bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship Between the FFM Personality Traits, State Psychopathology, and Sexual Compulsivity in a Sample of Male College Students
Authors: Pinto Joana , Carvalho Joana , Nobre Pedro J.
Published: July 2013

Introduction

Several studies have advocated a relationship between psychopathological features and sexual compulsivity. Such relationship is often found among individuals seeking help for out of control sexual behavior, suggesting that the association between psychological adjustment and sexual compulsivity may have a significant clinical value. However, a more complete approach to the topic of sexual compulsivity would also include the analysis of nonclinical samples as healthy individuals may be at risk of developing some features of hypersexuality in the future.

Aim

The aim of this study was to explore the relationship between stable traits of personality, state psychopathology, and sexual compulsivity in a sample of male college students. Furthermore, the potential mediating role of state psychopathology in the relationship between personality traits and sexual compulsivity was tested.

Main Outcome Measures

Participants completed the following measures: the NEO Five-Factor Inventory, the Brief Symptom Inventory, and the Compulsive Sexual Behavior Inventory-22.

Methods

The sample included 152 male college students recruited in a Portuguese university using nonrandom methods. The measures were completed individually and anonymously.

Results

Findings on state psychopathology suggested that psychoticism may be one of the key dimensions associated with sexual compulsivity in male students. The personality traits of Neuroticism and Agreeableness were also significant predictors of sexual compulsivity. Findings on the mediating effects suggested that state psychopathology mediated the relationship between Neuroticism and sexual compulsivity but not between Agreeableness and sexual compulsivity.

Conclusions

A psychopathological path (encompassing Neuroticism and state psychopathology) and a behavioral path (encompassing Agreeableness features) may be involved in sexual compulsivity as reported by a nonclinical sample of male students.
Directors' duties: improper purposes or implied terms?
Authors: Lim Ernest
Published: July 2013

This paper challenges the prevailing assumption that the directors' duty to act for proper purposes under s 171 (b) of the Companies Act 2006 is well-grounded on authorities such as Howard Smith Ltd v Ampol Petroleum Ltd, Hogg v Cramphorn Ltd, Lee Panavision Ltd v Lee Lighting Ltd and Extrasure Travel Insurances Ltd v Scattergood. It advances the argument that a close analysis of these authorities shows that, despite the use of the language of proper purpose, the primary and central justification for impugning the director's exercise of powers in question is that an implied term of the company's constitution was contravened. Given that case-law support for the proper purpose duty is at best overstated and at worst misconceived, a consideration of whether future cases concerning whether directors have breached their duties should be decided on the basis of whether an implied term of the constitution has been contravened under s 171(a), instead of whether directors have exercised their powers for proper purposes under s 171(b), is warranted. It is submitted that deciding cases based on implied terms under s 171(a) is more defensible because: (i) high authorities such as Attorney General of Belize v Belize Telecom and Equitable Life Assurance Society v Hyman endorse the use of implied terms as a technique for controlling the exercise of discretionary powers conferred on directors; (ii) a principled approach for implying terms can be derived from these authorities; (iii) there are safeguards that are built into the doctrine of implied terms; (iv) the application of the improper purpose doctrine gives rise to perennial problems; and (v) that doctrine is based on a fallacious conceptual justification.
Sympatric sister species in rodents are more chromosomally differentiated than allopatric ones: implications for the role of chromosomal rearrangements in speciation
Authors: Castiglia Riccardo
Published: July 2013

A meta‐analysis approach was used to test for chromosomal speciation in rodents. Forty‐one pairs of sister species, identified in the two most species‐rich rodent families (Cricetidae andMuridae), were used as phylogenetically independent data points, each resulting from a speciation event. About 30% of sister species have an identical karyotype. There was a significant difference in the number of chromosomal differences between sympatric and allopatric sister species, compatible with a direct role of chromosomal rearrangements in speciation.
Prevention, detection and management of early chronic kidney disease: A systematic review of clinical practice guidelines
Authors: Lopez‐Vargas Pamela A , Tong Allison , Sureshkumar Premala , Johnson David W , Craig Jonathan C
Published: July 2013

Aim

In response to the increase in Chronic Kidney Disease (CKD) worldwide, several professional organizations have developed clinical practice guidelines to manage and prevent its progression. This study aims to compare the scope, content and consistency of published guidelines on CKD stages I–III.

Methods

Electronic databases of the medical literature, guideline organizations, and the websites of nephrology societies were searched to November 2011. The Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument and textual synthesis was used to appraise and compare recommendations.

Results

One consensus statement and 15 guidelines were identified and included. Methodological rigour across guidelines was variable, with average domain scores ranging from 24% to 95%. For detection of CKD, all guidelines recommended estimated glomerular filtration rate measurement, some also recommended serum creatinine and dipstick urinalysis. The recommended protein and albumin creatinine ratios and proteinuria definition thresholds varied (>150–300 mg/day to >500 mg/day). Blood pressure targets ranged (<125/75 to <140/90 mmHg). Angiotensin converting enzyme inhibitor and angiotensin receptor blockers were recommended for hypertension, as combined or as monotherapy. Protein intake recommendations varied (no restriction or 0.75 g/kg per day−1.0 g/kg per day). Salt intake of 6 g/day was recommended by most. Psychosocial support and education were recommended by few but specific strategies were absent.

