Relative sea-level change, Kjove Land, Scoresby Sund, East Greenland: Implications for seasonality in Younger Dryas time

The age of the Milne Land Stade (MLS) moraines in the Scoresby Sund region of East Greenland is key for testing the hypothesis that strong seasonality marked abrupt cooling events, such as the Younger Dryas, registered in Greenland ice cores. The relevant chronology is based on 69 radiocarbon dates of shells from raised beaches and deltas related to marine inundation and isostatic rebound that accompanied glacier retreat from the moraines. Taken together, these dates form the basis for a relative sea-level curve that shows very high rates of emergence typical of recently deglaciated regions. Upward extrapolation of this curve suggests that the marine limit (134 m a.s.l.) dates to about 12,400 cal yr B.P. The shorelines that mark the marine limit lie within areas that were ice-covered when the glaciers were at the outer limit of the MLS advance; hence, the moraines that form the outer limit must antedate 12,400 cal yr B.P. and probably are from earliest Younger Dryas or Allerød time. At Holger Danskes Briller, an inner moraine grades to a massive ice-contact delta, now at 101 m a.s.l., which is dated to 11,000–11,300 cal yr B.P. The age of the outer MLS moraines, along with constraints on the maximum possible Younger Dryas ice extent and snowline lowering are consistent with the idea that East Greenland climate experienced strong seasonality during Younger Dryas time

Retreat of the Cordillera Darwin icefield during the Termination I

Durante la última glaciación, el campo de hielo de la Cordillera Darwin se expandió hacia el norte en dirección al Estrecho de Magallanes; hacia el este, a través de la Isla Grande de Tierra del Fuego y del Canal Beagle; y hacia el sur y oeste, a través de las numerosas islas del sur de Chile. La deglaciación comenzó hace ~ 18 ka, durante el Termination I. Los glaciares alpinos en los Andes Fueguinos probablemente también se retiraron en ese momento. Las edades de radiocarbono de las regiones interiores de la Cordillera Darwin sugieren que el hielo en algunas localidades se había retirado cerca de su límite actual ya hacia ~ 16.5 ka. La causa más probable de este rápido retroceso del hielo fue el aumento de las temperaturas atmosféricas al inicio del periodo Termination I.During the last glaciation, the Cordillera Darwin icefield expanded northward toward the Straits of Magellan, eastward across Isla Grande de Tierra del Fuego and through Canal Beagle, and south and west across the numerous islands of southernmost Chile. Deglaciation commenced at ~18 ka during Termination I. Alpine glaciers in the Fuegian Andes also likely retreated at that time. Radiocarbon ages from the interior regions of Cordillera Darwin suggest ice in at least some locations had retreated close to its present-day limit as early as ~16.5 ka. The most likely cause for such rapid ice retreat was rising atmospheric temperatures at the start of Termination I

Toward the development of an antidisease, transmission-blocking intranasal vaccine for group A streptococcus

Infection with group A streptococcus (GAS) may result in a number of clinical conditions, including the potentially life-threatening postinfectious sequelae of rheumatic fever and rheumatic heart disease. As part of the search for a vaccine to prevent GAS infection, a conformationally constrained and minimally conserved peptide, J14, from the M protein of GAS has been defined. In the present study, J14 was formulated with bacterial outer membrane proteins (proteosomes) and then intranasally administered to outbred mice without additional adjuvant. Such immunization led to high titers of J14-specific serum immunoglobulin (Ig) G and mucosal IgA. After upper respiratory tract GAS challenge, immunized mice demonstrated increased survival and reduced GAS colonization of the throat