The fine structure of asset returns: an empirical investigation

We investigate the importance of diffusion and jumps in a new model for asset returns. In contrast to standard models, we allow for jump components displaying finite or infinite activity and variation. Empirical investigations of time series indicate that index dynamics are devoid of a diffusion component, which may be present in the dynamics of individual stocks. This leads to the conjecture, confirmed on options data, that the risk-neutral process should be free of a diffusion component. We conclude that the statistical and risk-neutral processes for equity prices are pure jump processes of infinite activity and finite variation

Quenching of Star Formation

In the last decade we have seen an enormous increase in the size and quality of spectroscopic galaxy surveys, both at low and high redshift. New statistical techniques to analyse large portions of galaxy spectra are now finding favour over traditional index based methods. Here we will review a new robust and iterative Principal Component Analysis (PCA) algorithm, which solves several common issues with classic PCA. Application to the 4000AA break region of galaxies in the VIMOS VLT Deep Survey (VVDS) and Sloan Digital Sky Survey (SDSS) gives new high signal-to-noise ratio spectral indices easily interpretable in terms of recent star formation history. In particular, we identify a sample of post-starburst galaxies at z~0.7 and z~0.07. We quantify for the first time the importance of post-starburst galaxies, consistent with being descendants of gas-rich major mergers, for building the red sequence. Finally, we present a comparison with new low and high redshift "mock spectroscopic surveys" derived from a Millennium Run semi-analytic model.Comment: 7 pages, 3 figures. Conference proceedings in "Classification and Discovery in Large Astronomical Surveys", 2008, C.A.L. Bailer-Jones (ed.

Control of Disturbing Loads in Residential and Commercial Buildings via Geometric Algebra

Many definitions have been formulated to represent nonactive power for distorted voltages and currents in electronic and electrical systems. Unfortunately, no single universally suitable representation has been accepted as a prototype for this power component. This paper defines a nonactive power multivector from the most advanced multivectorial power theory based on the geometric algebra (GA). The new concept can have more importance on harmonic loads compensation, identification, and metering, between other applications. Likewise, this paper is concerned with a pioneering method for the compensation of disturbing loads. In this way, we propose a multivectorial relative quality index   associated with the power multivector. It can be assumed as a new index for power quality evaluation, harmonic sources detection, and power factor improvement in residential and commercial buildings. The proposed method consists of a single-point strategy based of a comparison among different relative quality index multivectors, which may be measured at the different loads on the same metering point. The comparison can give pieces of information with magnitude, direction, and sense on the presence of disturbing loads. A numerical example is used to illustrate the clear capabilities of the suggested approach

Culture portability from origin to destination country: The gender division of domestic work among migrants in Italy

Background: The relative importance of a cultural component in the gender division of unpaid labour is still debated. Objective: Drawing on the epidemiological approach to the study of culture, we investigate the cultural component of gender inequality by examining whether gender asymmetries in housework and childcare in families with a migrant background relate to gender equity in the country of origin. Methods: Through multilevel models based on microlevel data (Istat SCIF survey), we examine the extent to which the division of household labour between immigrant partners living in Italy relates to gender equity in their origin country, proxied by the Global Gender Gap Index. We further analyse the changing importance of gender equity in the country of origin at different lengths of stay in the destination country. Conclusions: Immigrants from more (less) gender-equal countries display greater (lower) equality in the division of routine housework and childcare activities. However, gender equity in the origin country loses its importance for couples living in the destination country for a longer time. These findings point to a significant contribution of culture of origin to gender inequality in the intra-couple division of unpaid labour. Yet nonnegligible differences exist between specific housework and childcare tasks and depending on the time spent in the hosting country. Contribution: Our study contributes to the literature on gender inequalities by providing new evidence on the relationship between culture of origin and the division of specific housework and childcare tasks in families with a migrant background

The continuous rise of bulges out of galactic disks

(abridged) This study revolves around dmB, a new distance- and extinction-independent measure of the contribution by stellar populations older than 9 Gyr to the mean r-band surface brightness of the bulge component in 135 late-type galaxies (LTGs) from the CALIFA survey, spanning a range of 2.6 dex and 3 dex in total and bulge stellar mass (M*T~10^(8.9-11.5) M_solar and M*B~10^(8.3-11.3) M_solar, respectively). The main insight from this study is that LTG bulges form a continuous sequence of increasing dmB with increasing M*T, M*B, stellar mass surface density S* and mass-weighted age and metallicity: high-dmB bulges are the oldest, densest and most massive ones, and vice versa. Furthermore, we find that the bulge-to-disk age and metallicity contrast, as well as the bulge-to-disk mass ratio increase with M*T, raising from, respectively, ~0 Gyr, 0 dex and 0.25 to ~3 Gyr, ~0.3 dex and 0.67 across the mass range covered by our sample. Whereas gas excitation in lower-mass bulges is invariably dominated by star formation (SF), LINER- and Seyfert-specific emission-line ratios were exclusively documented in high-mass, high-S* bulges. The continuity both in the properties of LTG bulges themselves and in their age and metallicity contrast to their parent disks suggests that these components evolve alongside in a concurrent process that leads to a continuum of physical and evolutionary characteristics. Our results are consistent with a picture where bulge growth in LTGs is driven by a superposition of quick-early and slow-secular processes, the relative importance of which increases with M*T. These processes, which presumably combine in situ SF in the bulge and inward migration of material from the disk, are expected to lead to a non-homologous radial growth of S* and a trend for an increasing Sersic index with increasing galaxy mass.Comment: 24 pages, accepted for publication in A&

Assessing the transport development of the European Union countries

In their previous publication, the authors proposed to assess the transport development of any territory (but mainly the territories of the world’s countries) according to the following three components: transportization level of a territory, transport internationalization level of a territory and quality of transport in a territory. The authors assessed three components of the transport development of a territory each separately, including them in further empirical analysis. In the course of the authors’ empirical research, it became necessary to improve the methodology for assessing the transport development of a territory. The purpose of this study is to develop a single tool for measuring the transport development of a territory – an index – and to test it on the example of the European Union countries. Methods used in the study: monographic method, logical analysis and synthesis of the conceptual essence of the phenomenon ‘transport development of a territory’, index method – a quantitative technique for assessing the transport development of a territory based on the minimum and maximum values. The information base of the study is the data of the Global Competitiveness Report, as well as data from GlobalEconomy.com and the World Factbook for the EU countries. As a result of the study, the authors developed a new Territory Transport Development Index (TTDI), which includes not three, but four components: transportization level of a territory, transport internationalization level of a territory, quality of the transport infrastructure in a territory, efficiency of the transport services in a territory. These four components of the Index developed by the authors differ from the previously proposed components of the transport development of a territory. This difference is determined by the results of study carried out by researchers of the Riga Technical University (RTU), which confirm the importance of transport infrastructure in the use of a territory’s resources, as well as the results of other comparative studies on the transport infrastructure of the EU countries. Thus, the third component (quality of transport in a territory) was divided into two separate components: quality of the transport infrastructure in a territory and efficiency of the transport services in a territory, including additional indicators in the first of them. The authors tested the new Index by assessing the European Union countries and comparing them both in general transport development and separately in its different aspectspublishersversionPeer reviewe