scholarly journals Intensity Variation of the Geomagnetic Field during the Past 4000 Years in South America

1968 ◽  
Vol 20 (1) ◽  
pp. 7-19 ◽  
Author(s):  
Kazuhiro KITAZAWA ◽  
Kazuo KOBAYASHI
Keyword(s):  
South America ◽  
Geomagnetic Field ◽  
Intensity Variation ◽  
The Past

IV.—The Geological Development, Descent and Distribution of the Mammalia

1893 ◽  
Vol 10 (9) ◽  
pp. 401-412 ◽  
Author(s):  
Karl A. von Zittel
Keyword(s):  
South America ◽  
The Past ◽  
Limited Experience ◽  
The World ◽  
Relationship Of ◽  
North And South America ◽  
The Relationship ◽  
North And South ◽  
Animal World

In a spirited treatise on the ‘Origin of our Animal World’ Prof. L. Rütimeyer, in the year 1867, described the geological development and distribution of the mammalia, and the relationship of the different faunas of the past with each other and with that now existing. Although, since the appearance of that masterly sketch the palæontological material has been, at least, doubled through new discoveries in Europe and more especially in North and South America, this unexpected increase has in most instances only served as a confirmation of the views which Rutimeyer advanced on more limited experience. At present, Africa forms the only great gap in our knowledge of the fossil mammalia; all the remaining parts of the world can show materials more or less abundantly, from which the course followed by the mammalia in their geological development can be traced with approximate certainty.

scholarly journals Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America

2018 ◽  
Vol 36 (3) ◽  
pp. 937-943 ◽  
Author(s):  
Maurício J. A. Bolzan ◽  
Clezio M. Denardini ◽  
Alexandre Tardelli
Keyword(s):  
South America ◽  
Geomagnetic Field ◽  
Phase Coherence ◽  
South American ◽  
Data Set ◽  
Geomagnetism And Paleomagnetism ◽  
Strong Phase ◽  
Geomagnetic Fields ◽  
Time Variations ◽  
Physical Phenomena

Abstract. The geomagnetic field in the Brazilian sector is influenced by the South American Magnetic Anomaly (SAMA) that causes a decrease in the magnitude of the local geomagnetic field when compared to other regions in the world. Thus, the magnetometer network and data set of space weather over Brazil led by Embrace are important tools for promoting the understanding of geomagnetic fields over Brazil. In this sense, in this work we used the H component of geomagnetic fields obtained at different sites in South America in order to compare results from the phase coherence obtained from wavelet transform (WT). Results from comparison between Cachoeira Paulista (CXP) and Eusébio (EUS), and Cachoeira Paulista and São Luis (SLZ), indicated that there exist some phenomena that occur simultaneously in both locations, putting them in the same phase coherence. However, there are other phenomena putting both locations in a strong phase difference as observed between CXP and Rio Grande, Argentina (RGA). This study was done for a specific moderate geomagnetic storm that occurred in March 2003. The results are explained in terms of nonlinear interaction between physical phenomena acting in distinct geographic locations and at different times and scales. Keywords. Geomagnetism and paleomagnetism (time variations – diurnal to secular)

scholarly journals A 21st Century Vision for Neotropical Snake Systematics

2018 ◽  
Vol 1 (1) ◽  
pp. 58
Author(s):  
Robert Alexander Pyron
Keyword(s):  
Species Richness ◽  
Natural History ◽  
Global Change ◽  
South America ◽  
Ecosystem Function ◽  
Museum Specimens ◽  
Fine Grained ◽  
The Past ◽  
The Caribbean ◽  
Recent Synthesis

We live in an unprecedented age for systematics and biodiversity studies. Ongoing global change is leading to a future with reduced species richness and ecosystem function (Pereira, Navarro, & Martins, 2012). Yet, we know more about biodiversity now than at any time in the past. For squamates in particular, we have range maps for all species (Roll et al., 2017), phylogenies containing estimates for all species (Tonini, Beard, Ferreira, Jetz, & Pyron, 2016), and myriad ecological and natural-history datasets for a large percentage of species (Meiri et al., 2013; Mesquita et al., 2016). For neotropical snakes, a recent synthesis of museum specimens and verified localities offers a fine-grained perspective on their ecogeographic distribution in Central and South America, and the Caribbean (Guedes et al., 2018).

scholarly journals Late Holocene summer temperatures in the central Andes reconstructed from the sediments of high-elevation Laguna Chepical, Chile (32° S)

2013 ◽  
Vol 9 (3) ◽  
pp. 2277-2308
Author(s):  
R. de Jong ◽  
L. von Gunten ◽  
A. Maldonado ◽  
M. Grosjean
Keyword(s):  
Climate Change ◽  
South America ◽  
Temperature Reconstruction ◽  
High Elevation ◽  
Ice Age ◽  
Central Chile ◽  
Southern South America ◽  
Calibration Period ◽  
The Past ◽  
Insight Into

