bluuebunny/crossref_metadata_2025 huggingface dataset:
Forecast covariances in the linear multiregression dynamic model
Authors: Queen Catriona M. , Wright Ben J. , Albers Casper J.
Published: January 2008

The linear multiregression dynamic model (LMDM) is a Bayesian dynamic model which preserves any conditional independence and causal structure across a multivariate time series. The conditional independence structure is used to model the multivariate series by separate (conditional) univariate dynamic linear models, where each series has contemporaneous variables as regressors in its model. Calculating the forecast covariance matrix (which is required for calculating forecast variances in the LMDM) is not always straightforward in its current formulation. In this paper we introduce a simple algebraic form for calculating LMDM forecast covariances. Calculation of the covariance between model regression components can also be useful and we shall present a simple algebraic method for calculating these component covariances. In the LMDM formulation, certain pairs of series are constrained to have zero forecast covariance. We shall also introduce a possible method to relax this restriction. Copyright © 2008 John Wiley & Sons, Ltd.
Gas chromatography‐mass spectrometry with supersonic molecular beams
Authors: Amirav Aviv , Gordin Alexander , Poliak Marina , Fialkov Alexander B.
Published: January 2008

Gas chromatography‐mass spectrometry (GC‐MS) with supersonic molecular beams (SMBs) (also named Supersonic GC‐MS) is based on GC and MS interface with SMBs and on the electron ionization (EI) of vibrationally cold analytes in the SMBs (cold EI) in a fly‐through ion source. This ion source is inherently inert and further characterized by fast response and vacuum background filtration capability. The same ion source offers three modes of ionization including cold EI, classical EI and cluster chemical ionization (CI). Cold EI, as a main mode, provides enhanced molecular ions combined with an effective library sample identification, which is supplemented and complemented by a powerful isotope abundance analysis method and software. The range of low‐volatility and thermally labile compounds amenable for analysis is significantly increased owing to the use of the contact‐free, fly‐through ion source and the ability to lower sample elution temperatures through the use of high column carrier gas flow rates. Effective, fast GC‐MS is enabled particularly owing to the possible use of high column flow rates and improved system selectivity in view of the enhancement of the molecular ion. This fast GC‐MS with SMB can be further improved via the added selectivity of MS‐MS, which by itself benefits from the enhancement of the molecular ion, the most suitable parent ion for MS‐MS. Supersonic GC‐MS is characterized by low limits of detection (LOD), and its sensitivity is superior to that of standard GC‐MS, particularly for samples that are hard for analysis. The GC separation of the Supersonic GC‐MS can be improved with pulsed flow modulation (PFM) GC × GC‐MS. Electron ionization LC‐MS with SMB can also be combined with the Supersonic GC‐MS, with fast and easy switching between these two modes of operation. Copyright © 2008 John Wiley & Sons, Ltd.
Evidences for charge‐transfer complex formation in the benzene adsorption on sulfated TiO2–a resonance Raman spectroscopy investigation
Authors: Noda L. K. , Rosales R. , Gonçalves N. S. , Sala O.
Published: January 2008

Benzene adsorbed on highly acidic sulfated TiO2 (S‐TiO2) shows an intriguing resonance Raman (RR) effect, with excitation in the blue‐violet region. There are very interesting spectral features: the preferential enhancement of the e2g mode (1595 cm−1) in relation to the a1g mode (ring‐breathing mode at 995 cm−1) and the appearance of bands at 1565 and 1514 cm−1. The band at 1565 cm−1 is probably one of the components of the e2g split band, originally a doubly degenerate mode (8a, 8b) in neat benzene, and the band at 1514 cm−1 is assigned to the 19a mode, an inactive mode in neat benzene. These facts indicate a lowering of symmetry in adsorbed benzene, which may be caused by a strong interaction between S‐TiO2 and the benzene molecule with formation of a benzene to Ti (IV) charge transfer (CT) complex or by the formation of a benzene radical cation species. However, the RR spectra of the adsorbed benzene cannot be assigned to the benzene radical cation because the observed wavenumber of the ring‐breathing mode does not have the value expected for this species. Moreover, it was found by ESR measurements that the amount of radicals was very low, and so it was concluded that a CT complex is the species that originates the RR spectra. The most favorable intensification of the band at 1595 cm−1 in the RR spectra of benzene/S‐TiO2 at higher excitation energy corroborates this hypothesis, as an absorption band in this energy range, assigned to a CT transition, is observed. Copyright © 2008 John Wiley & Sons, Ltd.
Aperture based Raman spectroscopy on SiGe film structures with high spatial resolution
Authors: Mai A. , Zhu L. , Hecker M. , Rinderknecht J. , Georgi C. , Ritz Y. , Zschech E.
Published: January 2008

We have investigated silicon–germanium (SiGe) line structures employing metallic apertures in combination with Raman spectroscopy to obtain high‐spatial strain resolution below the diffraction limit. The apertures were cut into specifically shaped electrochemically etched tungsten tips, which were adjusted within the Raman laser beam on the sample surface by a tuning fork atomic force microscope. With this setup, line structures on patterned SiGe films with a center‐to‐center distance down to 200 nm were resolved in the Raman scans, evidently indicating a resolution clearly below the far‐field Raman resolution of about 600 nm for the used instrument. This setup allows improved local strain analysis by Raman spectroscopy and shows potential for further near‐field Raman applications. Copyright © 2008 John Wiley & Sons, Ltd.
Silver‐bacterial cellulosic sponges as active SERS substrates
Authors: Marques Paula A. A. P. , Nogueira Helena I. S. , Pinto Ricardo J. B. , Neto Carlos Pascoal , Trindade Tito
Published: January 2008

