143 research outputs found

    Corridor Detection from Large GPS Trajectories Datasets

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    Given the widespread use of mobile devices that track their geographical location, it has become increasingly easy to acquire information related to users' trips in real time. This availability has triggered several studies based on user's position, such as the analysis of flows of people in cities, and also new applications, such as route recommendation systems. Given a dataset of geographical trajectories in an urbanmetropolitan area,we propose a algorithmto detect corridors. Corridors can be defined as geographical paths, with a minimum length, that are commonly traversed by a minimum number of different users. We propose an efficient strategy based on the Apriori algorithm to extract frequent trajectory patterns from the geo-spatial dataset. By discretizing the data and adapting the roles of itemsets and baskets of this algorithm to our context, we find the longest corridors formed by cells shared by a minimum number of trajectories. After that, we refine the results obtained with a subsequent filtering step, by using a Radius Neighbors Graph. To illustrate the algorithm, the GeoLife dataset is analyzed by following the proposed method. Our approach is relevant for transportation analytics because it is the base to detect lacking lines in public transportation systems and also to recommend to private users which route to take when moving from one part of the city to another on the basis of behavior of the users who provided their logs

    FindGeo: a tool for determining metal coordination geometry.

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    Abstract Summary: Metals are essential for the structure and function of many proteins and nucleic acids. The geometrical arrangement of the atoms that coordinate a metal in a biological macromolecule is an important determinant of the specificity and role of that metal. At present, however, this information can be retrieved only from the literature, which sometimes contains an improper or incorrect description of the geometry, and often lacks it altogether. Thus, we developed FindGeo to quickly and easily determine the coordination geometry of selected, or all, metals in a given structure. FindGeo works by superimposing the metal-coordinating atoms in the input structure to a library of templates with alternative ideal geometries, which are ranked by RMSD to identify the best geometry assignment. Availability: FindGeo is freely available as a web service and as a stand-alone program at http://metalweb.cerm.unifi.it/tools/findgeo/. Contact: [email protected] Supplementary information: Supplementary data are available at Bioinformatics online

    MetalPDB: a database of metal sites in biological macromolecular structures

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    We present here MetalPDB (freely accessible a

    Measuring the impact of COVID-19 restrictions on mobility: A real case study from Italy

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    When COVID-19 first struck the provinces of Northern Italy in early 2020 (especially in Lombardy and in EmiliaRomagna), the conditions there made it a perfect storm. The virus outbreak spread with an unusual violence (in the period from late February to April 2020), with a catastrophic toll in terms of human deaths. Taken by surprise, Italy mandated a complete nation-wide lockdown, successively resorting to ministerial decrees alleviating and postponing the restrictions. Now more than ever, there is an increased awareness on ICT used to combat the pandemic. In this article, we present a quantitative analysis evidencing the impact of restrictions on mobility. To this end, we rely on a vehicular mobility dataset confined in the downtown area of Bologna, Italy. Pursuing the objective, we propose a modified version of a state-of-theart data mining algorithm, allowing us to efficiently identify and quantify mobility flows. The proposal, if combined with additional data sources, could allow for a fine-grained and timely decision making, combating the pandemic

    A massive nebula around the Luminous Blue Variable star RMC143 revealed by ALMA

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    The luminous blue variable (LBV) RMC143 is located in the outskirts of the 30~Doradus complex, a region rich with interstellar material and hot luminous stars. We report the 3σ3\sigma sub-millimetre detection of its circumstellar nebula with ALMA. The observed morphology in the sub-millimetre is different than previously observed with HST and ATCA in the optical and centimetre wavelength regimes. The spectral energy distribution (SED) of RMC143 suggests that two emission mechanisms contribute to the sub-mm emission: optically thin bremsstrahlung and dust. Both the extinction map and the SED are consistent with a dusty massive nebula with a dust mass of 0.055±0.018 M0.055\pm0.018~M_{\odot} (assuming κ850=1.7cm2g1\kappa_{850}=1.7\rm\,cm^{2}\,g^{-1}). To date, RMC143 has the most dusty LBV nebula observed in the Magellanic Clouds. We have also re-examined the LBV classification of RMC143 based on VLT/X-shooter spectra obtained in 2015/16 and a review of the publication record. The radiative transfer code CMFGEN is used to derive its fundamental stellar parameters. We find an effective temperature of 8500\sim 8500~K, luminosity of log(L/L)=5.32(L/L_{\odot}) = 5.32, and a relatively high mass-loss rate of 1.0×105 M1.0 \times 10^{-5}~M_{\odot}~yr1^{-1}. The luminosity is much lower than previously thought, which implies that the current stellar mass of 8 M\sim8~M_{\odot} is comparable to its nebular mass of 5.5 M\sim 5.5~M_{\odot} (from an assumed gas-to-dust ratio of 100), suggesting that the star has lost a large fraction of its initial mass in past LBV eruptions or binary interactions. While the star may have been hotter in the past, it is currently not hot enough to ionize its circumstellar nebula. We propose that the nebula is ionized externally by the hot stars in the 30~Doradus star-forming region.Comment: Paper accepted by A&A on 09/05/2019 and in proof stage. Second comments by referee are included in this versio

    Discovering anomalies in big data: a review focused on the application of metaheuristics and machine learning techniques

