bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of large basis set DFT and MP2 calculations in the study of the barrier for internal rotation of 2,3,5,6‐tetrafluoroanisole
Authors: Kieninger Martina , Cachau Raúl E. , Oberhammer Heinz , Ventura Oscar N. 
Published: September 2006

AbstractThe barrier for internal rotation around the OCH3 bond in 2,3,5,6‐tetrafluoroanisole was calculated using the density functional theory (DFT) and second‐order Møller–Plesset (MP2) methods with Pople's basis sets up to 6‐311++G(3df,2p) and Jensen basis sets up to pc‐3. The results are converged only if fairly large basis sets are used (at least 6‐311++G(3df,2pd) or pc‐2). Both the DFT and MP2 potential energy curves show internal structure. Two minima and three maxima are observed on the curves, arising from the interplay between lone‐pair delocalization and changes in the hybridization around the oxygen atom, together with the attraction between the positively polarized hydrogens in the methyl group and the negatively polarized fluorine atom at the ortho position. These critical points are somehow ironed out by the addition of zero‐point and thermal corrections to the energy curves. At this level, the MP2 method can describe reasonably well the previously determined single‐well experimental rotational barrier, 2.7 ± 2.0 kcal/mol at 298 K, while all DFT methods yield a much smaller result. As observed experimentally, the OCH3 group is perpendicular to the aryl ring in the equilibrium structure, although two very close minima with an intermediate hump at 90° are still observable. The theoretical free energy barrier of rotation at the MP2(full)/pc‐2 level is 2.0 ± 1.0 kcal/mol, in reasonable agreement with the experimental determination. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Density functional and ab initio studies on structures and energies of the ground state of CrCO
Authors: Kim Joonghan , Lee Yoon Sup , Ihee Hyotcherl 
Published: September 2006

AbstractCrCO was studied using density functional theory (DFT) and ab initio methods. We obtained the two‐dimensional potential energy surface (PES), geometry, and vibrational frequencies for CrCO in a septet state. Two minimum structures were found in the CCSD(T) calculation, including a local minimum that is a weak van der Waals (vdW) complex. All DFT methods yield only one minimum structure. We demonstrate that the bond dissociation energy (0.50 kcal/mol) and vibrational frequency (1981.1 cm−1) of CrCO calculated using CCSD(T) are in better agreement with experimental values (<1.5 kcal/mol and 1977 cm−1) than any of the reported theoretical studies. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Comparison of transition probabilities calculated using different parameters on WBEPM theory for some p‐d and d‐p transitions in excited atomic nitrogen
Authors: Çelik Gültekin , Akin Erhan , Kiliç Hamdi Şükür 
Published: September 2006

AbstractThe transition probabilities between individual and multiplet lines for some quartet terms of excited p‐d and d‐p transition arrays of nitrogen atom have been calculated using the weakest bound electron potential model (WBEPM) theory. For determination relevant parameters, we employed both numerical Coulomb approximation (NCA) method and numerical nonrelativistic Hartree–Fock (NRHF) wave functions for expectation values of radii. The necessary energy values have been taken from experimental energy data in the literature. The expectation values of radii obtained using the two different methods have been employed in the calculation of transition probabilities of all transition arrays. The results obtained have been compared with either each other or NIST data. Good agreement with accepted values taken from NIST has been observed for related excited transitions. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Random changepoint modelling of HIV immunologic responses
Authors: Ghosh Pulak , Vaida Florin 
Published: September 2006

AbstractWe propose a changepoint model for the analysis of longitudinal CD4 T‐cell counts for HIV infected subjects following highly active antiretroviral treatment. The profile of CD4 counts for each subject follows a simple, ‘broken stick’ changepoint model, with random subject‐specific parameters, including the changepoint. The model accounts for baseline covariates. The longitudinal CD4 records are censored at the time of the subject going off‐study‐treatment. This is a potentially informative drop‐out mechanism, which we address by modelling it jointly with the CD4 count outcome. The drop‐out model incorporates terms from the CD4 model, including the changepoint. The estimation is done in a Bayesian framework, with implementation via Markov chain Monte Carlo methods in the WinBUGS software. Model selection using DIC indicates that the data support the complex random changepoint and informative censoring model. Copyright © 2006 John Wiley & Sons, Ltd.
Optimal designs for estimating the most successful dose
Authors: Zohar Sarah , O'Quigley John 
Published: September 2006

