1,139 research outputs found
On the Hierarchical Preconditioning of the PMCHWT Integral Equation on Simply and Multiply Connected Geometries
We present a hierarchical basis preconditioning strategy for the
Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) integral equation considering
both simply and multiply connected geometries.To this end, we first consider
the direct application of hierarchical basis preconditioners, developed for the
Electric Field Integral Equation (EFIE), to the PMCHWT. It is notably found
that, whereas for the EFIE a diagonal preconditioner can be used for obtaining
the hierarchical basis scaling factors, this strategy is catastrophic in the
case of the PMCHWT since it leads to a severly ill-conditioned PMCHWT system in
the case of multiply connected geometries. We then proceed to a theoretical
analysis of the effect of hierarchical bases on the PMCHWT operator for which
we obtain the correct scaling factors and a provably effective preconditioner
for both low frequencies and mesh refinements. Numerical results will
corroborate the theory and show the effectiveness of our approach
Traffic flow on realistic road networks with adaptive traffic lights
We present a model of traffic flow on generic urban road networks based on
cellular automata. We apply this model to an existing road network in the
Australian city of Melbourne, using empirical data as input. For comparison, we
also apply this model to a square-grid network using hypothetical input data.
On both networks we compare the effects of non-adaptive vs adaptive traffic
lights, in which instantaneous traffic state information feeds back into the
traffic signal schedule. We observe that not only do adaptive traffic lights
result in better averages of network observables, they also lead to
significantly smaller fluctuations in these observables. We furthermore compare
two different systems of adaptive traffic signals, one which is informed by the
traffic state on both upstream and downstream links, and one which is informed
by upstream links only. We find that, in general, both the mean and the
fluctuation of the travel time are smallest when using the joint
upstream-downstream control strategy.Comment: 41 pages, pdflate
Dopamine precursor depletion improves punishment prediction during reversal learning in healthy females but not males
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Infective endocarditis in patients after percutaneous pulmonary valve implantation with the stent-mounted bovine jugular vein valve : clinical experience and evaluation of the modified Duke criteria
Percutaneous pulmonary valve implantation (PPVI) has proven good hemodynamic results. As infective endocarditis (IE) remains a potential complication with limited available clinical data, we reviewed our patient records to improve future strategies of IE prevention, diagnosis and treatment. Medical records of all patients diagnosed with Melody® valve IE according to the modified Duke criteria were retrospectively analyzed in three Belgian tertiary centers. 23 IE episodes in 22 out of 240 patients were identified (incidence 2.4% / patient year) with a clear male predominance (86%). Median age at IE was 17.9 years (range 8.2-45.9 years) and median time from PPVI to IE was 2.4 years (range 0.7-8 years). Streptococcal species caused 10 infections (43%), followed by Staphylococcus aureus (n = 5, 22%). In 13/23 IE episodes a possible entry-point was identified (57%). IE was classified as definite in 15 (65%) and as possible in 8 (35%) cases due to limitations of imaging. Echocardiography visualized vegetations in only 10 patients. PET-CT showed positive FDG signals in 5/7 patients (71%) and intracardiac echocardiography a vegetation in 1/1 patient (100%). Eleven cases (48%) had a hemodynamically relevant pulmonary stenosis at IE presentation. Nine early and 6 late percutaneous or surgical re-interventions were performed. No IE related deaths occurred. IE after Melody® valve PPVI is associated with a relevant need of re-interventions. Communication to patients and physicians about risk factors is essential in prevention. The modified Duke criteria underperformed in diagnosing definite IE, but inclusion of new imaging modalities might improve diagnostic performance
Do Surgical Interventions Influence Psychosexual and Cosmetic Outcomes in Women with Disorders of Sex Development?
Clinical practice developed to promote psychosexual well-being in DSD is under scrutiny. Although techniques for genital surgery have much improved lately, long-term studies on psychosexual functioning and cosmetic outcome on which to base treatment and counseling are scarce. We studied 91 women with a DSD. Feminizing surgery was performed in 64% of the women; in 60% of them, resurgery in puberty was needed after a single-stage procedure. Both patients and gynecologists were satisfied with the cosmetic appearance of the genitalia. However, forty percent of these females experienced sexuality-related distress and 66% was at risk for developing a sexual dysfunction, whether they had surgery or not. Recognizing the difficulty of accurate assessment, our data indicate that feminizing surgery does not seem to improve nor hamper psychosexual outcome, especially in patients with severe virilization
Asymmetric simple exclusion process describing conflicting traffic flows
We use the asymmetric simple exclusion process for describing vehicular
traffic flow at the intersection of two streets. No traffic lights control the
traffic flow. The approaching cars to the intersection point yield to each
other to avoid collision. This yielding dynamics is model by implementing
exclusion process to the intersection point of the two streets. Closed boundary
condition is applied to the streets. We utilize both mean-field approach and
extensive simulations to find the model characteristics. In particular, we
obtain the fundamental diagrams and show that the effect of interaction between
chains can be regarded as a dynamic impurity at the intersection point.Comment: 7 pages, 10 eps figures, Revte
A linear 19-Mer plant defensin-derived peptide acts synergistically with caspofungin against Candida albicans biofilms.
