Journal articles on the topic 'South American continent'
To see the other types of publications on this topic, follow the link: South American continent.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'South American continent.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Brown, Matthew. "Cycling in South America, 1880-1920." Anuario Colombiano de Historia Social y de la Cultura 48, no. 1 (December 15, 2020): 287–325. http://dx.doi.org/10.15446/achsc.v48n1.91552.
Full textAbstract:
Historians have tended to ignore the South American experience of cycling. The continent’s diverse history of sports has been effaced by a popular and academic focus on soccer. The global history of cycling has therefore omitted South America from its analysis, perpetuating mistaken assumptions about the continent’s absence from technological and social innovation. This article analyses the sources located across the continent to demonstrate that cyclists raced, toured, and did acrobatics, often watched by thousands of spectators, attracting the attention of chroniclers and the media. The physical sensations of travelling through the environment on a pedal-powered machine were new and unexpected. With its focus on cycling as sport, recreation and mode of transport, this article inserts South America into the early global history of cycling.
2
Herrera, Michael B., Spiridoula Kraitsek, Jose A. Alcalde, Daniel Quiroz, Herman Revelo, Luz A. Alvarez, Millor F. Rosario, et al. "European and Asian contribution to the genetic diversity of mainland South American chickens." Royal Society Open Science 7, no. 2 (February 2020): 191558. http://dx.doi.org/10.1098/rsos.191558.
Full textAbstract:
Chickens ( Gallus gallus domesticus ) from the Americas have long been recognized as descendants of European chickens, transported by early Europeans since the fifteenth century. However, in recent years, a possible pre-Columbian introduction of chickens to South America by Polynesian seafarers has also been suggested. Here, we characterize the mitochondrial control region genetic diversity of modern chicken populations from South America and compare this to a worldwide dataset in order to investigate the potential maternal genetic origin of modern-day chicken populations in South America. The genetic analysis of newly generated chicken mitochondrial control region sequences from South America showed that the majority of chickens from the continent belong to mitochondrial haplogroup E. The rest belongs to haplogroups A, B and C, albeit at very low levels. Haplogroup D, a ubiquitous mitochondrial lineage in Island Southeast Asia and on Pacific Islands is not observed in continental South America. Modern-day mainland South American chickens are, therefore, closely allied with European and Asian chickens. Furthermore, we find high levels of genetic contributions from South Asian chickens to those in Europe and South America. Our findings demonstrate that modern-day genetic diversity of mainland South American chickens appear to have clear European and Asian contributions, and less so from Island Southeast Asia and the Pacific Islands. Furthermore, there is also some indication that South Asia has more genetic contribution to European chickens than any other Asian chicken populations.
3
Curcio, Ana. "President's Page: Resources and geophysical opportunities in South America." Leading Edge 41, no. 4 (April 2022): 228–29. http://dx.doi.org/10.1190/tle41040228.1.
Full textAbstract:
The southern region of the American continent, or South America, is home to significant oil and gas, mineral, and renewable energy resources (Figure 1). Additionally, most South American countries provide a modern legal framework and incentives for investment in clean energy.
4
KARA, Adem. "OTTOMAN ARMENIANS WHO MIGRATED SOUTH AMERICAN CONTINENT." Journal of Academic Social Science Studies Volume 5 Issue 5, no. 5 (2012): 171–83. http://dx.doi.org/10.9761/jasss_205.
Full text
5
Allen, Robert C., Tommy E. Murphy, and Eric B. Schneider. "The Colonial Origins of the Divergence in the Americas: A Labor Market Approach." Journal of Economic History 72, no. 4 (December 14, 2012): 863–94. http://dx.doi.org/10.1017/s0022050712000629.
Full textAbstract:
This article introduces the Americas in the Great Divergence debate by measuring real wages in various North and South American cities between colonization and independence, and comparing them to Europe and Asia. We find that for much of the period, North America was the most prosperous region of the world, while Latin America was much poorer. We then discuss a series of hypotheses that can explain these results, including migration, the demography of the American Indian populations, and the various labor systems implemented in the continent.
6
Surovell, Todd A., Sarah A. Allaun, Barbara A. Crass, Joseph A. M. Gingerich, Kelly E. Graf, Charles E. Holmes, Robert L. Kelly, et al. "Late date of human arrival to North America: Continental scale differences in stratigraphic integrity of pre-13,000 BP archaeological sites." PLOS ONE 17, no. 4 (April 20, 2022): e0264092. http://dx.doi.org/10.1371/journal.pone.0264092.
Full textAbstract:
By 13,000 BP human populations were present across North America, but the exact date of arrival to the continent, especially areas south of the continental ice sheets, remains unclear. Here we examine patterns in the stratigraphic integrity of early North American sites to gain insight into the timing of first colonization. We begin by modeling stratigraphic mixing of multicomponent archaeological sites to identify signatures of stratigraphic integrity in vertical artifact distributions. From those simulations, we develop a statistic we call the Apparent Stratigraphic Integrity Index (ASI), which we apply to pre- and post-13,000 BP archaeological sites north and south of the continental ice sheets. We find that multiple early Beringian sites dating between 13,000 and 14,200 BP show excellent stratigraphic integrity. Clear signs of discrete and minimally disturbed archaeological components do not appear south of the ice sheets until the Clovis period. These results provide support for a relatively late date of human arrival to the Americas.
7
Krawczak, Felipe S., Marcelo B. Labruna, Joy A. Hecht, Christopher D. Paddock, and Sandor E. Karpathy. "Genotypic Characterization of Rickettsia bellii Reveals Distinct Lineages in the United States and South America." BioMed Research International 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/8505483.
Full textAbstract:
The bacterium Rickettsia bellii belongs to a basal group of rickettsiae that diverged prior to the pathogenic spotted fever group and typhus group Rickettsia species. Despite a diverse representation of R. bellii across more than 25 species of hard and soft ticks in the American continent, phylogeographical relationships among strains of this basal group-Rickettsia species are unknown; the work described here explores these relationships. DNA was extracted from 30 R. bellii tick isolates: 15 from the United States, 14 from Brazil, and 1 from Argentina. A total of 2,269 aligned nucleotide sites of 3 protein coding genes (gltA, atpA, and coxA) and 2 intergenic regions (rpmE-tRNAfmet and RC1027-xthA2) were concatenated and subjected to phylogenetic analysis by Bayesian methods. Results showed a separation of almost all isolates between North and South Americas, suggesting that they have radiated within their respective continents. Phylogenetic positions of the 30 isolates could be a result of not only their geographical origin but also the tick hosts they have coevolved with. Whether R. bellii originated with ticks in North or South America remains obscure, as our analyses did not show evidence for greater genetic divergence of R. bellii in either continent.
8
Wisitrassameewong, Komsit, Myung Soo Park, Hyun Lee, Aniket Ghosh, Kanad Das, Bart Buyck, Brian P. Looney, et al. "Taxonomic revision of Russula subsection Amoeninae from South Korea." MycoKeys 75 (November 9, 2020): 1–29. http://dx.doi.org/10.3897/mycokeys.75.53673.
Full textAbstract:
Russula subsection Amoeninae is morphologically defined by a dry velvety pileus surface, a complete absence of cystidia with heteromorphous contents in all tissues, and spores without amyloid suprahilar spot. Thirty-four species within subsection Amoeninae have been published worldwide. Although most Russula species in South Korea have been assigned European or North American names, recent molecular studies have shown that Russula species from different continents are not conspecific. Therefore, the present study aims to: 1) define which species of Russula subsection Amoeninae occur on each continent using molecular phylogenetic analyses; 2) revise the taxonomy of Korean Amoeninae. The phylogenetic analyses using the internal transcribed spacer (ITS) and multilocus sequences showed that subsection Amoeninae is monophyletic within subgenus Heterophyllidiae section Heterophyllae. A total of 21 Russula subsection Amoeninae species were confirmed from Asia, Australia, Europe, North America, and Central America, and species from different continents formed separate clades. Three species were recognized from South Korea and were clearly separated from the European and North American species. These species are R. bella, also reported from Japan, a new species described herein, Russula orientipurpurea, and a new species undescribed due to insufficient material.
