BACKGROUND A progressive decrease in exclusive breastfeeding(BF)is observed in Latin America and the Caribbean compared with global results.The possibility of being breastfed and continuing BF for>6 months is lower...BACKGROUND A progressive decrease in exclusive breastfeeding(BF)is observed in Latin America and the Caribbean compared with global results.The possibility of being breastfed and continuing BF for>6 months is lower in low birth weight than in healthy-weight infants.AIM To identify factors associated with BF maintenance and promotion,with particular attention to low-and middle-income countries,by studying geographic,socioeconomic,and individual or neonatal health factors.METHODS A scoping review was conducted in 2018 using the conceptual model of social determinants of health published by the Commission on Equity and Health Inequalities in the United States.The extracted data with common characteristics were synthesized and categorized into two main themes:(1)Sociodemographic factors and proximal determinants involved in the initiation and maintenance of BF in low-birth-weight term infants in Latin America;and(2)individual characteristics related to the self-efficacy capacity for BF maintenance and adherence in low-birth-weight term infants.RESULTS This study identified maternal age,educational level,maternal economic capacity,social stratum,exposure to BF substitutes,access to BF information,and quality of health services as mediators for maintaining BF.CONCLUSION Individual self-efficacy factors that enable BF adherence in at-risk populations should be analyzed for better health outcomes.展开更多
Traditional Chinese medicine(TCM) arrived from China to Latin America and the Caribbean in the 1840s due to the massive migration of Chinese people to the region. In a few years, the press noticed the presence of Chin...Traditional Chinese medicine(TCM) arrived from China to Latin America and the Caribbean in the 1840s due to the massive migration of Chinese people to the region. In a few years, the press noticed the presence of Chinese herbalists practicing in different cities and countries regardless of the demographic weight of the Chinese community. The fascination with Chinese doctors implicated not only the press but also the literature, a phenomenon particularly observed in Cuba. In the first decades of the 20th century, the reactivation of Chinese immigration to the region fostered an anti-Chinese climate that materialized in more significant migratory restrictions and control of their businesses, such as what happened with Chinese herbalists. These herbalists who practiced inside and outside the Chinese community started to object to criticism and persecution by the conservative press and professional doctors. Despite this, Chinese doctors will continue to maintain their support of a significant number of ill persons. This work seeks to illuminate the historical relevance of TCM in Latin America and the Caribbean, focusing on the cases of Peru, Chile, and Cuba. This last country was far from China culturally and geographically, but as in many other small towns in the region, Chinese medicine presented an alternative to the treatment of illnesses.展开更多
The genus Thuja is ideal for investigating the genetic basis of the East Asia-North America disjunction.The biogeographical background of the genus is debatable and an adaptive strategy is lacking.Through the analysis...The genus Thuja is ideal for investigating the genetic basis of the East Asia-North America disjunction.The biogeographical background of the genus is debatable and an adaptive strategy is lacking.Through the analysis and mining of comparative transcriptomes,species differentiation and positively selected genes(PSGs)were identified to provide information for understanding the environmental adaptation strategies of the genus Thuja.De novo assembly yielded 44,397-74,252 unigenes of the five Thuja species with contig N50length ranging from 1,559 to 1,724 bp.Annotations revealed a similar distribution of functional categories among them.Based on the phylogenetic trees constructed using the transcriptome data,T.sutchuenensis was divided first,followed by T.plicata and T.occidentalis.The final differentiation of T.koraiensis and T.standishii formed a clade.Enrichment analysis indicated that the PSGs of the North American Thuja species were involved in plant hormone signal transduction and carbon fixation of photosynthetic organisms pathways.The PSGs of East Asian Thuja were related to phenolic,alkaloid,and terpenoid synthesis,important stress-resistant genes and could increase plant resistance to external environmental stresses.This study discovered numerous aroma synthetic-related PSGs including terpene synthase(TPS)genes and lipid phosphate phosphatase 2(LPP2),associated with the synthetic aroma of T.sutchuenensis.Physiological indicators,such as the contents of soluble sugars,total chlorophyll,total phenolics,and total flavonoids were determined,which are consistent with the PSGs enrichment pathways associated with adaptive strategies in the five Thuja species.The results of this study provide an important basis for future studies on conservation genetics.展开更多
Clear and data-driven bioregionalizations can provide a framework to test hypotheses and base biodiversity conservation.Here we used occurrence and abundance data in combination with objective analytical methods to pr...Clear and data-driven bioregionalizations can provide a framework to test hypotheses and base biodiversity conservation.Here we used occurrence and abundance data in combination with objective analytical methods to propose two bioregionalization schemes for tree species of the Cerrado and the Pantanal in South America.We also evaluated the contribution of three sets of determinants of the occurrence-and abundance-based subregions.We compiled data on tree species composition from 894 local assemblages based on species occurrences,and from 658 local assemblages based on species abundances.We used an unconstrained community-level modelling approach and clustering techniques to identify and map tree subregions for the occurrence and the abundance data sets,separately.Hierarchical clustering analyses were conducted to investigate floristic affinities between