bluuebunny/crossref_metadata_2025_split huggingface dataset:
Farmers' perceptions of the role of scattered vegetation in wind erosion control on arable land in Burkina Faso
Authors: Leenders J. K. , Visser S. M. , Stroosnijder L. 
Published: July 2005

AbstractThis paper describes the results of a survey on farmers' perceptions of the effect of woody natural vegetation on wind erosion. Sixty farmers were interviewed in three villages in northern Burkina Faso. The farmers mentioned that the presence of woody vegetation between the crops could benefit yield, but feared competition between the natural vegetation and the crop. Vegetation in a field was considered to increase deposition and decrease erosion on that field. The most important vegetative characteristics that affect wind erosion were, according to the farmers, vegetation's shape, porosity, flexibility and arrangement of the vegetation in the field. At present, most farmers do not apply this knowledge to the management of the natural woody vegetation on their fields. Copyright © 2005 John Wiley & Sons, Ltd.
Evolution of the southern Mu US desert in north China over the past 50 years: an analysis using proxies of human activity and climate parameters
Authors: Wang X. , Chen F.‐H. , Dong Z. , Xia D. 
Published: July 2005

AbstractMany previous studies have attributed the degradation in the Mu Us Desert in China to many centuries of human activity. The present study includes analysis of proxies of human activity such as arable land area, population and livestock number, and variations of precipitation, evaporation, temperature, sand‐driving wind and dust events, covering the period since 1950. It is demonstrated that desertification and vegetation rehabilitation during this period were principally related to the climatic variation, especially correlated to sand‐driving winds. It also suggests that the desert evolution in the past 2000 years was controlled by climate change rather than human activity. Although human activity was significant in the desert evolution processes over the past 50 years, the impacts seems to be overestimated in previous studies. Desertification and desert evolution in the Mu Us Desert are mainly in response to climatic trends and fluctuations. Copyright © 2005 John Wiley & Sons, Ltd.
Soil organic carbon stock for reclaimed minesoils in northeastern Ohio
Authors: Shukla M. K. , Lal R. 
Published: July 2005

AbstractReclamation of disturbed soils is done with the primary objective of restoring the land for agronomic or forestry land use. Reclamation followed by sustainable management can restore the depleted soil organic carbon (SOC) stock over time. This study was designed to assess SOC stocks of reclaimed and undisturbed minesoils under different cropping systems in Dover Township, Tuscarawas County, Ohio (40°32·33′ N and 81°33·86′ W). Prior to reclamation, the soil was classified as Bethesda Soil Series (loamy‐skeletal, mixed, acid, mesic Typic Udorthent). The reclaimed and unmined sites were located side by side and were under forage (fescue—Festuca arundinacea Schreb. and alfa grass—Stipa tenacissima L.), and corn (Zea mays L.)—soybean (Glycine max (L.) Merr.) rotation. All fields were chisel plowed annually except unmined forage, and fertilized only when planted to corn. The manure was mostly applied on unmined fields planted to corn, and reclaimed fields planted to forage and corn. The variability in soil properties (i.e., soil bulk density, pH and soil organic carbon stock) ranged from moderate to low across all land uses in both reclaimed and unmined fields for 0–10 and 10–20 cm depths. The soil nitrogen stock ranged from low to moderate for unmined fields and moderate to high in some reclaimed fields. Soil pH was always less than 6·7 in both reclaimed and unmined fields. The mean soil bulk density was consistently lower in unmined (1·27 mg m−3 and 1·22 mg m−3) than reclaimed fields (1·39 mg m−3 and 1·34 mg m−3) planted to forage and corn, respectively. The SOC and total nitrogen (TN) concentrations were higher for reclaimed forage (33·30 g kg−1; 3·23 g kg−1) and cornfields (21·22 g kg−1; 3·66 g kg−1) than unmined forage (17·47 g kg−1; 1·98 g kg−1) and cornfield (17·70 g kg−1; 2·76 g kg−1). The SOC stocks in unmined soils did not differ among forage, corn or soybean fields but did so in reclaimed soils for 0–10 cm depth. The SOC stock for reclaimed forage (39·6 mg ha−1 for 0–10 cm and 28·6 mg ha−1 for 10–20 cm depths) and cornfields (28·3 mg ha−1; 32·2 mg ha−1) were higher than that for the unmined forage (22·7 mg ha−1; 17·6 mg ha−1) and corn (21·5 mg ha−1; 26·8 mg ha−1) fields for both depths. These results showed that the manure application increased SOC stocks in soil. Overall this study showed that if the reclamation is done properly, there is a large potential for SOC sequestration in reclaimed soils. Copyright © 2005 John Wiley & Sons, Ltd.
Simulated rainfall evaluation of revegetation/mulch erosion control in the Lake Tahoe basin: 2. Bare soil assessment
Authors: Grismer M. E. , Hogan M. P. 
Published: July 2005

