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Search Results: 1 - 10 of 3919 matches for " Ramon Aparicio-Pardo "
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Heuristic Approaches for Periodic Reconfiguration of Lightpath-based Networks under Multi-hour Traffic
Ramon Aparicio-Pardo,Belen Garcia-Manrubia,Nina Skorin-Kapov,Pablo Pavon-Marino
Journal of Networks , 2012, DOI: 10.4304/jnw.7.5.800-811
Abstract: Periodic lightpath reconfiguration of virtual topologies in transparent optical networks has been recently investigated as a mechanism to more efficiently adapt the network to predictable periodic traffic variations along a day or week. Scheduling periodic reconfigurations involves tuning a trade-off between a lower network cost obtained through better resource allocation, and undesired traffic disruptions that these reconfigurations may cause. This paper presents and compares two algorithms for planning a reconfigurable virtual topology suitable for exploring this trade-off. The first is based on a Lagrangean Relaxation of the planning problem, and the second is based on a Tabu Search meta-heuristic. The merits of both algorithms are assessed for moderate network sizes through comparison with analytical lower bounds and exact solutions obtained by a MILP formulation.
Optimized Adaptive Streaming Representations based on System Dynamics
Laura Toni,Ramon Aparicio-Pardo,Karine Pires,Gwendal Simon,Alberto Blanc,Pascal Frossard
Computer Science , 2014, DOI: 10.1145/2700294
Abstract: Adaptive streaming addresses the increasing and heterogenous demand of multimedia content over the Internet by offering several encoded versions for each video sequence. Each version (or representation) has a different resolution and bit rate, aimed at a specific set of users, like TV or mobile phone clients. While most existing works on adaptive streaming deal with effective playout-control strategies at the client side, we take in this paper a providers' perspective and propose solutions to improve user satisfaction by optimizing the encoding rates of the video sequences. We formulate an integer linear program that maximizes users' average satisfaction, taking into account the network dynamics, the video content information, and the user population characteristics. The solution of the optimization is a set of encoding parameters that permit to create different streams to robustly satisfy users' requests over time. We simulate multiple adaptive streaming sessions characterized by realistic network connections models, where the proposed solution outperforms commonly used vendor recommendations, in terms of user satisfaction but also in terms of fairness and outage probability. The simulation results further show that video content information as well as network constraints and users' statistics play a crucial role in selecting proper encoding parameters to provide fairness a mong users and to reduce network resource usage. We finally propose a few practical guidelines that can be used to choose the encoding parameters based on the user base characteristics, the network capacity and the type of video content.
Cold H2O and CO ice and gas toward the Galactic Center
Andrea Moneti,Jose Cernicharo,Juan Ramon Pardo
Physics , 2000, DOI: 10.1086/319168
Abstract: We present observations of CO, 13CO and of H2O in the middle and far-infrared taken with the ISO-SWS and ISO-LWS spectrometers toward two positions in the Galactic Center region (Sgr A* and GCS-3). Both ice and gas phase molecules are detected. The ISO data have been complemented with observations of the J=3-2 and J=7-6 lines of CO carried out at the Caltech Submillimeter Observatory. The ISO and CSO data indicate that the absorbing gas is extremely cold, T_K ~ 10 K, suggesting that it is located in the dark clouds of the different spiral arms that intersect the line of sight towards the Galactic Center. From the analysis of the CO absorption we derive 13CO gas phase column densities of 1.1 and 0.7E17 cm-2 towards Sgr A* and GCS-3, respectively. The H2O gas column density in the direction of Sgr A* is ~ 2E16 cm-2. The derived CO/H2O and gas/solid abundance ratios corresponding to these cold clouds are remarkably similar along the two lines of sight. We find that nearly all the CO is in the gas phase, while the H2O is almost entirely frozen onto the surfaces of cold dust grains. Finally, the N_{gas+ice}(CO)/N_{gas+ice}(H2O) abundance ratio is ~5 implying that H2O formation processes are highly efficient.