the subregions and to map broader floristic regions.We used multinomial logistic regression models,deviance partitioning,and rank-sum tests to assess the main subregion correlates.We identified 18 occurrence-and four abundance-based subregions in the Cerrado-Pantanal.The hierarchical classifications grouped the occurrence-based subregions into nine floristic zones and abundance-based subregions into two broad floristic zones.Variation in subregions were explained mainly by environmental factors and spatial structure in both occurrence and abundance data sets.The occurrence-and abundance-based subregions are complementary approaches to disentangle macroecological patterns and to plan conservation efforts in the Cerrado and the Pantanal.Our findings based on occurrence data revealed more complex and interdigitated boundaries between subregions of tree species than previously reported.The environment,historical stability,and human effects act in a synergetic way on the distribution of the subregions.Finally,the relevance of contemporary environmental factors to the subregion patterns we found alert us to the profound impact global warming may have on the spatial organization of the Cerrado-Pantanal tree flora.展开更多
Understanding the mechanisms underlying plant responses to climate change is an important step toward developing effective mitigation strategies. Polyploidy is an important evolutionary trait that can influence the ca...Understanding the mechanisms underlying plant responses to climate change is an important step toward developing effective mitigation strategies. Polyploidy is an important evolutionary trait that can influence the capacity of plants to adapt to climate change. The environmental flexibility of polyploids suggests their resiliency to climate change, however, such hypotheses have not yet received empirical evidence. To understand how ploidy level may influence response to climate change, we modeled the current and future distribution of 54 Crataegus species under moderate to severe environments and compared the range change between diploids and polyploids. The majority of studied species are predicted to experience considerable range expansion. We found a negative interaction between ploidy and ecoregions in determining the response to climate change. In extreme environments, polyploids are projected to experience a higher range expansion than diploids with climate change, while the opposite is true for moderate environments. The range expansion of Crataegus species can be attributed to their tolerance for a wide range of environmental conditions. Despite the higher tolerance of polyploids to extreme environments, they do not necessarily outperform diploids in moderate environments, which can be attributed to the varying nature of species interactions along a stress gradient.展开更多
President Xi Jinping’s America trip from November 14 to 17,including his talks with U.S.President Joe Biden and his attendance at the 30th APEC Economic Leaders’Meeting in San Francisco,is widely believed to have ad...President Xi Jinping’s America trip from November 14 to 17,including his talks with U.S.President Joe Biden and his attendance at the 30th APEC Economic Leaders’Meeting in San Francisco,is widely believed to have added stability to China-U.S.relations,brought new impetus to Asia-Pacific cooperation and injected positive energy into the international and regional landscape.展开更多
South America’s climatic diversity is a product of its vast geographical expanse, encompassing tropical to subtropical latitudes. The variations in precipitation and temperature across the region stem from the influe...South America’s climatic diversity is a product of its vast geographical expanse, encompassing tropical to subtropical latitudes. The variations in precipitation and temperature across the region stem from the influence of distinct atmospheric systems. While some studies have characterized the prevailing systems over South America, they often lacked the utilization of statistical techniques for homogenization. On the other hand, other research has employed multivariate statistical methods to identify homogeneous regions regarding temperature and precipitation, but their focus has been limited to specific areas, such as the south, southeast, and northeast. Surprisingly, there is a lack of work that compares various multivariate statistical techniques to determine homogeneous regions across the entirety of South America concerning temperature and precipitation. This paper aims to address this gap by comparing three such techniques: Cluster Analysis (K-means and Ward) and Self Organizing Maps, using data from different sources for temperature (ERA5, ERA5-Land, and CRU) and precipitation (ERA5, ERA5-Land, and CPC). Spatial patterns and time series were generated for each region over the period 1981-2010. The results from this analysis of spatially homogeneous regions concerning temperature and precipitation have the potential to significantly benefit climate analysis and forecasts. Moreover, they can offer valuable insights for various climatological studies, guiding decision-making processes in diverse fields that rely on climate information, such as agriculture, disaster management, and water resources planning.展开更多
Hepatitis B virus(HBV)infection is the leading cause of severe chronic liver disease.This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes...Hepatitis B virus(HBV)infection is the leading cause of severe chronic liver disease.This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes in Latin America.Three levels of evolutionary adaptation may correlate with the clinical outcomes of HBV infection.Infections in Latin America are predominantly of genotype H in Mexico and genotype F in Central and South America;these strains have historically circulated among the indigenous population.Both genotypes appear to be linked to a benign course of disease among the native and mestizo Mexicans and native South Americans.In contrast,genotypes F,A and D are common in acute and chronic infections among mestizos with Caucasian ancestry.Hepatocellular carcinoma is rare in Mexicans,but it has been associated with genotype F1b among Argentineans.This observation illustrates the significance of ascertaining the genetic and environmental factors involved in the development of HBV-related liver disease in Latin America,which contrast with those reported in other regions of the world.展开更多
