3,086 research outputs found

    struc2vec: Learning Node Representations from Structural Identity

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    Structural identity is a concept of symmetry in which network nodes are identified according to the network structure and their relationship to other nodes. Structural identity has been studied in theory and practice over the past decades, but only recently has it been addressed with representational learning techniques. This work presents struc2vec, a novel and flexible framework for learning latent representations for the structural identity of nodes. struc2vec uses a hierarchy to measure node similarity at different scales, and constructs a multilayer graph to encode structural similarities and generate structural context for nodes. Numerical experiments indicate that state-of-the-art techniques for learning node representations fail in capturing stronger notions of structural identity, while struc2vec exhibits much superior performance in this task, as it overcomes limitations of prior approaches. As a consequence, numerical experiments indicate that struc2vec improves performance on classification tasks that depend more on structural identity.Comment: 10 pages, KDD2017, Research Trac

    Remoción de quistes de giardia duodenalis por filtración rápida

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    Con el objetivo de evaluar la remoción de quistes de Giardia duodenalis en agua, se construyó un filtro rápido por gravedad, a escala laboratorio, con arena (Tamaño efectivo: 0,95±0,03 mm) como material filtrante. El agua para la prueba de remoción (160 L) se preparó diluyendo una suspensión de quistes con H2Od hasta una turbiedad de 4 UNT. Para recuperar los quistes no removidos, el agua filtrada se pasó a través de membranas de nitrato de celulosa de 0,45 μm. El conteo de quistes se realizó en cámara de Neubauer. Mediante pruebas hidráulicas se estableció el espesor del lecho (0,75 m) y el tiempo de retención (5 min). La concentración de parásitos en el agua de entrada fue de 2,2 104 quistes/L, obteniéndose una remoción de 1,5 log (96,9 %). La turbiedad durante el periodo de filtración fue ≤ 1,22 UNT. Este trabajo confirma que aún en condiciones de filtración apropiadas, los quistes de Giardia pueden aparecer en el agua tratada cuando ocurre una elevada contaminación de la fuente.In order to evaluate the removal of cysts of Giardia duodenalis in water, a rapid gravity filter was constructed on laboratory scale with sand (effective size: 0.95 ± 0.03 mm) as a filter material. Water for the test (160 L) was prepared by diluting a suspension of cysts with H2Od until a turbidity of 4 UNT. To recover the unremoved cysts, the filtered water was passed through 0.45 μm cellulose nitrate membranes. The cysts count was performed in Neubauer chamber. The filter bed thickness (0.75 m) and the retention time (5 min) were established by hydraulic tests. The concentration of parasites in the incoming water was 2.2 104 cysts / L obtaining a removal of 1.5 log (96.9 %). The turbidity during the filtration period was ≤ 1.22 UNT. This investigation confirms that even under appropriate filtration conditions, cysts of Giardia can appear in the treated water when high source contamination occurs.Fil: Pizarro, A.. Universidad Nacional del LitoralFil: Zerbatto, M.. Universidad Nacional del LitoralFil: Pizarro, M.. Universidad Nacional del LitoralFil: Modini, L.. Universidad Nacional del Litora

    The Debt I Owe: Consequences of Criminal-Legal Debt in Metro Atlanta

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    Neoliberalism alters U.S. carceral practices to extract revenue from marginalized communities. The criminal-legal system made monetary sanctions (e.g., cash bail, traffic fines, probation fees) a common practice that affects the millions of people who cycle through the system. I argue that criminal-legal debt extends punishment outside of carceral structures and creates a “revolving door” effect in which poor, racialized communities are subjected to constant incarceration. Domestic violence cases in Atlanta are a prime example of this phenomenon and illustrates the ways in which incarceration aids neoliberalism. The over policing of minority communities, and by extension the imposition of monetary sanctions, in metro-Atlanta serves to generate revenue and gentrify those neighborhoods. Through a prison abolitionist lens, this research explores the impact of criminal-legal debt in metro-Atlanta through autoethnography, interviews, and online participant observation of court

