bluuebunny/crossref_metadata_2025_split huggingface dataset:
A phase‐field model for cohesive fracture
Authors: Verhoosel Clemens V. , de Borst René 
Published: July 2013

SUMMARYIn this paper, a phase‐field model for cohesive fracture is developed. After casting the cohesive zone approach in an energetic framework, which is suitable for incorporation in phase‐field approaches, the phase‐field approach to brittle fracture is recapitulated. The approximation to the Dirac function is discussed with particular emphasis on the Dirichlet boundary conditions that arise in the phase‐field approximation. The accuracy of the discretisation of the phase field, including the sensitivity to the parameter that balances the field and the boundary contributions, is assessed at the hand of a simple example. The relation to gradient‐enhanced damage models is highlighted, and some comments on the similarities and the differences between phase‐field approaches to fracture and gradient‐damage models are made. A phase‐field representation for cohesive fracture is elaborated, starting from the aforementioned energetic framework. The strong as well as the weak formats are presented, the latter being the starting point for the ensuing finite element discretisation, which involves three fields: the displacement field, an auxiliary field that represents the jump in the displacement across the crack, and the phase field. Compared to phase‐field approaches for brittle fracture, the modelling of the jump of the displacement across the crack is a complication, and the current work provides evidence that an additional constraint has to be provided in the sense that the auxiliary field must be constant in the direction orthogonal to the crack. The sensitivity of the results with respect to the numerical parameter needed to enforce this constraint is investigated, as well as how the results depend on the orders of the discretisation of the three fields. Finally, examples are given that demonstrate grid insensitivity for adhesive and for cohesive failure, the latter example being somewhat limited because only straight crack propagation is considered. Copyright © 2013 John Wiley & Sons, Ltd.
Leadership Style in Relation to Organizational Change and Organizational Creativity: Perceptions from Nonprofit Organizational Members
Authors: Lutz Allen Stephanie , Smith Joseph E. , Da Silva Nancy 
Published: July 2013

AbstractAs the environment within which organizations act continues to change and becomes increasingly competitive, maintaining an organizational climate that supports change and encourages creativity is a key objective for organizational leaders. This article examines the relationship between leadership style (transformational, transactional, laissez‐faire) and members' perceptions of the psychological climate for organizational change readiness and psychological climate for organizational creativity. Results indicate that transformational leaders have a direct positive relationship with psychological climate for organizational change readiness and organizational creativity, while laissez‐faire leaders have a negative relationship.
Maternal coping, appraisals and adjustment following diagnosis of fetal anomaly
Authors: Horsch Antje , Brooks Chloe , Fletcher Helen 
Published: July 2013

ABSTRACTObjectiveSo far, associations between appraisals, maternal adjustment and coping following diagnosis of fetal anomaly have not been investigated in women who continue with their pregnancy.MethodThis study measured maternal coping and adjustment after and appraisal of a diagnosis of fetal anomaly in 40 mothers who had continued with their pregnancy using a cross‐sectional questionnaire design.ResultsBased on retrospective reporting, 35% of participants met full diagnostic criteria for post‐traumatic stress disorder after having received the diagnosis. Women were significantly more depressed (p < 0.001) and anxious (p < 0.001) and reported significantly less positive affect (p < 0.05) after having received the diagnosis in comparison to the time after childbirth. There were no significant differences between emotion‐focused and problem‐focused coping. Stressful life events, women's age, number of people providing support and problem‐focused coping explained 57.6% of variance in anxiety and depression after childbirth. Satisfaction with social support, emotion‐focused coping and problem‐focused coping significantly explained 40.6% of variance in positive affect after childbirth.ConclusionFollowing a prenatal diagnosis and for the remainder of their pregnancy, particular attention should be paid to older mothers, those experiencing additional stressful life events and those who are socially isolated, as these women may experience greater distress after childbirth. © 2013 John Wiley & Sons, Ltd.
Parental coping and posttraumatic stress symptoms among pediatric cancer populations: tests of competing models
Authors: Stoppelbein Laura , Greening Leilani , Wells Hayley 
Published: July 2013

