A 1D Model for N-level Atoms Coupled to an EM Field

We construct a model for n-level atoms coupled to quantized electromagnetic fields in a fibrillar geometry. In the slowly varying envelope and rotating wave approximations, the equations of motion are shown to satisfy a zero curvature representation, implying integrability of the quantum system.Comment: 8 pages, Plain Te

The quantum theory of measurement within dynamical reduction models

We analyze in mathematical detail, within the framework of the QMUPL model of spontaneous wave function collapse, the von Neumann measurement scheme for the measurement of a 1/2 spin particle. We prove that, according to the equation of the model: i) throughout the whole measurement process, the pointer of the measuring device is always perfectly well localized in space; ii) the probabilities for the possible outcomes are distributed in agreement with the Born probability rule; iii) at the end of the measurement the state of the microscopic system has collapsed to the eigenstate corresponding to the measured eigenvalue. This analysis shows rigorously how dynamical reduction models provide a consistent solution to the measurement problem of quantum mechanics.Comment: 24 pages, RevTeX. Minor changes mad

Persuasion: A Case Study of Papal Influences on Fertility-Related Beliefs and Behavior

We study the persuasive impacts of non-informative communication on the short-run beliefs and long-run behavior of individuals. We do so in the context of the Papal visit to Brazil in October 1991, in which persuasive messages related to fertility were salient in Papal speeches during the visit. We use individual’s exposure to such messages to measure how persuasion shifts: (i) short-run beliefs such as intentions to contracept; (ii) long-term fertility outcomes, such as the timing and total number of births. To measure the short run causal impact of persuasion, we exploit the fact the Brazil 1991 DHS was fielded in the weeks before, during, and after the Papal visit. We use this fortuitous timing to identify that persuasion significantly reduced individual intentions to contracept by more than 40 percent relative to previsit levels, and increased the frequency of unprotected sex by 30 percent. We measure the long-run causal impacts of persuasion on fertility outcomes using later DHS surveys to conduct an event study analysis on births in a five year window either side of the 1991 Papal visit. Estimating a hazard model of fertility, we find a significant change in births nine months post-visit, corresponding to a 1.6 percent increase in the aggregate birth cohort. Our final set of results examine the very long run impact of persuasion and document the impacts to be on the timing of births rather than on total fertility

Market opportunities for social farms

Although social farming is seen as a successful and innovative sector, social farms face various challenges, among which the need to find additional income required to stay in business. However, assuming that social farm food is considered as having ethical attributes, the research aims at investigating to what extent consumers are conscious of some ethical concerns (problems related to social hardship, social equity, food quality etc.), and whether this will create market opportunities for social farm food. The study area is the province of Pordenone (Italy). The results indicate that conscious consumers could represent an effective market channel also for social farm food, a notable opportunity for farms to improve their socioeconomic performance

Simulation and analysis of solenoidal ion sources

We present a detailed analysis and simulation of solenoidal, magnetically confined electron bombardment ion sources, aimed at molecular beam detection. The aim is to achieve high efficiency for singly ionized species while minimizing multiple ionization. Electron space charge plays a major role and we apply combined ray tracing and finite element simulations to determine the properties of a realistic geometry. The factors controlling electron injection and ion extraction are discussed. The results from simulations are benchmarked against experimental measurements on a prototype source

Noise gates for decoherent quantum circuits

A major problem in exploiting microscopic systems for developing a new technology based on the principles of Quantum Information is the influence of noise which tends to work against the quantum features of such systems. It becomes then crucial to understand how noise affects the evolution of quantum circuits: several techniques have been proposed among which stochastic differential equations (SDEs) can represent a very convenient tool. We show how SDEs naturally map any Markovian noise into a linear operator, which we will call a noise gate, acting on the wave function describing the state of the circuit, and we will discuss some examples. We shall see that these gates can be manipulated like any standard quantum gate, thus simplifying in certain circumstances the task of computing the overall effect of the noise at each stage of the protocol. This approach yields equivalent results to those derived from the Lindblad equation; yet, as we show, it represents a handy and fast tool for performing computations, and moreover, it allows for fast numerical simulations and generalizations to non Markovian noise. In detail we review the depolarizing channel and the generalized amplitude damping channel in terms of this noise gate formalism and show how these techniques can be applied to any quantum circuit.Comment: 10 pages, 4 figures: journal reference added + some typos correcte

Matrix difference equations for the supersymmetric Lie algebra sl(2,1) and the `off-shell' Bethe ansatz

Based on the rational R-matrix of the supersymmetric sl(2,1) matrix difference equations are solved by means of a generalization of the nested algebraic Bethe ansatz. These solutions are shown to be of highest-weight with respect to the underlying graded Lie algebra structure.Comment: 10 pages, LaTex, references and acknowledgements added, spl(2,1) now called sl(2,1

Cross-regulation between Aurora B and Citron kinase controls midbody architecture in cytokinesis.

