular crystals.
1,1‐Carboboration of Dialkynyltin Compounds using Tri­organoboranes of Greatly Different Lewis Acid Strength. 1,4‐Stannabora‐cyclohexa‐2,5‐dienes and Characterization of Zwitterionic Intermediates
Authors: Wrackmeyer Bernd , Thoma Peter , Marx Simone , Glatz Germund , Kempe Rhett 
Published: March 2013

AbstractAbstract. Triorganoboranes BR3, Et‐9‐BBN, BPh3, and B(C6F5)3, were compared in their reactivity towards various dialkynyl(diorgano)tin compounds (R12Sn(C≡C–R2)2 with R12 = –(CH2)5–, R2 = H (a), R1 = nBu, R2 = H (b), R1 = Ph, R2 = H (c), R1 = R2 = nBu (d)). 1,1‐Carboboration took place readily in two consecutive steps (inter‐ and intramolecular), leading either to stannoles or to 1,4‐stannabora‐cyclohexa‐2,5‐dienes, or mixtures thereof. The weakest Lewis‐acidic triorganoboranes BEt3 and Et‐9‐BBN afford selectively stannoles with diethynyltin compounds, whereas the strongly electrophilic B(C6F5)3 leads selectively to 1,4‐stannabora‐cyclohexa‐2,5‐dienes for all dialkynyltin compounds studied. In several cases, zwitterionic intermediates could be detected by multinuclear magnetic resonance spectroscopy (1H, 11B, 13C, and 119Sn NMR), and the molecular structure of such an intermediate as well as that of the final product, an 1,4‐stannabora‐cyclohexa‐2,5‐diene, could be determined by X‐ray crystallography.
Solvent‐dependent Switch of Magnesium Ions between Different Binding Sites in a Compartmental Schiff Base Ligand
Authors: Coleman Fergal , Dux Dinah , Erxleben Andrea 
Published: March 2013

AbstractThe coordination behavior of two Schiff base ligands, N,N′‐bis(3‐carboxysalicylidene)ethylenediamine (H2L1) and N,N′‐bis(3‐carboxysalicylidene)propylenediamine (H2L2), towards magnesium ions is reported. The ligands show different binding site selectivity for Mg2+ depending on the solvent. In complexes isolated from aqueous or methanolic solutions the metal ion resides in the outer O2O2 compartment. The X‐ray analysis of the complex of H2L1 showed the complex to be dimeric with magnesium being coordinated by two phenolate and two carboxylate oxygens, a bridging phenolate oxygen, and a water ligand. In aprotic solvents like dimethylsulfoxide (DMSO) and dimethylformamide (DMF) magnesium migrates to the inner N2O2 binding site. In DMSO solution containing small amounts of water, both isomers co‐exist. A similar solvent‐dependent site selectivity is not observed for zinc ions.
Top management teams and the performance of entrepreneurial firms
Authors: Eisenhardt Kathleen M. 
Published: March 2013

Abstract
This article examines why some entrepreneurial firms succeed while others do not. The focal explanation is top management teams, including several studies that address when and how top management teams are likely to influence entrepreneurial firm performance. There are several insights. First, large and diverse teams with a history of working together are more likely to succeed. This effect is particularly large when they launch in growth markets. Second, teams are effective in making strategic decisions when they are fast, highly conflictual, and still get along. Third, they are also effective when they rely on “simple rules” heuristics to perform significant activities like new product development and internationalization that nonetheless happens often. A further insight is that these “simple rules” can become the strategy of their firms. Fourth, more effective teams continuously organize the structures of their firms at the “edge of chaos”. Overall, top management teams emerge as central to the success (or lack thereof) of entrepreneurial firms.
Synthesis of Chloro Alkoxy and Alkoxy Derivatives of Methyl Oleate
Authors: Lowery Benjamin A. , Andersh Brad , Isbell Terry A. 
Published: March 2013

