Models of hybridization during range expansions and their application to recent human evolution

Several lines of genetic, archeological and paleontological evidence suggest that anatomically modern humans (Homo sapiens) colonized the world in the last 60,000 years by a series of migrations originating from Africa (e.g. Liu et al., 2006; Handley et al., 2007; Prugnolle, Manica, and Balloux, 2005; Ramachandran et al. 2005; Li et al. 2008; Deshpande et al. 2009; Mellars, 2006a, b; Lahr and Foley, 1998; Gravel et al., 2011; Rasmussen et al., 2011). With the progress of ancient DNA analysis, it has been shown that archaic humans hybridized with modern humans outside Africa. Recent direct analyses of fossil nuclear DNA have revealed that 1–4 percent of the genome of Eurasian has been likely introgressed by Neanderthal genes (Green et al., 2010; Reich et al., 2010; Vernot and Akey, 2014; Sankararaman et al., 2014; Prufer et al., 2014; Wall et al., 2013), with Papua New Guineans and Australians showing even larger levels of admixture with Denisovans (Reich et al., 2010; Skoglund and Jakobsson, 2011; Reich et al., 2011; Rasmussen et al., 2011). It thus appears that the past history of our species has been more complex than previously anticipated (Alves et al., 2012), and that modern humans hybridized several times with local hominins during their expansion out of Africa, but the exact mode, time and location of these hybridizations remain to be clarifi ed (Ibid.; Wall et al., 2013). In this context, we review here a general model of admixture during range expansion, which lead to some predictions about expected patterns of introgression that are relevant to modern human evolution.

La lutte contre les abus dans le domaine de l’asile: émergence et développement d’un discours structurant le droit d’asile suisse

La « lutte contre les abus » en matière d'asile s'est imposée comme le discours dominant à l'origine des multiples révisions de la loi sur l'asile depuis son entrée en vigueur en 1981. Cette contribution, issue d'un workshop tenu lors des journées des doctorant-e-s du Centre de droit des migrations en novembre 2013, se propose de porter un regard interdisciplinaire sur l'émergence et le développement de cette notion, ainsi que sur le type de mesures adoptées dans le cadre de ce discours.

Migrantinnen in interkulturellen Vereinen: Perspektiven zur Integration in den Sport

Im deutschsprachigen Raum wird ein hoher Anteil an Migrantinnen, die sportlich inaktiv und in Sportvereinen unterrepräsentiert sind, konstatiert (Burrmann et al., 2015; Lamprecht et al., 2014). Migrantinnen ist der Zugang zu Sportaktivitäten häufig erschwert aufgrund von Diskriminierung, Konflikten und Grenzziehungsprozessen, denen Aspekte betreffend des Geschlechts und der Ethnizität inhärent sind. Vor diesem Hintergrund wurde bislang häufig das Potenzial der Integration in den Sport bzw. Sozialisation zum Sport von Migrantinnen in (ethnischen) Sportvereinen und im Schulsport untersucht. Wie jedoch die Integration in den Sport in interkulturellen Vereinen, welche Sportangebote offerieren, funktioniert, ist weder in der Migrations- noch in der sportbezogenen Integrationsforschung ein gängiges Thema. Basierend auf dem theoretischen Ansatz Boundary Work (Lamont & Molnár, 2002) untersucht die vorliegende Studie geschlechtsbezogene und ethnische Grenzziehungsprozesse hinsichtlich der Sportpartizipation von Migrantinnen in einem interkulturellen Verein sowie vereinsbezogene Möglichkeiten, welche die Integration in den Sport fördern. Es wurden halbstrukturierte Interviews mit acht Migrantinnen verschiedener Herkunft und zwei Leiterinnen eines interkulturellen Vereins in der deutschsprachigen Schweiz durchgeführt. Zusätzlich erfolgte eine Gruppendiskussion mit sechs Migrantinnen. Mittels qualitativer Inhaltsanalyse und dokumentarischer Methode wurden geschlechtsbezogene und ethnische Grenzen sowie Möglichkeiten für eine Sportpartizipation durch den Verein abgeleitet. Hinsichtlich der erschwerten Sportpartizipation indizieren die Resultate vielfältige, miteinander verschränkte, sich überlagernde und durchlässige Grenzen, die das Geschlecht und die Ethnizität allgemein betreffen. Im Speziellen wirken migrationsbedingt und lebensphasenspezifisch geprägte Haltungen gegenüber „mütterlichen“ Verpflichtungen, sprachlichen- und beruflichen Aus- bzw. Weiterbildungspflichten sowie Praktiken der Körperverhüllung. Die jeweilige Struktur der Grenzverschränkungen wirkt z.T. mehrfach restriktiv und prägt zugleich die verfügbare Zeit und finanzielle Mittel der Migrantinnen, was eine Dilemma artige Situation hervorruft. Zur Überwindung der Grenzen bietet der interkulturelle Verein insbesondere professionelle Mitarbeiterinnen; Kinderbetreuung; niederschwellige, kosten- und zeitgünstige Sportangebote exklusiv für Frauen; und eine wohlwollende Atmosphäre mit gleichberechtigtem Zusammensein. Interkulturelle Vereine können somit den Zugang zu Sportangeboten für Migrantinnen erleichtern und die Integration in den Sport bzw. die Sozialisation zum Sport fördern. Dies geschieht z.B. infolge bedarfsgerechter Vereinsangebote, unverbindlicher Teilnahmebedingungen und einer integrationsorientierten Vereinskultur. Der auf Grenzziehung fokussierte theoretische Ansatz und die vorliegenden Resultate eröffnen neue Forschungsperspektiven im Bereich Sport und Sozialisation sowie Integration.

