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- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 7. |
- Zuntini, Alexandre R., et al.
(författare)
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Phylogenomics and the rise of the angiosperms
- 2024
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Ingår i: NATURE. - 0028-0836 .- 1476-4687. ; 629, s. 843-850
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Tidskriftsartikel (refereegranskat)abstract
- Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods(1,2). A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome(3,4). Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins(5-7). However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes(8). This 15-fold increase in genus-level sampling relative to comparable nuclear studies(9) provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade.
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| 8. |
- Casanueva, Carlos, 1981-
(författare)
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Análisis dinámico de un eje de ferrocarril con capacidad de cambio de ancho automático
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- El objetivo de la presente tesis es la mejora de los actuales ejes de ancho variable para su circulación por vías de alta velocidad (AV) a velocidades de hasta 300km/h. En la actualidad los vehículos con ejes de ancho variable no sobrepasan los 250km/h de velocidad de servicio en vías de AV, lo que supone un claro desaprovechamiento de recursos y dificultades de gestión del tráfico para el gestor de la infraestructura a causa de las distintas velocidades punta de los diferentes trenes. Los modelos ferroviarios convencionales no tienen en cuenta la flexibilidad asociada a los ejes y suponen que éstos son lo suficientemente rígidos como para no necesitar una modelización que tenga en cuenta su deformación estructural. Sin embargo, en los ejes de ancho variable, que poseen tanto mecanismos que permiten el desplazamiento lateral de rueda respecto al cuerpo de eje como mecanismos de bloqueo de dicho desplazamiento, tienen influencia diversas holguras, rozamiento entre superficies, y componentes intermedios entre ruedas y cuerpo de eje. Estos efectos provocan una flexibilización de la conexión entre ruedas y cuerpo de eje que es necesario estudiar. Por otra parte, en el caso de los ejes de ancho variable de cuerpo de eje no rotativo sus menores solicitaciones a fatiga permiten una importante reducción del diámetro del cuerpo de eje. Esto provoca una flexibilidad adicional muy superior a la de los ejes convencionales. Para el estudio de la influencia de este aumento de flexibilidad en el comportamiento dinámico del eje, en primer lugar se determina qué tipo de modelo permite la correcta representación de los efectos presentes en los análisis dinámicos. Además, se analiza en profundidad el comportamiento del eje de ancho variable, para facilitar el posterior estudio y simplificaciones, así como identificar los componentes críticos del mecanismo. En segundo lugar se calculan las relaciones esfuerzo-deformación para los distintos componentes del sistema: conjunto de rodamientos, cuerpo de eje, mecanismos de anclaje, etc. Dichas características se introducen en un modelo multicuerpo simplificado que es capaz de representar tanto ejes de ancho variable flexibles como ejes convencionales flexibles. Por último se realiza un análisis de la influencia de dichas características en el comportamiento dinámico del vehículo, así como el grado de influencia de cada una de ellas. Además se proponen posibles mejoras del sistema para mejorar sus prestaciones a altas velocidades.
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| 9. |
- Yaghootkar, Hanieh, et al.
(författare)
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Genetic Studies of Leptin Concentrations Implicate Leptin in the Regulation of Early Adiposity
- 2020
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 69:12, s. 2806-2818
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Tidskriftsartikel (refereegranskat)abstract
- Leptin influences food intake by informing the brain about the status of body fat stores. Rare LEP mutations associated with congenital leptin deficiency cause severe early-onset obesity that can be mitigated by administering leptin. However, the role of genetic regulation of leptin in polygenic obesity remains poorly understood. We performed an exome-based analysis in up to 57,232 individuals of diverse ancestries to identify genetic variants that influence adiposity-adjusted leptin concentrations. We identify five novel variants, including four missense variants, in LEP, ZNF800, KLHL31, and ACTL9, and one intergenic variant near KLF14. The missense variant Val94Met (rs17151919) in LEP was common in individuals of African ancestry only, and its association with lower leptin concentrations was specific to this ancestry (P = 2 × 10-16, n = 3,901). Using in vitro analyses, we show that the Met94 allele decreases leptin secretion. We also show that the Met94 allele is associated with higher BMI in young African-ancestry children but not in adults, suggesting that leptin regulates early adiposity.
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| 10. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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