Carbon Isotope Constraints on the Deglacial CO2 Rise from Ice Cores

The stable carbon isotope ratio of atmospheric CO2 (d13Catm) is a key parameter in deciphering past carbon cycle changes. Here we present d13Catm data for the past 24,000 years derived from three independent records from two Antarctic ice cores. We conclude that a pronounced 0.3 per mil decrease in d13Catm during the early deglaciation can be best explained by upwelling of old, carbon-enriched waters in the Southern Ocean. Later in the deglaciation, regrowth of the terrestrial biosphere, changes in sea surface temperature, and ocean circulation governed the d13Catm evolution. During the Last Glacial Maximum, d13Catm and atmospheric CO2 concentration were essentially constant, which suggests that the carbon cycle was in dynamic equilibrium and that the net transfer of carbon to the deep ocean had occurred before then

A systematic review and meta-analysis of selected motor learning principles in physiotherapy and medical education

Background Learning of procedural skills is an essential component in the education of future health professionals. There is little evidence on how procedural skills are best learnt and practiced in education. There is a need for educators to know what specific interventions could be used to increase learning of these skills. However, there is growing evidence from rehabilitation science, sport science and psychology that learning can be promoted with the application of motor learning principles. The aim of this review was to systematically evaluate the evidence for selected motor learning principles in physiotherapy and medical education. The selected principles were: whole or part practice, random or blocked practice, mental or no additional mental practice and terminal or concurrent feedback. Methods CINAHL, Cochrane Central, Embase, Eric and Medline were systematically searched for eligible studies using pre-defined keywords. Included studies were evaluated on their risk of bias with the Cochrane Collaboration's risk of bias tool. Results The search resulted in 740 records, following screening for relevance 15 randomised controlled trials including 695 participants were included in this systematic review. Most procedural skills in this review related to surgical procedures. Mental practice significantly improved performance on a post-acquisition test (SMD: 0.43, 95 % CI 0.01 to 0.85). Terminal feedback significantly improved learning on a transfer test (SMD: 0.94, 95 % CI 0.18 to 1.70). There were indications that whole practice had some advantages over part practice and random practice was superior to blocked practice on post-acquisition tests. All studies were evaluated as having a high risk of bias. Next to a possible performance bias in all included studies the method of sequence generation was often poorly reported. Conclusions There is some evidence to recommend the use of mental practice for procedural learning in medical education. There is limited evidence to conclude that terminal feedback is more effective than concurrent feedback on a transfer test. For the remaining parameters that were reviewed there was insufficient evidence to make definitive recommendations.Britain has a serious shortage of nurses, as well as problems in recruiting and retaining them It is not simply that there are too few nurses; some key skills shortages also exist, with increasing demand for more qualified staff in some areas Much better planning of the workforce is required, and this needs to be more integrated with the planning for other groups in healthcare A change in the pay system may help, but the creation of better work environments may be part of the solution The rapid pace of change in the nursing profession has produced a challenge that the NHS needs to addresssch_phy16pub4254pub1

Multi vegetation model evaluation of the Green Sahara climate regime

During the Quaternary, the Sahara desert was periodically colonized by vegetation, likely because of orbitally induced rainfall increases. However, the estimated hydrological change is not reproduced in climate model simulations, undermining confidence in projections of future rainfall. We evaluated the relationship between the qualitative information on past vegetation coverage and climate for the mid-Holocene using three different dynamic vegetation models. Compared with two available vegetation reconstructions, the models require 500–800 mm of rainfall over 20°–25°N, which is significantly larger than inferred from pollen but largely in agreement with more recent leaf wax biomarker reconstructions. The magnitude of the response also suggests that required rainfall regime of the early to middle Holocene is far from being correctly represented in general circulation models. However, intermodel differences related to moisture stress parameterizations, biases in simulated present-day vegetation, and uncertainties about paleosoil distributions introduce uncertainties, and these are also relevant to Earth system model simulations of African humid periods

Process-Tracing as a Tool to Analyse Discretion

status: publishe