Waning Sovereignty? The Kindred Myths of “Origins” and “Vanishing” of the State  [PDF]
Ramon Maiz
Open Journal of Political Science (OJPS) , 2017, DOI: 10.4236/ojps.2017.73032
Abstract: This article discusses, from an historical-neo-institutionalist and relational-strate- gic perspective, the postmodern thesis of the end of the state due to the increasing processes of world globalization. The main hypothesis is that the arguments which predict the structural crisis or the disappearance of the State in the age of neo-liberal globalization have their roots in a theoretically and historically implausible concept of sovereignty that ignores and distorts central aspects of statehood and state-building in terms of both institutional structure and political action. The myth of the “origins” of the State in Medieval or Renaissance times shares with the postmodern vision of the “vanishing” of the state, the same underlying misconception of the scope and limits of the state power. Sovereignty (the monopolization of political power) was always a claim, a desiderata, a contested andunfinished political project not an accomplished empirical fact.
Chemoprophylaxis in Contacts of Patients with Cholera: Systematic Review and Meta-Analysis
Ludovic Reveiz, Evelina Chapman, Pilar Ramon-Pardo, Tracey Perez Koehlmoos, Luis Gabriel Cuervo, Sylvain Aldighieri, Amy Chambliss
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027060
Abstract: Introduction There is a pressing need for effective measures to prevent the spread of cholera. Our systematic review assesses the effects of chemoprophylaxis in preventing cholera among exposed contacts. Methods and Findings We considered published and unpublished reports of studies up to July 2011. For this we searched: PubMed (1966 to July, 2011), Embase (1980 to July 2011), Cochrane Central Register of Controlled Trials (6; 2011), LILACS (1982 to July, 2011), the International Clinical Trials Registry Platform (July 2011) and references of identified publications. We included controlled clinical trials (randomized and non-randomized) in which chemoprophylaxis was used to prevent cholera among patient contacts. The main outcome measures were hospitalization and laboratory diagnosis of cholera in contacts for cholera patients. We assessed the risk of bias. We identified 2638 references and these included 2 randomized trials and 5 controlled trials that added up to a total of 4,154 participants. The risk of bias scored high for most trials. The combined results from two trials found that chemoprophylaxis reduced hospitalization of contacts during the follow-up period by 8–12 days (2826 participants; RR 0.54 95% CI 0.40–0.74;I2 0%). A meta-analysis of five trials found a significant reduction in disease among contacts with at least one positive sample who received chemoprophylaxis during the overall follow-up (range 4–15 days) (1,414 participants; RR 0.35 95% CI 0.18–0.66;I2 74%). A significant reduction in the number of positive samples was also found with chemoprophylaxis (3 CCT; 6,918 samples; RR 0.39 95% CI 0.29–0.51;I2 0%). Conclusion Our findings suggest that chemoprophylaxis has a protective effect among household contacts of people with cholera but the results are based on studies with a high risk of bias. Hence, there is a need for adequate reliable research that allows balancing benefits and harms by evaluating the effects of chemoprophylaxis.
Utility of the Mini-Cog for Detection of Cognitive Impairment in Primary Care: Data from Two Spanish Studies
Cristóbal Carnero-Pardo,Isabel Cruz-Ordu?a,Beatriz Espejo-Martínez,Carolina Martos-Aparicio,Samuel López-Alcalde,Javier Olazarán
International Journal of Alzheimer's Disease , 2013, DOI: 10.1155/2013/285462
Abstract: Objectives. To study the utility of the Mini-Cog test for detection of patients with cognitive impairment (CI) in primary care (PC). Methods. We pooled data from two phase III studies conducted in Spain. Patients with complaints or suspicion of CI were consecutively recruited by PC physicians. The cognitive diagnosis was performed by an expert neurologist, after formal neuropsychological evaluation. The Mini-Cog score was calculated post hoc, and its diagnostic utility was evaluated and compared with the utility of the Mini-Mental State (MMS), the Clock Drawing Test (CDT), and the sum of the MMS and the CDT ( ) using the area under the receiver operating characteristic curve (AUC). The best cut points were obtained on the basis of diagnostic accuracy (DA) and kappa index. Results. A total sample of 307 subjects (176 CI) was analyzed. The Mini-Cog displayed an AUC (±SE) of , which was significantly inferior to the AUC of the CDT ( ), the MMS ( ), and the ( ). The best cut point of the Mini-Cog was 1/2 (sensitivity 0.60, specificity 0.90, DA 0.73, and kappa index ). Conclusions. The utility of the Mini-Cog for detection of CI in PC was very modest, clearly inferior to the MMS or the CDT. These results do not permit recommendation of the Mini-Cog in PC. 1. Introduction The aging of the population has come along with an increase in the incidence of cognitive impairment (CI) [1], a clinical syndrome that, in about one-third of the patients, precedes