2,366 research outputs found
On uniqueness and non-uniqueness for current reconstruction from magnetic fields
No full textThe goal of this paper is to provide a basis for the analysis of the limits of the reconstructability of current densities from their magnetic fields as used for non-destructive testing and monitoring of fuel cells. For the reconstruction of a current density from its magnetic field, we study the properties of the Biot-Savart operator W. In particular, the nullspace N(W) of the Biot-Savart operator and its orthogonal space N(W)(perpendicular to) with respect to the L-2 scalar product are characterized. The characterization of these spaces is a basic step for the evaluation of the principal limits of magnetic tomography for fuel cells and for the development of efficient reconstruction algorithms. Further, practically realizable examples for elements in the nullspace N(W) are provided. Finally, for a discrete wire network we show uniqueness for current reconstructions, i.e. the result N(W) = {0}
Glucocorticoid-endocannabinoid interaction in cardiac surgical patients: relationship to early cognitive dysfunction and late depression
No full textBackground: Endocannabinoids (ECs) are rapidly acting immune-modulatory lipid-signaling molecules that are important for adaptation to stressful and aversive situations. They are known to interact with glucocorticoids and other stress-responsive systems. Maladaptation to acute or chronic stress represents a major risk factor for the development of psychiatric disorders. In the present study, we administered stress doses of hydrocortisone in a prospective, randomized, placebo-controlled double-blind study in patients undergoing cardiac surgery (CS) to examine the relationship between the use of glucocorticoids, plasma EC levels, and the occurrence of early postoperative cognitive dysfunction (delirium) and of later development of depression. Methods: We determined plasma levels of the ECs anandamide and 2-arachidonoylglycerol (2-AG) in CS patients of the hydrocortisone (n=56) and the placebo group (n=55) preoperatively, at postoperative day (POD) 1, at intensive care unit discharge, and at 6 months after CS (n=68). Postoperative delirium was diagnosed according to Diagnostic and Statistical Manual of the American Psychiatric Association IVth Edition (DSM-IV) criteria, and depression was determined by validated questionnaires and a standardized psychological interview (Structured Clinical Interview for DSM-IV). Results: Stress doses of hydrocortisone did not affect plasma EC levels and the occurrence of delirium or depression. However, patients who developed delirium on POD 1 had significantly lower preoperative 2-AG levels of the neuroprotective EC 2-AG (median values, 3.8 vs. 11.3 ng/ml; p=0.03). Preoperative 2-AG concentrations were predictive of postoperative delirium (sensitivity=0.70; specificity=0.69; cutoff value=4.9 ng/ml; receiver operating characteristic curve area=0.70; 95% confidence interval=0.54-0.85). Patients with depression at 6 months after CS (n=16) had significantly lower anandamide and 2-AG levels during the perioperative period. Conclusions: A low perioperative EC response may indicate an increased risk for early cognitive dysfunction and long-term depression in patients after CS. Glucocorticoids do not seem to influence this relationship
Teitelbaum's exceptional zero conjecture in the function field case
No full textThe exceptional zero conjecture relates the first derivative of the p-adic L-function of a rational elliptic curve with split multiplicative reduction at p to its complex L-function. Teitelbaum formulated an analogue of Mazur and Tate's refined (multiplicative) version of this conjecture for elliptic curves over the rational function field q(T) with split multiplicative reduction at two places and ∞, avoiding the construction of a -adic L-function. This article proves Teitelbaum's conjecture up to roots of unity by developing Darmon's theory of double integrals over arbitrary function fields. A function field version of Darmon's period conjecture is also obtained
Ryhiner-Kartensammlung / 23 Sevilla regnum : in suas archiepiscopatos episcopatos et praefecturas divisum = Carte de Sevilla
No full textper Franciscum Ellobet et Thom. Lopez delineatum, aliisque subsidiis emendatum à F.L. Güssefeld ; denuo per Homan[n]ianos Heredes editum ; Hauer sc. Nor."C.P.S.C.M."Nullmeridian: Isla del Hierro (Ferro
Ryhiner-Kartensammlung / 23 Sevilla regnum : in suas archiepiscopatos episcopatos et praefecturas divisum = Carte de Sevilla
No full textper Franciscum Ellobet et Thom. Lopez delineatum, aliisque subsidiis emendatum a F.L. Güssefeld. ; denuo per Homan[n]ianos Heredes editum ; Hauer sc. Nor."C.P.S.C.M."Titel oberhalb der Karte: "Carte de Sevilla."Nullmeridian: Isla del Hierro (Ferro
Ryhiner-Kartensammlung / 20 Sevilla regnum : in suos archiepiscopatos episcopatos et praefecturas divisum = Carte de Sevilla
No full textper Franciscum Ellobet et Thom. Lopez delineatum, aliisque subsidiis emendatum à F.L. Güssefeld ; denuo per Homan[n]ianos Heredes editum ; Hauer sc. Nor."C.P.S.C.M."Nullmeridian: Isla del Hierro (Ferro
Endocannabinoids in the rat basolateral amygdala enhance memory consolidation and enable glucocorticoid modulation of memory
No full textExtensive evidence indicates that the basolateral complex of the amygdala (BLA) modulates the consolidation of memories for emotionally arousing experiences, an effect that involves the activation of the glucocorticoid system. Because the BLA expresses high densities of cannabinoid CB1 receptors, the present experiments investigated whether the endocannabinoid system in the BLA influences memory consolidation and whether glucocorticoids interact with this system. The CB1 receptor agonist WIN55,212-2 (5-50 ng per 0.2 mu L per side), infused bilaterally into the BLA of male Sprague-Dawley rats immediately after inhibitory avoidance training, induced dose-dependent enhancement of 48-h retention. Conversely, the CB1 receptor antagonist AM251 (0.07-0.28 ng per 0.2 mu L per side) administered after training into the BLA induced inhibitory avoidance retention impairment. Furthermore, intra-BLA infusions of a low and nonimpairing dose of AM251 (0.14 ng per 0.2 mu L per side) blocked the memory enhancement induced by concurrent administration of WIN55,212-2. Delayed infusions of WIN55,212-2 or AM251 administered into the BLA 3 h after training or immediate posttraining infusions of these drugs into the adjacent central amygdala did not significantly alter retention performance. Last, intra-BLA infusions of a low and otherwise nonimpairing dose of AM251 (0.14 ng per 0.2 mu L per side) blocked the memory-enhancing effect induced by systemic administration of corticosterone (3 mg/kg, s.c.). These findings indicate that endo-cannabinoids in the BLA enhance memory consolidation and suggest that CB1 activity within this brain region is required for enabling glucocorticoid effects on memory consolidation enhancement
Development and initial validation of the Falls Efficacy Scale International (FES-I).