Zum Potenzial der Integration von Migrantinnen in den Sport durch interkulturelle Vereine

Einleitung Im deutschsprachigen Raum besteht ein hoher Anteil an sportlich inaktiven und in Sportvereinen unterrepräsentierten Migrantinnen (Burrmann et al., 2015; Lamprecht et al., 2014). Migrantinnen ist der Zugang zu Sportaktivitäten häufig erschwert aufgrund von Diskriminierung, Konflikten und Grenzziehungen. Häufig wurde das Potenzial der Integration in den Sport bzw. Sozialisation zum Sport von Migrantinnen in (ethnischen) Sportvereinen und im Schulsport untersucht. Hingegen ist zur Integration in den Sport in interkulturellen Vereinen wenig bekannt. Basierend auf dem theoretischen Ansatz Boundary Work (Lamont & Molnár, 2002) wurden geschlechtsbezogene und ethnische Grenzziehungsprozesse hinsichtlich der Sportpartizipation von Migrantinnen in einem interkulturellen Verein sowie vereinsbezogene Möglichkeiten, welche die Integration in den Sport fördern, untersucht. Methode Es wurden halbstrukturierte Interviews mit acht Migrantinnen und zwei Leiterinnen eines interkulturellen Vereins in der Schweiz sowie eine Gruppendiskussion mit sechs Migrantinnen durchgeführt. Die Datenauswertung erfolgte mittels qualitativer Inhaltsanalyse und dokumentarischer Methode. Ergebnisse Die Resultate indizieren vielfältige, verschränkte, sich überlagernde und durchlässige Grenzen, die das Geschlecht und die Ethnizität allgemein betreffen. Im Speziellen wirken migrations- und lebensphasenspezifisch geprägte Haltungen gegenüber „mütterlichen“ Verpflichtungen, sprachlichen- und beruflichen Ausbildungspflichten sowie Praktiken der Körperverhüllung. Die jeweilige Struktur der Grenzverschränkungen wirkt z.T. mehrfach restriktiv. Zur Überwindung der Grenzen bietet der Verein z.B. professionelle Mitarbeiterinnen; Kinderbetreuung; niederschwellige, kosten- und zeitgünstige Sportangebote exklusiv für Frauen; und eine wohlwollende Atmosphäre mit gleichberechtigtem Zusammensein. Diskussion Interkulturelle Vereine können den Zugang zu Sportangeboten für Migrantinnen erleichtern und die Integration in den Sport bzw. die Sozialisation zum Sport fördern. Der auf Grenzziehung fokussierte theoretische Ansatz und die vorliegenden Resultate eröffnen neue Forschungsperspektiven im Bereich Sport und Sozialisation sowie Integration.