AbstractSlopes that have been disturbed through roadway, ski slope or other construction often produce more sediment than less disturbed sites. Reduction or elimination of sediment loading from such disturbed slopes to adjacent streams is critical in the Lake Tahoe basin. Here, use of a portable rainfall simulator (RS), described in the first paper of this series, is used to evaluate slope effects on erosion from bare volcanic and granitic soils (road cut and ski run sites) common in the basin in order to establish a basis upon which revegetation treatment comparisons can be made. Rainfall simulations (60 mm h−1, approximating a 100‐year, 15‐minute storm) at each site included multiple replications of bare soil plots as well as some adjacent ‘native’, or relatively undisturbed soils below trees where available. Field measurements of time to runoff, infiltration, runoff, sediment discharge rates, and average sediment concentration were obtained. Laboratory measurements of particle‐size distributions using sieve and laser counting methods indicated that the granitic soils had larger grain sizes than the volcanic soils and that road cut soils of either type also had larger grain sizes than their ski run counterparts. Particle‐size‐distribution‐based estimates of saturated hydraulic conductivity were 5–10 times greater than RS‐determined steady infiltration rates. RS‐measured infiltration rates were similar, ranging from 33–50 mm h−1 for disturbed volcanic soils and 33–60 mm h−1 for disturbed granitic soils. RS‐measured runoff rates and sediment yields from the bare soils were significantly correlated with plot slope with the exception of volcanic road cuts due to the narrow range of road cut slopes encountered. Sediment yields from bare granitic soils at slopes of 28 to 78 per cent ranged from ∼1 to 12 g m−2 mm−1, respectively, while from bare volcanic soils at slopes of 22 to 61 per cent they ranged from ∼3 to 31 g m−2 mm−1, respectively. Surface roughness did not correlate with runoff or erosion parameters, perhaps also as a result of a relatively narrow range of roughness values. The volcanic ski run soils and both types of road cut soils exhibited nearly an order of magnitude greater sediment yield than that from the corresponding native, relatively undisturbed, sites. Similarly, the granitic ski run soils produced nearly four‐times greater sediment concentration than the undisturbed areas. A possible goal of restoration/erosion control efforts could be recreation of ‘native’‐like soil conditions. Copyright © 2005 John Wiley & Sons, Ltd.
C1‐Symmetric Heterocyclic Zirconocenes as Catalysts for Propylene Polymerization, 2
Authors: Resconi Luigi , Guidotti Simona , Camurati Isabella , Frabetti Riccardo , Focante Francesca , Nifant'ev Ilya E. , Laishevtsev Ilya P. 
Published: July 2005

AbstractSummary: Sixteen C1‐symmetric zirconocene and one hafnocene complexes bearing the 2,5‐R2‐7H‐cyclopenta[1,2‐b:4,3‐b′]dithiophene ligand (R = H, Me, Et, Ph) linked to a substituted indenyl ligand have been synthesized and tested in propylene polymerization. Most of the C1‐symmetric zirconocenes of this type are highly active in propylene polymerization at low MAO/Zr ratios and produce poly(propylene)s (PP) in a broad range of isotacticity and melting points. The molecular weight and crystallinity of the PPs are strongly dependent upon the type of substituents on the indenyl moiety: PPs with Tm between 75 and 156 °C and viscosity average molecular weights between 100 000 and 400 000 have been obtained at 50–70 °C in liquid propylene.General formula of the indenyl‐based zirconocenes.magnified imageGeneral formula of the indenyl‐based zirconocenes.
Rheology of Polydisperse Star Polymer Melts: Extension of the Parameter‐Free Tube Model of Milner and McLeish to Arbitrary Arm‐Length Polydispersity
Authors: Slot Johan J. M. , Steeman Paul A. M. 
Published: July 2005

