bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Mechanical Energy Input to the Ocean Induced by Tropical Cyclones
Authors: Liu Ling Ling , Wang Wei , Huang Rui Xin 
Published: June 2008

Abstract
Wind stress and tidal dissipation are the most important sources of mechanical energy for maintaining the oceanic general circulation. The contribution of mechanical energy due to tropical cyclones can be a vitally important factor in regulating the oceanic general circulation and its variability. However, previous estimates of wind stress energy input were based on low-resolution wind stress data in which strong nonlinear events, such as tropical cyclones, were smoothed out.
Using a hurricane–ocean coupled model constructed from an axisymmetric hurricane model and a three-layer ocean model, the rate of energy input to the world’s oceans induced by tropical cyclones over the period from 1984 to 2003 was estimated. The energy input is estimated as follows: 1.62 TW to the surface waves and 0.10 TW to the surface currents (including 0.03 TW to the near-inertial motions). The rate of gravitational potential energy increase due to tropical cyclones is 0.05 TW. Both the energy input from tropical cyclones and the increase of gravitational potential energy of the ocean show strong interannual and decadal variability with an increasing rate of 16% over the past 20 years. The annual mean diapycnal upwelling induced by tropical cyclones over the past 20 years is estimated as 39 Sv (Sv ≡ 106 m3 s−1). Owing to tropical cyclones, diapycnal mixing in the upper ocean (below the mixed layer) is greatly enhanced. Within the regimes of strong activity of tropical cyclones, the increase of diapycnal diffusivity is on the order of (1 − 6) × 10−4 m2 s−1. The tropical cyclone–related energy input and diapycnal mixing may play an important role in climate variability, ecology, fishery, and environments.
Parameterization of Mixed Layer Eddies. Part II: Prognosis and Impact
Authors: Fox-Kemper Baylor , Ferrari Raffaele 
Published: June 2008

Abstract
The authors propose a parameterization for restratification by mixed layer eddies that develop from baroclinic instabilities of ocean fronts. The parameterization is cast as an overturning streamfunction that is proportional to the product of horizontal buoyancy gradient, mixed layer depth, and inertial period. The parameterization has remarkable skill for an extremely wide range of mixed layer depths, rotation rates, and vertical and horizontal stratifications. In this paper a coarse resolution prognostic model of the parameterization is compared with submesoscale mixed layer eddy resolving simulations. The parameterization proves accurate in predicting changes to the buoyancy. The climate implications of the proposed parameterization are estimated by applying the restratification scaling to observations: the mixed layer depth is estimated from climatology, and the buoyancy gradients are from satellite altimetry. The vertical fluxes are comparable to monthly mean air–sea fluxes in large areas of the ocean and suggest that restratification by mixed layer eddies is a leading order process in the upper ocean. Critical regions for ocean–atmosphere interaction, such as deep, intermediate, and mode water formation sites, are particularly affected.
Parameterization of Mixed Layer Eddies. Part I: Theory and Diagnosis
Authors: Fox-Kemper Baylor , Ferrari Raffaele , Hallberg Robert 
Published: June 2008

AbstractAgeostrophic baroclinic instabilities develop within the surface mixed layer of the ocean at horizontal fronts and efficiently restratify the upper ocean. In this paper a parameterization for the restratification driven by finite-amplitude baroclinic instabilities of the mixed layer is proposed in terms of an overturning streamfunction that tilts isopycnals from the vertical to the horizontal. The streamfunction is proportional to the product of the horizontal density gradient, the mixed layer depth squared, and the inertial period. Hence restratification proceeds faster at strong fronts in deep mixed layers with a weak latitude dependence. In this paper the parameterization is theoretically motivated, confirmed to perform well for a wide range of mixed layer depths, rotation rates, and vertical and horizontal stratifications. It is shown to be superior to alternative extant parameterizations of baroclinic instability for the problem of mixed layer restratification. Two companion papers discuss the numerical implementation and the climate impacts of this parameterization.
On the Weakly Nonlinear Ekman Layer: Thickness and Flux
Authors: Pedlosky Joseph 
Published: June 2008

