Heuristic based evolution for the coordination of autonomous vehicles in the absence of speed lanes

The current state of the art in the planning and coordination of autonomous vehicles is based upon the presence of speed lanes. In a traffic scenario where there is a large diversity between vehicles the removal of speed lanes can generate a significantly higher traffic bandwidth. Vehicle navigation in such unorganized traffic is considered. An evolutionary based trajectory planning technique has the advantages of making driving efficient and safe, however it also has to surpass the hurdle of computational cost. In this paper, we propose a real time genetic algorithm with Bezier curves for trajectory planning. The main contribution is the integration of vehicle following and overtaking behaviour for general traffic as heuristics for the coordination between vehicles. The resultant coordination strategy is fast and near-optimal. As the vehicles move, uncertainties may arise which are constantly adapted to, and may even lead to either the cancellation of an overtaking procedure or the initiation of one. Higher level planning is performed by Dijkstra's algorithm which indicates the route to be followed by the vehicle in a road network. Re-planning is carried out when a road blockage or obstacle is detected. Experimental results confirm the success of the algorithm subject to optimal high and low-level planning, re-planning and overtaking.

A radial basis function network classifier to maximise leave-one-out mutual information

tWe develop an orthogonal forward selection (OFS) approach to construct radial basis function (RBF)network classifiers for two-class problems. Our approach integrates several concepts in probabilisticmodelling, including cross validation, mutual information and Bayesian hyperparameter fitting. At eachstage of the OFS procedure, one model term is selected by maximising the leave-one-out mutual infor-mation (LOOMI) between the classifier’s predicted class labels and the true class labels. We derive theformula of LOOMI within the OFS framework so that the LOOMI can be evaluated efficiently for modelterm selection. Furthermore, a Bayesian procedure of hyperparameter fitting is also integrated into theeach stage of the OFS to infer the l2-norm based local regularisation parameter from the data. Since eachforward stage is effectively fitting of a one-variable model, this task is very fast. The classifier construc-tion procedure is automatically terminated without the need of using additional stopping criterion toyield very sparse RBF classifiers with excellent classification generalisation performance, which is par-ticular useful for the noisy data sets with highly overlapping class distribution. A number of benchmarkexamples are employed to demonstrate the effectiveness of our proposed approach.

Quantifying sources of inter-model diversity in the cloud albedo effect

There is large diversity in simulated aerosol forcing among models that participated in the fifth Coupled Model Intercomparison Project (CMIP5), particularly related to aerosol interactions with clouds. Here we use the reported model data and fitted aerosol-cloud relations to separate the main sources of inter-model diversity in the magnitude of the cloud albedo effect. There is large diversity in the global load and spatial distribution of sulfate aerosol, as well as in global-mean cloud-top effective radius. The use of different parameterizations of aerosol-cloud interactions makes the largest contribution to diversity in modeled radiative forcing (up to -39%, +48% about the mean estimate). Uncertainty in pre-industrial sulfate load also makes a substantial contribution (-15%, +61% about the mean estimate), with smaller contributions from inter-model differences in the historical change in sulfate load and in mean cloud fraction.

Do turning biases by the 7-spot ladybird, Coccinella septempunctata, increase their foraging efficiency?

The hypothesis that foraging male and female Coccinella septempunctata L. would exhibit a turning bias when walking along a branched linear wire in a Y-maze was tested. Individuals were placed repeatedly in the maze. Approximately 45% of all individuals tested displayed significant turning biases, with a similar number of individuals biased to the left and right. In the maze right-handed individuals turned right at 84.4% of turns and the left-handed individuals turned left at 80.2% of turns. A model of the searching efficiency of C. septempunctata in dichotomous branched environments showed that model coccinellids with greater turning biases discovered a higher proportion of the plant for a given number of searches than those with no bias. A modification of the model to investigate foraging efficiency, by calculating the mean time taken by individuals to find randomly distributed aphid patches, suggested that on four different sizes of plants, with a variety of aphid patch densities, implementing a turning bias was a significantly more efficient foraging strategy than no bias. In general the benefits to foraging of implementing a turning bias increased with the degree of the bias. It may be beneficial for individuals in highly complex branched environments to have a turning bias slightly lower than 100% in order to benefit from increased foraging efficiency without walking in circles. Foraging bias benefits increased with increasing plant size and decreasing aphid density. In comparisons of two different plant morphologies, one with a straight stem and side branches and one with a symmetrically branched morphology, there were few significant differences in the effects of turning biases on foraging efficiency between morphologies

