bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeted employee retention: Performance‐based and job‐related differences in reported reasons for staying
Authors: Hausknecht John P. , Rodda Julianne , Howard Michael J.
Published: March 2009

What makes employees stay with a particular employer? To find out, we developed a content model of 12 retention factors in the context of previous theory and research and analyzed open‐ended responses from 24,829 employees in the leisure and hospitality industry. Our coding of their comments supported the identified framework and revealed that job satisfaction, extrinsic rewards, constituent attachments, organizational commitment, and organizational prestige were the most frequently mentioned reasons for staying. High performers and nonhourly workers were more likely to cite advancement opportunities and organizational prestige as reasons for staying, whereas low performers and hourly employees were more likely to cite extrinsic rewards. These findings highlight the importance of differentiating human resource management practices when the goal is to retain valued employees. © 2009 Wiley Periodicals, Inc.
Pluripotency: Toward a gold standard for human ES and iPS cells
Authors: Smith Kelly P. , Luong Mai X. , Stein Gary S.
Published: March 2009

With the advent of technologies for the derivation of embryonic stem cells and reprogrammed stem cells, use of the term “pluripotent” has become widespread. Despite its increased scientific and political importance, there are ambiguities with this designation and a common standard for experimental approaches that precisely define this state in human cells remains elusive. Recent studies have revealed that reprogramming may occur via many pathways which do not always lead to pluripotency. In addition, the pluripotent state itself appears to be highly dynamic, leading to significant variability in the results of molecular studies. Establishment of a stringent set of criteria for defining pluripotency will be vital for biological studies and potential clinical applications in this rapidly evolving field. In this review, we explore the various definitions of pluripotency, examine the current status of pluripotency testing in the field and provide an analysis of how these assays have been used to establish pluripotency in the scientific literature. J. Cell. Physiol. 220: 21–29, 2009. © 2009 Wiley‐Liss, Inc.
Der p2 activates airway smooth muscle cells in a TLR2/MyD88‐dependent manner to induce an inflammatory response
Authors: Chiou Ya‐Ling , Lin Ching‐Yuang
Published: March 2009

Der p2 is a major allergen from Dermatophagoides pteronyssinus, the main species of house dust mite and a major inducer of asthma, inducing harmful respiratory inflammatory responses by activating cells in the respiratory tract, leading to an unstable status. We hypothesize that Der p2 may induce local inflammatory responses by directly affecting airway smooth muscle (ASM) cells. In this study, we demonstrated that Der p2 raised nuclear factor‐kappa B (NF‐κB) and extracellular signal‐regulated kinase (ERK) 1/2 activation and induced a high level of proinflammatory cytokines expression in primary cultured ASM cells. Der p2 activated the MyD88 signaling pathway through toll‐like receptor (TLR) 2, not through TLR4. Notably, Der p2 stimulated ASM cells to increase phosphorylation of ERK1/2 and expression of c‐Fos, which were also important in the T helper type 2 (Th2) immune response. These results suggest that Der p2 induces asthma through the MyD88 signaling pathway in respiratory tissue. J. Cell. Physiol. 220: 311–318, 2009. © 2009 Wiley‐Liss, Inc.
Long‐term transduction of miniature pig parotid glands using serotype 2 adeno‐associated viral vectors
Authors: Hai Bo , Yan Xing , Voutetakis Antonis , Zheng Changyu , Cotrim Ana P. , Shan Zhaochen , Ding Gang , Zhang Chunmei , Xu Junji , Goldsmith Corinne M. , Afione Sandra , Chiorini John A. , Baum Bruce J. , Wang Songlin
Published: March 2009

Background

Previously, using an adenoviral vector, we showed that miniature pigs could provide a valuable and affordable large animal model for pre‐clinical gene therapy studies to correct parotid gland radiation damage. However, adenoviral vectors lead to short‐term transgene expression and, ideally, a more stable correction is required. In the present study, we examined the suitability of using a serotype 2 adeno‐associated viral (AAV2) vector to mediate more stable gene transfer in the parotid glands of these animals.

Methods

Heparan sulfate proteoglycan was detected by immunohistochemistry. β‐galactosidase expression was determined histochemically. An AAV2 vector encoding human erythropoietin (hEpo) was administered via Stensen's duct. Salivary and serum hEpo levels were measured using an enzyme‐linked immunosorbent assay. Serum chemistry and hematological analyses were performed and serum antibodies to hEpo were measured throughout the study. Vector distribution was determined by a quantitative polymerase chain reaction.

Results

Transgene expression was vector dose‐dependent, with high levels of hEpo being detected for up to 32 weeks (i.e. the longest time studied). hEpo reached maximal levels during weeks 4–8, but declined to approximately 25% of these values by week 32. Haematocrits were elevated from week 2. Transduced animals exhibited low serum anti‐hEpo antibodies (1 : 8–1 : 16). Vector biodistribution at animal sacrifice revealed that most copies were in the targeted parotid gland, with few being detected elsewhere. No consistent adverse changes in serum chemistry or hematology parameters were seen.

