bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stable isotope constraints on the origin of the Cabo de Creus garnet‐tourmaline pegmatites, Massif des Alberes, Eastern Pyrenees, Spain
Authors: Damm Klaus‐Werner , Harmon Russell S. , Heppner Peter‐Michael , Dornsiepen Ulrich 
Published: February 2007

AbstractPegmatite dyke swarms are exposed within the easternmost Pyrenees at Cabo de Creus. These dykes were emplaced into high‐grade metamorphosed sedimentary strata of Cambro‐Ordovician age, but lack obvious field relationship to Hercynian intrusive rocks. Together with structural and geochemical data, equilibrium oxygen isotope fractionations at temperatures of ≈ 600°C, the lack of obvious subsolidus exchange, and the H‐ and O‐isotopic signatures of water in equilibrium with pegmatite mica and quartz are interpreted to indicate a derivation from anatexis of a metapelitic source at shallow crustal levels.
Biostratigraphy of Dinantian limestones and associated volcanic rocks in the Limerick Syncline, Ireland
Authors: Somerville Ian D. , Strogen Peter , Jones Gareth Li. 
Published: February 2007

AbstractRocks of Courceyan to Brigantian age are exposed in the Limerick Syncline. However, a complete Courceyan succession is known only from two boreholes which correlate closely, both faunally and lithologically, with a standard Limerick Province succession in the Pallaskenry Borehole on the Shannon estuary. This is followed by a thick Waulsortian sequence (the newly defined Limerick Limestone Formation) of late Courceyan to early Chadian age and overlying cherty micrites (the newly defined Lough Gur Formation) of early to late Chadian age, whose top is younger to the east. The Lough Gur Formation is succeeded by lavas and tuffs of the Knockroe Volcanic Formation whose upper part is interbedded with and overlain by shallow water oolites and algal‐rich bioclastic limestones of the Herbertstown Limestone Formation. The higher part of the latter is in turn interbedded with lavas and tuffs of the Knockseefin Volcanic Formation. The Herbertstown Limestone has rich and diverse coral/brachiopod and foraminiferal assemblages of late Chadian to Asbian age. Its base is markedly diachronous: late Chadian in the west of the syncline and Holkerian in the east. Both the base and top of the Knockroe Volcanic Formation are thus shown to be markedly diachronous and volcanism extends from the Chadian to early Asbian. The Knockseefin Volcanic Formation is entirely of Asbian age. The highest limestones (Dromkeen Limestone Formation) have a diagnostic late Asbian–early Brigantian fauna and are overstepped by mid‐Namurian shales.
Nautiloid cephalopods of the Kildare Limestone (Ashgill), Ireland
Authors: Holland C. H. 
Published: February 2007

AbstractThe nautiloid cephalopod fauna of the Kildare Limestone (Ordovician, Ashgill), County Kildare, eastern Ireland is described as a whole for the first time. It consists of four orthoconic taxa, newly assigned taxonomically, and one coiled form. There are other orthocones, doubtfully determined or undetermined.
Source of the Bicester magnetic anomaly
Authors: Kearey P. , Rabae A. M. 
Published: February 2007

AbstractThe Bicester magnetic anomaly is one of several high wavenumber features superimposed on the magnetic anomaly associated with the London Platform. Seismic reflection data suggest that the source of the Bicester anomaly is a body of basaltic rocks of Carboniferous age that can be traced from the Steeple Aston borehole. Three‐dimensional interpretational techniques indicate that the magnetic source has a total magnetization vector dipping at 60°, azimuth 170°, with an intensity of 1.39 A m−1 and this has been used to derive a three‐dimensional model of the source. The nature of the magnetic remanence contributing to this vector is discussed. A detailed two‐dimensional magnetic model has been constructed using the seismic control.
Pre‐Middle Silurian granitic magmatism and associated metamorphism in northern Japan: SHRIMP U‐Pb zircon chronology
Authors: Watanabe Teruo , Fanning C. Mark , Uruno Katsutoshi , Kano Hiroshi 
Published: February 2007