Synthetic Ag‐bacterial cellulose nanocomposites are reported here and their performance as surface enhanced Raman scattering (SERS) substrates was investigated using thiosalicylic acid and 2,2′‐dithiodipyridine as analytes. These nanocomposite materials act as natural sponges when immersed in aqueous or ethanolic solutions allowing capture and SERS detection of certain dissolved molecules. The detection limits for the above organic analytes reached concentrations as low as 10−4 mol·dm−3 and are considerably lower than the conventional vegetable cellulose analogs. Furthermore, we anticipate that the use of these nanocomposites has a beneficial consequence for the development of handy and active cellulosic SERS substrates, in particular for bioanalysis, as we experimentally demonstrated by testing the amino acids L‐phenylalanine, L‐glutamin and L‐histidine. Copyright © 2008 John Wiley & Sons, Ltd.
A Raman spectroscopic and combined analytical approach to the restoration of severely damaged frescoes: the Palomino project
Authors: Edwards Howell G. M. , Doménech‐Carbó M. Teresa , Hargreaves Michael D. , Doménech‐ Carbó Antonio
Published: January 2008

The deterioration of art objects is normally relatively minor, controllable and attributable to environmental changes or bacterial invasion, and until now there has not been any recorded attempt to analyse an artwork that has been deliberately and significantly destroyed. The analytical problems are correspondingly larger but the potential reward from any information that can be forthcoming is thereby proportionately greater. The 17th Century Palomino frescoes on the vaulted ceiling of the Church of Sant Joan del Mercat in Valencia were largely destroyed by insurgents in the Spanish Civil War in 1936. The ensuing gunfire and a series of seven conflagrations inside the church had a devastating effect upon the artwork, and the surviving areas were also rendered unstable with respect to their detachment from the substrate. During the current restoration project being undertaken on these frescoes, an opportunity was provided for the application of several analytical techniques to secure information about the original pigment palette employed, the technology of application used by Palomino and the changes consequent upon the destruction process. Here, we report for the first time the use of analytical Raman spectroscopy, supported by scanning electron microscopy (SEM) and voltammetry of microparticles, for the combined identification of pigments, binders, substrate treatments and pigment alteration in an important, although badly damaged, wall painting for the informing of the ongoing conservation and restoration strategy. Copyright © 2008 John Wiley & Sons, Ltd.
Raman spectral detection and assessment of thin organic layers on metal substrates: systematic approach from substrate preparation to map evaluation
Authors: Člupek Martin , Prokopec Vadym , Matějka Pavel , Volka Karel
Published: January 2008

Raman spectral mapping of thin organic layers on metal substrates is an important analytical tool to characterize these systems. Surface‐enhanced Raman scattering (SERS) spectroscopy is a suitable technique for analysis of such layers. Development of new SERS‐active surfaces with repeatable properties and without disturbing adsorbed species is one of the important steps for reliable assessment of the thin organic layers designed. This paper presents new SERS‐active substrates suitable for both macro (millimeter scale) and microscopic (micrometer scale) spectral mapping, which allow easy regeneration for repetitive experiments. Both gold and silver SERS‐active surfaces prepared by electrochemical deposition were tested. Complete map data evaluation utilities were newly designed and applied, using both ordinarily used and newly modified mathematical algorithms and chemometric procedures. Evaluation of data starts with finite impulse response (FIR) filtration algorithms to eliminate spectral interferences in individual spectra. Principal component analysis was used for transformation of multidimensional data to understandable dimensions. Various mathematical/statistical techniques were then used for data visualization as spectral maps and for similarity testing. Copyright © 2008 John Wiley & Sons, Ltd.
Hemagglutinating activity and corresponding putative sequence identity from Curcuma aromatica rhizome
Authors: Tiptara Ponpimol , Petsom Amorn , Roengsumran Sophon , Sangvanich Polkit
Published: January 2008

BACKGROUND: Curcuma aromatica is a medicinal plant belonging to the Zingiberaceae family with an incomplete genome sequence. It has been reported that extract from the rhizome of this plant contains haemagglutinating activity. In this study the profile of fractions containing hemagglutinating activity is described.

RESULTS: Following extraction with saline buffer, the protein solution was fractionated by ammonium sulfate precipitation. Ion‐exchange chromatography was completed on fast‐flow SP‐Sepharose, as well as gel filtration chromatography on Superdex 75. The active fractions were then separated by one‐dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis and labeled proteins were digested with trypsin. The digest bands were analyzed by reversed‐phase liquid chromatography—tandem mass spectrometry. Inferred peptide sequences were used in Mascot searching and mass spectrometry‐driven BLAST (MS‐BLAST) homology searches allowed the recognition of related proteins in other species of Viridiplantae. Six putative proteins from nine bands showed similarity with lectin sequences.

