General description of some meteo-marine variables of surface waters adjacent to the Palmer Archipelago, Antarctic Peninsula, during 1979-2018 based on Era5 data

Aspatial and temporal description of meteo-marine parameters for 1979-2018 period of the marine region surrounding the Palmer Archipelago, located West of the Antarctic Peninsula (WAP), is presented. The used information was extracted from the ERA5 reanalysis. Air Temperature (Ta), Total Precipitation (TP) and Sea Surface Temperature (SST) showed a general increase over the last 40 years in the study region. The highest increase of Ta, TP and SST values were recorded north of Gerlache Strait, followed by Bismarck Strait. It was evidenced that Sea Ice Cover (SIC) has decreased mostly north of Palmer Archipelago. The existence of a local differentiation of meteo-marine conditions around the Palmer Archipelago was identified. The climatology of five reference points in the region showed more visible differences during the austral winter in Ta and SIC, these were appreciated during the austral summer in SST and a bimodal behavior was recorded in Pr. The rate of change during the 1979-2018 period for Ta was 0.011 ºC/year, for Pr it was 0.008 mm/year, for SST it was 0.004 ºC/year and for SIC it was -0.003 fraction/year.

Population inter-connectivity over the past 120,000 years explains distribution and diversity of Central African hunter-gatherers

The evolutionary history of African hunter-gatherers holds key insights into modern human diversity. Here we combine ethnographic and genetic data on Central African hunter-gatherers (CAHG) to show that their current distribution and density is explained by ecology rather than by a displacement to marginal habitats due to recent farming expansions, as commonly assumed. We also predicted hunter-gatherer presence across Central Africa over the past 120,000 years using paleoclimatic reconstructions, which were statistically validated by dated archaeological sites. Finally, we show that genomic estimates of separation times between CAHG groups match our ecological estimates of periods favouring population splits, and that recoveries of connectivity would have facilitated subsequent gene-flow. Our results reveal that CAHG stem from a deep history of partially connected populations. This form of sociality allowed the coexistence of relatively large effective population sizes and local differentiation, with important implications for the evolution of genetic and cultural diversity in Homo sapiens.

The Trini Sing-Song: Sociophonetic variation in Trinidadian English prosody and differences to other varieties

The current study provides a phonetic perspective on the questions of whether a high degree of variability in pitch may be considered a characteristic, endonormative feature of Trinidadian English (TrinE) at the level of speech production and contribute to what is popularly described as ‘sing-song’ prosody. Based on read and spontaneous data from 111 speakers, we analyze pitch level, range, and dynamism in TrinE in comparison to Southern Standard British (BrE) and Educated Indian English (IndE) and investigate sociophonetic variation in TrinE prosody with a view to these global F0 parameters. Our findings suggest that a large pitch range could potentially be considered an endonormative feature of TrinE that distinguishes it from other varieties (BrE and IndE), at least in spontaneous speech. More importantly, however, it is shown that a high degree of pitch variation in terms of range and dynamism is not as much characteristic of TrinE as a whole as it is of female Trinidadian speakers. An important finding of this study is that pitch variation patterns are not homogenous in TrinE, but systematically sociolinguistically conditioned across gender, age, and ethnic groups, and rural and urban speakers. The findings thus reveal that there is a considerable degree of systematic local differentiation in TrinE prosody. On a more general level, the findings may be taken to indicate that endonormative tendencies and sociolinguistic differentiation in TrinE prosody are interlinked.

Recent genetic connectivity and clinal variation in chimpanzees

Much like humans, chimpanzees occupy diverse habitats and exhibit extensive behavioural variability. However, chimpanzees are recognized as a discontinuous species, with four subspecies separated by historical geographic barriers. Nevertheless, their range-wide degree of genetic connectivity remains poorly resolved, mainly due to sampling limitations. By analyzing a geographically comprehensive sample set amplified at microsatellite markers that inform recent population history, we found that isolation by distance explains most of the range-wide genetic structure of chimpanzees. Furthermore, we did not identify spatial discontinuities corresponding with the recognized subspecies, suggesting that some of the subspecies-delineating geographic barriers were recently permeable to gene flow. Substantial range-wide genetic connectivity is consistent with the hypothesis that behavioural flexibility is a salient driver of chimpanzee responses to changing environmental conditions. Finally, our observation of strong local differentiation associated with recent anthropogenic pressures portends future loss of critical genetic diversity if habitat fragmentation and population isolation continue unabated.

Floristic similarity between adult and saplings strata of Caatinga hyperxerophilous woody vegetation – a Brazilian seasonally tropical dry forest

In the Caatinga, the maintenance of forest ecosystems depends on natural regeneration and several factors that can act in two ways: 1) provide the perpetuation of communities composheed of few species that dominate the adult and saplings strata, resulting in floristic similarities; 2) provide local differentiation between adult and saplings strata. However, these relationships remain poorly understood, as it is not known whether the factors acting on a local scale favor the floristic similarity between the adult and saplings strata or if these patterns are found in conserved and anthropized areas. This work evaluated the floristic similarity between the adult and saplings strata of hyperxerophilous caatinga woody-shrubby vegetation in conserved and anthropized areas. In two areasof conserved and anthropized hyperxerophilous Caatinga, adult and saplings individuals were measured and floristic richness and qualitative floristic similarity were evaluated. The floristic similarity between the adult and saplings strata was statistically compared using the Chao-Sørensen index. In both sites, although there was a large number of species exclusive to the adult stratum, the Chao-Sørensen index indicates high floristic similarity between strata. The analysis of this behavior together with the assessment of community structure shows that few species can be responsible for the key processes that structure and control the main mechanisms of persistence of these ecosystems. This can be attributed to the existence of locally uniform conditions that can define the dominance of adapted species groups.

Multiple introductions, regional spread and local differentiation during the first week of COVID-19 epidemic in Montevideo, Uruguay

BackgroundAfter its emergence in China in December 2019, the new coronavirus disease (COVID-19) caused by SARS-CoV-2, has rapidly spread infecting more than 3 million people worldwide. South America is among the last regions hit by COVID-19 pandemic. In Uruguay, first cases were detected on March 13 th 2020 presumably imported by travelers returning from Europe.MethodsWe performed whole-genome sequencing of 10 SARS-CoV-2 from patients diagnosed during the first week (March 16th to 19th) of COVID-19 outbreak in Uruguay. Then, we applied genomic epidemiology using a global dataset to reconstruct the local spatio-temporal dynamics of SARS-CoV-2.ResultsOur phylogeographic analysis showed three independent introductions of SARS-CoV-2 from different continents. Also, we evidenced regional circulation of viral strains originally detected in Spain. Introduction of SARS-CoV-2 in Uruguay could date back as early as Feb 20th. Identification of specific mutations showed rapid local genetic differentiation.ConclusionsWe evidenced early independent introductions of SARS-CoV-2 that likely occurred before first cases were detected. Our analysis set the bases for future genomic epidemiology studies to understand the dynamics of SARS-CoV-2 in Uruguay and the Latin America and the Caribbean region.