AbstractObjectiveThe objective of this study is to examine the relation between parental coping style and the risk of parental and child posttraumatic stress symptoms (PTSS) among pediatric cancer survivors.MethodsChild survivors of cancer ranging from 6 to 16 years of age (N = 111) completed standardized measures of depression and PTSS, while their parents completed standardized measures of PTSS and coping styles.ResultsCorrelational analyses revealed that active and passive coping strategies were positively related to parental PTSS. Although child and parental PTSS were significantly related to each other, only one parental coping strategy—using substances—was significantly related to child PTSS. Regression analyses revealed support for a mediation and not for a moderation model for this relation, thereby suggesting that the relation between parental and child PTSS is mediated by parental substance use.ConclusionsClinical implications including identifying risk factors for PTSS among pediatric cancer survivors are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
Crystal structure of Saccharomyces cerevisiae Aro8, a putative α‐aminoadipate aminotransferase
Authors: Bulfer Stacie L. , Brunzelle Joseph S. , Trievel Raymond C. 
Published: July 2013

Abstractα‐Aminoadipate aminotransferase (AAA‐AT) catalyzes the amination of 2‐oxoadipate to α‐aminoadipate in the fourth step of the α‐aminoadipate pathway of lysine biosynthesis in fungi. The aromatic aminotransferase Aro8 has recently been identified as an AAA‐AT in Saccharomyces cerevisiae. This enzyme displays broad substrate selectivity, utilizing several amino acids and 2‐oxo acids as substrates. Here we report the 1.91Å resolution crystal structure of Aro8 and compare it to AAA‐AT LysN from Thermus thermophilus and human kynurenine aminotransferase II. Inspection of the active site of Aro8 reveals asymmetric cofactor binding with lysine‐pyridoxal‐5‐phosphate bound within the active site of one subunit in the Aro8 homodimer and pyridoxamine phosphate and a HEPES molecule bound to the other subunit. The HEPES buffer molecule binds within the substrate‐binding site of Aro8, yielding insights into the mechanism by which it recognizes multiple substrates and how this recognition differs from other AAA‐AT/kynurenine aminotransferases.
On the single‐particle‐reduced entropy of a gated nanowire system in the Coulomb blockade regime
Authors: Castelo José María , Indlekofer Klaus Michael , Malindretos Joerg 
Published: July 2013

Abstractmagnified imageIn this Letter, the single‐particle‐reduced entropy of a nanowire field‐effect transistor (NWFET) in the Coulomb blockade regime is studied by means of a multi‐configura‐tional self‐consistent Green's function approach. Assuming that the many‐body statistical preparation of the system is described by a mixture of Slater determinants of relevant natural orbitals, the single‐particle‐reduced entropy can be interpreted as a measure of the degree of mixture of the system's preparation. Considering the realistic case of an InP based NWFET, we present current–voltage characteristics and entropy diagrams for a range of equilibrium and non‐equilibrium states. Signatures of few‐electron Coulomb charging effects can be identified, as known from experimental situations. Furthermore, we illustrate the significance of the single‐particle‐reduced entropy by analyzing the corresponding electronic configurations. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Group III nitride core–shell nano‐ and microrods for optoelectronic applications
Authors: Mandl Martin , Wang Xue , Schimpke Tilman , Kölper Christopher , Binder Michael , Ledig Johannes , Waag Andreas , Kong Xiang , Trampert Achim , Bertram Frank , Christen Jürgen , Barbagini Francesca , Calleja Enrique , Strassburg Martin 
Published: July 2013

