Unveiling the complexity of human mobility by querying and mining massive trajectory data

The technologies of mobile communications pervade our society and wireless networks sense the movement of people, generating large volumes of mobility data, such as mobile phone call records and Global Positioning System (GPS) tracks. In this work, we illustrate the striking analytical power of massive collections of trajectory data in unveiling the complexity of human mobility. We present the results of a large-scale experiment, based on the detailed trajectories of tens of thousands private cars with on-board GPS receivers, tracked during weeks of ordinary mobile activity. We illustrate the knowledge discovery process that, based on these data, addresses some fundamental questions of mobility analysts: what are the frequent patterns of people’s travels? How big attractors and extraordinary events influence mobility? How to predict areas of dense traffic in the near future? How to characterize traffic jams and congestions? We also describe M-Atlas, the querying and mining language and system that makes this analytical process possible, providing the mechanisms to master the complexity of transforming raw GPS tracks into mobility knowledge. M-Atlas is centered onto the concept of a trajectory, and the mobility knowledge discovery process can be specified by M-Atlas queries that realize data transformations, data-driven estimation of the parameters of the mining methods, the quality assessment of the obtained results, the quantitative and visual exploration of the discovered behavioral patterns and models, the composition of mined patterns, models and data with further analyses and mining, and the incremental mining strategies to address scalability.     

Improvement in environmental accessibility via volunteered geographic information: a case study

Universal Access in the Information Society - Although geo-crowdsourcing approaches provide an opportunity to collect and share environmental accessibility information for people with disabilities,...     

Dynamics of Fatty Acids,Tocopherols and Phenolic Compounds Biogenesis During Olive (Olea europaea L.) Fruit Ontogeny

Fatty acids, tocopherols, and phenolic compounds biogenesis from two major Spanish olive cultivars (Arbequina and Manzanilla) were analyzed for the function of the thermal regime during the fruit ontogeny in a non‐Mediterranean environment. Bilinear models characterized the dynamics of fatty acid biogenesis. Regressions between the accumulated thermal time (TT) and the levels of both oleic and linoleic acids showed different responses to temperature of each olive cultivar. After reaching similar absolute maximum oleic acid contents at similar TT, the levels of this fatty acid decreased markedly in cv. Arbequina and its final concentration was 10 % lower than that found in cv. Manzanilla. In both cultivars, concentrations of all tocopherol isoforms were negatively associated with the TT accumulated over the entire oil accumulation period. Dynamics of phenolic compounds biogenesis showed no clear tendencies with TT. Nevertheless, and whatever the stage of fruit development, secoiridoids were the major phenolic components. Results suggest greater sensitivity of fatty acid metabolism to temperature in cv. Arbequina. This fact points out the necessity of appropriate evaluation of the ambient thermal characteristics before introducing this cultivar into new growing environments.     

Effect of Yacon (Smallanthus sonchifolius) fructooligosaccharide purification technique using activated charcoal or ion exchange fixed bed column on recovery,purity and sugar content

A rich in FOS and simple sugar yacon extract was clarified and decoloured and subsequently purified in an activated charcoal column at 25 and 40 °C using two or three stepwise elution with yields of 72.0–86.7% and 90–92.4% purity. Best results were obtained at 25 °C and two stepwise elution, with yield and purity of 81.5% and 92% but 9% sucrose and no glucose and fructose. Different cationic exchange resins on a clarified and demineralised extract at 25 and 60 °C had yields and purity of 73.1–99.4% and 75.0–88.2%, respectively. Best results were obtained with Diaion UBK530Na at 60 °C (99.4% yield and 88.2% purity) but 1.6, 2.7 and 7.5% of fructose, glucose and sucrose. The by‐product was rich in sugars (59–60.1% fructose, 28.3–32.8% glucose, 7.2–8.4% sucrose) and could be used by the feed and food industry.     

Automated Design of a Computer Vision System for Visual Food Quality Evaluation

Considerable research efforts in computer vision applied to food quality evaluation have been developed in the last years; however, they have been concentrated on using or developing tailored methods based on visual features that are able to solve a specific task. Nevertheless, today’s computer capabilities are giving us new ways to solve complex computer vision problems. In particular, a new paradigm on machine learning techniques has emerged posing the task of recognizing visual patterns as a search problem based on training data and a hypothesis space composed by visual features and suitable classifiers. Furthermore, now we are able to extract, process, and test in the same time more image features and classifiers than before. Thus, we propose a general framework that designs a computer vision system automatically, i.e., it finds—without human interaction—the features and the classifiers for a given application avoiding the classical trial and error framework commonly used by human designers. The key idea of the proposed framework is to select—automatically—from a large set of features and a bank of classifiers those features and classifiers that achieve the highest performance. We tested our framework on eight different food quality evaluation problems yielding a classification performance of 95 % or more in every case. The proposed framework was implemented as a Matlab Toolbox available for noncommercial purposes.     

