Enumeration of saturated chains in Dyck lattices

We determine a general formula to compute the number of saturated chains in Dyck lattices, and we apply it to find the number of saturated chains of length 2 and 3. We also compute what we call the Hasse index (of order 2 and 3) of Dyck lattices, which is the ratio between the total number of saturated chains (of length 2 and 3) and the cardinality of the underlying poset.Comment: 9 page

Gravitational waves emitted by solar-type stars excited by orbiting planets

The possibility of exciting the g-modes of a solar-type star as a consequence of the gravitational interaction with a close companion (a planet or a brown dwarf) is studied by a perturbative approach. The amplitude of the emitted gravitational wave is computed and compared with the quadrupole emission of the system, showing that in some cases it can be considerably larger. The effects of radiation reaction are considered to evaluate the timescale of the emission process, and a Roche lobe analysis is used to establish the region where the companion can orbit without being disrupted by tidal interactions with the star.Comment: 19 pages, 1 figure, submitted to Phys. Rev. D. Typo in formula (5.4) correcte

Deriving CGE Baselines from Macro-economic Projections

Quantitative policy analysts are usually confronted with the problem to derive a base-line scenario that reflects the most likely state of an economy in a future year. The methods used in practice to derive such a base-line scenarios are heterogeneous and range from the usage of the last observable year to complete and consistent estimation procedures. In the case of general equilibrium (CGE) analyses, the Scenar2020 project (European Commission 2006a) is one example how projections of macro-economic indicators (exogenous drivers) are used to construct the base-line as a model scenario: Starting from a calibrated version, exogenous variables are modified until macro-economic projections are met. However, numerous projections refer to economic indicators which are endogenous variables within the CGE framework, such as gross domestic product (GDP), market prices, or produced quantities. To investigate methods that allow integrating projections for endogenous CGE variables is the main topic of this study. Our starting point is the work by Arndt et al (2002), where entropy-based (Golan et al 1996) techniques are employed for the estimation of behavioural parameters by fitting a CGE model to time series on endogenous variables. Following this concept, we investigate a method to fit a CGE´s parameters and endogenous variables to market- and macro-economic projections from major research institutes.general equilibrium model, baseline construction, parameter estimation, macro-economic projections, Research Methods/ Statistical Methods,

Gravitational waves emitted by extrasolar planetary systems

In this paper we consider the Extra-solar Planetary Systems recently discovered in our Galaxy as potential sources of gravitational waves. We estimate the frequency and characteristic amplitude of the radiation they emit due to the orbital motion, using the quadrupole formalism. In addition, we check whether the conditions needed for the resonant excitation of the f- and g-modes of the central star can be fulfilled. By a Roche-lobe analysis, we show that there could exist systems in which the low-order g-modes could be excited, although this does not happen in the systems discovered up to now.Comment: 14 pages, 5 figures. Accepted for publication on International Journal of Modern Physics D. Table 6 and minor typos correcte

Estimation and modelling impacts of Pillar 2 measures on the agricultural sector: Workshop proceedings

This report presents a synthesis of the workshop, summarising the presentations and discussions in the different sessions. The report is organized following the structure of the workshop. The first session of the workshop sets the scene and introduces the main topic at stake. The second session aims at providing current studies estimating the impacts of Pillar 2 measures on agricultural productivity and other main factors (e.g., growth, employment). The third session provides an overview of existing modelling approaches, general and partial equilibrium, to simulate effects of shocks in Pillar 2 payments on the EU agricultural sector. Finally, the fourth session concludes and draws some key messages on how the JRC shall proceed in future efforts on the topic.JRC.D.4-Economics of Agricultur

Regional Social Accounting Matrices for the EU27 (SAMNUTS2)

Agricultural polices in the EU are increasingly targeting not only the agricultural sector but also other economic branches. The indirect effects of these policies, as the rural development ones, might be as important as the direct ones, mainly on factor markets as labour. In addition, in order to better scale the adopted agricultural measures, policy makers are devoting more attention to the regionalized impacts of these policies. For these reasons, a pure partial-equilibrium agricultural model is not enough to account the effects of the EU agricultural policies. The development of regionalized Computable General Equilibrium models and the linkages with already developed regionalized agricultural partial equilibrium models is a fundamental step for agricultural economists. The greatest challenge to build a regional general equilibrium model for all EU27 NUTS2 regions is the database construction. This work show the main steps needed to construct such a database, called SAMNUTS2JRC.J.4-Agriculture and Life Sciences in the Econom