Abstractmagnified imageIn the past few years, tremendous progress has been demonstrated on epitaxial growth and processing of group III nitride nano‐ and microrods (NAMs). This has also enabled the fabrication of optoelectronic devices based on NAMs as active elements. However, their efficiency is still far behind the performance of conventional GaN‐based light emitting diodes (LEDs). This Review presents the most recent activities on the growth and processing of NAMs exhibiting a core–shell geometry, i.e. structures which consist of an active region shell layer wrapped around a three‐dimensional (3D) core, which allow for an enormous increase in active area compared to planar technology. The most common growth approaches using metalorganic vapour phase epitaxy are described and evaluated with particular regard to their potential for solid state lighting applications. Examples for the unique properties of 3D NAMs are presented including their excellent crystalline quality. Furthermore, factors limiting the overall performance of 3D core–shell LEDs are revealed and the potential of overcoming these limitations are discussed. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Drop Test of Plastic Packagings – Correlation with Material Parameters and Change of Packaging Behaviour After Impact of Standard Liquids
Authors: Menrad Andreas , Goedecke Thomas , Wagner Manfred H. 
Published: July 2013

A guided drop test was performed to achieve a defined and reproducible impact orientation of jerrycans. The drop heights where 50% of the jerrycans experienced a failure from a crack where fluid can escape (50% failure drop height) were compared among jerrycans made of four different materials, in their original state and preconditioned with standard liquids. To analyse the impact of only elevated temperatures, the packages were preconditioned for 21 days at 40°C without the use of chemicals.The 50% failure drop height was compared by using Young's modulus; the notched impact strength (NIS) of specimen cut from plates which were manufactured by compression moulding and the notched tensile impact strength of specimen cut‐outs of the jerrycans' side walls. The NIS depends highly on the thermal preconditioning of the plates being manufactured by compression moulding. A trend can be seen that a higher Young's modulus, a higher NIS and a higher notched tensile impact strength result in a higher 50% failure drop height, but the values are spread. The influence of the wall thickness cannot be neglected.The change of the 50% failure drop height in regard to the preconditioning at 40°C with and without nitric acid was compared in terms of their resistance to molecular degradation, density and degree of crystallinity. The conditioning at elevated temperature causes post‐crystallization. It was shown that the resistance to molecular degradation determined on pressed plates correlates with the change of the 50% failure drop height after pre‐storage with nitric acid. Copyright © 2013 John Wiley & Sons, Ltd.
Map Building Fusing Acoustic and Visual Information using Autonomous Underwater Vehicles
Authors: Kunz Clayton , Singh Hanumant 
Published: July 2013

AbstractWe present a system for automatically building three‐dimensional (3‐D) maps of underwater terrain fusing visual data from a single camera with range data from multibeam sonar. The six‐degree‐of‐freedom location of the camera relative to the navigation frame is derived as part of the mapping process, as are the attitude offsets of the multibeam head and the onboard velocity sensor. The system uses pose graph optimization and the square root information smoothing and mapping framework to simultaneously solve for the robot's trajectory, the map, and the camera location in the robot's frame. Matched visual features are treated within the pose graph as images of 3‐D landmarks, while multibeam bathymetry submap matches are used to impose relative pose constraints linking robot poses from distinct tracklines of the dive trajectory. The navigation and mapping system presented works under a variety of deployment scenarios on robots with diverse sensor suites. The results of using the system to map the structure and the appearance of a section of coral reef are presented using data acquired by the Seabed autonomous underwater vehicle.
Biochips for Cell Biology by Combined Dip‐Pen Nanolithography and DNA‐Directed Protein Immobilization
Authors: Arrabito Giuseppe , Reisewitz Stephanie , Dehmelt Leif , Bastiaens Philippe I. , Pignataro Bruno , Schroeder Hendrik , Niemeyer Christof M. 
Published: July 2013