A large-scale wave of mass protests broke out in fifteen Latin American countries during 2019.Some protests led to the resignation of the president and the collapse of the government.Others caused social unrest and bl...A large-scale wave of mass protests broke out in fifteen Latin American countries during 2019.Some protests led to the resignation of the president and the collapse of the government.Others caused social unrest and bloody conflicts.Some protests led to a national"curfew",and the government was forced to cancel major international conferences.For a time,over ten countries were engaged in turbulent and chaotic activities.Accordingly,the 2019 Latin American protests were also dubbed"Latin America’s Turmoil"by the international media.The scale,scope and impact of the protests have been rarely seen over the last forty years.They constituted part of the global chaos of 2019.The cause was not only the anxious response of the Latin American countries facing global changes not seen for a century,but also a concentrated outbreak of political,economic and social contradictions that has been accumulating in certain Latin American countries over a long period of time.Facing unprecedented global change over a century,the Latin American countries will be able to usher in the"Latin American Spring"only if they carry out profound reform with great courage,and achieve significant progress in their political systems,economic structures,and social security systems.展开更多
Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in e...Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in eastern North America, were selected to explore relationship between the northward distribution of temperate tree species and climatic factors. For each species, more than 30 sites at their north limits of distribution were obtained from their distribution maps, and 11 climatic indices at the north limits were computed. The standardized standard deviation (SD) method, which compares the magnitude of variance of climatic indices, was used to detect which climatic parameter was the most important for explaining northward distribution of these species. We presume that the climatic parameter that has the smallest variance at the north limit would be assigned as the dominant climatic factor for limiting the distribution of this species. The results derived from the standardized SD method indicated that the SD value of warmth index (WI) and/or annual biotemperature (ABT) were the smallest among the 11 climatic indices. Since both WI and ABT represent growing season temperature, it suggested that growing season temperature was the most important climatic factor for explaining the northward distribution of these temperate tree species. The relationships between several climatic indices, WI, coldness index (CI), annual precipitation (AP), annual range of temperature (ART) and humid/arid index were also analyzed. As a result, at the north limits of all these species, both WI and CI decreased with an increase of AP, and CI increased with an increase of ART. Besides growing season temperature, precipitation and climatic continentality also have influence on the northward distribution of the temperate trees in eastern North America.展开更多
Through the introduction of the American poem "I Hear America Singing" and its writer Walt Whitman, the Chinese poem " 春望 "and its writer:杜甫, and the comparison of these two poems in prosody, l...Through the introduction of the American poem "I Hear America Singing" and its writer Walt Whitman, the Chinese poem " 春望 "and its writer:杜甫, and the comparison of these two poems in prosody, language, contents and emotion, writing techniques, political views field, etc, this essay analyses further some poetic phenomenon, and also draws a vivid picture of America in 19 century and China in 8 century.展开更多
The pandemic’s huge impact on all countries and regions is the biggest black swan event in 2020 and the biggest gray rhino event in 2021.Though Latin America was the last continent attacked by COVID-19,it became in 2...The pandemic’s huge impact on all countries and regions is the biggest black swan event in 2020 and the biggest gray rhino event in 2021.Though Latin America was the last continent attacked by COVID-19,it became in 2020 the designated epicenter of infection,surpassing Europe and catching up with the United States.The rapidity of spread in Latin America,the wide range and high incidence of infections,and the death toll were larger than in other places.The pandemic has resulted in the largest economic recession in Latin American history.It also has a significant impact on China-Latin America relations.When the pandemic in Latin American will end depends on large-scale,wide application of vaccines,strict prevention and control,and international cooperation.丁he pandemic reveals the fierce contradiction between society and nature.展开更多
This paper studies post-war America around the 1950's when On the Road was written and analyzes the protagonist Dean Moriarty as a spokesman of the Beat Generation.He is a typical beat who revolts against the trad...This paper studies post-war America around the 1950's when On the Road was written and analyzes the protagonist Dean Moriarty as a spokesman of the Beat Generation.He is a typical beat who revolts against the traditional social values and chases after the spiritual complacency.In addition,he opposes wars and advocates the equality between men and women.Thus in a sense Dean is a rebellious hero and stands ahead of his age.展开更多
