On the quantum theory of diffraction by an aperture and the Fraunhofer diffraction at large angles

A theoretical model of diffraction based on the concept of quantum measurement is presented. It provides a general expression of the state vector of a particle after its passage through an aperture of any shape in a plane screen (diaphragm). This model meets the double requirement of compatibility with the Huygens-Fresnel principle and with the kinematics of the particle-diaphragm interaction. This led to assume that the diaphragm is a device for measuring the three spatial coordinates of the particle and that the transition from the initial state (incident wave) to the final state (diffracted wave) consists of two specific projections which occur successively in a sequence involving a transitional state. In the case of the diffraction at infinity (Fraunhofer diffraction), the model predicts the intensity of the diffracted wave over the whole angular range of diffraction (0$^{\circ}$ - 90$^{\circ}$). The predictions of the quantum model and of the theories of Fresnel-Kirchhoff (FK) and Rayleigh-Sommerfeld (RS1 and RS2) are close at small diffraction angles but significantly different at large angles, a region for which specific experimental studies are lacking. A measurement of the particle flow intensity in this region should make it possible to test the FK and RS1-2 theories and the suggested quantum model.Comment: 16 pages, 5 figures, improved presentation, more precise and more complete argumentation. Added figures: generalized 3D aperture (Fig.3), circular aperture (Fig. 5). Comment added on Fresnel diffraction. References adde

Effects of mindfulness meditation on conscious and non-conscious components of the mind

The aim of the present review is to investigate previous studies concerning the effects of meditation and dispositional mindfulness on conscious and implicit or non-conscious attitudes. First we present a brief perspective on conscious and non-conscious states of mind. Then we introducethefundamentalbasesofmindfulnessmeditation. Third we review studies on dispositional mindfulness and meditation that employed either direct or indirect measures to assess explicit and implicit attitudes. Finally, we briefly present how meditation has been associated with the psychotherapeutic practice of psychoanalysis and, hence, as a therapeutic technique to access the unconscious. Until now, few studies have investigated the impact of meditation on non-conscious states of mind and personality; nevertheless, both scientific studies involving implicit measures and reflections from psychotherapy have underlined the importance of meditation in promoting psychological well-being, leading to de-automatization of automatic patterns of responding and to higher levels of self-awareness

THE DESIGN OF A PLURAL LAND USE PLANNIG SYSTEM - A TENTATIVE PROPOSAL FROM AN ITALIAN PERSPECTIVE

The main approaches to planning developed during planning history are essentially three: the ritual one, the engineering one and the ethical one. With reference to the last category, classical ethical approaches to planning are those based on the principles of utilitarian (oriented to ensure efficiency and effectiveness for spatial changes), contractualist (oriented to pursue ends of social and environmental equity) and dialogical type (oriented to define planning ends in a public fair dialogue). But these ethical approaches seem inadequate, in their pure forms, to respond to policy-making requirements in our complex urban and regional societies. A really effective and fair system of spatial planning should instead respond not only to situations where ends and means are clear and well-defined but also to situations where there is strong conflict as regards the ends and to situations – perhaps the most frequent ones – where both ends and means are at the same time uncertain. From this standpoint it would seem that experiences (with particular reference to the Italian context) tending towards mixed and plural planning systems, should be regarded with interest. In this perspective, the contribution of the paper is finally addressed towards the definition of a mixed and plural, but loosely coupled, spatial planning system.

Multiparton scattering at the LHC

The large parton flux at high energy gives rise to events where different pairs of partons interact contemporarily with large momentum exchange. A main effect of multiple parton interactions is to generate events with many jets at relatively large transverse momenta. The large value of the heavy quarks production cross section may however give also rise a sizable rate of events with several $b$-quarks produced. We summarize the main features of multiparton interactions and make some estimate of the inclusive cross section to produce two $b{\bar b}$ pairs within the acceptance of the ALICE detector.Comment: 10 pages, 4 figures, contribution to ALICE PP

The Effects of Funding Costs and Risk on Banks' Lending Rates

After falling for over a decade, the major banks' net interest margins appear to have stabilised in a relatively narrow range in recent years. In the early part of the financial crisis, margins fell to the bottom of this range, reflecting an increase in debt funding costs. Margins have since recovered a little, to around the middle of the range, as a result of some repricing of lending rates relative to these costs. In addition to the increase in the cost of debt funding, there have been other drivers of the rise in lending rates relative to the cash rate. First, the banks have increased their equity funding, which is more costly than debt finance. Second, risk margins on loans have risen to account for higher expected losses.funding costs; lending rates; interest rates; risk pricing