    Novel Grasses and Legumes Germplam: Advances and Perspectives for Tropical Zones

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    It has been the aim, in the present article, to bring together as much as possible scientific evidence and experience in new available germplasm for tropical zones. The economic importance of the Brachiaria, Paspalum and Pennisetum grasses is well established. New germplasm has become available since 1980. This paper reviews evaluations of Brachiaria accessions in humid lowlands and savannas of tropical America. The selection criteria need to be revised. Also, it is necessary to expose the new material as early as possible to farmers in order to select new germplasm with high chances of adoption. Within the genus Paspalum, P. dilatatum is possibly the most widespread. It has made a considerable contribution in the past, providing some of the best early season feed. In this paper, new data on P. atratum will be presented. Since 1985 a great effort had been made on Pennisetum. New cultivars are available. The main legumes genera to be discussed are Arachis spp., Calopogonium mucunoides, Centrosema spp., Desmodium spp., Glycine spp., Macroptilium spp., Neonotonia wightii and Stylosanthes spp. On Arachis, a historical perspective of the collection and evaluation in South America as well as a summary of the regional experience on Central America, Australia and United States would be presented. Some preliminary data on the drought tolerance and animal performance is discussed. For more than one hundred accessions evaluated through 1992 until 1997, twenty accessions of A. pintoi are outstanding and deserve further regional evaluation. Calopogonium mucunoides, although not widely used (like any other pasture legume today in tropical America), is the most popular forage legume amongst farmers in Brazil. A collection of 215 accessions was evaluated in the Cerrado ecosystem. A negative relationship between the degree of pilosity and in vitro dry matter digestibility was found. Within the seventeen accessions selected, two of them, CIAT 822 and 20709 were outstanding for their leaf retention during the dry season. Also, Macroptilium, Neonotonia and Stylosanthes, deserve special mention because attempts to develop cultivars from them have been determined and sustained. Finally, there is also an opportunity to search for new alternatives within the new available collection of N. wightii. Three new accessions are promising

    Inclusion of [H3PW12O40] and [H4SiW12O40] into a silica gel matrix via "sol-gel" methodology

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    Indexación: Web of Science; Scopus.Here we report the inclusion of two Keggin Polyoxometalates (POMs), [H3PW12O40] and [H4SiW12O40], into silica gels by integrating them during the preparation of the SiO2 matrix via "sol-gel" methods. Aerogels were produced by supercritical drying of the wet gels impregnated with the POMs, and lyogels were obtained by means of a lyophilization process. These materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FT-IR) spectroscopy and thermoanalytical techniques (TGA-DSC). We found that a large fraction of POMs are lost during the aging time, and solvent exchange for lyophilization. However the thermal stability of the bare matrix is modified by the inclusion of POMs. Some aggregates with a high content of POMs were found via SEM-EDX.http://ref.scielo.org/3fg9t

    Closing the gap between business undergraduate education and the organisational environment: A Chilean case study applying experiential learning theory

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    In response to the continuous changes in Latin American higher education and the increasing demands for better prepared professionals, the Learning Connected to the Organisational Environment method was introduced in the course of Marketing at one public University in Chile. This was aimed as an integrated approach to education, providing pedagogical and social value by connecting organisations and real challenges with the learning objectives. This paper describes its design, implementation and initial impact on students’ learning process. Results on the impact of the LCOE method show that students valued learning with this new initiative (n = 158) and showed higher performance and improved quality of their written reports, along with higher evaluations of the teaching staff compared to students in the same course learning with traditional methods (n = 158). Discussion is centred on the value of this initiative and on suggestions for transference and future research

    Optimization of radiotherapy fractionation schedules based on radiobiological functions

