Two-tiered reconstruction of Late Pleistocene to Holocene changes in the freezing level height in the largest glacierized areas of the Colombian Andes

One way of deducing vertical shifts in the altitudinal distribution of Colombian high-altitude páramo environments is by inferring fluctuations in the height of the local freezing level.In our research,we are implementing two complementary approaches to reconstruct Late Pleistocene to Holocene changes in the freezing level height(FLH)in two of the most extensively glacier-covered areas of the northern Andes.We combined remote sensing and field-based geomorphological mapping with time-series reconstruction of changes in the altitude of the 0°C isotherm.Changes in the FLH were based on alreadypublished~30 kyr paleo-reconstructions of sea surface temperatures(SSTs)of the eastern tropical Pacific and the western tropical Atlantic,as well as on reconstructed long-term sea level changes and empirical orthogonal functions of present-day(historical)Indo-Pacific and tropical Atlantic SST anomalies.We also analyzed the probability distribution of air-sea temperature differences and the spatial distribution of grid points with SSTs above the minimum threshold necessary to initiate deep convection.We considered available historical nearsurface and free air temperature data of ERA-Interim reanalysis products,General Circulation Model(GCM)simulations,weather stations,and(deployed by our group)digital sensors,to assess the normal Environmental Lapse Rates(ELRs)at the regional to local scale.The combined maps of glacial landforms and our reconstructed FLHs provided us with a wellfounded inference of potential past glacier advances,narrowing down the coarse resolution of ice margins suggested by previous research efforts.The extent of the areas with temperatures below the freezing point suggested here for the summits of our main study site exceeds in magnitude the corresponding glacier icecaps and front advances proposed by previous studies.Conversely,our average lowest altitudes of the FLH for our comparative site are consistently above the main glacier-front advances previously suggested.Our results indicate that,compared to the maximum upward changes that likely took place over the past ca.20,000 years in our two areas of interest,the observed(present-day)upward shifts of the FLH have occurred at a rate that significantly surpasses our inferred rates.Our study helps fill the gaps in understanding past climatic changes and present trends in the region of interest and provides some insights into analyzing the signals of natural and anthropogenic climate change.

Changes in Mangrove Epifaunal Assemblages Caused by Forest Logging during Hunting of the Neotropical Cormorant (<i>Phalacrocorax brasilianus</i>) on the Colombian Pacific Coast

Although the importance of mangroves is clearly recognized around the world, these ecosystems are being strongly altered by the logging of their forests for multiple purposes. The Colombian Pacific coast is not an exception to this situation, and apart from the traditional logging of wood, the hunting of the Neotropical Cormorant or Pato-cuervo (Phalacrocorax brasilianus), an activity largely unknown but widespread in the region, is also causing the logging of great extensions of mangroves. The aim of this research was to determine if the assemblages of mollusks and crustaceans of these mangroves are being affected by the hunting of the cormorant. To answer this question, quantitative samplings were realized in four transects in logged and unlogged mangrove areas on the southwestern coast of the Colombian Pacific and diversity, equitability and dominance of macrofaunal assemblages of mangroves were calculated. The data show that although significant differences between diversity indices were not found, there were important differences in equitability (total J’: 0.55 in T1, 0.77 in T2, 0.46 in T3 and 0.65 in T4), specific dominance, and composition of species (T1: 11 species, T2: 13, T3: 9 and T4: 11) between logged and unlogged areas. Based on these results, although forest structure and interstitial salinity were different among transects, we conclude that the present practice of exploitation of the Neotropical Cormorant is affecting the epifaunal populations of mangroves, causing changes in the composition and dominance of species.

A Semiotic Approach to Social Discourses on Colombian Political Events of the Late Twentieth Century

The paper that we present below addresses a methodological approach to Marc Angenot’s statements,in his Social Discourse(2012)of integrating certain views and opinions,taken from the written press,literature,and television,on events happened in Colombia,prior to 1990 presidential elections.When we study the discursivities1 that are the product and/or the representatives of some political crimes that took place in Colombia between August 1989 and April 1990,we speak mainly on discourses that took place some decades ago.Some of these stories have allowed us to give meaning to the world and,at the same time,integrate us in it.

Cold Seeps Associated with Structured Benthic Communities: More Accurate Identification and Evaluation Using a New Multibeam Survey Methodology in the Offshore Southern Colombian Caribbean

A new methodology was developed to identify cold seeps and structured benthic communities associated, which was applied for the first time in the offshore southern Colombian Caribbean. The integral method consists on a new processing of double-coverage (200%) high-resolution backscatter data combined with bathymetric information;validation was done correlating identified gas plumes, seabed cores and drift camera surveys. Results showed that the elimination of artefacts and the increased signal of the backscatter data allowed accurate plotting of seep boundaries and categorization of seeps into an activity catalogue, with more than 200 seeps identified. Most seeps have chemosynthetic communities associated and data analysis from a previous survey showed two ridges with hard ground as the only possible areas for the development the of deep- water corals. Seep results were compared with designated Areas of Significance for Biodiversity (ASB) identifying seeps both within and outside the ASBs, and showing that the presence of seeps and chemosynthetic communities associated were driven more by geological processes than for big-scale seabed morphology, since they were found in both plains and ridges. This methodology allows an accurate seabed map of structured benthic communities, which may work as a precise geo-hazard map to ensure the oil & gas industry can avoid these areas of shallow gas for further developments, and as a map of deep-water structured benthic communities with environmental significance.

