102 resultados para West Mesoamerica
Resumo:
We use a network of cores from 77 peatland sites to determine controls on peat C content and peat C accumulation over the last 2000 years (since 2 ka) across Russia's West Siberian Lowland (WSL), the world's largest wetland region. Our results show a significant influence of fossil plant composition on peat C content, with peats dominated by Sphagnum having a lower C content. Radiocarbon-derived C accumulation since 2 ka at 23 sites is highly variable from site to site, but displays a significant N–S trend of decreasing accumulation at higher latitudes. Northern WSL peatlands show relatively small C accumulation of 7 to 35 kg C m-2 since 2 ka. In contrast, peatlands south of 60°N show larger accumulation of 42 to 88 kg C m-2. Carbon accumulation since 2 ka varies significantly with modern mean annual air temperature, with maximum C accumulation found between -1 and 0°C. Rates of apparent C accumulation since 2 ka show no significant relationship to long-term Holocene averages based on total C accumulation. A GIS-based extrapolation of our site data suggests that a substantial amount (~40%) of total WSL peat C has accumulated since 2 ka, with much of this accumulation south of 60°N. The large peatlands in the southern WSL may be an important component of the Eurasian terrestrial C sink, and future warming could result in a shift northward in long-term WSL C sequestration.
Resumo:
Suppressors of cytokine signaling (SOCS) proteins are a family of proteins that are able to act in a classic negative feedback loop to regulate cytokine signal transduction. The regulation of the immune response by SOCS proteins may contribute to persistent infection or even a fatal outcome. In this study, we have investigated the induction of SOCS 1-3 after peripheral infection with West Nile virus (WNV) or tick-borne encephalitis virus (TBEV) in the murine model. We have shown that the cytokine response after infection of mice with WNV or TBEV induces an upregulation in the brain of mRNA transcripts for SOCS 1 and SOCS 3, but not SOCS 2. We hypothesize that SOCS proteins may play a role in limiting cytokine responses in the brain as a neuroprotective mechanism, which may actually enhance the ability of neuroinvasive viruses such as WNV and TBEV to spread and cause disease.
Resumo:
The seventh-century Patrician documents in the Book of Armagh, and other early sources such as Bethu Phátraic, contain references to the toponym Macha, which has been identified by the Dictionary of the Irish Language with either the ecclesiastical centre of Ard Macha or the ‘royal seat’ of Emain Macha. This article examines the evidence for the name in the sources and illustrates that Macha applies primarily to the plain in which both Ard Macha and Emain Macha are located. It is to be identified with Mag Macha ‘the plain of Macha’, familiar to us from the Dindshenchus, and further evidence of the organic potential of a given toponym is witnessed in later sources where the plain is referred to as Mag/Machaire na hE(a)mna ‘the plain of Emain’ and Machaire Aird/Arda Macha ‘the plain of Armagh’. The extent of Macha is difficult to establish with certainty, but it seems very likely that it stretched north to the River Blackwater as well as south towards Slíab Fúait.
Resumo:
This article examines two metatheatrical plays written by playwrights from the north of Ireland that bookend the twentieth century. The first is Ulster Literary Theatre (ULT) playwright Gerald MacNamara’s parodic, “proto-Pirandellian”4 The Mist That Does Be on the Bog (1909), which satirizes the peasant aesthetic of the “Abbey play” of the Irish Revival.5 The second is Marie Jones’s international hit, Stones in His Pockets (1999), a “play-full,” postmodern deconstruction of the commodification of Irish culture in the era of the Celtic Tiger. Although separated by exactly ninety years, the two plays can be connected through their critiques of the cultural politics of nationalism and globalization during the periods of the Irish Revival and the Celtic Tiger, respectively. Moreover, both plays are distinguished by their dramaturgical form, as the political critique of each is corporeally embodied in metatheatrical performance.