This paper aims to review and analyze the literature on the expansion of Chinese firms to Latin America. In order to achieve this objective, it first reviews the literature on the internationalization of Chinese MNCs,...This paper aims to review and analyze the literature on the expansion of Chinese firms to Latin America. In order to achieve this objective, it first reviews the literature on the internationalization of Chinese MNCs, the theoretical frameworks discussed in the literature and the principal features of companies from China. Second, it describes the economic and political relations between the countries, specifically the threats and opportunities for Latin America and the trade and investment trends. The review shows that the majority of the current literature on Chinese MNCs has a focus on their expansion to developed countries, on the conceptual framework needed to understand this expansion, and on the competition for foreign investments from developed countries. As a result, the analysis makes evident that research gaps seem to exist in the following areas: (1) the relative value of Chinese companies' existing advantages, (2) the sustainability of these advantages once the lead, probably given by OEMs or JVs, had been exhausted, (3) research works based on quantitative and comparative data, (4) the motives for FDI, (5) the entry mode, configuration, control and strategy of Chinese companies investing in Latin America, and (6) the potential opportunities presented to European companies operating in Latin America.展开更多
基于《地理学报》和Annals of the Association of American Geographers学术论文的统计,对比近百年中美两国地理学的发展脉络,着重从总体特征、重点研究内容及其变化、理论—实践关系三方面对比异同,获得经验和借鉴。美国地理学经过初...基于《地理学报》和Annals of the Association of American Geographers学术论文的统计,对比近百年中美两国地理学的发展脉络,着重从总体特征、重点研究内容及其变化、理论—实践关系三方面对比异同,获得经验和借鉴。美国地理学经过初期发展、高速发展后,目前进入持续发展阶段;中国地理学在曲折中崛起,目前正处在高速发展时期。美国地理学中人文地理学一直居主导地位,中国则从重视自然地理开始逐渐向自然、人文、方法三足鼎立方向迈进;美国地理学家非常重视微观、中观实践,但在国家宏观决策中远没有中国地理学家发挥作用更直接。美国地理学研究水平高于中国,但这种差距正在缩小,研究方向的变化相差3~5年。世界地理研究中心有向亚太地区、向中国转移的可能,中国地理学家要勇于创建具有中国特色的地理学派。展开更多
Latin America shows one of the highest incidence rates of gastric cancer in the world,with variations in mortality rates among nations or even within countries belonging to this region.Gastric cancer is the result of ...Latin America shows one of the highest incidence rates of gastric cancer in the world,with variations in mortality rates among nations or even within countries belonging to this region.Gastric cancer is the result of a multifactorial complex process,for which a multistep model of carcinogenesis is currently accepted.Additionally to the infection with Helicobacter pylori,that plays a major role,environmental factors as well as genetic susceptibility factors are significant players at different stages in the gastric cancer process.The differences in population origin,demographic structure,socio-economic development,and the impact of globalization lifestyles experienced in Latin America in the last decades,all together offer opportunities for studying in this context the influence of genetic polymorphisms in the susceptibility to gastric cancer.The aim of this article is to discuss current trends on gastric cancer in Latin American countries and to review the available published information about studies of association of gene polymorphisms involved in gastric cancer susceptibility from this region of the world.A total of 40 genes or genomic regions and69 genetic variants,58%representing markers involved in inflammatory response,have been used in a number of studies in which predominates a low number of individuals(cases and controls)included.Polymorphisms of IL-1B(-511 C/T,14 studies;-31 T/C,10 studies)and IL-1RN(variable number of tandem repeats,17 studies)are the most represented ones in the reviewed studies.Other genetic variants recently evaluated in large metaanalyses and associated with gastric cancer risk were also analyzed in a few studies[e.g.,prostate stem cell antigen(PSCA),CDH1,Survivin].Further and better analysis centered in gene polymorphisms linked to other covariates,epidemiological studies and the information provided by meta-analyses and genome-wide association studies should help to improve our understanding of gastric cancer etiology in order to develop appropriate health programs in Latin America.展开更多
BACKGROUND The worldwide epidemiology of inflammatory bowel disease(IBD)is rapidly changing.Increasing Crohn’s disease(CD)and ulcerative colitis(UC)incidence and prevalence have been recorded in developing regions su...BACKGROUND The worldwide epidemiology of inflammatory bowel disease(IBD)is rapidly changing.Increasing Crohn’s disease(CD)and ulcerative colitis(UC)incidence and prevalence have been recorded in developing regions such as Asia,Africa and Eastern Europe where it was previously thought to be uncommon.Whether this is also the case in South America is not well known.Demonstration that developing regions worldwide have increasing IBD incidence would indicate that environmental change plays a significant role in the development of IBD.AIM To report the incidence,prevalence and disease characteristics of CD and UC within the South American continent.METHODS A systematic review was conducted by searching published studies in major international and regional databases(MEDLINE,EMBASE and Scopus)between January 1990 and December 2018.Outcomes considered were incidence,prevalence,phenotype,environmental and genetic factors,ethnicity and gender.A pair of independent reviewers screened and reviewed all identified articles.RESULTS One hundred and sixty two citations were initially retrieved with 18 studies included in this systematic review.The majority of included studies were from Brazil(n=13,72%).The incidence of UC ranged from 4.3-5.3/100000 personyears whilst the incidence of CD ranged from 0.74-3.5/100000 person-years.Prevalence ranged from 15.0-24.1/100000 inhabitants for UC and from 2.4-14.1/100000 inhabitants for CD.The incidence and prevalence of both UC and CD has increased significantly in Brazil over the past 21 years.Pancolitis was the most common disease distribution in patients with UC whilst colonic involvement was the most common distribution in CD.People residing in urban areas were at higher risk of developing both CD and UC.CONCLUSION The IBD burden in South America is increasing at a rate possibly even greater than other developing regions around the world.There is a paucity of highquality epidemiological studies and further robust and representative data are required to further explore modifiable risk factors and disease phenotypes.展开更多
