On fluid approximation for stable networks

Projet MEVALRésumé disponible dans le fichier PD

Ergodicity of conservative communication networks

Projet MEVALWe analyze a communication network with several types of calls. For a wide class of conservative service disciplines, we give ergodicity criteria. Exponentially fast convergence to steady state is also proved

Invasive aspergillosis in patients with COVID-19 in intensive care units: results of a multicenter study

Objective. To study risk factors, clinical and radiological features and effectiveness of the treatment of invasive aspergillosis (IA) in adult patients with COVID-19 (COVID-IA) in intensive care units (ICU). Materials and Methods. A total of 60 patients with COVID-IA treated in ICU (median age 62 years, male – 58%) were included in this multicenter prospective study. The comparison group included 34 patients with COVID-IA outside the ICU (median age 62 years, male – 68%). ECMM/ISHAM 2020 criteria were used for diagnosis of CAPA, and EORTC/MSGERC 2020 criteria were used for evaluation of the treatment efficacy. A case-control study (one patient of the main group per two patients of the control group) was conducted to study risk factors for the development and features of CAPA. The control group included 120 adult COVID-19 patients without IA in the ICU, similar in demographic characteristics and background conditions. The median age of patients in the control group was 63 years, male – 67%. Results. 64% of patients with COVID-IA stayed in the ICU. Risk factors for the COVID-IA development in the ICU: chronic obstructive pulmonary disease (OR = 3.538 [1.104–11.337], p = 0.02), and prolonged (> 10 days) lymphopenia (OR = 8.770 [4.177–18.415], p = 0.00001). The main location of COVID-IA in the ICU was lungs (98%). Typical clinical signs were fever (97%), cough (92%), severe respiratory failure (72%), ARDS (64%) and haemoptysis (23%). Typical CT features were areas of consolidation (97%), hydrothorax (63%), and foci of destruction (53%). The effective methods of laboratory diagnosis of COVID-IA were test for galactomannan in BAL (62%), culture (33%) and microscopy (22%) of BAL. The main causative agents of COVID-IA are A. fumigatus (61%), A. niger (26%) and A. flavus (4%). The overall 12-week survival rate of patients with COVID-IA in the ICU was 42%, negative predictive factors were severe respiratory failure (27.5% vs 81%, p = 0.003), ARDS (14% vs 69%, p = 0.001), mechanical ventilation (25% vs 60%, p = 0.01), and foci of destruction in the lung tissue on CT scan (23% vs 59%, p = 0.01). Conclusions. IA affects predominantly ICU patients with COVID-19 who have concomitant medical conditions, such as diabetes mellitus, hematological malignancies, cancer, and COPD. Risk factors for COVID-IA in ICU patients are prolonged lymphopenia and COPD. The majority of patients with COVID-IA have their lungs affected, but clinical signs of IA are non-specific (fever, cough, progressive respiratory failure). The overall 12-week survival in ICU patients with COVID-IA is low. Prognostic factors of poor outcome in adult ICU patients are severe respiratory failure, ARDS, mechanical ventilation as well as CT signs of lung tissue destruction

Determination criterion far-field for recirculating and cylindrical antenna lattices

В статье рассмотрена возможность определения критерия дальней зоны (ДЗ) для кольцевой и цилиндрической антенных решеток по различным критериям, в частности по уровню боковых лепестков, по уменьшению крутизны пеленгационной характеристики, по уходу нуля пеленгационной характеристики, по ширине главного максимума диаграммы направленности (ДН), по изменению уровня главного максимума ДН.У статті розглядається можливість визначення далекої зони для кільцевої та циліндричної антен за різними критеріями.Possibility of the determination criterion far-field is considered in article for recirculating and cylindrical antennas on different requirements

Structural and magnetic microinhomogeneities in accessory spinel of the system Fe 2+(Cr 2-xFe x 3+)O 4from the Kytlym massif (Urals platinum-bearing belt)

The microstructure and magnetic properties of accessory Fe-Cr-spinels from the Kytlym massif of the Urals platinum-bearing belt were studied. Atypical Fe-Cr-spinels in the form of magnetic microareas in grains of primary nonmagnetic Fe-Cr-spinel have been revealed for the first time in the bed dunites of the Kytlym multiphase concentrically zoned massif, North Urals. These spinels are responsible for the magnetic properties of the dunites. It has been established that the microareas are separations in solid solution Fe 2+(Cr 2-xFe x 3+)O 4, which are enriched in Fe 3+ and are probably an intermediate product of the transformation of primary accessory Fe-Cr-spinel during the formation of the dunite massif. These are magnetic microphases with particular chemical composition, cation distribution, and corresponding reversed crystal lattice, which determine the main magnetic properties of the microarea: the magnitude and direction of magnetization vector and Curie temperature. The formation of this earlier unknown type of magnetic Fe-Cr-spinel is probably conjugate with the formation and concentration of PGE mineralization in the bed dunites of the Kytlym platinum-bearing massif. The presence of such magnetization carriers in rocks and ores must be taken into account in geophysical research at the Urals chromite and platinum-chromite deposits. © 2012

The New 249^{249}No Isotope

International audienceIn the reaction of complete fusion of $^{48}$Ca-ions with a $^{204}$Pb target, a new α line, related to the decay of a new, previously unknown isotope ($^{249}$No), has been detected in an experiment carried out at the SHELS separator. The α decay energy (E$_{α}$ = 9129 keV) and the half-life (T$_{1/2}$ = 38.1 ± 2.5 ms) are measured using the GABRIELA detector array. The SF branching ratio was estimated (b$_{SF}$ ≤ 0.2%)