AbstractThe results of SHRIMP U‐Pb zircon dating are presented for igneous and metamorphic rocks of enigmatic age in northern Japan. The SHRIMP analyses for the Tsubonosawa metamorphic rocks included in the Hikami Granite reveals (1) Ordovician sedimentation of the original rocks, including Archaean‐Proterozoic detrital zircons, and (2) thermal metamorphism with partial melting or assimilation followed by intrusion of the Hikami Granite at ca. 440 Ma (end of Ordovician). This study allows the reconstruction of Siluro‐Ordovician palaeogeography and magmatism‐associated metamorphism in East Asia. The SHRIMP results are compared with those of CHIME (chemical U‐Pb total Th isochron method) chronology, which is evaluated as providing significant reconnaissance ages in some instances.
Dental health, nutritional status and recent‐onset dementia in a Korean community population
Authors: Kim Jae‐Min , Stewart Robert , Prince Martin , Kim Sung‐Wan , Yang Su‐Jin , Shin Il‐Seon , Yoon Jin‐Sang 
Published: February 2007

AbstractBackgroundDental health is an important determinant of nutritional status, but has not been investigated as a risk factor for dementia. This study aimed to investigate the association between number of teeth, use of dentures and recent‐onset dementia.MethodsThis was a cross‐sectional analysis nested within a prospective study of community dwelling elderly residents in two areas of Kwangju, South Korea. In a study of 686 community residents aged 65 or over without dementia followed over 2.4 years, measures of dental health were compared between those with and without dementia at follow‐up.ResultsFewer teeth were significantly associated with dementia and Alzheimer's disease. This association was strongest in participants without dentures. Strong associations were found between fewer teeth and indices of poor nutrition in this group, but these did not account for the association with dementia.ConclusionsHaving fewer teeth may be a marker of risk for dementia. This might be explained by specific nutritional deficits, or by other side effects of periodontal disease. Further prospective research is indicated. Copyright © 2007 John Wiley & Sons, Ltd.
Parieto‐occipital sources account for the increase in alpha activity with working memory load
Authors: Tuladhar Anil M. , Huurne Niels ter , Schoffelen Jan‐Mathijs , Maris Eric , Oostenveld Robert , Jensen Ole 
Published: February 2007

AbstractThe role of oscillatory alpha activity (8–13 Hz) in cognitive processing remains an open question. It has been debated whether alpha activity plays a direct role in the neuronal processing required for a given task or whether it reflects idling and/or functional inhibition. Recent electroencephalography (EEG) studies have demonstrated that alpha activity increases parametrically with load during retention in working memory paradigms. While it is known that the parieto‐occipital cortex is involved in the generation of the spontaneous alpha oscillations, it remains unknown where the sources of the memory‐dependent alpha activity are located. We recorded brain activity using magnetoencephalography (MEG) from human subjects performing a Sternberg memory task where faces were used as stimuli. Spectral analysis revealed a parametric increase in alpha activity with memory load over posterior brain areas. We then applied a source reconstruction technique that allowed us to map the parametric increase in alpha activity to the anatomical magnetic resonance (MR) images of the subject. The primary sources of the memory‐dependent alpha activity were in the vicinity of the parieto‐occipital sulcus. This region is not directly involved in working memory maintenance of faces. Our findings are consistent with the notion that alpha activity reflects disengagement or inhibition of the visual dorsal stream. We propose that the disengagement reflected in alpha power serves to suppress visual input in order to devote resources to structures responsible for working memory maintenance. Hum Brain Mapp 2007. © 2007 Wiley‐Liss, Inc.
The bootstrap and cross‐validation in neuroimaging applications: Estimation of the distribution of extrema of random fields for single volume tests, with an application to ADC maps
Authors: Viviani Roberto , Beschoner Petra , Jaeckle Tina , Hipp Peter , Kassubek Jan , Schmitz Bernd 
Published: February 2007

