372 research outputs found
Contrasting population structure and demographic history of cereal aphids in different environmental and agricultural landscapes
Genetic diversity of populations has important ecological and evolutionary consequences, whose understanding is fundamental to improve the sustainability of agricultural production. Studies of how differences in agricultural management and environment influence the population structure of insect pests are central to predict outbreaks and optimise control programmes. Here, we have studied the population genetic diversity and evolution of Sitobion avenae and Sitobion miscanthi, which are among the most relevant aphid pests of cereals across Europe and Asia, respectively. We have used genotyping by sequencing (GBS) to identify genome-wide single nucleotide polymorphisms (SNPs) to infer the geographic structure and migration patterns. In the present study, we show that the population structure in present day populations are different from that described in previous studies, which suggests that they have evolved recently possibly as a response to human-induced changes in agriculture. This study shows that S. avenae in England is predominantly parthenogenetic and there has been a demographic and spatial expansion of a single genetic cluster, which could correspond with the insecticide-resistance superclone identified in previous studies. Conversely, in China, S. miscanthi populations are mostly cyclical parthenogenetic, with one sexual stage in autumn to produce overwintering eggs, and there are six genetically differentiated subpopulations and high genetic differentiation between geographic locations, which suggests that further taxonomical research is needed. Unlike S. avenae in England, there is no evidence for insecticide resistance and there is no predominance of a single lineage in S. miscanthi in China
ANALISIS NILAI SOSIAL PADA NOVEL BILA MALAM BERTAMBAH MALAM KARYA PUTU WIJAYA DENGAN PENDEKATAN MIMETIK
Every literary work must have the social values of life contained in it, whether conveyed implicitly or explicitly. Like the novel Bila Malam Bertambah Malam by Putu Wijaya, it contains many social values and so on. With these problems, this research article is written to discuss "Analysis of Social Values in the novel Bila Malam Bertambah Malam by Putu Wijaya using the mimetic approach”. This research was conducted using qualitative descriptive research methods. Data collection techniques carried out, in the form of documentation, as well as research instruments were the researchers themselves using a check list of the classification of research materials and notes of observations. The data analysis technique in this study is a descriptive interpretive technique, where the researcher tries to describe the opinions and views that are on an object of research. This article aims to find out the social values contained in the novel Bila Malam Bertambah Malam by Putu Wijaya. The results of this study indicate that social problems cannot be separated from the relationships that accompany them. These relationships include human problems with humans, human problems with oneself and human problems with culture
Comparación de la eficacia y seguridad diagnóstica entre el estudio isotópico hepatobiliar y la ecografía en la colecistitis aguda
Hemos estudiado en 67 pacientes con el diagnóstico de colecistitis aguda (CA) confirmado mediante intervención quirúrgica precoz, la sensibilidad diagnóstica del estudio isotópico con HIDA comparándola con la de la ecografía. El estudio se llevó a cabo de forma retrospectiva. La sensibilidad del estudio isotópico (97%) ha sido claramente superior a la de la ecografía (82%), aunque esta última ofrece ventajas en cuanto a la rapidez y economía de valor indudable. Asimismo hemos intentado establecer la seguridad de ambas técnicas en el diagnóstico de la coledocolitiasis asociada a la CA, que en nuestro estudio ha mostrado una incidencia alta (26%), siendo mala para ambas técnicas; la sensibilidad en este caso para la ecografía ha sido del 50% mientras que para el HIDA ha sido del 12,5%. Por tanto creemos conveniente realizar como primer estudio diagnóstico para la confirmación de la sospecha clínica de CA una ecografía abdominal, reservando la escintigrafía para los casos, por otra parte numéricamente apreciables, en que persista la duda diagnóstica. Asimismo recomendamos la realización de colangiografía intraoperatoria debido a la deficiente fiabilidad que ambas exploraciones han demostrado en la detección de coledocolitiasis en los pacientes con C
High pressure pre-treatments promote higher rate and degree of enzymatic hydrolysis of cellulose