Abstract
The first-order effects of nonlinearity on the thickness and frictionally driven flux in the Ekman layer are described for the case of an Ekman layer on a solid, flat plate driven by an overlying geostrophic flow as well as the Ekman layer on a free surface driven by a wind stress in the presence of a deep geostrophic current. In both examples, the fluid is homogeneous. Particular attention is paid to the effect of nonlinearity in determining the thickness of the Ekman layer in both cases. An analytical expression for the Ekman layer thickness as a function of Rossby number is given when the Rossby number is small. The result is obtained by insisting that the perturbation expansion of the Ekman problem in powers of the Rossby number remains uniformly valid. There are two competing physical effects. The relative vorticity of the geostrophic currents tends to reduce the width of the layer, but the vertical velocity induced in the layer can fatten or thin the layer depending on the sign of the vertical velocity. The regularized expansion is shown to give, to lowest order, expressions for the flux in agreement with earlier calculations.
Gyres and Jets: Inversion of Tracer Data for Ocean Circulation Structure
Authors: Herbei Radu , McKeague Ian W. , Speer Kevin G. 
Published: June 2008

Abstract
This paper describes a quasi-3D Bayesian inversion of oceanographic tracer data from the South Atlantic Ocean. Initially, one active neutral-density layer is considered with an upper and lower boundary. The available hydrographic data are linked to model parameters (water velocities, diffusion coefficients) via a 3D advection–diffusion equation. A robust solution to the inverse problem can be obtained by introducing prior information about parameters and modeling the observation error. This approach estimates both horizontal and vertical flow as well as diffusion coefficients. A system of alternating zonal jets is found at the depths of the North Atlantic Deep Water, consistent with direct measurements of flow and concentration maps. A uniqueness analysis of the model is performed in terms of the oxygen consumption rate. The vertical mixing coefficient bears some relation to the bottom topography even though the authors do not incorporate topography into their model. The method is extended to a multilayer model, using thermal wind relations weakly in a local fashion (as opposed to integrating the entire water column) to connect layers vertically. Results suggest that the estimated deep zonal jets extend vertically, with a clear depth-dependent structure. The vertical structure of the flow field is modified by the tracer fields relative to the a priori flow field defined by thermal wind. The velocity estimates are consistent with independent observed flow at the depths of the Antarctic Intermediate Water; at still shallower depths, above the layers considered here, the subtropical gyre is a significant feature of the horizontal flow.
Improvement of hand dexterity following motor cortex rTMS in multiple sclerosis patients with cerebellar impairment
Authors: Koch G , Rossi S , Prosperetti C , Codecà C , Monteleone F , Petrosini L , Bernardi G , Centonze D 
Published: June 2008

We tested the effects of 5-Hz repetitive transcranial magnetic stimulation (rTMS) over the motor cortex in multiple sclerosis (MS) subjects with cerebellar symptoms. rTMS improved hand dexterity in cerebellar patients ( n = 8) but not in healthy subjects ( n = 7), as detected by a significant transient reduction of the time required to complete the nine-hole pegboard task. rTMS of the motor cortex may be a useful approach to treat cerebellar impairment in MS patients.
Autoimmune diseases in patients with multiple sclerosis and their first-degree relatives: a nationwide cohort study in Denmark
Authors: Nielsen NM , Frisch M , Rostgaard K , Wohlfahrt J , Hjalgrim H , Koch-Henriksen N , Melbye M , Westergaard T 
Published: June 2008

Background Multiple sclerosis (MS) and other autoimmune diseases might cluster. Our aim was to estimate the relative risk (RR) of other autoimmune diseases among MS patients and their first-degree relatives in a population-based cohort study. Methods Using the Danish Multiple Sclerosis Register, the Danish Hospital Discharge Register, and the Danish Civil Registration System, we estimated RRs for 42 different autoimmune diseases in a population-based cohort of 12 403 MS patients and 20 798 of their first-degree relatives. Ratios of observed to expected numbers of autoimmune diseases, based on national sex-, age-, and period-specific incidence rates, served as measures of the RRs. Results Compared with the general population, MS patients were at an increased risk of developing ulcerative colitis (RR = 2.0 (95% confidence interval (CI): 1.4–2.8), n = 29) and pemphigoid (RR = 15.4 (CI: 8.7–27.1), n = 12) but at reduced risk of rheumatoid arthritis (RR = 0.5 (CI: 0.4–0.8), n = 28) and temporal arteritis (RR = 0.5 (CI: 0.3–0.97), n = 11). First-degree relatives of MS patients were at increased risks of Crohn’s disease (RR = 1.4 (CI: 1.04–1.9), n = 44), ulcerative colitis (RR = 1.3 (CI: 0.99–1.7), n = 51), Addison’s disease (RR = 3.4 (CI: 1.3–9.0), n = 4), and polyarteritis nodosa (RR = 3.7 (CI: 1.4–10.0), n = 4). Conclusion Patients with MS and their first-degree relatives seem to be at an increased risk of acquiring certain other autoimmune diseases.
Factors associated with the risk of secondary progression in multiple sclerosis
Authors: Koch M , Uyttenboogaart M , van Harten A , De Keyser J 
Published: June 2008

