Suchergebnisse

This study assesses the impact of low-frequency climate modes on Rossby Wave Packets (RWPs) during southern hemisphere summer. In particular, we focus on long-lived RWPs (lifespan above 8 days) and determine how El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) influence their statistics, that is, their duration, frequency of occurrence, and activity areas. We used daily mean meridional winds at 300 hPa from December to March between 1979 and 2020 from the ERA5 and NCEP-DOE 2 reanalyses. We found that long-lived wave packets, which are a small percentage of the total number of wave packets, show large interannual variability; there are years in which these types of waves do not occur and years that present up to 9 wave packets. This suggests that large-scale circulation conditions set up by low-frequency climate modes can modulate their occurrence. Classifying years according to SAM phases reveals that the occurrence of long-lived RWPs is highest (lowest) during intense negative (positive) SAM events. ENSO influence, on the other hand, was found to be weak and not robust. Analysis of large scale circulation conditions shows that during negative SAM phases the jet shifts northward, strengthens in the Indian sector, and extends further into the Pacific basin, so that it acts as a better waveguide favoring the propagation of long-lived RWPs. Conversely, during positive phases of SAM, the jet shifts southward and an anticyclonic center develops to the southwest of Australia blocking the jet and the progression of the wave packets. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 813844 (ITN CAFÉ). C.M acknowledges partial support from Span-ish Ministerio de Ciencia, Innovación y Universidades (PGC2018-099442-B-I00) and from ICREA ACADEMIA program of Generalitat de Catalunya. ; Postprint (published version)

Vols. 4 and 5, designed to contain the results of the astronomical observations, were not published. The material was published later by the U.S. Naval observatory in its Astronomical and meteorological observations. (Washington observations) for 1868, app. I, 1871, and Astronomical, magnetic and meteorological observations (Washington observations) for 1890, app. I, 1895. ; Lieut. Archibald MacRae, S.L. Phelps, E.R. Smith, assistants. ; I. Chile: its geography, climate, earthquakes, government, social condition, mineral and agricultural resources, commerce, &c., &c. [with Appendices A, B, C] by J.M. Gilliss. 1855.--II. Report of journeys across the Andes and pampas of the Argentine provinces, by Archibald MacRae. Appendices: D. Minerals, by L.J. Smith. E. Indian remains, by T Ewbank. F. Zoology: Mammals, by S.F. Baird. Birds, by J. Cassin. Reptiles, fishes, Crustacea, by C. Girard. Shells, by A.A. Gould. G. Botany: Dried plants, by Asa Gray. Living plants and seeds, by W.D. Brackenridge. H. Paleontology: Fossil mammals by J. Wymn. Fossil shells, by T.A. Conrad. 1855.--III. Observations to determine the solar parallax, J.M. Gilliss. 1856.--IV.-V. Not published. See note preceding contents.--VI. Magnetical and meteorological observations, under the direction of J.M. Gilliss. 1856. ; Mode of access: Internet.

Includes indexes. ; Archibald MacRae, S. L. Phelps, E. R. Smith, assistants. ; I. Chile: its geography, climate, earthquakes, government, social condition, mineral and agricultural resources, commerce, &c., &c. [with Appendices A, B, C] / by J. M. Gilliss -- II. Report of journeys across the Andes and pampas of the Argentine provinces / by Archibald MacRae. Appendices: D. Minerals / by L. J. Smith. E. Indian remains / by T. Ewbank. F. Zoology: Mammals / by S. F. Baird. Birds / by J. Cassin. Reptiles, fishes, Crustacea / by C. Girard. Shells. / by A. A. Gould. G. Botany: Dried plants / by Asa Gray. Living plants and seeds / by W. D. Brackenridge. H. Paleontology: Fossil mammals / by J. Wyman. Fossell shells / by T. A. Conrad. ; Mode of access: Internet.

Includes indexes. ; Archibald MacRae, S. L. Phelps, E. R. Smith, assistants. ; v. 1. Chile: its geography, climate, earthquakes, government, social condition, mineral and agricultural resources, commerce, &c., &c. / J. M. Gilliss -- v. 2. The Andes and pampas / Archibald MacRae -- Minerals / J. Lawrence Smith -- Indian remains / Thomas Ewbank -- Mammals / Spencer F. Baird -- Birds / John Cassin -- Reptiles, fishes, Crustacea / Charles Girard -- Shells. / A. A. Gould --Dried plants / Asa Gray -- Living plants and seeds / William D. Brackenridge -- Fossil mammals / James Wyman -- Fossell shells / T. A. Conrad. ; Mode of access: Internet.

