National University of La Plata

About: National University of La Plata is a education organization based out in La Plata, Argentina. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 12993 authors who have published 30013 publications receiving 495118 citations. The organization is also known as: UNLP & Universidad Nacional de La Plata.

Optical microvariability of southern agns

Abstract: We present results of a search for optical mi- crovariability in a selected sample of 23 southern AGNs, which includes both radio-quiet and radio-loud objects. Microvariations were clearly detected in 60% of the radio- loud sources, with amplitudes from 2.2% up to 8% within a single night. Night-to-night variability with amplitudes of 20% was also observed in the BL Lac object 0537 441. On the contrary, no rapid variability was detected at all in 8 radio-quiet quasars. We have used microvariability data previously reported for northern objects along with our new results for southern AGNs in order to estimate duty cycles of each class of objects from the largest possible sample. Most of the microvariability in radio-loud objects could be originating in interactions between relativistic shocks and features in the inner jets, although contributions from superluminal microlensing and accretion disk instabilities can be present in some sources. It is possible that the lat- ter phenomenon is responsible for the microvariability ob- served in northern radio-quiet quasars. We suggest that the dierence in the microvariability behaviour of radio and X-ray selected BL Lacs could be due to the eect of stronger magnetic elds in the latter group of objects, elds that can prevent the formation of features like den- sity inhomogeneities and bends in the base of the jets by Kelvin-Helmholtz macroscopic instabilities.

Pertussis Across the Globe: Recent Epidemiologic Trends From 2000 to 2013.

Abstract: Pertussis has reemerged as a problem across the world. To better understand the nature of the resurgence, we reviewed recent epidemiologic data and we report disease trends from across the world. Published epidemiologic data from January 2000 to July 2013 were obtained via PubMed searches and open-access websites. Data on vaccine coverage and reported pertussis cases from 2000 through 2012 from the 6 World Health Organization regions were also reviewed. Findings are confounded not only by the lack of systematic and comparable observations in many areas of the world but also by the cyclic nature of pertussis with peaks occurring every 3-5 years. It appears that pertussis incidence has increased in school-age children in North America and western Europe, where acellular pertussis vaccines are used, but an increase has also occurred in some countries that use whole-cell vaccines. Worldwide, pertussis remains a serious health concern, especially for infants, who bear the greatest disease burden. Factors that may contribute to the resurgence include lack of booster immunizations, low vaccine coverage, improved diagnostic methods, and genetic changes in the organism. To better understand the epidemiology of pertussis and optimize disease control, it is important to improve surveillance worldwide, irrespective of pertussis vaccine types and schedules used in each country.

International Perspectives on the practical application of violence risk assessment : a global survey of 44 countries

Abstract: Mental health professionals are routinely called upon to assess the risk of violence presented by their patients. Prior surveys of risk assessment methods have been largely circumscribed to individual countries and have not compared the practices of different professional disciplines. Therefore, a Web-based survey was developed to examine methods of violence risk assessment across six continents, and to compare the perceived utility of these methods by psychologists, psychiatrists, and nurses. The survey was translated into nine languages and distributed to members of 59 national and international organizations. Surveys were completed by 2135 respondents from 44 countries. Respondents in all six continents reported using instruments to assess, manage, and monitor violence risk, with over half of risk assessments in the past 12 months conducted using such an instrument. Respondents in Asia and South America reported conducting fewer structured assessments, and psychologists reported using instruments more ...

Distinguishing chaotic and stochastic dynamics from time series by using a multiscale symbolic approach

Abstract: In this paper we introduce a multiscale symbolic information-theory approach for discriminating nonlinear deterministic and stochastic dynamics from time series associated with complex systems. More precisely, we show that the multiscale complexity-entropy causality plane is a useful representation space to identify the range of scales at which deterministic or noisy behaviors dominate the system's dynamics. Numerical simulations obtained from the well-known and widely used Mackey-Glass oscillator operating in a high-dimensional chaotic regime were used as test beds. The effect of an increased amount of observational white noise was carefully examined. The results obtained were contrasted with those derived from correlated stochastic processes and continuous stochastic limit cycles. Finally, several experimental and natural time series were analyzed in order to show the applicability of this scale-dependent symbolic approach in practical situations.