Conclusions

AAV2 vectors mediate extended gene transfer to miniature pig parotid glands and should be useful for testing pre‐clinical gene therapy strategies aiming to correct salivary gland radiation damage. Copyright © 2009 John Wiley & Sons, Ltd.
Poverty and environment links: An illustration from Africa
Authors: Comim Flavio , Kumar Pushpam , Sirven Nicolas
Published: March 2009

The impact of environmental change on the incidence of poverty through the changes in the livelihood options is expected to be significant. The resilience and condition of environment and ecosystems to deliver services within vulnerable regions is quite often crucial for ensuring livelihood security for the poor. However, understanding the links between poverty and environment (P&E) is a hard task. Even harder is to think about how to capture the links in the format of indicators. But this is the main objective of this paper. More specifically, the paper explores the implications of a new methodology for examining the links between different constituents of well‐being (in which poverty is understood as an unacceptable deprivation of multidimensional well‐being) and ecosystem services. The proposed methodology is based on the use of econometrics and adjustment factors. Focusing on the particular environmental problems presented in Africa, the paper delves into the links between livelihoods and capabilities, providing an encompassing framework for suggesting solutions for poverty reduction in this continent. Copyright © 2009 John Wiley & Sons, Ltd.
Key central pattern generators of the spinal cord
Authors: Guertin Pierre A. , Steuer Inge
Published: March 2009

In the central nervous system (CNS), central pattern generators (CPGs) are generally considered as specialized networks that can produce oscillatory motor output in the absence of any oscillatory input. For instance, respiration and mastication are among the critical biological functions well known to be controlled by such specialized networks. Several other CPGs have also been found specifically in the spinal cord. Among them, the CPG for locomotion is probably the most extensively studied rhythm‐ and pattern‐generating network of the CNS. Other, less completely understood CPGs have also been associated with the control of scratching, micturition, and ejaculation. This review provides a brief update on CPG organization and function in the spinal cord and focuses on similarities and differences between these networks and their pharmacological modulation. © 2009 Wiley‐Liss, Inc.
Identification and functional characterization of the promoter of the mouse sodium‐activated sodium channel Nax gene (Scn7a)
Authors: García‐Villegas Refugio , López‐Álvarez Luz E. , Arni Stephan , Rosenbaum Tamara , Morales Marco A.
Published: March 2009

Nax is a sodium channel, thought to be a descendant of the voltage‐gated sodium channel family. Nevertheless, Nax is not activated by voltage but rather by augmentation of extracellular sodium over 150 mM. In the brain, it is localized to the circumventricular organs, important regions for salt and water homeostasis in mammals, where it operates as a sodium‐level sensor of body fluid. Nax channel is expressed in lung, uterus, and heart, and it is also found in trigeminal and dorsal root ganglia and in nonmyelinating Schwann cells, where its physiological role remains unclarified. Here we identified the promoter and transcription start sites of Nax sodium channel in dorsal root ganglia neurons from mouse. We report a characterization of the basal TATA‐less promoter and the sequence requirements for promoter activity in Neuro 2A neuroblastoma cells and in dorsal root ganglia neurons, where basal promoter activity seems to require NGFI‐C and Ebox DNA elements. Finally, we provide evidence that a repression mechanism that inhibits Nax expression may be present in certain tissues. These findings provide the basis with which to understand tissue‐specific regulation of Nax sodium channel gene (Scn7a) expression. © 2009 Wiley‐Liss, Inc.
An Eulerian particle level set method for compressible deforming solids with arbitrary EOS
Authors: Mehmandoust B. , Pishevar A.‐R.
Published: March 2009

In this study, an Eulerian, finite‐volume method is developed for the numerical simulation of elastic–plastic response of compressible solid materials with arbitrary equation of state (EOS) under impact loading. The governing equations of mass, momentum, and energy along with evolution equations for deviatoric stresses are solved in Eulerian conservation law form. Since the position of material boundaries is determined implicitly by Eulerian schemes, the solution procedure is split into two separate subproblems, which are solved sequentially at each time step. First, the conserved variables are evolved in time with appropriate boundary conditions at the material interfaces. In the present work a fourth‐order central weighted essentially non‐oscillatory shock‐capturing method that was developed for gas dynamics has been extended to high strain rate solids problems. In this method fluxes are determined on a staggered grid at places where solution is smooth. As a result, the method does not rely on the solution of Riemann problems but enjoys the flexibility of using any type of EOS. Boundary conditions at material interfaces are also treated by a special ghost cell approach. Then in the second subproblem, the position of material interfaces is advanced to the new time using a particle level set method. A fifth‐order Godunov‐type central scheme is used to solve the Hamilton–Jacobi equation of level sets in two space dimensions. The capabilities of the proposed method are evaluated at the end by comparing numerical results with the experimental results and the reported benchmark solutions for the Taylor rod impact, spherical groove jetting, and void collapse problems. Copyright © 2009 John Wiley & Sons, Ltd.
Experimenting with organisational development in Bhutan: A tool for reform and the achievement of multi‐level goals?
Authors: O'Flynn Janine , Blackman Deborah
Published: March 2009

In this article we present a unique study of how a nation, Bhutan, is using a specific change management approach—organisational development—as the lever for system‐level change in pursuit of a complex, multi‐level suite of goals to, ultimately, enhance Gross National Happiness (GNH). We argue that this represents one of the first attempts at using OD for wide‐scale change, something hinted at decades ago, and flagged by recent work coming out of the United Nations Development Program and civil society organisations (CSOs). Conceptually, we point to a high level of fit between the Bhutanese development philosophy and OD, and argue there is great potential for using OD in the context. However, we raise a series of issues around the practical feasibility of this approach highlighting important points of tension which pose major challenges for the Bhutanese experiment. Copyright © 2009 John Wiley & Sons, Ltd.
A novel approach to prepare PBT nanocomposites with elastomer‐modified SiO2 particles
Authors: Zhang Ling , Hong Yuerong , Zhang Tianshui , Li Chunzhong
Published: March 2009