AbstractA general methodology for patterning of multiple protein ligands with lateral dimensions below those of single cells is described. It employs dip pen nanolithography (DPN) patterning of DNA oligonucleotides which are then used as capture strands for DNA‐directed immobilization (DDI) of oligonucleotide‐tagged proteins. This study reports the development and optimization of PEG‐based liquid ink, used as carrier for the immobilization of alkylamino‐labeled DNA oligomers on chemically activated glass surfaces. The resulting DNA arrays have typical spot sizes of 4–5 μm with a pitch of 12 μm micrometer. It is demonstrated that the arrays can be further functionalized with covalent DNA‐streptavidin (DNA‐STV) conjugates bearing ligands recognized by cells. To this end, biotinylated epidermal growth factor (EGF) is coupled to the DNA‐STV conjugates, the resulting constructs are hybridized with the DNA arrays and the resulting surfaces used for the culturing of MCF‐7 (human breast adenocarcinoma) cells. Owing to the lateral diffusion of transmembrane proteins in the cell's plasma membrane, specific recruitment and concentration of EGF receptor can be induced specifically at the sites where the ligands are bound on the solid substrate. This is a clear demonstration that this method is suitable for precise functional manipulations of subcellular areas within living cells.
Adopting agile practices when developing software for use in the medical domain
Authors: McHugh Martin , McCaffery Fergal , Casey Valentine 
Published: July 2013

SUMMARYNon‐safety critical software developers have been reaping the benefits of adopting agile practices for a number of years. However, developers of safety critical software often have concerns about adopting agile practices. Through performing a literature review, this research has identified the perceived barriers to following agile practices when developing medical device software. A questionnaire‐based survey was also conducted with medical device software developers in Ireland to determine the barriers to adopting agile practices. The survey revealed that half of the respondents develop software in accordance with a plan‐driven software development lifecycle and that they believe that there are a number of perceived barriers to adopting agile practices when developing regulatory compliant software such as being contradictory to regulatory requirements, insufficient coverage of risk management activities and the lack of up‐front planning. In addition, a comparison is performed between the perceived and actual barriers. Based upon the findings of the literature review and survey, it emerged that no external barriers exist to adopting agile practices when developing medical device software and the barriers that do exists are internal barriers such as getting stakeholder buy in. Copyright © 2013 John Wiley & Sons, Ltd.
Semi‐supervised clustering methods
Authors: Bair Eric 
Published: July 2013

Cluster analysis methods seek to partition a data set into homogeneous subgroups. It is useful in a wide variety of applications, including document processing and modern genetics. Conventional clustering methods are unsupervised, meaning that there is no outcome variable nor is anything known about the relationship between the observations in the data set. In many situations, however, information about the clusters is available in addition to the values of the features. For example, the cluster labels of some observations may be known, or certain observations may be known to belong to the same cluster. In other cases, one may wish to identify clusters that are associated with a particular outcome variable. This review describes several clustering algorithms (known as ‘semi‐supervised clustering’ methods) that can be applied in these situations. The majority of these methods are modifications of the populark‐means clustering method, and several of them will be described in detail. A brief description of some other semi‐supervised clustering algorithms is also provided.This article is categorized under:Statistical Learning and Exploratory Methods of the Data Sciences > Clustering and Classification
Techniques for monitoring carnivore behavior using automatic thermal video
Authors: Brawata Renee L. , Raupach Timothy H. , Neeman Teresa 
Published: July 2013

ABSTRACTThe detectability of nocturnal carnivores is very low, because such data on many species can be difficult to acquire. Here, we design an automatic thermal video recording system for studying cryptic mammalian predators at food and water resources in Australia. We trialed different sampling procedures in contrasting environments between August 2005 and February 2006 to identify aspects of survey design that influenced video interpretability. We then compared the accuracy of the remote recording system to that of direct human observation. We found our system to be most effective when temperature settings were correctly adjusted and procedures were adapted for the sampling environment. We identified that the presence of vegetation and the distance between the target species and camera were the most important factors in video interpretability. The remote recording system was found to be as effective at recording both visits and behavior as direct human observation at a focal point. We propose that the automatic thermal video capture system has the potential to be an extremely useful tool for monitoring otherwise difficult to observe species. © 2013 The Wildlife Society.
Prognostic Nutritional Index Predicts Postoperative Outcome in Colorectal Cancer
Authors: Mohri Yasuhiko , Inoue Yasuhiro , Tanaka Koji , Hiro Junichirou , Uchida Keiichi , Kusunoki Masato 
Published: July 2013