CONCLUSION: This study reports the identification of six lectins from the Curcuma aromatica rhizome achieved by mass spectrometry using MS‐BLAST algorithms to search for homology between de novo determined peptide sequences and protein sequences available in sequence databases. Copyright © 2008 Society of Chemical Industry
The application of inductively coupled plasma mass spectrometry in clinical pharmacological oncology research
Authors: Brouwers Elke E.M. , Tibben Matthijs , Rosing H. , Schellens Jan H.M. , Beijnen Jos H.
Published: January 2008

Metal‐based anticancer agents are frequently used in the treatment of a wide variety of cancer types. The monitoring of these anticancer agents in biological samples is important to understand their pharmacokinetics, pharmacodynamics, and metabolism. In addition, determination of metals originating from anticancer agents is relevant to assess occupational exposure of health care personnel working with these drugs. The high sensitivity of inductively coupled plasma mass spectrometry (ICP‐MS) has resulted in an increased popularity of this technique for the analysis of metal‐based anticancer drugs. In addition to the quantitative analysis of the metal of interest in a sample, ICP‐MS can be used as an ultrasensitive metal selective detector in combination with speciation techniques such as liquid chromatography. In the current review we provide a systematic survey of publications describing the analysis of platinum‐ and ruthenium‐containing anticancer agents using ICP‐MS, focused on the determination of total metal concentrations and on the speciation of metal compounds in biological fluids, DNA‐ and protein‐adducts, and environmental samples. We conclude that ICP‐MS is a powerful tool for the quantitative analysis of metal‐based anticancer agents from multiple sample sources. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 27:67–100, 2008
Sodium imaging optimization under specific absorption rate constraint
Authors: Stobbe Robert , Beaulieu Christian
Published: January 2008

The concept of sodium imaging RF pulse parameter optimization for signal‐to‐noise ratio (SNR) under specific absorption rate (SAR) constraints is introduced. This optimization concept is unique to sodium imaging, as sodium exhibits ultrarapid T2 relaxation in vivo, and involves minimizing echo time (TE). For 3D radial k‐space acquisition, minimizing TE (and T2 loss) requires minimizing the RF pulse length. SNR optimization also involves exploiting rapid T1 relaxation with shortened repetition time (TR) values. However, especially at higher fields, both RF pulse length and TR are constrained by SAR, which is also dependent on the flip angle. Quantum mechanical simulations were performed for SAR equivalent sets of RF pulse length, TR, and flip angle. It was determined that an SNR advantage is associated with a spoiled steady‐state approach to sodium imaging with radial acquisition even though significantly longer RF pulses (and TE) are required to implement this approach under the SAR constraint at 4.7T. This advantage, compared to RF pulse sequences implementing ultrashort echo times, 90° flip angles, and longer repetition times, was confirmed in healthy volunteers (measured SNR increase of ≈38%) and used to produce excellent quality sodium images of the human brain. Magn Reson Med 59:345–355, 2008. © 2008 Wiley‐Liss, Inc.
Ventricular shape biomarkers for Alzheimer's disease in clinical MR images
Authors: Ferrarini Luca , Palm Walter M. , Olofsen Hans , van der Landen Roald , van Buchem Mark A. , Reiber Johan H.C. , Admiraal‐Behloul Faiza
Published: January 2008

The aim of this work was to identify ventricular shape‐based biomarkers in MR images to discriminate between patients with Alzheimer's disease (AD) and healthy elderly. Clinical MR images were collected for 58 patients and 28 age‐matched healthy controls. After normalizing all the images the ventricular cerebrospinal fluid was semiautomatically extracted for each subject and an innovative technique for fully automatic shape modeling was applied to generate comparable meshes of all ventricles. The search for potential biomarkers was carried out with repeated permutation tests: results highlighted well‐defined areas of the ventricular surface being discriminating features for AD: the left inferior medial temporal horn, the right medial temporal horn (superior and inferior), and the areas close to the left anterior part of the corpus callosum and the head of the right caudate nucleus. The biomarkers were then used as features to build an intelligent machine for AD detection: a Support Vector Machine was trained on AD and healthy subjects and subsequently tested with leave‐1‐out experiments and validation tests on previously unseen cases. The results showed a sensitivity of 76% for AD, with an overall accuracy of 84%, proving that suitable biomarkers for AD can be detected in clinical MR images. Magn Reson Med 59:260–267, 2008. © 2008 Wiley‐Liss, Inc.
Characterization of the dynamic shear properties of hyaline cartilage using high‐frequency dynamic MR elastography
Authors: Lopez Orlando , Amrami Kimberly K. , Manduca Armando , Ehman Richard L.
Published: January 2008

