bluuebunny/crossref_metadata_2025_split huggingface dataset:
Channel incision, evolution and potential recovery in the Walla Walla and Tucannon River basins, northwestern USA
Authors: Beechie T. J. , Pollock M. M. , Baker S. 
Published: August 2007

AbstractWe evaluated controls on locations of channel incision, variation in channel evolution pathways and the time required to reconnect incised channels to their historical floodplains in the Walla Walla and Tucannon River basins, northwestern USA. Controls on incision locations are hierarchically nested. A first‐order geological control defines locations of channels prone to incision, and a second‐order control determines which of these channels are incised. Channels prone to incision are reaches with silt‐dominated valley fills, which have sediment source areas dominated by loess deposits and channel slopes less than 0·1(area)−0·45. Among channels prone to incision, channels below a second slope–area threshold (slope = 0·15(area)−0·8) did not incise. Once incised, channels follow two different evolution models. Small, deeply incised channels follow Model I, which is characterized by the absence of a significant widening phase following incision. Widening is limited by accumulation of bank failure deposits at the base of banks, which reduces lateral channel migration. Larger channels follow Model II, in which widening is followed by development of an inset floodplain and aggradation. In contrast to patterns observed elsewhere, we found the widest incised channels upstream of narrower reaches, which reflects a downstream decrease in bed load supply. Based on literature values of floodplain aggradation rates, we estimate recovery times for incised channels (the time required to reconnect to the historical floodplain) between 60 and 275 years. Restoration actions such as allowing modest beaver recolonization can decrease recovery time by 17–33 per cent. Published in 2007 by John Wiley & Sons, Ltd.
Antenna combining for multi‐antenna multi‐relay channels
Authors: Fan Yijia , Adinoyi Abdulkareem , Thompson John S. , Yanikomeroglu Halim 
Published: August 2007

AbstractIn this paper we analyse the performance of multiple relay channels when multiple antennas are deployed only at relays. We apply two antenna diversity techniques at relays, namely maximum ratio combining (MRC) on receive and transmit beamforming (TB). We show that for both decode‐and‐forward and amplify‐and‐forward relaying protocols, with K relays the network can be decomposed into K diversity channels each with a different channel gain, and that the signals can be effectively combined at the destination. We assume that the total number of antennas at all relays is fixed at N. With a reasonable power constraint at the relays, the network capacity will be lower bounded by that of N relay channels each with single antenna, and upper bounded by that of single relay channel with N antennas. Copyright © 2007 John Wiley & Sons, Ltd.
Channel estimation for chip‐level Alamouti coded multi‐rate CDMA: blind subspace algorithms and performance analysis
Authors: Nicolov Eugene B. , Nazar Shahrokh Nayeb , Psaromiligkos Ioannis N. 
Published: August 2007

AbstractIn this work we consider the problem of blind channel estimation for the downlink of a variable spreading gain (VSG) multi‐rate code‐division‐multiple‐access (MR CDMA) system which uses the orthogonal space‐time block coding (STBC) proposed by Alamouti. In contrast to traditional symbol‐level STBC CDMA systems, we consider a chip‐level ST block coding system for which we derive a simple subspace‐based blind channel estimation method. For the derived algorithm we investigate the necessary and sufficient conditions for the channel to be uniquely identifiable up to a complex multiplicative constant. We also analyse the behaviour of the channel estimation algorithm as a function of the data samples utilised, establishing its unbiasedness and providing a closed‐form expression for the mean‐square‐error (MSE) as well as the Cramer—Rao bound (CRB) for the channel estimation performance. Copyright © 2007 John Wiley & Sons, Ltd.
A revision of Palaeontinidae (Insecta: Hemiptera: Cicadomorpha) from the Jurassic of China with descriptions of new taxa and new combinations
Authors: Bo Wang , Haichun Zhang , Yan Fang , Yutao Zhang 
Published: August 2007