9
Pereira, Anieli Guirro, and Carlos G. Schrago. "Arrival and diversification of mabuyine skinks (Squamata: Scincidae) in the Neotropics based on a fossil-calibrated timetree." PeerJ 5 (April 18, 2017): e3194. http://dx.doi.org/10.7717/peerj.3194.
Full textAbstract:
BackgroundThe evolution of South American Mabuyinae skinks holds significant biogeographic interest because its sister lineage is distributed across the African continent and adjacent islands. Moreover, at least one insular species,Trachylepis atlantica, has independently reached the New World through transoceanic dispersal. To clarify the evolutionary history of both Neotropical lineages, this study aimed to infer an updated timescale using the largest species and gene sampling dataset ever assembled for this group. By extending the analysis to the Scincidae family, we could employ fossil information to estimate mabuyinae divergence times and carried out a formal statistical biogeography analysis. To unveil macroevolutionary patterns, we also inferred diversification rates for this lineage and evaluated whether the colonization of South American continent significantly altered the mode of Mabuyinae evolution.MethodsA time-calibrated phylogeny was inferred under the Bayesian framework employing fossil information. This timetree was used to (i) evaluate the historical biogeography of mabuiyines using the statistical approach implemented in BioGeoBEARS; (ii) estimate macroevolutionary diversification rates of the South American Mabuyinae lineages and the patterns of evolution of selected traits, namely, the mode of reproduction, body mass and snout–vent length; (iii) test the hypothesis of differential macroevolutionary patterns in South American lineages in BAMM and GeoSSE; and (iv) re-evaluate the ancestral state of the mode of reproduction of mabuyines.ResultsOur results corroborated the hypothesis that the occupation of the South American continent by Mabuyinae consisted of two independent dispersion events that occurred between the Oligocene and the Miocene. We found significant differences in speciation rates between the New World and the remaining Mabuyinae clades only in GeoSSE. The influence of phenotypic traits on diversification rates was not supported by any method. Ancestral state reconstruction suggested that the ancestor of South American mabuyine was likely viviparous.DiscussionOur analyses further corroborated the existence of a transoceanic connection between Africa and South America in the Eocene/Oligocene period (Atlantogea). Following colonization of the isolated South America and subsequent dispersal through the continent by the ancestral mabuyine stock, we detected no difference in macroevolutionary regimes of New World clades. This finding argued against the ecological opportunity model as an explanation for the diversity of living mabuyines.
10
Jayathilaka, Ruwan, Oshada Athukorala, Sanduni Ishara, Dishani Silva, and Tanya Pathirage. "Alcohol brings burdens: A global and continent wise study on alcohol consumption and global burden of diseases." PLOS ONE 17, no. 7 (July 28, 2022): e0270998. http://dx.doi.org/10.1371/journal.pone.0270998.
Full textAbstract:
This article investigates alcohol consumption attributable burden of diseases. The present study considers the overall effect of Human Development Index (HDI), Socio Demographic Index (SDI) and Gross Domestic Product (GDP) for income to measure how these variables impact Global Burden of Diseases (GDB), bringing a different perspective to the results. Data from over 177 countries mainly including European, Asian, North American, South American, African and Australian regions were analysed from 2000 to 2019. A Panel regression technique was applied, and Fixed Effects (FE) and Random Effects (RE) estimations were chosen to derive outcomes of the Hausman test. The findings reflected that alcohol consumption (wine, beer, spirit and other alcohol) has a positive significant relationship with the Global Burden of Diseases (GBD) globally and in the African continent excluding North America and South America. Human Development Index (HDI) have a negative impact on GBD on all countries. Particularly HDI have a negative impact on GBD in African continent except other continents. Also, in the African continent and globally, GBD has a significant positive and in Europe, a significant negative impact on the Socio Demographic Index (SDI). The findings demonstrate the overall picture of the impact of alcohol consumption and other variables on GBD and provide suggestions on how these variables should be tackled in the future to reduce GBD. This is the initial empirical study that investigates the impact of alcohol consumption, analysing the combined effect of HDI, SDI and income on the GBD of continent wise and globally.
11
Ebojie, F., J. P. Burrows, C. Gebhardt, A. Ladstätter-Weißenmayer, C. von Savigny, A. Rozanov, M. Weber, and H. Bovensmann. "Global and zonal tropospheric ozone variations from 2003–2011 as seen by SCIAMACHY." Atmospheric Chemistry and Physics Discussions 15, no. 17 (September 7, 2015): 24085–130. http://dx.doi.org/10.5194/acpd-15-24085-2015.
Full textAbstract:
Abstract. An analysis of the tropospheric ozone (O3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during 2003–2011, focusing on the zonal and global variations in TOC is described. The changes are derived using a multivariate linear regression model. TOC shows a change of −0.2 ± 0.4 % yr−1, 0.3 ± 0.4 % yr−1, 0.1 ± 0.5 % yr−1 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2 σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1), the South American continent (up to 2 % yr−1), Alaska (up to 2 % yr−1) and around Congo in Africa (up to 2 % yr−1). Significant increase in TOC is derived from the continental outflows including those of Australia (up to 2 % yr−1), Eurasia (1–3 % yr−1) and the South America (up to 3 % yr−1). Significant decrease in TOC (up to −3 % yr−1) is observed over some regions of the continents of North America, Europe and South America. Over the Oceanic regions, significant decrease in TOC of about −2 % yr−1 is observed over the outflows of Europe and North America.
12
Landulfo, Eduardo, Fabio Lopes, Pablo Ristori, Eduardo Quel, Lidia Otero, Ricardo Forno, Maria Fernanda Sanchez, et al. "South American Aerosol Tracking - LALINET." EPJ Web of Conferences 176 (2018): 09009. http://dx.doi.org/10.1051/epjconf/201817609009.
Full textAbstract:
LALINET lidar stations were used to track down aerosols generated over Amazon region and transported over the continent. These data were merged with collocated Aeronet stations in order to help in their identification together with HYSPLIT simulations. The results show potential indication of how aerosol can age in their long transport over regions South and Westward from the source areas by change of their optical properties.
13
Hibbert, Liesel. "English in South Africa: parallels with African American vernacular English." English Today 18, no. 1 (January 2002): 31–36. http://dx.doi.org/10.1017/s0266078402001037.
Full textAbstract:
A comparison between Black English usage in South Africa and the United StatesThere has been a long tradition of resistance in South African politics, as there has been for African-Americans in the United States. The historical links between African Americans and their counterparts on the African continent prompt one to draw a comparison between the groups in terms of linguistic and social status. This comparison demonstrates that Black South African English (BSAfE) is a distinctive form with its own stable conventions, as representative in its own context as African American Vernacular English (AAVE) is in the United States.
14
Ferreira, Glauber W. S., and Michelle S. Reboita. "A New Look into the South America Precipitation Regimes: Observation and Forecast." Atmosphere 13, no. 6 (May 26, 2022): 873. http://dx.doi.org/10.3390/atmos13060873.