An Inventory of Datasets for the Compilation of Regional Social Accounting Matrices for the EU

Due to the ever-increasing demand for model-based analyses of regional development policies in a multi-sector context, in 2009 the Institute for Prospective Technological Studies (IPTS) launched a project on the compilation of regional Social Accounting Matrices (SAM) for the NUTS2 regions of the EU (IOTNUTS2). The SAMs cover the time span between 2000 and 2005. This database shall permit general equilibrium analyses of policies like reforestation programmes, the promotion of investment in agro-tourism or environmental services, and the support for the production of renewable energy by farming enterprises, and, more generally, it will permit the evaluation of the rural development pillar of the European Common Agricultural Policy. Such measures primarily target the agricultural sector, but are likely to have an impact on other economic sectors and aggregate regional income, depending on the regional economic structure and the dominance of agriculture. Addressing regional heterogeneity requires multi-sector data on a sub-national scale. Such datasets are usually not sufficiently detailed, if available at all, which gave rise to numerous non-survey methods to generate regional Input-Output tables based on combinations of available regional indicators and national datasets (e.g. Location Quotients, GRIT methods). One particular challenge encountered during the IOTNUTS2 project was the high level of sectoral aggregation in regional branch accounts provided by ESTAT, where agriculture, forestry, and fisheries are merged for example. Given the interest in spillover effects of dominantly agricultural policies, more detailed information was required. Therefore, statistical organisations of the 27 EU Member States were contacted and the results of previous projects on regional databases were screened. This paper gives an overview of the compiled inventory on regional datasets for EU27, starting with the target structure of the database and the available national and regional datasets from ESTAT. Based on this, we discuss the datasets obtained from national statistical departments (NSO) and from previous projects with comparable aims. In general, we achieved a significant informational gain in comparison to the exclusive use of ESTAT datasets for several Member States although for some (i.e. Bulgaria) it was not as large as initially expected. Furthermore, we used the obtained NSO data to test the reliability of non-survey methods for the combination of national and regional datasets. It appeared that forestry, mining/quarrying, and fuel industries in particular displayed substantial deviations between derived indicators and those obtained from NSO, namely intermediate demand and gross output. For other branches, information could either be obtained (e.g. agriculture) or derived indicators proved to be close to the NSO values (most service sectors). In general, we conclude that for the majority of economic sectors considered, non-survey methods can generate reliable substitutes for otherwise collected indicators, but not for some critical branches which are usually concentrated in some regions and may dominate the regional economic structure (forestry, mining, fisheries). This result can be helpful for future projects with comparable objectives as we suggest that instead of attempting to sample economy-wide datasets, a focus on the mentioned critical sectors would provide higher marginal informational gains. The data collected from all the different sources are firstly utilized to populate national Input-Output tables for the EU 27 Member States. These matrices are then balanced following standard cross-entropy methods. These tables, with the suitable level of disaggregation, could be utilized as the starting point to update the EU Input-Output tables that IPTS provided to the GTAP Consortium.JRC.J.5-Agriculture and Life Sciences in the Econom

A generalization of the "probléme des rencontres"

In this paper, we study a generalization of the classical \emph{probl\'eme des rencontres} (\emph{problem of coincidences}), consisting in the enumeration of all permutations \pi \in \SS_n with $k$ fixed points, and, in particular, in the enumeration of all permutations \pi \in \SS_n with no fixed points (derangements). Specifically, we study this problem for the permutations of the $n+m$ symbols $1$, $2$, \ldots, $n$, $v_1$, $v_2$, \ldots, $v_m$, where $v_i \not\in\{1,2,\ldots,n\}$ for every $i=1,2,\ldots,m$. In this way, we obtain a generalization of the derangement numbers, the rencontres numbers and the rencontres polynomials. For these numbers and polynomials, we obtain the exponential generating series, some recurrences and representations, and several combinatorial identities. Moreover, we obtain the expectation and the variance of the number of fixed points in a random permutation of the considered kind. Finally, we obtain some asymptotic formulas for the generalized rencontres numbers and the generalized derangement numbers