Latin America, a region with a population greater than 600000000 individuals, is well known due to its wide geographic, socio-cultural and economic heterogeneity. Access to health care remains as the main barrier that...Latin America, a region with a population greater than 600000000 individuals, is well known due to its wide geographic, socio-cultural and economic heterogeneity. Access to health care remains as the main barrier that challenges routine screening, early diagnosis and proper treatment of hepatocellular carcinoma(HCC). Therefore, identification of population at risk, implementation of surveillance programs and access to curative treatments has been poorly obtained in the region. Different retrospective cohort studies from the region have shown flaws in the implementation process of routine surveillance and early HCC diagnosis. Furthermore, adherence to clinical practice guidelines recommendations assessed in two studies from Brazil and Argentina demonstrated that there is also room for improvement in this field, similarly than the one observed in Europe and the United States. In summary, Latin America shares difficulties in HCC decision-making processes similar to those from developed countries. However, a transversal limitation in the region is the poor access to health care with the consequent limitation to standard treatments for overall population. Specifically, universal health care access to the different World Health Organization levels is crucial, including improvement in research, education and continuous medical training in order to expand knowledge and generation of data promoting a continuous improvement in the care of HCC patients.展开更多
文摘BACKGROUND A progressive decrease in exclusive breastfeeding(BF)is observed in Latin America and the Caribbean compared with global results.The possibility of being breastfed and continuing BF for>6 months is lower in low birth weight than in healthy-weight infants.AIM To identify factors associated with BF maintenance and promotion,with particular attention to low-and middle-income countries,by studying geographic,socioeconomic,and individual or neonatal health factors.METHODS A scoping review was conducted in 2018 using the conceptual model of social determinants of health published by the Commission on Equity and Health Inequalities in the United States.The extracted data with common characteristics were synthesized and categorized into two main themes:(1)Sociodemographic factors and proximal determinants involved in the initiation and maintenance of BF in low-birth-weight term infants in Latin America;and(2)individual characteristics related to the self-efficacy capacity for BF maintenance and adherence in low-birth-weight term infants.RESULTS This study identified maternal age,educational level,maternal economic capacity,social stratum,exposure to BF substitutes,access to BF information,and quality of health services as mediators for maintaining BF.CONCLUSION Individual self-efficacy factors that enable BF adherence in at-risk populations should be analyzed for better health outcomes.
基金funded by ANID—Millennium Science Initiative Program (No. NCS2022_053)。
文摘Traditional Chinese medicine(TCM) arrived from China to Latin America and the Caribbean in the 1840s due to the massive migration of Chinese people to the region. In a few years, the press noticed the presence of Chinese herbalists practicing in different cities and countries regardless of the demographic weight of the Chinese community. The fascination with Chinese doctors implicated not only the press but also the literature, a phenomenon particularly observed in Cuba. In the first decades of the 20th century, the reactivation of Chinese immigration to the region fostered an anti-Chinese climate that materialized in more significant migratory restrictions and control of their businesses, such as what happened with Chinese herbalists. These herbalists who practiced inside and outside the Chinese community started to object to criticism and persecution by the conservative press and professional doctors. Despite this, Chinese doctors will continue to maintain their support of a significant number of ill persons. This work seeks to illuminate the historical relevance of TCM in Latin America and the Caribbean, focusing on the cases of Peru, Chile, and Cuba. This last country was far from China culturally and geographically, but as in many other small towns in the region, Chinese medicine presented an alternative to the treatment of illnesses.
基金supported by the National Natural Science Foundation of China(31870664)the 948 Program of National Forestry and Grassland Administration(2013-4-47)the National Key Research and Development Program of China(2022YFD2200103)。
文摘The genus Thuja is ideal for investigating the genetic basis of the East Asia-North America disjunction.The biogeographical background of the genus is debatable and an adaptive strategy is lacking.Through the analysis and mining of comparative transcriptomes,species differentiation and positively selected genes(PSGs)were identified to provide information for understanding the environmental adaptation strategies of the genus Thuja.De novo assembly yielded 44,397-74,252 unigenes of the five Thuja species with contig N50length ranging from 1,559 to 1,724 bp.Annotations revealed a similar distribution of functional categories among them.Based on the phylogenetic trees constructed using the transcriptome data,T.sutchuenensis was divided first,followed by T.plicata and T.occidentalis.The final differentiation of T.koraiensis and T.standishii formed a clade.Enrichment analysis indicated that the PSGs of the North American Thuja species were involved in plant hormone signal transduction and carbon fixation of photosynthetic organisms pathways.The PSGs of East Asian Thuja were related to phenolic,alkaloid,and terpenoid synthesis,important stress-resistant genes and could increase plant resistance to external environmental stresses.This study discovered numerous aroma synthetic-related PSGs including terpene synthase(TPS)genes and lipid phosphate phosphatase 2(LPP2),associated with the synthetic aroma of T.sutchuenensis.Physiological indicators,such as the contents of soluble sugars,total chlorophyll,total phenolics,and total flavonoids were determined,which are consistent with the PSGs enrichment pathways associated with adaptive strategies in the five Thuja species.The results of this study provide an important basis for future studies on conservation genetics.