Conclusion

CKD guidelines were consistent in scope but were variable with respect to their recommendations, coverage and methodological quality. To promote effective primary and secondary prevention of CKD, regularly updated guidelines that are based on the best available evidence and augmented with healthcare context‐specific strategies for implementation are warranted.
Relationship in Japan between maternal grandmothers’ perinatal support and their self‐esteem
Authors: Iseki Atsuko , Ohashi Kazutomo
Published: July 2013

This study investigated the influence on their mental well‐being of the perinatal support given by Japanese grandmothers.

The Rosenberg self‐esteem and the Center for Epidemiologic Studies Depression (CES‐D) scales were used to assess grandmothers’ mental well‐being before and after their daughters’ childbirth. Of 198 grandmothers, 176 (88.9%) supported their daughters and three patterns of perinatal support were observed: grandmothers’ support at the grandparents’ house before childbirth (n = 95) (Satogaeri bunben; Japanese traditional perinatal support), grandmothers’ support at the grandparents’ house after childbirth (n = 53); and grandmothers’ support at the daughters’ house (n = 28).

Those who supported their daughters at the grandparents’ house before childbirth – especially the middle‐aged (less than 60 years old) – showed significantly lower scores of self‐esteem. Scores of CES‐D did not significantly change before and after childbirth in either subgroup of grandmothers. It was concluded that grandmothers play an important role in supporting their daughters, and Satogaeri bunben is a typical event in modern Japan. However, Satogaeri bunben is a burden for middle‐aged grandmothers, and we need to support them.
Defense‐related transcription factors WRKY70 and WRKY54 modulate osmotic stress tolerance by regulating stomatal aperture in Arabidopsis
Authors: Li Jing , Besseau Sebastien , Törönen Petri , Sipari Nina , Kollist Hannes , Holm Liisa , Palva E. Tapio
Published: July 2013

WRKY transcription factors (TFs) have been mainly associated with plant defense, but recent studies have suggested additional roles in the regulation of other physiological processes. Here, we explored the possible contribution of two related group III WRKY TFs, WRKY70 and WRKY54, to osmotic stress tolerance. These TFs are positive regulators of plant defense, and co‐operate as negative regulators of salicylic acid (SA) biosynthesis and senescence.

We employed single and double mutants of wrky54 and wrky70, as well as a WRKY70 overexpressor line, to explore the role of these TFs in osmotic stress (polyethylene glycol) responses. Their effect on gene expression was characterized by microarrays and verified by quantitative PCR. Stomatal phenotypes were assessed by water retention and stomatal conductance measurements.

The wrky54wrky70 double mutants exhibited clearly enhanced tolerance to osmotic stress. However, gene expression analysis showed reduced induction of osmotic stress‐responsive genes in addition to reduced accumulation of the osmoprotectant proline. By contrast, the enhanced tolerance was correlated with improved water retention and enhanced stomatal closure.

These findings demonstrate that WRKY70 and WRKY54 co‐operate as negative regulators of stomatal closure and, consequently, osmotic stress tolerance in Arabidopsis, suggesting that they have an important role, not only in plant defense, but also in abiotic stress signaling.
Genetic and antigenic analyses of Porphyromonas gingivalis FimA fimbriae
Authors: Nagano K. , Abiko Y. , Yoshida Y. , Yoshimura F.
Published: July 2013

The periodontal pathogen Porphyromonas gingivalis generally expresses two distinct fimbriae, FimA and Mfa1, which play a role in biofilm formation. The fimA gene that encodes FimA fimbrilin is polymorphic, and polymerase chain reaction analysis has identified six genotypes called types I–V and Ib. We found recently that fimbriae exhibit antigenic heterogeneity among the genotypes. In the present study, we analysed the fimA DNA sequences of 84 strains of P. gingivalis and characterized the antigenicity of FimA fimbriae. Strains analysed here comprised 10, 16, 29, 13, 10 and 6 strains of types I, Ib, II, III, IV and V, respectively. DNA sequencing revealed that type Ib does not represent a single cluster and that type II sequences are remarkably diverse. In contrast, the fimA sequences of the other types were relatively homogeneous. Antigenicity was investigated using antisera elicited by pure FimA fimbriae of types I–V. Antigenicity correlated generally with the respective genotype. Type Ib strains were recognized by type I antisera. However, some strains showed cross‐reactivity, especially, many type II strains reacted with type III antisera. The levels of fimbrial expression were highly variable, and expression was positively correlated with ability of biofilm formation on a saliva‐coated plate. Further, two strains without FimA and Mfa1 fimbriae expressed fimbrial structures, suggesting that the strains produce other types of fimbriae.
Regarding a Regress
Authors: Cath Yuri
Published: July 2013

Is there a successful regress argument against intellectualism? In this article I defend the negative answer. I begin by defending Stanley andWilliamson's (2001) critique ofthe contemplation regressagainstNoë (2005). I then identify a new argument –the employment regress– that is designed to succeed where the contemplation regress fails, and which I take to be the most basic and plausible form of a regress argument against intellectualism. However, I argue that the employment regress still fails. Drawing on the previous discussion, I criticise further regress arguments given byHetherington (2006) andNoë (2005).
Impact of annual body mass index gain on obesity development in Japanese 6‐year‐old non‐obese children
Authors: Kori Hiroka , Sei Masako , Nakahori Yutaka , Imoto Issei
Published: July 2013

Background

Effective timing of preventive intervention for adolescent obesity in non‐obese school‐aged children remains unclear. The aim of this study was to examine the impact of annual body mass index (BMI) gain on the development of adolescent obesity in 6‐year‐old non‐obese Japanese children.