Objective To investigate factors associated with the risk of secondary progression in relapsing-remitting onset multiple sclerosis (MS). Methods We used Kaplan-Meier survival analyses and a multivariable Cox regression model to estimate the influence of the factors: gender, age at disease onset, use of immunomodulatory drugs (IMD), and clinical manifestation at disease onset on the time to secondary progression in a hospital-based cohort of 571 MS patients with a relapsing-remitting onset. Results Gender and onset manifestation had no significant influence on the timing of secondary progression. A higher age at disease onset was associated with a shorter time to secondary progression (multivariable hazard ratio per year increase: 1.02, 95% CI:1.01 - 1.03). The use of IMD was associated with a longer time to secondary progression (multivariable hazard ratio: 0.30, 95% CI: 0.15 - 0.61). Conclusions The inverse relationship between age at disease onset and onset of secondary progression is in keeping with previous natural history studies. The beneficial effect of IMD treatment on the time to secondary progression should be taken as hypothesis-generating rather than as proof of a treatment effect, and needs to be further evaluated in well-designed randomised controlled trials.
Memory decline evolves independently of disease activity in MS
Authors: Duque B , Sepulcre J , Bejarano B , Samaranch L , Pastor P , Villoslada P 
Published: June 2008

Background The natural history of cognitive impairment in multiple sclerosis (MS) and its relationship with disease activity is not well known. In this study, we evaluate a prospective cohort of 44 MS patients who were followed every 3 months for 2 years. Cognitive evaluation was done at baseline and by the end of the study using the Brief Repeatable Battery-Neuropsychology. Clinical evaluation included assessment of new relapses and changes in disability (Extended Disability Status Scale (EDSS)) confirmed at 6 months. Results We found that verbal memory performance deteriorates after 2 years in patients with MS. These changes were observed in stable and active patients both in terms of relapses and disability progression, even at the beginning of the disease, and in patients with or without cognitive impairment at study entry. Attention and executive functions measured with the symbol digit modality test (SDMT) declined after 2 years in patients with confirmed disability progression. Furthermore, SDMT performance correlated with the EDSS change. Conclusions Our findings indicate that verbal memory steadily declines in patients with MS from the beginning of the disease and independently of other parameters of disease activity.
Retinal nerve fiber layer atrophy is associated with physical and cognitive disability in multiple sclerosis
Authors: Toledo J , Sepulcre J , Salinas-Alaman A , García-Layana A , Murie-Fernandez M , Bejarano B , Villoslada P 
Published: June 2008

Background Studying axonal loss in the retina is a promising biomarker for multiple sclerosis (MS). Our aim was to compare optical coherence tomography (OCT) and Heidelberg retinal tomography (HRT) techniques to measure the thickness of the retinal nerve fiber layer (RNFL) in patients with MS, and to explore the relationship between changes in the RNFL thickness with physical and cognitive disability. We studied 52 patients with MS and 18 proportionally matched controls by performing neurological examination, neuropsychological evaluation using the Brief Repetitive Battery-Neuropsychology and RNFL thickness measurement using OCT and HRT. Results We found that both OCT and HRT could define a reduction in the thickness of the RNFL in patients with MS compared with controls, although both measurements were weakly correlated, suggesting that they might measure different aspects of the tissue changes in MS. The degree of RNFL atrophy was correlated with cognitive disability, mainly with the symbol digit modality test ( r = 0.754, P < 0.001). Moreover, temporal quadrant RNFL atrophy measured with OCT was associated with physical disability. Conclusion In summary, both OCT and HRT are able to detect thinning of the RNFL, but OCT seems to be the most sensitive technique to identify changes associated with MS evolution.
Patients with multiple sclerosis resisted to glucocorticoid therapy: abnormal expression of heat-shock protein 90 in glucocorticoid receptor complex
Authors: Matysiak M , Makosa B , Walczak A , Selmaj K 
Published: June 2008

