Neuro-Controllers, scalability and adaptation

A Layered Evolution (LE) paradigm based method for the generation of a neuron-controller is developed and verified through simulations and experimentally. It is intended to solve scalability issues in systems with many behavioral modules. Each and every module is a genetically evolved neuro-controller specialized in performing a different task. The main goal is to reach a combination of different basic behavioral elements using different artificial neural-network paradigms concerning mobile robot navigation in an unknown environment. The obtained controller is evaluated over different scenarios in a structured environment, ranging from a detailed simulation model to a real experiment. Finally most important implies are shown through several focuses

Neuro-Controllers, scalability and adaptation

A Layered Evolution (LE) paradigm based method for the generation of a neuron-controller is developed and verified through simulations and experimentally. It is intended to solve scalability issues in systems with many behavioral modules. Each and every module is a genetically evolved neuro-controller specialized in performing a different task. The main goal is to reach a combination of different basic behavioral elements using different artificial neural-network paradigms concerning mobile robot navigation in an unknown environment. The obtained controller is evaluated over different scenarios in a structured environment, ranging from a detailed simulation model to a real experiment. Finally most important implies are shown through several focuses.Red de Universidades con Carreras en Informática (RedUNCI

Intertidal zone particulate organic carbon redistribution by low-tide rainfall

We present field data and data from the literature to highlight the effects of low-tide rainfall on particulate organic carbon (POC) redistribution in intertidal landscapes. The POC exchanges reported from disparate but related studies were standardized to a storm-induced exchange rate (gPOC m⁻² mmRain⁻¹) and compared. Results show that these intertidal areas have a characteristic response to rainfall with an average flux of 0.040 ± 0.038 gPOC m⁻² mmRain⁻¹. Further, low-tide rainfall can entrain and redistribute 7–54% of annual sedimentary POC accumulation, or 12–75% of annual POC export, based on current outwelling assessments. Finally, we provide a conceptual model describing the variability of rainfall-driven POC exchange through the hierarchical structure of intertidal landscapes and how observations of POC flux can be expected to change across the intertidal landscape. This information should be used to guide sampling strategies for continued intertidal zone rainfall work.This is the publisher’s final pdf. The article is copyrighted by the Association for the Sciences of Limnology and Oceanography (ASLO) and published by John Wiley & Sons, Ltd. It can be found at: http://www.aslo.org/lo/index.htm

Particulate organic matter export by two contrasting small mountainous rivers from the Pacific Northwest, U.S.A.

We investigated the export of particulate organic matter (POM) to the ocean by two contrasting small, mountainous rivers, the Umpqua and Eel Rivers, by collecting suspended sediment samples over a range of discharges and analyzing them for a variety of constituents, including organic carbon, nitrogen, biomarkers with distinct biochemical sources, and isotopic compositions (δ¹³C and Δ¹⁴C). Concentrations of all measured constituents in both rivers increased as a function of discharge, resulting in their export being dominated by short-lived, wintertime high-discharge events. In the Umpqua River, marked compositional contrasts between low- and high-discharge conditions were consistent with a shift in the provenance of POM from biogenic sources dominated by non-vascular plant sources at low flows to contributions from vascular plant sources of moderate ¹⁴C ages (~300 years before present) dominating at high flows. In contrast, POM from the Eel River, which was highly diluted by mineral sediment at all discharges, had significant contributions from petrogenic sources and displayed lower concentrations of recognizable biomarkers. Both rivers had comparable yields of biogenic POM, which appeared to be moderately degraded and originated primarily from surface soils in erosion prone areas of the watersheds. While tectonic/geologic differences help explain the contrasts in sediment and petrogenic POM yields between the two watersheds, ecological factors such as vegetation coverage, productivity, and soil carbon are more important in influencing the composition of biogenic POM mobilized from these systems.Keywords: Oregon Coast Range, Northern California, Mendocino triple junction, Eel River, Efffective discharge, Carbon, Continental shelf, Debris flow, United States, Sediment transpor

