bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of catchment properties on runoff coefficient in a karst area of southwest China
Authors: Zhang Zhicai , Chen Xi , Huang Yuanyang , Zhang Yanfang 
Published: May 2013

AbstractFrequent human activities and climate change in the karst region of southwest China since the 1950s have led to the investigation of response of runoff to climate and catchment properties. Runoff coefficient (Rc) as an expression variable of the catchment response to rainfall is important to describe runoff dynamics and to estimate available streamflow for utilization. In this study, the equations of Rc associated with its attributors of climate condition and catchment property were derived using the Budyko framework. The equations were used to estimate relationship between the Rc and the attributors in the karst catchments in Guizhou province of southwest China. Analysis in the selected 23 karst catchments demonstrates that the spatial distribution of Rc is dominated by the catchment properties, such as the catchment properties of geology, slope and land use and land cover, rather than climate condition of drought index. Correlation analysis indicates that the catchment with a large slope usually has a high value of Rc, and a large proportion of carbonate rock in a catchment reduces Rc in the study area. Temporal increasing trend of Rc during 1961–2000 was found for most catchments in the study area. This increasing trend was primarily resulted from changes of catchment properties, e.g. deforestation in large areas of Guizhou province during the 1950s–1980s. Copyright © 2013 John Wiley & Sons, Ltd.
Residence time control on hot moments of net nitrate production and uptake in the hyporheic zone
Authors: Briggs Martin A. , Lautz Laura K. , Hare Danielle K. 
Published: May 2013

AbstractThe retention capacity for biologically available nitrogen within streams can be influenced by dynamic hyporheic zone exchange, a process that may act as either a net source or net sink of dissolved nitrogen. Over 5 weeks, nine vertical profiles of streambed chemistry (NO3− and NH4+) were collected above two beaver dams along with continuous high‐resolution vertical hyporheic flux data. The results indicate a non‐linear relation of net NO3− production followed by net uptake in the hyporheic zone as a function of residence time. This Lagrangian‐based relation is consistent through time and across varied morphology (bars, pools, glides) above the dams, even though biogeochemical and environmental factors varied. The empirical continuum between net NO3− production and uptake and residence time is useful for identifying two crucial residence time thresholds: the transition to anaerobic respiration, which corresponds to the time of peak net nitrate production, and the net sink threshold, which is defined by a net uptake in NO3− relative to streamwater. Short‐term hyporheic residence time variability at specific locations creates hot moments of net production and uptake, enhancing NO3− production as residence times approach the anaerobic threshold, and changing zones of net NO3− production to uptake as residence times increase past the net sink threshold. The anaerobic and net sink thresholds for beaver‐influenced streambed morphology occur at much shorter residence times (1.3 h and 2.3 h, respectively) compared to other documented hyporheic systems, and the net sink threshold compares favorably to the lower boundary of the anaerobic threshold determined for this system with the new oxygen Damkohler number. The consistency of the residence time threshold values of NO3− cycling in this study, despite environmental variability and disparate morphology, indicates that NO3− hot moment dynamics are primarily driven by changes in physical hydrology and associated residence times. Copyright © 2013 John Wiley & Sons, Ltd.
EVALUATING WATER POLICY OPTIONS IN AGRICULTURE: A WHOLE‐FARM STUDY FOR THE BROYE RIVER BASIN (SWITZERLAND)
Authors: Lehmann Niklaus , Finger Robert 
Published: May 2013

ABSTRACTIn this study, we evaluate the impact of an increased volumetric water price and the implementation of a water quota on management decisions, income, income risk and utility of an arable farmer in the Broye River Basin, western Switzerland. We develop a bio‐economic whole‐farm model, which couples the process‐based crop growth model CropSyst with an economic decision model at farm scale and use a genetic algorithm as optimization technique. This integrated modelling approach is employed to optimize the farmer's management decisions with regard to crop land use as well as crop‐specific nitrogen fertilization and irrigation intensities under different climate and water policy scenarios. Our results show that the farm's water demand will increase by almost 100% under climate change. However, both, an increased volumetric water price and a water quota, are under current and future expected climate conditions effective policy measures to reduce the farm's water consumption. At the same time, due to adjustments in the crop mix as well as in crop‐specific nitrogen fertilization and irrigation strategies, both policies lead to losses in farm income and in the farmer's utility of only about 10%. Nevertheless, a higher water price as well as a water quota increase under future expected climate conditions the crop farm's downside risk exposure (i.e. probability of low farm incomes). Copyright © 2013 John Wiley & Sons, Ltd.
LIVE BED SCOUR AT A SIDE‐WEIR INTERSECTION LOCATED ON AN ALLUVIAL CHANNEL
Authors: Onen F. , Agaccioglu H. 
Published: May 2013