This work evaluated the feasibility of dynamic MR Elastography (MRE) to quantify structural changes in bovine hyaline cartilage induced by selective enzymatic degradation. The ability of the technique to quantify the frequency‐dependent response of normal cartilage to shear in the kilohertz range was also explored. Bovine cartilage plugs of 8 mm in diameter were used for this study. The shear stiffness (μs) of each cartilage plug was measured before and after 16 hr of enzymatic treatments by dynamic MRE at 5000 Hz of shear excitation. Collagenase and trypsin were used to selectively affect the collagen and proteoglycans contents of the matrix. Additionally, normal cartilage plugs were tested by dynamic MRE at shear‐excitations of 3000–7000 Hz. Measured μs of cartilage plugs showed a significant decrease (−37%, P < 0.05) after collagenase treatment and a significant decrease (−28%, P < 0.05) after trypsin treatment. Furthermore, a near‐linear increase (R2 = 0.9141) in the speed of shear wave propagation with shear‐excitation frequency was observed in cartilage, indicating that wave speed is dominated by viscoelastic effects. These experiments suggest that dynamic MRE can provide a sensitive quantitative tool to characterize the degradation process and viscoelastic behavior of cartilage. Magn Reson Med 59:356–364, 2008. © 2008 Wiley‐Liss, Inc.
Comparison of reconstruction accuracy and efficiency among autocalibrating data‐driven parallel imaging methods
Authors: Brau Anja C.S. , Beatty Philip J. , Skare Stefan , Bammer Roland
Published: January 2008

The class of autocalibrating “data‐driven” parallel imaging (PI) methods has gained attention in recent years due to its ability to achieve high quality reconstructions even under challenging imaging conditions. The aim of this work was to perform a formal comparative study of various data‐driven reconstruction techniques to evaluate their relative merits for certain imaging applications. A total of five different reconstruction methods are presented within a consistent theoretical framework and experimentally compared in terms of the specific measures of reconstruction accuracy and efficiency using one‐dimensional (1D)‐accelerated Cartesian datasets. It is shown that by treating the reconstruction process as two discrete phases, a calibration phase and a synthesis phase, the reconstruction pathway can be tailored to exploit the computational advantages available in certain data domains. A new “split‐domain” reconstruction method is presented that performs the calibration phase in k‐space (kx, ky) and the synthesis phase in a hybrid (x, ky) space, enabling highly accurate 2D neighborhood reconstructions to be performed more efficiently than previously possible with conventional techniques. This analysis may help guide the selection of PI methods for a given imaging task to achieve high reconstruction accuracy at minimal computational expense. Magn Reson Med 59:382–395, 2008. © 2008 Wiley‐Liss, Inc.
A sensitive PARACEST contrast agent for temperature MRI: Eu3+‐DOTAM‐glycine (Gly)‐phenylalanine (Phe)
Authors: Li Alex X. , Wojciechowski Filip , Suchy Mojmir , Jones Craig K. , Hudson Robert H.E. , Menon Ravi S. , Bartha Robert
Published: January 2008

Tissue temperature is a fundamental physiological parameter that can provide insight into pathological processes. The purpose of this study was to develop and characterize a novel paramagnetic chemical exchange saturation transfer (CEST) agent suitable for in vivo temperature mapping at 9.4T. The CEST properties of the europium (Eu3+) complex of the DOTAM‐Glycine (Gly)‐Phenylalanine (Phe) ligand were studied in vitro at 9.4T as a function of temperature, pH, and agent concentration. The transfer of magnetization (CEST effect) from the bound water to bulk water pools was ∼75% greater for Eu3+‐DOTAM‐Gly‐Phe compared to Eu3+‐DOTAM‐Gly at physiologic temperature (38°C) and pH (7.0 pH units) when using power level sufficiently low for in vivo imaging. Unlike Eu3+‐DOTAM‐Gly, whose CEST effect decreased with increasing temperature in the physiologic range, the CEST effect of Eu3+‐DOTAM‐Gly‐Phe was optimal at body temperature. A strong linear dependence of the chemical shift of the bound water pool on temperature was observed (0.3 ppm/°C), which was insensitive to pH and agent concentration. Temperature maps with SDs < 1°C were acquired at 9.4T in phantoms containing: 1) phantom A, an aqueous solution of 10 mM Eu3+‐DOTAM‐Gly‐Phe; 2) phantom B, 5% bovine serum albumin (BSA) with 15 mM Eu3+‐DOTAM‐Gly‐Phe; and 3) phantom C, mouse brain tissue with 4 mM Eu3+‐DOTAM‐Gly‐Phe. The temperature sensitivity combined with the high CEST effect observed at low concentration using low saturation power (B1) suggests this compound may be a good choice for in vivo temperature mapping at 9.4T. Magn Reson Med 59:374–381, 2008. © 2008 Wiley‐Liss, Inc.
An evaluation of an aggression management training program to cope with workplace violence in the healthcare sector
Authors: Oostrom Janneke K. , van Mierlo Heleen
Published: January 2008

Workplace violence is a major occupational hazard for healthcare workers, generating a need for effective intervention programs. The purpose of this study was to evaluate the effectiveness of an aggression management training program. The evaluation design was based on the internal referencing strategy, an unobtrusive and applicable evaluation method that rules out some major threats to internal validity without the need for a control group. On three occasions, training participants completed a questionnaire containing experimental and control variables. As hypothesized, there was a significant improvement in the experimental variables that was larger than the non‐significant change in the control variable. We conclude that aggression management training may be an effective instrument in the fight against workplace violence. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:320–328, 2008
Predicting sexual risk behaviors among adolescent and young women using a prospective diary method
Authors: Morrison‐Beedy Dianne , Carey Michael P. , Feng Changyong , Tu Xin M.
Published: January 2008

