95 research outputs found
A RESPONSE OF THE "RESERVOIR-WELL" SYSTEM TO DISTANT EARTHQUAKES
The results of joint processing of hydrogeological and seismic data obtained at the Large-Scale Research Facilities "Mid-Latitude Geophysical Observation Complex "Mikhnevo" for a 12-year observation period are presented in the article. Responses of the "reservoir-well" system to the passage of seismic waves from distant earthquakes with magnitudes of 6.3-9.0, recorded at the epicentral distances from 1863 to 16507 km, have been identified in the database. Maximum values of groundwater level variations and ground velocity under seismic impact have been determined. The power-law dependence of the levels amplitudes of confined and weakly confined aquifers on the maximum vertical ground velocity has been established. A spectral analysis of 6-hour intervals (3 hours before and 3 hours after earthquakes) of seismic and hydrogeological data was performed. The frequencies corresponding to the maximum values of ground velocity and groundwater level variations were determined in the normalized spectra. The intervals within which the extremes of the hydrogeological responses are traced at background values of the ground velocity are identified in the low-frequency range. The amplitude-frequency characteristics of the "reservoir-well" systems differ under seismic impacts at epicentral distances up to 4901 km. The responses of the systems to earthquakes at epicentral distances of 11024-14026 km are similar
РЕАКЦИЯ СИСТЕМ «ПЛАСТ – СКВАЖИНА» НА УДАЛЕННЫЕ ЗЕМЛЕТРЯСЕНИЯ
The results of joint processing of hydrogeological and seismic data obtained at the Large-Scale Research Facilities "Mid-Latitude Geophysical Observation Complex "Mikhnevo" for a 12-year observation period are presented in the article. Responses of the "reservoir-well" system to the passage of seismic waves from distant earthquakes with magnitudes of 6.3-9.0, recorded at the epicentral distances from 1863 to 16507 km, have been identified in the database. Maximum values of groundwater level variations and ground velocity under seismic impact have been determined. The power-law dependence of the levels amplitudes of confined and weakly confined aquifers on the maximum vertical ground velocity has been established. A spectral analysis of 6-hour intervals (3 hours before and 3 hours after earthquakes) of seismic and hydrogeological data was performed. The frequencies corresponding to the maximum values of ground velocity and groundwater level variations were determined in the normalized spectra. The intervals within which the extremes of the hydrogeological responses are traced at background values of the ground velocity are identified in the low-frequency range. The amplitude-frequency characteristics of the "reservoir-well" systems differ under seismic impacts at epicentral distances up to 4901 km. The responses of the systems to earthquakes at epicentral distances of 11024-14026 km are similar.В статье представлены результаты совместной обработки гидрогеологических и сейсмических данных, полученных на уникальной научной установке «Среднеширотный комплекс геофизических наблюдений "Михнево"» ИДГ РАН за 12-летний период наблюдений. В сформированной базе данных выделены отклики системы «пласт – скважина» на прохождение сейсмических волн от удаленных землетрясений с магнитудой 6.3–9.0, зарегистрированных на эпицентральных расстояниях от 1863 до 16507 км. Определены максимальные значения вариаций уровня подземных вод и скорости смещения грунта при сейсмическом воздействии. Установлена степенная зависимость амплитуд уровней напорного и слабонапорного водоносных горизонтов от максимальной скорости смещения грунта по вертикальной компоненте. Выполнен спектральный анализ выборки 6-часовых интервалов (3 ч до и 3 ч после землетрясения) сейсмических и гидрогеологических данных. На нормированных спектрах определены частоты, соответствующие максимальным значениям скорости смещения грунта и вариациям уровня подземных вод. В низкочастотной области выделены интервалы, в пределах которых прослежены экстремумы гидрогеологических откликов при фоновых значениях скорости смещения грунта. Амплитудно-частотные характеристики систем «пласт – скважина» при сейсмическом воздействии на эпицентральных расстояниях до 4901 км различаются. При регистрации землетрясений на эпицентральных расстояниях 11024–14026 км реакция систем подобна
Quantum Entanglement in Nitrosyl Iron Complexes
Recent magnetic susceptibility measurements for polycrystalline samples of
binuclear nitrosyl iron complexes [Fe_2(C_3H_3N_2S)_2(NO)_4] (I) and
[Fe_2(SC_3H_5N_2)_2(NO)_4] (II), suggest that quantum-mechanical entanglement
of the spin degrees of freedom exists in these compounds. Entanglement E exists