Abstract. High-resolution reconstructions of climate variability that cover the past millennia are necessary to improve the understanding of natural and anthropogenic climate change across the globe. Although numerous records are available for the mid- and high-latitudes of the Northern Hemisphere, global assessments are still compromised by the scarcity of data from the Southern Hemisphere. This is particularly the case for the tropical and subtropical areas. In addition, high elevation sites in the South American Andes may provide insight into the vertical structure of climate change in the mid-troposphere. This study presents a 3000 yr long austral summer (November to February) temperature reconstruction derived from the 210Pb and 14C dated organic sediments of Laguna Chepical (32°16' S/70°30' W, 3050 m a.s.l.), a high-elevation glacial lake in the subtropical Andes of central Chile. Scanning reflectance spectroscopy in the visible light range provided the spectral index R570/R630, which reflects the clay mineral content in lake sediments. For the calibration period (AD 1901–2006), the R570/R630 data were regressed against monthly meteorological reanalysis data, showing that this proxy was strongly and significantly correlated with mean summer (NDJF) temperatures (R3yr = −0.63, padj = 0.01). This calibration model was used to make a quantitative temperature reconstruction back to 1000 BC. The reconstruction (with a model error RMSEPboot of 0.33 °C) shows that the warmest decades of the past 3000 yr occurred during the calibration period. The 19th century (end of the Little Ice Age (LIA)) was cool. The prominent warmth reconstructed for the 18th century, which was also observed in other records from this area, seems systematic for subtropical and southern South America but remains difficult to explain. Except for this warm period, the LIA was generally characterized by cool summers. Back to AD 1400, the results from this study compare remarkably well to low altitude records from the Chilean Central Valley and Southern South America. However, the reconstruction from Laguna Chepical does not show a warm Medieval Climate Anomaly during the 12–13th century, which is consistent with records from tropical South America. The Chepical record also indicates substantial cooling prior to 800 BC. This coincides with well-known regional as well as global glacier advances which have been attributed to a grand solar minimum. This study thus provides insight into the climatic drivers and temperature patterns in a region for which currently very few data are available. It also shows that since ca AD 1400, long term temperature patterns were generally similar at low and high altitudes in central Chile.

scholarly journals A Comparison of Equatorial Electrojet in Peru and East Brazil

2013 ◽  
Vol 7 (1) ◽  
pp. 29-36 ◽  
Author(s):  
R.G. Rastogi ◽  
H. Chandra ◽  
Rahul Shah ◽  
N.B. Trivedi ◽  
S.L. Fontes
Keyword(s):  
South America ◽  
Geomagnetic Field ◽  
Daily Variation ◽  
Equatorial Electrojet ◽  
Horizontal Component ◽  
Low Latitude ◽  
Vertical Field ◽  
The Mean ◽  
Western Side ◽  
The Magnetic Field

The paper describes the characteristics of the equatorial electrojet at Huancayo (HUA, 12.1oS, 75.3oW, inclination 1.5oN, declination 1.0oE) in western side of South America, where the geomagnetic field is aligned almost along the geographic meridian, and at Itinga (ITI, 4.3oS, 47.oW, inclination 1.4oN, declination 19.3oW) in eastern part of South America, where the geomagnetic field is aligned about 19o west of the geographic meridian; although the mean intensity of the magnetic field in the two regions are almost of the same order. Further comparisons are made of the current at Itinga and at Tatuoca (TTB, 1.2oS, 48.5oW, inclination 7.8o N, declination 18.7oW), a low latitude station in the same longitude sector. The daily range of horizontal component of the geomagnetic field, H, is shown to be almost 16% higher at HUA compared to that at ITI. The daily variation of the eastward field, Y, showed a strong minimum of -40 nT around 13-14 hr LT at ITI whereas very low values were observed at HUA with a positive peak of about 4 nT around 11- 12 hr LT. The vertical field, Z, showed abnormally large negative values of -70 nT at TTB around 13 hr LT. The day-today fluctuations of midday and midnight values of X field were positively correlated between HUA and ITI with a high correlation coefficient of 0.78 and 0.88 respectively. Values of Y field were also significantly positively correlated between HUA and ITI for midnight hours (0.72), while no correlation was observed for the midday hours. The midnight values of X field at HUA, ITI and TTB showed significant (0.90 or greater) correlation with Dst index. Correlation values of about 0.7 were observed between Dst and midday values of X at ITI and TTB and to a lesser degree (0.4) at HUA.

scholarly journals FERNÁNDEZ GARAY, Ana; CENSABELLA, Marisa (eds.) (2009). Estudios fonológicos de continua dialectales: mapuche y wichí. Santa Rosa: Universidad Nacional de La Pampa, 224. Pp. 2