AbstractVegetable oil based lubricants typically have improved lubricity and biodegradability over their mineral oil based counterparts. However, vegetable oil lubricants often fail to meet the performance standards of mineral based oils with respect to cold temperature and resistance to oxidation. Olefins are an oxidatively weak point for vegetable based compounds. Removal of the olefin in a vegetable based lubricant through functionalization may increase resistance to oxidation. If the added functionality also causes branching of the alkyl chain, cold temperature properties may be improved. Any chemical modifications considered must be scalable and cost‐effective to be useful in a commercial application. In this study, methyl oleate was functionalized into a chloro alkoxy derivative. Sodium hypochlorite (household bleach) and calcium hypochlorite were both used to generate hypochlorous acid in situ. Hypochlorous acid and a series of alcohols (methanol, ethanol, and butanol) were reacted with methyl oleate to make chloro alkoxy compounds in 29.8–77.9 % yields. In an effort to make a branched saturated ether we removed the chlorine moiety of the chloro alkoxy compounds. Dehalogenation was achieved under basic conditions over a Pd/C catalyst in 2‐propanol. Reaction times increased substantially as the size of the adjacent alkoxy group increased. The reaction rate could be improved by heating the reactions above 100 °C in a pressure reactor. Increased reaction temperature also resulted in an increase in ketone side products from the competing elimination reactions. Saturated ether yields were 4.1–43.2 %.
Growth and Biomass Characteristics of Picochlorum oklahomensis and Nannochloropsis oculata
Authors: Zhu Yan , Dunford Nurhan Turgut 
Published: March 2013

AbstractBiofuels derived from microalgae are considered a viable alternative energy resource that eliminates the major drawbacks associated with biofuels produced from land crops. Strain selection is a critical factor for the success of microalgal production systems. This study evaluates Picochlorum oklahomensis (PO) as a potential microalga strain for biofuel and bioproduct applications. Nannochloropsis oculata (NO) was included in the study as a well‐studied reference strain with biomass properties suitable for commercial applications. Growth pattern including specific growth rates, generation time and maximum biomass concentrations in culture media were determined for both PO and NO. Oil and protein contents and fatty acid composition of both strains were analyzed. PO had a higher biomass concentration in the medium and shorter generation time than NO. Both strains were rich in oil, protein and polyunsaturated fatty acids. This study indicates that PO can be a viable strain for bioproduct manufacturing because of its high oil and protein content and biomass productivity.
Variable density and viscosity, miscible displacements in horizontal Hele-Shaw cells. Part 2. Nonlinear simulations
Authors: John M. O. , Oliveira R. M. , Heussler F. H. C. , Meiburg E. 
Published: March 2013

AbstractDirect numerical simulations of the variable density and viscosity Navier–Stokes equations are employed, in order to explore three-dimensional effects within miscible displacements in horizontal Hele-Shaw cells. These simulations identify a number of mechanisms concerning the interaction of viscous fingering with a spanwise Rayleigh–Taylor instability. The dominant wavelength of the Rayleigh–Taylor instability along the upper, gravitationally unstable side of the interface generally is shorter than that of the fingering instability. This results in the formation of plumes of the more viscous resident fluid not only in between neighbouring viscous fingers, but also along the centre of fingers, thereby destroying their shoulders and splitting them longitudinally. The streamwise vorticity dipoles forming as a result of the spanwise Rayleigh–Taylor instability place viscous resident fluid in between regions of less viscous, injected fluid, thereby resulting in the formation of gapwise vorticity via the traditional, gap-averaged viscous fingering mechanism. This leads to a strong spatial correlation of both vorticity components. For stronger density contrasts, the streamwise vorticity component increases, while the gapwise component is reduced, thus indicating a transition from viscously dominated to gravitationally dominated displacements. Gap-averaged, time-dependent concentration profiles show that variable density displacement fronts propagate more slowly than their constant density counterparts. This indicates that the gravitational mixing results in a more complete expulsion of the resident fluid from the Hele-Shaw cell. This observation may be of interest in the context of enhanced oil recovery or carbon sequestration applications.
Effect of turbulent fluctuations on the drag and lift forces on a towed sphere and its boundary layer
Authors: Homann Holger , Bec Jérémie , Grauer Rainer 
Published: March 2013

