Impact of the source-correlation model in jet-noise prediction by acoustic analogy

For both Lilley and moving-frame Lighthill analogies the applied-stress equivalent source is given by the Reynolds stress. Previous jet-noise predictions based on the acoustic analogy adopted a frequency/wave-number source spectrum obtained by applying Fourier transform in space and time on an analytically suitable expression for the Reynolds-stress 2-point cross-correlation coefficient. Very few experimental data for the Reynolds-stress correlation are available in literature. Harper-Bourne has published a limited set of hot-wire measurements taken on a low-speed jet and corresponding to a single location on the nozzle lip line. In this paper a model for the 2-point correlation of the fluctuating Reynolds stress is introduced and compared to two previous correlation models and to the Harper-Bourne data. This shows to which extent the two-point correlation models can be adopted to t the turbulence measurements. The acoustic-source strength per unit volume is modelled in the frequency domain and broken down as product of different factors. The determination of these factors is performed by starting from some suitable 2-point correlation models including the model proposed here and one of the previous models. The output volumetric-strength spectra are used in turn as source master spectrum for a RANS-based jet-noise prediction. This shows the incidence of different correlation models on the estimation of isothermal 90-degree 1/3-octave jet-noise spectra

The Swiss Federation of Clinical Neuro-Societies and Young Clinical Neuroscientists Network.

The Swiss Federation of Clinical Neuro-Societies (SFCNS) was founded in 2009 and currently unites 14 clinical neuroscience associations. Its primary goals are the promotion of clinical, scientific, and educational interdisciplinary collaboration, as well as to establish a united voice towards other organisations, policy makers, and society.1 The SFCNS has received a mandate from the Swiss public health authorities to coordinate the implementation of highly specialised medicine in clinical neuroscience. Similar to the German Neurowoche,2 the SFCNS organises an interdisciplinary congress every 3 years (the next taking place in Lausanne, Switzerland, on Oct 23–25, 2019). This congress and our annual SFCNS Summer School promote education and discussion in clinical neuroscience. Last year, the SFCNS launched the journal Clinical and Translational Neuroscience, as successor of the Swiss Archives of Neurology and Psychiatry, founded by Constantin von Monakow about a century ago..

Sleep-Related Rhythmic Movement Disorder and Obstructive Sleep Apnea in Five Adult Patients.

Sleep-related rhythmic movements (SRRMs) are typical in infancy and childhood, where they usually occur at the wake-to-sleep transition. However, they have rarely been observed in adults, where they can be idiopathic or associated with other sleep disorders including sleep apnea. We report a case series of 5 adults with sleep-related rhythmic movement disorder, 4 of whom had a previous history of SRRMs in childhood. SRRMs mostly occurred in consolidated sleep, in association with pathological respiratory events, predominantly longer ones, especially during stage R sleep, and recovered in 1 patient with continuous positive airway pressure therapy. We hypothesize that sleep apneas may act as a trigger of rhythmic motor events through a respiratory-related arousal mechanism in genetically predisposed subjects

Supplementary Material for: Sleep-Disordered Breathing and Periodic Limb Movements in Narcolepsy with Cataplexy: A Systematic Analysis of 35 Consecutive Patients

<b><i>Background:</i></b> Disturbed sleep is a core feature of narcolepsy with cataplexy (NC). Few studies have independently assessed sleep-disordered breathing (SDB) and periodic limb movements (PLMs) in non-homogeneous series of patients with and without cataplexy. We systematically assessed both SDB and PLMs in well-defined NC patients. <b><i>Methods:</i></b> We analyzed the clinical and polysomnographic features of 35 consecutive NC patients (mean age 40 ± 16 years, 51% males, 23/23 hypocretin-deficient) to assess the prevalence of SDB (apnea-hypopnea index >5) and PLMs (periodic leg movements in sleep (PLMI) >15) together with their impact on nocturnal sleep and daytime sleepiness using the multiple sleep latency test. <b><i>Results:</i></b> 11 (31%) and 14 (40%) patients had SDB and PLMs, respectively. SDB was associated with older age (49 ± 16 vs. 35 ± 13 years, p = 0.02), higher BMI (30 ± 5 vs. 27 ± 6, p = 0.05), and a trend towards higher PLMI (25 ± 20 vs. 12 ± 23, p = 0.052), whereas PLMs with older age (50 ± 16 vs. 33 ± 11 years, p = 0.002) and reduced and fragmented sleep (e.g. sleep efficiency of 82 ± 12% vs. 91 ± 6%, p = 0.015; sleep time of 353 ± 66 vs. 395 ± 28, p = 0.010). SDB and PLMs were also mutually associated (p = 0.007), but not correlated to daytime sleepiness. <b><i>Conclusions:</i></b> SDB and PLMs are highly prevalent and associated in NC. Nevertheless, SDB and PLMs are rarely severe, suggesting an overall limited effect on clinical manifestations

Supplementary Material for: Longitudinal Polysomnographic Assessment from Acute to Subacute Phase in Infratentorial versus Supratentorial Stroke

<b><i>Background:</i></b> Regulation of sleep and sleep-related breathing resides in different brain structures. Vascular lesions can be expected to differ in their consequences on sleep depending on stroke topography. However, studies addressing the differences in sleep and sleep-related breathing depending on stroke topography are scarce. The aim of the present investigation was to compare the sleep and sleep-related breathing of patients with supratentorial versus infratentorial stroke. <b><i>Methods:</i></b> This study was part of the prospective multicenter study SAS-CARE-1 (Sleep-Disordered Breathing in Transient Ischemic Attack (TIA)/Ischemic Stroke and Continuous Positive Airway Pressure (CPAP) Treatment Efficacy (SAS-CARE); NCT01097967). We prospectively included 14 patients (13 male, age 66 ± 6 years) with infratentorial lesions and 14 patients (14 male, age 64 ± 7 years) with supratentorial lesions, matched for age and stroke severity. Polysomnography was recorded in all during the acute phase within 9 days after stroke onset and 3 months later. <b><i>Results:</i></b> During the acute phase after stroke, patients with infratentorial lesions had significantly more sleep-related breathing disorders than patients with supratentorial lesions with an apnea-hypopnea index >20 observed in 8 (57%) patients with infratentorial stroke and in only 2 (14%) patients with supratentorial stroke. Sleep-related breathing improved from the acute to the subacute phase (3 months), albeit remaining elevated in a significant proportion of subjects. Sleep parameters did not differ between the two patient groups but there was a general improvement of sleep from the acute to the subacute phase which was comparable for both patient groups. Although stroke severity was mild, recovery after 3 months was worse in patients with infratentorial stroke with 12 of 14 patients with supratentorial stroke being symptom free (NIHSS = 0), while this was the case for only 6 of 14 patients with infratentorial stroke. <b><i>Conclusions:</i></b> Patients with infratentorial lesions are at an increased risk for sleep-related breathing disorders, which are frequent in this group. Monitoring of sleep-related breathing is therefore especially recommended in patients with infratentorial stroke. Because of the absence of reliable differences in sleep parameters between the two patient groups, polygraphy, with reduced diagnostic costs, rather than polysomnography could be considered. The higher prevalence of sleep-related breathing disorders and the poorer recovery of patients with infratentorial lesions suggest that early treatment interventions should be considered