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Aims: To establish the common rules of exon combinatorics during RNA splicing. Study Design: Inferring a plausible statistical model of exon combinatorics from the annotated models of human genes during RNA splicing. Place and Duration of Study: Department of Genetics (Belarusian State University), Proteome and Genome Research Unit (Luxembourg Institute of Health), Department of Genetics (Lomonosov Moscow State University) and Moscow Center of Experimental Embryology and Reproductive Biotechnologies, between January 2017 and July 2019. Methodology: We used human mRNA and EST sequences from GenBank (1093522 unique records in total) and linear models of the human genes from Ensembl (58051 genes), AceView (72384 genes), ECgene (57172 genes), NCBI RefSeq (54262 genes), UCSC Genome Browser (58037 genes) and VEGA (54950 genes) to calculate a combinatorial index of human exons. We inferred the most plausible statistical model describing the distribution of combinatorial index of human exons using Clauset’s mathematical formalism. Predictors of the combinatorial index values and functional outcomes of the predefined behavior of exons during splicing were also determined. Results: Power-law is the most plausible statistical model describing the combinatorics of exons during RNA splicing. The combinatorial index of human exons is defined by more than 90% by the 138 features that have different importance. The most important of these features are the abundance of exon in transcripts, the strength of splice sites, the rank of exon in transcripts and the type of exon. Analysis of the marginal effects shows that different values of the same feature have unequal influence on the combinatorial index of human exons. Power-law behavior of exons during RNA splicing pre-determines structural diversity of transcripts, low sensitivity of splicing process to random perturbations and its high vulnerability to manipulation with highly combinative exons. Conclusion: Exons widely involved in alternative splicing are a part of the common power-law phenomenon in human cells. The power-law behavior of exons during RNA splicing gives the unique characteristics to human genes.
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Resumen Aunque los inselbergs son afloramientos rocosos icónicos con un alto valor biogeográfico, poco se conoce sobre los mecanismos responsables de la estructuración de comunidades vegetales. El objetivo de esta investigación fue evaluar cómo el tamaño de los parches de vegetación influye en la relación especie-área y distribución de la abundancia de especies de una comunidad en un inselberg del Monumento Natural "Piedra La Tortuga", región Guayana, Venezuela. Por este motivo, se establecieron tres preguntas de investigación: ¿Cuál es el efecto del tamaño de los parches sobre la riqueza de especies? ¿Qué tipo de modelo especie-área (SAR) presenta mejor ajuste en esos parches de vegetación? ¿Cómo es la distribución de las abundancias de las especies (SADs) es inducida por el tamaño de los parches? Se realizó un muestreo aleatorio estratificado en parches que oscilaron entre 0.34 y 14.8 m2, totalizando 40 unidades muestrales (226 m2). Todos los individuos encontrados en los 40 parches fueron identificados a nivel de especie. La composición florística en las diferentes muestras estuvo representada por 19 familias, 22 géneros y 24 especies, de las cuales 50 % son endémicas de inselbergs y dos están amenazadas de extinción. Se identificaron dos grupos de tamaños de parches (grandes 8-15 m2 y pequeños ≤ 7.9 m2) en relación a la abundancia y composición de especies, con diferencias significativas entre los grupos. Las curvas de acumulación de especies para cada grupo de tamaño de parche muestran una tendencia contrastante con marcadas diferencias en la riqueza observada entre los grupos de tamaños de parches. Las curvas de los modelos SADs tuvieron un ajuste significativo de la serie geométrica en las dos categorías de parches. El modelo SAR de la función potencia presentó los mejores ajustes especie-área, donde el aumento del área de los parches explicó un 82 % de la variación en el aumento del número de especies. Los resultados de este estudio demuestran por primera vez como el tamaño de los parches de vegetación de un inselberg tropical tiene una fuerte influencia sobre la riqueza, distribución de la abundancia y composición de especies. Así mismo, se determinó que el modelo geométrico SAD presentó el mejor ajuste en la comunidad en función del tamaño de los parches como un indicador de recursos, donde la abundancia de una especie puede ser equivalente a una proporción del espacio ocupado. También se presume que los cambios de tamaño de los parches, podría estar asociado con la disponibilidad de nutrientes y agua, como ha sido demostrado en otros ambientes de tierras secas. En algunos estudios se ha argumentado que la variación en la composición de especies entre los perfiles de vegetación de inselbergs tropicales está condicionada principalmente por la estructura del hábitat y el déficit hídrico. Sin embargo, no se había discutido cómo el tamaño de los parches de vegetación tiene un efecto en la riqueza. Los análisis SADs y SAR pueden proporcionar explicaciones complementarias sobre la estructuración de comunidades vegetales en inselbergs.
