bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Application of Nonlinear Local Lyapunov Vectors to Ensemble Predictions in Lorenz Systems
Authors: Feng Jie , Ding Ruiqiang , Liu Deqiang , Li Jianping 
Published: April 2014

Abstract
Nonlinear local Lyapunov vectors (NLLVs) are developed to indicate orthogonal directions in phase space with different perturbation growth rates. In particular, the first few NLLVs are considered to be an appropriate orthogonal basis for the fast-growing subspace. In this paper, the NLLV method is used to generate initial perturbations and implement ensemble forecasts in simple nonlinear models (the Lorenz63 and Lorenz96 models) to explore the validity of the NLLV method.
The performance of the NLLV method is compared comprehensively and systematically with other methods such as the bred vector (BV) and the random perturbation (Monte Carlo) methods. In experiments using the Lorenz63 model, the leading NLLV (LNLLV) captured a more precise direction, and with a faster growth rate, than any individual bred vector. It may be the larger projection on fastest-growing analysis errors that causes the improved performance of the new method. Regarding the Lorenz96 model, two practical measures—namely the spread–skill relationship and the Brier score—were used to assess the reliability and resolution of these ensemble schemes. Overall, the ensemble spread of NLLVs is more consistent with the errors of the ensemble mean, which indicates the better performance of NLLVs in simulating the evolution of analysis errors. In addition, the NLLVs perform significantly better than the BVs in terms of reliability and the random perturbations in resolution.
Analytical Study of an Isotropic Viscoplastic Sea Ice Model in Idealized Configurations
Authors: Sirven Jérôme , Tremblay Bruno 
Published: April 2014

AbstractAnalytic solutions of a mechanical sea ice model are computed in idealized configurations. They are then used to study the properties of this model. It classically assumes that the ice behaves at large scale as an isotropic viscoplastic medium. The plastic regime is characterized by a Mohr–Coulomb yield curve. The flow rule corresponds to the one used in granular mediums and depends on a parameter δ that characterizes the expansion properties of the medium. Using simple model configurations, this study first shows that a sliding of the ice along the coast must be permitted; otherwise, the model generally has no solution when the plastic regime is active. This study then shows that the viscous regime is reached only if the stress remains nearly uniform over a large area. For a stress having no particular properties, the plastic regime acts everywhere. In this case, the compressive stress may reach the maximum value allowed by the model close to the coastline. The extension of the domain where the compressive stress is at its maximum depends on δ and the direction of the forcing field. Over this domain, the ice behaves as a fluid material with a small negative viscosity. Last, the authors found that neither the existence of the solution nor its unicity are guaranteed in this stationary model. This result does not imply that the unicity is lost in the transient problem; it suggests that the evolution of sea ice depends not only on the forcing, but also on the initial conditions or history of the system.
Vortical and Internal Wave Shear and Strain
Authors: Pinkel Robert 
Published: April 2014

Abstract
Depth–time records of isopycnal vertical strain have been collected from intensive CTD profiling programs on the research platform (R/P) Floating Instrument Platform (FLIP). The associated vertical wavenumber frequency spectrum of strain, when viewed in an isopycnal-following frame, displays a clear spectral gap at low vertical wavenumber, separating the quasigeostrophic (vortical) strain field and the superinertial internal wave continuum. This gap enables both model and linear-filter-based methods for separating the submesoscale and internal wave strain fields. These fields are examined independently in six field programs spanning the period 1983–2002. Vortical and internal wave strain variances are often comparable in the upper thermocline, of order 0.2. However, vortical strain tends to decrease with increasing depth (decreasing buoyancy frequency as ~(N2)1/2, while internal wave strain variance increases as ~(N2)−1/2, exceeding vortical variance by a factor of 5–10 at depths below 500 m.
In contrast to strain, the low-frequency spectral gap in the shear spectrum is largely obscured by Doppler-smeared near-inertial motions. The vertical wavenumber spectrum of anticyclonic shear exceeds the cyclonic shear and strain spectra at all scales greater than 10 m. The frequency spectrum of anticyclonic shear exceeds that of both cyclonic shear and strain to frequencies of 0.5 cph, emphasizing the importance of lateral Doppler shifting of near-inertial shear.
The limited Doppler shifting of the vortical strain field implies surprisingly small submesoscale aspect ratios: kH/kz ~ 0.001, Burger numbers Br = kH N/kzf ~ 0.1. Submesoscale potential vorticity is dominated by vertical straining rather than the vertical component of relative vorticity. The inferred rms fluctuation of fluid vorticity is far less for the vortical field than for the internal wavefield.
Shipborne Polarimetric Weather Radar: Impact of Ship Movement on Polarimetric Variables at C Band
Authors: Thurai M. , May P. T. , Protat A. 
Published: April 2014

