Assessing symmetry of financial returns series

Testing symmetry of a probability distribution is a common question arising from applications in several fields. Particularly, in the study of observables used in the analysis of stock market index variations, the question of symmetry has not been fully investigated by means of statistical procedures. In this work a distribution-free test statistic Tn for testing symmetry, derived by Einmahl and McKeague, based on the empirical likelihood approach, is used to address the study of symmetry of financial returns. The asymptotic points of the test statistic Tn are also calculated and a procedure for assessing symmetry for the analysis of the returns of stock market indices is presented.Comment: Econophysics paper. 6 pages 2 figure

Crosscorrelation Functions of DS Codes and Probability of Error Evaluations for a Multiple Access Channel

We derive a computationally feasible closed form error expression for probability of error for a small multiple access DS-BPSK system operating in a Rayleigh fading environment. Two properties of the crosscorrelation functions of the DS codes help reduce the number of error probability evaluations required when one considers all possible phase shifts of the users’ codes. Examination of the error rates for different phases of three maximal-length codes reveal that the probability of error is only weakly dependent on the phases

Some aspects of the energy cost linked to the IAQ. Impact of free-cooling and heat recovery in office buildings.

CLIMA 2000 (.1997.BRUSELAS)Increasing air exchange rate to improve IAQ may increase energy consumption, but this increase may be compensated for by strategies such as free cooling and heat recovery. The frame of the proposed paper is the examination of the potential at a regional level (the Iberian peninsula) of the different strategies mentioned above in typical office buildings. Based on a set of reference building morphologies, studies are conducted to evaluate the impact of increasing air ventilation rates for different orientations, quality of the envelope (opaque walls and glazing), operating schedules and indoor set-point temperatures. Then, the impact of the increased air ventilation rates is corrected by introducing the effect of free-cooling, air-to-air heat recovery devices of different types and finally, the combined effect of both energy savings strategies. The research provides Maps allowing: 1. To identify zones when heating or cooling regimes are dominant, in terms of both, peak load conditions and energy requirements. 2. To compare the expected performance of the two energy saving strategies at a certain locality. 3. To compare the potential benefit of applying a given strategy at different localities. 4. To indicate regions of recommendable application of the strategies and the expected energy savings achievable

Use of a biphasic perfusion process based on mild hypothermia for recombinant glucocerebrosidase (GBA) production

The main goal of this study was to develop an innovative CHO-based process for the production of glucocerebrosidase (GBA), an enzyme used for the replacement therapy of Type 1 Gaucher disease. The focus of the present study was on the development of a perfusion process, combining strategies that are commonly used for process optimization: temperature reduction, and supplementation of the culture medium with productivity enhancers, such as short chain fatty acids. The effects of mild hypothermic conditions combined with valeric acid supplementation were first studied in batch shake flasks for two clones (CHO-GBA-36K and CHO-GBA-65P), developed previously using as host the cell lines CHO.K1 (ATCC CCL-61) and CHO.PRO5 (a glycosylation mutant developed by Stanley et al. Cell 6:121, 1975), respectively. A DOE approach was used (Table 1) to select the most promising cultivation conditions to be further applied to a perfusion process. The best performance regarding both cell growth and GBA production was obtained for the CHO-GBA-65P clone under condition [1], at 31ºC with no valeric acid (Table 1). Under this condition, CHO-GBA-65P achieved a maximum qP of 58.4 mU/106 cells/d, which is 4.2 fold higher than qP at the control condition [2] and 2.7 fold higher than the maximum qP obtained for the CHO-GBA-36K clone, which was achieved at 31ºC with 2 mM valeric acid supplementation (condition [3]). Please click Additional Files below to see the full abstract

Patrones de abundancia, bioecología y distribución de la termita neotropical sin soldados Compositermes vindai Scheffrahn, 2013 (Isoptera, Termitidae, Apicotermitinae)

The soldierless Neotropical Apicotermitinae is considered among the less known termite groups and its ecological relevance warrants studies about the biology and diversity of their species. We investigated the presence, distribution and relative abundance of the recently described species Compositermes vindai Scheffrahn, 2013 in natural and anthropized ecosystems of northeastern Argentina. Their nests and populations, as well as their presence inside other Termitidae mounds were examined. A standardized sampling protocol for termites was applied at five sites, with 100 x 2 m transects. Worker morphometric data from the surveyed localities are also reported. C. vindai was found in protected environments with little disturbance as well as in other altered ecosystems. The abundance patterns of C. vindai in the sampled areas varied from rare to intermediate and seemed not to be significantly affected by the environmental changes of the sites due to their land uses. The microhabitats occupied were mainly superficial soil and other Termitidae mounds (Cornitermes cumulans Kollar, 1832; Syntermes obtusus Holmgren, 1911 and Cortaritermes fulviceps Silvestri, 1901). C. vindai subterranean and diffuse nests showed a core surrounding by scattered chambers and tunnels extending into the surrounding soil. The small size colonies comprised workers, brachypterous nymphs and white immature larvae. Winged imagoes or primary reproductives were not found. These new records also extend the distribution of C. vindai across the biomes and ecoregions of the Neotropical ecozone and constitute the first reports of C. vindai from Argentina.Las termitas Neotropicales sin soldados de la subfamilia Apicotermitinae, son consideradas uno de los grupos de isópteros menos conocidos, por lo que resulta importante analizar sus rasgos biológicos y diversidad. Se investigó la presencia, distribución y abundancia relativa de la especie recientemente descripta Compositermes vindai Scheffrahn, 2013 en ecosistemas naturales y antropizados del noreste de Argentina. Se examinaron sus nidos y poblaciones, así como su presencia en los montículos de otras termitas. Se aplicó un protocolo estandarizado de muestreo para isópteros en cinco sitios, con transectas de 100 x 2 m. También se registraron datos morfométricos de obreras. C. vindai fue detectada en ambientes protegidos poco perturbados, así como en otros ecosistemas alterados. Los patrones de abundancia de C. vindai en estas áreas variaron de rara a intermedia y la especie pareció no ser afectada de manera significativa por los cambios ambientales derivados de diferentes usos de la tierra. Los microhábitats ocupados fueron principalmente suelo superficial y montículos de otras Termitidae (Cornitermes cumulans Kollar, 1832; Syntermes obtusus Holmgren, 1911 y Cortaritermes fulviceps Silvestri, 1901). Los nidos subterráneos y difusos de C. vindai mostraron un núcleo rodeado por cámaras dispersas y túneles que se extendían en el suelo circundante. Las pequeñas colonias estuvieron compuestas por obreras, ninfas braquípteras e inmaduros. No se hallaron individuos alados ni reproductores primarios. Estos nuevos registros extienden la distribución de C. vindai a otros biomas y ecorregiones de la ecozona Neotropical y constituyen los primeros hallazgos de C. vindai para Argentina