Tropical Andean climate variations since the last deglaciation.

Global warming during the Last Glacial Termination was interrupted by millennial-scale cool intervals such as the Younger Dryas and the Antarctic Cold Reversal (ACR). Although these events are well characterized at high latitudes, their impacts at low latitudes are less well known. We present high-resolution temperature and hydroclimate records from the tropical Andes spanning the past ~16,800 y using organic geochemical proxies applied to a sediment core from Laguna Llaviucu, Ecuador. Our hydroclimate record aligns with records from the western Amazon and eastern and central Andes and indicates a dominant long-term influence of changing austral summer insolation on the intensity of the South American Summer Monsoon. Our temperature record indicates a ~4 °C warming during the glacial termination, stable temperatures in the early to mid-Holocene, and slight, gradual warming since ~6,000 y ago. Importantly, we observe a ~1.5 °C cold reversal coincident with the ACR. These data document a temperature change pattern during the deglaciation in the tropical Andes that resembles temperatures at high southern latitudes, which are thought to be controlled by radiative forcing from atmospheric greenhouse gases and changes in ocean heat transport by the Atlantic meridional overturning circulation.

In Vivo-Like Growth Patterns of Multiple Types of Tumors in Gelfoam® Histoculture.

Diverse human tumors obtained directly from surgery or biopsy can grow at high frequency in 3-dimensional Gelfoam® histoculture for long periods of time and still maintain many of their in vivo properties. The in vivo properties maintained in vitro include 3-dimensional growth; maintenance of tissue organization and structure, such as changes associated with oncogenic transformation; retention of differentiated function; tumorigenicity; and growth of multiple types of cells from a single tumor.