AbstractThere has been much recent interest in phase I/II dose finding designs in which information on both toxicity and efficacy is used. Unlike the classic phase I dose finding design in which the aim is to identify the MTD (maximum tolerated dose corresponding to some percentile of acceptable toxicity), a phase I/II dose finding study aims to locate the most successful dose (MSD), i.e. the dose which maximizes the product of the probability of seeing no toxicity together with the probability of seeing a therapeutic response). In this work we present an abstract theoretical design for this purpose. We call this design a ‘virtual’ design. The virtual design, conceptually similar to that developed for phase I designs alone, is based on a bivariate response. The design has optimal properties in that the current estimates of both probability of toxicity and those for response achieve the Cramer–Rao bound for every dose level. Unhappily, the virtual design is not available for practical use but its use can be exploited in theoretical investigations in much the same way as one uses the Cramer–Rao bound for unbiased estimators, i.e. a tool which enables us to see how much room for improvement may exist for any given real design. Via examples taken from the literature on phase I/II dose finding we illustrate how this technique can provide us with further insight on the relative performance of competing designs. Copyright © 2006 John Wiley & Sons, Ltd.
Correction for regression dilution bias using replicates from subjects with extreme first measurements
Authors: Berglund Lars , Garmo Hans , Lindbäck Johan , Zethelius Björn 
Published: September 2006

AbstractThe least squares estimator of the slope in a simple linear regression model will be biased towards zero when the predictor is measured with random error, i.e. intra‐individual variation or technical measurement error. A correction factor can be estimated from a reliability study where one replicate is available on a subset of subjects from the main study. Previous work in this field has assumed that the reliability study constitutes a random subsample from the main study.We propose that a more efficient design is to collect replicates for subjects with extreme values on their first measurement. A variance formula for this estimator of the correction factor is presented. The variance for the corrected estimated regression coefficient for the extreme selection technique is also derived and compared with random subsampling. Results show that variances for corrected regression coefficients can be markedly reduced with extreme selection. The variance gain can be estimated from the main study data. The results are illustrated using Monte Carlo simulations and an application on the relation between insulin sensitivity and fasting insulin using data from the population‐based ULSAM study.In conclusion, an investigator faced with the planning of a reliability study may wish to consider an extreme selection design in order to improve precision at a given number of subjects or alternatively decrease the number of subjects at a given precision. Copyright © 2006 John Wiley & Sons, Ltd.
Balancing vertical integration and strategic outsourcing: effects on product portfolio, product success, and firm performance
Authors: Rothaermel Frank T. , Hitt Michael A. , Jobe Lloyd A. 
Published: September 2006

AbstractMost prior research has focused on vertical integration or strategic outsourcing in isolation to examine their effects on important performance outcomes. In contrast, we focus on the simultaneous pursuit of vertical integration and strategic outsourcing. Our baseline proposition is that balancing vertical integration and strategic outsourcing in the pursuit of taper integration enriches a firm's product portfolio and product success, and in turn contributes to competitive advantage and thus to overall firm performance. We derive a set of detailed hypotheses, and test them on a unique and fine‐grained panel of longitudinal data documenting over 3,500 product introductions in the global microcomputer industry. The results provide strong support for the notion that carefully balancing vertical integration and strategic outsourcing when organizing for innovation helps firms to achieve superior performance. Copyright © 2006 John Wiley & Sons, Ltd.
CEO incentives, innovation, and performance in technology‐intensive firms: a reconciliation of outcome and behavior‐based incentive schemes
Authors: Makri Marianna , Lane Peter J. , Gomez‐Mejia Luis R. 
Published: September 2006