Poly(butylenes terephthalate) (PBT)/SiO2 nanocomposites with uniform dispersion, strong interfacial adhesion, and improved mechanical properties have been prepared by a novel approach. Ethylene‐methyl acrylate‐glycidyl methacrylate (E‐MA‐GMA) elastomer chains were first chemically grafted onto the surface of SiO2 nanoparticles. Fourier transform infrared spectra result shows that elastomer‐modified SiO2 nanoparticles exhibit absorption at 2963–2862 cm−1 of the stretching modes of CH, which suggests the reaction between the hydroxyl groups of SiO2 surface and epoxy groups of E‐MA‐GMA. And the binding energy of Si2p and O1s of the elastomer‐modified SiO2 shifts to lower binding energy, which further confirms the formation of SiOC bonds. This surface treatment allows SiO2 nanoparticles homogeneously dispersing in PBT matrix. The morphology with loose aggregates contains networked SiO2 particles with an interparticle distance ranging from 0 to 30 nm. As a result, the storage modulus and the tensile properties of PBT/E‐MA‐GMA‐SiO2 nanocomposites are higher than those of pure PBT and PBT with untreated SiO2. The incorporation of E‐MA‐GMA‐modified SiO2 particles increases the tensile strength and modulus to 58.4MPa and 2661MPa respectively, which is 8% and 16% higher than those of pure PBT. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Herbal products use during pregnancy: prevalence and predictors
Authors: Moussally Krystel , Oraichi Driss , Bérard Anick
Published: March 2009

Purposes

(1) Measure the prevalence of herbal product (HP) use, alone, and concomitantly with prescribed medications during pregnancy, (2) identify the most frequently consumed HP during gestation and (3) determine predictors of HP use at the beginning of pregnancy, and during the third trimester.

Methods

A questionnaire was mailed to 8505 women selected from the Quebec Pregnancy Registry which was created by the linkage of three administrative databases: RAMQ, Méd‐Echo and ISQ. Women were eligible if they were continuously insured by the RAMQ drug plan for at least 12 months before the first day of gestation and during pregnancy, and if they gave birth to a live born between January 1998 and December 2003 in one of the Quebec's hospitals. Women with diabetes and psychoses, and women who delivered a baby with birth defects were selected first. Descriptive statistics and multivariate logistic regression models were used to analyse data.

Results

Of the 3354 women (39%) who answered the questionnaire, and were included in the study, nine per cent used HP during pregnancy. 69% of users took at least one prescribed medication concomitantly. Chamomile, green tea, peppermint and flax were the most frequently HP used. Multivariate analyses showed that body mass index (BMI), multivitamin use and one to three prescribed medications used before pregnancy were predictors of HP use at the beginning of pregnancy; adherent women, smokers and users of HP prior to pregnancy were predictors of HP use during the third trimester.

Conclusion

HP use alone and concomitantly with prescribed medications during pregnancy is common, and needs to be addressed by health professionals. Copyright © 2009 John Wiley & Sons, Ltd.
Grafting of glycidyl methacrylate onto swift‐nickel‐ions irradiated polypropylene films using chemical initiator
Authors: Chawla S. , Ghosh A.K. , Avasthi D.K. , Kulriya P.K. , Ahmad S.
Published: March 2009

Polypropylene (PP) films were irradiated with swift nickel ions, (90 MeV Ni8+ ions) at different fluencies varying from 1010 to 3 × 1011 ions/cm2 and then grafted with glycidyl methacrylate (GMA) using benzoyl peroxide (BPO) as chemical initiator. It is shown that GMA could be grafted onto PP film. A comparison for the GMA grafting using BPO initiator in virgin as well as in the swift nickel ions irradiated PP films was given. The exposure of PP film to SHI results in a reduction in the effect of the BPO for graft copolymerization. Furthermore, as the fluency of swift nickel ions increased beyond an optimum value, the overlapping of the latent tracks reduced the grafting yield. Contact angle measurements and surface energy calculations showed an increasing hydrophilic nature in the direction from pure PP to grafted PP‐g‐GMA. These results are intended to benefit the synthesis and properties of a functional polymer. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Structural and electrical properties of V‐modified Pb(Fe0.5Nb0.5)O3 ceramics
Authors: Sahoo Subhadarsani , Choudhary R. N. P. , Mathur B. K.
Published: March 2009

Polycrystalline samples of Pb(Fe0.5Nb0.5–x Vx)O3, x = 0, 0.05, 0.10, 0.15 were synthesized by a mixed oxide technique. Preliminary structural analysis suggests that the compounds have been formed in single‐phase monoclinic crystal system. Incorporation of V+5 in place of Nb+5 significantly reduces the sintering temperature of the compounds. Scanning electron micrographs of the compounds show that the grains are uniformly and densely distributed over the entire surface of the samples. Detailed studies of dielectric properties (dielectric constant and tangent loss) as a function of frequency (103–106 Hz) and temperature (50–300) °C suggest that Pb(Fe0.5Nb0.5–x Vx)O3 x = 0.0, 0.05 undergoes a ferroelectric–paraelectric phase transition. The phase transition in these compositions has been confirmed with the polarisation measurement. For the composition x = 0.10 and 0.15 ferroelectric phase transition vanishes due the grain size reduction. The presence of loss anomaly at high temperature in all V‐doped Pb(Fe0.5Nb0.5)O3 is related to the charge hopping relaxation. On increase in vanadium content in PFN the grain size reduces below the critical value for ferroelectricity to vanish. The ac conductivity of the compounds was found to increase on increasing temperature suggesting NTCR behavior of the materials. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Casimir force between two parallel semiconductor slabs: Magnetic field effects in the Voigt geometry
Authors: García‐Serrano R. , Martínez G. , Hernández P. H. , Palomino‐Ovando M. , Cocoletzi Gregorio H.
Published: March 2009

