Luminosity function, sizes and FR dichotomy of radio-loud AGN

The radio luminosity function (RLF) of radio galaxies and radio-loud quasars is often modelled as a broken power-law. The break luminosity is close to the dividing line between the two Fanaroff-Riley (FR) morphological classes for the large-scale radio structure of these objects. We use an analytical model for the luminosity and size evolution of FRII-type objects together with a simple prescription for FRI-type sources to construct the RLF. We postulate that all sources start out with an FRII-type morphology. Weaker jets subsequently disrupt within the quasi-constant density cores of their host galaxies and develop turbulent lobes of type FRI. With this model we recover the slopes of the power laws and the break luminosity of the RLF determined from observations. The rate at which AGN with jets of jet power $Q$ appear in the universe is found to be proportional to $Q^{-1.6}$. The model also roughly predicts the distribution of the radio lobe sizes for FRII-type objects, if the radio luminosity of the turbulent jets drops significantly at the point of disruption. We show that our model is consistent with recent ideas of two distinct accretion modes in jet-producing AGN, if radiative efficiency of the accretion process is correlated with jet power.Comment: 13 pages, 1 figure, accepted by MNRA

Maximal inequalities for fractional L\'evy and related processes

In this paper we study processes which are constructed by a convolution of a deterministic kernel with a martingale. A special emphasis is put on the case where the driving martingale is a centred L\'evy process, which covers the popular class of fractional L\'evy processes. As a main result we show that, under appropriate assumptions on the kernel and the martingale, the maximum process of the corresponding `convoluted martingale' is $p$-integrable and we derive maximal inequalities in terms of the kernel and of the moments of the driving martingale

The Thermodynamic Limit of Quantum Coulomb Systems: A New Approach

We present two recent works on the thermodynamic limit of quantum Coulomb systems, in which we provided a general method allowing to show the existence of the limit for many different models.Comment: Talk given by M.L. at QMath10, 10th Quantum Mathematics International Conference, Moeciu (Romania) in September 200

The production and diffusion of policy knowledge

"The published works of the International Food Policy Research Institute (IFPRI) represent the most immediate and tangible measure of the new policy-related knowledge attributable to the institute, its staff, and research partners. This study provides a quantitative assessment of the number, nature, form, and use of IFPRI's published products since 1979 and compares and contrasts that with the publication performance of several similar agencies, including the economics and social sciences programs of the Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT) and the International Rice Research Institute (IRRI) respectively, the Australian Bureau of Agricultural and Resource Economics (ABARE), the Bangladesh Institute for Development Studies (BIDS), and the now defunct Stanford University Food Research Institute (SFRI). Overall, IFPRI's circulated output is extensive, published not only in a broad portfolio of leading scholarly journals, but also in a wide range of books, technical reports, and extension documents. The amount of published output has tended to increase throughout IFPRI's history, and it continues to do so. Going beyond counting and classifying IFPRI's published record, we report the results of a bibliometric assessment of IFPRI and the comparison institutes for the period 1981–96 using the publication and citation performance details recorded in the Institute for Scientific Information's (ISI) Science Citation Index and Social Science Citation Index data bases. Citations to published literature are not indicative of an impact on policy or the economy generally but on further research and analysis. An analysis of coauthorship patterns provides an indication of impact too (more directly through the conduct of joint research), as well as indications of the way the research is carried out. Our analysis reveals the role IFPRI plays as a knowledge intermediary between the scholarly community and policy clienteles, but that a high proportion of its research collaborations leading to formal publications (and especially publications in the leading journals covered in ISI's data bases) involve researchers in advanced agencies. This partly reflects the limited capacity to perform food policy research in many developing countries — itself a reflection of local priorities for education and limited, long-term international support to increase scientific capacity in developing countries — and also underscores the role IFPRI could, and arguably should, play in redressing this state of affairs." Authors' AbstractInternational Food Policy Research Institute History ,Research institutes Evaluation ,Communication in learning and scholarship ,Bibliometrics ,Information science Statistical methods ,Knowledge management ,International Food Policy Research Institute Communications systems Evaluation ,Food policy Research ,

Extracting the Temperature of Hot Carriers in Time- and Angle-Resolved Photoemission

The interaction of light with a material's electronic system creates an out-of-equilibrium (non-thermal) distribution of optically excited electrons. Non-equilibrium dynamics relaxes this distribution on an ultrafast timescale to a hot Fermi-Dirac distribution with a well-defined temperature. The advent of time- and angle-resolved photoemission spectroscopy (TR-ARPES) experiments has made it possible to track the decay of the temperature of the excited hot electrons in selected states in the Brillouin zone, and to reveal their cooling in unprecedented detail in a variety of emerging materials. It is, however, not a straightforward task to determine the temperature with high accuracy. This is mainly attributable to an a priori unknown position of the Fermi level and the fact that the shape of the Fermi edge can be severely perturbed when the state in question is crossing the Fermi energy. Here, we introduce a method that circumvents these difficulties and accurately extracts both the temperature and the position of the Fermi level for a hot carrier distribution by tracking the occupation statistics of the carriers measured in a TR-ARPES experiment.Comment: 17 pages, 5 figure