Cytokinesis culminates in the final separation, or abscission, of the two daughter cells at the end of cell division. Abscission relies on an organelle, the midbody, which forms at the intercellular bridge and is composed of various proteins arranged in a precise stereotypic pattern. The molecular mechanisms controlling midbody organization and function, however, are obscure. Here we show that proper midbody architecture requires cross-regulation between two cell division kinases, Citron kinase (CIT-K) and Aurora B, the kinase component of the chromosomal passenger complex (CPC). CIT-K interacts directly with three CPC components and is required for proper midbody architecture and the orderly arrangement of midbody proteins, including the CPC. In addition, we show that CIT-K promotes Aurora B activity through phosphorylation of the INCENP CPC subunit at the TSS motif. In turn, Aurora B controls CIT-K localization and association with its central spindle partners through phosphorylation of CIT-K's coiled coil domain. Our results identify, for the first time, a cross-regulatory mechanism between two kinases during cytokinesis, which is crucial for establishing the stereotyped organization of midbody proteins.C.M. holds a Cambridge Cancer Centre PhD studentship, which is supported by Cancer Research UK and the MRC. Z.I.B. was supported by a Gwynaeth Pretty PhD studentship and the BlueGnome Molecular Genetics Fund from the Department of Pathology, University of Cambridge, and was also a recipient of a short-term EMBO fellowship and a fellowship from the Cambridge Philosophical Society. G.C. and M.G. are supported by a grant ‘Progetto di Ricerca di Interesse Nazionale’ (PRIN 2012) from the Ministero dell'Istruzione, Università e Ricerca. P.P.D. is the recipient of the Maplethorpe Fellowship from Murray Edwards College, Cambridge, UK.This is the final version of the article. It first appeared from Royal Society Publishing via https://doi.org/10.1098/rsob.16001

Preparation and optimization of TiO2 photoanodes fabricated by pulsed laser deposition for photoelectrochemical water splitting

Quasi-1D TiO2 nanostructures prepared by pulsed laser deposition (PLD) are tested as photoanodes for photoelectrochemical water splitting application and compared with TiO2 nanotube arrays prepared by anodic oxidation. PLD TiO2 films with controlled structure and morphology ranging from compact to vertically oriented or hierarchical porous nanostructures are deposited by ablating a TiO2 target with nanosecond UV laser pulses in the presence of an O2 background atmosphere at different pressures. Thermal treatments at different temperatures are used to transform the so-obtained amorphous systems into nanocrystalline structures (mainly anatase). The effect of film density and thickness is also considered by depositing different amounts of material per unit surface. The morphology and the phase composition of the samples are characterized by SEM and Raman spectroscopy, while the photoelectrochemical water splitting performances are investigated by monitoring the photocurrent generated under illumination in a three-electrode cell. Voltammetric scans and electrochemical impedance spectroscopy analysis were also used to correlate the morphology of PLD samples with their electrochemical properties and their working mechanism in the absence and presence of a light radiation. A clear correlation between structural/morphological properties and photoelectrochemical behavior is found and ideal values of the synthesis parameters are identified, which allow the identification of the optimal quasi-1D nanoporous morphology for water splitting applications. The use of sacrificial organic reagents as hole scavengers was also considered to improve the photoelectrochemical performance of the samples

Online peer-to-peer traffic identification based on complex events processing of traffic event signatures

Peer-to-Peer (P2P) applications are bandwidth-heavy and lead to network congestion. The masquerading nature of P2P traffic makes conventional methods of its identification futile. In order to manage and control P2P traffic efficiently preferably in the network, it is necessary to identify such traffic online and accurately. This paper proposes a technique for online P2P identification based on traffic events signatures. The experimental results show that it is able to identify P2P traffic on the fly with an accuracy of 97.7%, precision of 98% and recall of 99.2%