Neuro-Controllers, scalability and adaptation

A Layered Evolution (LE) paradigm based method for the generation of a neuron-controller is developed and verified through simulations and experimentally. It is intended to solve scalability issues in systems with many behavioral modules. Each and every module is a genetically evolved neuro-controller specialized in performing a different task. The main goal is to reach a combination of different basic behavioral elements using different artificial neural-network paradigms concerning mobile robot navigation in an unknown environment. The obtained controller is evaluated over different scenarios in a structured environment, ranging from a detailed simulation model to a real experiment. Finally most important implies are shown through several focuses.Red de Universidades con Carreras en Informática (RedUNCI

Effects of antecedent hydrologic conditions, time dependence, and climate cycles on the suspended sediment load of the Salinas River, California

See pdf for abstract.Keywords: Non-stationary Effective discharge, Suspended sediment, El Niño Southern Oscillation, Small mountainous rivers, Arid river

The effect of El Niño Southern Oscillation cycles on the decadal scale suspended sediment behavior of a coastal dry-summer subtropical catchment

Rivers display temporal dependence in suspended sediment–water discharge relationships. Although most work has focused on multi-decadal trends, river sediment behavior often displays sub-decadal scale fluctuations that have received little attention. The objectives of this study were to identify inter-annual to decadal scale fluctuations in the suspended sediment–discharge relationship of a dry-summer subtropical river, infer the mechanisms behind these fluctuations, and examine the role of El Niño Southern Oscillation climate cycles. The Salinas River (California) is a moderate sized (11,000 km²), coastal dry-summer subtropical catchment with a mean discharge (Q[subscript mean]) of 11.6 m³ s⁻¹. This watershed is located at the northern most extent of the Pacific coastal North America region that experiences increased storm frequency during El Niño years. Event to inter-annual scale suspended sediment behavior in this system was known to be influenced by antecedent hydrologic conditions, whereby previous hydrologic activity regulates the suspended sediment concentration–water discharge relationship. Fine and sand suspended sediment in the lower Salinas River exhibited persistent, decadal scale periods of positive and negative discharge corrected concentrations. The decadal scale variability in suspended sediment behavior was influenced by inter-annual to decadal scale fluctuations in hydrologic characteristics, including: elapsed time since small (~0.1 × Q[subscript mean]), and moderate (~10 × Q[subscript mean]) threshold discharge values, the number of preceding days that low/no flow occurred, and annual water yield. El Niño climatic activity was found to have little effect on decadal-scale fluctuations in the fine suspended sediment–discharge relationship due to low or no effect on the frequency of moderate to low discharge magnitudes, annual precipitation, and water yield. However, sand concentrations generally increased in El Niño years due to the increased frequency of moderate to high magnitude discharge events, which generally increase sand supply.Keywords: Non-stationarity, Suspended sediment, El Niño Southern Oscillation, Long-term memory, Arid river

Birth weight and blood lipid levels in Spanish adolescents: Influence of selected APOE, APOC3 and PPARgamma2 gene polymorphisms. The AVENA Study