We describe the sexual risk behaviors, psychological distress, and substance use of 102 late adolescent girls and identify predictors of protected and unprotected vaginal sex. Participants completed questionnaires assessing hypothesized predictors and then daily behavioral diaries for 12 weeks. Protected intercourse was predicted by baseline sexual behavior, greater knowledge, positive condom attitudes, lower perceived condom‐use difficulty, greater condom‐use intentions, more drinking days, less binge drinking, less Ecstasy use, and lower psychological distress. Unprotected intercourse was predicted by baseline sexual behavior, binge drinking, Ecstasy and opiate use, fewer drinking days, and fewer daily drinks. These findings suggest that psychological distress, substance use, and sexual risk behavior are interconnected and should be considered collectively in interventions for adolescent females. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:329–340, 2008
The role of nursing unit culture in shaping research utilization behaviors
Authors: Scott Shannon D. , Pollock Carolee
Published: January 2008

We conducted a focused ethnography of a pediatric critical care unit to examine the role of nursing unit culture related to research utilization. Four significant aspects of the unit culture shaped nurses' research utilization. A hierarchical structure of authority, routinized and technology‐driven work at the bedside, a workplace ethos that discouraged innovation, and an emphasis on clinical experience acted together to teach nurses both that they were to do as they were told and that they were not expected to use research. Nurses perceived that the behaviors expected of them were arbitrarily determined by physicians and managers in charge. Consequently, they were reluctant to step outside of routine and physician‐ordered nursing care. This left little opportunity for research utilization. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:298–309, 2008
Analyzing participant produced photographs from an ethnographic study of fatherhood and smoking
Authors: Oliffe J.L. , Bottorff J.L. , Kelly M. , Halpin M.
Published: January 2008

As part of an ongoing ethnographic study, we examined the photographs and narratives that new fathers produced to ascertain how they created social, psychological, and relational space for continued smoking. A four‐part process for analyzing the photographs consisting of preview, review, cross‐photo comparison, and theorizing revealed how visual data analyses can be used to develop insights into men's health behaviors and beliefs. There is ongoing epistemological debate and methodological uncertainty about how photographic data should be treated in health sciences research. By conducting formal layered analyses, researchers can expand and extend both what is said about, and interpreted through, photographs. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:529–539, 2008
The relationship between pain and functional disability in Black and White older adults
Authors: Horgas Ann L. , Yoon Saunjoo L. , Nichols Austin Lee , Marsiske Michael
Published: January 2008

In this study we examined pain and disability in 115 community‐dwelling, urban, older adults (mean age = 74 years; 52% Black, 48% White). Participants completed a survey of pain (pain presence, intensity, locations, and duration) and disability (Sickness Impact Profile). Sixty percent of the sample reported pain; Black and White adults did not differ on any pain variable. In structural equation models controlling for socioeconomic factors and health, pain did not mediate the relationship between race and disability. Race moderated the pain–disability relationship; pain was more associated with disability among Whites than Blacks. This study highlights the need for greater understanding of health disparities between Black and White older adults as they relate to pain and disability. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:341–354, 2008
Fiscal institutions of Brazilian municipal borrowing
Authors: Martell Christine R.
Published: January 2008

In an effort to understand subnational borrowing, this article explores how three Brazilian institutions—the 1988 Constitution which mandates revenue and expenditure assignments among the levels of the federation; the national Law of Fiscal Responsibility, which imposes expenditure and debt limitations on all levels and branches of government; and various borrowing arrangements—affect the municipal borrowing environment. These institutions are examined in light of de Mello's (2001) policy recommendations for strengthening efficiency and fiscal discipline in subnational borrowing. The institutions of Brazilian borrowing were found to have some of de Mello's recommendations, with the new Constitution and the Law of Fiscal Responsibility making progress towards increased fiscal responsibility, but the current borrowing arrangements serving to maintain a controlled system that is not conducive to responsible municipal borrowing. Several recommendations are made to improve the borrowing environment and foster fiscal discipline and efficiency Copyright © 2008 John Wiley & Sons, Ltd.
Political accountability, fiscal conditions and local government performance—cross‐sectional evidence from Indonesia
Authors: Eckardt Sebastian
Published: January 2008

Why are some local governments more successful than others in managing resources and delivering services? And even more vitally, how can malfunctioning governments be reformed so that they perform their responsibilities more effectively? This article contributes to our understanding of theses overarching questions by exploring the interactions between political institutions and public sector performance in the context of decentralisation and local governance. It shows–both theoretically and empirically–that performance outcomes are determined by the extent to which people can hold their governments accountable through political institutions. The basic hypothesis underlying this research is that political accountability, either by encouraging sanctions upon non‐compliant public agents or simply by reducing the informational gap regarding government activities, will create forceful incentives for elected officials and civil servants to reduce opportunistic behaviour and improve performance. Using a cross‐sectional regression the hypothesis is empirically tested against evidence from newly empowered local governments in Indonesia. The empirical findings broadly support our hypotheses. Improved public services on the ground, both in terms of quantity and quality, require informed and well functioning decision‐making processes that allocate resources to priority areas that meet the demand of the broader community. Copyright © 2008 John Wiley & Sons, Ltd.
Teacher knowledge of and confidence in meeting the needs of children with chronic medical conditions: Pediatric psychology's contribution to education
Authors: Nabors Laura A. , Little Steven G. , Akin‐Little Angeleque , Iobst Emily A.
Published: January 2008

