Switched Spatial Impulse Response Convolution as an Ambisonic Distance-Panning Function

Ambisonics offers a robust and effective approach to the recording, processing and delivery of Spatial Audio. The Ambisonic system is often considered to provide a perceptually and computationally advantageous Spatial Audio experience in comparison to typical Binaural systems. This is true even when an end-step Binaural render is required, as is typical in Virtual or Augmented Reality systems which naturally imply audio delivery via headphones. Standard Ambisonic processing allows for the rotation of a sound field around an origin position. There is not, however, a strongly established means of modulating the radial distance of a virtual sound source from the origin. This paper presents a potential solution to an Ambisonic distance-panning function for both static and dynamic virtual sources in the form of a FOA (First Order Ambisonics) Switched-SIR (Spatial Impulse Response) Convolution Reverberator. This includes a presentation of the framework for such a function, and an analysis of audio rendered using prototype scripts

Validity and limitations of simple reaction kinetics to calculate concentrations of organic compounds from ion counts in PTR-MS

In September 2017, we conducted a proton-transfer-reaction mass-spectrometry (PTR-MS) intercomparison campaign at the CESAR observatory, a rural site in the central Netherlands near the village of Cabauw. Nine research groups deployed a total of 11 instruments covering a wide range of instrument types and performance. We applied a new calibration method based on fast injection of a gas standard through a sample loop. This approach allows calibrations on timescales of seconds, and within a few minutes an automated sequence can be run allowing one to retrieve diagnostic parameters that indicate the performance status. We developed a method to retrieve the mass-dependent transmission from the fast calibrations, which is an essential characteristic of PTR-MS instruments, limiting the potential to calculate concentrations based on counting statistics and simple reaction kinetics in the reactor/drift tube. Our measurements show that PTR-MS instruments follow the simple reaction kinetics if operated in the standard range for pressures and temperature of the reaction chamber (i.e. 1-4 mbar, 30-120 degrees, respectively), as well as a reduced field strength E/N in the range of 100-160 Td. If artefacts can be ruled out, it becomes possible to quantify the signals of uncalibrated organics with accuracies better than +/- 30 %. The simple reaction kinetics approach produces less accurate results at E/N levels below 100 Td, because significant fractions of primary ions form water hydronium clusters. Deprotonation through reactive collisions of protonated organics with water molecules needs to be considered when the collision energy is a substantial fraction of the exoergicity of the proton transfer reaction and/or if protonated organics undergo many collisions with water molecules.Peer reviewe

β-Adrenoreceptor Stimulation Mediates Reconsolidation of Social Reward-Related Memories

In recent years, the notion that consolidated memories become transiently unstable after retrieval and require reconsolidation to persist for later use has received strong experimental support. To date, the majority of studies on reconsolidation have focused on memories of negative emotions, while the dynamics of positive memories have been less well studied. Social play, the most characteristic social behavior displayed by young mammals, is important for social and cognitive development. It has strong rewarding properties, illustrated by the fact that it can induce conditioned place preference (CPP). In order to understand the dynamics of positive social memories, we evaluated the effect of propranolol, a β-adrenoreceptor antagonist known to influence a variety of memory processes, on acquisition, consolidation, retrieval and reconsolidation of social play-induced CPP in adolescent rats.Systemic treatment with propranolol, immediately before or after a CPP test (i.e. retrieval session), attenuated CPP 24 h later. Following extinction, CPP could be reinstated in saline--but not in propranolol-treated rats, indicating that propranolol treatment had persistently disrupted the CPP memory trace. Propranolol did not affect social play-induced CPP in the absence of memory retrieval or when administered 1 h or 6 h after retrieval. Furthermore, propranolol did not affect acquisition, consolidation or retrieval of social play-induced CPP.We conclude that β-adrenergic neurotransmission selectively mediates the reconsolidation, but not other processes involved in the storage and stability of social reward-related memories in adolescent rats. These data support the notion that consolidation and reconsolidation of social reward-related memories in adolescent rats rely on distinct neural mechanisms

Pd(111) versus Pd–Au(111) in carbon monoxide oxidation under elevated pressures

International audienceThe oxidation of CO on Pd(111) and Pd70Au30(111) has been studied under pressures upto 100 Torr. Gold is found to decrease the surface activity by inhibiting oxygen dissociation. For a sufficient conversion time depending on the CO coverage and the surface identity, a dramatic boost of activity occurs. This is ascribed to a switch from CO-induced inhibition of O2 adsorption to a regime determined by CO adsorption. The other kinetic features are explained by oxidation of palladium and adsorption-induced restructuring of the surfaces