Climatic change and contemporaneous land-use phases north and south of the Alps 2300 BC to 800 AD

Fluctuations in the Δ14C curve and subsequent gaps of archaeological findings at 800–650 and 400–100 BC in western and central Europe may indicate major climate-driven land-abandonment phases. To address this hypothesis radiocarbon-dated sediments from four lakes in Switzerland were studied palynologically. Pollen analysis indicates contemporaneous phases of forest clearances and of intensified land-use at 1450–1250 BC, 650–450 BC, 50 BC–100 AD and around 700 AD. These land-use expansions coincided with periods of warm climate as recorded by the Alpine dendroclimatic and Greenland oxygen isotope records. Our results suggest that harvest yields would have increased synchronously over wide areas of central and southern Europe during periods of warm and dry climate. Combined interpretation of palaeoecological and archaeological findings suggests that higher food production led to increased human populations. Positive long-term trends in pollen values of Cerealia and Plantago lanceolata indicate that technical innovations during the Bronze and Iron Age (e.g. metal ploughs, scythes, hay production, fertilising methods) gradually increased agricultural productivity. The successful adoption of yield-increasing advances cannot be explained by climatic determinism alone. Combined with archaeological evidence, our results suggest that despite considerable cycles of spatial and demographic reorganisation (repeated land abandonments and expansions, as well as large-scale migrations and population decreases), human societies were able to shift to lower subsistence levels without dramatic ruptures in material culture. However, our data imply that human societies were not able to compensate rapidly for harvest failures when climate deteriorated. Agriculture in marginal areas was abandoned, and spontaneous reforestations took place on abandoned land south and north of the Alps. Only when the climate changed again to drier and warmer conditions did a new wide-spread phase of forest clearances and field extensions occur, allowing the reoccupation of previously abandoned areas. Spatial distribution of cereal cultivation and growth requirements of Cerealia species suggest that increases in precipitation were far more decisive in driving crop failures over central and southern Europe than temperature decreases.

Long distance dispersal shaped patterns of human genetic diversity in Eurasia

Most previous attempts at reconstructing the past history of human populations did not explicitly take geography into account, or considered very simple scenarios of migration and ignored environmental information. However, it is likely that the Last Glacial Maximum (LGM) affected the demography and the range of many species, including our own. Moreover, long-distance dispersal (LDD) may have been an important component of human migrations, allowing fast colonization of new territories and preserving high levels of genetic diversity. Here, we use a high-quality microsatellite dataset genotyped in 22 populations to estimate the posterior probabilities of several scenarios for the settlement of the Old World by modern humans. We considered models ranging from a simple spatial expansion to others including LDD and a LGM-induced range contraction, as well as Neolithic demographic expansions. We find that scenarios with LDD are much better supported by data than models without LDD. Nevertheless, we show evidence that LDD events to empty habitats were strongly prevented during the settlement of Eurasia. This unexpected absence of LDD ahead of the colonization wave front could have been caused by an Allee effect, either due to intrinsic causes such as an inbreeding depression built during the expansion, or to extrinsic causes such as direct competition with archaic humans. Overall, our results suggest only a relatively limited effect of the LGM-contraction on current patterns of human diversity. This is in clear contrast with the major role of LDD migrations, which have potentially contributed to the intermingled genetic structure of Eurasian populations.

European multicentre experience with the sutureless Perceval valve: clinical and haemodynamic outcomes up to 5 years in over 700 patients†.