below the temperature T_E that we have estimated for complexes I and II to be
80-90 and 110-120 K, respectively. Using an expression of entanglement in terms
of magnetic susceptibility for a Heisenberg dimer, we find the temperature
dependence of the entanglement for complex II. Having arisen at the temperature
T_E, the entanglement increases monotonically with decreasing temperature and
reaches 90-95% in this complex at T=25 K, when the subordinate effects are
still small.Comment: 8 page
Electromagnons in multiferroic RMn2O5 compounds and their microscopic origin
We summarize the existing experimental data on electromagnons in multiferroic
RMn2O5 compounds, where R denotes a rare earth ion, Y or Bi, and discuss a
realistic microscopic model of these materials based on assumption that the
microscopic mechanism of magnetically-induced ferroelectricity and
electromagnon absorption relies entirely on the isotropic Heisenberg exchange
and magnetostrictive coupling of spins to a polar lattice mode and does not
involve relativistic effects. This model explains many magnetic and optical
properties of RMn2O5 manganites, such as the spin re-orientation transition,
magnetically-induced polarisation, appearance of the electromagnon peak in the
non-collinear spin state and the polarisation of light for which this peak is
observed. We compare experimental and theoretical results on electromagnons in
RMn2O5 and RMnO3 compounds.Comment: 20 pages, 9 figures, to be published in J. Phys.: Condens. Matter,
special issue on multiferroic
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Cause of Death and Predictors of All-Cause Mortality in Anticoagulated Patients With Nonvalvular Atrial Fibrillation : Data From ROCKET AF
M. Kaste on työryhmän ROCKET AF Steering Comm jäsen.Background-Atrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all-cause mortality may guide interventions. Methods and Results-In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose-adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all-cause mortality in the 14 171 participants in the intention-to-treat population. The median age was 73 years, and the mean CHADS(2) score was 3.5. Over 1.9 years of median follow-up, 1214 (8.6%) patients died. Kaplan-Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all-cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33-1.70, P= 75 years (hazard ratio 1.69, 95% CI 1.51-1.90, P Conclusions-In a large population of patients anticoagulated for nonvalvular atrial fibrillation, approximate to 7 in 10 deaths were cardiovascular, whereasPeer reviewe
On the shape and likelihood of oceanic rogue waves
We consider the observation and analysis of oceanic rogue waves collected within spatio-Temporal (ST) records of 3D wave fields. This class of records, allowing a sea surface region to be retrieved, is appropriate for the observation of rogue waves, which come up as a random phenomenon that can occur at any time and location of the sea surface. To verify this aspect, we used three stereo wave imaging systems to gather ST records of the sea surface elevation, which were collected in different sea conditions. The wave with the ST maximum elevation (happening to be larger than the rogue threshold 1.25H s) was then isolated within each record, along with its temporal profile. The rogue waves show similar profiles, in agreement with the theory of extreme wave groups. We analyze the rogue wave probability of occurrence, also in the context of ST extreme value distributions, and we conclude that rogue waves are more likely than previously reported; the key point is coming across them, in space as well as in time. The dependence of the rogue wave profile and likelihood on the sea state conditions is also investigated. Results may prove useful in predicting extreme wave occurrence probability and strength during oceanic storms
USAGE OF CARDIOPROTECTION PRINCIPLES IN TREATING CHRONIC HEART FAILURE
Usage of cardioprotection principles in treating chronic heart failure
Role of lipids in molecular thermoadaptation mechanisms of seagrass Zostera marina
By using the combined approaches of microcalorimetric analysis and polarizing microscopy, the crystal-liquid crystal-isotropic melt phase transition of major phospholipids (phosphatidylcholine and phosphatidylethanolamine) and glycolipids (monogalactosyldiacylglycerol and digalactosyldiacylglycerol) isolated from marine seagrass Zostera marina were investigated. Here we discuss the results in view of the fatty acid structures of the lipids studied
Influence of ligand lipophilicity on the NO-donating ability of the binuclear tetranitrosyl iron complexes in an erythrocyte suspension
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