We investigate the Casimir force F between two parallel semiconductor slabs taking into account magnetoplasmon effects. For our calculations we consider an external magnetic field applied in the Voigt geometry. Studies are carried out using the formula of F, which is written in terms of the reflectivities of the incident electromagnetic (EM) waves onto the surfaces of the semiconductor slabs, in the vacuum gap between slabs. Results show that the Casimir force depends strongly on the slab thickness as well as on the magnetic‐field strength (or equivalently on the cyclotron frequency). At a constant cyclotron frequency and for small slab thickness F/F0 (F0 is the ideal force) displays a dip at small separation distances L between slabs. F/F0 increases with L up to saturation as the slab thickness increases. The curve with the strongest value of F/F0 corresponds to the semi‐infinite medium geometry. For a constant slab thickness and small cyclotron frequency, F/F0 as a function of L shows a monotonic increase as L increases, and eventually reaches saturation. At high cyclotron frequency F/F0 displays a dip. The curve of F/F0 with no applied external field corresponds to the one with the strongest Casimir force. Therefore, magnetoplasmon effects, with an applied magnetic field in the Voigt geometry may inhibit the Casimir force. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The most probable structures of platinum nitride as a function of composition
Authors: Soto Gerardo , Moreno‐Armenta Maria G.
Published: March 2009

So far two methods have been successful for the production of platinum nitride. One is the laser ablation method, the other the high‐temperature high‐pressure method. Spectroscopic examinations of films produced by the first method reveal that nitrogen is in interstitial sites of platinum as N1 units. In contrast, the accepted configuration for the material grown by the second method is that nitrogen is as N2 units in a pyrite‐like PtN2 structure. To elucidate these conflicting results we carried out density functional calculations to correlate composition with nitrogen sites in PtNx . We found that for dilute nitrogen concentrations, x < 0.2, nitrogen is in six‐fold coordinated sites (octahedral interstices) as N1 units. For 0.2 < x < 1.5, nitrogen is in tetrahedral interstices as N1 units. Only for x > 1.5 is the N2 configuration in octahedral sites attained. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Room‐temperature ferromagnetism of Cu‐doped ZnO films deposited by helicon magnetron sputtering
Authors: Ran Fan‐Yong , Imaoka Masao , Tanemura Masaki , Hayashi Yasuhiko , Herng Tun‐Seng , Lau Shu‐Ping
Published: March 2009

Wurtzite structure ZnO films doped with 0.5 and 1.7 at% Cu were deposited by helicon magnetron sputtering. The prepared films exhibited room‐temperature (RT) ferromagnetism (FM). Maximum RT saturation magnetization of 2 emu/cm3 (∼0.3μB/Cu) was observed for ZnO film with 1.7 at% Cu. Cu ions were in a bivalent state as identified by X‐ray photoelectron spectroscopy (XPS). In photoluminescence spectra, the green emission peak increased and redshifted due to the incorporation of Cu or defects induced by Cu incorporation. Since Cu and Cu‐related oxides are not RT ferromagnetic, and no trace of ferromagnetic contamination was detected in XPS results, the observed FM is considered to be an intrinsic property of Cu‐doped ZnO films. The FM was thought to originate from defect‐related mechanisms. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Propensity scores and M‐structures
Authors: Sjölander Arvid
Published: April 2009

In a recent issue of Statistics in Medicine, Ian Shrier [Statist. Med. 2008; 27(14):2740–2741] posed a question regarding the use of propensity scores [Biometrika 1983; 70(1):41–55]. He considered an ‘M‐structure’ illustrated by the directed acyclic graph (DAG) in Figure 1. In Figure 1, z is a binary exposure, r is a response of interest, x is a measured covariate, and u1 and u2 are two unmeasured covariates. Shrier stated that for the M‐structure, ‘... it remains unclear if the propensity method described by Rubin would introduce selection bias or not’. In the same issue, Donald Rubin [Statist. Med. 2002; 27(14):2741–2742] replied by clarifying several key points in the use of propensity scores. He did not, however, discuss the original question posed by Shrier. Given the popularity of both propensity score methods and graphical models, I think any confusion regarding the appropriateness of these methods deserves serious attention and I would therefore like to answer Shrier's question here. The short answer is that for the M‐structure, propensity score methods do indeed induce a bias. Below, I will clarify this statement. I will first briefly review the basic idea of propensity scores and then explain why the idea does not apply to the M‐structure. I will use a notation which is consistent with Rosenbaum and Rubin [Biometrika 1983; 70(1):41–55]. Copyright © 2009 John Wiley & Sons, Ltd.
Non‐inferiority tests for clustered matched‐pair data
Authors: Nam Jun‐mo , Kwon Deukwoo
Published: March 2009

