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At the Last Glacial Maximum (LGM) about 21000 years ago (21 ka BP), the overall mass balance of the Laurentide and Eurasian ice sheets should have been close to zero, since their rate of change of total ice volume was approximately zero at that time. The surface mass balance should have been zero or positive to balance any iceberg/iceshelf discharge and basal melting, but could not have been strongly negative. In principle this can be tested by global climate model (GCM) simulations with prescribed ice-sheet extents and topography.

We describe results from a suite of 21 ka BP simulations using a new GCM (GENESIS version 2.0.a), with sea-surface temperatures (SSTs) prescribed from GLIMAP (1981) and predicted by a mixed-layer ocean model, and with ice sheets prescribed from both the ICE-4G (Peltier, 1994) and CLIMAP (1981) reconstructions. This GCM is well suited for ice-sheet mass-balance studies because (i) the surface can be represented at a finer resolution than the atmospheric GCM, (ii) an elevation correction accounts for spectral distortions of the atmospheric GCM topography, (iii) a simple post-processing correction for the refreezing of meltwater is applied, and (iv) the model's precipitation and mass balances for present-day Greenland and Antarctica are realistic. However, for all reasonable combinations of SSTs and ice-sheet configurations, the predicted annual surface mass balances of the LGM Laurentide and Eurasian ice sheets are implausibly negative. Possible reasons for this discrepancy are discussed, including increased ice-age aerosols, higher CLIMAP-like ice-sheet profiles in the few thousand years preceding the LGM, and a surface of the southern Laurentide just before the LGM to produce fleetingly the ICE-4G profile at 21 ka BP.

Studies examining productive syntax have used varying elicitation methods and have tended to focus on either young children or adolescents/adults, so we lack an account of syntactic development throughout middle childhood. We describe here the results of an analysis of clause complexity in narratives produced by 354 speakers aged from four years to adulthood using the Expressive, Receptive, and Recall of Narrative Instrument (ERRNI). We show that the number of clauses per utterance increased steadily through this age range. However, the distribution of clause types depended on which of two stories was narrated, even though both stories were designed to have a similar story structure. In addition, clausal complexity was remarkably similar regardless of whether the speaker described a narrative from pictures, or whether the same narrative was recalled from memory. Finally, our findings with the youngest children showed that the task of generating a narrative from pictures may underestimate syntactic competence in those aged below five years.

The idea that the churches became agents of empire through their missionary activity is very popular, but it is too simple. Established Churches, such as those of England and Scotland, could certainly be used by government, usually willingly; so could the Roman Catholic Church in the empires of other countries. But the position of the smaller churches, usually with no settler community behind them, was different. This study examines the effects of the Chilembwe Rising of 1915 on the British Churches of Christ mission in Nyasaland (modern Malawi). What is empire? The Colonial Office and the local administration might view a situation in different ways. Their decisions could thus divide native Christians from the UK, and even cause division in the UK church itself, as well as strengthening divisions on the mission field between different churches. Thus, even in the churches, imperial actions could foster the African desire for independence of empire.

What is known about the topic?

Children’s pain in the emergency department (ED) continues to be under-recognized and sub-optimally managed.

What did this study ask?

We sought to evaluate the frequency of caregiver/child acceptance of analgesia offered in the ED.

What did this study find?

Of the 743 children who presented to the ED with a painful condition, 408 (54.9%) were offered analgesia. If offered in the ED, analgesia was accepted by 91% (373/408) of the caregivers/children.

Why does this study matter to clinicians?

This study suggests that caregiver/child refusal of analgesia is a not a major barrier to optimal pain management and highlights the importance of ED personnel in encouraging adequate analgesia.

The target site of glyphosate [N-(phosphonomethyl)glycine] inhibition in plants and bacteria is 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase. Our strategy for developing glyphosate-resistant crops has been to genetically engineer plants with a gene that codes for EPSP synthase with low sensitivity in glyphosate. We cloned such a gene from the aroA locus of a glyphosate-resistant mutagenized strain of Salmonella typhimurium. The enzyme encoded by this gene has a single amino acid change resulting in lower affinity for glyphosate and higher affinity for substrates than either plant or wild-type bacterial counterpart. A chimaeric gene containing the mutant aroA gene behind the octopine synthase promoter was constructed and integrated into Agrobacterium T-DNA vectors. Analysis of gall tissue from Brassica campestris L. (turnip rape) infected with A. tumefaciens K12 containing this chimaera showed mRNA and protein expressed from the bacterial gene; 50% of the total EPSP synthase activity present had kinetic properties of the mutant bacterial enzyme. Tobacco (Nicotiana tabacum L. ‘Xanthi′) plants have been regenerated from cocultivation with A. rhizogenes containing the same construct; analysis indicates expression of the gene and enhanced tolerance to glyphosate.

Most dynamic ice-sheet studies currently use either empirically based parameterizations or simple energy-balance climate models for the surface mass-balance forcing. If three-dimensional global climate models (GCMs) could be used instead, they would greatly improve the potential realism of coupled climate ice-sheet simulations. However, there are two serious problems in simulating realistic mass balances on ice sheets from GCM simulations: (i) dynamic ice-sheet models and the underlying bedrock topography need horizontal resolution of 50–100 km or less, but the finest practical resolution of atmospheric GCMs is currently ˜250 km, and (ii) GCM surface physics usually neglects the local refreezing of meltwater on ice sheets.