Stigma and risky behaviors among male clients of sex workers in the UK in 2001

This paper builds on existing theoretical work on sex markets (Della Giusta, Di Tommaso, and Strøm, 2009a). Using data from the British Sexual Attitudes Survey, we aim to replicate the analysis of the demand for paid sex previously conducted for the US (Della Giusta, Di Tommaso, Shima and Strøm, 2009b). We want to test formally the effect of attitudes, risky behaviors and personal characteristics on the demand for paid sex. Findings from empirical studies of clients suggest that personal characteristics (personal and family background, self-perception, perceptions of women, sexual preferences etc), economic factors (education, income, work) as well as attitudes towards risk (both health hazard and risk of being caught where sex work is illegal), and attitude towards relationships and sex are all likely to affect demand. Previous theoretical work has argued that stigma plays a fundamental role in determining both demand and risk, and that in particular due to the presence of stigma the demand for sex and for paid sex are not, as has been argued elsewhere, perfect substitutes. We use data from the British Sexual Attitudes Survey of 2001 to test these hypotheses. We find a positive effect of education (proxy for income), negative effects of professional status (proxies for stigma associated with buying sex), positive and significant effects of all risky behavior variables and no significant effects of variables which measure the relative degree of conservatism in morals. We conclude with some policy implications.

Effect of enzymatic pretreatment and increasing the organic loading rate of lipid-rich wastewater treated in a hybrid UASB reactor

This study aimed at evaluating the effect of increasing organic loading rates and of enzyme pretreatment on the stability and efficiency of a hybrid upflow anaerobic sludge blanket reactor (UASBh) treating dairy effluent. The UASBh was submitted to the following average organic loading rates (OLR) 0.98 Kg.m(-3).d(-1), 4.58 Kg.m(-3).d(-1), 8.89 Kg.m(-3).d(-1) and 15.73 Kg.m(-3).d(-1), and with the higher value, the reactor was fed with effluent with and without an enzymatic pretreatment to hydrolyze fats. The hydraulic detention time was 24 h, and the temperature was 30 +/- 2 degrees C. The reactor was equipped with a superior foam bed and showed good efficiency and stability until an OLR of 8.89 Kg.m(-3).d(-1). The foam bed was efficient for solid retention and residual volatile acid concentration consumption. The enzymatic pretreatment did not contribute to the process stability, propitiating loss in both biomass and system efficiency. Specific methanogenic activity tests indicated the presence of inhibition after the sludge had been submitted to the pretreated effluent It was concluded that continuous exposure to the hydrolysis products or to the enzyme caused a dramatic drop in the efficiency and stability of the process, and the single exposure of the biomass to this condition did not inhibit methane formation. (C) 2011 Elsevier B.V. All rights reserved.

Effect of agitation on the performance of an anaerobic sequencing batch biofilm reactor in the treatment of dairy effluents

Agitation rate is an important parameter in the operation of Anaerobic Sequencing Biofilm Batch Reactors (ASBBRs), and a proper agitation rate guarantees good mixing, improves mass transfer, and enhances the solubility of the particulate organic matter. Dairy effluents have a high amount of particulate organic matter, and their anaerobic digestion presents inhibitory intermediates (e. g., long-chain fatty acids). The importance of studying agitation in such batch systems is clear. The present study aimed to evaluate how agitation frequency influences the anaerobic treatment of dairy effluents. The ASBBR was fed with wastewater from milk pasteurisation process and cheese manufacture with no whey segregation. The organic matter concentration, measured as chemical oxygen demand (COD), was maintained at approximately 8,000 mg/L. The reactor was operated with four agitation frequencies: 500 rpm, 350 rpm, 200 rpm, and no agitation. In terms of COD removal efficiency, similar results were observed for 500 rpm and 350 rpm (around 90%) and for 200 rpm and no agitation (around 80%). Increasing the system`s agitation thus not only improved the global efficiency of organic matter removal but also influenced volatile acid production and consumption and clearly modified this balance in each experimental condition.

A comparison of two bench-scale anaerobic systems used for the treatment of dairy effluents

The objective of this work was to compare two anaerobic reactor conflgurations, a hybrid upflow anaerobic sludge blanket (UASBh) reactor and an anaerobic sequencing batch reactor with immobilised biomass (ASBBR) treating dairy effluents. The reactors were fed with effluent from the milk pasteurisation process (effluent 1-E1) and later with effluent from the same process combined with the one from the cheese manufacturing (effluent 2-E2). The ASBBR reactor showed average organic matter removal efficiency of 95.2% for E1 and 93.5% for E2, while the hybrid UASB reactor showed removal efficiencies of 90.3% and 80.1% respectively.