基金This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil(CAPES)-Finance Code 001.
文摘Clear and data-driven bioregionalizations can provide a framework to test hypotheses and base biodiversity conservation.Here we used occurrence and abundance data in combination with objective analytical methods to propose two bioregionalization schemes for tree species of the Cerrado and the Pantanal in South America.We also evaluated the contribution of three sets of determinants of the occurrence-and abundance-based subregions.We compiled data on tree species composition from 894 local assemblages based on species occurrences,and from 658 local assemblages based on species abundances.We used an unconstrained community-level modelling approach and clustering techniques to identify and map tree subregions for the occurrence and the abundance data sets,separately.Hierarchical clustering analyses were conducted to investigate floristic affinities between the subregions and to map broader floristic regions.We used multinomial logistic regression models,deviance partitioning,and rank-sum tests to assess the main subregion correlates.We identified 18 occurrence-and four abundance-based subregions in the Cerrado-Pantanal.The hierarchical classifications grouped the occurrence-based subregions into nine floristic zones and abundance-based subregions into two broad floristic zones.Variation in subregions were explained mainly by environmental factors and spatial structure in both occurrence and abundance data sets.The occurrence-and abundance-based subregions are complementary approaches to disentangle macroecological patterns and to plan conservation efforts in the Cerrado and the Pantanal.Our findings based on occurrence data revealed more complex and interdigitated boundaries between subregions of tree species than previously reported.The environment,historical stability,and human effects act in a synergetic way on the distribution of the subregions.Finally,the relevance of contemporary environmental factors to the subregion patterns we found alert us to the profound impact global warming may have on the spatial organization of the Cerrado-Pantanal tree flora.
文摘Understanding the mechanisms underlying plant responses to climate change is an important step toward developing effective mitigation strategies. Polyploidy is an important evolutionary trait that can influence the capacity of plants to adapt to climate change. The environmental flexibility of polyploids suggests their resiliency to climate change, however, such hypotheses have not yet received empirical evidence. To understand how ploidy level may influence response to climate change, we modeled the current and future distribution of 54 Crataegus species under moderate to severe environments and compared the range change between diploids and polyploids. The majority of studied species are predicted to experience considerable range expansion. We found a negative interaction between ploidy and ecoregions in determining the response to climate change. In extreme environments, polyploids are projected to experience a higher range expansion than diploids with climate change, while the opposite is true for moderate environments. The range expansion of Crataegus species can be attributed to their tolerance for a wide range of environmental conditions. Despite the higher tolerance of polyploids to extreme environments, they do not necessarily outperform diploids in moderate environments, which can be attributed to the varying nature of species interactions along a stress gradient.
文摘President Xi Jinping’s America trip from November 14 to 17,including his talks with U.S.President Joe Biden and his attendance at the 30th APEC Economic Leaders’Meeting in San Francisco,is widely believed to have added stability to China-U.S.relations,brought new impetus to Asia-Pacific cooperation and injected positive energy into the international and regional landscape.
文摘South America’s climatic diversity is a product of its vast geographical expanse, encompassing tropical to subtropical latitudes. The variations in precipitation and temperature across the region stem from the influence of distinct atmospheric systems. While some studies have characterized the prevailing systems over South America, they often lacked the utilization of statistical techniques for homogenization. On the other hand, other research has employed multivariate statistical methods to identify homogeneous regions regarding temperature and precipitation, but their focus has been limited to specific areas, such as the south, southeast, and northeast. Surprisingly, there is a lack of work that compares various multivariate statistical techniques to determine homogeneous regions across the entirety of South America concerning temperature and precipitation. This paper aims to address this gap by comparing three such techniques: Cluster Analysis (K-means and Ward) and Self Organizing Maps, using data from different sources for temperature (ERA5, ERA5-Land, and CRU) and precipitation (ERA5, ERA5-Land, and CPC). Spatial patterns and time series were generated for each region over the period 1981-2010. The results from this analysis of spatially homogeneous regions concerning temperature and precipitation have the potential to significantly benefit climate analysis and forecasts. Moreover, they can offer valuable insights for various climatological studies, guiding decision-making processes in diverse fields that rely on climate information, such as agriculture, disaster management, and water resources planning.
基金Supported by The National Council of Science and Technology,Fondo Sectorial Salud-2010-1-139085the Jalisco State Council of Science and Technology,COECYTJAL-Universidad de Guadalajara 5-2010-1-1041 to Roman S,Guadalajara,Jalisco,Mexico
文摘Hepatitis B virus(HBV)infection is the leading cause of severe chronic liver disease.This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes in Latin America.Three levels of evolutionary adaptation may correlate with the clinical outcomes of HBV infection.Infections in Latin America are predominantly of genotype H in Mexico and genotype F in Central and South America;these strains have historically circulated among the indigenous population.Both genotypes appear to be linked to a benign course of disease among the native and mestizo Mexicans and native South Americans.In contrast,genotypes F,A and D are common in acute and chronic infections among mestizos with Caucasian ancestry.Hepatocellular carcinoma is rare in Mexicans,but it has been associated with genotype F1b among Argentineans.This observation illustrates the significance of ascertaining the genetic and environmental factors involved in the development of HBV-related liver disease in Latin America,which contrast with those reported in other regions of the world.