Cockfighting Craze Lives on in Colombian Villages

文章真精彩！它把我们带到了南美洲西北部的哥伦比亚,在那里观赏了一次斗鸡竞赛。文章可读,原因有四: 描写精致:The referee rings a bell and the two angry birds erplode into thering,colliding(碰撞;抵触)recklessly(鲁莽地;不顾一切地)and exchangingmidair(半空中)kicks with the curved,razor-sharp spikes fastened to their legs。(三个动词可以玩味:explode/collide/exchange) 历史回顾:The stranger,said Don Pedro,tied his mule to a tree,and withoutsaying a word to the wide-eyed locals,challenged the foreman(领班;工头)of theUnited Fruit Company to a cockfight。 科学分析:The roosters fight for the hen。They can live together in peace but ifyou release a hen not a single one of them will remain alive。 冷静观察:At the pit,class divisions melt。Workers pit their roosters againstthose of landowners,greeting each other with handshakes before the fight。】

Vice President Xie Yuan Meets with Delegation of Colombian Governors

On Oce 11,Vice-President Xie Yuan met with the delegation headed by Mr.Amilkar Acosta,Executive President of Colombian National Federation of Departments.Xie welcomed Mr.Amilkar Acosta;Mr.Sigifredo Salazar,governor of Risaralda;and Mr.Nebio de Jesus Echeverry,governor of Guaviare.He briefly introduced the CPAFFC and reviewed the

洛南任家滩—荞麦山正长斑岩成因及其对古元古代晚期裂解的指示——岩石化学及锆石U-Pb年龄和Lu—Hf同位素特征

华北克拉通南缘的陕西洛南—河南豫西地区出露一系列形成于1.8~1.6 Ga的碱性岩,对这些碱性岩的研究有助于提高对华北克拉通南缘古元古代构造环境的认识。笔者等选取陕西省洛南县任家滩—荞麦山一带碱性侵入体进行系统的岩石学、LA-ICP-MS锆石U-Pb年代学、Lu—Hf同位素分析和岩石地球化学研究,讨论了其成因机制和构造背景。研究表明,任家滩—荞麦山岩体的主体岩性为正长斑岩,加权平均年龄为1689±20 Ma(MSWD=0.12),表明其侵位时代为古元古代。该岩体富碱(Na_(2)O+K_(2)O=7.95%~9.5%),高钾(K_(2)O=4.67%~8.51%);稀土元素总量较高(496.15×10^(-6)~650.16×10^(-6),平均543.06×10^(-6)),轻、重稀土元素分馏比较明显,轻稀土元素相对富集(LREE=454×10^(-6)~605×10^(-6)),重稀土元素亏损(HREE=39.3×10^(-6)~45.6×10^(-6)),具有弱负铕异常;K、Rb、Ba、Th富集,Nb、Ta、P、Ti亏损,并且具有明显的Sr负异常。εHf(t)值<0,TDM1值为2038~2218 Ma,TDM2值为2250~2516 Ma,说明岩浆源区物质与富集地幔有关或受到过地壳物质的混染。因此,任家滩—荞麦山岩体是由地幔玄武质岩浆与地壳基底太华杂岩形成的中酸性花岗质岩浆混合后形成的熔体,经强烈的结晶分异作用形成的,其形成于陆内裂谷的构造环境,是华北克拉通南缘对哥伦比亚超大陆裂解事件的响应。

Spatiotemporal assessment of particulate matter(PM_(10) and PM_(2.5)) and ozone in a Caribbean urban coastal city

Air pollution has become a critical issue in urban areas,so a broad understanding of its spatiotemporal characteristics is important to develop public policies.This study analyzes the spatiotemporal variation of atmospheric particulate matter(PM_(10) and PM_(2.5))and ozone(O_(3))in Barranquilla,Colombia from March 2018 to June 2019 in three monitoring stations.The average concentrations observed for the Móvil,Policía,and Tres Avemarías stations,respectively,for PM_(10):46.4,51.4,and 39.7μg/m^(3);for PM_(2.5):16.1,18.1,and 15.1μg/m^(3) and for O_(3):35.0,26.6,and 33.6μg/m^(3).The results indicated spatial and temporal variations between the stations and the pollutants evaluated.The highest PM concentrations were observed in the southern part of the city,while for ozone,higher concentrations were observed in the north.These variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study area.This study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla Salamanca Natural Park and long-range transport of dust particles from the Sahara Desert.This study provides a scientific baseline for understanding air quality in the city,which enables policy makers to adopt efficient measures that jointly prevent and control pollution.

