Seismic behaviour of limited ductility buildings

The most important aspects of the seismic design and behaviour of reinforced concrete buildings with limited ductility, like the buildings with waffled slabs or flat beams, are examined in this work. The structures with these typologies are the most used in Spain for new buildings and many seismic codes do not recommend their use in seismic areas. The expected seismic performance of these structures is studied herein by means of incremental non linear structural analysis (pushover analysis) which provides capacity curves. Their behaviour is compared with that of buildings with moment resisting frames designed according to the Spanish EHE and NCSE-02 codes and also to the ACI-318 (2005) and IBC-2003. The most important results of the study show that only the moment-resisting framed buildings exhibit sufficient ductility and overstrength to guarantee a stable seismic behaviour. The behaviour of limited ductility buildings is strongly influenced by the structural type; even if they are reinforced with ductile steel or if their confinement if improved, they exhibit slightly higher ductilit

NONSTANDARD FAREY SEQUENCES IN A REALISTIC DIODE MAP

We study a realistic coupled-map system, modelling a p-i-n diode structure. As we vary the parameter corresponding to the (scaled) external potential in the model the dynamics goes through an exchange of stability bifurcation and a Hopf bifurcation. When the parameter is increased further, we find evidence of a sequence of mode-locked windows embedded in the quasi-periodic motion. These periodic attractors can be ordered according to a Farey tree that is generated between two parent fractions 2/7 and 2/8, where 2/8 implies two distinct coexisting attractors with rho = 1/4, and the correct structure is obtained only when we use the parent fraction 2/8. So, unlike a regular Farey tree, here numerator and denominator of the Farey fractions need not be relative primes. We also checked that the positions and widths of these windows exhibit well-defined power law scaling. When the potential is increased further, the Farey windows still provide a skeleton. for the dynamics, and within each window there is a host of other interesting dynamical features, including multiple forward and reverse Feigenbaum trees.16763564

DYNAMIC BEHAVIOR OF THE FIRINGS IN A COUPLED NEURONAL SYSTEM

The time-interval sequences and the spatiotemporal patterns of the firings of a coupled neuronal network are investigated in this paper. For a single neuron stimulated by an external stimulus I, the time-interval sequences show a low-frequency firing of bursts of spikes and a reversed period-doubling cascade to a high-frequency repetitive firing state as the stimulus I is increased. For two neurons coupled to each other through the firing of the spikes, the complexity of the time-interval sequences becomes simple as the coupling strength increases. A network with a large number of neurons shows a complex spatiotemporal pattern structure. As the coupling strength increases, the number of phase-locked neurons increases and the time-interval diagram shows temporal chaos and a bifurcation in the space. The dynamical behavior is also verified by the behavior of the Lyapunov exponent.4742893289

Alternative splicing of the rat Cav3.3 T-type calcium channel gene produces variants with distinct functional properties11The sequences reported herein have been assigned GenBank accession numbers AY128644–AY128648.

AbstractMolecular diversity in T-type Ca2+ channels is produced by expression of three genes, and alternative splicing of those genes. Prompted by differences noted between rat and human Cav3.3 sequences, we searched for splice variants. We cloned six variants, which are produced by splicing at exon 33 and exon 34. Expression of the variants differed between brain regions. The electrophysiological properties of the variants displayed similar voltage-dependent gating, but differed in their kinetic properties. The functional impact of splicing was inter-related, suggesting an interaction. We conclude that alternative splicing of the Cav3.3 gene produces channels with distinct properties

Incidence and time course of everolimus-related adverse events in postmenopausal women with hormone receptor-positive advanced breast cancer: insights from BOLERO-2.

BackgroundIn the BOLERO-2 trial, everolimus (EVE), an inhibitor of mammalian target of rapamycin, demonstrated significant clinical benefit with an acceptable safety profile when administered with exemestane (EXE) in postmenopausal women with hormone receptor-positive (HR(+)) advanced breast cancer. We report on the incidence, time course, severity, and resolution of treatment-emergent adverse events (AEs) as well as incidence of dose modifications during the extended follow-up of this study.Patients and methodsPatients were randomized (2:1) to receive EVE 10 mg/day or placebo (PBO), with open-label EXE 25 mg/day (n = 724). The primary end point was progression-free survival. Secondary end points included overall survival, objective response rate, and safety. Safety evaluations included recording of AEs, laboratory values, dose interruptions/adjustments, and study drug discontinuations.ResultsThe safety population comprised 720 patients (EVE + EXE, 482; PBO + EXE, 238). The median follow-up was 18 months. Class-effect toxicities, including stomatitis, pneumonitis, and hyperglycemia, were generally of mild or moderate severity and occurred relatively early after treatment initiation (except pneumonitis); incidence tapered off thereafter. EVE dose reduction and interruption (360 and 705 events, respectively) required for AE management were independent of patient age. The median duration of dose interruption was 7 days. Discontinuation of both study drugs because of AEs was higher with EVE + EXE (9%) versus PBO + EXE (3%).ConclusionsMost EVE-associated AEs occur soon after initiation of therapy, are typically of mild or moderate severity, and are generally manageable with dose reduction and interruption. Discontinuation due to toxicity was uncommon. Understanding the time course of class-effect AEs will help inform preventive and monitoring strategies as well as patient education.Trial registration numberNCT00863655

Comportamiento sísmico de edificios de hormigón armado de ductilidad limitada

En el proyecto sismorresistente de edificios es necesario conocer previamente el valor de la ductilidad que éstos podrán llegar a alcanzar al ser sometidos a movimientos sísmicos fuertes. Los valores de ductilidad de referencia están incluidos en las normas de proyecto sismorresistente. Su estimación también puede hacerse bajo criterio de expertos o de la observación de la respuesta que los edificios han tenido ante determinados terremotos. Sin embargo, en el pasado, el problema se ha enfocado generalmente en la respuesta de edificios dúctiles, como son los edificios porticados con vigas de canto, sin que existan muchas referencias que permitan conocer la respuesta de los edificios de ductilidad limitada, entre los que se encuentran los edificios con forjados reticulares, que es la tipología más usual en España. En este trabajo se estudia la respuesta no lineal de edificios de ductilidad limitada, proyectados conforme a los requisitos de la instrucción española (EHE) y la norma sismorresistente NCSE-02, y se obtienen los valores de ductilidad a partir de dicha respuesta, lo que permiten verificar los valores de los factores de reducción aplicados en la determinación de las fuerzas sísmicas y los valores de reserva de resistencia. La evaluación de los edificios se complementa mediante la determinación de las curvas de fragilidad y de las matrices de probabilidad de daño, que permiten conocer la probabilidad de excedencia de Estados Límite previamente establecidos