文摘A large-scale wave of mass protests broke out in fifteen Latin American countries during 2019.Some protests led to the resignation of the president and the collapse of the government.Others caused social unrest and bloody conflicts.Some protests led to a national"curfew",and the government was forced to cancel major international conferences.For a time,over ten countries were engaged in turbulent and chaotic activities.Accordingly,the 2019 Latin American protests were also dubbed"Latin America’s Turmoil"by the international media.The scale,scope and impact of the protests have been rarely seen over the last forty years.They constituted part of the global chaos of 2019.The cause was not only the anxious response of the Latin American countries facing global changes not seen for a century,but also a concentrated outbreak of political,economic and social contradictions that has been accumulating in certain Latin American countries over a long period of time.Facing unprecedented global change over a century,the Latin American countries will be able to usher in the"Latin American Spring"only if they carry out profound reform with great courage,and achieve significant progress in their political systems,economic structures,and social security systems.
文摘Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in eastern North America, were selected to explore relationship between the northward distribution of temperate tree species and climatic factors. For each species, more than 30 sites at their north limits of distribution were obtained from their distribution maps, and 11 climatic indices at the north limits were computed. The standardized standard deviation (SD) method, which compares the magnitude of variance of climatic indices, was used to detect which climatic parameter was the most important for explaining northward distribution of these species. We presume that the climatic parameter that has the smallest variance at the north limit would be assigned as the dominant climatic factor for limiting the distribution of this species. The results derived from the standardized SD method indicated that the SD value of warmth index (WI) and/or annual biotemperature (ABT) were the smallest among the 11 climatic indices. Since both WI and ABT represent growing season temperature, it suggested that growing season temperature was the most important climatic factor for explaining the northward distribution of these temperate tree species. The relationships between several climatic indices, WI, coldness index (CI), annual precipitation (AP), annual range of temperature (ART) and humid/arid index were also analyzed. As a result, at the north limits of all these species, both WI and CI decreased with an increase of AP, and CI increased with an increase of ART. Besides growing season temperature, precipitation and climatic continentality also have influence on the northward distribution of the temperate trees in eastern North America.
文摘Through the introduction of the American poem "I Hear America Singing" and its writer Walt Whitman, the Chinese poem " 春望 "and its writer:杜甫, and the comparison of these two poems in prosody, language, contents and emotion, writing techniques, political views field, etc, this essay analyses further some poetic phenomenon, and also draws a vivid picture of America in 19 century and China in 8 century.
文摘The pandemic’s huge impact on all countries and regions is the biggest black swan event in 2020 and the biggest gray rhino event in 2021.Though Latin America was the last continent attacked by COVID-19,it became in 2020 the designated epicenter of infection,surpassing Europe and catching up with the United States.The rapidity of spread in Latin America,the wide range and high incidence of infections,and the death toll were larger than in other places.The pandemic has resulted in the largest economic recession in Latin American history.It also has a significant impact on China-Latin America relations.When the pandemic in Latin American will end depends on large-scale,wide application of vaccines,strict prevention and control,and international cooperation.丁he pandemic reveals the fierce contradiction between society and nature.
文摘This paper studies post-war America around the 1950's when On the Road was written and analyzes the protagonist Dean Moriarty as a spokesman of the Beat Generation.He is a typical beat who revolts against the traditional social values and chases after the spiritual complacency.In addition,he opposes wars and advocates the equality between men and women.Thus in a sense Dean is a rebellious hero and stands ahead of his age.
文摘This paper aims to review and analyze the literature on the expansion of Chinese firms to Latin America. In order to achieve this objective, it first reviews the literature on the internationalization of Chinese MNCs, the theoretical frameworks discussed in the literature and the principal features of companies from China. Second, it describes the economic and political relations between the countries, specifically the threats and opportunities for Latin America and the trade and investment trends. The review shows that the majority of the current literature on Chinese MNCs has a focus on their expansion to developed countries, on the conceptual framework needed to understand this expansion, and on the competition for foreign investments from developed countries. As a result, the analysis makes evident that research gaps seem to exist in the following areas: (1) the relative value of Chinese companies' existing advantages, (2) the sustainability of these advantages once the lead, probably given by OEMs or JVs, had been exhausted, (3) research works based on quantitative and comparative data, (4) the motives for FDI, (5) the entry mode, configuration, control and strategy of Chinese companies investing in Latin America, and (6) the potential opportunities presented to European companies operating in Latin America.