ABSTRACTThis study aims to obtain both the depth of clear water and live bed scour around side‐weirs located on an alluvial channel for sharp‐crested side‐weirs under subcritical flow conditions. At the downstream end of the side‐weir, a longitudinal bar in the middle of the channel and a scour hole close to the outer bank are formed because of changes in shear stress field and velocities. Dimensionless depth of scour increases with an increase of the dimensionless parameters of flow depth, side‐weir length and sediment size. The dimensionless depth of scour increases almost linearly with the dimensionless parameter of flow velocity for clear water scour, and it decreases for live bed conditions at the straight channel due to the decreasing deviation angle and kinetic energy toward the side‐weirs and bed material coming from upstream of the main channel. Because of the effect of the helicoidal flow created by bends, the dimensionless depth of scour fluctuated with the dimensionless parameter of flow velocity at the maximum value of clear water scour for movable bed conditions at a bend. At the 30° section of a bend, the equilibrium depth of scour is achieved as maximum values due to the deviation on the path of maximum velocity towards the outer bank. Copyright © 2013 John Wiley & Sons, Ltd.
NEW EQUATIONS FOR THE DETERMINATION OF SOIL SATURATED HYDRAULIC CONDUCTIVITY USING THE VAN GENUCHTEN MODEL PARAMETERS AND EFFECTIVE POROSITY
Authors: Aschonitis Vassilis G. , Antonopoulos Vassilis Z. 
Published: May 2013

ABSTRACTModifications of the Kozeny–Carman approach (Ks = AΦB) for the determination of saturated hydraulic conductivity Ks using the van Genuchten model parameters and the effective porosity Φe are presented in this study. Two models {a two‐parametric Ks(a, Φe) and a three‐parametric Ks(a, Si, Φe)} were developed for Ks determination. In the two‐parametric model the power constant was replaced by the f factor (f = aΦe). The factor f includes the parameter a of the van Genuchten model, in order to describe its effect on the part of the pore size distribution which participates in the effective porosity Φe. The three‐parametric model was improved by inclusion of the water retention curve slope Si at the inflection point. The models were calibrated and validated using two published data sets which cover the 12 USDA soil texture classes. The proposed models were also compared with other published models of Ks, which are based on the van Genuchten parameters and the Kozeny–Carman approach. The results indicated an adequate predictive accuracy of the models through a calibration and validation procedure using data sets from different sources and better performance compared to other models, setting a new approach for the indirect determination of Ks using only data from the water retention curve. Copyright © 2013 John Wiley & Sons, Ltd.
A Semi‐Physiological Model of Amyloid‐β Biosynthesis and Clearance in Human Cerebrospinal Fluid: A Tool for Alzheimer's Disease Research and Drug Development
Authors: Haug Karin G. , Staab Alexander , Dansirikul Chantaratsamon , Lehr Thorsten 
Published: May 2013

AbstractStable isotope labeling kinetics (SILK) was successfully applied to quantify endogenous amyloid‐β (Aβ) metabolism in human cerebrospinal fluid (CSF). A semi‐physiological model describing Aβ biosynthesis and degradation in human CSF and the impact of the γ‐secretase inhibitor semagacestat should be developed and validated based on digitized data from three published SILK studies. Aβ biosynthesis was adequately characterized by six transit compartments. At each transition step, a first‐order degradation process was implemented. A two‐compartment model best described semagacestat CSF concentration‐time profiles. Semagacestat concentrations were linked to the Aβ production by an inhibitory Emax model. For model validation, three individual Aβ profiles from literature were successfully predicted. Model application demonstrated a 35% decreased Aβ elimination rate constant in Alzheimer's disease (AD) patients. Study design optimization revealed that SILK studies could be conducted with significant less sampling points compared to the standard protocol without losing information about the Aβ metabolism, if analyzed by the presented model. In conclusion, the analysis outlined the advantages and opportunities of integrating all available data and knowledge into a semi‐physiological model. The model can serve as valuable tool for researchers and clinicians interested in the pathology of AD as well as in the development of new therapeutics for AD.
Detection of CD133 (prominin‐1) in a human hepatoblastoma cell line (HuH‐6 clone 5)
Authors: Akita Masumi , Tanaka Kayoko , Murai Noriko , Matsumoto Sachiko , Fujita Keiko , Takaki Takashi , Nishiyama Hidetoshi 
Published: May 2013