Abstract
The effect of ship motion on shipborne polarimetric radar measurements is considered at C band. Calculations are carried out by (i) varying the “effective” mean canting angle and (ii) separately examining the elevation dependence. Scattering from a single oblate hydrometeor is considered at first. Equations are derived (i) to convert the measured differential reflectivity for nonzero mean canting angles to those for zero mean canting angle and (ii) to do the corresponding corrections for nonzero elevation angles. Scattering calculations are also performed using the T-matrix method with measured drop size distributions as input. Dependence on mean volume diameter is examined as well as variations of the four main polarimetric parameters. The results show that as long as the ship movement is limited to a roll of less than about 10°–15°, the effects are tolerable. Furthermore, the results from the scattering simulations have been used to provide equations for correction factors that can be applied to compensate for the “apparent” nonzero canting angles and nonzero elevation angles, so that drop size distribution parameters and rainfall rates can be estimated without any bias.
Case Study of a Split Front and Associated Precipitation during the Mei-Yu Season
Authors: Geng Biao 
Published: April 2014

Abstract
This study investigated the relationship between a split front and precipitation over western Japan on 10–11 July 2007 based on data from routine observations and a global objective analysis. The split front formed at the leading edge of a dry intrusion overrunning a mei-yu front in a deep layer from the north. Strong upward motion was present ahead of the frontogenesis associated with the split front. In contrast, upward motion over the mei-yu front was suppressed by downward motion behind the split front. An intense rainband developed along the split front south of the mei-yu front. In contrast, precipitation over the mei-yu front gradually disappeared with the southward advance of the split front. Rainfall as heavy as 99 mm h−1 was observed under the rainband associated with the split front. The strong upward motion that induced heavy rains was attributed to the rising branch of the frontal circulation of the split front and the intense low-level convergence facilitated by the dry intrusion behind the split front. These findings indicate that split fronts have a substantial impact on the development and distribution of precipitation during the mei-yu season.
A simple electronic alert for acute kidney injury
Authors: Flynn N , Dawnay A 
Published: April 2014

Background: Acute kidney injury (AKI) is frequently under-recognized and contributes to poor outcomes. Electronic alerts (e-alerts) to highlight AKI based on changes in serum creatinine may facilitate earlier recognition and treatment, and sophisticated algorithms for AKI detection have been proposed or implemented elsewhere. However, many laboratories currently lack the resources or capability to replicate these systems. Methods: A real-time automated delta check e-alert flags a 50% increase in creatinine to a concentration of >50  µmol/L from the most recent result within a 90-day period and automatically adds the comment ‘?AKI – creatinine increase >50% from previous’ with a link to local AKI guidelines. In addition, creatinine results >300  µmol/L are retrospectively reviewed and phoned if AKI is suspected. For each alert over a 12-day period we manually reviewed previous and subsequent creatinine results to determine baseline creatinine and stage AKI according to Acute Kidney Injury Network (AKIN) criteria. Results: From 11,930 creatinine requests, 63 of 90 (70%) delta check e-alerts were due to AKI, identifying 61 episodes of AKI. Thirty four of 54 (63%) creatinine results >300  µmol/L were due to AKI, identifying a further 10 episodes of AKI. The positive predictive value (PPV) for AKI of a delta check e-alert was greater when the trigger creatinine was >100  µmol/L (PPV 89%) or when the absolute change in creatinine was >50  µmol/L (PPV 93%). Conclusion: This study demonstrates that a simple automated delta check can detect and flag AKI in real time, continuously, at little extra cost and without manual input.
Fault tolerant control strategies for a high-rise building hot water heating system
Authors: Lianzhong Li , Zaheeruddin M 
Published: April 2014