2D Sub-Pixel Disparity Measurement Using QPEC / Medicis

In the frame of its earth observation missions, CNES created a library called QPEC, and one of its launcher called Medicis. QPEC / Medicis is a sub-pixel two-dimensional stereo matching algorithm that works on an image pair. This tool is a block matching algorithm, which means that it is based on a local method. Moreover it does not regularize the results found. It proposes several matching costs, such as the Zero mean Normalised Cross-Correlation or statistical measures (the Mutual Information being one of them), and different match validation flags. QPEC / Medicis is able to compute a two-dimensional dense disparity map with a subpixel precision. Hence, it is more versatile than disparity estimation methods found in computer vision literature, which often assume an epipolar geometry. CNES uses Medicis, among other applications, during the in-orbit image quality commissioning of earth observation satellites. For instance the Pléiades-HR 1A & 1B and the Sentinel-2 geometric calibrations are based on this block matching algorithm. Over the years, it has become a common tool in ground segments for in-flight monitoring purposes. For these two kinds of applications, the two-dimensional search and the local sub-pixel measure without regularization can be essential. This tool is also used to generate automatic digital elevation models, for which it was not initially dedicated. This paper deals with the QPEC / Medicis algorithm. It also presents some of its CNES applications (in-orbit commissioning, in flight monitoring or digital elevation model generation). Medicis software is distributed outside the CNES as well. This paper finally describes some of these external applications using Medicis, such as ground displacement measurement, or intra-oral scanner in the dental domain

On the origin of the transthyretin Val30Met familial amyloid polyneuropathy

Transthyretin (TTR) familial amyloid polyneuropathy is a severe autosomal dominant neuropathy of adulthood, frequently linked to the pathogenic Val30Met variant of the TTR gene. The condition was initially described in northern Portugal, which is the first focus of the disease. Other important clusters of families are found in Sweden, Japan and South America. The origin of the Val30Met mutation and its distribution through the populations remains unclear. In the present work, we aimed at refining the history of the Val30Met mutation in patients affected with TTR amyloid neuropathy from Portugal, Sweden and Brazil. The decay of haplotype sharing was studied in 60 patients to estimate the age of the Most Recent Common Ancestor (MRCA) of mutation carriers in these populations. Our results showed a common haplotype in Portuguese and Brazilian patients and an age estimate of the MRCA of 750 and 650 years, respectively. In contrast, a different haplotype was found in the Swedish Val30Met patients with a corresponding age estimate for the MRCA, of 375 years. This work strengthens the hypothesis of different founders in Portuguese and Swedish Val30Met carriers and suggested a Portuguese origin of the Brazilian mutation. The age estimates of the MRCA are in line with the current historical knowledge of these populations

Risk factors for bleeding, including platelet count threshold, in newly diagnosed immune thrombocytopenia adults

International audienceEssentials Risk factors of bleeding in adult immune thrombocytopenia are not known. This multicenter study assessed risk factors of bleeding at immune thrombocytopenia onset. Platelet count thresholds associated with bleeding were < 20 × 109 L-1 and < 10 × 109 L-1 . Exposure to anticoagulants was a major risk factor of severe bleeding.Summary: Background The aim of this cross-sectional study was to assess risk factors for bleeding in immune thrombocytopenia (ITP) adults, including the determination of platelet count thresholds. Methods We selected all newly diagnosed ITP adults included in the Cytopénies Auto-immunes Registre Midi-PyrénéEN (CARMEN) register and at the French referral center for autoimmune cytopenias. The frequencies of any bleeding, mucosal bleeding and severe bleeding (gastrointestinal, intracranial, or macroscopic hematuria) at ITP onset were assessed. Platelet count thresholds were assessed by the use of receiver operating characteristic curves. All potential risk factors were included in logistic regression models. Results Among the 302 patients, the frequencies of any, mucosal and severe bleeding were 57.9%, 30.1%, and 6.6%, respectively. The best discriminant threshold of platelet count for any bleeding was 20 × 109 L-1 . In multivariate analysis, factors associated with any bleeding were platelet count (< 10 × 109 L-1 versus ≥ 20 × 109 L-1 , odds ratio [OR] 48.2, 95% confidence interval [CI] 20.0-116.3; between 10 × 109 L-1 and 19 × 109 L-1 versus ≥ 20 × 109 L-1 , OR 5.2, 95% CI 2.3-11.6), female sex (OR 2.6, 95% CI 1.3-5.0), and exposure to non-steroidal anti-inflammatory drugs (NSAIDs) (OR 4.8, 95% CI 1.1-20.7). A low platelet count was also the main risk factor for mucosal bleeding. Exposure to anticoagulant drugs was associated with severe bleeding (OR 4.3, 95% CI 1.3-14.1). Conclusions Platelet counts of < 20 × 109 L-1 and < 10 × 109 L-1 were thresholds for major increased risks of any and mucosal bleeding. Platelet count, female sex and exposure to NSAIDs should be considered for assessment of the risk of any bleeding. Exposure to anticoagulant drugs was a major risk factor for severe bleeding