Abstract Although inselbergs are iconic rock outcrops with a high biogeographic value, little is known about drivers responsible for the plant community assembly. The aim of this research was to evaluate how the patch size distribution of vegetation influences the species-area relationship and species abundance distribution of a community in an inselberg of the "Piedra La Tortuga" Natural Monument of the Guayana region, Venezuela. In this context, three research questions were established: What is the effect of patch size on species richness? What species-area model (SAR) has the best fit in those vegetation patches? How is the distribution of species abundances (SADs) induced by the patch size distribution? A stratified random sampling was performed in patches ranging from 0.34 to 14.8 m2, totaling 40 sampling units (226 m2). All individuals found in the 40 patches were identified at species level. The floristic composition in the different samples was represented by 19 families, 22 genera and 24 species, of which 50 % are endemic to inselbergs and two, are threatened of extinction. Two groups of patch sizes were identified (large 8-15 m2 and small ≤ 7.9 m2) in relation to the abundance and composition of species. The species accumulation curves for each patch size group show a contrasting tendency with marked differences in the observed richness among patch size groups. The curves of the SADs models had a significant adjustment of the geometric series in the two categories of patches. The SAR model of the power function presented the best species-area adjustments, where the increase in patch area accounted for 82 % of the variation in the increase in the number of species. The results of this study demonstrate for the first time how vegetation patches of a tropical inselberg have a strong influence on richness, abundance distribution and species composition. Likewise, it was determined that the SAD geometric model presented the best fit in the community as a function of patch size as a resource indicator, where the abundance of a species can be equivalent to a proportion of the space occupied. It is also presumed that changes in patch sizes could be associated with nutrient and water availability, as has been demonstrated in other dryland environments. In some studies it has been argued that variation in species composition among vegetation profiles of tropical inselbergs is mainly conditioned by habitat structure and water deficit. However, it had not been discussed how the size of patches of vegetation has an effect on richness. SADs and SAR analyzes can provide complementary explanations on community assembly in inselbergs. Rev. Biol. Trop. 66(2): 937-951. Epub 2018 June 01.
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Bosques , Sedimentos Geológicos , Tabebuia , Dispersión de las Plantas , VenezuelaRESUMEN
Objective To study the spatial-temporal dynamical features of hand-foot-mouth disease (HFMD) in Shaanxi Province,so as to provide evidence for the development of relative prevention and control programs on HFMD.Methods Surveillance data of HFMD was collected from the China Information System for Diseases Control and Prevention from 2009 to 2013.Related data on population and gross domestic product (GDP) was obtained from Shaanxi Statistical Yearbook.Statistical tools as R3.4.1,ArcGIS 10.2 and SaTScan 9.2 software were used to describe the spatialtemporal distribution of the disease.Power-law method on spatial-temporal-multicomponent model was used to analyze the spatial-temporal evolution of the HFMD epidemics in Shaanxi Province.Results A total of 229 904 cases of HFMD were reported in Shaanxi Province from 2009 to 2013,with an average annual incidence as 122.50 per 100 000.Obvious seasonal characteristics were noticed,with 71.71％ of the total cases identified between April and July.Counties with high incidence were mainly distributed in the mid-and east parts of Guanzhong area.Through temporal and spatial scan statistics,we identified that Class Ⅰ clustering area was fixed to the central and southeast regions of Shaanxi province which were around Xi'an City between 2009 and 2013,with the relative risk (RR)as 2.24,ranging from 2.18 to 3.08.Results from Power-law analysis showed that the continuous follow-up impact from the previous HFMD epidemics appeared strong in Tongguan,Pucheng districts of Weinan City and Weiyang district of Xi'an,with autoregressive components as 1.14,0.97 and 0.89,respectively.The risk of HFMD seemed high in Huayin city,Changan and Yanta districts and with the endemic components as 5.08,4.12 and 4.08,respectively.Impact of the epidemics on nearby districts was largely seen in Lianhu district of Xi'an,Wugong district of Xianyang and Gaoling district of Xi'an with epidemic components as 2.12,2.08 and 1.77,respectively.The etiological constituents of HFMD were mainly Enterovirus 71 between 2009 and 2012,while HFMD was mainly caused by other entero-viruses,in 2013.Conclusion Significant spatial-temporal heterogeneity of HFMD was seen in Shaanxi province,which called for specific strategies to be developed in the highly endemic areas.