Methods

Longitudinal weight and height data were collected annually from 9723 children aged 6–14 years, and individual per‐year BMI gains were calculated. The BMI ≥ the 95th percentile for each age and sex defined obesity. In 6‐year‐old non‐obese children, logistic regression analyses were applied to correlate the annual BMI gain at each age with obesity at a final survey.

Results

The 6‐year‐old non‐obese children who became obese at a final survey showed larger annual BMI gains at any age compared with their peers with respect to baseline BMI. Increases in annual BMI gain, even in early school age, raised the risk of adolescent obesity. Categorical analysis also showed that children aged 6–7 years with higher annual BMI gains than 1‐SD above the mean had a significant risk for adolescent obesity (OR: 4.39 [95%CI: 2.98–6.46] in boys and 3.83 [95%CI: 2.60–5.63] in girls, respectively).

Conclusions

A larger annual BMI gain at any school age is a risk for adolescent obesity in 6‐year‐old non‐obese children with no critical period. This suggests the need for earlier and continuous school‐based surveillance using annual BMI gain for preventive intervention of adolescent obesity development.
Phylogenetic position of Jaoa, a green algal genus endemic to China
Authors: Zhu Huan , Xia Shuang , Zhang Qi , Liu Guo‐Xiang , Hu Zheng‐Yu
Published: July 2013

Jaoa prasina, a freshwater green alga endemic to China, was collected from a stream in Hubei province, China. Unialgal cultivation, morphological observation, and phylogenetic analyses of small subunit ribosomal DNA and RuBisCO large subunit sequences were performed. When cultured on agar medium, the alga was irregularly filamentous, similar to marine species of Acrochaete. Aplanospores were observed on solid medium. A vesicular‐like thallus without rhizoids developed in liquid medium, similar to specimen development in natural habitats. Molecular phylogenetic analyses revealed that Jaoa was closely related to the marine genera Acrochaete Pringsheim and Ulvella Crouan & Crouan. The results suggested the genus Jaoa is a member of the family Ulvellaceae (Ulvophyceae), which contains mostly marine algae. The family name Jaoaceae should be abandoned. We speculate that Jaoa may have evolved from a marine Ulvellaceae ancestor.
Salmon welfare index model 2.0: an extended model for overall welfare assessment of caged Atlantic salmon, based on a review of selected welfare indicators and intended for fish health professionals
Authors: Pettersen Jostein M. , Bracke Marc B.M. , Midtlyng Paul J. , Folkedal Ole , Stien Lars H. , Steffenak Håvard , Kristiansen Tore S.
Published: July 2013

Here, we present an extended version of a semantic model for overall welfare assessment of Atlantic salmon reared in sea cages. The model, called SWIM 2.0, is designed to enable fish health professionals to make a formal and standardized assessment of fish welfare using a set of reviewed welfare indicators. SWIM 2.0 supplements SWIM 1.0, which was designed for application by fish farmers. We searched the literature for documented welfare indicators that could be used by fish health professionals. The selected indicators are eyes, cardiac condition, abdominal organs, gills, opercula, skeletal muscles, vaccine‐related pathology, aberrant fish, necropsy of the dead fish and active euthanasia. Selection criteria for the SWIM 2.0 indicators were that they should be practical and measureable on salmon farms by fish health professionals and that each indicator could be divided into levels from good to poor welfare backed up by relevant scientific literature. To estimate each indicator's relative impact on welfare, all the indicators were weighted based on their respective literature reviews and according to weighting factors defined as part of the semantic modelling framework. This was ultimately amalgamated into an overall SWIM 2.0 model that can be used to calculate welfare indexes for salmon in sea cages, taking into account the available fish health expertise. Using this model, an example calculation based on recordings and samplings done from an Atlantic salmon sea cage containing 106 000 fish yielded an overall welfare index of 0.81 of a maximum of 1.0.
Parametric Lorenz Curves and the Modality of the Income Density Function
Authors: Krause Melanie
Published: July 2013

Similar looking Lorenz curves can imply very different income density functions and potentially lead to wrong policy implications regarding inequality. This paper derives a relation between a Lorenz curve and the modality of its underlying income density: given a parametric Lorenz curve, it is the sign of its third derivative which indicates whether the density is unimodal or zeromodal (i.e., downward‐sloping). The density modality of several important Lorenz curves such as the Pareto, Weibull, Singh–Maddala parametrizations and hierarchical families of Lorenz curves are discussed. A Lorenz curve performance comparison with Monte Carlo simulations and data from the UNU–WIDER World Income Inequality Database underlines the relevance of the theoretical result: curve‐fitting based on criteria such as mean squared error or the Gini difference might lead to a Lorenz curve implying an incorrectly‐shaped density function. It is therefore important to take into account the modality when selecting a parametric Lorenz curve.
Morphological changes in skin of different phototypes under the action of topical corticosteroid therapy and tacrolimus
Authors: Shlivko I. L. , Kamensky V. A. , Donchenko E.V. , Agrba P.
Published: July 2013

Background/purpose

The present study aimed to investigate the influence of topical corticosteroid therapy and tacrolimus on morphological indices of different skin phototypes and to optimize topical therapy using the OCT technique.