AbstractThe impact of turbulent fluctuations on the forces exerted by a fluid on a towed spherical particle is investigated by means of high-resolution direct numerical simulations. The measurements are carried out using a novel scheme to integrate the two-way coupling between the particle and the incompressible surrounding fluid flow maintained in a high-Reynolds-number turbulent regime. The main idea consists of combining a Fourier pseudo-spectral method for the fluid with an immersed-boundary technique to impose the no-slip boundary condition on the surface of the particle. This scheme is shown to converge as the power $3/ 2$ of the spatial resolution. This behaviour is explained by the ${L}_{2} $ convergence of the Fourier representation of a velocity field displaying discontinuities of its derivative. Benchmarking of the code is performed by measuring the drag and lift coefficients and the torque-free rotation rate of a spherical particle in various configurations of an upstream-laminar carrier flow. Such studies show a good agreement with experimental and numerical measurements from other groups. A study of the turbulent wake downstream of the sphere is also reported. The mean velocity deficit is shown to behave as the inverse of the distance from the particle, as predicted from classical similarity analysis. This law is reinterpreted in terms of the principle of ‘permanence of large eddies’ that relates infrared asymptotic self-similarity to the law of decay of energy in homogeneous turbulence. The developed method is then used to attack the problem of an upstream flow that is in a developed turbulent regime. It is shown that the average drag force increases as a function of the turbulent intensity and the particle Reynolds number. This increase is significantly larger than predicted by standard drag correlations based on laminar upstream flows. It is found that the relevant parameter is the ratio of the viscous boundary layer thickness to the dissipation scale of the ambient turbulent flow. The drag enhancement can be motivated by the modification of the mean velocity and pressure profile around the sphere by small-scale turbulent fluctuations. It is demonstrated that the variance of the drag force fluctuations can be modelled by means of standard drag correlations. Temporal correlations of the drag and lift forces are also presented.
Organizational Leadership: Motives and Behaviors of Leaders in Current Organizations
Authors: Martí Margarita , Gil Francisco , Barrasa Angel 
Published: March 2013

Organizational leadership is fundamental for the working and development of current organizations. It helps members of an organization to face transcendental challenges. One of the fundamental aspects of leaders is their personal characteristics and behaviour as perceived by their co-workers. Although research has established a relationship between these components, findings have failed to come up with any congruent evidence and further to this the organizations and contexts used are from several decades ago.This article, which forms part of the international GLOBE project, analyses the relationship between motives and behaviour as perceived by co-workers in organizations, using quantitative and qualitative methods and including technological innovations. Using samples from 40 corporate directors and 84 of their co-workers, from different companies, it confirms how the main motives of leaders (power, affiliation and achievement) are related to different behavioral patterns (power to authoritarian, non-dependent and non-social-skill behaviours; affiliation to relationship and dependent behaviors, and achievement to proactive behaviors). It discusses the results with relation to traditional research and suggests practical measures and proposals for future investigations in this area.
Content Validity and Metric Properties of a Pool of Items Developed to Assess Humor Appreciation
Authors: Carretero-Dios Hugo , Pérez Cristino , Buela-Casal Gualberto 
Published: March 2013

This research deals with assessing humor appreciation and highlights some of the strategies that can be used in two necessary stages in the construction of a test: the content validity study and the item analysis. First, we analyzed the content validity of a battery of 200 items developed to assess humor appreciation. Second, we analyzed the metric properties of the selected items by means of two studies. The first study was a pre-pilot analysis of the items in a sample of 212 participants, and the second study was a new item analysis in a sample of 344 Spanish people aged between 18 and 71 years. To determine content validity, we calculated interjudge agreement on item-facet theoretical match. Each item was assessed by seven judges, and the selection criterion used was a minimum agreement of 70%. This procedure led to eliminating 27 items.Subsequent item analyses led to a preliminary proposal for a 40-item scale (Escala de Apreciación del Humor, EAHU [Humor Appreciation Scale]) with appropriate descriptive statistics as well as discrimination and homogeneity values. The internal empirical structure of the scale matched the operative definition of humor appreciation, and the Cronbach’s alpha of the EAHU scores ranged from .72 to .89.
Assessment of the Efficacy of a Peer Mentoring Program in a University Setting
Authors: Alonso Miguel A. , Castaño Gloria , Calles Ana M. , Sánchez-Herrero Silvia 
Published: March 2013

In the present study, the efficacy of a formal mentoring program applied to fourth and fifth year students of the Psychology Faculty of the Complutense University is assessed. In this program, fifth-year students took on the role of mentors and fourth-year students, the role of mentees. To assess the efficacy, the group of mentors was compared with a group of non-mentors and the group of mentees with a group of non-mentees, before and after the program, taking into account the variables related to career development function (knowledge acquired of the academic setting and satisfaction with the career of Psychology) and the psychosocial function (self-concept, self-esteem, self-efficacy, and involvement).The results show a statistically significant increase in the knowledge acquired about the academic setting as a consequence of the program, both in the group of mentors and in the group of mentees. Moreover, the mentors achieved a better average grade in the subjects of the specialty of Work Psychology. There were no statistically significant differences between the experimental group and the control group in satisfaction with the career of Psychology, or in self-concept, self-esteem, or self-efficacy.
Comparison of Channeling Contrast between Ion and Electron Images
Authors: Giannuzzi L.A. , Michael J.R. 
Published: March 2013

