Experiments on quantum wells in tilted fields have stimulated several groups to investigate semiclassical theories for the current fluctuations. As a result, there is now a sort of “Zoo” of different types of trajectories (Periodic Orbits, Normal Orbits, Central Closed Orbits, Ghost Periodic Orbits, Saddle Orbits, Minimal Orbits) which have all been used to analyse these experimental spectra. Here we review briefly the semiclassical descriptions for this system and discuss which types of trajectories are most appropriate in those regimes where (...) one cannot use Periodic Orbits. We conclude that using either Saddle Orbits (SOs) or Minimal Orbits (MOs) yields excellent agreement with experiment and quantal calculations. We also investigate the damping of the amplitudes of POs (or other semiclassical trajectories). In these scaling systems, different experiments on wells of variable dimensions can correspond to the same classical dynamics and even the same effective ℏ. The trajectory associated with the experimental current oscillation is unchanged: the only significant alteration is a re-scaling of the period T of the PO, affecting only the amplitude damping factors τe−T/τ due to incoherent processes in the experiment. By comparing measurements of the same period-doubling feature of the current in 85 nm and 120 nm wells we can probe the value of τ from the change in the PO (or SO/MO) amplitudes which are estimated from the experiment. (shrink)

This study investigated the importance of socioeconomic factors such as education, income, religion, family structure and residence in explaining the increased risk of mortality among vulnerable populations aged less than 20 years in Rio de Janeiro, Brazil. Data used were from the 1991 Brazilian Demographic Census and comprised 121,060 women aged 15–49 residing in Rio de Janeiro. Two alternative statistical methods were used to calculate the risk of death: the widely used Brass method (an indirect estimate which assesses population risks) (...) and a case-control study (which assesses individual risks). The study also focused on the importance of indicators of human and social capital, the lack of which may explain the higher risk of death among children and adolescents. Lack of education was found to be a major determinant of mortality at young ages. Residence in a favela (shantytown), families in which mothers were the head of the family, and a lower median level of income were found to be significant determinants of mortality among vulnerable populations in Brazil. However, religion was not found to be as important a predictor of high mortality. (shrink)

Logical Forms explains both the detailed problems involved in finding logical forms and also the theoretical underpinnings of philosophical logic. In this revised edition, exercises are integrated throughout the book. The result is a genuinely interactive introduction which engages the reader in developing the argument. Each chapter concludes with updated notes to guide further reading.

Describes Bradley's doctrine of 'immediate experience' as a starting point of knowledge, then traces the development of the of subject and object out of immediate experience, with the question of independence, and with the precise meaning of the term 'objectivity.'.

Книга предназначена для философов, правоведов и специалистов по естественным наукам, а также для заинтересованных читателей.

Книга предназначена для философов, правоведов и специалистов по естественным наукам, а также для заинтересованных читателей.

Memoirs and papers presented at a conference held on the occasion of the 90th birthday of the Mongolian philosopher Ts. Balkhaajav.

We explicitly compute, following the method of Weyl, the commutator [Q, P] of the position operatorQ and the momentum operatorP of a particle when the dimension of the space on which they act is finite with a discrete spectrum; and we show that in the limit of a continuous spectrum with the dimension going to infinity this reduces to the usual relation of Heisenberg.

В монографии рассматриваются возможности применения обобщенной релевантной логики к проблеме моделирования рассуждений. Для научных работников, аспирантов, студентов, специалистов в философской логике, аргументации и компьютерной науке.

Издание посвящено проблемам образной семантики, которые затрагивают четыре явления - когнитивные модели сравнительных конструкций, метафорические структуры языка, культурно значимая фразеология и поэтический дискурс.

Recently we have studied quantum mechanics of bounded operators with a discrete spectrum. In particular, we derived an expression for the commutator[Q, P] of two bounded operators whose spectrum is discrete, and we showed that in the limit of a continuous spectrum the commutator becomes the standard one of Heisenberg. In this paper we show that the angular momentum operator and the phase operator satisfy the new commutation relation. We also briefly discuss the problem of the canonical phase operator conjugate (...) to the number operator. (shrink)