文摘基于《地理学报》和Annals of the Association of American Geographers学术论文的统计,对比近百年中美两国地理学的发展脉络,着重从总体特征、重点研究内容及其变化、理论—实践关系三方面对比异同,获得经验和借鉴。美国地理学经过初期发展、高速发展后,目前进入持续发展阶段;中国地理学在曲折中崛起,目前正处在高速发展时期。美国地理学中人文地理学一直居主导地位,中国则从重视自然地理开始逐渐向自然、人文、方法三足鼎立方向迈进;美国地理学家非常重视微观、中观实践,但在国家宏观决策中远没有中国地理学家发挥作用更直接。美国地理学研究水平高于中国,但这种差距正在缩小,研究方向的变化相差3~5年。世界地理研究中心有向亚太地区、向中国转移的可能,中国地理学家要勇于创建具有中国特色的地理学派。
文摘Latin America shows one of the highest incidence rates of gastric cancer in the world,with variations in mortality rates among nations or even within countries belonging to this region.Gastric cancer is the result of a multifactorial complex process,for which a multistep model of carcinogenesis is currently accepted.Additionally to the infection with Helicobacter pylori,that plays a major role,environmental factors as well as genetic susceptibility factors are significant players at different stages in the gastric cancer process.The differences in population origin,demographic structure,socio-economic development,and the impact of globalization lifestyles experienced in Latin America in the last decades,all together offer opportunities for studying in this context the influence of genetic polymorphisms in the susceptibility to gastric cancer.The aim of this article is to discuss current trends on gastric cancer in Latin American countries and to review the available published information about studies of association of gene polymorphisms involved in gastric cancer susceptibility from this region of the world.A total of 40 genes or genomic regions and69 genetic variants,58%representing markers involved in inflammatory response,have been used in a number of studies in which predominates a low number of individuals(cases and controls)included.Polymorphisms of IL-1B(-511 C/T,14 studies;-31 T/C,10 studies)and IL-1RN(variable number of tandem repeats,17 studies)are the most represented ones in the reviewed studies.Other genetic variants recently evaluated in large metaanalyses and associated with gastric cancer risk were also analyzed in a few studies[e.g.,prostate stem cell antigen(PSCA),CDH1,Survivin].Further and better analysis centered in gene polymorphisms linked to other covariates,epidemiological studies and the information provided by meta-analyses and genome-wide association studies should help to improve our understanding of gastric cancer etiology in order to develop appropriate health programs in Latin America.
文摘BACKGROUND The worldwide epidemiology of inflammatory bowel disease(IBD)is rapidly changing.Increasing Crohn’s disease(CD)and ulcerative colitis(UC)incidence and prevalence have been recorded in developing regions such as Asia,Africa and Eastern Europe where it was previously thought to be uncommon.Whether this is also the case in South America is not well known.Demonstration that developing regions worldwide have increasing IBD incidence would indicate that environmental change plays a significant role in the development of IBD.AIM To report the incidence,prevalence and disease characteristics of CD and UC within the South American continent.METHODS A systematic review was conducted by searching published studies in major international and regional databases(MEDLINE,EMBASE and Scopus)between January 1990 and December 2018.Outcomes considered were incidence,prevalence,phenotype,environmental and genetic factors,ethnicity and gender.A pair of independent reviewers screened and reviewed all identified articles.RESULTS One hundred and sixty two citations were initially retrieved with 18 studies included in this systematic review.The majority of included studies were from Brazil(n=13,72%).The incidence of UC ranged from 4.3-5.3/100000 personyears whilst the incidence of CD ranged from 0.74-3.5/100000 person-years.Prevalence ranged from 15.0-24.1/100000 inhabitants for UC and from 2.4-14.1/100000 inhabitants for CD.The incidence and prevalence of both UC and CD has increased significantly in Brazil over the past 21 years.Pancolitis was the most common disease distribution in patients with UC whilst colonic involvement was the most common distribution in CD.People residing in urban areas were at higher risk of developing both CD and UC.CONCLUSION The IBD burden in South America is increasing at a rate possibly even greater than other developing regions around the world.There is a paucity of highquality epidemiological studies and further robust and representative data are required to further explore modifiable risk factors and disease phenotypes.
文摘Latin America, a region with a population greater than 600000000 individuals, is well known due to its wide geographic, socio-cultural and economic heterogeneity. Access to health care remains as the main barrier that challenges routine screening, early diagnosis and proper treatment of hepatocellular carcinoma(HCC). Therefore, identification of population at risk, implementation of surveillance programs and access to curative treatments has been poorly obtained in the region. Different retrospective cohort studies from the region have shown flaws in the implementation process of routine surveillance and early HCC diagnosis. Furthermore, adherence to clinical practice guidelines recommendations assessed in two studies from Brazil and Argentina demonstrated that there is also room for improvement in this field, similarly than the one observed in Europe and the United States. In summary, Latin America shares difficulties in HCC decision-making processes similar to those from developed countries. However, a transversal limitation in the region is the poor access to health care with the consequent limitation to standard treatments for overall population. Specifically, universal health care access to the different World Health Organization levels is crucial, including improvement in research, education and continuous medical training in order to expand knowledge and generation of data promoting a continuous improvement in the care of HCC patients.