AbstractWe discuss the assessment of signal change in single magnetic resonance images (MRI) based on quantifying significant departure from a reference distribution estimated from a large sample of normal subjects. The parametric approach is to build a test based on the expected distribution of extrema in random fields. However, in conditions where the variance is not uniform across the volume and the smoothness of the images is moderate to low, this test may be rather conservative. Furthermore, parametric tests are limited to datasets for which distributional assumptions hold. This paper investigates resampling methods that improve statistical tests for signal changes in single images in such adverse conditions, and that can be used for the assessment of images taken for clinical purposes. Two methods, the bootstrap and cross‐validation, are compared. It is shown that the bootstrap may fail to provide a good estimate of the distribution of extrema of parametric maps. In contrast, calibration of the significance threshold by means of cross‐validation (or related sampling without replacement techniques) address three issues at once: improved power, better voxel‐by‐voxel estimate of variance by local pooling, and adaptation to departures from ideal distributional assumptions on the signal. We apply the cross‐validated tests to apparent diffusion coefficient maps, a type of MRI capable of detecting changes in the microstructural organization of brain parenchyma. We show that deviations from parametric assumptions are strong enough to cast doubt on the correctness of parametric tests for these images. As case studies, we present parametric maps of lesions in patients suffering from stroke and glioblastoma at different stages of evolution. Hum Brain Mapp 2007. © 2007 Wiley‐Liss, Inc.
Neural mechanisms of evoked oscillations: Stability and interaction with transient events
Authors: Moratti Stephan , Clementz Brett A. , Gao Yuan , Ortiz Tomás , Keil Andreas 
Published: February 2007

AbstractThere is increasing evidence that early event‐related potentials are a result of phase alignment of ongoing background oscillations of the electroencephalogram rather than additive amplitude modulation. Steady state visual‐evoked potentials (ssVEPs) can be recorded using an intensity modulated stimulus, resulting in an evoked brain response at a known frequency, i.e. the stimulation frequency. Given this property, the ssVEP is ideally suited for examining the relationship between single‐trial fluctuations in phase/amplitude and the evoked brain potential resulting from averaging across trials. To address this issue, the current study investigated the contribution of single trial power and intertrial phase locking to ssVEP generation by presenting a peripheral flicker. Further, transient stimuli were presented during flicker and at three increasing latency lags following flicker offset to examine (1) to what extent a stimulus can disturb the ssVEP oscillation and (2) how phase alignment during P1‐N1‐P2 time windows is affected during presence of evoked oscillations. The former assessment evaluates the stability of ssVEPs and the latter the phase alignment processes to transient stimuli under experimentally induced background oscillations. We observed that ssVEPs are a result of phase alignment rather than single trial amplitude modulation. In addition, ssVEP oscillations were not disturbed by transient stimuli. Finally, phase alignment in P1‐N1‐P2 time windows was distorted during and shortly after steady state stimulation. We conclude that ssVEPs represent strongly phase locked oscillations sharing the same generation mechanisms as early evoked potentials. Hum Brain Mapp, 2007. © 2007 Wiley‐Liss, Inc.
Bias between MNI and Talairach coordinates analyzed using the ICBM‐152 brain template
Authors: Lancaster Jack L. , Tordesillas‐Gutiérrez Diana , Martinez Michael , Salinas Felipe , Evans Alan , Zilles Karl , Mazziotta John C. , Fox Peter T. 
Published: February 2007

AbstractMNI coordinates determined using SPM2 and FSL/FLIRTwith the ICBM‐152 template were compared to Talairach coordinates determined using a landmark‐based Talairach registration method (TAL). Analysis revealed a clear‐cut bias in reference frames (origin, orientation) and scaling (brain size). Accordingly, ICBM‐152 fitted brains were consistently larger, oriented more nose down, and translated slightly down relative to TAL fitted brains. Whole brain analysis of MNI/Talairach coordinate disparity revealed an ellipsoidal pattern with disparity ranging from zero at a point deep within the left hemisphere to greater than 1‐cm for some anterior brain areas. MNI/Talairach coordinate disparity was generally less for brains fitted using FSL. The mni2tal transform generally reduced MNI/Talairach coordinate disparity for inferior brain areas but increased disparity for anterior, posterior, and superior areas. Coordinate disparity patterns differed for brain templates (MNI‐305, ICBM‐152) using the same fitting method (FSL/FLIRT) and for different fitting methods (SPM2, FSL/FLIRT) using the same template (ICBM‐152). An MNI‐to‐Talairach (MTT) transform to correct for bias between MNI and Talairach coordinates was formulated using a best‐fit analysis in one hundred high‐resolution 3‐D MR brain images. MTT transforms optimized for SPM2 and FSL were shown to reduced group mean MNI/Talairach coordinate disparity from a 5‐13 mm to 1‐2 mm for both deep and superficial brain sites. MTT transforms provide a validated means to convert MNI coordinates to Talairach compatible coordinates for studies using either SPM2 or FSL/FLIRTwith the ICBM‐152 template. Hum Brain Mapp 2007. © 2007 Wiley‐Liss, Inc.
Phase lag index: Assessment of functional connectivity from multi channel EEG and MEG with diminished bias from common sources
Authors: Stam Cornelis J. , Nolte Guido , Daffertshofer Andreas 
Published: February 2007