Enzymatic browning in sliced and puréed avocado: A fractal kinetic study

Modelling of browning is essential to evaluate the effectiveness of the processes applied to obtain fresh-appearance foods and also to determine their shelf life. Computer vision and the fractal kinetic method were used to quantify browning in three avocado cultivars. Samples (avocado slices and purée) were stored at 4 °C and surface images were captured in the tiff format. Browning kinetic was derived from images using the L^∗ mean method and the fractal method. In another experiment, inhibitor kinetic was also quantified, using the polyphenol oxidase activity method (in purée samples) with 0.1%, 0.5% and 1% of sodium bisulfite. In the results for avocado slices, kinetic rate derived by the fractal kinetic method was higher than that obtained with the L^∗ mean method, but the opposite was observed when the avocado was pulping (avocado purée). Kinetic quantified by the fractal method was similarly inhibited by bisulfite, when compared with the L^∗ mean value or PPO activity value methods. In general, the fractal method can be used to record browning kinetic and to discriminate between avocado cultivars, initial structural state of the sample (slice or purée), or in experiments using browning inhibitors.     

Carbohydrate‐based polyurethanes: A comparative study of polymers made from isosorbide and 1,4‐butanediol

A set of linear polyurethanes containing isosorbide units were synthesized by polymerization in solution from HDI and MDI diisocyanates and 1,4‐butanediol (BD), isosorbide (Is) or diisosorbide diurethanes (Is₂HDI and Is₂MDI) as diols. The thermal transitions, thermal stability, and crystal structure of the polyurethane homopolymers and copolymers containing isosorbide were evaluated and compared with those displayed by their polyurethane analogues entirely made of BD. It was found that incorporation of Is units in the polyurethane chain produced significant changes in T_g, T_m, and T_d but no significant differences were noticed between copolymers made from Is or Is₂ monomers. Degradation assays revealed that the presence of Is units increased slightly the hydrolysis rate of polyurethanes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Soaking in a NaCl solution produce paler potato chips

Pairs of potato slices were blanched, soaked in a NaCl solution or water and fried. The originally adjoining faces of the chips were analysed for average L^*a^*b^* color by digital photography and image analysis.Stepwise increases in blanching temperature (60, 65, 70, 75, 80 °C/5 min) gave rise to gradually darker chips above 65 °C, by a total of 9L^* units (P=0.001). Slices soaked after blanching in a 3% NaCl solution for 5 min were consistently paler by 5L^* units (P=0.0054) than those soaked in water only.Change in the concentration range 0.6-9% NaCl was found using one-tailed paired t-test, subsequent to blanching at 70 °C/5 min (P=0.0125).     

Diamondoid Amino Acid-Based Peptide Kinase A Inhibitor Analogues

The incorporation of diamondoid amino acids (DAAs) into peptide-like drugs is a general strategy to improve lipophilicity, membrane permeability, and metabolic stability of peptidomimetic pharmaceuticals. We designed and synthesized five novel peptidic DAA-containing kinase inhibitors of protein kinase A using a sophisticated molecular dynamics protocol and solid-phase peptide synthesis. By means of a thermophoresis binding assay, NMR, and crystal structure analysis, we determined the influence of the DAAs on the secondary structure and binding affinity in comparison to the native protein kinase inhibitor, which is purely composed of proteinogenic amino acids. Affinity and binding pose are largely conserved. One variant showed 6.5-fold potency improvement, most likely related to its increased side chain lipophilicity. A second variant exhibited slightly decreased affinity presumably due to loss of hydrogen-bond contacts to surrounding water molecules of the first solvation shell.     

Photoperiod-Dependent Effects of Grape-Seed Proanthocyanidins on Adipose Tissue Metabolic Markers in Healthy Rats

Scope

Variations in photoperiod patterns drive metabolic adaptations in mammals, involving important changes in body weight and adiposity. Moreover, (poly)phenols can help heterotrophs adopt metabolic adaptations to face the upcoming environmental conditions. Particularly, proanthocyanidins from grape-seeds show photoperiod-dependent effects on different metabolic parameters. The present study aims to explore whether grape-seed proanthocyanidin extract (GSPE) consumption differently affects the expression of metabolic markers in WAT (subcutaneous and visceral depots) and BAT in a photoperiod-dependent manner.

Methods and results

GSPE (25 mg kg⁻¹ day⁻¹) is orally administrated for 4 weeks to healthy rats exposed to three photoperiods (L6, L12, and L18). In WAT, GSPE consumption significantly upregulates the expression of lipolytic genes in all photoperiods, being accompanied by increased serum concentrations of glycerol and corticosterone only under the L6 photoperiod. Moreover, adiponectin mRNA levels are significantly upregulated in response to GSPE regardless of the photoperiod, whereas Tnfα and Il6 expression are only downregulated in L6 and L18 photoperiods but not in L12. In BAT, GSPE upregulates Pgc1α expression in all groups, whereas the expression of Pparα is only increased in L18.

Conclusions

The results indicate that GSPE modulates the expression of important metabolic markers of WAT and BAT in a photoperiod-dependent manner.