OBJECTIVES This report summarizes the 5-year clinical and haemodynamic data from three prospective, European multicentre trials with the Perceval sutureless aortic valve. METHODS From April 2007 to August 2012, 731 consecutive patients (mean age: 78.5 years; 68.1% females; mean logistic EuroSCORE 10.9%) underwent AVR with the Perceval valve in 25 European centres. Isolated AVR was performed in 498 (68.1%) patients. A minimally invasive approach was performed in 189 (25.9%) cases. The cumulative follow-up was 729 patients-years. RESULTS In isolated AVR, mean cross-clamp and cardiopulmonary bypass times were 30.8 and 50.8 min in full sternotomy, and 37.6 and 64.4 min in the minimally invasive approach, respectively. Early cardiac-related deaths occurred in 1.9%. Overall survival rates at 1 and 5 years were 92.1 and 74.7%, respectively. Major paravalvular leak occurred in 1.4% and 1% at early and late follow-up, respectively. Significant improvement in clinical status was observed postoperatively in the majority of patients. Mean and peak gradients decreased from 42.9 and 74.0 mmHg preoperatively, to 7.8 and 16 mmHg at the 3-year follow-up. LV mass decreased from 254.5 to 177.4 g at 3 years. CONCLUSIONS This European multicentre experience, with the largest cohort of patients with sutureless valves to date, shows excellent clinical and haemodynamic results that remain stable even up to the 5-year follow-up. Even in this elderly patient cohort with 40% octogenarians, both early and late mortality rates were very low. There were no valve migrations, structural valve degeneration or valve thrombosis in the follow-up. The sutureless technique is a promising alternative to biological aortic valve replacement.

Hamlet's Mobility: The Reception of Shakespeare's Tragedy in US-American and Canadian Narrative Fiction

This essay presents a comprehensive study of how Hamlet figures in North American fiction. Gabriele Rippl takes her cue from Stephen Greenblatt’s notion of Shakespeare’s ‘theatrical mobility’ (Greenblatt, Cultural Mobility. Cambridge University Press, 2010). This initial mobility, based on the playwright’s own borrowings, appears to facilitate, or even instigate further migrations. Rippl proceeds to give an overview of adaptations of Shakespeare’s Hamlet in the USA and Canada, thus providing an insight into the historical and cultural uses to which the play has been put by authors such as John Updike or Margaret Atwood. Phenomena such as the ‘republicanization’ of Shakespeare (James Fenimore Cooper), or his appropriation for a feminist counter-discourse in Canada circumscribe a space for the negotiation of cultural and political identities.

Quantification of biotic responses to rapid climatic changes around the Younger Dryas — a synthesis

To assess the presence or absence of lags in biotic responses to rapid climatic changes, we: (1) assume that the δ18O in biogenically precipitated carbonates record global or hemispheric climatic change at the beginning and at the end of the Younger Dryas without any lag at our two study sites of Gerzensee and Leysin, Switzerland; (2) derive a time scale by correlating the δ18O record from these two sites with the δ18O record of the GRIP ice core; (3) measure δ18O records in ostracods and molluscs to check the record in the bulk samples and to detect possible hydrological changes; (4) analyse at Gerzensee and Leysin as well as at two additional sites (that lack carbonates and hence a δ18O record) pollen, plant macrofossils, chironomids, beetles and other insects, and Cladocera; (5) estimate our sampling resolution using the GRIP time scale for the isotope stratigraphies and the biostratigraphies; and (6) summarise the major patterns of compositional change in the biostratigraphies by principal component analysis or correspondence analysis. We conclude that, at the major climatic shifts at the beginning and end of the Younger Dryas, hardly any biotic lags occur (within the sampling resolution of 8–30 years) and that upland vegetation responded as fast as aquatic invertebrates. We suggest that the minor climatic changes associated with the Gerzensee and Preboreal oscillations were weakly recorded in the biostratigraphies at the lowland site, but were more distinct at higher altitudes. Individualistic responses of plant and animal species to climatic change may reflect processes in individuals (e.g. productivity and phenology), in populations (e.g. population dynamics), in spatial distributions (e.g. migrations), and in ecosystems (e.g. trophic state). We suggest that biotic responses may be telescoped together into relatively short periods (50 to 150 years), perhaps disrupting functional interactions among species and thus destabilising ecosystems.

Ökonomische Verwertung und die Rolle der rassistischen Migrationspolitiken

Wie hängen die Migrationspolitiken mit der ökonomischen Ausbeutung von Migrant_innen zusammen? Wie kann man die Kämpfe in den verschiedenen Bereichen zusammenbringen? Im Workshop sollen verschiedene Formen von Diskriminierung und Ausbeutung gesammelt, Erfahrungen ausgetauscht und Möglichkeiten für Widerstand diskutiert werden.