Non‐inferiority tests for matched‐pair data where pairs are mutually independent may not be appropriate when pairs are clustered. The tests may require an adjustment to account for the correlation within a cluster. We consider the adjusted score and Wald‐type tests, and a modification of Obuchowski's method for non‐inferiority and compare them with the non‐inferiority test based on a method of moments estimate in terms of Type 1 error rate and power by simulations for a small cluster size under various correlation structures. In general, the score test adjusted by an inflation factor and the modified Obuchowski's method perform as good as the test based on moments estimate in the accuracy of Type 1 error rates. The latter does not provide reasonably close Type 1 error rates to the nominal level when the number of clusters is 25 or smaller and a positive response rate for the standard procedure is 20 per cent or lower. The adjusted score test, the method based on moments estimate and the modified test are comparable in power. The adjusted Wald‐type test is too anti‐conservative and we should caution use of the test. Since number of clusters is strongly related to the accuracy of empirical Type 1 error rate and power, it is very important to have a sufficiently large number of clusters in designing a clustered matched‐pair study for non‐inferiority. Published in 2009 by John Wiley & Sons, Ltd.
Three‐dimensional sonographic calculation of the volume of intracranial structures in growth‐restricted and appropriate‐for‐gestational age fetuses
Authors: Benavides‐Serralde A. , Hernández‐Andrade E. , Fernández‐Delgado J. , Plasencia W. , Scheier M. , Crispi F. , Figueras F. , Nicolaides K. H. , Gratacós E.
Published: March 2009

Objectives

To evaluate the feasibility and reproducibility of volume segmentation of fetal intracranial structures using three‐dimensional (3D) ultrasound imaging, and to estimate differences in the volume of intracranial structures between intrauterine growth‐restricted (IUGR) and appropriate‐for‐gestational age (AGA) fetuses.

Methods

Total intracranial, frontal, thalamic and cerebellar volumes were measured using 3D ultrasound imaging and Virtual Organ Computer‐aided AnaLysis (VOCAL) in 39 IUGR and 39 AGA fetuses matched for gestational age, at 28–34 weeks of gestation. Volumes of, and ratios between, structures were estimated, and differences between IUGR and AGA fetuses were calculated. Volume measurements were performed by two observers, and interobserver and intraobserver intraclass correlation coefficients (ICCs) were calculated for each structure.

Results

Volumes were satisfactorily obtained in all fetuses. All net volumes except those for the thalamus (P = 0.23) were significantly smaller (P = 0.001) in IUGR fetuses. After adjusting volumes for biparietal diameter the frontal volume was significantly smaller (P = 0.02) and the thalamic volume significantly greater (P = 0.03) in IUGR fetuses than in AGA fetuses. Significant intergroup differences in the ratios between structures were found only in those involving the frontal region. Interobserver ICCs were as follows: total intracranial 0.97 (95% CI, 0.92–0.98), cerebellar 0.69 (95% CI, 0.44–0.75), frontal 0.66 (95% CI, 0.42–0.79) and thalamic 0.54 (95% CI, 0.37–0.72).

Conclusions

IUGR fetuses show differences in the volume of intracranial structures compared with AGA fetuses, with the largest difference found in the frontal region. These differences might be explained by in‐utero processes of neural reorganization induced by chronic hypoxia. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Analysis of paintings from the nineteenth century Brazilian painter Rodolfo Amoedo using EDXRF portable system
Authors: Calza Cristiane , Pedreira Andrea , Lopes Ricardo Tadeu
Published: March 2009

The pigments used in four of the most representative paintings of the Brazilian artist Rodolfo Amoedo were characterized by means of the EDXRF technique. The analyzed paintings were ‘The Last Tamoyo’ (1883), ‘Study of a Woman’ (1884), ‘Bust of Mrs. Amoedo’ (1892) and ‘Bad News’ (1895). EDXRF measurements were carried out with a portable system developed by the Nuclear Instrumentation Laboratory, consisting of an x‐ray tube Oxford TF3005 with a W anode, operating at 25 kV and 100 µA, and a Si‐PIN XR‐100CR detector from Amptek. Several spectra were obtained in each color and distinct hue of the paint layer, with an acquisition time of 300 s and a beam collimation of 2 mm. Some pigments used by the artist were zinc white, lead white, ochre, umber, vermilion, Prussian blue, cobalt blue, cadmium yellow, black iron oxide and manganese violet. In the painting ‘The Last Tamoyo’, titanium white was identified in some alteration areas, which were restored during the twentieth century. These results—together with computed radiography analyses—will be used to create a database about the nineteenth‐century collection of the National Museum of Fine Arts, in order to assist restorers, conservators, art students and researchers in the field of archeometry. Copyright © 2009 John Wiley & Sons, Ltd.
When X‐inactivation meets pluripotency: An intimate rendezvous
Authors: Navarro Pablo , Avner Philip
Published: March 2009

The integration of X‐inactivation with development is a crucial aspect of this classical paradigm of epigenetic regulation. During early female mouse development, X‐inactivation reprogramming occurs in pluripotent cells of the inner cell mass of the blastocyst and in pluripotent primordial germ cells. Here we discuss the developmental strategies which ensure the coupling of the regulation of X‐inactivation to the acquisition of pluripotency through the regulation of the master of X‐inactivation, the non‐coding Xist gene, by the key factors which support pluripotency Nanog, Oct4 and Sox2.
Cortisol and antisocial behavior in early adolescence: The role of gender in an economically disadvantaged sample
Authors: Kobak Roger , Zajac Kristyn , Levine Seymour
Published: April 2009

