Estimation of social network user's influence in a given area of expertise

Nowadays social networks are frequently used to express personal opinion on a topic of interest. Some users' opinion has more informational influence than others do. These users are called influential users. There are services that allow evaluating how popular and influential users are; however, any information on evaluation methods is proprietary and represents know-how of such software services. Furthermore, most services could not provide extensive data on the influential users within the specified area of knowledge. This article proposes the method of evaluating a user influence index within a social network in a given area of expertise

Mitochondrial DNA genetic relationships at the ancient Neolithic site of Tell Halula

The extent of racemization of aspartic acid (Asp) -expressed as D/L ratio- has been used as a marker of biomolecular degradation in ancient remains. However, Asp racemization rate is highly variable, and depends on biochemical and geochemical factors. In this paper we aim to determine to which extent the fraction analyzed and the kind of sample used may influence the D/L Asp ratios. Other factors, such as burial site and sample preservation conditions, are also considered. D/L Asp ratios were obtained in 38 ancient human samples from 30 different individuals in which Real Time PCR quantification and amplification of short mtDNA fragments had been previously achieved. Four samples were taken from bones, 16 from whole teeth and 18 from dentine. In 7 cases whole tooth and dentine fractions from the same individual were analyzed. The samples belonged to 8 archaeological sites from Pre-pottery Neolithic B (PPNB), Cardial Neolithic and Chalcolithic time periods. Results show significant differences between the D/L Asp ratios obtained in dentine and whole tooth fractions from the same tooth and individual, as well as among dentine samples from the same archaeological site and among samples of the same age from different, though nearby, archaeological sites. Ancient DNA (aDNA) could be characterized in the majority of the samples, independently from their racemization values, which suggests that other factors, apart from the sample preservation stage, are more significantly affecting the racemization rate. A generalized use of the Asp racemization ratio as a threshold value for ancient DNA preservation needs to be questioned until further methodological standardization is considered

3D Printed hydroponic system

Hydroponic systems have been around for many years and there is a large variety of designs. This project approaches the design of a stackable hydroponic system for domestic use aiming for high yield. The 3-D printed prototype consisted of cylindrical elements each with three entries for seeding. These elements can be stacked up and rotated around one another providing configuration flexibility. In addition, the cap of our system is a half cylindrical element. A preliminary test included the use of Rockwool to grow coriander for 14 days. Being a prototype, it is still necessary to optimize the design, fine-tune its operation beyond its initial feasibility to both, maximize yield and minimize cost, which implies compromising on these two conflicting objectives.Los sistemas hidropónicos existen desde hace ya varios años en una amplia variedad de diseños y configuraciones. El proyecto que aquí se describe comprende el diseño de un sistema hidropónico modular apilable para uso doméstico, con miras a que sea uno con alta productividad. Una impresora 3D se utilizó para desarrollar el prototipo que consta de elementos cilíndricos, cada uno con tres receptáculos. A los elementos cilíndricos apilables se les puede rotar con respecto de su eje, añadiendo así mayor flexibilidad de configuración. Convenientemente, la tapa del sistema está formada por medio elemento cilíndrico. Para la prueba preliminar que aquí se describe, se depositaron semillas de cilantro por un período de 14 días en Rockwool. En su fase prototípica, se determinó la factibilidad del sistema, aunque se reconoce que es aún necesario optimizar el diseño y afinar su operación. Esto implicará conciliar dos objetivos en conflicto: maximizar la productividad del sistema y minimizar su costo total

The reproductive capacity of Monk Parakeets Myiopsitta monachus is higher in their invasive range

Breeding parameters for Monk Parakeets Myiopsitta monachus nesting in Barcelona, Spain, were collected for 651 nests over five breeding seasons. This invasive population has a high reproductive capacity compared with the species in the native range: fledging success was double, the percentage of pairs attempting second broods three times higher and 55% of first-year birds bred compared with almost zero in South America

Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use

Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù

Educational and labor wastage of doctors in Mexico: towards the construction of a common methodology

BACKGROUND: This paper addresses the problem of wastage of the qualified labor force, which takes place both during the education process and when trained personnel try to find jobs in the local market. METHODS: Secondary sources were used, mainly the Statistical yearbooks of the National Association of Universities and Higher Education Institutions (ANUIES in Spanish). Also, the 2000 Population Census was used to estimate the different sources of labor market wastage. The formulas were modified to estimate educational and labor wastage rates. RESULTS: Out of every 1000 students who started a medical training in 1996, over 20% were not able to finish the training by 2000. Furthermore, out of every 1000 graduates, 31% were not able to find a remunerated position in the labor market that would enable them to put into practice the abilities and capacities obtained at school. Important differences can be observed between generalists and specialists, as well as between men and women. In the case of specialists and men, lower wastage rates can be observed as compared to the wastage rates of generalists and women. A large percentage of women dedicate themselves exclusively to household duties, which in labor terms represents a wastage of their capacity to participate in the production of formal health services. CONCLUSION: Women are becoming a majority in most medical schools, yet their participation in the labor market does not reflect the same trend. Among men, policies should be formulated to incorporate doctors in the specific health field for which they were trained. Regarding women, specific policies should target those who are dedicated full-time to household activities in order to create the possibility of having them occupy a remunerated job if they are willing to do so. Reducing wastage at both the educational and labor levels should improve the capacity of social investment, thereby increasing the capacity of the health system as a whole to provide services, particularly to those populations who are most in need

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

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