ABSTRACTWe examined CD133 distribution in a human hepatoblastoma cell line (HuH‐6 clone 5). We directly observed the cultured cells on a pressure‐resistant thin film (silicon nitride thin film) in a buffer solution by using the newly developed atmospheric scanning electron microscope (ASEM), which features an open sample dish with a silicon nitride thin film window at its base, through which the scanning electron microscope beam scans samples in solution, from below. The ASEM enabled observation of the ventral cell surface, which could not be observed using standard SEM. However, observation of the dorsal cell surface was difficult with the ASEM. Therefore, we developed a new method to observe the dorsal side of cells by using Aclar® plastic film. In this method, cells are cultured on Aclar plastic film and the dorsal side of cells is in contact with the thin silicon nitride film of the ASEM dish. A preliminary study using the ASEM showed that CD133 was mainly localized in membrane ruffles in the peripheral regions of the cell. Standard transmission electron microscopy and scanning electron microscopy revealed that CD133 was preferentially concentrated in a complex structure comprising filopodia and the leading edge of lamellipodia. We also observed co‐localization of CD133 with F‐actin. An antibody against CD133 decreased cell migration. Methyl‐β‐cyclodextrin treatment decreased cell adhesion as well as lamellipodium and filopodium formation. A decrease in the cholesterol level may perturb CD133 membrane localization. The results suggest that CD133 membrane localization plays a role in tumor cell adhesion and migration. Microsc. Res. Tech. 76:844–852, 2013. © 2013 Wiley Periodicals, Inc.
Long‐term loss and re‐formation of the outer radiation belt
Authors: Lee D.‐Y. , Shin D.‐K. , Kim J.‐H. , Cho J.‐H. , Kim K.‐C. , Hwang J. A. , Turner D. L. , Kim T. K. , Park M.‐Y. 
Published: May 2013

AbstractThe Earth's outer radiation belt is known to vary often and significantly on various time scales. In this study, we have used the data of various instruments onboard the THEMIS spacecraft to study long‐term changes of the outer radiation belt electrons around the year 2009. We find that the entire outer belt became extremely weak for nearly a year and was practically lost a few times, each time lasting ~20 days up to ~2 months, before eventually re‐forming. This was revealed at a wide energy range from several tens of keV to up to 719 keV, which was covered by the THEMIS spacecraft measurements. The loss of the outer belt was associated with extremely weak solar wind conditions, i.e., low interplanetary magnetic field magnitude and slow solar wind speed. In particular, this set greatly reduced magnetospheric convection and/or injections for a prolonged time interval, which led to a large expansion of the plasmasphere, even beyond geosynchronous altitude and thus invading the majority of the typical outer belt territory for the same prolonged time interval. Consequently, preexisting electrons inside the plasmasphere had enough time to be lost into the atmosphere gradually over a time scale of several days without being supplied with fresh electrons from the plasma sheet under the same reduced convection and/or injections. Plasmaspheric hiss waves with an amplitude of up to a few tens of pT persisted to exist during the gradual decay periods, implying that they are likely responsible for the continual loss of the electrons inside the plasmasphere. A complete re‐formation of the outer belt to full intensity was then realized over an interval of a few months. During the re‐formation process, the magnetospheric convection and/or injections increased, which led to a gradual increase of whistler chorus wave activity, contraction of the plasmasphere, and supply of the plasma sheet electrons at high L shells. This set first an outward increasing profile of the phase space density, which eventually developed into a profile with a peak at low L of ~5 over a time scale of 1–2 days. In this latter stage, a local acceleration at low L shells is found to be clearly needed although the radial diffusion process can contribute to some extent, in particular, for particles with a low first adiabatic invariant value.
The response of coastal stratocumulus clouds to agricultural irrigation in California
Authors: Lo Min‐Hui , Wu Chien‐Ming , Ma Hsi‐Yen , Famiglietti James S. 
Published: May 2013

