Bryn Athyn College

Abstract ObjectivesThe Bahamas is an archipelago in the western Atlantic Ocean that stretches over 1000 km, just north of Cuba and east of the Florida Peninsula. Modern DNA studies show that contemporary Bahamians are genetic descendants of European and African ancestors, unlike Cuba, Dominican Republic, and Puerto Rico, where Indigenous descendancy is well documented. For The Bahamas little was known about the genetic ancestry of the Indigenous Lucayans (AD 700–1600) and their relationship to other Indigenous Caribbean populations. In this study, we investigated genetic diversity in Indigenous Lucayans from the Bahamas Archipelago to better understand the phylogeography of their genetic lineages, and to determine their relationship with other Indigenous Caribbean populations.Materials and methodsWe characterized genetic diversity across two uniparental markers in 31 ancient individuals from burial sites on seven Bahamian islands.ResultsWe observed significant homogeneity in Lucayan paternal lineages, with only two haplogroups (Q‐M902 and Q‐Z781) found among them. Mitochondrial lineages were more diverse, with individuals belonging to haplogroup A2, B2, C1b, and C1d1. Four were assigned to a previously unidentified C1d lineage. Of the B2 samples, 7 of 11 belonged to the rare South America/Caribbean haplogroup B2e. This haplogroup was the most prevalent in the Northwest Bahamas while C1, particularly C1d, was more prevalent in the Central and Southern Bahamas.DiscussionThese findings document a complex genetic history with an initial migration from Hispaniola beginning 1300 years ago, and possible gene flow from Cuba to Andros in late Bahamian prehistory.

As educators and students navigated the changes amid COVID-19 and the switch to on-line learning, there became a critical need to identify and address the challenges experienced by all. This chapter highlights the findings and recommendations of a study that surveyed over 400 educators to gather their perceptions of the barriers presented by COVID-19 and their experiences as they adjusted to educating students during a pandemic. The COVID-19 Educator Impact Survey developed by the researchers focused on educators' perceptions of the impact of COVID-19 on instructional practices, emotional health, and student learning. Innovative practices to create a more equitable education with the intentional inclusion of Trauma Informed Practices and the newly created Guideposts for Trauma Informed Strategies are described. These guideposts can serve as recommendations for stakeholders with the goal of reimagining pedagogical practices and educational policies including trauma informed frameworks related to equity, access, and social-emotional learning skills for vulnerable populations.

In this study, we characterized genetic diversity in the Svans from northwestern Georgia to better understand the phylogeography of their genetic lineages, determine whether genetic diversity in the highland South Caucasus has been shaped by language or geography, and assess whether Svan genetic diversity was structured by regional residence patterns. We analyzed mtDNA and Y-chromosome variation in 184 individuals from 13 village districts and townlets located throughout the region. For all individuals, we analyzed mtDNA diversity through control region sequencing, and, for males, we analyzed Y-chromosome diversity through SNP and STR genotyping. The resulting data were compared with those for populations from the Caucasus and Middle East. We observed significant mtDNA heterogeneity in Svans, with haplogroups U1-U7, H, K, and W6 being common there. By contrast, ∼78% of Svan males belonged to haplogroup G2a, with the remainder falling into four other haplogroups (J2a1, I2, N, and R1a). While showing a distinct genetic profile, Svans also clustered with Caucasus populations speaking languages from different families, suggesting a deep common ancestry for all of them. The mtDNA data were not structured by geography or linguistic affiliation, whereas the NRY data were influenced only by geography. These patterns of genetic variation confirm a complex set of geographic sources and settlement phases for the Caucasus highlands. Such patterns may also reflect social and cultural practices in the region. The high frequency and antiquity of Y-chromosome haplogroup G2a in this region further points to its emergence there.

ECOLOGY propose that a predator which is dependent on just a single species as a food source is vulnerable to local extirpation or even extinction. Conversely, diversity of prey enhances stability of the predator. In this paper, I describe the diet of the Gyrfalcon and its variation in space and time, and speculate that the lack of prey diversity leaves the Gyrfalcon vulnerable to population instability, especially if climate change reduces the availability of its primary prey, ptarmigan. This paper is a general review of the literature data on the Gyrfalcon diet with some addition of personal experience with the species in North-East Siberia. Since we summarized the papers on the Gyrfalcon's diet (Potapov and Sale 2005), there have been a few new studies 55

THE GYRFALCON (Falco rusticolus), the largest falcon in the world, lives in the Arctic and sub-Arctic, and relies heavily on ptarmigan as its major food source, and a few other species, such as Ravens (Corvus corax), Rough-legged Hawks (Buteo lagopus), and some eagles, to build nests which it uses for breeding. Despite its dependence on prey species that exhibit cycles of abundance, the Gyrfalcon has enjoyed relative population stability, as its breeding range was too remote from potential human-caused threats. Within the Russian Federation, the Gyrfalcon's range covers c. 2,685,000 km 2 of tundra and forest-tundra, 191

For a brief period about a century ago, reputable scientists gave credence to the idea that wind was capable of regional planation. Among them was J.T. Jutson, whose publications exerted considerable influence both in Australia and overseas. He differentiated between deflation and corrasion (sand-blasting) and in 1914 attributed major as well as minor landscape features to their activity. He ascribed the westward migration of salinas and the shaping of associated rock platforms to the wind as well as to the extension of valleys that were incised into the lateritised Old Plateau and that coalesced to form the New Plateau of Western Australia. But local and overseas colleagues drew his attention to the primacy of rivers in shaping even desert landscapes, and by 1934 Jutson had realised that running water was almost solely responsible for the New Plateau.

Subject History of Science and Technology Physics Classical Mechanics Collection: Oxford Scholarship Online

Subject History of Science and Technology Physics Classical Mechanics Collection: Oxford Scholarship Online