This study examines the relation between adolescents' antisocial behaviors and adrenocortical activity during a laboratory visit in a sample of economically disadvantaged families (N= 116, ages 12–14, 51% female). Pretask cortisol levels indexed adolescents' prechallenge response to the lab visit, whereas adolescents' response to a conflict discussion with their caregivers was indexed with residualized change in pre- to postconflict cortisol levels. A trait measure of antisocial behavior (derived from parent, teacher, and self-reports) was associated with lower pretask cortisol levels but greater cortisol response to the conflict discussion. Gender moderated antisocial adolescents' cortisol response to the conflict discussion with girls who reported more covert risky problem behaviors showing an increased cortisol response. The findings suggest that, although antisocial adolescents had lower pretask cortisol levels, conflict discussions with caregivers present a unique challenge to antisocial girls compared with antisocial boys.
Gravity wave characteristics observed over a tropical station using high‐resolution GPS radiosonde soundings
Authors: Nath Debashis , Venkat Ratnam M. , Jagannadha Rao V. V. M. , Krishna Murthy B. V. , Vijaya Bhaskara Rao S.
Published: March 2009

Several investigations of the dominant period gravity waves (GWs) were conducted earlier using Indian mesosphere‐stratosphere‐troposphere (MST) radar located at Gadanki (13.5°N, 79.2°E). However, these works had their own limitations of unavailability of continuous data, low SNR, and lack of reliable data at the stratospheric heights (in the case of MST radar) and low spatial resolution (for routine balloon data). For the present study, high‐resolution GPS radiosonde data for more than 2 years (2006–2008) has been used for the first time to characterize the dominant GWs and their associated source mechanisms. Particular attention is paid (1) to check the consistency in GW characteristics observed with MST radar, (2) to estimate potential energy, kinetic energy, and hence total energy, (3) to extend the analysis up to 25 km and check whether vertical wavelength is the same as that observed by MST radar in the lower stratosphere, and finally (4) to estimate the exact direction of propagation in horizontal, which was not possible from MST radar alone. Clear semiannual variation in GW energy, with maximum during monsoon and winter and minimum during premonsoon and postmonsoon in the troposphere, is noticed during 2006 but not clear in 2007. Annual variation is observed in the lower stratosphere with maximum during monsoon (winter enhancement is not significant) season. Strong eastward shear due to tropical easterly jet and orography is found to be responsible for generating the GWs during the monsoon and winter, respectively. Although several features are consistent with that observed earlier, a few new features have been observed by GPS radiosonde and are reported in the present study.
Fluxes of Al, Fe, Ti, Mn, Pb, Cd, Zn, Ni, Cu, and As in monthly bulk deposition over the Pyrenees (SW Europe): The influence of meteorology on the atmospheric component of trace element cycles and its implications for high mountain lakes
Authors: Bacardit Montserrat , Camarero Lluís
Published: March 2009

The atmospheric bulk (wet plus dry) deposition of trace elements was measured monthly at Lake Redon (2240 m above sea level, Central Pyrenees, Spain) in 2004–2006. Aluminum, Ti, Fe, Mn, and As were part of the dust carried from the Iberian Peninsula and North Africa: these elements presented low enrichment factors and occurred (except Mn) as particles. Lead, Zn, Cd, and Cu showed a polluting character: their enrichment factors were clearly above those that can be caused by natural fractionation processes; and they were found in a variable, though always large proportion as soluble forms. Nickel had intermediate properties suggesting a balance of both natural and polluting sources. Temporal variations of trace element deposition were related to the prevailing meteorological conditions. Deposition of dust, Pb, Ni, and Cd was higher during the year in which a larger proportion of precipitation came from the Iberian Peninsula–North Africa and followed low‐altitude trajectories. On a seasonal scale, deposition of dust and Pb was similarly related to southern air masses occurring during June–November. Possible changes in the general atmospheric circulation patterns as a result of climate change may cause a shift in the proportion of air masses coming from different locations and hence in the fluxes of the elements received by the catchments. Such atmospheric fluxes have caused high concentrations of several trace elements in Pyrenean lake sediments at a level which may be of ecotoxicological relevance.
Along‐strike differences in the Southern Alps of New Zealand: Consequences of inherited variation in rheology
Authors: Upton Phaedra , Koons Peter O. , Craw Dave , Henderson C. Mark , Enlow Ray
Published: March 2009

Long‐ and short‐term strain variations along the Australian‐Pacific plate boundary through the South Island of New Zealand, including a 300% increase in orogen width, coexistence of oblique thrusting on orthogonal structures, and variability in the locus of orogenic gold deposits, coincide with rheologically relevant geological variation. Our model investigates the consequences of thin, strong lower crust in the north and thick, weak lower crust in the south. Solution of the full 3‐D mechanical equations reproduces the larger wavelength strain patterns of the orogen. A 3‐D perturbation‐based analytical solution leads to the identification of the sensitivity of displacement type to minor stress changes. Transition from boundary‐normal thrusting to boundary‐parallel thrusting occurs at the transition from strong to weak lower crust and is related to an increase in either τyz (shear stress in the yz plane) or the ratio of the coordinate normal stresses, (σyy/σxx), where x and y are in the horizontal and z is vertical. Both mechanisms are compatible with the geologically dependent rheological variation employed in our model.
Decadal change in intraseasonal variability over the South China Sea
Authors: Kajikawa Yoshiyuki , Yasunari Tetsuzo , Wang Bin
Published: March 2009