AbstractBuilding on the agency view of corporate governance, we propose that technology‐intensive firms use both outcome and behavior‐based performance criteria for rewarding CEOs. Using a sample of 206 firms from 12 U.S. manufacturing industries, we find that as technological intensity increases CEO bonuses are more closely linked to financial results and that total CEO incentives are associated with two indicators of desirable innovation behaviors: invention resonance and science harvesting. Invention resonance refers to the impact a firm's inventions have on other firms' inventions, while science harvesting reflects a firm's commitment to scientific research. As technological intensity increases, aligning bonus with financial results, total incentives with invention resonance, and total incentives with science harvesting predict firm market performance. Copyright © 2006 John Wiley & Sons, Ltd.
The licensing dilemma: understanding the determinants of the rate of technology licensing
Authors: Fosfuri Andrea 
Published: September 2006

AbstractThe licensing of technology entails a trade‐off: licensing payments net of transaction costs (revenue effect) must be balanced against the lower price–cost margin and/or reduced market share implied by increased competition (profit dissipation effect) from the licensee. We argue that the presence of multiple technology holders, which compete in the market for technology, changes such a trade‐off and triggers more aggressive licensing behavior. To test our theory, we analyze technology licensing by large chemical firms during the period 1986–96 for 107 chemical products. We find that the rate of technology licensing displays an inverted U‐shaped relationship with the number of potential technology suppliers and is negatively related to the licensor's market share and to the degree of technology‐specific product differentiation. Copyright © 2006 John Wiley & Sons, Ltd.
Spreadsheets, Service Providers, and the Statehouse: Using Data and the Wraparound Process to Reform Systems for Children and Families
Authors: Bruns Eric J. , Rast Jim , Peterson Christa , Walker Janet , Bosworth Jone 
Published: September 2006

AbstractEvaluation descriptions in the research literature tend to ignore the full context of the community change efforts from which they emerged. In this paper, we describe a range of evaluation studies and data collection activities conducted over the course of one state's effort to reform its child welfare system on behalf of families with children experiencing serious mental health problems. Initial activities included studies of the prevalence of unmet mental health need in children and youth in the state. As these needs were addressed, evaluation activities examined the impact of a pilot wraparound program that became a major part of systems reform. Later efforts included implementation analysis of wraparound programs and assessment of priorities for continued systems reform. As we describe this set of evaluation activities, we discuss how data collection evolved to meet the needs of stakeholders over time and consider lessons learned about the roles of research and information sharing in shaping community change efforts.
Necessary Conditions for Mean Square Convergence of the Best Linear Factor Predictor
Authors: Krijnen Wim P. 
Published: September 2006

AbstractSeveral sufficient conditions are available for mean square convergence of factor predictors. A necessary and sufficient condition is given in the Heywood case with respect to (confirmatory) factor analysis. This condition generalizes that of Krijnen (2006) and performs better than a signal-to-noise type of condition (Schneeweiss & Mathes, 1995).
Effect of testosterone on ex vivo vascular reactivity in man
Authors: Malkin Christopher J. , Jones Richard D. , Jones T. Hugh , Channer Kevin S. 
Published: September 2006

Testosterone is reported to have an acute vasodilating action in vitro, an effect that may impart a favourable haemodynamic response in patients with chronic heart failure. However, the effect of chronic testosterone exposure on general vascular reactivity is poorly described. In the present study, fresh subcutaneous resistance arteries were obtained from patients with heart failure (n=10), healthy controls (n=9) and men with androgen-deficiency (n=17). All arteries were studied using a wire myograph to examine the effect of cumulative additions of testosterone (1 nmol/l–100 μmol/l) compared with vehicle control following maximal pre-constriction with KCl (1–100 μmol/l). The vascular reactivity of arteries from androgen-deficient patients was examined further by recording tension concentration curves to cumulative additions of noradrenaline (1 nmol/l–100 μmol/l) and U46619 (1–300 nmol/l), followed by relaxation concentration curves to additions of ACh (acetylcholine; 10 nmol/l–30 μmol/l) and SNP (sodium nitroprusside; 10 nmol–30 μmol/l) respectively. In all cases, statistical analysis was performed by ANOVA. Patients with proven androgen-deficiency were treated according to clinical recommendations for a minimum of 3 months and further arteries (n=19) were taken for experimentation using the same protocol. In all groups, testosterone was confirmed to be an acute concentration-dependent vasodilator at concentrations ≥1 μmol/l (P=0.0001). The dilating effect of testosterone was augmented in patients with androgen-deficiency prior to treatment, and this effect was abrogated following appropriate testosterone replacement. Testosterone therapy significantly reduced the normal vascular dilating response to ACh and SNP (P&lt;0.01) and significantly increased the contractile response to noradrenaline (P&lt;0.01), but not U46619. Testosterone is an acute dose-dependent vasodilator of resistance arteries. Physiological testosterone replacement attenuates general vascular reactivity in androgen-deficient subjects. The numerous perceived benefits of testosterone replacement may be offset by a decline in vascular reactivity and, therefore, further studies and careful monitoring of patients is recommended.
Development of the Client‐Centred Care Questionnaire
Authors: De Witte Luc , Schoot Tineke , Proot Ireen 
Published: September 2006