Two techniques are described that address these problems: an elevation correction applied to the atmospheric GCM fields interpolated to the ice-sheet grid, and a refreezing correction involving the annual totals of snowfall, rainfall and local melt at each grid-point. As an example of their use, we have used the GENESIS version 2 GCM at 3.75° × 3.75° resolution to simulate the climate at the end of the last interglaciation at ˜116 000 years ago. The atmospheric climate is then used to drive a standard two-dimensional dynamic ice-sheet model for 10 000 years on a 0.5° × 0.5° grid spanning northern North America. The model successfully predicts ice-sheet initiation over the Baffin Island highlands and the Canadian Archipelago, but at a slower rate than observed. A large ice sheet nucleates and grows rapidly over the northwestern Rockies, in conflict with geologic evidence. Possible reasons for these discrepancies are discussed.

The Permian is regarded as one of the most crucial intervals during echinoid evolution because crown group echinoids are first widely known from the Permian. New faunas provide important information regarding the diversity of echinoids during this significant interval as well as the morphological characterization of the earliest crown group and latest stem group echinoids. A new fauna from the Capitanian Lamar Member of the Bell Canyon Formation in the Guadalupe Mountains of West Texas comprises at least three new taxa, including Eotiaris guadalupensis Thompson n. sp. an indeterminate archaeocidarid, and Pronechinus? sp. All specimens represented are silicified and known from disarticulated or semiarticulated interambulacral and ambulacral plates and spines. This assemblage is one of the most diverse echinoid assemblages known from the Permian and, as such, informs the paleoecological setting in which the earliest crown group echinoids lived. This new fauna indicates that crown group echinoids occupied the same environments as stem group echinoids of the Archaeocidaridae and Proterocidaridae. Furthermore, the echinoids described herein begin to elucidate the order of character transitions that likely took place between stem group and crown group echinoids. At least one of the morphological innovations once thought to be characteristic of early crown group echinoids, crenulate tubercles, was in fact widespread in a number of stem group taxa from the Permian as well. Crenulate tubercles are reported from two taxa, and putative cidaroid style U-shaped teeth are present in the fauna. The presence of crenulate tubercles in the archaeocidarid indicates that crenulate tubercles were present in stem group echinoids, and thus the evolution of this character likely preceded the evolution of many of the synapomorphies that define the echinoid crown group.

A stability equation is derived for a model glacier of initially uniform thickness and of infinite extent transverse to the primary flow flowing without slip down an inclined plane. A stress-dependent power-law viscosity is wholly incorporated into the equations of motion. Stability of the glacier is tested against long-wavelength surface perturbations. Results for this initial formulation indicate that the glacier is stable against infinitesimal amplitude surface perturbations, although for certain variations of model parameters, the decay-rate of the disturbance becomes very slow, approaching neutral stability. Results are presented in terms of decay-rate magnitudes over a large range of perturbation wavelengths for many model glaciers in which bed slope, ice thickness, and ice rheology parameters are varied. For all models, the maximum decay-rate of the perturbation occurs at disturbance wavelengths of roughly three to six times the glacier thickness. Infinite-wavelength perturbations are found to be only neutrally stable. Long-wavelength perturbations propagate at a faster rate down-glacier than do the intermediate- or shorter-wavelength ones which tend to remain fixed on the glacier surface andride down-glacier with the primary flow as they decay.

Geodetic surveying and ground-based radar profiling were used to determine geometry and surface motion of the ice sheet on the Dyer Plateau, Antarctica, in the vicinity of an ice-core site on a local dome. Vertical strain measurements in the core hole constrain the depth profile of vertical velocity. These geophysical measurements are used to analyze the profiles of density and annual layer thickness measured on the ice core to estimate the current mass balance of the ice column and the past history of accumulation rate. Consideration of horizontal and vertical mass-flow divergence shows that the profiles of density and vertical velocity are not fully consistent with steady state. Mean density of the firn layer appears to be increasing, which leads to the deduction of a small rate of mass increase (≈ 0.02 m a− 1 ice-equivalent thickness). Over the last 200a there has been a gradual increase in accumulation rate from about 0.46 m a− 1 to 0.54 m a− 1 ice-equivalent thickness in recent time.

Asynchronous coupling schemes between ice sheet and atmospheric forcing models are evaluated for use in long-term ice-age simulations. In these schemes the ice sheet and atmospheric forcing are run together for short synchronous periods (T s), alternating with longer asynchronous periods (T A) during which the ice sheet is run with atmospheric information extrapolated from the previous synchronous period(s). Two simple ice-sheet models are used that predict ice thickness as a function of latitude, and the atmosphere is represented by a prescribed pattern of net annual accumulation minus ablation. The pattern is shifted vertically to represent long-term orbital variations, stochastic inter-annual weather variability and ice-sheet albedo feedback.

Several asynchronous schemes are evaluated by comparing results with those from fully synchronous runs. The best overall results are obtained using a scheme in which the forcing during each asynchronous period is linearly extrapolated from its means in the previous two synchronous periods. Differences from the synchronous results are caused primarily by poor sampling of the stochastic forcing component, which exaggerates the stochastic ice-sheet fluctuations. We examine how these errors depend on T s and T A, and outline implications for GCM ice-age simulations.