AbstractThe new generic name Martynovocossus nom. nov. (Hemiptera, Palaeontinidae) is proposed as a replacement name for the preoccupied and junior homonym Pseudocossus Martynov, 1931, non Pseudocossus Kenrick, 1914, non Pseudocossus Gaede, 1933. The new genus group is redefined based on new, exceptionally preserved material including complete forewings and hindwings with colour pattern preservation. The synonymies for Martynovocossus zemcuznicovi comb. nov., M. turgaiensis comb. nov., M. strenus comb. nov., M. punctulosus comb. nov., M. bellus comb. nov. and M. ancylivenius comb. nov. are established, and the diagnostic characters for M. strenus comb. nov., M. bellus comb. nov. and M. punctulosus comb. nov. are revised. Two new species, M. decorus sp. nov. and M. cheni sp. nov., are described from the Middle Jurassic Daohugou Lagerstätte. Martynovocossus species display considerable intraspecific variation, particularly in aspects of wing size, venation and colour pattern. A key to species of Martynovocossus is presented. Copyright © 2007 John Wiley & Sons, Ltd.
Prevention and cure efforts both substitute and complement
Authors: Hennessy David A. 
Published: August 2007

AbstractSuppose one could expend effort to prevent probabilistic transition to an adverse state, and also effort to expedite probabilistic transition to a beneficial state. Bearing in mind that the efforts occur in different states, should these efforts substitute or complement? Two appealing arguments are in conflict. If cure effort is costly, then the incentive to prevent should be high in order to avoid future cure effort costs, i.e. efforts are gross substitutes in demand. If prevention effort is costly, then the incentive to cure should be low since recidivism is likely, i.e. efforts complement. In a lifetime present value model, we show that both arguments have merit. We also show that the prevalence of the adverse state can rise with a subsidy on cure effort costs. Copyright © 2007 John Wiley & Sons, Ltd.
Open‐label steady‐state pharmacokinetic drug interaction study on co‐administered quetiapine fumarate and divalproex sodium in patients with schizophrenia, schizoaffective disorder, or bipolar disorder
Authors: Winter Helen R. , DeVane C. Lindsay , Figueroa Carlos , Ennis Debra J. , Hamer‐Maansson Jennifer E. , Davis Patty C. , Smith Mark A. 
Published: August 2007

AbstractObjectiveTo determine whether there is a pharmacokinetic drug interaction between quetiapine fumarate and divalproex sodium.MethodsThe pharmacokinetics and short‐term tolerability and safety of coadministered quetiapine and divalproex were examined in adults with schizophrenia/schizoaffective disorder (Cohort A) or bipolar disorder (Cohort B) in an open‐label, parallel, 2‐cohort drug‐interaction study conducted at three centers in the United States. Cohort A was administered quetiapine (150 mg bid) prospectively for 13 days, with divalproex (500 mg bid) added on days 6–13. Cohort B was administered divalproex (500 mg bid) for 16 days, with quetiapine (150 mg bid) added on days 9–16. Quetiapine and valproic acid plasma concentration–time data over a 12‐h steady‐state dosing interval were used to determine Cmax, Tmax, Cmin, area under the plasma concentration–time curve (AUCτ), and oral clearance (CL/F).ResultsIn Cohort A (n = 18), addition of divalproex did increase the Cmax of quetiapine by 17% but did not change AUCτ. In Cohort B (n = 15), addition of quetiapine decreased both total valproic acid Cmax and AUCτ by 11%. No differences were observed in adverse events (AEs) with either quetiapine or divalproex monotherapy or their combination.ConclusionCombination therapy with quetiapine (150 mg bid) and divalproex (500 mg bid) resulted in small and statistically non‐significant pharmacokinetic changes. Copyright © 2007 John Wiley & Sons, Ltd.
A proposed structure–groundwater model: application to chalky media of the Paris Basin
Authors: Lallahem S. , Lamouroux Ch. , Mania J. , Hani A. 
Published: August 2007

AbstractThe groundwater flow in a fissured chalky environment at the northern border of the Paris Basin depends on several geological and hydrogeological parameters. Although the studied sector of the basin presents a homogeneous rock type, it is affected by a fracture network. In this type of environment, in which the permeability is low, the groundwater flow displays significant disruption, which is localized in the Fruges region (northern France). The interconnection of the discontinuities (network of fault and/or joints) is reliant on the structural control of groundwater flow through increases in the hydraulic connection between the unsaturated and the saturated zone. The methodology developed herein makes use of microstructural and regional analysis of the fracture patterns, and allowed consideration of the piezometric variations of the chalk aquifer during periods of low and high groundwater levels (April and October 2001) and a diagraphic representation of the estimated physical parameters (electrical resistivity). This enabled us to construct a ‘flow structure’ conceptual model in which we identify two types of faults: tight walls and flow paths that control the piezometric heads and the flow rate. Model validation was carried out on a similar sector. Copyright © 2007 John Wiley & Sons, Ltd.
Magnetic resonance imaging of vulnerable atherosclerotic plaques: Current imaging strategies and molecular imaging probes
Authors: Briley‐Saebo Karen C. , Mulder Willem J.M. , Mani Venkatesh , Hyafil Fabien , Amirbekian Vardan , Aguinaldo Juan Gilberto S. , Fisher Edward A. , Fayad Zahi A. 
Published: August 2007