AbstractStratocumulus clouds (SC) often exist over the eastern subtropical oceans during the summer and have significant impacts on the surface radiation budget. Both atmospheric subsidence and lower troposphere stability (LTS) have been found to play important roles in maintaining SC. Using global climate model simulations, we find that irrigation in California's Central Valley results in a decrease of land surface temperature, leading to a smaller land‐sea heat contrast, and a corresponding reduction in sea breeze, subsidence, and LTS over the near‐coastal region. The decrease in LTS directly drives a reduction in modeled SC coverage, and it would arguably do so in reality because of the well‐known link between LTS and SC coverage. Consequently, simulated absorbed surface solar radiation over this region increases by 8 W/m2 (3.7%) due to the reduction in SC cover, resulting in the warming at the Earth's surface. This study has important implications for how SC can change with regard to future climate. In contrast to the general effects of climate change on the formation of SC, our results suggest that irrigation practices in the Central Valley may drive a decrease in nearby SC coverage.
Surgical treatment of sleep apnea: Association between surgeon/hospital volume with outcomes
Authors: Capobianco Dirce M. , Batilana Adelia , Gandhi Mihir , Shah Jatin , Ferreira Rodrigo , Carvalho Elias , Rivero Thiago S. , Pietrobon Ricardo , Atallah Álvaro N. , Prado Gilmar F. 
Published: May 2013

Objectives/HypothesisTo identify the association between surgeon/hospital volume with outcomes in surgical treatment for obstructive sleep apnea (OSA) in a nationally representative sample. We hypothesized that surgeons/hospitals with lower patient volumes would have: higher mortality rates, longer hospital length of stay (LOS), and higher postoperative complication rates and hospitalization charges.Study DesignSecondary data analysis of the 2007 Nationwide Inpatient Sample database.MethodsWe selected 24,298 adults undergoing OSA surgery. The data analysis included trend test, regression, and multivariate models that were adjusted by demographic and clinical variables.ResultsThe patients were mostly White (76.43%), male (78.26%), with a mean age of 46 years. Patients treated by surgeons with low volume of procedures (1 procedure/year) had significantly higher mortality rate (odds ratio [OR] 3.05; confidence interval [CI], 1.96‐4.77), longer average LOS (increased until 8.16 hours), and higher hospitalization charges (increased up to $1701.75) versus medium‐ and high‐volume surgeons (2–4 procedures/year; greater than/or equal to 5 procedures/year, respectively). Patients treated at hospitals with low volume of procedures (0–5/year) had significantly higher occurrence of oxygen desaturation (OR, 2.12; CI, 1.50–2.99), longer LOS (increased until almost 2 hours) and higher hospitalization charges (at least $951.50 more expensive) versus patients treated at high‐volume hospitals (greater than/or equal to 18 procedures/year).ConclusionOur investigation validates the hypothesis that lower volume standards (surgeon/hospital) are associated with increase of LOS following surgery to treat OSA, as well as lower surgeon volume associated with increase of mortality and hospitalization charges and lower hospital volume with occurrence of oxygen desaturation as postoperative complication.Level of Evidence2c. Laryngoscope, 124:320–328, 2014
Effects of asymmetric superior laryngeal nerve stimulation on glottic posture, acoustics, vibration
Authors: Chhetri Dinesh K. , Neubauer Juergen , Bergeron Jennifer L. , Sofer Elazar , Peng Kevin A. , Jamal Nausheen 
Published: May 2013