Aim.  This paper reports the development and testing of the Client‐Centred Care Questionnaire, aimed at evaluating the client‐centredness of professional home nursing care from a client perspective.Background.  Client‐centred care has become an important theme in health care. To evaluate the client‐centredness of care and services from a client's perspective, there is a need for measurement instruments.Method.  The questionnaire was developed on the basis of a qualitative study into client perspectives on home nursing care. Items were formulated that closely followed the aspects clients mentioned as central to client‐centred home care. A pilot study was conducted with a sample of 107 clients in three home care organizations in 2003 and 2004. These clients had chronic diseases and were expected to receive care for at least another 6 months. The questionnaire comprises 15 items.Findings.  Principal components analysis and internal consistency analysis show strong internal consistency of the items. All items had strong factor loadings on one dimension, and Cronbach's alpha was 0·94. Clients tended to be most critical about their say in the practical arrangements and organization of care: which person came, how often and when? Clients of the three organizations differed in their perceptions of client‐centredness, which may indicate that the questionnaire is capable of differentiating between respondents.Conclusion.  The results of this pilot study are promising. The validity of the questionnaire needs further testing.
Human biogeography: evidence of our place in nature
Authors: Terrell John Edward 
Published: September 2006

AbstractFocusing on human biogeography as a research endeavour may make sense to biogeographers, but in the academic world generally this particular scholarly niche has long been filled by other rival disciplines such as sociology, human ecology, geography, anthropology and archaeology. It may be true that having so many ways of looking at ourselves as a species is a good thing, but it can also be argued that this academic fragmentation of effort has often nurtured the commonplace view that we as a species are ‘above’ or ‘not part of’ what plain folks call the ‘natural world’. Here I review the historical and basic intellectual ingredients of what might be (but often isn't) called human biogeography. I offer a case study drawn from my research work on the Sepik coast of Papua New Guinea. This research illustrates how adopting an explicitly biogeographical approach to human diversity can lead to unexpected insights into the character and history of human settlement in this part of the world. One benefit of having a field with this explicit orientation might be that the conservation of biodiversity would make more sense to more people.
Steroid‐free immunosuppression regime reduces both long‐term cardiovascular morbidity and patient mortality in renal transplant recipients
Authors: Sandrini Silvio , Maffeis Roberto , Setti Gisella , Bossini Nicola , Maiorca Paolo , Maffei Camilla , Guerini Simona , Zubani Roberto , Portolani Nazario , Bonardelli Stefano , Nodari Franco , Giulini Stefano Maria , Cancarini Giovanni 
Published: September 2006

