Late holocene environments in Las Tablas de Daimiel (south central Iberian peninsula, Spain)

The use of a high resolution pollen record in combination with geochemical data from sediments composed mainly of layers of charophytes alternating with layers of vegetal remains plus some detrital beds permits the reconstruction of the environmental evolution of the last 3000 years in an inland wetland of the Mediterranean domain, thus introducing a new climatic dataset for the Late Holocene. Hydrological fluctuations, reflected in the relationship between emerged and aquatic vegetation and inorganic and organic C and N changes, can be related to aridity or humid phases, while relations among arboreal taxa (Quercus and Pinus) and Artemisia are used as temperature indicators. Five climatic periods have been identified: a Subatlantic Cold Period (<150 b.c.), cold and arid; the RomanWarm Period (150 b.c.–a.d. 270), warmer and wetter; the Dark Ages (a.d. 270–a.d. 950), colder and drier; the Medieval Warm Period (a.d. 950–a.d. 1400), warmer and wetter; and the Little Ice Age (>a.d. 1400) indicated by a cooling and drying trend. Despite the lack of any direct evidence of human action, there are some episodes related to deforestation during the Reconquista (Middle Ages) that mask the real climatic signal

Feasibility of quantification of the distribution of blood flow in the normal human fetal circulation using CMR:a cross-sectional study

BACKGROUND: We present the first phase contrast (PC) cardiovascular magnetic resonance (CMR) measurements of the distribution of blood flow in twelve late gestation human fetuses. These were obtained using a retrospective gating technique known as metric optimised gating (MOG). METHODS: A validation experiment was performed in five adult volunteers where conventional cardiac gating was compared with MOG. Linear regression and Bland Altman plots were used to compare MOG with the gold standard of conventional gating. Measurements using MOG were then made in twelve normal fetuses at a median gestational age of 37 weeks (range 30–39 weeks). Flow was measured in the major fetal vessels and indexed to the fetal weight. RESULTS: There was good correlation between the conventional gated and MOG measurements in the adult validation experiment (R=0.96). Mean flows in ml/min/kg with standard deviations in the major fetal vessels were as follows: combined ventricular output (CVO) 540±101, main pulmonary artery (MPA) 327±68, ascending aorta (AAo) 198±38, superior vena cava (SVC) 147±46, ductus arteriosus (DA) 220±39,pulmonary blood flow (PBF) 106±59,descending aorta (DAo) 273±85, umbilical vein (UV) 160±62, foramen ovale (FO)107±54. Results expressed as mean percentages of the CVO with standard deviations were as follows: MPA 60±4, AAo37±4, SVC 28±7, DA 41±8, PBF 19±10, DAo50±12, UV 30±9, FO 21±12. CONCLUSION: This study demonstrates how PC CMR with MOG is a feasible technique for measuring the distribution of the normal human fetal circulation in late pregnancy. Our preliminary results are in keeping with findings from previous experimental work in fetal lambs