Full textAbstract:
South America is a vast continent characterized by diverse atmospheric phenomena and climate regimes. In this context, seasonal climate predictions are helpful for decision-making in several relevant socioeconomic segments in this territory, such as agriculture and energy generation. Thus, the present work evaluates the performance of ECMWF-SEAS5 in simulating the South American precipitation regimes by applying a non-hierarchical clustering technique. In addition, the study describes the main atmospheric systems that cause precipitation in each cluster and updates a previous work performed in South America in 2010. As a result, ECMWF-SEAS5 simulates (with good correspondence) the eight climate regimes identified in the analysis of precipitation from the Climate Prediction Center (CPC). Moreover, ECMWF-SEAS5 has a satisfactory ability in representing the rainfall regime in low and medium climate predictability regions, such as central and southern South America. ECMWF-SEAS5 has good performance in the climate characterization of South America and it gives us confidence in using its seasonal climate predictions throughout the continent.
15
Naranjo, José, and Ottorino Cosivi. "Elimination of foot-and-mouth disease in South America: lessons and challenges." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1623 (August 5, 2013): 20120381. http://dx.doi.org/10.1098/rstb.2012.0381.
Full textAbstract:
Foot-and-mouth disease (FMD) is a highly transmissible and economically devastating disease of cloven-hoofed livestock. Although vaccines are available and have been instrumental in eliminating the disease from most of the South American animal population, viral circulation still persists in some countries and areas, posing a threat to the advances of the last 60 years by the official veterinary services with considerable support of the livestock sectors. The importance of the disease for the social and economic development of the American continent led to the establishment in 1951 of the Pan American Centre for Foot-and-Mouth Disease (PANAFTOSA), which has been providing technical cooperation to countries for the elimination of the disease. The first FMD national elimination programmes were established in South America around the 1960s and 1970s. To advance the regional elimination efforts in the 1980s, countries agreed on a Plan of Action 1988–2009 of the Hemispheric Program for the Eradication of Foot-and-Mouth Disease. The Plan of Action 1988–2009 did not reach the goal of elimination from the continent; and a new Plan of Action 2011–2020 was developed in 2010 based on the experience acquired by the countries and PANAFTOSA during the past 60 years. This plan is now being implemented; several challenges are still to be overcome to ensure the elimination of FMD from the Americas by 2020, however, the goal is achievable.
16
Mosquera, K. "Numerical study of the response of the ocean to a northerly wind jet in the equatorial Eastern Pacific." Advances in Geosciences 14 (April 10, 2008): 239–42. http://dx.doi.org/10.5194/adgeo-14-239-2008.
Full textAbstract:
Abstract. The response of the equatorial and South American coastal ocean circulation to the anomalous March 2002 wind jet extending from the Gulf of Panama to 6° S is studied in a linear ocean model. Two experiments were performed: one without continental boundaries and the other with an eastern boundary at 81° W, representing the American continent. The spatial and temporal structure of the imposed wind anomaly, represented with idealized mathematical functions, is similar to that of the real jet. The duration of the wind jet was six days where the maximum intensity occurred at the third day. The results of the experiments indicate that the wind-jet anomaly over the Gulf of Panama is another source of ocean waves that influence the western coast of South America in the form of coastal Kelvin waves (CKW).
17
Zemp, D. C., C. F. Schleussner, H. M. J. Barbosa, R. J. Van der Ent, J. F. Donges, J. Heinke, G. Sampaio, and A. Rammig. "On the importance of cascading moisture recycling in South America." Atmospheric Chemistry and Physics Discussions 14, no. 11 (June 30, 2014): 17479–526. http://dx.doi.org/10.5194/acpd-14-17479-2014.
Full textAbstract:
Abstract. Continental moisture recycling is a crucial process of the South American climate system. Evapotranspiration from the Amazon river basin contributes to precipitation regionally and in the La Plata river basin. Here we present an in-depth analysis of South American moisture recycling. We quantify the importance of "cascading moisture recycling", which describes the exchange of moisture between the vegetation and the atmosphere through precipitation and re-evaporation cycles on its way between two locations on the continent. We use the Water Accounting Model 2-layers (WAM-2layers) forced by precipitation from TRMM and evapotranspiration from MODIS for the period 2001 until 2010 to construct moisture recycling networks. These networks describe the direction and amount of moisture transported from its source (evapotranspiration) to its destination (precipitation) in South America. Model-based calculations of continental and regional recycling ratios in the Amazon basin compare well with other existing studies using different datasets and methodologies. Our results show that cascading moisture recycling contributes about 10% to the total precipitation over South America and 17% over the La Plata basin. Considering cascading moisture recycling increases the total dependency of the La Plata basin on moisture from the Amazon basin by about 25% from 23 to 29% during the wet season. Using tools from complex network analysis, we reveal the importance of the south-western part of the Amazon basin as a key intermediary region for continental moisture transport in South America during the wet season. Our results suggest that land use change in this region might have a stronger impact on downwind rainfed agriculture and ecosystem stability than previously thought.
18
Lindo, John, and Michael DeGiorgio. "Understanding the Adaptive Evolutionary Histories of South American Ancient and Present-Day Populations via Genomics." Genes 12, no. 3 (March 2, 2021): 360. http://dx.doi.org/10.3390/genes12030360.
Full textAbstract:
The South American continent is remarkably diverse in its ecological zones, spanning the Amazon rainforest, the high-altitude Andes, and Tierra del Fuego. Yet the original human populations of the continent successfully inhabited all these zones, well before the buffering effects of modern technology. Therefore, it is likely that the various cultures were successful, in part, due to positive natural selection that allowed them to successfully establish populations for thousands of years. Detecting positive selection in these populations is still in its infancy, as the ongoing effects of European contact have decimated many of these populations and introduced gene flow from outside of the continent. In this review, we explore hypotheses of possible human biological adaptation, methods to identify positive selection, the utilization of ancient DNA, and the integration of modern genomes through the identification of genomic tracts that reflect the ancestry of the first populations of the Americas.
19
Dudek, Wanilton. "“Red Fascists”: anti-Nazi Germans under suspicion of the FBI." Revista História: Debates e Tendências 19, no. 4 (December 23, 2019): 659–65. http://dx.doi.org/10.5335/hdtv.19n.4.10491.
Full textAbstract:
Since the rise of Adolf Hitler in Germany in 1933, German opponents of Nazism had look for exile on the American continent, forming complex political movements across the American continent. The presence of the Free German Movement and the Council for the Democratic German in Los Angeles has alerted the US authorities, especially because of evidence of their links with communism and their relations with political movements in Latin America. The purpose of this paper is to analyze the role of the Federal Bureau of Investigation (FBI) in investigating German anti-Nazi exile groups in California and south of the United States border in the context of World War II.
20
Nobre, P., J. A. Marengo, I. F. A. Cavalcanti, G. Obregon, V. Barros, I. Camilloni, N. Campos, and A. G. Ferreira. "Seasonal-to-Decadal Predictability and Prediction of South American Climate." Journal of Climate 19, no. 23 (December 1, 2006): 5988–6004. http://dx.doi.org/10.1175/jcli3946.1.
Full textAbstract:
Abstract The dynamical basis for seasonal to decadal climate predictions and predictability over South America is reviewed. It is shown that, while global tropical SSTs affect both predictability and predictions over South America, the current lack of SST predictability over the tropical Atlantic represents a limiting factor to seasonal climate predictions over some parts of the continent. The model’s skill varies with the continental region: the highest skill is found in the “Nordeste” region and the lowest skill over southeastern Brazil. It is also suggested that current two-tier approaches to predict seasonal climate variations might represent a major limitation to forecast coupled ocean–atmosphere phenomena like the South Atlantic convergence zone. Also discussed are the possible effects of global climate change on regional predictability of seasonal climate.