Objective The majority of patients with multiple sclerosis (MS) respond favorably to glucocorticoids (GS) for their relapse treatment (steroid-sensitive multiple sclerosis). Unfortunately, a small subset of patients with multiple-sclerosis fails to adequately respond even to high dose of GS (steroid-resistant multiple sclerosis). Mechanism of GS therapeutic unresponsiveness is not resolved. Methods Transcripts for glucocorticoid receptor (GR) was assessed in peripheral blood mononuclear cells by real-time polymerase chain reaction in patients with steroid-sensitive and steroid-resistant multiple sclerosis. GR expression was assessed by Western blotting. The amount of heat-shock protein 90 (hsp90) in GR cytoplasmic complex was assessed by immunoprecipitation. Hsp90 was shown to stabilize the GR complex, to prevent its translocation to nucleus, and to inhibit GR transcription. Results Peripheral blood mononuclear cells of steroid-resistant multiple sclerosis transcripts for all three isoforms of GR, α, β, and γ, were reduced by about two-folds compared with patients with steroid-sensitive multiple sclerosis. We have not found an increase in the β and γ transcripts of GR, which might serve as a dominant negative mutants, over GR α in steroid-resistant multiple sclerosis. The amount of hsp90 in the GR complex in cytoplasm was significantly higher in steroid-resistant multiple sclerosis compared with steroid-sensitive multiple sclerosis. Conclusions Molecular mechanism of GS unresponsiveness in some patients with multiple sclerosis might be related to increased presence of hsp90 in the GR cytoplasmic complex, leading to the inhibition of GR translocation to nucleus and reduction in its transcription.
Cognitive dysfunction 24–31 years after isolated optic neuritis
Authors: Nilsson P , Rorsman I , Larsson EM , Norrving B , Sandberg-Wollheim M 
Published: June 2008

Objective Cognitive dysfunction is common in multiple sclerosis (MS), but long-term data on cognition in patients with clinically isolated syndromes are sparse. Methods We determined cognitive functions in 22 patients 44–75 years old diagnosed with optic neuritis 24–31 years earlier but had no further clinical bouts and had not progressed clinically to MS. We used a neuropsychological test battery covering nine cognitive domains. Magnetic resonance imaging (MRI) of the brain had been performed earlier and was normal in six patients and showed two or more white matter abnormalities compatible with demyelinating lesions in 16 patients. Results On neuropsychological testing, one patient was within normal range on all tests, six subjects showed borderline results, and 15 patients (68%) showed significantly impaired performance in at least one cognitive domain. Seven patients showed significant impairment in two or more domains. Executive function, visuo-spatial ability, and information processing speed were the most frequently affected domains. There was no apparent correlation between MRI findings and cognitive function. Conclusions We conclude that cognitive dysfunction is common in patients many years after clinically isolated optic neuritis. Cognitive dysfunction was found even in patients who had no apparent demyelinating lesions on follow-up MRI.
Long-term follow-up of suspected though unconfirmed MS
Authors: Nielsen JM , Uitdehaag BMJ , Polman CH 
Published: June 2008

Objective There is no gold standard diagnostic test for MS, and evaluation of present diagnostic criteria has almost exclusively been done in populations of which the vast majority is prone to develop MS. Patients referred for a potential MS diagnosis in whom ultimately another or no diagnosis is made are seldomly reported in a systematic way. We report, after 7 years, on the diagnoses made in a cohort of patients with suspected though unconfirmed MS. Methods We retrieved information on the current diagnosis of all patients who had visited our center between 1998 and 2001 for a second opinion concerning a possible MS diagnosis and in whom no diagnosis had been made at that time. Results Seventy-five patients (86%) could be retrieved and cooperated. In seven patients, a diagnosis of MS, in eight patients another neurological diagnosis had been made. In the remaining 60 patients, still no neurological diagnosis had been made. Conclusions In potential MS patients seen in a tertiary referral center, the likelihood that a patient who is not diagnosed with MS will in the future develop a neurological disease is small. This study suggests that, in addition to playing a role in diagnosing MS, MRI can be helpful to exclude MS in clinically doubtful cases.
Tracking retinal nerve fiber layer loss after optic neuritis: a prospective study using optical coherence tomography
Authors: Costello F , Hodge W , Pan YI , Eggenberger E , Coupland S , Kardon RH 
Published: June 2008