Methods

Twenty healthy volunteers aging from 20 to 30 (14 men and 6 women) took part in the study: 10 persons with skin phototype I, II and 10 persons with skin phototype V, VI. Morphological state of the skin was assessed before and during application of topical steroids of different strength and calciumneurin inhibitors for 49 days. Morphological state was studied in vivo using the optical coherence tomograph.

Results

Morphological manifestations of skin atrophy with the use of clobetasol propionate appear earlier than with the use of hydrocortisone 17‐butyrate; this process was faster in representatives of groups V, VI. Epidermal thinning in the zone of tacrolimus application was not recorded in any phototype.

Conclusion

Recording of early preclinical signs of epidermis thinning in the course of OCT follow‐up may be an indication for changing the corticosteroid therapy by calciumneurin inhibitors, which will permit to individualize the therapy, to increase its efficacy, and to minimize the possibility of complications in each particular case.
Discordant CD34+ cell results in peripheral blood and hematopoietic progenitor cell–apheresis product: implications for clinical decisions and impact on patient treatment
Authors: Liwski Courtney J. , Padley Douglas J. , Gustafson Michael P. , Winters Jeffrey L. , Gastineau Dennis A. , Jacob Eapen K.
Published: July 2013

Case Report

A 50‐year‐old male with T‐cell lymphoma presented for autologous peripheral blood stem cell transplantation. After granulocyte–colony‐stimulating factor (G‐CSF) mobilization, his peripheral blood CD34+ cell count was 166 × 106/L on the day before collection, which predicted a high yield of CD34+ cells in the apheresis product. The first two collections had yields much lower than expected, triggering an investigation and changes to the apheresis collection methods since mobilization appeared adequate from the peripheral CD34+ values.

Results

Changes to the apheresis collection variables and instrumentation did not improve the yields in the next three collections. The laboratory investigation demonstrated that there was an interfering substance in the patient's plasma that was causing falsely high peripheral blood CD34+ cell values and that the low CD34+ cell yields in the collections were consistent with the actual peripheral blood CD34+ cell value. Based on this finding and after discussion with the clinical service, the patient then received plerixafor to increase the number of circulating CD34+ cells before Collections 6 and 7. The patient went on to achieve the target CD34+ cell dose and subsequently underwent a successful autologous transplant with full hematopoietic engraftment.

Conclusion

This case demonstrates the importance of timely and critical review of laboratory results in the context of the specific patient. This case exemplifies how diligent review of laboratory results and open communication among the various teams can positively affect patient outcomes.
Recombinant activated factor VII in patients with acute liver failure with UNOS Status 1A: a single tertiary academic centre experience
Authors: Pham H. P. , Hsu S. X. , Parker‐Jones S. , Samstein B. , Diuguid D. , Schwartz J.
Published: July 2013

Background and Objectives

Recombinant activated factor VII (rFVIIa) is often used in off‐label indications, including many situations in which the patients are at risk of thrombosis. In this study, we retrospectively reviewed the use of rFVIIa in patients with acute liver failure – UNOS Status 1A (ALF‐1A) to determine its efficacy and safety profile.

Materials and Methods

Using the transplantation records, all adult patients with ALF‐1A were identified from 6/2001 to 3/2009. From patients' medical charts, rFVIIa dose, blood component usage, short‐term outcomes [length of intensive care unit (ICU) and hospital stay, ability to undergo orthotopic liver transplant (OLT) and in‐hospital survival rate] and adverse events were examined.

Results

Forty‐two patients with ALF‐1A were identified. Fifteen patients received rFVIIa with doses ranging between 24·4 μg/kg and 126·8 μg/kg. Three patients received two doses of rFVIIa. The age, baseline activated partial thromboplastin time (aPTT) and platelet (PLT) count were not statistically different between the group receiving rFVIIa versus the group that did not. However, the prothrombin time (PT) was significantly higher in the rFVIIa group. Although the rFVIIa group stayed in the ICU longer and required significant more blood products during admission, there was no statistical difference between the two groups in terms of length of hospital stay, ability to undergo OLT and survival rate. There was no increase in complications, including thrombosis, after receiving rFVIIa.

