The study area is located between the cities of Comitan (16°10'43"N and 92°04'20''W) a city with 150,000 inhabitants and La Esperanza (16°9'15''N and 91°...The study area is located between the cities of Comitan (16°10'43"N and 92°04'20''W) a city with 150,000 inhabitants and La Esperanza (16°9'15''N and 91°52'5''W) a town with 3000 inhabitants. Both weather stations are 30 km from each other in the Chiapas State, México. 54 years of daily records of the series of maximum (<em>t</em><sub>max</sub>) and minimum temperatures (<em>t</em><sub>min</sub>) of the weather station 07205 Comitan that is on top of a house and 30 years of daily records of the weather station 07374 La Esperanza were analyzed. The objective is to analyze the evidence of climate change in the Comitan valley. 2.07% and 19.04% of missing data were filled, respectively, with the WS method. In order to verify homogeneity three methods were used: Standard Normal Homogeneity Test (SNHT), the Von Neumann method and the Buishand method. The heterogeneous series were homogenized using climatol. The trends of <em>t</em><sub>max</sub> and <em>t</em><sub>min</sub> for both weather stations were analyzed by simple linear regression, Sperman’s rho and Mann-Kendall tests. The Mann-Kendal test method confirmed the warming trend at the Comitan station for both variables with <em>Z<sub>MK</sub></em> statistic values equal to 1.57 (statistically not significant) and 4.64 (statistically significant). However, for the Esperanza station, it determined a cooling trend for tmin and a slight non-significant warming for <em>t</em><sub>max</sub> with a <em>Z</em><sub><em>MK</em></sub> statistic of -2.27 (statistically significant) and 1.16 (statistically not significant), for a significance level <em>α</em> = 0.05.展开更多
One of the collective phenomena that has allowed a theoretical debate on the social movements in the current context is the neo-Zapatista of Chiapas. From a discussion on some significant events and possible interpret...One of the collective phenomena that has allowed a theoretical debate on the social movements in the current context is the neo-Zapatista of Chiapas. From a discussion on some significant events and possible interpretations about their identities, strategies, demands and speeches, the aim is to place the movement in a structural dynamics that will acquire different views. In apparent confirmation of an ＂identitarian community of resistance＂, the neo-Zapatismo seems to move toward a new scenario, in which ＂your chance＂ is configured from its structural flexibility and fluidity. In this way, the neo-Zapatista movement seems to confirm that the theoretical antinomies on the social movements relating to the American school, its emphasis on ＂strategy＂ of collective actions, and the ones referring to the European version, emphasizing the dimension of ＂identity＂, cannot be considered completely contradictory. The neo-Zapatismo has shown that a particular strategy developed a specific corresponding identitarian construction, and vice versa.展开更多
Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.T...Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method(release cutting,and thinning)in comparison with an unharvested old-secondary forest in southern Mexico.For each treatment,richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated.We calculated the true diversity(Hill numbers)and beta diversity using the Jaccard coefficient of similarity,and generated rank abundance curves per taxonomic epiphyte group(bromeliads,orchids,ferns and others).For each treatment,the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models.Results:We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks.The greatest species richness(^(0)D)was recorded in the old-secondary forest.Fewer common(^(1)D)and dominant(^(2)D)species were recorded in the release cutting than in the other treatments.Epiphyte diversity and biomass were both slightly related to host tree basal area.Composition of epiphytes was similar(60%)among treatments,although orchids,bromeliads,and other families were more diverse in the old-secondary forest.Most bromeliad species were shared across all treatments,although orchids presented the most exclusive species in the unharvested forest.The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments,followed by the orchid Camaridium densum.Generalized linear models indicated that epiphyte diversity was significantly related to treatment,and epiphyte biomass to basal area of host trees.Conclusions:Although forest management affects diversity,composition,and abundance of vascular epiphytes,most of their diversity and biomass can be maintained despite timber harvesting.This requires sparing some mature oaks during logging,as they contribute to conservation,establishment,and development of epiphytic communities,and maintaining untreated areas as a source of propagules for these communities.展开更多
A total of 8 strong earthquakes with M S≥7.0 occurred in 2017(from January 1 to December 31,2017)throughout the world,according to the China Seismic Network,including one with M S≥8.0,i.e.,the great earthquake with ...A total of 8 strong earthquakes with M S≥7.0 occurred in 2017(from January 1 to December 31,2017)throughout the world,according to the China Seismic Network,including one with M S≥8.0,i.e.,the great earthquake with M S8.2 which occurred on September 8,2017 in Chiapas,Mexico(Fig.1).The 2017 M S8.2 Chiapas,Mexico earthquake was located in the east of the Circum-Pacific Seismic Belt.The mainshock was normal type and the rupture was unilateral along the NW direction,with maximum intensityⅨ.Features of global seismicity of M S≥7.0 in 2017 are as follows.展开更多