Las acciones de Argentina en Africa han sido orientadas por algunos mitos sobre los beneficios de la cooperacion entre los paises del Sur. A partir del analisis de los vinculos establecidos desde los anos 60, la autora se refiere a estos mitos, a las tendencias mas significativas en las relaciones regionales y a los resultados de la cooperacion. Por una parte, interpreta las acciones a la luz de la historia argentina y, por otra, indaga acerca de la efectividad de las politicas para elucidar las permanencias y rupturas de la cooperacion con Africa. (UNISA Lat Am Rep/DÜI)

The COVID-19 pandemic that emerged in Wuhan China has generated substantial morbidity and mortality impact around the world during the last four months. The daily trend in reported cases has been rapidly rising in Latin America since March 2020 with the great majority of the cases reported in Brazil followed by Peru as of April 15(th), 2020. Although Peru implemented a range of social distancing measures soon after the confirmation of its first case on March 6(th), 2020, the daily number of new COVID-19 cases continues to accumulate in this country. We assessed the early COVID-19 transmission dynamics and the effect of social distancing interventions in Lima, Peru. We estimated the reproduction number, R, during the early transmission phase in Lima from the daily series of imported and autochthonous cases by the date of symptoms onset as of March 30(th), 2020. We also assessed the effect of social distancing interventions in Lima by generating short-term forecasts grounded on the early transmission dynamics before interventions were put in place. Prior to the implementation of the social distancing measures in Lima, the local incidence curve by the date of symptoms onset displays near exponential growth dynamics with the mean scaling of growth parameter, p, estimated at 0.9 (95%CI: 0.9,1.0) and the reproduction number at 2.3 (95% CI: 2.0, 2.5). Our analysis indicates that school closures and other social distancing interventions have helped slow down the spread of the novel coronavirus, with the nearly exponential growth trend shifting to an approximately linear growth trend soon after the broad scale social distancing interventions were put in place by the government. While the interventions appear to have slowed the transmission rate in Lima, the number of new COVID-19 cases continue to accumulate, highlighting the need to strengthen social distancing and active case finding efforts to mitigate disease transmission in the region.

Este artículo contiene 13 páginas, 4 tablas, 4 figuras. ; Taxonomic uncertainties and the lack of ecological knowledge can hinder the correct identification and the assignment of biogeographic status of marine species. The ascidian Asterocarpa humilis (Heller, 1878), originally described from New Zealand, has a broad distribution in shallow temperate areas of the Southern Hemisphere, having recently colonised areas of the Northern Hemisphere. A closely related species, Cnemidocarpa robinsoni Hartmeyer, 1916, has been reported in the South-Eastern Pacific and the South-Western Atlantic, and several authors considered it a junior synonym of A. humilis. We gathered for the first time morphological and genetic data from specimens from distant areas. We studied the morphology of specimens collected at seven locations of South America. We also re examined specimens from museum collections and revised the available literature on these species. Genetic data were obtained from specimens from Argentina and compared with available sequences of A. humilis from Chile, New Zealand, England and France. Morphological and genetic analyses showed that all compared specimens were conspecific. Furthermore, specimens from different continents shared haplotypes and exhibited low genetic distance among them. These results, the biological characteristics of this ascidian, and its longstanding presence in different habitats from disjoint areas, allow us to question its native range. We support the idea that A. humilis is a cryptogenic and neocosmopolitan species that has been transported by maritime traffic through the Southern Hemisphere, revealing frequent processes of exchange through this wide area for more than a century, with presumably associated alterations in the marine biota. ; This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional de Córdoba (UNC); and was partially funded by SECyT-UNC (grant number 33620180100077CB), EU Project IMCONet (Grant P7 IRSES, Action number 319718), IDEA WILD, iBOL (Res. 3404), PADI Foundation (Grant App# 32778/App# 40618), and project PopCOmics CTM2017-88080 (MCIU/AEI/FEDER) of the Spanish Government. ; Peer reviewed

Available Open Access under CC-BY-NC-ND licence. Bringing together a range of experts across various sectors, this important volume explores some of the key issues that have arisen in the Global South with the COVID-19 pandemic. Situating the worldwide health crisis within broader processes of globalisation, the book investigates implications for development and gender, as well as the effects on migration, climate change and economic inequality. Contributors consider how widespread and long-lasting responses to the pandemic should be, while paying particular attention to the accentuated risks faced by vulnerable populations. Providing answers that will be essential to development practitioners and policy makers, the book offers vital insights into how the impact of COVID-19 can be mitigated in some of the most challenging socio-economic contexts worldwide.