Conclusion

Recombinant activated factor VII (rFVIIa) appears to be safe in patients with ALF‐1A, but to elucidate its full role, a randomized controlled trial would be ideal.
An Approximate Formula to Calculate the Restoring and Damping Forces of an Air Spring With a Small Pipe
Authors: Asami Toshihiko , Yokota Yasutaka , Ise Tomohiko , Honda Itsuro , Sakamoto Hiroya
Published: July 2013

This paper proposes a simple expression for calculating the restoring and damping forces of an air spring equipped with a small pipe. Air springs are commonly used in railway vehicles, automobiles, and various vibration isolators. The air spring discussed in this study consists of two tanks connected by a long pipe. Using a pipe instead of an orifice enables flexibility in the arrangement of the two tanks. In addition, this makes it possible to manufacture a thin air spring. A vertical translational oscillating system, which consists of a single mass supported by this type of air spring, looks like a single-degree-of-freedom (SDOF) system. However, it may have two resonance points. In this paper, we propose a vibratory model of a system supported by the air spring. With the proposed model it is possible to correctly reproduce the two resonance points of a system consisting of a single mass supported by this type of air spring. In our analysis, assuming that the vibration amplitude is small and the flow through the pipe is laminar, we derive the spring constant and damping coefficient of an air spring subjected to a simple harmonic motion. Then, we calculate the frequency response curves for the system and compare the calculated results with the experimental values. According to the experiment, there is a remarkable amplitude dependency in this type of air spring, so the frequency response curves for the system change with the magnitude of the input amplitude. It becomes clear that the calculation results are in agreement with the limit case when the input amplitude approaches zero. We use a commercially available air spring in this experiment. Our study is useful in the design of thin air spring vibration isolators for isolating small vibrations.
The Definition of Point Sources: Point Charge, Mass Point and Heat Point Source—A Generalized Sternberg Definition of Concentrated Forces
Authors: Chu Haijian , Wang Minzhong
Published: July 2013

By considering the concept of point sources, such as point charge, mass point, and heat point source, we give a unified definition of these point sources with three conditions to judge what kind of distributed source in a small region can be taken as a point source by applying Sternberg's concept on concentrated forces. Comparing it with the traditional qualitative understanding of this concept, the definition gives a new condition with a very simple form. Counter-examples demonstrate that the traditional understanding of the point source is not sufficient and the new requirement should not be omitted.
Formation of Bending-Wave Band Structures in Bicoupled Beam-Type Phononic Crystals
Authors: Guo Y. Q. , Fang D. N.
Published: July 2013

Beam-type phononic crystals as one kind of periodic material bear frequency bands for bending waves. For the first time, this paper presents formation mechanisms of the phase constant spectra in pass-bands of bending waves (coupled flexural and thickness-shear waves) in bicoupled beam-type phononic crystals based on the model of periodic binary beam with rigidly connected joints. Closed-form dispersion relation of bending waves in the bicoupled periodic binary beam is obtained by our proposed method of reverberation-ray matrix (MRRM), based on which the bending-wave band structures in the bicoupled binary beam phononic crystal are found to be generated from the dispersion curves of the equivalent bending waves in the unit cell due to the zone folding effect, the cut-off characteristic of thickness-shear wave mode, and the wave interference phenomenon. The ratios of band-coefficient products, the characteristic times of the unit cell and the characteristic times of the constituent beams are revealed as the three kinds of essential parameters deciding the formation of bending-wave band structures. The MRRM, the closed-form dispersion relation, the formation mechanisms, and the essential parameters for the bending-wave band structures in bicoupled binary beam phononic crystals are validated by numerical examples, all of which will promote the applications of beam-type phononic crystals for wave filtering/guiding and vibration isolation/control.
Design of Axially Graded Columns Under a Central Force
Authors: Santoro Roberta , Elishakoff Isaac
Published: July 2013

Structures made of functionally graded materials have attracted much interest recently. The idea is to create a material that fulfills a specified function in accordance to the identified purpose of structure's utilization. In this study, a semi-inverse problem is posed of determining the needed variation of the axial grading of an inhomogeneous column subjected to a central force, generalizing the ungraded column case. Remarkably, it turns out that for a specific combination of parameters, there could exist three different axially graded columns, that possess the same buckling load. Whereas this fact is not immediately apparent, the proposed formulation leads to the design of the axially graded column in such a manner that the buckling load is not less than a prespecified load. Purpose-oriented design demands columns have at least a prespecified buckling load. To solve the problem, a combined analytical-numerical procedure is developed in this study.
A Contact Force Model With Nonlinear Compliance and Residual Indentation1
Authors: Xiong Xiaogang , Kikuuwe Ryo , Yamamoto Motoji
Published: July 2013

The contact between two bodies is a complicated phenomenon in which the force and the relative position have nonlinear relations. Empirical results in the literature show that, in some mechanical systems such as biological tissues, the relation between the contact force and the indentation is characterized by the following three features: (i) continuity of the force at the time of collision, (ii) a Hertz-like nonlinear force-indentation curve, and (iii) nonzero indentation at the time of loss of contact force. The conventional Hunt–Crossley (HC) model does not capture the feature (iii) as the model makes the contact force and the indentation reach zero simultaneously. This paper proposes a compliant contact model based on a differential-algebraic equation that satisfies all three features. The behaviors of the model and the effect of the parameters in the model are investigated through numerical simulations.
Energy Absorption of Thin-Walled Square Tubes With a Prefolded Origami Pattern—Part I: Geometry and Numerical Simulation
Authors: Ma Jiayao , You Zhong
Published: July 2013