AbstractSummary: This paper considers the extension of the parameter‐free tube model of Milner and McLeish for stress relaxation in melts of monodisperse star polymers to star polymers whose arms have a continuous molecular weight distribution such as the Flory distribution in the case of star‐nylons and star‐polyesters. Exact expressions are derived for the relaxation spectrum and the relaxation modulus for star polymers having an arbitrary continuous arm‐length distribution. For a Flory distribution a comparison is made with results of dynamic measurements on a melt of 8‐arm poly(ε‐caprolactone) (PCL) stars. An excellent quantitative agreement over a large frequency range is found, however, only if one treats, in contrast with the original parameter‐free tube model approach, the entanglement molecular weight that determines the relaxation spectrum as a fitting parameter independent of the entanglement molecular weight of the linear PCL. This discrepancy is not in anyway related to the polydispersity in arm‐length, but a consequence of the thermorheological complexity of the PCL stars. A similar discrepancy has been observed for hydrogenated polybutadiene stars, as described by Levine and Milner.Measured and calculated storage moduli G′ as a function of frequency ω.magnified imageMeasured and calculated storage moduli G′ as a function of frequency ω.
Relationship between hallucinations, delusions, and rapid eye movement sleep behavior disorder in Parkinson's disease
Authors: Pacchetti Claudio , Manni Raffaele , Zangaglia Roberta , Mancini Francesca , Marchioni Enrico , Tassorelli Cristina , Terzaghi Michele , Ossola Maria , Martignoni Emilia , Moglia Arrigo , Nappi Giuseppe 
Published: July 2005

AbstractPsychotic symptoms are the main and the most disabling “nonmotor” complications of Parkinson's disease (PD), the pathophysiology of which is poorly recognized. Polysomnographic studies have shown a relationship between visual hallucinations and rapid eye movement (REM) sleep. The objective of this study is to clarify the relationship between psychotic symptoms and REM sleep behavior disorder (RBD) in PD. In a Parkinson's disease outpatient unit, 289 consecutive subjects with idiopathic PD were administered (in the period from January to December 2002) a multiple‐choice questionnaire and structured interview on sleep and mental disorders. RBD was diagnosed in accordance with the minimal diagnostic criteria of the International Classification of Sleep Disorders. Hallucinations and delusional disorders were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders‐IV criteria. The presence or absence of psychotic symptoms, of RBD, and of daytime sleepiness, as well as motor status, cognitive status, and mood were assessed. Approximately 32% (n = 92) of the subjects presented with psychotic disorders; 30% (n = 86) had experienced hallucinations; 2% (n = 6) had delusions without hallucinations. Sixty‐two (72%) hallucinators reported nocturnal hallucinations. A total of 6.6% (n = 19) of the subjects complained of a delusional disorder. There were 26.6% (n = 77) of subjects who presented with RBD: 28 (36%) with onset before and 49 (63%) with onset after PD diagnosis. The presence of RBD was associated with an increased risk of manifesting hallucinations and delusions (odds ratio [OR], 2.73). Other independent clinical factors found to have an effect on psychotic disorders were cognitive impairment (OR, 3.92), disease duration (OR, 2.46), advanced age (OR, 2.34), and severity of motor symptoms (OR, 2.06). These results suggest that RBD is widely associated with psychosis in PD. © 2005 Movement Disorder Society
Concurrent fMRI and optical measures for the investigation of the hemodynamic response function
Authors: Kennerley Aneurin J. , Berwick Jason , Martindale John , Johnston David , Papadakis Nikos , Mayhew John E. 
Published: July 2005

AbstractFunctional magnetic resonance imaging (fMRI) signal variations are based on a combination of changes in cerebral blood flow (CBF) and volume (CBV), and blood oxygenation. We investigated the relationship between these hemodynamic parameters in the rodent barrel cortex by performing fMRI concurrently with laser Doppler flowmetry (LDF) or optical imaging spectroscopy (OIS), following whisker stimulation and hypercapnic challenge. A difference between the positions of the maximum blood oxygenation level‐dependent (BOLD) and CBV changes was observed in coronal fMRI maps, with the BOLD region being more superficial. A 6.5% baseline blood volume fraction in this superficial region dropped to 4% in deeper cortical layers (corresponding to total hemoglobin baseline volumes Hbt0 = 110 μM and 67 μM, respectively), as inferred from maps of ΔR. Baseline volume profiles were used to parameterize the Monte Carlo simulations (MCS) to interpret the 2D OIS. From this it was found that the optical blood volume measurements (i.e., changes in total hemoglobin) equated with CBV‐MRI measurements when the MRI data were taken from superficial cortical layers. Optical measures of activation showed a good spatial overlap with fMRI measurements taken in the same plane (covering the right hemisphere surface). Changes in CBV and CBF followed the scaling relationship CBV = CBFα, with mean α = 0.38 ± 0.06. Magn Reson Med 54:354–365, 2005. © 2005 Wiley‐Liss, Inc.
Influence of gradient acoustic noise on fMRI response in the human visual cortex
Authors: Zhang Nanyin , Zhu Xiao‐Hong , Chen Wei 
Published: July 2005

