Search results for " Stab"
showing 10 items of 1773 documents
Binaurālo pukstu ietekme uz EEG un stājas stabilitāti
2016
Pētījums attiecas uz aktuālu klīniskās fizioloģijas un neirozinātnes problēmu, kura ir saistīta ar dažādu eksogēnu stimulu spēju ietekmēt gan cilvēka smadzeņu darbību, gan stājas stabilitāti. Pētījums veikts ar mērķi noskaidrot binaurālo pukstu (BP) stimulācijas ietekmi uz pieaugušu jaunu cilvēku nomoda elektroencefalogrammu (EEG) un stājas stabilitātes parametriem, kā arī savstarpēji salīdzinoši novērtēt vairākus objektīvus un subjektīvus BP sensitivitātes kritērijus. Binaurālo pukstu tūlītējās, daudzbusīgās ietekmes kopaina ir īpatnēja katram indivīdam, līdz ar to – indivīda binaurālo pukstu jutības (sensitivitātes) vērtējumā ir jāizmanto vairāku fizioloģisko reakciju spilgtumu raksturojo…
Kognitīvo uzdevumu ietekme uz stājas stabilitāti jauniem un veciem cilvēkiem
2017
Kopsavilkums Palielinoties cilvēka vecumam, palielinās kritienu un traumatisma riski. Tā kā Latvijā, kā arī Eiropā kopumā, palielinās populācijas novecošanās, kritienu un traumatisma riski pieaug, un to samazināšanai ir nepieciešami efektīvi profilaktiski pasākumi, kas uzlabotu īpaši gados veco cilvēku mobilitāti un novērstu kritienus. Pašreiz nav vienotu vadlīniju stājas stabilitātes pārbaužu metodikā un uzlabošanā, tādēļ ir nozīmīgi izprast faktorus, kas var ietekmēt posturālo kontroli. Tādejādi darbā tika izvirzīts mērķis noskaidrot kognitīvo procesu ietekmi uz stājas stabilitāti, kā arī izvērtēt antropometrisko parametru ietekmi uz līdzsvara saglabāšanu. Pētījumā piedalījās 60 izmeklēja…
Pseudospectrum of Reissner-Nordström black holes: Quasinormal mode instability and universality
2021
Black hole spectroscopy is a powerful tool to probe the Kerr nature of astrophysical compact objects and their environment. The observation of multiple ringdown modes in gravitational waveforms could soon lead to high-precision gravitational spectroscopy, so it is critical to understand if the quasinormal mode spectrum is stable against perturbations. It was recently shown that the pseudospectrum can shed light on the spectral stability of black hole quasinormal modes. We study the pseudospectrum of Reissner-Nordstr\"om spacetimes and we find a spectral instability of scalar and gravitoelectric quasinormal modes in subextremal and extremal black holes, extending similar findings for the Sch…
Indagine sperimentale sul comportamento di pareti sismiche in acciaio sottoposte a taglio
2005
The paper concerns the experimental results performed on steel (S 235) zinc plated panels having 1500 x 1150 x 1.5 mm dimensions, linked to hinged steel frame. In order to the slenderness of plates, considerable displacements out-of-plane are evident at loads significantly lower of ultimate load. Considering the steel constitutive curves obtained from tensile tests, the comparison of experimental and numerical (ADINA) results is proposed. The results show the excellent seismic behaviour of the system having stable hysteresis loops.
Progetto di Strutture in acciaio per le nuove costruzioni e per gli interventi di consolidamento. IV Edizione
2005
The book is a state of the art summary of recent development in the behavior, analysis and design of steel and composite structures. The book provides advanced students, researchers al professionals in civil and structural engineering with the basic principles upon which the modern codes are based. In the first part, the materials, the actions and the sectional behavior are analyzed on the base of the limit state theory. Then the connections (bolted and welded)and the stability effects are examined. In this way is possible speak about seismic performance, retrofitting an refurbishment of existing buildings, referring to the italian rules, to the european codes EC3, EC4 and to the AISC rules.
Stability of stochastic nonlinear systems with state-dependent switching
2013
In this paper, the problem of stability on stochastic systems with state-dependent switching is investigated. To analyze properties of the switched system by means of Itô’s formula and Dynkin’s formula, it is critical to show switching instants being stopping times. When the given active-region set can be replaced by its interior, the local solution of the switched system is constructed by defining a series of stopping times as switching instants, and the criteria on global existence and stability of solution are presented by Lyapunov approach. For the case where the active-region set can not be replaced by its interior, the switched systems do not necessarily have solutions, thereby quasi-…
Crystal structure and Hirshfeld surface analysis of [N(CH3)4][2,2′-Fe(1,7-closo-C2B9H11)2]
2017
Abstract This work investigates the meta -ferrabis(dicarbollide) anion that was isolated as salt of tetramethylammonium. The structure of the obtained crystal consisted of discrete [2,2′-Fe(1,7- closo -C 2 B 9 H 11 ) 2 ] − anions and disordered [N(CH 3 ) 4 ] + cations. The anion had a considerable chemical stability ensured by ionic and Van der Waals interactions. Thus, Hirshfeld surfaces and fingerprint plot were used to visualize, explore, and quantify intermolecular interactions in the crystal lattice of the title compound. This investigation proved that close contacts were dominated by H⋯H interactions.
Gas geochemistry of shallow submarine vents in the Aegean sea (Greece)
2017
The Aegean area, which is geodynamically very active, is characterised by intense seismic activity, presence of active volcanic systems and anomalous geothermal gradients. Like other regions of intense geodynamic activity it is also characterized by extensive geogenic degassing. Gas manifestations are not only widespread on land but are also very frequent underwater. Many of these, as for example those of Milos and Santorini, are known since long time and have been previously studied although the targets were generally the hot waters or the sediments affected by the emissions (Smith and Cronan 1978, Dando et al. 1995, Price et al. 2013, Megalovassilis 2014).The present study aims at produci…
Effect of two distinct implant macro-designs on the osseointegration of bicortically installed implants in two topographic sites. A histomorphometric…
2019
Antecedentes científicos y objetivos de estudio: El uso de implantes dentales como alternativa para la rehabilitación oral ha demostrado su eficacia y mostrando altas tasas de supervivencia. Un aspecto clave de la osteointegración del implante dental está relacionado con la obtención de una estabilidad primaria adecuada, asegurada por el enclavamiento mecánico entre el tejido óseo y la interfaz del implante, la cual depende en parte de la geometría del implante, la rugosidad de la superficie y la técnica quirúrgica para la preparación del lecho implantario. Varios factores están involucrados en la interacción entre la superficie del implante y el hueso nativo circundante durante la osteoint…
Classical and reverse substituent effects in meta- and para-substituted nitrobenzene derivatives
2017
Electron-accepting properties of the nitro group were studied in a series of meta- and para-X-substituted nitrobenzene derivatives (X = NMe2, NH2, OH, OMe, CH3, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, COCl, NO2, NO). For this purpose Hammett-like approaches were applied based on quantum chemistry modeling; the B3LYP/6-311++ G(d,p) method was used. The substituent effect (SE) was characterized by the mutually interrelated descriptors: the charge of the substituent active region, cSAR(X), and substituent effect stabilization energy, SESE, as well as substituent constants, σ. Classical SE is realized by dependences of the structural parameters of the nitro group (ONO angle and NO bond lengt…