Transplantation and autoimmunit
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Assessing market attractiveness for mergers and acquisitions: the M&A Attractiveness Index Score
This paper presents a new scoring methodology designed to measure a country's capability to attract and sustain business investment activity in the forms of cross-border inflow and domestic mergers and acquisitions (M&A). We compute a theoretically grounded Index of Attractiveness for M&A purposes based on groups of country development factors which have been identified as key drivers of corporate investment activity in economics, finance and management literature. By using the Index, which has been successfully tested against country-level M&A activity in a time series analysis, we show that the drivers of M&A activity differ significantly at different stages of country maturity. Specifically, for mature countries, the quality of their regulatory systems, political stability, socio-economic environment and the sophistication of their physical infrastructure as well as the availability of sizeable assets all determine differences in country-level M&A volume and value activity. For countries at the transitional stage, it is instead their economic and financial health, socio-economic environment, technological developments and the quality of their infrastructure and the availability of sizeable assets which drive M&A activity. We also prove the predictability power of the Index, by a set of Granger causality tests, showing not only how country-level development drives future M&A activity but also how, to some extent, the inverse relationship is also true, i.e. that M&A activity can contribute to country development
The effect of dopamine agonists on adaptive and aberrant salience in Parkinson's disease
Clinical evidence suggests that after initiation of dopaminergic medications some patients with Parkinson's disease (PD) develop psychotic symptoms, such as hallucinations and delusions. Here, we tested the hypothesis that the neurocognitive basis of this phenomenon can be defined as the formation of arbitrary and illusory associations between conditioned stimuli and reward signals, called aberrant salience. Young, never-medicated PD patients and matched controls were assessed on a speeded reaction time task in which the probe stimulus was preceded by conditioned stimuli that could signal monetary reward by color or shape. The patients and controls were re-evaluated after 12 weeks during which the patients received a dopamine agonist (pramipexole or ropinirole). Results indicated that dopamine agonists increased both adaptive and aberrant salience in PD patients, that is, formation of real and illusory associations between conditioned stimuli and reward, respectively. This effect was present when associations were assessed by means of faster responding after conditioned stimuli signaling reward (implicit salience) and overt rating of stimulus-reward links (explicit salience). However, unusual feelings and experiences, which are subclinical manifestations of psychotic-like symptoms, were specifically related to irrelevant and illusory stimulus-reward associations (aberrant salience) in PD patients receiving dopamine agonists. The learning of relevant and real stimulus-reward associations (adaptive salience) was not related to unusual experiences. These results suggest that dopamine agonists may increase psychotic-like experiences in young patients with PD, possibly by facilitating dopaminergic transmission in the ventral striatum, which results in aberrant associations between conditioned stimuli and reward
The short-term effect of swimming training load on shoulder rotational range of motion, shoulder joint position sense and pectoralis minor length
Background: Shoulder pain or injury is the most common issue facing elite competitive swimmers and the most frequent reason for missed or modified training. Literature suggests that highly repetitive upper limb loading leads to inappropriate adaptations within the shoulder complex. The most likely maladaptations to occur are variations in shoulder rotational range of motion, reduction in joint position sense and shortened pectoralis minor length. This has yet to have been confirmed in experimental studies. The aim of this study was to investigate the short-term effects of swimming training load upon internal and external rotation range of motion, joint position sense and pectoralis minor length.
Method: Sixteen elite swimmers training in the British Swimming World Class programme participated. Measures of internal and external range of motion, joint position sense error score and pectoralis minor length were taken before and after a typical 2h swimming session.
Results: Following swimming training shoulder external rotation range of motion and pectoralis minor length reduced significantly (-3.4°,p=<0.001 and -0.7cm, p=<0.001, respectively), joint position sense error increased significantly (+2.0° error angle, p=<0.001). Internal rotation range of motion demonstrated no significant change (-0.6, p=0.53).
Discussion: This study determined that elite level swimming training results in short-term maladaptive changes in shoulder performance that could potentially predispose them to injury
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