More children and adolescents who have chronic illnesses are being included in regular education classrooms today than ever before. However, teachers may not feel confident about being able to meet these children's educational, social, or emotional needs in the classroom. School psychologists are able to assess children's functioning in these areas and can provide information to teachers on a case‐by‐case basis to ensure that children with chronic illnesses receive appropriate and comprehensive services at school and are included in regular education settings to the fullest extent possible. This study assessed special education and regular education teachers' perceptions of their knowledge about and confidence in meeting the academic and social needs of children with chronic medical conditions. Two‐hundred and forty‐seven teachers from 15 midwestern elementary schools completed a survey rating their knowledge and confidence in meeting the academic and social needs of children with 13 chronic medical conditions. Special education teachers reported being more knowledgeable than regular education teachers about cerebral palsy, epilepsy, hemophilia, spina bifida, renal failure, and allergies. However, overall, special education teachers were not more confident than regular education teachers in meeting the academic needs of children with chronic medical conditions. Future research should focus on whether experience affects teacher knowledge and confidence and should examine the effectiveness of interventions to improve teacher knowledge for working with children with medical conditions. © 2008 Wiley Periodicals, Inc.
Psychology's contributions to classroom management
Authors: Little Steven G. , Akin‐Little Angeleque
Published: January 2008

Classroom management (CRM) has been associated with discipline, control, or other terms that connote reducing unacceptable student behavior. However, CRM involves not merely responding effectively when problems occur, but also preventing problems from occurring by creating environments that encourage learning and appropriate behavior. Teachers' managerial abilities have been found to positively relate to students' behavior and achievement in every process‐product study to date. Researchers have consistently identified the components necessary for effective CRM. However, no one has surveyed working teachers to ascertain the extent to which teachers use the research findings in their classrooms. A survey was developed in order to attempt to answer this question. The survey consisted of three sections asking questions on demographics, classroom rules, and classroom child management. One hundred and forty‐six teachers from U.S. school districts in the Midwest, South, and Southwest were surveyed. Results indicated that, overall, teachers reported the use of appropriate CRM procedures in relatively high frequencies. However, the high percentage of districts reporting the use of corporal punishment was disturbing given the research findings regarding its lack of effectiveness. Along with the presentation of the survey results, this article also discusses how the data on CRM, collected by psychologists, has contributed to improvements in teacher behavior and student achievement and the apparent gap between best practice and actual practice. © 2008 Wiley Periodicals, Inc.
Psychology and education, together again
Authors: Rosenfield Sylvia
Published: January 2008

The relationship between psychology and education has waxed and waned over the past century. In addition, a core issue for psychologists is how to bridge the gap between theory and practice in applied settings such as schools. While acknowledging the work that has been done, it is apparent that the effective dissemination of psychology to education remains a work in progress and a continuing challenge. © 2008 Wiley Periodicals, Inc.
Mechanism of excitation and relaxation in Er,O‐codoped GaAs for 1.5 μm light‐emitting devices with extremely stable wavelength
Authors: Fujiwara Yasufumi , Takemoto Shouichi , Tokuno Takehiro , Hidaka Keiji , Ichida Hideki , Suzuki Masato , Terai Yoshikazu , Kanematsu Yasuo , Tonouchi Masayoshi
Published: January 2008

Energy‐transfer processes in Er,O‐codoped GaAs (GaAs:Er,O) have been investigated by means of a pump and probe reflection technique. Time‐resolved reflectivity exhibited a characteristic dip; a negative signal due to bandgap renormalization in less than 1 ps and then a gradual recovery. In the recovery process, there were two components, fast and slow. The fast recovery time (several ps) was inversely proportional to Er concentration. The analysis based on a rate equation indicated that it is due to the capture of electrons by charged traps. The slow recovery (30–60 ps) was well coincident with the time (54 ps) predicted theoretically in the framework of a multiphonon‐assisted model. Optical excitation cross section of Er ions in GaAs:Er,O has also been studied in various samples and shown to depend strongly on Er concentration. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of process conditions on gain and loss in GaN:Eu cavities on different substrates
Authors: Park J. H. , Steckl A. J.
Published: January 2008

GaN:Eu laser cavities have been fabricated by MBE growth on several substrates. Gain and loss from Eu stimulated emission have been investigated as a function of several process parameters: Eu concentration, post‐growth anneal and substrate (sapphire, silicon and glass). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Demonstration of ErSiO superlattice crystal waveguide toward optical amplifiers and emitters
Authors: Isshiki H. , Ushiyama T. , Kimura T.
Published: January 2008