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    Objective: To present a method for optimizing radiotherapy fractionation schedules using radiobiological tools and taking into account the patients dose-volume histograms (DVH). Methods: This method uses a figure of merit based on the uncomplicated tumour control probability (P+) and the generalized equivalent uniform dose (gEUD). A set of doses per fraction is selected in order to find the dose per fraction and the total dose, thus maximizing the figure of merit and leading to a biologically effective dose that is similar to the prescribed schedule. Results: As a clinical example, a fractionation schedule for a prostate treatment plan is optimized and presented herein. From a prescription schedule of 70 Gy/35 × 2 Gy, the resulting optimal schema, using a figure of merit which only takes into account P+, is 54.4 Gy/16 × 3.4 Gy. If the gEUD is included in that figure of merit, the result is 65 Gy/26 × 2.5 Gy. Alternative schedules, which include tumour control probability (TCP) and the normal tissue complication probability (NTCP) values are likewise shown. This allows us to compare different schedules instead of solely finding the optimal value, as other possible clinical factors must be taken into account to make the best decision for treatment. Conclusion: The treatment schedule can be optimized for each patient through radiobiological analysis. The optimization process shown below offers physicians alternative schedules that meet the objectives of the prescribed radiotherapy. Advances in knowledge: This article provides a simple, radiobiological-function-based method to take advantage of a patient''s dose-volume histograms in order to better select the most suitable treatment schedule

    Varieties of social cognition

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    Recent actions. KEYWORDS: implicit social work Influence within cognition, unconsciousness psychology demonstrates is cognition, corroborated that implicit unconscious by strong measures, empirical cognition priming, evidence, plays automaticity, a but central unconscious consciousness role in the states judgments are difficult and actions to verify. of We individuals. discuss procedures We distinguish aimed between at providing two basic conclusive types evidence unconscious of state social unconsciousness, cognition: unconsciousness and apply them of the to influences recent empirical on judgments findings. and actions, and unconscious of the mental states (i.e., attitudes and feelings) that give rise to judgments After reading words related to stereotypes of the elderly, such as “Florida ” and “wrinkle, ” people tend to walk more slowly (Bargh, Chen, & Burrows, 1996). Being subliminally exposed to pictures of African American males makes people hostile, and thinking about professors improves their performance at Trivial Pursuit (Bargh et al., 1996; Dijksterhuis & van Knippenberg, 1998). People are more likely to mistakenly judge a male to be famous, and an African American to be a criminal (Banaji & Bhaskar, 2000; Banaji & Greenwald, 1995; Payne, 2001). Based on these and other similarly dramatic findings, we and many other psychologists have come to agree with Bargh and Chartrand (1999), who proposed that: “... most of a person’s everyday life is determined not by their conscious intentions and deliberate choices but by mental processes that are put into motion by features of the environment and that operate outside of conscious awarenes

    Renewable energy regulation and structural breaks: An empirical analysis of Spanish electricity price volatility

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    International experience proves that electricity prices have undergone major changes in volatility since the entry of green technologies. The intermittency of renewable sources is one of the reasons for these changes, as it leads to higher volatility in periods of higher participation by renewables. We argue that the development of the regulatory system promoting renewable electricity also plays a crucial role. We raise a question that deserves attention: could an incentive scheme induce higher share of renewables and lower volatility simultaneously? In this paper, we conduct an empirical analysis with Spanish data. We analyze possible ensuing structural changes in Spanish electricity spot price volatility from January 2002 to December 2017. We identify two structural breaks linked to important measures related to renewable electricity: (i) the abolishment of the feed-in tariff scheme; and (ii) the establishment of a more market-oriented regulation based on investment and operating costs. We conclude that stable regulatory policies reduce volatility even though the presence of renewable sources is greater. Furthermore, market-based policy measures achieve lower volatility, encouraging good integration of intermittent renewable electricity. © 2020 Elsevier B.V.Financial support from Ministerio de Economa y Competitividad and Fondo Europeo de Desarrollo Regional under research grant ECO2015-64467-R (MINECO/FEDER) and from Dpto. de Educación, Universidades e Investigación del Gobierno Vasco under research grant IT1336-19 is acknowledged. Cristina Pizarro-Irizar also acknowledges financial support from Ministerio de Economa y Competitividad under research grant ECO2015-68023 , Ministerio de Ciencia, Innovación y Universidades under research grant RTI2018-093352-B-I00 , Gobierno Vasco through the BERC 2018-2021 program and by Ministerio de Economa y Competitividad MINECO through BC3 Maria de Maeztu excellence accreditation MDM-2017-0714 . All the authors are grateful for the valuable comments made by participants in the 41st International Conference of the International Association for Energy Economics and the 14th Conference of the Spanish Association for Energy Economics
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