21
WIEGLEB, GERHARD, MICHEL DESFAYES, and ALEXANDER A. BOBROV. "Ranunculus oblitus (section Batrachium, Ranunculaceae), a new species from South America." Phytotaxa 559, no. 2 (August 23, 2022): 132–44. http://dx.doi.org/10.11646/phytotaxa.559.2.2.
Full textAbstract:
Ranunculus oblitus, a new species of Ranunculus section Batrachium, is described from South America. The species is significantly different from the European laminar-leaved species R. aquatilis, and the Holarctic submerged species R. trichophyllus. It resembles the North Asian-North American species R. mongolicus differing by narrower petals, larger and fewer achenes. Available molecular data indicate affiliation to North American taxa of the R. trichophyllus group, especially R. porteri. The species occurs along the west coast of the continent from southern Peru to southern Chile, extending from sea level to an elevation of 4500 m a.s.l. in the Andes. There is some evidence that a second native Batrachium species occurs in South America.
22
Diogo, Rui. "Phylogeny, origin and biogeography of catfishes: support for a Pangean origin of 'modern teleosts' and reexamination of some Mesozoic Pangean connections between the Gondwanan and Laurasian supercontinents." Animal Biology 54, no. 4 (2004): 331–51. http://dx.doi.org/10.1163/1570756042729546.
Full textAbstract:
AbstractThe wide geographical distribution of the mainly freshwater catfishes has long intrigued the scientific community. This work provides a new insight into the phylogeny and the puzzling biogeographical distribution of catfishes. The important implications for teleost biogeography and plate tectonics are discussed. The results of the author's cladistic study on catfish higher level phylogeny, together with a revision of the data available concerning different fields such as palaeobiogeography, phylogeny, ecology and molecular biology, as well as the growing evidence supporting the existence of some remaining Pangean connections between Gondwana and Laurasia extending into the Early Cretaceous, strongly support a rather complex biogeographic scenario with multiple pre-drift and post-drift continental dispersions, vicariances, and, possibly, some marine migrations. According to this scenario: 1) catfishes originated in the South American region at a moment when there were still some remaining Pangean connections between Gondwana and Laurasia; 2) after this, there was a relatively rapid pre-drift continental dispersion of several, but not all, main groups of Siluriformes from the South-American region to Africa and other Gondwanan areas, with some of those groups succeeding in radiating ulteriorly via the remaining continental Pangean connections between Gondwana and Laurasia to this latter super-continent; 3) the final separation between Laurasia and Gondwana, and posteriorly between the regions constituting each of these super-continents, contributed to important vicariant events; 4) this scenario was still further complicated by numerous events such as the collision of India with Asia, the re-establishment of certain land connections between previously separated continents (e.g., between the Americas), and eventually also by some marine migrations, thus explaining the highly complex biogeographical distribution of the Siluriformes. In sustaining such a scenario, this work thus supports that, contrary to what is often accepted, some groups of 'modern teleosts' did have a Pangean origin.
23
Quartararo, Geraldine. "The Habitual ‘Saber + Infinitive’ in South American Spanish." International Journal of Linguistics 14, no. 4 (August 3, 2022): 17. http://dx.doi.org/10.5296/ijl.v14i4.19926.
Full textAbstract:
The present paper aims to describe both synchronic and diachronic distributions of the habitual aspectual periphrasis ‘saber + infinitive’ in the varieties of Spanish spoken in the South American continent. The data used for the present analysis come from the Corpus de Referencia del Español Actual and the Corpus del Español del Siglo XXI.
24
Liebmann, Brant, George N. Kiladis, Leila M. V. Carvalho, Charles Jones, Carolina S. Vera, Ileana Bladé, and Dave Allured. "Origin of Convectively Coupled Kelvin Waves over South America." Journal of Climate 22, no. 2 (January 15, 2009): 300–315. http://dx.doi.org/10.1175/2008jcli2340.1.
Full textAbstract:
Abstract Convectively coupled Kelvin waves over the South American continent are examined through the use of temporal and spatial filtering of reanalysis, satellite, and gridded rainfall data. They are most prominent from November to April, the season analyzed herein. The following two types of events are isolated: those that result from preexisting Kelvin waves over the eastern Pacific Ocean propagating into the continent, and those that apparently originate over Amazonia, forced by disturbances propagating equatorward from central and southern South America. The events with precursors in the Pacific are mainly upper-level disturbances, with almost no signal at the surface. Those events with precursors over South America, on the other hand, originate as upper-level synoptic wave trains that pass over the continent and resemble the “cold surges” documented by Garreaud and Wallace. As the wave train propagates over the Andes, it induces a southerly low-level wind that advects cold air to the north. Precipitation associated with a cold front reaches the equator a few days later and subsequently propagates eastward with the characteristics of a Kelvin wave. The structures of those waves originating over the Pacific are quite similar to those originating over South America as they propagate to eastern South America and into the Atlantic. South America Kelvin waves that originate over neither the Pacific nor the midlatitudes of South America can also be identified. In a composite sense, these form over the eastern slope of the Andes Mountains, close to the equator. There are also cases of cold surges that reach the equator yet do not form Kelvin waves. The interannual variability of the Pacific-originating events is related to sea surface temperatures in the central–eastern Pacific Ocean. When equatorial oceanic conditions are warm, there tends to be an increase in the number of disturbances that reach South America from the Pacific.
25
Xue, Yongkang, F. de Sales, W.-P. Li, C. R. Mechoso, C. A. Nobre, and H.-M. Juang. "Role of Land Surface Processes in South American Monsoon Development." Journal of Climate 19, no. 5 (March 1, 2006): 741–62. http://dx.doi.org/10.1175/jcli3667.1.
Full textAbstract:
Abstract This study explores the role of vegetation biophysical processes (VBPs) in the structure and evolution of the South American monsoon system (SAMS) with an emphasis on the precipitation field. The approach is based on comparing ensemble simulations by the National Centers for Environmental Prediction general circulation model (GCM) in which the land surface parameterization in one ensemble includes an explicit representation of vegetation processes in the calculation of surface fluxes while the other does not [GCM/Simplified Simple Biosphere Model (SSiB) and GCM/Soil, respectively], but with similar monthly mean surface albedo and initial soil moisture. The ensembles consist of five pairs of 1-yr integrations differing in the initial conditions for the atmosphere. The results show that, during the austral summer, consideration of explicit vegetation processes does not alter the monthly mean precipitation at the planetary scale. However, at continental scales, GCM/SSiB produces a more successful simulation of SAMS than GCM/Soil. The improvement is particularly clear in reference to the seasonal southward displacement of precipitation during the onset of the SAMS and its northward merging with the intertropical convergence zone during the monsoon mature stage, as well as better monthly mean austral summer precipitation over the South American continent. The changes in surface water and energy balances and circulation in October (monsoon onset) and December (the start of the monsoon mature stage) were analyzed for a better understanding of the results and mechanisms involved. It was found that the major difference between the simulations is in the partitioning of latent heat and sensible heat fluxes (i.e., different Bowen ratio), which produced different latitudinal and longitudinal thermal gradients at the surface. A stronger sensible heat flux gradient between continent and ocean in the GCM/SSiB simulation helped generate an enhanced ventilation effect, which lowered moist static energy (MSE) over the northeast coast of South America leading to stronger counterclockwise turning of the low-level wind from the Atlantic Ocean toward the continent during the premonsoon and early monsoon stages, modifying moisture flux convergence (MFC). It was further identified that the seasonality of savanna and shrublands to the south and east of the Amazon rain forest contributed to the variability of heating gradients and influenced the SAMS onset and its northward merge with the ITCZ at the early monsoon mature stage. The comparison of the differences between precipitation, evaporation, advection of MSE, and MFC based on simulations using two different land parameterizations suggested that the VBP modulated the surface water budget, but its impact on precipitation was determined by the changes in circulation via changes in heat gradient and MSE.