Introduction Optic neuritis causes retinal nerve fiber layer damage, which can be quantified with optical coherence tomography. Optical coherence tomography may be used to track nerve fiber layer changes and to establish a time-dependent relationship between retinal nerve fiber layer thickness and visual function after optic neuritis. Methods This prospective case series included 78 patients with optic neuritis, who underwent optical coherence tomography and visual testing over a mean period of 28 months. The main outcome measures included comparing inter-eye differences in retinal nerve fiber layer thickness between clinically affected and non-affected eyes over time; establishing when RNFL thinning stabilized after optic neuritis; and correlating retinal nerve fiber layer thickness and visual function. Results The earliest significant inter-eye differences manifested 2-months after optic neuritis, in the temporal retinal nerve fiber layer. Inter-eye comparisons revealed significant retinal nerve fiber layer thinning in clinically affected eyes, which persisted for greater than 24 months. Retinal nerve fiber thinning manifested within 6 months and then stabilized from 7 to 12 months after optic neuritis. Regression analyses demonstrated a threshold of nerve fiber layer thickness (75μm), which predicted visual recovery after optic neuritis. Conclusions Retinal nerve fiber layer changes may be tracked and correlated with visual function within 12 months of an optic neuritis event.
Atorvastatin decreases high-sensitivity C-reactive protein in multiple sclerosis
Authors: Sellner J , Greeve I , Mattle HP 
Published: June 2008

The anti-inflammatory potential of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, as reflected by modulation of C-reactive protein (CRP), might be beneficial in the treatment of patients with multiple sclerosis (MS). We evaluated serum levels of high-sensitivity (hs)-CRP in relapsing–remitting MS patients receiving interferon-β 1b and atorvastatin as add-on therapy. This study shows that interferon-β treatment is associated with increased serum levels of hs-CRP in MS patients ( P < 0.01). In contrast, when atorvastatin is added to interferon-β, hs-CRP serum levels decrease to the normal range ( P < 0.05), indicating an anti-inflammatory action of atorvastatin in MS. However, whether add-on treatment with atorvastatin modifies the course of MS remains to be investigated.
Impact of disease-modifying treatments in North African migrants with multiple sclerosis in France
Authors: Lebrun C , Debouverie M , Jeannin S , Pittion-Vouyovitch S , Bayreuther C , Berthier F 
Published: June 2008

Background Multiple Sclerosis in North African migrants (MS-NA) is more aggressive with mostly primary progressive forms and cerebellar symptoms. Despite an earlier onset in NA patients, the disease progresses more rapidly, with a higher proportion showing incomplete recovery from the first relapse, a shorter time between the first two relapses, a higher number of relapses in the first 5 years, and a shorter time to reach an EDSS of 4.0 and 6.0. We collected data and studied the impact of disease-modifying therapies (DMT) in NA patients with MS, among the 4144 MS patients treated in our MS clinics. Methods We performed a descriptive population-based study of MS-NA patients. Data were crossed with expected age- and gender-matched characteristics available in our EDMUS databases for the period 1995–2007. Results A total of 133 patients, representing 66% of the MS-NA patients included in the database were identified: mean age at the first documented symptom: 29.7 years; mean time from diagnosis to the beginning of DMT: 1.2 years. 40% of MS-NA patients had an EDSS >3 at the beginning of treatment (vs. 25%; P = 0.002). A majority of patients were treated initially with immunomodulatory drugs (MS-NA: 48% vs. CT: 51%, P = 0.8). NA patients were treated earlier after diagnosis (1.3 years vs. 4.5 years, P = 0.003), with the frequent use of immunosuppressive drugs: for remitting forms, mitoxantrone (18.5% vs. 7.8%, P = 0.0001) and for progressive forms, cyclophosphamide (38% vs. 28%, P = 0.003). Conclusions Considering EDSS follow-up during DMT, MS-NA patients appear as responsive as other MS patients to treatment, despite the earlier treatment prescription and the more frequent use of immunosuppressors.