文摘The study area is located between the cities of Comitan (16°10'43"N and 92°04'20''W) a city with 150,000 inhabitants and La Esperanza (16°9'15''N and 91°52'5''W) a town with 3000 inhabitants. Both weather stations are 30 km from each other in the Chiapas State, México. 54 years of daily records of the series of maximum (<em>t</em><sub>max</sub>) and minimum temperatures (<em>t</em><sub>min</sub>) of the weather station 07205 Comitan that is on top of a house and 30 years of daily records of the weather station 07374 La Esperanza were analyzed. The objective is to analyze the evidence of climate change in the Comitan valley. 2.07% and 19.04% of missing data were filled, respectively, with the WS method. In order to verify homogeneity three methods were used: Standard Normal Homogeneity Test (SNHT), the Von Neumann method and the Buishand method. The heterogeneous series were homogenized using climatol. The trends of <em>t</em><sub>max</sub> and <em>t</em><sub>min</sub> for both weather stations were analyzed by simple linear regression, Sperman’s rho and Mann-Kendall tests. The Mann-Kendal test method confirmed the warming trend at the Comitan station for both variables with <em>Z<sub>MK</sub></em> statistic values equal to 1.57 (statistically not significant) and 4.64 (statistically significant). However, for the Esperanza station, it determined a cooling trend for tmin and a slight non-significant warming for <em>t</em><sub>max</sub> with a <em>Z</em><sub><em>MK</em></sub> statistic of -2.27 (statistically significant) and 1.16 (statistically not significant), for a significance level <em>α</em> = 0.05.
文摘One of the collective phenomena that has allowed a theoretical debate on the social movements in the current context is the neo-Zapatista of Chiapas. From a discussion on some significant events and possible interpretations about their identities, strategies, demands and speeches, the aim is to place the movement in a structural dynamics that will acquire different views. In apparent confirmation of an ＂identitarian community of resistance＂, the neo-Zapatismo seems to move toward a new scenario, in which ＂your chance＂ is configured from its structural flexibility and fluidity. In this way, the neo-Zapatista movement seems to confirm that the theoretical antinomies on the social movements relating to the American school, its emphasis on ＂strategy＂ of collective actions, and the ones referring to the European version, emphasizing the dimension of ＂identity＂, cannot be considered completely contradictory. The neo-Zapatismo has shown that a particular strategy developed a specific corresponding identitarian construction, and vice versa.
基金This study received research funding from the Rufford Foundation(Grant No.25259-1)from federal funds allotted to ECOSUR(NRM).
文摘Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method(release cutting,and thinning)in comparison with an unharvested old-secondary forest in southern Mexico.For each treatment,richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated.We calculated the true diversity(Hill numbers)and beta diversity using the Jaccard coefficient of similarity,and generated rank abundance curves per taxonomic epiphyte group(bromeliads,orchids,ferns and others).For each treatment,the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models.Results:We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks.The greatest species richness(^(0)D)was recorded in the old-secondary forest.Fewer common(^(1)D)and dominant(^(2)D)species were recorded in the release cutting than in the other treatments.Epiphyte diversity and biomass were both slightly related to host tree basal area.Composition of epiphytes was similar(60%)among treatments,although orchids,bromeliads,and other families were more diverse in the old-secondary forest.Most bromeliad species were shared across all treatments,although orchids presented the most exclusive species in the unharvested forest.The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments,followed by the orchid Camaridium densum.Generalized linear models indicated that epiphyte diversity was significantly related to treatment,and epiphyte biomass to basal area of host trees.Conclusions:Although forest management affects diversity,composition,and abundance of vascular epiphytes,most of their diversity and biomass can be maintained despite timber harvesting.This requires sparing some mature oaks during logging,as they contribute to conservation,establishment,and development of epiphytic communities,and maintaining untreated areas as a source of propagules for these communities.
文摘A total of 8 strong earthquakes with M S≥7.0 occurred in 2017(from January 1 to December 31,2017)throughout the world,according to the China Seismic Network,including one with M S≥8.0,i.e.,the great earthquake with M S8.2 which occurred on September 8,2017 in Chiapas,Mexico(Fig.1).The 2017 M S8.2 Chiapas,Mexico earthquake was located in the east of the Circum-Pacific Seismic Belt.The mainshock was normal type and the rupture was unilateral along the NW direction,with maximum intensityⅨ.Features of global seismicity of M S≥7.0 in 2017 are as follows.