ErSiO superlattice crystal (SC) waveguide is demonstrated. ErSiO‐SC film was formed on a SiO2/Si substrate. After the ErSiO preform formation by sol–gel method, high temperature anneal for the crystallization was performed in Ar atmosphere. Then the ErSiO‐SC layer thickness is 220 nm. Then refractive index of ErSiO‐SC was estimated to be 1.8 by ellipsometry and reflection spectroscopy measurements. To obtain the lateral optical confinement, polymer cladding layer (n = 1.54) was coated on the ErSiO‐SC film and the strip‐loaded structures with 5 μm width were formed by focused ion beam (FIB) etching. The optical confinement factor Γ of the ErSiO‐SC waveguide layer was estimated to be 0.42, assuming the lateral confinement factor was 1 because of the sufficient wide waveguide for the light. Optical pumping was performed by using a 1480 nm laser diode through the lensed fiber. The pumping power is 30 mW at the fiber input. Green light emissions corresponding to 4f intra‐shell transitions from 4S3/2 and 2H11/2 to 4I15/2 in the Er3+ ions, indicating cooperative upconversion in the ErSiO‐SC waveguide, can be observed by using a conventional CCD system at room temperature. The upconversion emission behaviour through the waveguide with a photon trap for the 1480 nm light reveals that the 1480 nm pumping light is well‐confined into the waveguide. The cooperative upconversion as the gain limitting factor in the ErSiO‐SC waveguide are discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Site‐selective spectroscopy of erbium in wide band gap semiconductors
Authors: Kozanecki A. , Glukhanyuk V. , Przybylińska H.
Published: January 2008

In this paper results of site‐selective spectroscopy of Er3+ ions in wide band gap semiconductors, such as cubic and hexagonal GaN, and 6H SiC are presented. Photoluminescence excitation (PLE) spectroscopy was applied to find the Stark splitting pattern of energy levels in the 4I9/2 manifolds. It is shown that in cubic and hexagonal GaN only one center dominates. In the case of wurtzite GaN it is most probably due to Er occupying a Ga site, whereas in the cubic phase point‐charge model calculations suggest a slightly distorted, Td interstitial site. In 6H SiC three different centers were distinguished. The energy level schemes for the 4I9/2 and the ground 4I15/2 states were determined for all three centers, basing on the results of photoluminescence and PLE measurements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards p‐type ZnO using post‐growth annealing
Authors: Dangbegnon J. K. , Roro K. T. , Botha J. R.
Published: January 2008

The optical properties of zinc oxide (ZnO) films grown by metalorganic chemical vapor deposition on GaAs substrate are investigated. Samples were annealed in two different ambients, namely nitrogen and oxygen, and studied by photoluminescence (PL). Samples annealed in oxygen at 600 °C show arsenic acceptor‐related signatures. The near‐band‐edge emission is dominated by an excitonic feature at 3.355 eV and compensation broadens the spectra. No such changes are observed when similar samples are annealed in nitrogen. The diffusion of arsenic from the GaAs substrate appears to be a source of acceptors. This effect is enhanced in an oxygen atmosphere. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The development of room temperature LEDs and lasers for the mid‐infrared spectral range
Authors: Krier A. , Yin M. , Smirnov V. , Batty P. , Carrington P. J. , Solovev V. , Sherstnev V.
Published: January 2008

There are many applications for mid‐infrared light sources which has stimulated intensive research into the physics and technology of narrow gap materials and devices. In this article we give an overview of the development of mid‐infrared LEDs and diode lasers being studied in our laboratory. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of ZnO as a perspective material for photonics
Authors: Khranovskyy V. , Yazdi G. R. , Lashkarev G. , Ulyashin A. , Yakimova R.
Published: January 2008

Emissive properties of ZnO are of great interests in terms of the UV LED device design. The persistent “green” luminescence due to deep defect is an obstacle for obtaining an intense UV emission, expected from ZnO. We report the positive role of thermally diffused H toward quenching the defect emission in ZnO. It is suggested that hydrogen passivates defects responsible for DLE, resulting in efficient near band edge luminescence. As‐grown ZnO/SiNx:H/Si films, deposited at 350 °C demonstrate intense narrow peaks of UV emission at 380 nm and a ratio of emission intensities, NBE/DLE ≈ 42. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cu2Zn1–xCdx Sn(Se1–ySy)4 solid solutions as absorber materials for solar cells
Authors: Altosaar M. , Raudoja J. , Timmo K. , Danilson M. , Grossberg M. , Krustok J. , Mellikov E.
Published: January 2008

Cu2Zn1–x Cdx Sn(Se1–y Sy)4 monograin powders with different x ‐ and y ‐values were prepared from binary compounds in the liquid phase of flux material (KI) in evacuated quartz ampoules. All the materials had uniform composition and p‐type conductivity. PL spectra (10 K) of the as grown Cu2Zn1–x Cdx Sn(Se)4 monograin powders showed one PL band with peak position around 0.85 eV which shifted linearly to the lower energy side with increasing Cd content. Cu2ZnSnS4 material showed asymmetrical PL band at 1.31 eV attributed to band‐to‐tail recombination. RT Raman spectra of Cu2ZnSnSe4 revealed two main peaks at 196 cm–1 and 173 cm–1 and a third less intensive peak with varying peak position in the region 231–253 cm–1. Raman spectra of Cu2ZnSnS4 showed an intensive peak at 338 cm–1 and additional peaks at 287 cm–1 and 368 cm–1. Narrow sieved fractions of grown powders were used as absorber materials in monograin layer (MGL) solar cell structures: graphite/ Cu2Zn1–x Cdx Sn(Se1–y Sy)4/CdS/ZnO. The best so far solar cell that was based on the Cu2Zn0.8Cd0.2SnSe4 had open circuit voltage 422 mV, short circuit current 12 mA/cm2 and fill factor 44%. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Annealing experiments of the GaP based dilute nitride Ga(NAsP)
Authors: Kunert B. , Trusheim D. , Voßebürger V. , Volz K. , Stolz W.
Published: January 2008