26
Ferreira Neto, José Soares. "Brucellosis and tuberculosis in cattle in South America." Brazilian Journal of Veterinary Research and Animal Science 55, no. 2 (July 26, 2018): e141139. http://dx.doi.org/10.11606/issn.1678-4456.bjvras.2018.141139.
Full textAbstract:
In general, European and North American countries, as well as Australia and New Zealand, have already eradicated or reached good levels of control of brucellosis and tuberculosis in cattle. In the rest of the world, however, the epidemiological situation of these two diseases is frequently poorly understood. In this review article, quantified data on these diseases in the South American countries are presented. Initially, the aspects that led the continent to host 25% of the world cattle population are presented, in addition to the aspects that placed the continent at a prominent position in the international meat market. Subsequently the continent was divided into three country groups, considering the size of the cattle population and how well the epidemiological situation of brucellosis and tuberculosis in cattle is quantified. It is argued that countries that do not generate high-quality quantitative epidemiological data on these diseases have serious limitations in outlining and managing control or eradication strategies. Thus, for successful outcomes, at least methodologies to estimate the prevalence of infected herds should be employed.
27
Guyot, Jean, and Vincent Le Guen. "A Review of a Century of Studies on South American Leaf Blight of the Rubber Tree." Plant Disease 102, no. 6 (June 2018): 1052–65. http://dx.doi.org/10.1094/pdis-04-17-0592-fe.
Full textAbstract:
In the past, South American leaf blight (SALB) of the rubber tree has been responsible for very severe damage in rubber plantations in South America. It is still the main obstacle holding back the development of rubber cultivation on the American continent and is a major risk for Asia and Africa, which are still exempt from this scourge. However, knowledge about the disease and about rubber tree resistance factors has progressed over the last decade, suggesting some solutions, notably for varietal improvement. This article is an overview of knowledge on this subject, particularly the most recent achievements.
28
CHRISTOFFERSEN, MARTIN L. "Species diversity and distributions of microdrile earthworms (Annelida, Clitellata, Enchytraeidae) from South America." Zootaxa 2065, no. 1 (April 6, 2009): 51–68. http://dx.doi.org/10.11646/zootaxa.2065.1.3.
Full textAbstract:
A comprehensive biodiversity database of Enchytraeidae produced 66 nominal species reported to date from South America (Achaeta, 6 species; Buchholzia, 1; Cognettia, 1; Enchytraeus, 3; Fridericia, 5; Grania, 1; Guaranidrilus, 10; Hemienchytraeus, 12; Henlea, 2; Lumbricillus, 7; Marionina, 12; Stephensoniella, 1; Timmodrilus, 1; Tupidrilus, 4). Almost 76% of this fauna (50 species) is endemic to the South American continent. The remaining 16 species are more or less largely distributed. Detailed South American occurrences are provided. This is the first reassessment of South American enchytraeids in 27 years. The group is conspicuoulsy absent from the northeast region of Brazil. Enchytraeidae are microdrile earthworms, representing the sister group of the Crassiclitellata, or megadrile earthworms. This relationship is supported by molecular phylogenies, ontogenetic transformations, ecological evidence, and several morphological synapomorphies (dorsal pores, contractil dorsal vessel, lateral position of dorsal chaetal bundles, and shape of chaetae).
29
Pandita, Ramesh, and Shivendra Singh. "Oncology Research Output and its Citation Analysis at Continental Level: A Study (2003-2012)." International Letters of Natural Sciences 17 (June 2014): 139–51. http://dx.doi.org/10.18052/www.scipress.com/ilns.17.139.
Full textAbstract:
The present study examines the research output and citation analysis in the field of Oncology, a branch of medical science which deals with the study and treatment of tumours, what we commonly know as cancer. Cancer as a disease is not confined to a particular region or a country, but is a global phenomenon and is still beyond the complete understanding and control of medicos. Research in the field of biomedical sciences in general and oncology is particular is undertaken at global level with almost each country contributing its bit in understating and control of disease. The study makes an empirical assessment of the research output and growth in the field of oncology at continental level for the period 2003-2012 and evaluates the aspects like research growth, citation analysis, h-Index etc. Data for the present study has been retrieved from the SCImago Journal and Country Ranking, which is totally based on the SCOPUS data source. Findings: - A total of 310593 research papers were published across six continents of the world during the period 2003-2012. Europe emerged the largest continent with its publication share of (124598, 40.11 %). Europe is followed by North America with its share percentage of (102897, 33.12 %) and Asia with (70555, 22.71 %). The contribution of Oceania, South America & Africa to the world oncology research is not that encouraging, as such there is greater need to promote oncology research in these continents. African contribution to global oncology research during the period remained (2215, 0.71 %), South American (3009, 0.96 %) and Oceania contributed (7319, 2.35 %). Oncology research publication on average during the period of study grew annually at 8.15 %, while as at continental level Africa registered highest annual publication growth of 19.08 %. North America and Europe are the only continents which recorded publication's growth below the average global growth.
30
Pandita, Ramesh, and Shivendra Singh. "Oncology Research Output and its Citation Analysis at Continental Level: A Study (2003-2012)." International Letters of Natural Sciences 17 (June 30, 2014): 139–51. http://dx.doi.org/10.56431/p-v7898o.
Full textAbstract:
The present study examines the research output and citation analysis in the field of Oncology, a branch of medical science which deals with the study and treatment of tumours, what we commonly know as cancer. Cancer as a disease is not confined to a particular region or a country, but is a global phenomenon and is still beyond the complete understanding and control of medicos. Research in the field of biomedical sciences in general and oncology is particular is undertaken at global level with almost each country contributing its bit in understating and control of disease. The study makes an empirical assessment of the research output and growth in the field of oncology at continental level for the period 2003-2012 and evaluates the aspects like research growth, citation analysis, h-Index etc. Data for the present study has been retrieved from the SCImago Journal and Country Ranking, which is totally based on the SCOPUS data source. Findings: - A total of 310593 research papers were published across six continents of the world during the period 2003-2012. Europe emerged the largest continent with its publication share of (124598, 40.11 %). Europe is followed by North America with its share percentage of (102897, 33.12 %) and Asia with (70555, 22.71 %). The contribution of Oceania, South America & Africa to the world oncology research is not that encouraging, as such there is greater need to promote oncology research in these continents. African contribution to global oncology research during the period remained (2215, 0.71 %), South American (3009, 0.96 %) and Oceania contributed (7319, 2.35 %). Oncology research publication on average during the period of study grew annually at 8.15 %, while as at continental level Africa registered highest annual publication growth of 19.08 %. North America and Europe are the only continents which recorded publication's growth below the average global growth.
31
Rial, J. A., and M. H. Ritzwoller. "Propagation efficiency of long-periodLgwaves in the South American continent." Geophysical Journal International 131, no. 2 (November 1997): 401–8. http://dx.doi.org/10.1111/j.1365-246x.1997.tb01231.x.
Full text
32
de la Fuente, Constanza, María C. Ávila-Arcos, Jacqueline Galimany, Meredith L. Carpenter, Julian R. Homburger, Alejandro Blanco, Paloma Contreras, et al. "Genomic insights into the origin and diversification of late maritime hunter-gatherers from the Chilean Patagonia." Proceedings of the National Academy of Sciences 115, no. 17 (April 9, 2018): E4006—E4012. http://dx.doi.org/10.1073/pnas.1715688115.