Evidence is presented to reveal a decadal change around mid‐1990s in the behavior of intraseasonal variability (ISV) over the South China Sea (SCS). During 1979–1993, the ISV has a spectral peak around 64 days, which is longer than in the recent epoch of 1994–2007 (around 42 days). The ISV event in 1979–1993 involves a merging process of the northward and westward propagating convection anomalies over the western North Pacific. The ISV in 1994–2007 has no such a merging process but exhibits a tilted band structure extending from the northern Indian Ocean to the SCS, which is strongly connected to the equatorial eastward propagating Madden‐Julian Oscillation. The merging process during 1979–1993 modified the ISV over the SCS, resulting in the prolonged period, enhanced convective activity and a weakened relationship with the eastward propagating MJO. The possible cause of this change is discussed.
Time of emergence (TOE) of GHG‐forced precipitation change hot‐spots
Authors: Giorgi Filippo , Bi Xunqiang
Published: March 2009

The Time Of Emergence (TOE) of 14 greenhouse gas (GHG) ‐ forced precipitation change hotspots (PSPOTs) is identified from the CMIP3 multi‐model ensemble. The TOE is defined as the time in 21st century projections at which the magnitude of the ensemble mean precipitation change signal becomes greater than the uncertainty due to the inter‐model spread and the internal model multi‐decadal variability. Of the 14 PSPOTS identified, 6 have a TOE in the early decades of the 21st century (northern high latitudes, Mediterranean, and East Africa), 3 in the mid decades (East and South Asia, Caribbean) and 5 in the late decades or beyond (South Africa, Western United States, Amazon Basin, Southern Australia, Central America). The TOE is sensitive to the GHG emission scenario for some of the PSPOTS. The TOE has important implications for the predictability and detection of GHG‐forced PSPOTS and for impact and adaptation studies.
Entropic Landscape: the method to predict folding patterns and regional stability of proteins
Authors: Onizuka Kentaro
Published: March 2009

I propose a new method to calculate the entropy of a given protein sequence fragment. The set of fragment entropies over all possible fragments of the given sequence shows which region of the sequence is statistically stable and which region has a strong desire to fold into particular conformations. Here are three methods to calculate fragment entropy, the results from each of which represent entropies of different stage of protein folding.
Social Stress, Visceral Obesity, and Coronary Artery Atherosclerosis in Female Primates
Authors: Shively Carol A. , Register Thomas C. , Clarkson Thomas B.
Published: March 2009

Our previous work in cynomolgus monkeys demonstrated significant relationships between (i) social reorganization stress and visceral fat deposition, and (ii) central fat deposition and coronary artery atherosclerosis (CAA). Nevertheless, direct relationships between CAA and visceral fat have not been demonstrated in people or animals, nor have relationships among stress, visceral obesity, and CAA been observed within a single study. Here, we examine the hypothesis that visceral obesity provides a link between social stress and CAA. Subjects were 41 socially housed females that consumed an atherogenic diet for 32 months. Social behavior and ovarian function were continuously recorded; dexamethasone suppression tests, telemetered overnight heart rate, BMI, visceral (VAT) and subcutaneous abdominal (SAT) adipose tissue were measured before necropsy. Females with high VAT:SAT were relatively subordinate, socially isolated, received more aggression and less grooming, desensitized to circulating glucocorticoids, had impaired ovarian function, higher heart rates late in the day, and more CAA than low VAT:SAT females. High‐BMI females had higher heart rates than low‐BMI females. Poor ovarian function in high VAT:SAT females is a novel observation suggesting the need for studies of fat distribution and ovarian function in women. The results of this study are the first to demonstrate a relationship between CAA and visceral obesity, and suggest that social stress may exacerbate CAA in part by increasing the ratio of visceral:subcutaneous fat mass in selected individuals susceptible to diet‐induced CAA. Further studies are needed to understand the complex and multifactorial temporal relationship among relative visceral obesity, physiological stress responses, and CAA.
Proximity effects in asymmetric layered ferromagnet/superconductor nanostructures
Authors: Fazleev N. G. , Proshin Y. N. , Khusainov M. G.
Published: March 2009

The asymmetric four-layered F′/S′/F″/S″ nanostructure consisting of rather dirty superconducting (S) and ferromagnetic (F) metals is studied within the theory of the proximity effect taking detailed account of the boundary conditions. The new π phase superconducting states are obtained for the F′/S′/F″/S″ structure in addition to the known “superlattice” states. The dependence of critical temperatures versus the F layer thicknesses is explored for a wide range of parameters. Decoupled superconductivity is predicted for this nanostructure and an optimal set of parameters is determined for which the difference between the critical temperatures for different states becomes significant. The complicated phase diagram of the asymmetric four-layered F′/S′/F″/S″ nanostructure is constructed, explored, and compared with the ones for F/S bilayers, symmetric F/S/F and S/F/S trilayers, and F/S superlattices.
Interlayer coupling and switching field of exchange coupled media
Authors: Pandey K. K. M. , Chen J. S. , Chow G. M. , Hu J. F. , Lim B. C.
Published: March 2009