Improving energy efficiency and temperature control in hot water heating (HWH) systems are important considerations. The more challenging problem is to maintain good set point control under failure conditions. In this paper, model-based fault detection and diagnosis (FDD) and fault tolerant control (FTC) strategies were designed and simulated for a high-rise building HWH system. An overall system dynamic model with multiple control loops was developed. In the FDD methodology, fuzzy inference systems were employed to isolate the faults and evaluate the fault level. In the FTC strategies, error correcting function was defined consisting of set points, measurement and FDD information. A supply water temperature sensor fault and a multi-fault scenario consisting of heater efficiency fault combined with a partially blocked control valve fault were studied. Simulation runs showed that the developed FDD strategies isolated the faults and the designed FTC strategies were able to improve the system performance. Practical application: The performance of control systems is frequently degraded by the faulty sensors and actuators in hot water heating systems. By implementing the designed fault tolerant control strategies the hot water heating system can be operated to achieve higher energy savings both under fault free and faulty conditions.
Utricular Dysfunction in Refractory Benign Paroxysmal Positional Vertigo
Authors: Angeli Simon I. , Abouyared Marianne , Snapp Hillary , Jethanamest Daniel 
Published: April 2014

ObjectiveTo determine the prevalence of otolith dysfunction in patients with refractory benign paroxysmal positional vertigo (BPPV).Study DesignUnmatched case control.SettingTertiary care institution.Subjects and MethodsPatients included were diagnosed with BPPV, failed initial in‐office canalith repositioning maneuvers (CRMs), and completed vestibular testing and vestibular rehabilitation (n = 40). Refractory BPPV (n = 19) was defined in patients whose symptoms did not resolve despite vestibular rehabilitation. These patients were compared with a control group of those with nonrefractory BPPV (n = 21) for results of a caloric test, cervical vestibular evoked myogenic potential (cVEMP), and subjective visual vertical (SVV).ResultsForty‐six of 251 patients failed initial treatment with in‐office CRM. Forty patients met inclusion criteria. There was no significant difference between the cases (refractory BPPV) (n = 19) and controls (nonrefractory BPPV) (n = 21) in terms of age, duration of symptoms, laterality of BPPV, and BPPV symptoms. There was no difference in the prevalence of caloric weakness and cVEMP abnormalities (P >. 05), with odds ratios (ORs [95% confidence interval (CI)]) of having abnormal results among cases vs controls of 1.1818 (0.3329‐4.1954) and 4.3846 (0.7627‐25.2048), for caloric and cVEMP, respectively. Abnormal eccentric SVV was more prevalent in refractory BPPV cases (58%) than in controls (14%) (P <. 0072). The OR (95% CI) of having abnormal SVV was 8.25 (1.7967‐37.8822) higher among patients with refractory BPPV than those with nonrefractory BPPV.ConclusionPatients with refractory BPPV are more likely to have abnormal eccentric SVV and thus underlying utricular dysfunction. This finding is important to take into account when designing rehabilitation strategies for patients with BPPV who fail CRM.
Effects of 7.5% carbon dioxide inhalation on anxiety and mood in cigarette smokers
Authors: Attwood Angela S , Ataya Alia F , Bailey Jayne E , Lightman Stafford L , Munafò Marcus R 
Published: April 2014

Cigarette smoking is associated with elevated risk of anxiety and mood disorder. Using the 7.5% carbon dioxide (CO2) inhalation model of anxiety induction, we examined the effects of smoking status and abstinence from smoking on anxiety responses. Physiological and subjective responses to CO2 and medical air were compared in smokers and non-smokers (Experiment One) and in overnight abstinent and non-abstinent smokers (Experiment Two). CO2 induced greater increases in blood pressure in non-smokers compared with smokers ( ps < 0.043), and greater increases in anxiety ( p = 0.005) and negative affect ( p = 0.054) in non-abstinent compared with abstinent smokers. CO2 increased physiological and subjective indices of anxiety. There were differences across smoking groups indicating that the CO2 inhalation model is a useful tool for examining the relationship between smoking and anxiety. The findings suggested that both acute smoking and acute abstinence may protect against anxious responding. Further investigation is needed in long-term heavy smokers.
Allodynia is associated with a higher prevalence of depression in migraine patients
Authors: Louter MA , Wardenaar KJ , Veen G , van Oosterhout WPJ , Zitman FG , Ferrari MD , Terwindt GM 
Published: April 2014