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    With the increase in available data from computer systems and their security threats, interest in anomaly detection has increased as well in recent years. The need to diagnose faults and cyberattacks has also focused scientific research on the automated classification of outliers in big data, as manual labeling is difficult in practice due to their huge volumes. The results obtained from data analysis can be used to generate alarms that anticipate anomalies and thus prevent system failures and attacks. Therefore, anomaly detection has the purpose of reducing maintenance costs as well as making decisions based on reports. During the last decade, the approaches proposed in the literature to classify unknown anomalies in log analysis, process analysis, and time series have been mainly based on machine learning and deep learning techniques. In this study, we provide an overview of current state-of-the-art methodologies, highlighting their advantages and disadvantages and the new challenges. In particular, we will see that there is no absolute best method, i.e., for any given dataset a different method may achieve the best result. Finally, we describe how the use of metaheuristics within machine learning algorithms makes it possible to have more robust and efficient tools

    Contribution of miR-145-5p/Ago2 complex to the regulation of epithelial-mesenchymal transition

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    The epithelial-mesenchymal transition (EMT) is essential for cell fate determination during development but it is involved in pathological processes like cancer as well, being one of the first steps in the mechanisms leading to metastasis. miR-145-5p is one of the most widely recognized tumor-suppressor miRNAs, able to regulate cell migration and EMT through the contribution of the RISC complex in which Argonaute (Ago) proteins are required for target recognition and gene silencing [1]. Ago2 is an important member of the Ago family and its overexpression correlates with a transformed phenotype in breast cancer cells [2]. With the aim to unravel miR-145-5p/Ago2 contribution to the suppression of cancer progression in epithelial tumors, here we show that: i) miR-145-5p and Ago2 are down-regulated in breast tumor vs normal tissues; ii) the restored expression of miR-145-5p in breast cancer cell lines results in the reduction of tumor phenotype; iii) Ago2 expression is positively and specifically regulated by miR-145-5p; iv) miR-145-5p-dependent Ago2 induction is necessary for the inhibition of cell migration; v) when Ago2 is depleted, the formation of an alternative miR-145-5p/Ago1 active complex redirects miR-145-5p tumor suppressor function and correlates with a more invasive phenotype in breast cancer cells. These results open to the identification of miR-145-5p/Ago2-dependent molecular networks involved in the maintenance and progression of cancer phenotype

    Caesarean section provision and readiness in Tanzania: analysis of cross-sectional surveys of women and health facilities over time.

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    OBJECTIVES: To describe trends in caesarean sections and facilities performing caesareans over time in Tanzania and examine the readiness of such facilities in terms of infrastructure, equipment and staffing. DESIGN: Nationally representative, repeated cross-sectional surveys of women and health facilities. SETTING: Tanzania. PARTICIPANTS: Women of reproductive age and health facility staff. MAIN OUTCOME MEASURES: Population-based caesarean rate, absolute annual number of caesareans, percentage of facilities reporting to perform caesareans and three readiness indicators for safe caesarean care: availability of consistent electricity, 24 hour schedule for caesarean and anaesthesia providers, and availability of all general anaesthesia equipment. RESULTS: The caesarean rate in Tanzania increased threefold from 2% in 1996 to 6% in 2015-16, while the total number of births increased by 60%. As a result, the absolute number of caesareans increased almost fivefold to 120 000 caesareans per year. The main mechanism sustaining the increase in caesareans was the doubling of median caesarean volume among public hospitals, from 17 caesareans per month in 2006 to 35 in 2014-15. The number of facilities performing caesareans increased only modestly over the same period. Less than half (43%) of caesareans in Tanzania in 2014-15 were performed in facilities meeting the three readiness indicators. Consistent electricity was widely available, and 24 hour schedules for caesarean and (less systematically) anaesthesia providers were observed in most facilities; however, the availability of all general anaesthesia equipment was the least commonly reported indicator, present in only 44% of all facilities (34% of public hospitals). CONCLUSIONS: Given the rising trend in numbers of caesareans, urgent improvements in the availability of general anaesthesia equipment and trained anaesthesia staff should be made to ensure the safety of caesareans. Initial efforts should focus on improving anaesthesia provision in public and faith-based organisation hospitals, which together perform more than 90% of all caesareans in Tanzania

    Earthquake Geotechnical Engineering Aspects of the 2012 Emilia-Romagna Earthquake (Italy)

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    On May 20, 2012 an earthquake of magnitude ML=5.9 struck the Emilia Romagna Region of Italy and a little portion of Lombardia Region. Successive earthquakes occurred on May 29, 2012 with ML=5.8 and ML=5.3. The earthquakes caused 27 deaths, of which 13 on industrial buildings. The damage was considerable. 12,000 buildings were severely damaged; big damages occurred also to monuments and cultural heritage of Italy, causing the collapse of 147 campaniles. The damage is estimated in about 5-6 billions of euro. To the damage caused to people and buildings, must be summed the indirect damage due to loss of industrial production and to the impossibility to operate for several months. The indirect damage could be bigger than the direct damage caused by the earthquake. The resilience of the damaged cities to the damage to the industrial buildings and the lifelines was good enough, because some industries built a smart campus to start again to operate in less of one month and structural and geotechnical guidelines were edited to start with the recovering the damage industrial buildings. In the paper a damage survey is presented and linked with the ground effects. Among these, soil amplification and liquefaction phenomena are analyzed, basing on the soil properties evaluation by field and laboratory tests. Particular emphasis is devoted to the damaged suffered by the industrial buildings and to the aspects of the remedial work linked with the shallow foundation inadequacy and to the liquefaction mitigation effects
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