Full textAbstract:
Patagonia was the last region of the Americas reached by humans who entered the continent from Siberia ∼15,000–20,000 y ago. Despite recent genomic approaches to reconstruct the continental evolutionary history, regional characterization of ancient and modern genomes remains understudied. Exploring the genomic diversity within Patagonia is not just a valuable strategy to gain a better understanding of the history and diversification of human populations in the southernmost tip of the Americas, but it would also improve the representation of Native American diversity in global databases of human variation. Here, we present genome data from four modern populations from Central Southern Chile and Patagonia (n = 61) and four ancient maritime individuals from Patagonia (∼1,000 y old). Both the modern and ancient individuals studied in this work have a greater genetic affinity with other modern Native Americans than to any non-American population, showing within South America a clear structure between major geographical regions. Native Patagonian Kawéskar and Yámana showed the highest genetic affinity with the ancient individuals, indicating genetic continuity in the region during the past 1,000 y before present, together with an important agreement between the ethnic affiliation and historical distribution of both groups. Lastly, the ancient maritime individuals were genetically equidistant to a ∼200-y-old terrestrial hunter-gatherer from Tierra del Fuego, which supports a model with an initial separation of a common ancestral group to both maritime populations from a terrestrial population, with a later diversification of the maritime groups.
33
Matallana, Andrea. "BUILDING ART DIPLOMACY: THE CASE OF CONTEMPORARY AMERICAN ART EXHIBITION IN LATIN AMERICA, 1941." ShodhKosh: Journal of Visual and Performing Arts 3, no. 2 (October 20, 2022): 272–86. http://dx.doi.org/10.29121/shodhkosh.v3.i2.2022.172.
Full textAbstract:
This article analyzes the construction of the visual narrative expressed in the exhibition Contemporary North American Painting in 1941. During the II World War, the U.S. government recovered the initiative to build a strong tight with Latin American countries by relaunching the Good Neighbor Policy. Cultural diplomacy was an important branch of this policy. With the purpose of winning friends in the continent, the government created the Office of Inter-American Affairs, led by Nelson Rockefeller, and he sent artists, intellectuals, and exhibitions to make North America known in the other Americas. The Contemporary North American Painting projected an image of the United States as a modern and industrialized society to South Americans. This narrative was one of the devices developed by the U.S. government as part of the soft diplomacy carried out in the 1940s.In this article, we delve into the construction of the visual narrative about the U.S as part of the Good Neighbor exhibition complex, and we will analyze how the exhibition process was thought of as part of representational and ideological machinery.The article was based on reading, analysis, and cataloging of primary sources. The sources were letters, catalogs, photos, and notes from the main characters of the Office of Inter-American Affairs. Likewise, the exhibited works of art were operationalized.
34
FREITAS-SILVA, RAFAEL A. P., and ROSALY ALE-ROCHA. "New South American species of Crossopalpus Bigot (Diptera: Hybotidae: Tachydromiinae), including biogeographical insights and a reinterpretation of female abdominal tergite 10 in Drapetidini." Zootaxa 4559, no. 1 (February 18, 2019): 111. http://dx.doi.org/10.11646/zootaxa.4559.1.4.
Full textAbstract:
Crossopalpus is a rather diverse genus of tachydromiine flies, but regionally the genus is nowhere very speciose. Knowledge on the South American Crossopalpus before this paper included two described species from Andean related habitats, with several biomes from the eastern part of the continent being completely unexplored. Herein, we describe four new species of Crossopalpus from eastern South America, namely: C. albivertex sp. nov., C. aliceae sp. nov., C. goliathus sp. nov., and C. xanthogaster sp. nov. New diagnoses and high quality photographs are made available for C. armipes (Bezzi, 1909) and C. pennescens (Melander, 1918), including some characters used for the first time to distinguish South American species. We provide a key for identification of the six South American species, discussion about the position of Crossopalpus in Drapetidini, and some biogeographical insights including preferred habitats and seasonality of the South American species. We discuss the apparent loss of tergite 10 in females of Drapetidini, introducing a reinterpretation where the sclerite may be present in some genera of the tribe, but fused to the cerci and/or sternite 10.
35
Nader, Helen. "The End of the Old World." Renaissance Quarterly 45, no. 4 (1992): 791–807. http://dx.doi.org/10.2307/2862637.
Full textAbstract:
We are now, in 1992, searching to find the meaning of an event 500 years distant in time. For us as Americans the importance of the Columbian voyages is obvious. In the past ten years the great wealth of research, publication, and debate on ancient American cultures has made the impact on the Americas abundantly clear.For Europe the impact is much less clear. We say that the old world ended almost immediately, that a new world came into being when Europe ended its isolation from America. By this we mean that European perceptions of world geography began to change as early as 1498 —not just dotting the map of the Ocean Sea with more islands, but perceiving that South America was a continent whose existence was never imagined by the ancients. We also mean that the natural world began changing from the old world of two separate ecologies into a new world-wide environment.
36
Deininger, Michael, Brittany Marie Ward, Valdir F. Novello, and Francisco W. Cruz. "Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems—New Perspectives using the SISAL Database." Quaternary 2, no. 1 (January 28, 2019): 6. http://dx.doi.org/10.3390/quat2010006.
Full textAbstract:
Here we present an overview of speleothem δ18O records from South America, most of which are available in the Speleothem Isotopes Synthesis and Analysis (SISAL_v1) database. South American tropical and subtropical speleothem δ18O time series are primarily interpreted to reflect changes in precipitation amount, the amount effect, and consequently history of convection intensity variability of convergence zones such as the Intertropical Convergence Zone (ITCZ) and the South America Monsoon System (SAMS). We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time periods: Late Pleistocene, Holocene, and the last two millennia. Precession driven summertime insolation is the main driver of convective variability over the continent during the last 120 kyrs (from present day to 120 kyrs BP), including the Holocene. However, there is a dipole between speleothem δ18O records from western and eastern South America. Records located in the central region of Brazil are weakly affected by insolation-driven variability, and instead are more susceptible to the variability associated with the South Atlantic Convergence Zone (SACZ). Cold episodic events in the Northern Hemisphere, such as Heinrich and Bond Events, and the Little Ice Age, increase the convective activity of the SAMS, resulting in increased precipitation amount in South America.
37
Easterbrook, Rhiannon. "Reception." Greece and Rome 69, no. 1 (March 7, 2022): 167–71. http://dx.doi.org/10.1017/s0017383521000346.
Full textAbstract:
While this issue's selection of books on classical reception is diverse in subject area and methodology, one theme they all share is a focus on place and space. The Classics in South America by Germán Campos Muñoz and Time and Antiquity in American Empire by Mark Storey are particularly focused on Classics and the spatiality of empire. South America's location beyond the extent of the world known to the Roman Empire provided an interesting point of departure for the classically inclined inhabitants of the continent as they considered continuities and disjunctures with the time and space of classical antiquity. Campos Muñoz's second and third case studies discuss an array of material and literary evidence in examining how both colonial and anti-imperial activities were framed with respect to ancient history and epic. We see how a sixteenth-century Spanish nobleman celebrated becoming Viceroy of Peru in a procession through a triumphal arch adorned with Latin hexameter and classical motifs. Similarly, Simón Bolívar, the revolutionary and subject of classical odes celebrating his liberation of South American territories, enjoyed classicizing triumphs and parades (140). These contrasting case studies show the ongoing significance of the Roman Empire to South America, even as its imperial status changed dramatically.
38
Solman, Silvina A., and Isidoro Orlanski. "Subpolar High Anomaly Preconditioning Precipitation over South America." Journal of the Atmospheric Sciences 67, no. 5 (May 1, 2010): 1526–42. http://dx.doi.org/10.1175/2009jas3309.1.