AbstractObjective:To address the problem of volume conduction and active reference electrodes in the assessment of functional connectivity, we propose a novel measure to quantify phase synchronization, the phase lag index (PLI), and compare its performance to the well‐known phase coherence (PC), and to the imaginary component of coherency (IC).Methods:The PLI is a measure of the asymmetry of the distribution of phase differences between two signals. The performance of PLI, PC, and IC was examined in (i) a model of 64 globally coupled oscillators, (ii) an EEG with an absence seizure, (iii) an EEG data set of 15 Alzheimer patients and 13 control subjects, and (iv) two MEG data sets.Results:PLI and PC were more sensitive than IC to increasing levels of true synchronization in the model. PC and IC were influenced stronger than PLI by spurious correlations because of common sources. All measures detected changes in synchronization during the absence seizure. In contrast to PC, PLI and IC were barely changed by the choice of different montages. PLI and IC were superior to PC in detecting changes in beta band connectivity in AD patients. Finally, PLI and IC revealed a different spatial pattern of functional connectivity in MEG data than PC.Conclusion:The PLI performed at least as well as the PC in detecting true changes in synchronization in model and real data but, at the same token and like‐wise the IC, it was much less affected by the influence of common sources and active reference electrodes. Hum Brain Mapp 2007. © 2007 Wiley‐Liss, Inc.
Estimating the number of independent components for functional magnetic resonance imaging data
Authors: Li Yi‐Ou , Adalı Tülay , Calhoun Vince D. 
Published: February 2007

AbstractMultivariate analysis methods such as independent component analysis (ICA) have been applied to the analysis of functional magnetic resonance imaging (fMRI) data to study brain function. Because of the high dimensionality and high noise level of the fMRI data, order selection, i.e., estimation of the number of informative components, is critical to reduce over/underfitting in such methods. Dependence among fMRI data samples in the spatial and temporal domain limits the usefulness of the practical formulations of information‐theoretic criteria (ITC) for order selection, since they are based on likelihood of independent and identically distributed (i.i.d.) data samples. To address this issue, we propose a subsampling scheme to obtain a set of effectively i.i.d. samples from the dependent data samples and apply the ITC formulas to the effectively i.i.d. sample set for order selection. We apply the proposed method on the simulated data and show that it significantly improves the accuracy of order selection from dependent data. We also perform order selection on fMRI data from a visuomotor task and show that the proposed method alleviates the over‐estimation on the number of brain sources due to the intrinsic smoothness and the smooth preprocessing of fMRI data. We use the software package ICASSO (Himberg et al. [ 2004]: Neuroimage 22:1214–1222) to analyze the independent component (IC) estimates at different orders and show that, when ICA is performed at overestimated orders, the stability of the IC estimates decreases and the estimation of task related brain activations show degradation. Hum Brain Mapp, 2007. © 2007 Wiley‐Liss, Inc.
An empirical investigation of the social market for cigarettes
Authors: Katzman Brett , Markowitz Sara , McGeary Kerry Anne 
Published: February 2007

AbstractA major characteristic of teenage smoking is the ability to ‘bum’ cigarettes from peers. To date, research into the determinants of teenage smoking has largely ignored the effects of this social market on the smoking decisions of teenagers. In this paper, we estimate the demand for cigarettes using data from the Youth Risk Behavior Survey which distinguishes teens who primarily buy cigarettes from those who primarily borrow cigarettes. Our results demonstrate the ways in which higher cigarette prices and restrictions on smoking influence not only a teen's decision to smoke and the quantity of cigarettes smoked, but also the manner in which cigarettes are acquired. We show that current cigarette regulations are ineffective in reaching the group of light smokers who primarily obtain cigarettes through the social market, thus indicating that alternative measures should be explored in an effort to reduce the number of smokers in the future. Copyright © 2007 John Wiley & Sons, Ltd.
Salivary glutathione and uric acid levels in patients with head and neck squamous cell carcinoma
Authors: Almadori Giovanni , Bussu Francesco , Galli Jacopo , Limongelli Attilio , Persichilli Silvia , Zappacosta Bruno , Minucci Angelo , Paludetti Gaetano , Giardina Bruno 
Published: February 2007