Thin-walled tubes subjected to axial crushing have been extensively employed as energy absorption devices in transport vehicles. Conventionally, they have a square or rectangular section, either straight or tapered. Dents are sometimes added to the surface in order to reduce the initial buckling force. This paper presents a novel thin-walled energy absorption device known as the origami crash box that is made from a thin-walled tube of square cross section whose surface is prefolded according to a developable origami pattern. The prefolded surface serves both as a type of geometric imperfection to lower the initial buckling force and as a mode inducer to trigger a collapse mode that is more efficient in terms of energy absorption. It has been found out from quasi-static numerical simulation that a new collapse mode referred to as the completed diamond mode, which features doubled traveling plastic hinge lines compared with those in conventional square tubes, can be triggered, leading to higher energy absorption and lower peak force than those of conventional ones of identical weight. A parametric study indicates that for a wide range of geometric parameters the origami crash box exhibits predictable and stable collapse behavior, with an energy absorption increase of 92.1% being achieved in the optimum case. The origami crash box can be stamped out of a thin sheet of material like conventional energy absorption devices without incurring in-plane stretching due to the developable surface of the origami pattern. The manufacturing cost is comparable to that of existing thin-walled crash boxes, but it absorbs a great deal more energy during a collision.
Generalized FVDAM Theory for Periodic Materials Undergoing Finite Deformations—Part I: Framework
Authors: Cavalcante Marcio A. A. , Pindera Marek-Jerzy
Published: July 2013

The recently constructed generalized finite-volume theory for two-dimensional linear elasticity problems on rectangular domains is further extended to make possible simulation of periodic materials with complex microstructures undergoing finite deformations. This is accomplished by embedding the generalized finite-volume theory with newly incorporated finite-deformation features into the 0th order homogenization framework, and introducing parametric mapping to enable efficient mimicking of complex microstructural details without artificial stress concentrations by stepwise approximation of curved surfaces separating adjacent phases. The higher-order displacement field representation within subvolumes of the discretized unit cell microstructure, expressed in terms of elasticity-based surface-averaged kinematic variables, substantially improves interfacial conformability and pointwise traction and nontraction stress continuity between adjacent subvolumes. These features enable application of much larger deformations in comparison with the standard finite-volume direct averaging micromechanics (FVDAM) theory developed for finite-deformation applications by minimizing interfacial interpenetrations through additional kinematic constraints. The theory is constructed in a manner which facilitates systematic specialization through reductions to lower-order versions with the 0th order corresponding to the standard FVDAM theory. Part I presents the theoretical framework. Comparison of predictions by the generalized FVDAM theory with its predecessor, analytical and finite-element results in Part II illustrates the proposed theory's superiority in applications involving very large deformations.
Energy-Conservation Error Due to Use of Green–Naghdi Objective Stress Rate in Commercial Finite-Element Codes and Its Compensation
Authors: Bažant Zdeňek P. , Vorel Jan
Published: July 2013

The objective stress rates used in most commercial finite element programs are the Jaumann rate of Kirchhoff stress, Jaumann rates of Cauchy stress, or Green–Naghdi rate. The last two were long ago shown not to be associated by work with any finite strain tensor, and the first has often been combined with tangential moduli not associated by work. The error in energy conservation was thought to be negligible, but recently, several papers presented examples of structures with high volume compressibility or a high degree of orthotropy in which the use of commercial software with the Jaumann rate of Cauchy or Kirchhoff stress leads to major errors in energy conservation, on the order of 25–100%. The present paper focuses on the Green–Naghdi rate, which is used in the explicit nonlinear algorithms of commercial software, e.g., in subroutine VUMAT of ABAQUS. This rate can also lead to major violations of energy conservation (or work conjugacy)—not only because of high compressibility or pronounced orthotropy but also because of large material rotations. This fact is first demonstrated analytically. Then an example of a notched steel cylinder made of steel and undergoing compression with the formation of a plastic shear band is simulated numerically by subroutine VUMAT in ABAQUS. It is found that the energy conservation error of the Green–Naghdi rate exceeds 5% or 30% when the specimen shortens by 26% or 38%, respectively. Revisions in commercial software are needed but, even in their absence, correct results can be obtained with the existing software. To this end, the appropriate transformation of tangential moduli, to be implemented in the user's material subroutine, is derived.
Aerodynamic Simulation of Vertical-Axis Wind Turbines
Authors: Korobenko A. , Hsu M.-C. , Akkerman I. , Bazilevs Y.
Published: July 2013

Full-scale, 3D, time-dependent aerodynamics modeling and simulation of a Darrieus-type vertical-axis wind turbine (VAWT) is presented. The simulations are performed using a moving-domain finite-element-based ALE-VMS technique augmented with a sliding-interface formulation to handle the rotor-stator interactions present. We simulate a single VAWT using a sequence of meshes with increased resolution to assess the computational requirements for this class of problems. The computational results are in good agreement with experimental data. We also perform a computation of two side-by-side counterrotating VAWTs to illustrate how the ALE-VMS technique may be used for the simulation of multiple turbines placed in arrays.
On the Prediction of R-Curves for Ferroelectroelastic Ceramics
Authors: Stark Sebastian , Neumeister Peter , Balke Herbert
Published: July 2013