Full textAbstract:
Abstract The mechanisms associated with the intraseasonal variability of precipitation over South America during the spring season are investigated with emphasis on the influence of a quasi-stationary anomalous circulation over the southeastern South Pacific Ocean (SEP). A spectral analysis performed to the bandpass-filtered time series of daily precipitation anomalies for the La Plata Basin (LPB) and the South Atlantic convergence zone (SACZ) regions revealed several statistically relevant peaks corresponding to periods of roughly 23 days and 14–16 days—with the lower (higher) frequency peaks more prevalent for the SACZ (LPB). The large-scale circulation patterns preconditioning precipitation variability over both regions were explored by means of a regression analysis performed on the daily 500-hPa geopotential anomaly field provided by the NCEP–NCAR reanalysis dataset. The most prominent feature of the regression fields is the presence of a quasi-stationary anomalous anticyclonic (cyclonic) circulation over the southeastern South Pacific Ocean associated with positive rainfall anomalies over the LPB (SACZ) and, emanating from that high (low), an external Rossby wave propagating northeastward toward the South American continent. The synoptic-scale activity, quantified in terms of a frontal activity index, showed a strong influence on precipitation over the LPB and to a lesser extent over the SACZ. Moreover, the frontal activity is actually modulated by the anomalous high circulation over the SEP region. The behavior of this anomalous circulation may be supported by a positive feedback mechanism that can enhance the response of the high anomaly itself, which in turns reinforces the Rossby wave train propagating toward the South American continent.
39
Hsu, Yu-Chen, Chung-Pan Lee, You-Lin Wang, Chau-Ron Wu, and Hon-Kit Lui. "Leading El-Niño SST Oscillations around the Southern South American Continent." Sustainability 10, no. 6 (May 29, 2018): 1783. http://dx.doi.org/10.3390/su10061783.
Full text
40
Kane, R. P. "Variability of theS q focus position in the South American continent." Journal of Earth System Science 99, no. 3 (September 1990): 405–12. http://dx.doi.org/10.1007/bf02841868.
Full text
41
Dillon, Denise. "Wilderness in 19th Century South Seas Literature: An Ecocritical Search for Seascapes." eTropic: electronic journal of studies in the Tropics 21, no. 1 (March 30, 2022): 248–372. http://dx.doi.org/10.25120/etropic.21.1.2022.3823.
Full textAbstract:
In Western thought and literature, a terrestrial bias is considered a phenomenological primacy for notions such as wilderness. This ecocritical review draws on nineteenth-century South Seas literature with its influences from frontierism and the literary movements of romanticism, realism and naturism to consider a more fluid appreciation and reconceptualisation of wilderness as non-terrestrial and an oceanic touchstone for freedom. American terrestrial frontierism, that drove colonial settlement of the North American continent, is used as both counterpoint and important embarkation point for ventures into the Pacific Ocean following ‘fulfilment’ of the ‘manifest destiny’ to overspread the continent. For American, British and Australian writers, the Pacific represented an opportunity to apply literary techniques to capture new encounters. South Seas works by Melville, Stevenson, Becke and Conrad offer glimpses of seascapes that provide perceptions of heterotopias, archetypes and depictions of dispossessed itinerants at a moral frontier and wilderness that is both sublime and liberating, liminal and phenomenological.
42
Anton, AM, and HE Connor. "Floral Biology and Reproduction in Poa (Poeae: Gramineae)." Australian Journal of Botany 43, no. 6 (1995): 577. http://dx.doi.org/10.1071/bt9950577.
Full textAbstract:
Flowers in the cosmopolitan genus Poa L. are predominantly hermaphrodite but many departures from this sex form occur in the New World. Dioecism is primarily a South American breeding system with about three times as many dioecious species as in the rest of the world. Gynomonoecism is a Central and South American trait heavily represented in Andean Peru and Bolivia. This zone of gynomonoecism separates dioecism in North and South America. Gynodioecism, a convenient evolutionary position on the pathway to dioecism, is relatively infrequent and in North America is of indeterminate form in several taxa. Apomixis has long been recognised in European Pea; in western North America, apospory has invaded dioecious species and generated populations of pistillate plants. In Peru and Bolivia, several taxa are composed exclusively of plants with pistillate flowers, but these have arisen from gynomonoecious progenitors. Poa is of Eurasian origin and migrated to North America and thence to South America. Sex-form kinds and frequencies are in stark contrast in the two parts of the continent, but are explicable in evolutionary terms. The selection pressures generating the deviations from hermaphroditism and their timing are unknown.
43
de Souza, William, Marcílio Fumagalli, Gilberto Sabino-Santos, Felipe Motta Maia, Sejal Modha, Márcio Teixeira Nunes, Pablo Murcia, and Luiz Moraes Figueiredo. "A Novel Hepacivirus in Wild Rodents from South America." Viruses 11, no. 3 (March 24, 2019): 297. http://dx.doi.org/10.3390/v11030297.
Full textAbstract:
The Hepacivirus genus comprises single-stranded positive-sense RNA viruses within the family Flaviviridae. Several hepaciviruses have been identified in different mammals, including multiple rodent species in Africa, Asia, Europe, and North America. To date, no rodent hepacivirus has been identified in the South American continent. Here, we describe an unknown hepacivirus discovered during a metagenomic screen in Akodon montensis, Calomys tener, Oligoryzomys nigripes, Necromys lasiurus, and Mus musculus from São Paulo State, Brazil. Molecular detection of this novel hepacivirus by RT-PCR showed a frequency of 11.11% (2/18) in Oligoryzomys nigripes. This is the first identification of hepavivirus in sigmondonine rodents and in rodents from South America. In sum, our results expand the host range, viral diversity, and geographical distribution of the Hepacivirus genus.
44
Suárez-Ibarra, Jaime Yesid, Gina Cardoso, Lidiane Asevedo, Lucas de Melo França, Mário André Trindade Dantas, Luis Enrique Cruz-Guevara, Andrés Felipe Rojas-Mantilla, and Ana Maria Ribeiro. "Quaternary proboscidean (Mammalia) remains of the UIS Geological Museum, Colombia." Revista Brasileira de Paleontologia 24, no. 1 (January 30, 2021): 70–75. http://dx.doi.org/10.4072/rbp.2021.1.06.
Full textAbstract:
Proboscideans arrived in South America from North America during the Great American Biotic Interchange, becoming one of the most representative animals of the megafauna that inhabited this continent throughout the Quaternary. In Colombia, the abundance of their remains contrasts with scarce scientific descriptions and publications. This paper identifies dental and postcranial proboscidean fossils from the Center and Northeast of Colombia. The fossil remains were identified as molars (six), a tusk, cervical vertebrae, and a distal part of the right humerus. The tusk was assigned to Notiomastodon platensis, while the other remains were assigned to Gomphotheriidae, with at least six individuals: two immatures, two subadults, and two older adults – mature and senile. Keywords: South America, megamammals, taxonomy, Gomphotheriidae, Notiomastodon platensis.
45
Colombo, Giulia, Luca Traverso, Lucia Mazzocchi, Viola Grugni, Nicola Rambaldi Migliore, Marco Rosario Capodiferro, Gianluca Lombardo, et al. "Overview of the Americas’ First Peopling from a Patrilineal Perspective: New Evidence from the Southern Continent." Genes 13, no. 2 (January 25, 2022): 220. http://dx.doi.org/10.3390/genes13020220.