AbstractBackgroundThe prognostic nutritional index (PNI), which is calculated based on the serum albumin concentration and peripheral blood lymphocyte count, is a useful tool for predicting short‐term and long‐term postoperative outcome in patients undergoing cancer surgery. However, few studies have investigated PNI in colorectal cancer surgery. We examined the ability of PNI to predict short‐ and long‐term outcomes in patients with colorectal cancer.MethodsThis retrospective study included 365 patients who underwent resection for colorectal cancer. The prognostic nutritional status was calculated on the basis of admission data as follows: 10 × serum albumin (g/dl) + 0.005 × total lymphocyte count (per mm3). The primary outcomes measured were the impact of PNI on overall survival and postoperative complications.ResultsKaplan–Meier analysis and the log rank test revealed that low PNI was significantly associated with poor survival (P < 0.0001). In multivariate analysis for survival, preoperative low PNI was an independent prognostic factor for poor survival: odds ratio: 2.25, 95 % confidence interval 1.42–3.59). Moreover, low PNI significantly correlated with the incidence of postoperative complications, especially serious ones.ConclusionsPreoperative PNI is a useful predictor of postoperative complications and survival in patients with colorectal cancer.
Ethnic identity development and ethnic discrimination: Examining longitudinal associations with adjustment for Mexican‐origin adolescent mothers
Authors: Toomey Russell B. , Umaña‐Taylor Adriana J. , Updegraff Kimberly A. , Jahromi Laudan B. 
Published: July 2013

ABSTRACTFew studies examine normative developmental processes among teenage mothers. Framed from a risk and resilience perspective, this prospective study examined the potential for ethnic identity status (e.g., diffuse, achieved), a normative developmental task during adolescence, to buffer the detrimental effects of discrimination on later adjustment and self‐esteem in a sample of 204 Mexican‐origin adolescent mothers. Ethnic discrimination was associated with increases in depressive symptoms and decreases in self‐esteem over time, regardless of ethnic identity status. However, ethnic discrimination was only associated with increases in engagement in risky behavior among diffuse adolescents, suggesting that achieved or foreclosed identities buffered the risk of ethnic discrimination on later risky behavior. Findings suggest that ethnic identity resolution (i.e., the component shared by those in foreclosed and achieved statuses) may be a key cultural factor to include in prevention and intervention efforts aimed to reduce the negative effects of ethnic discrimination on later externalizing problems.
Turbulence during the reflection of internal gravity waves at critical and near-critical slopes
Authors: Chalamalla Vamsi K. , Gayen Bishakhdatta , Scotti Alberto , Sarkar Sutanu 
Published: July 2013

AbstractDirect numerical simulation is performed with a focus on the characterization of nonlinear dynamics during reflection of a plane internal wave at a sloping bottom. The effect of incoming wave amplitude is assessed by varying the incoming Froude number, $Fr$, and the effect of off-criticality is assessed by varying the slope angle in a range of near-critical values. At low $\mathit{Fr}$, the numerical results agree well with linear inviscid theory of near-critical internal wave reflection. With increasing $\mathit{Fr}$, the reflection process becomes nonlinear with the formation of higher harmonics and the initiation of fine-scale turbulence during the evolution of the reflected wave. Later in time, the wave response becomes quasi-steady with a systematic dependence of turbulence on the temporal and spatial phase. Convective instabilities are found to play a crucial role in the formation of turbulence during each cycle. The cycle evolution of flow statistics is studied in detail and qualitative differences between off-critical and critical reflection are identified. The parametric dependence of turbulence levels on Froude number and slope angle is calculated. Interestingly, at a given value of $\mathit{Fr}$, the turbulent kinetic energy (TKE) can be higher for somewhat off-critical reflection compared to exactly critical reflection. For a fixed slope angle, as the Froude number increases in the simulated cases, the fraction of the input wave energy converted into the turbulent kinetic energy and the fraction of the input wave power dissipated by turbulence also increase.