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Objective To study the spatial-temporal dynamical features of hand-foot-mouth disease (HFMD) in Shaanxi Province,so as to provide evidence for the development of relative prevention and control programs on HFMD.Methods Surveillance data of HFMD was collected from the China Information System for Diseases Control and Prevention from 2009 to 2013.Related data on population and gross domestic product (GDP) was obtained from Shaanxi Statistical Yearbook.Statistical tools as R3.4.1,ArcGIS 10.2 and SaTScan 9.2 software were used to describe the spatialtemporal distribution of the disease.Power-law method on spatial-temporal-multicomponent model was used to analyze the spatial-temporal evolution of the HFMD epidemics in Shaanxi Province.Results A total of 229 904 cases of HFMD were reported in Shaanxi Province from 2009 to 2013,with an average annual incidence as 122.50 per 100 000.Obvious seasonal characteristics were noticed,with 71.71％ of the total cases identified between April and July.Counties with high incidence were mainly distributed in the mid-and east parts of Guanzhong area.Through temporal and spatial scan statistics,we identified that Class Ⅰ clustering area was fixed to the central and southeast regions of Shaanxi province which were around Xi'an City between 2009 and 2013,with the relative risk (RR)as 2.24,ranging from 2.18 to 3.08.Results from Power-law analysis showed that the continuous follow-up impact from the previous HFMD epidemics appeared strong in Tongguan,Pucheng districts of Weinan City and Weiyang district of Xi'an,with autoregressive components as 1.14,0.97 and 0.89,respectively.The risk of HFMD seemed high in Huayin city,Changan and Yanta districts and with the endemic components as 5.08,4.12 and 4.08,respectively.Impact of the epidemics on nearby districts was largely seen in Lianhu district of Xi'an,Wugong district of Xianyang and Gaoling district of Xi'an with epidemic components as 2.12,2.08 and 1.77,respectively.The etiological constituents of HFMD were mainly Enterovirus 71 between 2009 and 2012,while HFMD was mainly caused by other entero-viruses,in 2013.Conclusion Significant spatial-temporal heterogeneity of HFMD was seen in Shaanxi province,which called for specific strategies to be developed in the highly endemic areas.
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We analyzed the statistical distribution of intra-specific local abundances for a set North American breeding bird species. We constructed frequency plots for every species and found that they showed long-tail power-law behavior, truncated at an upper abundance cut-off value. Based on finite size scaling arguments, we investigated whether frequency curves may be considered scaled copies of each other. Data collapse was possible after taking powers of the total abundance of each species, in order to correct deviations from the underlying universal finite size scaling function (UFSS). The UFSS power law exponent oscillated in time within the regime of unbounded variance, which is consistent with the wild fluctuations that characterize ecological phenomena. We speculate that our results may eventually be linked to other law-like macroecological phenomena, such as energetic constraints reported in allometric scaling.
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Animales , Aves/fisiología , Modelos Biológicos , Aves/anatomía & histología , Geografía , Densidad de Población , Especificidad de la EspecieRESUMEN
En este trabajo se analizó la degradación del poli(etilen tereftalato) variando la temperatura y la concentración de hidróxido de potasio en 1-butanol, manteniendo constante el tamaño y peso de la muestra. El intervalo de temperatura utilizada fue de 110 ºCa 150 ºC y las concentraciones de hidróxido de potasio en 1-butanol en el intervalo 0,4 a 4,4 molar. Para estas condiciones de concentración y temperatura se observó la degradación de un 99% de poli(etilen tereftalato) en un tiempo de una hora. Se obtuvieron dos fases: una orgánica y una sólida. La fase sólida es un polvo soluble en soluciones ácidas. Este producto degradado corresponde probablemente al tereftalato de potasio. A una temperatura de 150 ºC y una concentración de 3,34 M se estudió la cinética de degradación del poli(etilen tereftalato) en función del tiempo. A partir de los resultados y comparando con modelos matemáticos de degradación encontrados en la literatura, se propone que la degradación del poli(etilen tereftalato) sigue un modelo de degradación de power law.
In this work the degradation of poly(ethylene terephthalate) was analyzed by varying the temperature and the concentration of potassium hydroxide in 1-butanol holding constant the size and weight of the sample. The temperature range used was from 110ºC to 150ºC and concentrations of potassium hydroxide in 1-butanol in the range of 0,4 to 4,4 molar, obtaining 99% degradation of poly(ethylene terephthalate) in one hour. The temperature of 150°C and the concentration of 3,34 M were used to study the degradation of poly(ethylene terephthalate) as a function of time. We obtained two phases, an organic phase and solid phase. The solid phase is a soluble in acidic solutions. The solid phase probably corresponds to the of potassium terephthalate. From the results and comparing with models of degradation found in the literature this work suggests that poly(ethylene terephthalate) degradation reaction occurs type power law.
Neste trabalho, se analisou a degradação de poli(tereftalato de etileno) através da variação da temperatura e da concentração de hidróxido de potássio em 1-butanol, segurando o tamanho e o peso constante da amostra. A faixa de temperatura utilizada foi 110° C a 150° C e concentrações de hidróxido de potássio em 1-butanol, intervalo de 0,4-4,4 molar. Para que essas variações são 99% de degradação do poli(teref-talato de etileno) em um tempo de uma hora. Foram obtidas duas fases: uma fase orgânica e uma fase sólida. A fase sólida é um pó solúvel em soluções ácidas. Isso provavelmente corresponde ao produto degradado de tereftalato de potássio. Foram utilizadas uma temperatura de 150 °C e uma concentração de 3,34 M para estudar a cinética de degradação do poli(teref-talato de etileno) como uma função do tempo. A partir dos resultados e comparando com modelos matemáticos de degradação encontrados na literatura, se sugere que a degradação do poli(tereftalato de etileno) é um modelo de degradação do tipo lei de potência.