AbstractThe vulnerability or destabilization of atherosclerotic plaques has been directly linked to plaque composition. Imaging modalities, such as magnetic resonance (MR) imaging, that allow for evaluation of plaque composition at a cellular and molecular level, could further improve the detection of vulnerable plaque and may allow for monitoring the efficacy of antiatherosclerotic therapies. In this review we focus on MR imaging strategies for the detection and evaluation of atherosclerotic plaques and their composition. We highlight recent advancements in the development of MR pulse sequences, computer image analysis, and the use of commercially available MR contrast agents, such as gadopentic acid (Gd‐DTPA), for plaque characterization. We also discuss molecular imaging strategies that are currently being used to design specific imaging probes targeted to biochemical and cellular markers of atherosclerotic plaque vulnerability. J. Magn. Reson. Imaging 2007;26:460–479. © 2007 Wiley‐Liss, Inc.
Maximizing contrast‐to‐noise ratio in ultra‐high resolution peripheral MR angiography using a blood pool agent and parallel imaging
Authors: Wang Maisie S. , Haynor David R. , Wilson Gregory J. , Leiner Tim , Maki Jeffrey H. 
Published: August 2007

AbstractPurposeTo determine sequence parameters that maximize vascular contrast‐to‐noise (CNR) for ultra‐high resolution equilibrium phase (EP) peripheral imaging for the blood pool agent (BPA) Vasovist.Materials and MethodsA model for maximizing CNR in EP MR angiography (MRA) is presented. Tissue relaxation times, coil geometry (g)‐factors, and clinical imaging requirements (voxel volume and scan time) were determined from human studies. Using these known values, parameters for TR, TE, bandwidth, flip angle (FA), and sensitivity encoding (SENSE) factor that maximized CNR were derived from the model. CNR was enhanced by using reduction in scan time gained from parallel imaging to increase TR and minimize bandwidth. A total of 10 patients were imaged using model‐derived EP CE‐MRA parameters.ResultsThe model closely predicted experimental CNR data measured in two clinical studies (r2 = 0.85) and demonstrated an increase in CNR by a factor of 2.3 when subjects were imaged using optimal sequence parameters (P < 0.001). Thigh and calf data were acquired with voxel volumes on the order of 0.2 mm3 using a SENSE factor of 4.ConclusionRecommended imaging parameters for a 12‐channel and 18‐channel peripheral vascular coil at two doses of Vasovist (0.03 mmol/kg and 0.05 mmol/kg) are presented. J. Magn. Reson. Imaging 2007;26:580–588. © 2007 Wiley‐Liss, Inc.
Numerical simulation of in vitro pulsatile flow and its study using FRISK, a rapid phase contrast technique
Authors: Li Longchuan , Doyle Mark , Rayarao Geetha , Kortright Eduardo , Ito Yasushi , Anayiotos Andreas 
Published: August 2007