Full textAbstract:
Uniparental genetic systems are unique sex indicators and complement the study of autosomal diversity by providing landmarks of human migrations that repeatedly shaped the structure of extant populations. Our knowledge of the variation of the male-specific region of the Y chromosome in Native Americans is still rather scarce and scattered, but by merging sequence information from modern and ancient individuals, we here provide a comprehensive and updated phylogeny of the distinctive Native American branches of haplogroups C and Q. Our analyses confirm C-MPB373, C-P39, Q-Z780, Q-M848, and Q-Y4276 as the main founding haplogroups and identify traces of unsuccessful (pre-Q-F1096) or extinct (C-L1373*, Q-YP4010*) Y-chromosome lineages, indicating that haplogroup diversity of the founder populations that first entered the Americas was greater than that observed in the Indigenous component of modern populations. In addition, through a diachronic and phylogeographic dissection of newly identified Q-M848 branches, we provide the first Y-chromosome insights into the early peopling of the South American hinterland (Q-BY104773 and Q-BY15730) and on overlying inland migrations (Q-BY139813).
46
Zemp, D. C., C. F. Schleussner, H. M. J. Barbosa, R. J. van der Ent, J. F. Donges, J. Heinke, G. Sampaio, and A. Rammig. "On the importance of cascading moisture recycling in South America." Atmospheric Chemistry and Physics 14, no. 23 (December 15, 2014): 13337–59. http://dx.doi.org/10.5194/acp-14-13337-2014.
Full textAbstract:
Abstract. Continental moisture recycling is a crucial process of the South American climate system. In particular, evapotranspiration from the Amazon basin contributes substantially to precipitation regionally as well as over other remote regions such as the La Plata basin. Here we present an in-depth analysis of South American moisture recycling mechanisms. In particular, we quantify the importance of cascading moisture recycling (CMR), which describes moisture transport between two locations on the continent that involves re-evaporation cycles along the way. Using an Eulerian atmospheric moisture tracking model forced by a combination of several historical climate data sets, we were able to construct a complex network of moisture recycling for South America. Our results show that CMR contributes about 9–10% to the total precipitation over South America and 17–18% over the La Plata basin. CMR increases the fraction of total precipitation over the La Plata basin that originates from the Amazon basin from 18–23 to 24–29% during the wet season. We also show that the south-western part of the Amazon basin is not only a direct source of rainfall over the La Plata basin, but also a key intermediary region that distributes moisture originating from the entire Amazon basin towards the La Plata basin during the wet season. Our results suggest that land use change in this region might have a stronger impact on downwind rainfall than previously thought. Using complex network analysis techniques, we find the eastern side of the sub-tropical Andes to be a key region where CMR pathways are channeled. This study offers a better understanding of the interactions between the vegetation and the atmosphere on the water cycle, which is needed in a context of land use and climate change in South America.
47
Lebrat, Michel, François Megard, and Claude Dupuy. "Pre-Orogenic Volcanic Assemblages and Position of the Suture Between Oceanic Terranes and the South American Continent in Ecuador." Zentralblatt für Geologie und Paläontologie, Teil I 1985, no. 9-10 (July 9, 1986): 1207–14. http://dx.doi.org/10.1127/zbl_geol_pal_1/1985/1986/1207.
Full text
48
Ebojie, F., J. P. Burrows, C. Gebhardt, A. Ladstätter-Weißenmayer, C. von Savigny, A. Rozanov, M. Weber, and H. Bovensmann. "Global tropospheric ozone variations from 2003 to 2011 as seen by SCIAMACHY." Atmospheric Chemistry and Physics 16, no. 2 (January 19, 2016): 417–36. http://dx.doi.org/10.5194/acp-16-417-2016.
Full textAbstract:
Abstract. An analysis of the tropospheric ozone (O3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during the period 2003–2011, focusing on global variations in TOC, is described. The changes are derived using a multivariate linear regression model. TOC shows changes of −0.2 ± 0.4, 0.3 ± 0.4, 0.1 ± 0.5 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1), the South American continent (up to 2 % yr−1), Alaska (up to 2 % yr−1) and around Congo in Africa (up to 2 % yr−1). Significant increase in TOC is determined off the continents including Australia (up to 2 % yr−1), Eurasia (1–3 % yr−1) and South America (up to 3 % yr−1). Significant decrease in TOC (up to −3 % yr−1) is observed over some regions of the continents of North America, Europe and South America. Over the oceanic regions including the Pacific, North Atlantic and Indian oceans, significant decreases in TOC (−1 to −3 % yr−1) were observed. In addition, the response of the El Niño–Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO) to changes in TOC for the period 2003–2011 was investigated. The result shows extensive regions, mostly in the tropics and Northern Hemisphere extratropics, of significant ENSO responses to changes in TOC and a significant QBO response to TOC changes over some regions.
49
Ramos, Víctor, Farid Chemale, Juan Pablo Lovecchio, and Maximiliano Naipauer. "The Malvinas (Falkland) Plateau Derived from Africa? Constraints for its Tectonic Evolution." Science Reviews - from the end of the world 1, no. 1 (November 29, 2019): 6–18. http://dx.doi.org/10.52712/sciencereviews.v1i1.23.
Full textAbstract:
The latest studies on the tectonic evolution of the Malvinas (Falkland) Islands and their adjacent continental plateau further east are analyzed to assess a long controversy regarding the origin of these islands. Although there has been a controversy for several decades on this subject, new technologies and exploratory drilling have brought new data, however the debate of the geological evolution of this area remains open. The two dominant hypotheses are analyzed by assessing the eventual collision between the islands and the South American continent, the presence of a large transcontinental fault such as Gastre, the potential 180º rotation of the Malvinas Islands, and the occurrence of a mega-decollement with opposite vergence. These hypotheses are contrasted with the processes that have occurred in Patagonia, especially those based on the new isotopic data on the Maurice Ewing Bank at the eastern end of the Malvinas Plateau, and the current knowledge of the adjacent Malvinas Basin. The new data highlights the inconsistencies of certain models that proposed these islands migrated from the eastern African coasts near Natal, to their current position and rotated 180º on a vertical axis. The new observations are consolidating the hypothesis that postulates that the islands have been part of the South American continent since before the Paleozoic.
50
Alessandretti, Luciano, Lucas V. Warren, Filipe G. Varejão, Raul Rassi, Maurício G. M. Dos Santos, Mariana N. M. Silva, Fernando R. Honorato, Michele J. T. Estrada, and João V. O. Cunha. "Uplifting mountains and shaking deserts: volcano-tectonic earthquakes revealed by soft-sediment-deformation structures in Upper Cretaceous aeolian deposits." Journal of Sedimentary Research 93, no. 1 (January 10, 2023): 1–19. http://dx.doi.org/10.2110/jsr.2021.143.
Full textAbstract:
ABSTRACT During the last stages of Gondwana fragmentation, large regions of the newly formed South American continent were covered by extensive deserts. Some parts of this continental landmass were synchronously affected by pronounced tectonism and magmatism, which were responsible for reshaping the regional topography. In this context, the southwestern part of the Sanfranciscana Basin in central Brazil is a key area for understanding this particular period in the geodynamic evolution of the South American continent. Aeolian deposits of the Posse Formation in the basin occur in direct association with volcanic rocks of the Upper Cretaceous Mata da Corda Group. Here, we report evidence of synsedimentary magmatism in direct association with soft-sediment-deformation structures, including flame structures, load casts and pseudonodules, water-escape structures, convolute lamination, faults, breccias, and clastic dikes, developed exclusively in aeolian sandstone and siltstone facies. The deformation features are interpreted as indicative of liquefaction, fluidization, and brittle behavior of the loose to partially lithified, wet sandy–silty sediments. The Late Cretaceous aeolian sedimentation is contemporaneous with the uplift of the Paranaíba High and associated magmatism in the Minas–Goiás Alkaline Province. In this context, these significant volcano-tectonic activities are considered to have triggered ductile to brittle deformation in the reported aeolian deposits.