TRANSCRIPTIONAL REGULATION OF PROFILIN IS REQUIRED FOR DROSOPHILA LARVAL WOUND CLOSURE

Injury is an inevitable part of life, making wound healing essential for survival. In postembryonic skin, wound closure requires that epidermal cells recognize the presence of a gap and change their behavior to migrate across it. In Drosophila larvae, wound closure requires two signaling pathways (the Jun N-terminal kinase (JNK) pathway and the Pvr receptor tyrosine kinase signaling pathway) and regulation of the actin cytoskeleton. In this and other systems, it remains unclear how the signaling pathways that initiate wound closure connect to the actin regulators that help execute wound- induced cell migrations. Here we show that chickadee, which encodes the Drosophila Profilin, a protein important for actin filament recycling and cell migration during development, is required for the physiological process of larval epidermal wound closure. After injury, chickadee is transcriptionally upregulated in cells proximal to the wound. We found that JNK, but not Pvr, mediates the increase in chic transcription through the Jun and Fos transcription factors. Finally, we show that chic deficient larvae fail to form a robust actin cable along the wound edge and also fail to form normal filopodial and lamellipodial extensions into the wound gap. Our results thus connect a factor that regulates actin monomer recycling to the JNK signaling pathway during wound closure. They also reveal a physiological function for an important developmental regulator of actin and begin to tease out the logic of how the wound repair response is organized.

Planktonic foraminifera of IODP Site 306-U1314

Surface water conditions at the Integrated Ocean Drilling Program (IODP) Site U1314 (Southern Gardar Drift, 56° 21.8' N, 27° 53.3' W, 2820 m depth) were inferred using planktic foraminifer assemblages between Marine Isotope Stage (MIS) 19 and 11 (ca. 800-400 ka). Factor analysis of the planktic foraminifer assemblages suggests that the assemblage was controlled by three factors. The first factor (which explained 49% of the variance) is dominated by transitional and subpolar species and points to warm and salty surface water conditions (Atlantic water). The second factor (37%) is dominated by Neogloboquadrina pachyderma sin and has been associated with the presence of cold and low saline surface waters (Arctic water). Finally, the third factor (9%), linked to a significant presence of Turborotalita quinqueloba, reflects the closeness of the Arctic front (the boundary between Atlantic and Arctic water). The position of the Arctic and Polar fronts has been estimated across the glacial-interglacial cycles studied according to planktic foraminifer abundances from Site U1314 (and their factor analysis) combined with a synthesis of planktic foraminifer and diatom data from other North Atlantic sites. Regarding at the migrations of the Arctic front and the surface water masses distribution across each climatic cycle we determined five phases of development. Furthermore, deep ocean circulation changes observed in glacial-interglacial cycles have been associated with each phase. The high abundance of transitional-subpolar foraminifers (above 65% at Site U1314) during the early interglacial phase indicated that the Arctic front position and surface water masses distribution were similar to present conditions. During the late interglacial phase, N. pachyderma sin and T. quinqueloba slightly increased indicating that winter sea ice slightly expanded southwestwards whereas the ice volume remained stable or was still decreasing. N. pachyderma sin increased rapidly (above 65% at Site U1314) at the first phase of glacial periods indicating the expansion of the Arctic waters in the western subpolar North Atlantic. During the second phase of glacial periods the transitional-subpolar assemblage throve again in the central subpolar North Atlantic associated with strong warming events that followed ice-rafting events. The third phase of glacial periods corresponds to full glacial conditions in which N. pachyderma sin dominated the assemblage for the whole subpolar North Atlantic. This division in phases may be applied to the last four climatic cycles.

Filantropía y anarquismo : imaginario prometeico de Valparaíso en Edwards Bello, Swinglehurst, Rubén Darío, Víctor D. Silva y González Vera

Este artículo se propone dar cuenta de diferentes modalidades en que la representación literaria pone en tensión el imaginario prometeico del Valparaíso de fines del siglo XIX y principios del siglo XX, otorgando relevancia a algunos de los mitemas que lo conforman como filantropía o anarquismo, para lo cual se examinan textos de escritores implicados en las migraciones extranjera e interna (Edwards Bello, Swiglehurst, Darío, V. D. Silva y González Vera), que entran en diálogo con los espacios urbanos y el imaginario social de un Valparaíso signado por el progresismo y la modernización.