The effect of high pressure (HP) pre-treatments on the subsequent enzymatic hydrolysis of cellulose from bleached kraft Eucalyptus globulus pulp by cellulase from Tricoderma viride was evaluated. Pressure pre-treatments of 300 and 400 MPa during 5–45 min, lead to both an increased rate and degree of hydrolysis, reaching values ranging from 1.5- to 1.9-fold, quantified by the formation of reducing sugars. Both the pressure and time under pressure influenced the enzymatic hydrosability of the cellulosic pulps, with the former being more important. The results indicate that the pressure pre-treatments promoted an increased accessibility of cellulose towards cellulase in the cell wall. The results obtained open promising possibilities, to contribute to overcome conventional limitations of enzymatic cellulose hydrolysis for the production of fermentable glucose, for the production of second generation bioethanol and chemicals by enhancement of both rate and yield of hydrolysis. The results are also of interest for the preparation of “pressure engineered” celullose with incremented tailored hydrolysis patterns
Population genetic structure and predominance of cyclical parthenogenesis in the bird cherry–oat aphid Rhopalosiphum padi in England
Genetic diversity is determinant for pest species' success and vector competence. Understanding the ecological and evolutionary processes that determine the genetic diversity is fundamental to help identify the spatial scale at which pest populations are best managed. In the present study, we present the first comprehensive analysis of the genetic diversity and evolution of Rhopalosiphum padi, a major pest of cereals and a main vector of the barley yellow dwarf virus (BYDV), in England. We have used a genotyping by sequencing approach to study whether i) there is any underlying population genetic structure at a national and regional scale in this pest that can disperse long distances; ii) the populations evolve as a response to environmental change and selective pressures, and; iii) the populations comprise anholocyclic lineages. Individual R. padi were collected using the Rothamsted Insect Survey's suction‐trap network at several sites across England between 2004 and 2016 as part of the RIS long‐term nationwide surveillance. Results identified two genetic clusters in England that mostly corresponded to a North – South division, although gene flow is ongoing between the two subpopulations. These genetic clusters do not correspond to different life cycles types, and cyclical parthenogenesis is predominant in England. Results also show that there is dispersal with gene flow across England, although there is a reduction between the northern and southern sites with the Southwestern population being the most genetically differentiated. There is no evidence for isolation‐by‐distance and other factors like primary host distribution, uncommon in the south and absent in the southwest, could influence the dispersal patterns. Finally, results also show no evidence for the evolution of the R. padi population, and it is demographically stable despite the ongoing environmental change. These results are discussed in view of their relevance to pest management and the transmission of BYDV
Effect of hemicellulose liquid phase on the enzymatic hydrolysis of autohydrolyzed Eucalyptus globulus wood
In this work, Eucalyptus globulus wood was pretreated under non-isothermal autohydrolysis process at 210, 220, and 230 °C, obtaining a pretreated solid with high cellulose content and a hemicellulosic liquid phase (HLP) containing mainly xylose, acetic acid, furfural, xylooligosaccharides, and phenolic compounds. The maximum concentration of xylooligosaccharides (8.97 g/L) and phenolic compounds (2.66 g/L) was obtained at 210 and 230 °C, respectively. To evaluate the effect of HLP addition on the enzymatic hydrolysis using unwashed pretreated solid as substrate, different proportions of HLP were studied. Also, in order to use the whole slurry on enzymatic hydrolysis, the supplementation of xylanases was evaluated. Glucose concentration of 107.49 g/L (corresponding to 74.65 % of conversion) was obtained using pretreated solid at 220 °C liquid/solid ratio (LSR) of 4 g/g and enzyme solid ratio (ESR) of 25 FPU/gwithout the addition of HLP. Thus, it was shown that the unwashed pretreated solids are susceptible to enzymatic hydrolysis contributing to reduce operational cost (water consumption). Additionally, the influence of the inhibitory compounds in the HLP was shown to affect the enzymatic hydrolysis. Results indicated that 82.52 g/L of glucose (59.37 % of conversion) was obtained, using 100 % of HLP at LSR of 4 g/g and ESR of 16 FPU/g at 210 °C of pretreated solid. However, a positive effect was shown on the enzymatic hydrolysis when the xylanases were added using 100 % of HLP, increasing to 35 and 27 % in the glucose production with respect to whole slurry without addition of xylanases.The authors A. Romani and F. B. Pereira thank to the Portuguese Foundation for Science and Technology (FCT, Portugal) for their fellowships (grant number, SFRH/BPD/77995/2011 and SFRH/BD/64776/2009, respectively)
Hábitos de actividad física y conductas sedentarias en escolares de Educación Primaria