The seaweed flora of Admiralty Bay, King George Island, Antarctic

Admiralty Bay is located on the western side of King George Island. Although several research teams of different nationalities have carried out surveys in the region for decades, there are only two publications dealing with the seaweed flora of the bay. Here, we report on a taxonomic survey of the seaweeds we collected during the 25th Brazilian Antarctic Expedition (December 2006/November 2007). We discovered 42 species (21 Rhodophyta, 14 Phaeophyceae, and 7 Chlorophyta), corresponding to an increase of about 31% in the seaweed biodiversity hitherto known for the region. Considering that the Antarctic Peninsula, adjacent to King George Island seems to be one of the most rapidly warming spots on the planet, this kind of survey may provide a valuable tool for detecting eventual changes in seaweed biodiversity.

Out of Amazonia again and again: episodic crossing of the Andes promotes diversification in a lowland forest flycatcher

Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability of appropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the Late Pliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespread plant and animal species occurring in lowland forests on both sides of the Andes challenge the generality of this hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of the other four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequences unambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage with origins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal events post-date Andean uplift.

CPDs and 6-4PPs play different roles in UV-induced cell death in normal and NER-deficient human cells

Ultraviolet (UV) light generates two major DNA lesions: cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6-4)-pyrimidone photoproducts (6-4PPs), but the specific participation of these two lesions in the deleterious effects of UV is a longstanding question. In order to discriminate the precise role of unrepaired CPDs and 6-4PPs in UV-induced responses triggering cell death, human fibroblasts were transduced by recombinant adenoviruses carrying the CPD-photolyase or 6-4PP-photolyase cDNAs. Both photolyases were able to prevent UV-induced apoptosis in cells deficient for nucleotide excision repair (NER) to a similar extent, while in NER-proficient cells UV-induced apoptosis was prevented only by CPD-photolyase, with no effects observed when 6-4PPs were removed by the specific photolyase. These results strongly suggest that both CPDs and 6-4PPs contribute to UV-induced apoptosis in NER-deficient cells, while in NER-proficient cells, CPDs are the only lesions responsible for UV-killing, probably due to the rapid repair of 6-4PPs by NER. As a consequence, the difference in skin photosensitivity, including carcinogenesis, of most of the xeroderma pigmentosum patients and of normal people is probably not only a quantitative aspect, but depends on the type of DNA damage induced by sunlight and its rate of repair. (c) 2007 Elsevier B.V. All rights reserved.

It takes guts for tolerance: The phenomenon of oral tolerance and the regulation of autoimmune response

The intestinal tract is a peculiar environment due to its constant contact with the microbiota agents, food antigens and other molecules. Such exposure requires the establishment of important regulatory mechanisms in order to avoid inflammatory response and self aggression. In this context, the GALT plays a very relevant role due to the presence of several different cellular populations which are the main players in this phenomenon. Moreover, it was described a while ago that the oral ingestion of a given molecule is able to induce systemic tolerance to the same molecule when it is used as an immunogen by parenteral route, known as oral tolerance. This observation led researches to use these mechanisms to induce tolerance against cognate antigens of different autoimmune diseases. In this context, in this review we focused on several tolerance inducing mechanisms which are relevant not only for the maintenance of intestinal tract but also for the suppression of T effector cells, such as Th1, Th2 and the newly described Th17 cells. To name a few, CD103(+) dendritic cells, Tr1 cells derived IL-10 secretion, Foxp3 conversion and CD4(+)LAP(+) regulatory cells induction are among the recently described features of the tolerogenic environment of the intestinal tract. (C) 2009 Elsevier B.V. All rights reserved.

Sustained activation of p53 in confluent nucleotide excision repair-deficient cells resistant to ultraviolet-induced apoptosis

p53 activation is one of the main signals after DNA damage, controlling cell cycle arrest, DNA repair and apoptosis. We have previously shown that confluent nucleotide excision repair (NER)-deficient cells are more resistant to apoptosis induced by ultraviolet irradiation (UV). Here, we further investigated the effect of cell confluence on UV-induced apoptosis in normal and NER-deficient (XP-A and XP-C) cells, as well as the effects of treatments with the ATWATR inhibitor caffeine, and the patterns of p53 activation. Strong p53 activation was observed in either proliferating or confluent cells. Caffeine increased apoptosis levels and inhibited p53 activation in proliferating cells, suggesting a protective role for p53. However, in confluent NER-deficient cells no effect of caffeine was observed. Transcription recovery measurements showed decreased recovery in proliferating XPA-deficient cells, but no recovery was observed in confluent cells. The levels of the cyclin/Cdk inhibitor, p21(Waf1/Cip1), correlated well with p53 activation in proliferating cells. Surprisingly, confluent cells also showed similar activation of p21(Waf1/Cip1). These results indicate that reduced apoptosis in confluent cells is associated with the deficiency in DNA damage removal, since this effect is not clearly observed in NER-proficient cells. Moreover, the strong activation of p53 in confluent cells, which barely respond to apoptosis, suggests that this protein, under these conditions, is not linked to UV-induced cell death signaling. (c) 2008 Elsevier B.V. All rights reserved.