Introduction There is a strong association between migraine and depression. The aim of this study is to identify migraine-specific factors involved in this association. Methods We conducted a cross-sectional study in a large, well-defined cohort of migraine patients ( n = 2533). We assessed lifetime depression using validated questionnaires, and diagnosed migraine based on the International Classification of Headache Disorders III-beta criteria. Multivariate regression analyses were conducted. Results Of the 2533 migraineurs that were eligible, 1137 (45%) suffered from lifetime depression. The following independent factors were associated with an increased depression prevalence: i) migraine-specific risk factors: high migraine attack frequency and the presence of allodynia, ii) general factors: being a bad sleeper, female gender, high BMI, being single, smoking, and a low alcohol consumption. Conclusion This study identified allodynia, in addition to high migraine attack frequency, as a new migraine-specific factor associated with depression.
Arthroscopic Iliopsoas Fractional Lengthening for Internal Snapping of the Hip
Authors: El Bitar Youssef F. , Stake Christine E. , Dunne Kevin F. , Botser Itamar B. , Domb Benjamin G. 
Published: April 2014

Background: Internal snapping of the hip is caused by the iliopsoas (IP) tendon sliding over the iliopectineal eminence or the femoral head. In many cases that require hip arthroscopic surgery, there is coexistent painful internal snapping. In such cases, fractional lengthening of the IP tendon has been suggested as an adjunctive procedure. Purpose: To examine the outcomes and effectiveness of arthroscopic IP tendon fractional lengthening as a solution to coexistent internal hip snapping in patients undergoing hip arthroscopic surgery for a labral tear and/or femoroacetabular impingement. Study Design: Case series; Level of evidence, 4. Methods: Between June 2010 and June 2011, data were prospectively collected for all patients with internal snapping of the hip who underwent primary arthroscopic IP tendon fractional lengthening, with a minimum 2-year follow-up. All patients were interviewed by telephone with specific questions regarding the resolution or persistence of snapping. Patients were assessed preoperatively and postoperatively using the following patient-reported outcome (PRO) measures: Non-Arthritic Hip Score (NAHS), Hip Outcome Score–Activity of Daily Living (HOS-ADL) and Sport-Specific Subscale (HOS-SSS), and modified Harris Hip Score (mHHS). Pain was recorded on a visual analog scale (VAS), and satisfaction was measured on a scale from 0 to 10. Results: A total of 55 patients were included, with all PROs showing statistically significant improvement postoperatively (NAHS: 57.6 ± 20.6 preoperatively vs 80.2 ± 19.2 at 2 years; HOS-ADL: 60.9 ± 21.4 preoperatively vs 81.8 ± 20.6 at 2 years; HOS-SSS: 43.4 ± 24.6 preoperatively vs 70.0 ± 26.7 at 2 years; and mHHS: 62.3 ± 16.4 preoperatively vs 80.5 ± 18.3 at 2 years) ( P < .001 for all). Forty-five patients (81.8%) reported good/excellent satisfaction (≥7). Overall, 45 patients (81.8%) reported resolution of painful snapping. Patients who had resolution of snapping had statistically significant superior outcomes compared with those with persistent snapping using the change in the NAHS value (25.8 ± 16.1 vs 8.0 ± 22.5, respectively; P = .005), change in the HOS-ADL value (23.6 ± 18.0 vs 8.5 ± 15.2, respectively; P = .017), change in the HOS-SSS value (30.7 ± 26.9 vs 8.7 ± 23.6, respectively; P = .021), and change in the mHHS value (23.3 ± 20.1 vs 4.4 ± 9.9, respectively; P = .005). Conclusion: A majority of patients reported resolution of painful snapping and improvement in symptoms. Nonetheless, the rate of persistence of internal snapping at a minimum 2 years postoperatively was higher than that reported in previous studies.
Simultaneous Reconstruction of the Anterior Cruciate Ligament and Medial Collateral Ligament in Patients With Chronic ACL-MCL Lesions
Authors: Zhang Hangzhou , Sun Yu , Han Xiaorui , Wang Yanfeng , Wang Lin , Alquhali Ali , Bai Xizhuang 
Published: April 2014