The effects of interlayer coupling on switching field and magnetization reversal mechanism of Co72Pt28–SiO2(hard)/Co–SiO2(soft) exchange coupled media were investigated. The soft layer, with thickness less than the domain wall width, followed domain wall assisted switching mechanism for direct interlayer coupling between the hard and soft layers. It was effective in significantly reducing the switching field. The strength of interlayer coupling between the hard and soft layers was controlled by inserting the Pt intermediate layer between them. The reduced interlayer coupling led to independent switching of the hard and the soft layer and was ineffective in reducing the switching field.
Photoluminescence study of polycrystalline photovoltaic CdS thin film layers grown by close-spaced sublimation and chemical bath deposition
Authors: Abken Anke E. , Halliday D. P. , Durose Ken
Published: March 2009

Photoluminescence (PL) measurements were used to study the effect of postdeposition treatments by annealing and CdCl2 activation on polycrystalline CdS layer grown by close-spaced sublimation (CSS) and chemical bath deposition (CBD). CdS films were either annealed in a temperature range of 200–600 °C or CdCl2 treated between 300–550 °C. The development of “red,” “intermediate orange,” “yellow,” and “green” luminescence bands is discussed in comparison with PL assignments found in literature. PL spectra from CdS layer grown by CSS are dominated by the yellow band with transitions at 2.08 and 1.96 eV involving (Cdi-A), (VS-A) complex states where A represents an acceptor. Green luminescence bands are observed at 2.429 and 2.393 eV at higher annealing temperature of 500–600 °C or CdCl2 treatment above 450 °C, and these peaks are associated with zero and a longitudinal optical phonon replica of “free-to-bound” transitions. As grown CBD-CdS films show a prominent red band with four main peaks located at 1.43, 1.54, 1.65, and 1.77 eV, believed to be phonon replicas coupled with local vibrational modes. This remains following postdeposition treatment. The red luminescence is associated with VS surface states and in the case of CdCl2 treatment with (VCd-ClS) centers. Postdeposition treatments of CBD and CdS promote the evolution of an intermediate orange band at 2.00 eV, most likely a donor-acceptor pair, and a yellow band at 2.12 eV correlated with (Cdi-VCd) centers. The green luminescence bands observed at 2.25 and 2.34 eV are associated with transitions from deep donor states (e.g., Cdi) to the valence band. These states form due to crystallinity enhancement and lattice conversion during annealing or CdCl2 activation. Observed changes in PL bands provide detailed information about changes in radiative recombination centers in CdS layer, which are suggested to occur during device processing of CdTe/CdS thin film solar cells.
Measurement of high data rate performance in perpendicular magnetic recording
Authors: Lin Wen-chin , Zhu Jian-Gang , Pan Tao
Published: March 2009

Two-port network analysis is used to probe the dynamics of the perpendicular recording head. Two identical heads are aligned to each other with poletip to poletip on their air-bearing-surface sides, while the spacing is about the typical flying height. With two-port network analysis, forward transmission coefficient measurement shows the nonuniformity of the frequency response across the footprint of the poletip. It is suggested that the spatial distribution of the fast-field pulse can be optimized by constructing the fast write pulse with proper frequency components. In addition, the head-to-media recording performance is characterized by contact scanning recording tester. A single 0.15 ns/50 mA current pulse is good enough to complete the recording.
Development of wireless communication system in real-time internal radiation dose measurement system using magnetic field
Authors: Sato Fumihiro , Shinohe Kohta , Takura Tetsuya , Matsuki Hidetoshi , Yamada Syogo , Sato Tadakuni
Published: March 2009

In radiation therapy, excessive radiation occurs because the actual delivered dose to the tumor is unknown. To overcome this problem, we need a system in which the delivered dose is measured inside the body, and the dose data are transmitted from the inside to the outside of the body. In this study, a wireless communication system, using magnetic fields was studied, and an internal circuit for obtaining radiation dose data from an x-ray detector was examined. As a result, a communication distance of 200 mm was obtained. An internal circuit was developed, and a signal transmission experiment was performed using the wireless communication system. As a result, the radiation dose data from an x-ray detector was transmitted over a communication distance of 200 mm, and the delivered dose was determined from the received signal.
The role of the spin-density wave and disorder in the density of states of sputtered Cr films
Authors: Cooke David W. , Boekelheide Z. , Queen D. R. , Hellman F.
Published: March 2009

Chromium plays a key role as a spacer layer in the well-studied landmark giant magnetoresistive (GMR) system, Fe/Cr. In these multilayered structures, most often produced through sputtering, the density of Cr states at the Fe/Cr interface is known to contribute strongly to the spin-dependent scattering that gives rise to the GMR behavior. Chromium itself holds a wealth of information about antiferromagnetism due to its unique spin-density wave (SDW) behavior. By varying the preparation conditions, we examine how stress and disorder alter the SDW and the density of states of Cr. We measured the specific heat of various Cr films from 2 to 300 K using our unique thin film microcalorimeters. Analysis of the low temperature specific heat allowed us to determine the Debye temperature and the electronic specific heat coefficient γ, which is proportional to the density of states at the Fermi surface. Fitting the low temperature heat capacity data to a Debye model shows a clear phonon softening in the more highly disordered sputtered films. From this, we are able to extract the band structure density of states and the strength of the electron-phonon coupling. Though it has been shown that the commensurate and incommensurate SDWs carve out varying parts of the Fermi surface, we find that the density of states at the Fermi energy is much more sensitive to disorder broadening than to the various SDW phases.