AbstractPurposeTo test the potential of a phase contrast magnetic resonance (PC‐MR) sparse sampling technique, fragmented regional interpolation segmentation for k‐space (FRISK), to capture complex flow features within a breathhold duration by using numerical simulations and experimental approaches.Materials and MethodsComputational fluid dynamics (CFD) data of three models were generated: a two‐chamber orifice flow model simulating valvular regurgitation, a femoral artery model, and a U‐shaped model simulating the aortic arch. These data were used to simulate conventional and FRISK PC‐MR data acquisitions. FRISK parameters can be adapted for different flow fields to capture either high temporal information or complexly varying spatial information with a temporal component or a mixture of both. In vivo PC‐MR images on a healthy volunteer were sampled to compare conventional PC‐MR with novel FRISK imaging.ResultsIn our simulations of three representative models, when only the errors from different sampling sequences were considered, FRISK was shown to maintain or even improve data accuracy while cutting the scan time by at least 50% compared to corresponding conventional PC‐MR. By adapting the FRISK parameters for flowfields with different features, FRISK was capable of capturing in‐plane and through‐plane velocity information with excellent detail in approximately 20 heartbeats breathhold duration. The results of the in vivo MR experiment were consistent with the simulation results, showing that breathhold FRISK imaging improved spatial resolution of the data and maintained adequate temporal resolution compared with breathhold conventional imaging.ConclusionFRISK, a new MRI sampling sequence that sparsely samples data and aligns acquired data during postprocessing, provides a scan time advantage of approximately a factor of 2 compared to conventional scans, and allowed rapid or breathhold scanning while obtaining acceptable accuracy. J. Magn. Reson. Imaging 2007;26:805–815. © 2007 Wiley‐Liss, Inc.
The pyramidal tract has a predictable course through the centrum semiovale: A diffusion‐tensor based tractography study
Authors: Yamada Kei , Kizu Osamu , Kubota Takao , Ito Hirotoshi , Matsushima Shigenori , Oouchi Hiroyuki , Nishimura Tsunehiko 
Published: August 2007

AbstractPurposeTo identify reproducible anatomical landmarks that would allow predicting the course of the pyramidal tract (PT) through centrum semiovale.Materials and MethodsA total of 20 normal volunteers (12 males, eight females) with a mean age of 34 years (range, 20–59 years) were scanned using a 1.5‐Tesla clinical MR unit to assess the trajectory of the PT. Neuroanatomical characteristics of the PT passing through the centrum semiovale were assessed by two independent observers. Tractography data of 10 consecutive patients with brain tumor were used to test the precision of anatomy‐based prediction of the tract location.ResultsOn sagittal view, 95% of the PT depicted on tractography displayed a completely straight or primarily straight course through the supratentorial brain. In 98% of tracts, the bending point of the PT was identified ≤3 mm from the level of the anterior commissure‐posterior commissure (AC‐PC) plane. In 80% of PT, the intersection with the AC‐PC plane occurred midway between the AC and the PC as seen on the sagittal view. Evaluation of the PT in 10 patients with brain tumor revealed that the anatomy‐based prediction of PT on the contralesional hemisphere was not substantially deviated from the actual tractography depicted PT. PT on the lesional hemispheres, however, had deviations of various degrees.ConclusionThe course of the PT through supratentorial brain can be predicted based on easily identifiable landmarks. This anatomy‐based prediction can be clinically applied for cases without substantial mass effect from a space occupying lesion. J. Magn. Reson. Imaging 2007;26:519–524. © 2007 Wiley‐Liss, Inc.
Automated analysis of contrast enhancement in breast MRI lesions using mean shift clustering for ROI selection
Authors: Stoutjesdijk Mark J. , Veltman Jeroen , Huisman Henkjan , Karssemeijer Nico , Barentsz Jelle O. , Blickman Johan G. , Boetes Carla 
Published: August 2007

AbstractPurposeTo evaluate a new method for automated determination of a region of interest (ROI) for the analysis of contrast enhancement in breast MRI.Materials and MethodsMean shift multidimensional clustering (MS‐MDC) was employed to divide 92 lesions into several spatially contiguous clusters each, based on multiple enhancement parameters. The ROIs were defined as the clusters with the highest probability of malignancy. The performance of enhancement analysis within these ROIs was estimated using the area under the receiver operator characteristic curve (AUC), and compared against a radiologist's final assessment and a classifier using histogram analysis (HA). For HA, the first, second, and third quartiles were evaluated.ResultsMS‐MDC resulted in AUC = 0.88 with a 95% confidence interval (CI) of 0.81–0.95. The AUC for the radiologist's assessment was 0.93 (95%CI = 0.87–0.97). Best HA performance was found using the first quartile, with AUC = 0.79 (95%CI = 0.69–0.88). There was no significant difference between MS‐MDC and the radiologist (P = 0.40). The improvement of MS‐MDC over HA was significant (P = 0.018).ConclusionMean shift clustering followed by automated selection of the most suspicious cluster resulted in accurate ROIs in breast MRI lesions. J. Magn. Reson. Imaging 2007;26:606–614. © 2007 Wiley‐Liss, Inc.
Dynamic T1 mapping predicts outcome of chemoradiation therapy in primary rectal carcinoma: Sequence implementation and data analysis
Authors: Kremser Christian , Trieb Thomas , Rudisch Ansgar , Judmaier Werner , de Vries Alexander 
Published: August 2007