In ferroelectroelastic ceramics, the process of fracture is accompanied by significant inelastic deformation due to domain switching. This leads to an apparent toughening of the material, which is known as R-curve behavior. A promising approach to predict R-curves is based on one parameter fracture criteria. The scope of this paper is the examination of the physical validity of these criteria for realistic material behavior. Besides a general discussion of the problem, fracture of the lead zirconate titanate ceramic PIC151 is examined. Thereby, restriction is made to purely mechanical material behavior. The results indicate that the usage of one parameter fracture criteria is questionable. This is due to a conflict between the length scale of the zone wherein the asymptotic crack tip singularity dominates in the field solution of the continuum model and the length scale associated with the fracture process zone. It is concluded that an incorporation of the fracture process into the used fracture mechanics model is necessary to capture transient fracture of ferroelectroelastic ceramics properly.
Influence of Variable Native Arterial Diameter and Vasculature Status on Coronary Diagnostic Parameters
Authors: Goswami Ishan , Peelukhana Srikara V. , Al-Rjoub Marwan F. , Back Lloyd H. , Banerjee Rupak K.
Published: July 2013

In current practice, diagnostic parameters, such as fractional flow reserve (FFR) and coronary flow reserve (CFR), are used to determine the severity of a coronary artery stenosis. FFR is defined as the ratio of hyperemic pressures distal (p˜rh) and proximal (p˜ah) to a stenosis. CFR is the ratio of flow at hyperemic and basal condition. Another diagnostic parameter suggested by our group is the pressure drop coefficient (CDP). CDP is defined as the ratio of the pressure drop across the stenosis to the upstream dynamic pressure. These parameters are evaluated by invasively measuring flow (CFR), pressure (FFR), or both (CDP) in a diseased artery using guidewire tipped with a sensor. Pathologic state of artery is indicated by lower CFR (<2). Similarly, FFR lower than 0.75 leads to clinical intervention. Cutoff for CDP is under investigation. Diameter and vascular condition influence both flow and pressure drop, and thus, their effect on FFR and CDP was studied. In vitro experiment coupled with pressure-flow relationships from human clinical data was used to simulate pathophysiologic conditions in two representative arterial diameters, 2.5 mm (N1) and 3 mm (N2). With a 0.014 in. (0.35 mm) guidewire inserted, diagnostic parameters were evaluated for mild (∼64% area stenosis (AS)), intermediate (∼80% AS), and severe (∼90% AS) stenosis for both N1 and N2 arteries, and between two conditions, with and without myocardial infarction (MI). Arterial diameter did not influence FFR for clinically relevant cases of mild and intermediate stenosis (difference < 5%). Stenosis severity was underestimated due to higher FFR (mild: ∼9%, intermediate: ∼ 20%, severe: ∼ 30%) for MI condition because of lower pressure drops, and this may affect clinical decision making. CDP varied with diameter (mild: ∼20%, intermediate: ∼24%, severe: by 2.5 times), and vascular condition (mild: ∼35%, intermediate: ∼14%, severe: ∼ 9%). However, nonoverlapping range of CDP allowed better delineation of stenosis severities irrespective of diameter and vascular condition.
Feature profile evolution during shallow trench isolation etching in chlorine-based plasmas. III. The effect of oxygen addition
Authors: Hsu Cheng-che , Marchack Nathan , Martin Ryan M. , Pham Calvin , Hoang John , Chang Jane P.
Published: July 2013

The effect of oxygen addition to chlorine plasma during shallow trench isolation etching is quantified in this work. Specifically, the electron density and the electron temperature in an electron cyclotron resonance reactor were characterized by a Langmuir probe and were found to remain relatively constant upon O2 addition. The silicon etching rates were found to increase with the square root of the ion energy, suggesting the etching reaction is limited by the momentum transfer from ions to the surface. A relatively small amount of oxygen addition (<10%) to the chlorine plasma simultaneously changes the reactor wall conditions and surface kinetics, since oxygen becomes actively involved in the surface reactions. The change in the chamber wall conditions and surface kinetics leads to the change in both the amount of etch products and the etched feature profile. The incorporation of oxygen on the surface results in a significant change of the etched surface morphology and its composition. This work suggests a small amount of O2 addition to Cl2 plasmas in shallow trench isolation etching changes the etching behavior primarily through modifying the kinetics on etched surfaces. A multiscale etch model consisting of translating mixed layer and Monte Carlo modules for bulk and feature scale etching, respectively, was successfully applied to this case, demonstrating good agreement with the experimental results.
Acorn germination is not enhanced near cache sites relative to random locations
Authors: Sipes A.R. , Lichti N.I. , Swihart R.K.
Published: July 2013