Mining Threats to Ancient Anthropogenic Soils and other Resources Associated to Indigenous Food Security in the Middle Caqueta River, Colombia

Mining is encroaching upon Protected Areas and Indigenous Reserves in the Colombian Amazon. In the Middle Caqueta region small-scale, illegal gold mining is eroding riverbanks, affecting water quality, and jeopardizing the livelihoods of indigenous peoples. In addition, mining also threatens the integrity of pre-Columbian anthropogenic soils （terra preta） created between 500 years to 2,000 years B.P. on the bluffs of the Caqueta . River. These soils are the only, non-flooded fertile soils present in the region, and as such are important for local indigenous communities. In Colombia, there is little knowledge about Terra Preta soils. This work assesses the present and potential dangers artisanal mining has for terra preta soils and other natural resources that are central to indigenous peoples＇ food security. Results posit that more knowledge is needed about the way terra preta soils are related to the livelihoods of indigenous people so that informed policy decisions can be made about the desirability of mining in the region.

2015年美洲杯哥伦比亚队技战术分析

文章以哥伦比亚足球队在2015年美洲杯比赛中面对不同的对手所采取的各种不同首发阵型,以及不同阵型的优劣势分析,并结合SWOT分析和KPI分析结果,讨论了哥伦比亚队近期的打法特征。

云南峨山地区东川群黑山组流纹质碎斑熔岩锆石U-Pb年龄及其地质意义

滇中地区中元古界"昆阳群"、"东川群"的地层层序是长期争议的重大基础地质问题。本次在峨山地区东川群黑山组中发育的厚近5m厚的流纹质碎斑熔岩采集样品D0023一件,选出120余粒锆石,获得的锆石LA-ICP-MS U-Pb加权平均年龄为(1569. 2±4. 5) Ma。样品锆石的Th/U值均大于0. 5,具有清晰的振荡环带结构,均为岩浆成因的锆石,表明东川群黑山组形成于中元古代早期,属非造山相关的火山岩系,可能是哥伦比亚超大陆裂解作用在扬子陆块的响应,为东川群的地层时代和层序研究增添了新资料。

美国城市规划的历史沿革和未来发展趋势

本文简单介绍了美国城市规划学的历史沿革以及影响城市规划的重大历史事件。美国城市规划学从无到有,从简单到复杂,从以建筑设计为核心的自然规划学到包括自然和社会分析在内的综合规划学,从单纯的城市规划学变成城市与区域规划学,从一门描述性的学科演化为描述性和定量性兼具的学科。虽然美国的城市发展有近400年的历史,但其城市规划学的历史沿革仅有100多年的历史,其间重大历史事件不断发生,规划代表人物辈出。现在美国城市规划学一方面面临新的发展机遇,另一方面也存在许多严峻的挑战。

不同萃取温度哥伦比亚咖啡萃取液香气分析

以中深烘哥伦比亚咖啡豆为原料,采用热脱附联合气相色谱-质谱法,对比不同萃取温度下咖啡萃取液的挥发性成分的差异,通过峰面积定量探究其主要风味物质的变化规律。结果表明,三种萃取温度哥伦比亚咖啡萃取液的香气成分有93种,成分基本一致,含量有所不同。各香气成分峰面积总和由大到小为:中温(456.19亿)>高温(443.81亿)>低温(422.16亿)。香气化合物主要有呋喃类、吡嗪类、吡啶类、吡咯类、醛类、酮类、酚类、酸类、醇类、内酯类、酯类、含硫类等。随着萃取温度升高,含量先增后减的有:呋喃类、吡嗪类、吡啶类、醛类、含硫化合物;含量不断增加的有吡咯类、酚类、内酯类;含量不断减少的有酮类、醇类、酯类。经专业认证的咖啡品鉴师进行杯测,感官品评结果表明:低温萃取液果香明显,中温更显坚果香,高温呈浓黑可可香。

不同焙炒程度下哥伦比亚咖啡豆香气成分分析

哥伦比亚咖啡豆经过浅度焙炒、中度焙炒、深度焙炒3种方式处理,用热脱附法提取香气成分,进行GCMSD分析,并采用峰面积对比含量变化,研究不同焙炒程度对哥伦比亚咖啡豆香气成分的影响。经过分析后得到,浅度焙炒有89个化合物,中度焙炒有90个化合物,深度焙炒有92个化合物,主要成分有吡嗪类化合物、呋喃类化合物、吡咯类化合物、吡啶类化合物、嘧啶类化合物,还有大量的醛酮类、酚类、酯类、醇类化合物。三种焙炒程度下的咖啡豆,香气种类不同,含量不同。深度香气含量最多,整体香气浓郁焦苦,而中度次之,整体香气浓郁香醇,浅焙最少,整体香气淡薄。

为电影注入新的生命力——希罗·盖拉访谈

在本次采访中,哥伦比亚导演希罗·盖拉对自己的身份及与观众的关系进行了反思。通过对导演杰作《蛇之拥抱》的仔细分析,读者能够了解其作品的内核精神、美学取向和制作细节。