Es reproducción del documento publicado en http://dx.doi.org/10.1186/1471-2350-9-98Background: There is increasing evidence indicating that genes involved in certain metabolic processes of cardiovascular diseases may be of particular influence in people with low body weight at birth. We examined whether the apolipoprotein (APO) E, APOC3 and the peroxisome proliferator-activated receptor-gamma-2 (PPAR gamma 2) polymorphisms influence the association between low birth weight and blood lipid levels in healthy adolescents aged 13-18.5 years. Methods: A cross-sectional study of 502 Spanish adolescents born at term was conducted. Total (TC) and high density lipoprotein cholesterol (HDLc), triglycerides (TG), apolipoprotein (apo) A and B, and lipoprotein(a) [ Lp(a)] were measured. Low density lipoprotein cholesterol (LDLc), TC-HDLc, TC/HDLc and apoB/apoA were calculated. Results: Low birth weight was associated with higher levels of TC, LDLc, apoB, Lp(a), TC-HDLc, TC/HDLc and apoB/apoA in males with the APOE epsilon 3 epsilon 4 genotype, whereas in females, it was associated with lower HDLc and higher TG levels. In males with the APOC3 S1/S2 genotype, low birth weight was associated with lower apoA and higher Lp(a), yet this association was not observed in females. There were no associations between low birth weight and blood lipids in any of the PPAR gamma 2 genotypes. Conclusion: The results indicate that low birth weight has a deleterious influence on lipid profile particularly in adolescents with the APOE epsilon 3/epsilon 4 genotype. These findings suggest that intrauterine environment interact with the genetic background affecting the lipid profile in later life.Instituto de Salud Carlos III (FIS PI021830), the Spanish Ministry of Health, FEDER-FSE funds FIS n 00/0015, CSD grants 05/UPB32/0, 109/UPB31/03 and 13/UPB20/04, Ministerio de Educación (AP-2004-2745; EX2007-1124

Trends in socioeconomic inequalities in mortality in small areas of 33 Spanish cities

Background: In Spain, several ecological studies have analyzed trends in socioeconomic inequalities in mortality from all causes in urban areas over time. However, the results of these studies are quite heterogeneous finding, in general, that inequalities decreased, or remained stable. Therefore, the objectives of this study are: (1) to identify trends in geographical inequalities in all-cause mortality in the census tracts of 33 Spanish cities between the two periods 1996–1998 and 2005–2007; (2) to analyse trends in the relationship between these geographical inequalities and socioeconomic deprivation; and (3) to obtain an overall measure which summarises the relationship found in each one of the cities and to analyse its variation over time. Methods: Ecological study of trends with 2 cross-sectional cuts, corresponding to two periods of analysis: 1996–1998 and 2005–2007. Units of analysis were census tracts of the 33 Spanish cities. A deprivation index calculated for each census tracts in all cities was included as a covariate. A Bayesian hierarchical model was used to estimate smoothed Standardized Mortality Ratios (sSMR) by each census tract and period. The geographical distribution of these sSMR was represented using maps of septiles. In addition, two different Bayesian hierarchical models were used to measure the association between all-cause mortality and the deprivation index in each city and period, and by sex: (1) including the association as a fixed effect for each city; (2) including the association as random effects. In both models the data spatial structure can be controlled within each city. The association in each city was measured using relative risks (RR) and their 95 % credible intervals (95 % CI). Results: For most cities and in both sexes, mortality rates decline over time. For women, the mortality and deprivation patterns are similar in the first period, while in the second they are different for most cities. For men, RRs remain stable over time in 29 cities, in 3 diminish and in 1 increase. For women, in 30 cities, a non-significant change over time in RR is observed. However, in 4 cities RR diminishes. In overall terms, inequalities decrease (with a probability of 0.9) in both men (RR = 1.13, 95 % CI = 1.12–1.15 in the 1st period; RR = 1.11, 95 % CI = 1.09–1.13 in the 2nd period) and women (RR = 1.07, 95 % CI = 1.05–1.08 in the 1st period; RR = 1.04, 95 % CI = 1.02–1.06 in the 2nd period). Conclusions: In the future, it is important to conduct further trend studies, allowing to monitoring trends in socioeconomic inequalities in mortality and to identify (among other things) temporal factors that may influence these inequalities.This article was partially funded by Plan Nacional de I + D + I 2008–2011 and Instituto de Salud Carlos III (ISCIII) –Subdirección General de Evaluación y Fomento de la Investigación- (Award numbers: PI081488, PI081978, PI080367, PI08/1017, PI080330, P08/0142, PI081785, PI080662, PI081713, PI081058, PI081340, PI080803, PI126/08), Fundación Canaria de Investigación Sanitaria FUNCIS 84/07 and by CIBER Epidemiología y Salud Pública (CIBERESP)