AbstractA paired‐stimuli paradigm combined with fMRI was utilized to study the effect of gradient acoustic noise on fMRI response in the human primary visual cortex (V1) in terms of the auditory‐visual cross‐modal neural interaction. The gradient noise generated during the fMRI acquisition was used as the primary stimulus, and a single flashing light was used as the secondary stimulus. An interstimulus interval (ISI) separated the two. Six tasks were designed with different ISIs ranging from 50 to 700 ms. Both BOLD signal intensity and the number of activated pixels in V1 were analyzed and examined, and they showed a significant reduction when the gradient noise preceded the flashing light by ∼300 ms. These results indicate that the gradient acoustic noise generated during fMRI acquisitions does interfere with neural behavior and the BOLD signal in the human visual cortex. This interference is modulated by the delay between the gradient noise and visual stimulation, and it can be studied quantitatively when the stimulation paradigm is designed appropriately. This study provides evidence of the auditory–visual interaction during fMRI studies, and the results should have an impact on fMRI applications. Magn Reson Med 54:258–263, 2005. © 2005 Wiley‐Liss, Inc.
How does DWI correlate with white matter structures?
Authors: Ronen Itamar , Ugurbil Kamil , Kim Dae‐Shik 
Published: July 2005

AbstractDiffusion‐weighted MRI (DWI) is widely used to characterize brain white matter (WM), particularly through the use of diffusion tensor imaging (DTI). In this study the spatial characteristics of DWI in WM of cat visual cortex were investigated at 9.4T at very high resolution. It is shown that the spatial extent of the WM tract as measured from the DWI images depends highly on theb‐value. In particular, when the diffusion gradient is applied perpendicular to the main direction of the fiber tract, the estimated thickness of the tract at the commonly usedb‐value of 1000 s/mm2exceeds by 50% the thickness as it appears on aT2‐weighted image. Only atb‐values greater than 6000 s/mm2does the thickness of the tract approach the thickness characterized by theT2‐weighted image and that observed on histological slices of the same area. Further analysis of these results indicates that the choice ofb‐value of 1000 s/mm2may not be optimal for the demarcation of anisotropic WM structures. DWI at highb‐value may contain spatial information that is more specific to WM tracts. Magn Reson Med 54:317–323, 2005. © 2005 Wiley‐Liss, Inc.
Estimation of renal extraction fraction based on postcontrast venous and arterial differential T1 values: An error analysis
Authors: Levin Yakir S. , Chow Lawrence C. , Pelc Norbert J. , Sommer F. Graham , Spielman Daniel M. 
Published: July 2005

AbstractAn error analysis for quantifying single kidney extraction fraction (EF) via differential T1 measurements in the renal vein (RV) and renal artery (RA) is presented. Sources of error include blood flow effects, the effect of a short repetition time (TR), and the impact of uncertainties in the T1 estimates on the final EF calculations. Blood flow effects were investigated via simulation. For a range of blood velocities in the renal vein that may be found in kidney disease, incomplete refreshment of blood between readouts results in significant errors in T1 estimation. For a .5‐cm slice, 110‐ms sampling interval, and T1 of 600 ms, T1 estimation to within 5% of true T1 requires an average through‐plane velocity of 6.75 cm/s for parabolic flow, and 3.5 cm/s for plug flow. Improvement can be achieved by accurately estimating the fraction of blood that has not refreshed between readouts (fold), while the quality of the T1 estimate varies with the accuracy of fold estimation. Shortening of the TR was investigated using phantom and in vivo studies. T1 was estimated to within 3% of the true value on phantoms, and within 5% of the true value for flowing blood for TR = 2T1. The estimated EF is shown to be very sensitive to the difference between T1RA and T1RV. To achieve 10% or 20% uncertainty in the EF estimate, T1 in the renal vein and renal artery must be estimated to within approximately 1% or 2%. Because of limitations on measurement accuracy and precision, this method appears to be impractical at this time. Magn Reson Med 54:309–316, 2005. © 2005 Wiley‐Liss, Inc.
Quantification of cerebral arterial blood volume and cerebral blood flow using MRI with modulation of tissue and vessel (MOTIVE) signals
Authors: Kim Tae , Kim Seong‐Gi 
Published: July 2005