Background: In cases of chronic anterior cruciate ligament (ACL)–medial collateral ligament (MCL) lesions, nonoperative treatment of the MCL lesion may lead to chronic valgus instability and rotatory instability. The optimal management for patients who have combined ACL-MCL injuries remains controversial. Purpose: To present a case series of 21 patients who underwent simultaneous ACL-MCL reconstruction with a 2- to 5-year follow-up. Study Design: Case series; Level of evidence, 4. Methods: From October 2007 to December 2010, a total of 21 patients with chronic ACL-MCL injuries, for which the 2 ligaments were reconstructed during the same surgical procedure, were studied. All patients were available for follow-up for at least 2 years. The International Knee Documentation Committee (IKDC) subjective knee scores, valgus and sagittal stability, anteromedial rotatory stability, range of motion, and complications were assessed both preoperatively and postoperatively. Results: At follow-up, valgus and sagittal laxity were not observed in any of the patients. The mean medial knee opening was significantly reduced to 0.80 ± 0.96 mm (range, –1.2 to 2.6 mm) postoperatively compared with 8.0 ± 1.3 mm (range, 6.1 to 10.7 mm) preoperatively ( P < .01). The mean postoperative side-to-side difference measured with the KT-1000 arthrometer was reduced to 0.8 ± 0.9 mm (range, –1.2 to 2.3 mm) compared with 8.4 ± 1.6 mm (range, 6.2 to 13.2 mm) preoperatively ( P < .01). Preoperative anteromedial instability was seen in 71% of patients (15/21), whereas none of the patients had anteromedial rotatory instability at the last follow-up. The mean IKDC subjective score improved overall from 45.3 ± 12.0 (range, 28.7-69.0) preoperatively to 87.7 ± 8.2 (range, 65.5-100.0) at the last follow-up ( P < .01). Most patients (20/21) had normal or nearly normal range of motion of the knee joint; only 1 patient (5%) had a limitation of flexion of 15° compared with the contralateral knee at the last follow-up. Conclusion: In patients with chronic ACL-MCL lesions, simultaneous reconstruction of the ACL and MCL can significantly improve the medial, sagittal, and rotatory stability of the knee at short-term follow-up.
Validation of the 10/66 Dementia Research Group Diagnostic Assessment for Dementia in Arabic
Authors: Phung Kieu T. T. , Chaaya Monique , Waldemar Gunhild , Atweh Samir , Asmar Khalil , Ghusn Husam , Karam Georges , Sawaya Raja , Khoury Rose Mary , Zeinaty Ibrahim , Salman Sandrine , Hammoud Salem , Radwan Wael , Bassil Nazem , Prince Martin 
Published: April 2014

Objectives: In the North Africa and Middle East region, the illiteracy rates among older people are high, posing a great challenge to cognitive assessment. Validated diagnostic instruments for dementia in Arabic are lacking, hampering the development of dementia research in the region. The study aimed at validating the Arabic version of the 10/66 Dementia Research Group (DRG) diagnostic assessment for dementia to determine whether it is suitable for case ascertainment in epidemiological research. Methods: A total of 244 participants older than 65 years were included, 100 with normal cognition and 144 with mild to moderate dementia. Dementia was diagnosed by clinicians according to Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria. Depression was diagnosed using the Geriatric Mental State. Trained interviewers blind to the cognitive status of the participants administered the 10/66 DRG diagnostic assessment to the participants and interviewed the caregivers. The discriminatory ability of the 10/66 DRG assessment and its subcomponents were evaluated against the clinical diagnoses. Results: Half of the participants had no formal education and 49% of them were depressed. The 10/66 DRG diagnostic assessment showed excellent sensitivity (92.0%), specificity (95.1%), positive predictive value (PPV, 92.9%), and low false-positive rates among controls with no formal education (8.1%) and depression (5.6%). Each subcomponent of the 10/66 DRG diagnostic assessment independently predicted dementia diagnosis. The predictive ability of the 10/66 DRG assessment was superior to that of its subcomponents. Conclusion: The 10/66 DRG diagnostic assessment for dementia is well suited for case ascertainment in epidemiological studies among Arabic-speaking older population with high prevalence of illiteracy.