Predictors of Response to Erythropoietin in Autoimmune Hemolytic Anemia

BACKGROUND AND AIM Bone marrow compensation in autoimmune hemolytic anemia (AIHA) is an emerging predictor of clinical outcome. It is measured by reticulocytosis that may be inadequate in a proportion of cases, particularly in chronic refractory ones. Moreover, reticulocytosis may be masked by constant destruction, particularly in cold forms. Recombinant erythropoietin (EPO), has been anecdotally used off-label in AIHA to improve anemia, but only case reports and small series have been described. Here we evaluate EPO efficacy and predictors of response in a multicentric cohort of primary and secondary AIHA patients. METHODS Hematological data, hemolytic markers (LDH, reticulocytes), and concomitant treatments were retrospectively and prospectively collected. Efficacy was evaluated at 15 and 30 days, and then at 3,6 and 12 months after EPO start. Response was considered as partial (PR, &gt;2 g/dL Hb increase or &gt;10 g/dL) or complete (CR, &gt;12g/dL and normalization of hemolytic markers). Forty-six AIHA cases followed from June 2007 to June 2019 at 9 centers in Italy, France, Norway, Austria, Denmark, and UK were included. RESULTS Table 1 shows patients characteristics: all AIHA types (warm, cold, mixed, and DAT negative) were present, and 5 cases were secondary to a lymphoproliferative disorder (not active and without specific treatment at the time of EPO start). Bone marrow evaluation pre-EPO (N=24) showed hypercellularity in 14 cases, dyserythropoiesis in 11, and reticulin fibrosis in 3; a lymphoid infiltrate was found in 19 patients (T-cell in 6, B-cell in 10, mixed in 3), greater than 10% in the 5 secondary cases only. Forty-one cases (89%) had been previously treated, with a mean of 1.8+1 lines of therapy including steroids, rituximab, splenectomy, immunosuppressors and sutimlimab (1 case, where the drug completely abolished hemolysis). The majority (67%) started EPO due to non-response to ongoing treatment (18 steroids, 6 immunosuppressors, 1 sutimlimab) or within 3 months from rituximab course (7). At EPO initiation, 30% of cases displayed severe anemia, 71% had inadequate reticulocytosis (bone marrow responsiveness index&lt;121), and 73% showed inappropriately low endogenous EPO levels. Of note, 2 patients had concomitant renal impairment, possibly contributing to this finding. Most cases received epoetin alpha 40,000 UI/week (45%), followed by darbopoetin alpha (34% of cases, median dose 102 mcg/week) and epoetin zeta (14% of cases, 30,000 UI/week). EPO was administered for a median of 6 months and responses were observed in 68% and 70% of cases at month+1 and +3. Comparable response rates were recorded at month+6 (70%, 13 CR and 1 PR, N=20) and +12 (72%, 8 CR and 5 PR, N=18), although evaluable cases were fewer. Median Hb increase from baseline was 2.5 g/dL (0.2-7.6) at month+1 (p&lt;0.001), and 3.1 g/dL (0-9.4) at month+3 (p&lt;0.001). Consistently, reticulocytes increased by 23 x109/L (0-217) at month+1, and 33 x109/L (0-353) at month+3. No EPO-related adverse events occurred (particularly no thrombosis). At last follow up, 23 cases had discontinued EPO: 13 for long lasting CR and 10 because of NR. Considering predictors of response, a better efficacy was observed in primary versus secondary AIHA (71 vs 40%) and in patients with shorter time from diagnosis to EPO treatment (52% of responders started EPO within 1 year from diagnosis vs 8% of NR, p=0.01). Moreover, responders had received a lower number of previous treatments (p=0.04), particularly rituximab (p=0.05) and immunosuppressors (p=0.08). Remarkably, responders more frequently showed severe anemia (86% vs 62%) and lower endogenous EPO (91% vs 50% with a cut-off of &lt;60 UI/L, p=0.05) at baseline. CONCLUSIONS EPO is effective in roughly 70% of chronic refractory AIHA cases, independently from antibody thermal characteristics/isotype and underlying disease. Concomitant treatments may partially affect response evaluation, although EPO treatment has been introduced because of their partial or complete inefficacy. Further limitations are the retrospective nature of the study and a possible selection bias (i.e. most of patients had inadequate reticulocytosis). Predictors of response were severe anemia and low levels of endogenous EPO, as well as, shorter disease duration and a lower burden of previous treatments. These data suggest an early use of EPO in this setting in order to overcome inadequate bone marrow compensatory ability