AbstractPurposeTo describe details about the implementation of a dynamic T1‐mapping technique and a simple data analysis strategy that can be used to predict therapy outcome in primary rectal carcinoma and to investigate the physiologic meaning of the obtained parameter.Materials and MethodsContrast‐enhanced dynamic T1 mapping was achieved with a snapshot fast low‐angle shot (FLASH) T1 mapping sequence implemented on a 1.5T MR scanner. This method was applied to 58 patients with primary rectal cancer before onset of chemoradiation therapy. A simple data analysis strategy based on the calculation of the maximum slope of the tissue concentration–time curve divided by the maximum of the arterial input function (AIF) was used as a measure of tumor microcirculation (PI values).ResultsThe snapshot FLASH (SFL) T1‐mapping technique is accurate and sensitive enough to detect inhomogeneous uptake kinetics within tumor tissue. Classifying the patients into two groups according to therapy response showed lower mean PI values for responders as compared to nonresponders. PI was found to combine information about permeability surface area product (PS) and blood volume.ConclusionsThe described method based on dynamic T1 mapping has the potential to be a clinical tool for predicting therapy outcome of preoperative chemoradiation in patients with primary rectal carcinoma. J. Magn. Reson. Imaging 2007;26:662–671. © 2007 Wiley‐Liss, Inc.
A new EPI‐based dynamic field mapping method: Application to retrospective geometrical distortion corrections
Authors: Lamberton Franck , Delcroix Nicolas , Grenier Denis , Mazoyer Bernard , Joliot Marc 
Published: August 2007

AbstractPurposeTo retrospectively correct for geometrical distortions, a new dynamic field mapping method suitable for dynamic single‐shot gradient‐echo type echo‐planar imaging (GRE‐EPI) is proposed.Materials and MethodsThe method requires a single volume additional acquisition and allows the extraction of a field map from each phase volume, assuming invariance across time of the echo time‐independent phase component. Performances of the method are assessed using three sets of experiments: the first tests the prerequisite and the modeling; the second tests the method with time‐dependent geometrical distortions; and the third presents a comparison with two other methods.ResultsOur results legitimize the modeling procedure and demonstrate that the dynamic method is less sensitive to noise than the other methods. A theoretical explanation for this is proposed in the discussion section.ConclusionGiven the minor increase in the acquisition time, this method is well suited for functional magnetic resonance imaging; prospective direction. J. Magn. Reson. Imaging 2007;26:747–755. © 2007 Wiley‐Liss, Inc.
Automated method for accurate abdominal fat quantification on water‐saturated magnetic resonance images
Authors: Peng Qi , McColl Roderick W. , Ding Yao , Wang Jihong , Chia Jonathan M. , Weatherall Paul T. 
Published: August 2007

AbstractPurposeTo introduce and evaluate the performance of an automated fat quantification method for water‐saturated magnetic resonance images.Materials and MethodsA fat distribution model is proposed for fat quantification on water saturated magnetic resonance images. Fat from both full‐ and partial‐volume voxels are accounted for in this model based on image intensity histogram analysis. An automated threshold method is therefore proposed to accurately quantify total fat. This method is compared to a traditional full‐volume‐fat‐only method in phantom and human studies. In the phantom study, fat quantification was performed on MR images obtained from a human abdomen oil phantom and was compared with the true oil volumes. In the human study, results of the two fat quantification methods of six subjects were compared on abdominal images with different spatial resolutions.ResultsIn the phantom study, the proposed method provided significantly more accurate estimations of true oil volumes compared to the reference method (P < 0.0001). In human studies, fat quantification using the proposed method gave much more consistent results on images with different spatial resolutions, and on regions with different degrees of partial volume averaging.ConclusionThe proposed automated method is simple, rapid, and accurate for fat quantification on water‐saturated MR images. J. Magn. Reson. Imaging 2007;26:738–746. © 2007 Wiley‐Liss, Inc.