2011 ◽  
Vol 11 (1) ◽  
pp. 173
Author(s):  
William Alfred Pickering
Keyword(s):  
South America ◽  
Theoretical Perspective ◽  
Indigenous Languages ◽  
Research Institutions ◽  
Sociolinguistic Variation ◽  
Systematic Survey ◽  
The Past ◽  
Dialect Variation ◽  
Phonological Change

This book is a collection of articles dealing with the phonology and dialectology of Wichí (referred to in the past as Mataco) and Mapuzungun (also called Mapudungun or Mapuche), two unrelated Amerindian languages of South America. Published by the Universidad Nacional de La Pampa, it is the end result of a three-year project funded by the Argentine government, the purpose of which was to study dialect variation in these languages. All of the authors are specialists in the indigenous languages of Argentina, and all but one are teachers or researchers at Argentine universities or research institutions. Adopting the “dynamic synchrony” approach of the French functionalist school as a methodological-theoretical perspective, the book pretends to give an overall view of the dialectical continua of the Argentine varieties of the languages under study and at the same time to provide some understanding of sociolinguistic variation and ongoing phonological change in both languages. The four articles on Wichí and the single article on Mapuzungun found in this volume, while falling short of constituting a systematic survey, make significant steps toward achieving these difficult and important goals.

scholarly journals COVID-19 and Immigrants’ Increased Exclusion: The Politics of Immigrant Integration in Chile and Peru

2021 ◽  
Vol 3 ◽  
Author(s):  
Luisa Feline Freier ◽  
Marcia Vera Espinoza
Keyword(s):  
South America ◽  
Economic Integration ◽  
Immigrant Integration ◽  
Economic Conditions ◽  
The Past

The COVID-19 pandemic has put into sharp relief the need for socio-economic integration of migrants, regardless of their migratory condition. In South America, more than five million Venezuelan citizens have been forced to migrate across the region in the past five years. Alongside other intra-regional migrants and refugees, many find themselves in precarious legal and socio-economic conditions, as the surge in numbers has led to xenophobic backlashes in some of the main receiving countries, including Chile and Peru. In this paper, we explore in how far the COVID-19 crisis has offered stakeholders an opportunity to politically reframe migration and facilitate immigrant integration or, rather, further propelled xenophobic sentiments and the socio-economic and legal exclusion of immigrants.

State Repression and the Struggles for Memory

2004 ◽  
Author(s):  
Elizabeth Jelin
Keyword(s):  
South America ◽  
21St Century ◽  
Truth Commission ◽  
Collective Identities ◽  
State Repression ◽  
News Stories ◽  
The Past ◽  
To Come ◽  
Political Realities ◽  
The Disappeared

Opening the newspapers in South America at the beginning of the 21st century can feel like being caught in static time: so many of the contemporary news stories point to the persistence of a past which is definitely not "over". The attempts to try Pinochet, the continuing searches for the disappeared, or a child of murdered parents' struggle to discover their real identity, the Truth Commission in Peru - across the continent, societies continue to come to terms with the past. This book provides an introduction to the complexity of ideas and approaches which have been brought to bear on memory and its importance for understanding social and political realities. Elizabeth Jelin draws on European and North American debates and theories to explore the ways in which conflicts over memory shape individual and collective identities, as well social and political cleavages. The book exposes the enduring consequences of repression and enriches our understanding of the conflicted and contingent nature of memory.

On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life

2010 ◽  
Author(s):  
Charles Darwin
Keyword(s):  
Natural Selection ◽  
South America ◽  
Origin Of Species ◽  
The Past

Introduction When on board H.M.S. ‘Beagle,’ as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me...

Certeau, Michel de (1925–86)

2018 ◽  
Author(s):  
Tom Conley
Keyword(s):  
North America ◽  
South America ◽  
Social Practice ◽  
The Other ◽  
General Philosophy ◽  
Late Medieval ◽  
The Past ◽  
Michel De Certeau ◽  
History Of ◽  
Strategic Policies

Michel de Certeau, a French philosopher trained in history and ethnography, was a peripatetic teacher in Europe, South America and North America. His thought has inflected four areas of philosophy. He studied how mysticism informs late-medieval epistemology and social practice. With the advent of the Scientific Revolution, the affinities the mystic shares with nature and the cosmos become, like religion itself, repressed or concealed. An adjunct discipline, heterology, thus constitutes an anthropology of alterity, studying the ‘other’ and the destiny of religion since the sixteenth century. De Certeau opens the hidden agendas that make representations of the past a function of social pressures, so that sometime histories are rearticulated in mirrored or subversive forms. This subversion makes accessible a general philosophy of invention that works within and against the strategic policies of official institutions. De Certeau’s writings also belong to activism, the history of ideological structures, psychoanalysis, and post-1968 theories of writing (écriture) as defined by Deleuze, Derrida, Foucault and Lyotard.

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