The post‐growth annealing behaviour of Ga(NAsP) multi quantum well heterostructures (MQWHs) grown pseudomorphically strained to GaP substrate has been investigated. The optical properties as well as the structural crystal quality of the novel dilute nitride show an obvious dependence on the applied annealing temperature. Photoluminescence (PL) measurements reveal a step‐like blue shift of the PL peak position in line with an increase of PL intensity with rising annealing temperature. The PL line width decreases to a mini‐ mal value for an optimized heating temperature around 800 °C. This annealing behaviour of the Ga(NAsP)/GaP‐MQWHs up to 850 °C is quite typical for a dilute nitride, however, the functional dependence of the integrated intensity above 850 °C is unusual. The increase of the PL line width above 850 °C suggests a deterioration of the crystalline MQW quality, but transmission electron microscopy (TEM) and high resolution X‐ray diffraction (XRD) prove the opposite. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the electric field on the current instability in the hopping conductivity region
Authors: Aladashvili D. I. , Adamia Z. A. , Adamia A. Z.
Published: January 2008

The dependence of the shape of current oscillations observed in the hopping conductivity region in a weakly compensated p‐Si on the supply voltage applied to the sample is established. With increasing bias voltage the current pulse shape to form a hopping domain changes significantly. The change in the shape is ascribed to voltage redistribution in corresponding regions in the bulk of the crystal. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ion channels allow atomic control of macroscopic transport
Authors: Eisenberg Bob
Published: January 2008

Ion channels are proteins with a hole down their middle that control an enormous range of biological function. Thousands of biologists and clinicians study ion channels every day because of their crucial involvement in disease. Ion channels have a definite structure once open and ions move through them by electrodiffusion. Theories that describe the movement of charged spheres through definite structure are able to account for the experimental behavior of channels in a wide range of conditions with just a few parameters with fixed values. Selectivity is produced by the balance of electrostatic attraction and hard sphere repulsion in at least three types of channels. More ‘chemical’ forces are not involved. The free energy landscapes of these systems are variables. Preformed binding sites are not involved. Indeed, in some cases selectivity is produced by depletion zones, not binding sites. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theory of hopping charge‐carrier transport at large carrier concentrations in disordered organic solids: Polarons versus bare charge carriers
Authors: Fishchuk I. I. , Kadashchuk A. , Bässler H.
Published: January 2008

An analytical theory based on the effective medium approach with employing the concept of the effective transport energy is formulated to describe the charge carrier mobility as a function of the charge carrier concentration in a disordered organic material with a Gaussian density‐of‐state distribution. Jump rate expressions based either on the Miller‐Abrahams (MA) or polaron models are used. A key result of the present study is that a considerably weaker dependence of the mobility on the carrier concentration is found for the polaron jump rate model than for the MA model where we have considerable increase of the drift charge‐carrier mobility with increasing carrier concentration. Our results for the MA model are in good agreement with previous theoretical studies, numerical simulation and experiment data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Metallic conductivity in a polyamidine film
Authors: Ionov A. N. , Rentzsch R. , Nikolaeva M. N.
Published: January 2008

Experimental results are discussed which deal with metallic conductivity in partially conjugated and undoped polyamidine thin films placed between metallic electrodes. In the framework of a model, the electrification effect due to metallic electrodes plays the significant role in obtaining metallic conductivity. The main reason for metallic conductivity in dielectric polyamidine films is the collapse of the HOMO/ LUMO gap of macromolecules (here HOMO – is the highest occupied molecular orbital and LUMO – is the lowest unoccupied molecular orbital) in a strong internal electrical field inside the polymer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
One‐dimensional lucky‐drift model with scattering and movement asymmetries for impact ionization in amorphous semiconductors
Authors: Jandieri K. , Rubel O. , Baranovskii S. D. , Reznik A. , Rowlands J. A. , Kasap S. O.
Published: January 2008

A lucky‐drift (LD) model for impact ionization has been recently successfully used to account for avalanche phenomenon in amorphous semiconductors. This model however leads to the dependence of the impact ionization coefficient on the sample thickness. However such dependence has not been confirmed experimentally. Recently LD model has been improved taking into account the scattering and movement asymmetry of charge carriers in the applied electric field. As a result, the impact ionization coefficient was obtained independent on the sample thickness. We apply the improved LD model to study the field dependence of the impact ionization coefficient in a‐Se, a‐Si:H and Ge2Sb2Te5. We show that even in one‐dimensional formulation of the improved LD model the agreement between theoretical results and experimental data evidenced in a‐Se is better than that in the formulation with scattering and movement symmetry. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Particle on a ring coupled with a dirty metal
Authors: Kagalovsky Victor , Horovitz Baruch
Published: January 2008

A charged particle of mass M on a ring of radius R is coupled to a dirty metal environment. With Monte‐Carlo methods we evaluate the curvature of the Aharonov‐Bohm oscillations and find a quantum phase transition at a critical Rc. At low temperatures T the curvature has the form 1/M*R2 with an R independent M* > M in the R > Rc phase, while M* rapidly approaches M in the R < Rc phase. The approach to T = 0 defines diverging length scales ∼T–η with η ≈ 1 and η ≈ 1/4 in the large and small R phases, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)