No full textBackground: there is a need for a measure of fear of falling that assesses both easy and difficult physical activities and social activities and is suitable for use in a range of languages and cultural contexts, permitting direct comparison between studies and populations in different countries and settings. Objective: to develop a modified version of the Falls Efficacy Scale to satisfy this need, and to establish its psychometric properties, reliability, and concurrent validity (i.e. that it demonstrates the expected relationship with age, falls history and falls risk factors). Design: cross-sectional survey. Setting: community sample. Method: 704 people aged between 60 and 95 years completed The Falls Efficacy Scale-International (FES-I) either in postal self-completion format or by structured interview. Results: the FES-I had excellent internal and test–retest reliability (Cronbach’s =0.96, ICC=0.96). Factor analysis suggested a unitary underlying factor, with two dimensions assessing concern about less demanding physical activities mainly in the home, and concern about more demanding physical activities mainly outside the home. The FES-I had slightly better power than the original FES items to discriminate differences in concern about falling between groups differentiated by sex, age, occupation, falls in the past year, and falls risk factors (chronic illness, taking multiple or psychoactive medications, dizziness). Conclusions: the FES-I has close continuity with the best existing measure of fear of falling, excellent psychometric properties, and assesses concerns relating to basic and more demanding activities, both physical and social. Further research is required to confirm cross-cultural and predictive validity
Enhanced Anandamide Plasma Levels in Patients with Complex Regional Pain Syndrome following Traumatic Injury: A Preliminary Report
No full textThe complex regional pain syndrome (CRPS) is a disabling neuropathic pain condition that may develop following injuries of the extremities. The pathogenesis of this syndrome is not clear; however, it includes complex interactions between the nervous and the immune system resulting in chronic inflammation, pain and trophic changes. This interaction may be mediated by chronic stress which is thought to activate the endogenous cannabinoid (endocannabinoid) system (ECS). We conducted an open, prospective, comparative clinical study to determine plasma level of the endocannabinoid anandamide by high-performance liquid chromatography and a tandem mass spectrometry system in 10 patients with CRPS type I versus 10 age- and sex-matched healthy controls. As compared to healthy controls, CRPS patients showed significantly higher plasma concentrations of anandamide. These results indicate that the peripheral ECS is activated in CRPS. Further studies are warranted to evaluate the role of the ECS in the limitation of inflammation and pain. Copyright (C) 2009 S. Karger AG, Base
Water use efficiency of sugar beet cultivars (Beta vulgaris L.) susceptible, tolerant or resistant to Heterodera schachtii (Schmidt) in environments with contrasting infestation levels
No full textHeterodera schachtii is an important pest in many European sugar beet growing regions. Yield response to H. schachtii can be highly variable depending on the infestation level, soil properties, weather conditions and the cultivar. This study aimed at evaluating the effects of nematode infestation on sugar and dry matter yield, crop evapotranspiration (ETc) and water use efficiency (WUE) of cultivars being susceptible, tolerant or resistant to H. schachtii. Field experiments were conducted in seven environments (site x year) with contrasting infestation levels located in Northern Germany from 2013 to 2014. Total ETc was estimated using the FAO dual crop coefficient approach. Crop coefficients were calculated for each cultivar and environment and were adjusted to nematode induced variation in crop canopy and soil cover. Differences in ETc between cultivars within environments were considerably smaller than effects among environments. There was no significant correlation between nematode infestation and ETc valid for all environments. Yield of all cultivars decreased linearly with increasing initial nematode infestation with the strongest response in the susceptible cultivar. Yield of the tolerant and the resistant cultivar under nematode infestation was higher than of the susceptible cultivar. Differences in WUE were primarily associated with yield differences and not due to ETc variability. Higher biomass production of the tolerant and the resistant cultivar under nematode infestation was not associated with higher water use. We concluded that differences in ETc between cultivars were negligibly small and do not affect yield formation. (C) 2015 Elsevier B.V. All rights reserved.Nordzucker AG; Syngenta Agro Gmb
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