AbstractBackground.We evaluated the concentrations of glutathione and uric acid, low molecular weight antioxidants, in saliva of patients with head and neck squamous cell carcinoma (HNSCC), in order to identify differences with normal subjects and to obtain information about biochemical alterations of human saliva during carcinogenesis.Methods.We compared 50 HNSCC patients, divided in 2 subsets on the basis of tumor site, with a control group of 77 subjects, without a previous diagnosis of HNSCC, matched for age, sex, alcohol consumption, and smoking status.Results.At tests for equality of means by Welch and Brown‐Forsythe, differences between groups resulted probable for salivary levels of glutathione (p = .004 and p < .001 respectively) but not for salivary levels of uric acid (p = .228 and p = .122 respectively). Comparing groups by Tamhane test, the patients with oral or pharyngeal cancer had significantly higher salivary levels of glutathione than both controls and patients with laryngeal cancer.Conclusions.Salivary glutathione levels may be an index of oxidative stress at the level of the upper airways and in particular of oral cavity and pharynx. Therefore, high salivary glutathione may be an epidemiological marker to identify subjects with an increased risk of developing HNSCC, to submit to strict follow‐up and chemoprevention. Metabolic alterations of saliva could be both an epidemiological marker and a target for chemoprevention of oral and oropharyngeal carcinogenesis. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Swallowing after major surgery of the oral cavity or oropharynx: A prospective and longitudinal assessment of patients treated by microvascular soft tissue reconstruction
Authors: Borggreven Pepijn A. , Leeuw Irma Verdonck‐de , Rinkel Rico N. , Langendijk Johannes A. , Roos Jan C. , David Eric F. L. , de Bree Remco , Leemans C. René 
Published: February 2007

AbstractBackground.The aim of this study was to analyze swallowing outcome in advanced oral/oropharyngeal cancer patients treated with microvascular reconstructive surgery and adjuvant radiotherapy.Methods.Eighty patients were included. Patient, tumor, and treatment factors were assessed. Postoperative videofluoroscopic swallowing studies (VFSS) and scintigraphy tests were performed at 6 (n = 54 vs 44) and 12 (n = 32 vs 37) months. Swallowing parameters such as the oropharyngeal swallow efficiency and the Penetration/Aspiration Scale were analyzed.Results.Impaired swallowing status was found at 6 months, which remained stationary at 12 months. Comorbid condition, larger tumors (T3‐T4 vs T2), and resections of the base of tongue and soft palate combined (vs defects of other dynamic structures) were associated with most profound swallowing problems (p < .05).Conclusions.Swallowing difficulties are relatively frequent and can to a large extent be predicted. With the knowledge of this study, better counseling and vigilance as to swallowing difficulties may be possible. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Lifetime physical activity and the risk of renal cell cancer
Authors: Tavani Alessandra , Zucchetto Antonella , Maso Luigino Dal , Montella Maurizio , Ramazzotti Valerio , Talamini Renato , Franceschi Silvia , La Vecchia Carlo 
Published: February 2007

AbstractThe relation between lifelong physical activity at work and during leisure‐time and the risk of renal cell cancer (RCC) was analyzed in a case‐control study conducted in Italy between 1992 and 2004. Cases were 767 subjects with incident, histologically confirmed RCC, and controls were 1,534 patients hospitalized for acute nonneoplastic conditions. Odds ratios (OR) and 95% confidence intervals (CI) for RCC were computed by multiple logistic regression models, conditioned on study center, sex and age, and adjusted for main covariates. Compared to the lowest level of occupational physical activity, the multivariate OR of RCC for the highest level were 0.65 (95% CI 0.49–0.87) at age 12 years, 0.67 (95% CI 0.53–0.84) at age 15–19, 0.74 (95% CI 0.59–0.93) at age 30–39 and 0.71 (95% CI 0.55–0.92) at age 50–59 years, with significant inverse trends in risk. The inverse association was consistent in strata of sex, age at diagnosis, body mass index, smoking habit and alcohol drinking. No significant association was found for leisure‐time physical activity. The inverse association between occupational physical activity and RCC risk, if real, may be related to the effects of insulin‐like growth factors, or lipid peroxidation and about 9% of cases of RCC in Italy could be avoided by increasing physical activity. However the inverse association might involve confounding by indirect mechanisms, such as body composition or other social class correlates. © 2006 Wiley‐Liss, Inc.