Abstract:  The aim of this retrospective study was to assess the impact of steroid therapy on cardiovascular disease (CVD) and patient mortality, in 486 on‐CsA renal transplant recipients, with a follow‐up of 9.5 ± 4.3 yr. Two hundred and one patients had their steroids permanently withdrawn at sixth month after transplantation (G1); 285 patients did not (G2) as they were unable (acute rejection after suspension) or unsuitable (because of clinical criteria or immunosuppressive protocols). The CVD considered were coronary artery disease diagnosed by angiography and myocardial infarction. G1 and G2 patients were well‐matched regarding CVD risk factors, except for age (G1: 44 ± 14 yr; G2: 40 ± 12 yr; p < 0.003), incidence of male (G1: 62%; G2: 72%, p < 0.02) incidence of acute rejection (G1: 39%; G2: 83%, p < 0.0001). Both CVD and deaths occurring during the first year of transplantation were excluded from the analysis. At 20 yr, the cumulative probability of developing a CVD, was 3.8% in G1; 23.8% in G2 (p < 0.0005). Patient survival rate was 95% in G1; 62% in G2 (p < 0.003). Mortality caused by CVD was higher in G2 (4.2% vs. 0.5%; p < 0.03). The Cox analysis identified in steroid therapy the main independent risk factors for both CVD (hazard ratio 9.56 p < 0.0001) and patient mortality (hazard ratio 5.99, p < 0.0001). At 10th and 15th year after transplantation, the mean‐daily dose of steroids was 4.2 mg.In the long‐term, steroid therapy, even in low‐doses, increases significantly both the rate of CVD and patient mortality. This retrospective study suggests that steroid‐free regime should always be recommended for the prevention of post‐transplant CVD. This relevant statement should be followed by a long‐term prospective study.
Supraorbital nerve block in trabeculectomy surgery: an observational case series
Authors: Tay Eugene , Gupta Mohit , Franks Wendy 
Published: September 2006

AbstractThirteen patients completed a visual analogue pain scale after trabeculectomy with topical anaesthesia and a supraorbital nerve block with 2 mL of lignocaine 2%. Ease of surgery was graded on a scale of 0–5. Inadvertent eye movements and episodes of orbicularis spasm were recorded. Statistical analysis was performed using stata software. Median pain score (range) during delivery of anaesthesia was 2 (1–5), during surgery was 0 (0–4) and postoperatively was 0 (0–3). Pain scores after surgery were significantly lower than during delivery of anaesthesia (Wilcoxon signed rank test, P = 0.0289). Three subjects had inadvertent eye movements with ease of surgery recorded as 1 of 5 in 12 cases and 2 of 5 in one case. The novel application of this anaesthetic technique offers adequate analgesia in trabeculectomy surgery. However, a larger scale comparative trial is needed to further evaluate the value of this technique.
Ciliary body medulloepithelioma: clinical, ultrasound biomicroscopic and histopathologic correlation
Authors: Ayres Bernadete , Brasil Oswaldo M , Klejnberg Celso , Moura Letícia R , Fernandes Bruno F , Burnier Miguel N 
Published: September 2006

AbstractA 3‐year‐old girl presented with a distorted pupil and decrease of visual acuity. A ciliary body mass at the superior‐temporal quadrant could be seen at slit‐lamp examination. Ultrasound biomicroscopy revealed a lesion with lobulated surface, arising at the ciliary body, composed of compact and cystic areas. An iridocyclectomy was performed but the tumour recurred after a few months. The eye was then enucleated. Histopathologic evaluation showed sheets and cords of proliferated medullary epithelium. Cystic spaces and Flexner‐Wintersteiner rosettes were also seen. Those findings correlated well with ultrasound biomicroscopic images. The knowledge of echographic characteristics can significantly assist in the diagnosis of medulloepithelioma of the ciliary body.
Presumed eccrine carcinoma metastatic to the choroid
Authors: Moura Letícia R , Ayres Bernadete , Feijóo Luciana , Romano Sérgio , Odashiro Alexandre N , Burnier Miguel N 
Published: September 2006

AbstractThe purpose of this article is to describe a patient with presumed choroidal metastasis from an eccrine adenocarcinoma of the scalp. A 45‐year‐old Caucasian woman presented with decreased visual acuity. Ophthalmologic examination was unremarkable. Her past medical history was significant for eccrine carcinoma of the scalp. The patient developed bilateral cervical lymph node metastases, and received chemotherapy and radiotherapy. She had recurrence of the scalp lesion and developed bone metastasis. The patient was again referred to an ophthalmologist owing to reduced visual acuity. Multiple choroidal metastases were detected in right eye, and one metastatic lesion in left eye. The patient passed away 2 months after choroidal metastases. This is the first report of choroidal metastases from an eccrine carcinoma. This is a rare aggressive neoplasm with poor outcome in most cases of metastatic disease, and in this case report, uveal metastasis was indicative of poor prognosis.