AbstractIon channeling contrast (iCC) and electron channeling contrast (eCC) are caused by variation in signal resulting from changes in the angle of the incident beam and the crystal lattice with respect to the target. iCC is directly influenced by the incident ion range in crystalline materials. The ion range is larger for low-index crystal orientated grains, resulting in the emission of fewer secondary electrons at the surface yielding a lower signal. Ions are stopped closer to the surface for off-axis grains, resulting in the emission of many secondary electrons yielding a higher signal. Conversely, backscattered electrons (BSEs) are the primary contribution to eCC. BSEs are diffracted or channeled to form an electron channeling pattern (ECP). The BSE emission of the ECP peaks when the electron beam is normal to the surface of an on-axis grain, and therefore a bright signal is observed. Thus, iCC and eCC images yield inverse contrast behavior for on-axis oriented grains. Since there is a critical angle associated with particle channeling, accurately determining grain boundary locations require the acquisition of multiple images obtained at different tilt conditions.
Prediction of function for the polyprenyl transferase subgroup in the isoprenoid synthase superfamily
Authors: Wallrapp Frank H. , Pan Jian-Jung , Ramamoorthy Gurusankar , Almonacid Daniel E. , Hillerich Brandan S. , Seidel Ronald , Patskovsky Yury , Babbitt Patricia C. , Almo Steven C. , Jacobson Matthew P. , Poulter C. Dale 
Published: March 2013

Significance
This paper reports a large-scale collaborative study of an approach for predicting the function of chain elongation prenyltransferases from genetic data. A diverse set of genes for enzymes in the isoprenoid synthase superfamily was identified for cloning, expression, X-ray structural analysis, and prediction of function by docking to homology models. Blind predictions, later verified biochemically, were accurate to within one isoprene unit for all but a few of the 74 enzymes studied, an extraordinarily high level of prediction given that the enzymes often give products whose chain lengths vary by one isoprene unit.
Peakr: simulating solid-state NMR spectra of proteins
Authors: Schneider Robert , Odronitz Florian , Hammesfahr Björn , Hellkamp Marcel , Kollmar Martin 
Published: March 2013

Abstract
Motivation: When analyzing solid-state nuclear magnetic resonance (NMR) spectra of proteins, assignment of resonances to nuclei and derivation of restraints for 3D structure calculations are challenging and time-consuming processes. Simulated spectra that have been calculated based on, for example, chemical shift predictions and structural models can be of considerable help. Existing solutions are typically limited in the type of experiment they can consider and difficult to adapt to different settings.
Results: Here, we present Peakr, a software to simulate solid-state NMR spectra of proteins. It can generate simulated spectra based on numerous common types of internuclear correlations relevant for assignment and structure elucidation, can compare simulated and experimental spectra and produces lists and visualizations useful for analyzing measured spectra. Compared with other solutions, it is fast, versatile and user friendly.
Availability and implementation: Peakr is maintained under the GPL license and can be accessed at http://www.peakr.org. The source code can be obtained on request from the authors.
Contact: robert.schneider@ibs.fr or mako@nmr.mpibpc.mpg.de
Supplementary information: Supplementary data are available at Bioinformatics online.
Identifying Lyman α emitters powered by AGNs
Authors: Baek Sunghye , Ferrara Andrea 
Published: March 2013

Abstract
Lyman α emitters (LAEs) are usually thought to be powered by star formation. It has been recently reported that a fraction of LAEs at redshift z ∼ 3–4 host an active galactic nuclei (AGNs). If an AGN is present, it could be obscured and undetectable in X-rays, but yet dominate the Lyα luminosity. We examine the properties of these AGN-powered LAEs at high redshift (z ≥ 6) using radiative transfer cosmological simulations and obtain a reliable criterion to identify them from their observed Lyα line and surface brightness. We find that these sources should have (a) negative line weighted skewness, Sw &lt; 0, and (b) surface brightness profile full width at half-maximum ≥1.5 arcsec. This parameter space cannot be populated by starburst LAEs. Thus, LAEs satisfying this criterion would be strong candidates for the presence of a hidden AGN powering their luminosity.