dementia [2]. An early detection of CI could produce benefits at different levels, including early dementia diagnosis, access to treatments, and delay or even reversion of cognitive deterioration [3–5]. Primary care (PC) presents optimal characteristics of accessibility and continuity of care, which are essential for early detection and management of CI [6]. In this vein, the focus of the PC physicians should be the detection of CI, rather than dementia. A separation of mild cognitive impairment (MCI) and dementia would not only be difficult or arbitrary in many instances but would also lead to missing opportunities for treatment and research [7]. The detection of CI requires a proactive attitude and the use of cognitive tests. In PC, cognitive tests need to be brief and easy to administer and interpret. In addition, these tests should have been specifically validated in the PC setting, with an adequate control of the potential influence of age, education, and other social variables [8]. Albeit not simple, rather long, and very influenced by education, the Mini-Mental State (MMS) [9] is still the most used
A Systematic Computational Study on Flavonoids
Santiago Aparicio
International Journal of Molecular Sciences , 2010, DOI: 10.3390/ijms11052017
Abstract: 17 selected flavones derivatives, flavonoids, were analyzed through a systematic B3LYP∕6-311++G** computational study with the aim of understanding the molecular factors that determine their structural and energetic properties in gas phase. Flavonoids were selected in a systematic way to infer the effect of the number and relative positions of hydroxyl groups on molecular properties. Different conformers for each flavonoid were analyzed and the strength and topology of the intramolecular hydrogen bonds studied through the computation of the corresponding torsional profiles. Atoms in a Molecule, and Natural Bond Orbital methodology was applied to the analysis of charge distribution along the studied molecules, and the intramolecular hydrogen bonds. Molecular shapes were studied through full geometry optimization, and the position of the catechol ring analyzed through dihedral scans.
Cultura institucional y homogeneizacion mental: un analisis de impacto en universitarios
Aparicio,Miriam;
Interdisciplinaria , 2005,
Abstract: this study tests hypotheses included in the psycho-sociocommunicational paradigm, which emphasizes the long term cognitive effects of the media and the role of the psychosocial subject as recipient: the hypothesis of agenda-setting. the primary objectives were: (1) to elucidate such effects in audiences with different levels of education, (2) to detect levels of manipulation and homogenization of the mental maps linked with the centralization of the fourth power, to ascertain personality factors which condition differential receptivity of the addresses (filter of the news) related to the socio-evaluative context. two lines interest us: the first emphasizes the effects of the media according to individual psychology, and the second, centered on different parameters linked with psychosocial characteristics of the youths and the messages. finally, the central hypotheses are offered, taking into account that forty nine were considered: (a) there would be a marked correlation between the order of importance assigned to the information by the media and the one adopted by youths (high incidence of mental construing), (b) receptivity of the addresses would vary according to cognitive competence and (c) certain psychological characteristics would render the subject less impressionable to media influence. the sample was made up of graduates (n = 516) and drop-outs from eighteen careers in universidad nacional de cuyo (argentina) between 1980-1993. the sampling was stratified and of random start, confidence interval was taken at 95% and error margin at 4%. quanti-qualitative techniques were complemented: semistructured survey, indepth interviews, life stories and anecdote accounts. also, tests were applied in order to observe the behavior of certain psychosocial variables (such as locus of control, stress, aggressiveness, self-esteem). some of these tests (e.g. cep, j.l. pinillos, maudsley's inventory, j. eysenck) have been validated in argentina by the author. the analysis wa
Análisis estadístico de la elección presidencial de 2006: ?Fraude o errores aleatorios?
Aparicio, Javier;
Política y gobierno , 2009,
Abstract: this paper tests some of the main fraud allegations of the 2006 presidential election in mexico with the evidence from a statistical analysis of precinct-level data. first, i analyze the data flow from the quick count, the preliminary results (prep) and the official district tally (cómputo distrital). secondly, i analyze the size and distribution of errors in the polling-station acts and the partial recount. lastly, i consider atypical precincts and the role of party representatives. my main conclusion is that, since most fraud allegations are not supported by the evidence, the presidential election outcome is statistically reliable.
Libros
Aparicio, R.
Grasas y Aceites , 2010,
Abstract:
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