AbstractRegional cerebral arterial blood volume (CBVa) and blood flow (CBF) can be quantitatively measured by modulation of tissue and vessel (MOTIVE) signals, enabling separation of tissue signal from blood. Tissue signal is selectively modulated using magnetization transfer (MT) effects. Blood signal is changed either by injection of a contrast agent or by arterial spin labeling (ASL). The measured blood volume represents CBVa because the contribution from venous blood was insignificant in our measurements. Both CBVa and CBF were quantified in isoflurane‐anesthetized rats at 9.4T. CBVa obtained using a contrast agent was 1.1 ± 0.5 and 1.3 ± 0.6 ml/100 g tissue (N = 10) in the cortex and caudate putamen, respectively. The CBVa values determined from ASL data were 1.0 ± 0.3 ml/100 g (N = 10) in both the cortex and the caudate putamen. The match between CBVa values determined by both methods validates the MOTIVE approach. In ASL measurements, the overestimation in calculated CBF values increased with MT saturation levels due to the decreasing contribution from tissue signals, which was confirmed by the elimination of blood with a contrast agent. Using the MOTIVE approach, accurate CBF values can also be obtained. Magn Reson Med 54:333–342, 2005. © 2005 Wiley‐Liss, Inc.
Novel method to estimate and display cerebral cortical degeneration using diffusion‐weighted magnetic resonance imaging
Authors: Yoshiura Takashi , Mihara Futoshi , Tanaka Atsuo , Noguchi Tomoyuki , Togao Osamu , Kuwabara Yasuo , Honda Hiroshi 
Published: July 2005

AbstractPrevious studies have shown that diffusion‐weighted imaging (DWI) is useful for detecting microstructural degradation of neuronal tissue in neurodegenerative diseases. Mapping of cortical degeneration by DWI is potentially useful, but is extremely difficult, mainly because of the partial volume effect resulting from the surrounding cerebrospinal fluid (CSF). In this study a novel method to map and display the cortical damage in neurodegenerative diseases using DWI is proposed. Instead of measuring the cortical diffusivity, the diffusivity of white matter directly beneath the cortex, where neuronal fibers enter or exit the overlying cortex, was measured and mapped onto the cortical surface. The map was viewed in a form of three‐dimensional (3D) rendering. Patients with Alzheimer's disease (AD) showed cortical damage in the temporal and parietal cortices, and a patient with frontotemporal dementia showed damage in the frontal lobe, consistent with the typical topographical distribution of histopathological cortical damage in each of these diseases. The results suggest that subcortical diffusivity closely reflects cortical damage, and that the current mapping technique is a promising tool for evaluating neurodegenerative diseases. Magn Reson Med 54:455–459, 2005. © 2005 Wiley‐Liss, Inc.
Optimizing brain tissue contrast with EPI: A simulated annealing approach
Authors: Ikonomidou Vasiliki N. , van Gelderen Peter , de Zwart Jacco A. , Fukunaga Masaki , Duyn Jeff H. 
Published: July 2005

AbstractA new magnetization preparation and image acquisition scheme was developed to obtain high‐resolution brain images with optimal tissue contrast. The pulse sequence was derived from an optimization process using simulated annealing, without prior assumptions with regard to the number of radiofrequency (RF) pulses and flip angles. The resulting scheme combined two inversion pulses with the acquisition of three images with varying contrast. The combination of the three images allowed separation of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) based on T1, contrast. It also enabled the correction of small errors in the initial T1 estimates in postprocessing. The use of three‐dimensional (3D) sensitivity‐encoded (SENSE) echo‐planar imaging (EPI) for image acquisition made it possible to achieve a 1.153 mm3 isotropic resolution within a scan time of 10 min 21 s. The cortical GM signal‐to‐noise ratio (SNR) in the calculated GM‐only image varied between 30 and 100. The novel technique was evaluated in combination with blood oxygen level‐dependent (BOLD) functional magnetic resonance imaging (fMRI) on human subjects, and provided for excellent coregistration of anatomical and functional data. Magn Reson Med 54:373–385, 2005. Published 2005 Wiley‐Liss, Inc.