The objective of the present study is to describe the anthropometric characteristics and lifestyle in Primary School (PS) students and to observe if there are differences in the variables analyzed regarding sex, school grade, educational cycle, number of weekly Physical Education sessions and type of educational center. In this study, 793 PS students participated. Among the results obtained, significantly higher values were observed in the group of boys, compared to the group of girls, in the weekly practice of physical exercise (p <0.01) and in the recreative use of screens on weekends (p <0.01). Significant differences were also found depending on the school grade, the educational cycle and the type of educational center. These results show the importance of understanding the specific characteristics of the groups of schoolchildren, with the objective of being efficient in the necessary implementation of policies encouraging the practice of PA.Los objetivos del presente estudio fueron describir las características antropométricas y los hábitos de vida de escolares de Educación Primaria Obligatoria (EPO) y observar si existen diferencias en las variables analizadas atendiendo al sexo, curso escolar, internivel, número de sesiones semanales de Educación Física y tipo de centro educativo. En este estudio participaron 793 estudiantes de EPO. Entre los resultados obtenidos, se observaron valores significativamente más altos en el grupo de chicos con respecto al grupo de chicas en la práctica semanal de AF reglada (p < 0,01) y en el uso ocioso de pantallas los fines de semana (p < 0,01). También se hallaron diferencias significativas atendiendo al curso, internivel y tipo de centro. Estos resultados evidencian la importancia de conocer las características específicas de los grupos de escolares, con el objetivo de ser eficientes en la necesaria implementación de políticas de fomento de la práctica de AF
¿Deficiencia, discapacidad o identidad cultural?: interpretación de la sordera y respuestas en el sistema educativo en España
Applied science facilitates the large-scale expansion of protected areas in an Amazonian hot spot
Meeting international commitments to protect 17% of terrestrial ecosystems worldwide will require \u3e3 million square kilometers of new protected areas and strategies to create those areas in a way that respects local communities and land use. In 2000–2016, biological and social scientists worked to increase the protected proportion of Peru’s largest department via 14 interdisciplinary inventories covering \u3e9 million hectares of this megadiverse corner of the Amazon basin. In each landscape, the strategy was the same: convene diverse partners, identify biological and sociocultural assets, document residents’ use of natural resources, and tailor the findings to the needs of decision-makers. Nine of the 14 landscapes have since been protected (5.7 million hectares of new protected areas), contributing to a quadrupling of conservation coverage in Loreto (from 6 to 23%). We outline the methods and enabling conditions most crucial for successfully applying similar campaigns elsewhere on Earth
Optimization of xylanase production by filamentous fungi in solid state fermentation and scale-up to horizontal tube bioreactor
Five microorganisms, namely Aspergillus niger CECT 2700, A. niger CECT 2915, A. niger CECT 2088, Aspergillus terreus CECT 2808, and Rhizopus stolonifer CECT 2344, were grown on corncob to produce cell wall polysaccharide-degrading enzymes, mainly xylanases, by solid-state fermentation (SSF). A. niger CECT 2700 produced the highest amount of xylanases of 504±7 U/g dry corncob (dcc) after 3 days of fermentation. The optimization of the culture broth (5.0 g/L NaNO3, 1.3 g/L (NH4)2SO4, 4.5 g/L KH2PO4, and 3 g/L yeast extract) and operational conditions (5 g of bed loading, using an initial substrate to moistening medium of 1:3.6 (w/v)) allowed increasing the predicted maximal xylanase activity up to 2,452.7 U/g dcc. However, different pretreatments of materials, including destarching, autoclaving, microwave, and alkaline treatments, were detrimental.
Finally, the process was successfully established in a laboratory-scale horizontal tube biore- actor, achieving the highest xylanase activity (2,926 U/g dcc) at a flow rate of 0.2 L/min. The result showed an overall 5.8-fold increase in xylanase activity after optimization of culture media, operational conditions, and scale-up.We are grateful to the Spanish Ministry of Science and Innovation for the financial support of this work (project CTQ2011-28967), which has partial financial support from the FEDER funds of the European Union; to the Leonardo da Vinci Programme for founding the stay of Felisbela Oliveira in Vigo University; to MAEC-AECID (Spanish Government) for the financial support for Perez-Bibbins, B. and to Spanish Ministry of Education, Culture and Sports for Perez-Rodriguez's FPU; and to Solla E. and Mendez J. (CACTI-University of Vigo) for their excellent technical assistance in microscopy
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