Objectives/HypothesisEvaluate the effects of asymmetric superior laryngeal nerve stimulation on the vibratory phase, laryngeal posture, and acoustics.Study DesignBasic science study using an in vivo canine model.MethodsThe superior laryngeal nerves were symmetrically and asymmetrically stimulated over eight activation levels to mimic laryngeal asymmetries representing various levels of superior laryngeal nerve paresis and paralysis conditions. Glottal posture change, vocal fold speed, and vibration of these 64 distinct laryngeal‐activation conditions were evaluated by high speed video and concurrent acoustic and aerodynamic recordings. Assessments were made at phonation onset.ResultsVibratory phase was symmetric in all symmetric activation conditions, but consistent phase asymmetry toward the vocal fold with higher superior laryngeal‐nerve activation was observed. Superior laryngeal nerve paresis and paralysis conditions had reduced vocal fold strain and fundamental frequency. Superior laryngeal nerve activation increased vocal fold closure speed, but this effect was more pronounced for the ipsilateral vocal fold. Increasing asymmetry led to aperiodic and chaotic vibration.ConclusionsThis study directly links vocal‐fold tension asymmetry with vibratory phase asymmetry, in particular the side with greater tension leads in the opening phase. The clinical observations of vocal fold lag, reduced vocal range, and aperiodic voice in superior laryngeal paresis and paralysis is also supported.Level of EvidenceN/A. Laryngoscope, 123:3110–3116, 2013
Salivary endoscopy for idiopathic chronic sialadenitis
Authors: Vashishta Rishi , Gillespie M. Boyd 
Published: May 2013

Objectives/HypothesisTo describe the findings and therapeutic role of salivary endoscopy for idiopathic chronic sialadenitis.Study DesignRetrospective case series.MethodsThe records of 258 patients who underwent salivary endoscopy between November 2008 and May 2012 were reviewed. Included cases presented with recurrent inflammation and swelling of a single major salivary gland, without identifiable etiology on examination and imaging.ResultsA total of 51 cases (20%) were identified. These patients had a mean age of 54.4 years (range, 23–75) and 57% were female. Mean duration of symptoms was 22.8 months (range, 1–102), with most cases (75%) involving the parotid gland. The primary imaging modalities used were ultrasound (62%) and computed tomography (31%). The most common findings on imaging included ductal dilation (42%), enlarged lymph nodes (23%), normal glandular imaging (15%), and possible sialoliths (14%). The most common findings on salivary endoscopy included stenosis (57%), strictures (27%), and inflammatory debris (18%). Occult stones were the cause of sialadenitis in only 4 (8%) cases. Outcomes included complete symptom resolution in 31 patients (61%), improved but occasional symptoms in 14 patients (27%), and no improvement in 6 patients (12%) after a mean follow‐up time of 20.0 months (range, 4–45). Excision of the involved gland was required in 2 (4%) patients.ConclusionSalivary endoscopy is a minimally invasive technique that is effective in the management of idiopathic chronic sialadenitis refractory to medical therapy. It provides diagnostic information in most patients and offers a therapeutic intervention with gland preservation.Level of Evidence4. Laryngoscope, 123:3016–3020, 2013
Efficacy of intra‐ and extraturbinal microdebrider turbinoplasty in perennial allergic rhinitis
Authors: Lee Jae Yong 
Published: May 2013

Objectives/HypothesisMicrodebrider‐assisted inferior turbinoplasty (MAIT) has become a popular method for relieving symptoms of allergic rhinitis and can be performed intraturbinally or extraturbinally. The objective of this study was to evaluate and compare the long‐term efficacy of these two methods.Study DesignProspective randomized study.MethodsSixty patients diagnosed with perennial allergic rhinitis were selected. Thirty patients were treated with intraturbinal MAIT (group 1) and 30 patients were treated with extraturbinal MAIT (group 2). Postoperative changes in nasal obstruction, rhinorrhea, sneezing, nasal itching, and postnasal drip were evaluated 3, 6, and 12 months postoperatively. The cross‐sectional area of the second notch and nasal cavity volume were compared at 12 months. The operation time, duration of crust formation, and postoperative bleeding were also compared.ResultsAll symptoms improved significantly in both groups at 3, 6, and 12 months. However, when improvement of rhinorrhea, sneezing, and nasal itching was compared, improvement was statistically significant in group 2 at 12 months. Acoustic rhinometry demonstrated a significant increase in the cross‐sectional area of the second notch and nasal cavity volume in both groups, which did not differ significantly between the two groups at 12 months. The operation time and duration of crust formation were longer in groups 1 and 2, respectively. The incidence of postoperative bleeding was higher in group 2.ConclusionAlthough both methods showed significant improvement, extraturbinal MAIT seemed more effective for long‐term relief of allergic symptoms. However, the advantages and disadvantages of each method should be considered before choosing the surgical technique.Level of Evidence1b. Laryngoscope, 123:2945–2949, 2013