Acorns produced by oak (genus Quercus L.) trees are eaten by numerous wildlife species, many of which may also contribute to oak regeneration by dispersing acorns to favorable microhabitats. According to the directed dispersal hypothesis, seed dispersal agents may preferentially move seeds to locations that favor seedling establishment. As a case study of the directed dispersal hypothesis, we tested the hypothesis that vertebrate scatterhoarders preferentially cache acorns in locations where conditions favor germination. We planted acorns within 0.3 m of known cache sites (cache plots) and at paired random plots that were located at equal distances from the acorn source. We then monitored germination, seedling emergence, and growth over the first year. Acorns near actual cache sites germinated at lower rates than acorns in random sites, the opposite of what would be predicted by the directed dispersal hypothesis, but insufficient seedling survival prevented statistical analysis of survival and growth. These results do not support the directed dispersal hypothesis with regard to the microhabitat at cache plots, and do not address the effects of seed burial or the potential for longer term positive effects on survival of germinated seedlings.
DUAL-PRIMAL METHODS FOR THE CARDIAC BIDOMAIN MODEL
Authors: ZAMPINI STEFANO
Published: July 2013

The cardiac Bidomain model consists in a reaction–diffusion system of partial differential equations which is often discretized by low-order finite elements in space and implicit–explicit methods in time; the resulting linear systems are very ill-conditioned and they must be solved at each time step of a cardiac beat simulation. In this paper we will construct and analyze Balancing Domain Decomposition by Constraints and Finite Element Tearing and Interconnecting Dual-Primal methods for the Bidomain operator. Proven theoretical estimates show that the proposed methods are scalable, quasi-optimal and robust with respect to possible coefficient discontinuities of the Bidomain operator and the time step. The results of extensive parallel numerical tests in three dimensions confirm the convergence rates predicted by the theory; large numerical simulations up to 400 millions of degrees of freedom on 27K cores of BlueGene/Q are also provided.
COMPARTMENTAL MODELLING OF SOCIAL DYNAMICS WITH GENERALISED PEER INCIDENCE
Authors: BISSELL J. J. , CAIADO C. C. S. , GOLDSTEIN M. , STRAUGHAN B.
Published: July 2013

A generalised compartmental method for investigating the spread of socially determined behaviour is introduced, and cast in the specific context of societal smoking dynamics with multiple peer influence. We consider how new peer influence terms, acting in both the rate at which smokers abandon their habit, and the rate at which former smokers relapse, can affect the spread of smoking in populations of constant size. In particular, we develop a three-population model (comprising classes of potential, current, and former smokers) governed by multiple incidence transfer rates with linear frequency dependence. Both a deterministic system and its stochastic analogue are discussed: in the first we demonstrate that multiple peer influence not only modifies the number of steady-states and nature of their asymptotic stability, but also introduces a new kind of non-linear "tipping-point" dynamic; while in the second we use recently compiled smoking statistics from the Northeast of England to investigate the impact of systemic uncertainty on the potential for societal "tipping". The generality of our assumptions mean that the results presented here are likely to be relevant to other compartmental models, especially those concerned with the transmission of socially determined behaviours.
keV NEUTRINO MODEL BUILDING
Authors: MERLE ALEXANDER
Published: July 2013

We review the model building aspects for keV sterile neutrinos as Dark Matter (DM) candidates. After giving a brief discussion of some cosmological, astrophysical and experimental aspects, we first discuss the currently known neutrino data and observables. We then explain the purpose and goal of neutrino model building, and review some generic methods used. Afterwards certain aspects specific for keV neutrino model building are discussed, before reviewing the bulk of models in the literature. We try to keep the discussion on a pedagogical level, while nevertheless pointing out some finer details where necessary and useful. Ideally, this review should enable a grad student or an interested colleague from cosmology or astrophysics with some prior experience to start working on the field.
INFLUENCE OF TEMPERING ON THE MICROSTRUCTURE PERFORMANCE OF THE LASER-TREATED COATINGS ON 45 STEEL
Authors: Hu Xiaodong , Li Yajiang
Published: July 2013

Effect of the tempering on the microstructures and tribological properties of the laser alloying coatings is investigated. Laser alloying of the T - Co 50/ TiC mixed powders on a 45 steel substrate can form a hard composite coating, which increased the micro-hardness and wear resistance of the substrate greatly. Such laser alloying coating was investigated by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Experimental results indicate that the tempering is able to remove the accumulation of the residual stress in a certain extent, improving the plastic and toughness properties of such coating; moreover, tempering also improves greatly the formation mechanism, making the coating have enough ability of the intensity transfer, which is beneficial in preventing the crack propagation of the interface in such coating, leading to an improvement of the wear resistance.
A MATHEMATICAL APPROACH TO ORDER BOOK MODELING
Authors: ABERGEL FRÉDÉRIC , JEDIDI AYMEN
Published: July 2013

Motivated by the desire to bridge the gap between the microscopic description of price formation (agent-based modeling) and the stochastic differential equations approach used classically to describe price evolution at macroscopic time scales, we present a mathematical study of the order book as a multidimensional continuous-time Markov chain and derive several mathematical results in the case of independent Poissonian arrival times. In particular, we show that the cancellation structure is an important factor ensuring the existence of a stationary distribution and the exponential convergence towards it. We also prove, by means of the functional central limit theorem (FCLT), that the rescaled-centered price process converges to a Brownian motion. We illustrate the analysis with numerical simulation and comparison against market data.