Greenland was nearly ice-free for extended periods during the Pleistocene.

The Greenland Ice Sheet (GIS) contains the equivalent of 7.4 metres of global sea-level rise. Its stability in our warming climate is therefore a pressing concern. However, the sparse proxy evidence of the palaeo-stability of the GIS means that its history is controversial (compare refs 2 and 3 to ref. 4). Here we show that Greenland was deglaciated for extended periods during the Pleistocene epoch (from 2.6 million years ago to 11,700 years ago), based on new measurements of cosmic-ray-produced beryllium and aluminium isotopes (10Be and 26Al) in a bedrock core from beneath an ice core near the GIS summit. Models indicate that when this bedrock site is ice-free, any remaining ice is concentrated in the eastern Greenland highlands and the GIS is reduced to less than ten per cent of its current volume. Our results narrow the spectrum of possible GIS histories: the longest period of stability of the present ice sheet that is consistent with the measurements is 1.1 million years, assuming that this was preceded by more than 280,000 years of ice-free conditions. Other scenarios, in which Greenland was ice-free during any or all Pleistocene interglacials, may be more realistic. Our observations are incompatible with most existing model simulations that present a continuously existing Pleistocene GIS. Future simulations of the GIS should take into account that Greenland was nearly ice-free for extended periods under Pleistocene climate forcing.

Glacier extent during the Younger Dryas and 8.2-ka event on Baffin Island, Arctic Canada.

Greenland ice cores reveal that mean annual temperatures during the Younger Dryas (YD) cold interval--about 12.9 to 11.7 thousand years ago (ka)--and the ~150-year-long cold reversal that occurred 8.2 thousand years ago were ~15° and 3° to 4°C colder than today, respectively. Reconstructing ice-sheet response to these climate perturbations can help evaluate ice-sheet sensitivity to climate change. Here, we report the widespread advance of Laurentide Ice Sheet outlet glaciers and independent mountain glaciers on Baffin Island, Arctic Canada, in response to the 8.2-ka event and show that mountain glaciers during the 8.2-ka event were larger than their YD predecessors. In contrast to the wintertime bias of YD cooling, we suggest that cooling during the 8.2-ka event was more evenly distributed across the seasons.

Glacier retreat in New Zealand during the Younger Dryas stadial.

Millennial-scale cold reversals in the high latitudes of both hemispheres interrupted the last transition from full glacial to interglacial climate conditions. The presence of the Younger Dryas stadial (approximately 12.9 to approximately 11.7 kyr ago) is established throughout much of the Northern Hemisphere, but the global timing, nature and extent of the event are not well established. Evidence in mid to low latitudes of the Southern Hemisphere, in particular, has remained perplexing. The debate has in part focused on the behaviour of mountain glaciers in New Zealand, where previous research has found equivocal evidence for the precise timing of increased or reduced ice extent. The interhemispheric behaviour of the climate system during the Younger Dryas thus remains an open question, fundamentally limiting our ability to formulate realistic models of global climate dynamics for this time period. Here we show that New Zealand's glaciers retreated after approximately 13 kyr bp, at the onset of the Younger Dryas, and in general over the subsequent approximately 1.5-kyr period. Our evidence is based on detailed landform mapping, a high-precision (10)Be chronology and reconstruction of former ice extents and snow lines from well-preserved cirque moraines. Our late-glacial glacier chronology matches climatic trends in Antarctica, Southern Ocean behaviour and variations in atmospheric CO(2). The evidence points to a distinct warming of the southern mid-latitude atmosphere during the Younger Dryas and a close coupling between New Zealand's cryosphere and southern high-latitude climate. These findings support the hypothesis that extensive winter sea ice and curtailed meridional ocean overturning in the North Atlantic led to a strong interhemispheric thermal gradient during late-glacial times, in turn leading to increased upwelling and CO(2) release from the Southern Ocean, thereby triggering Southern Hemisphere warming during the northern Younger Dryas.

High-frequency Holocene glacier fluctuations in New Zealand differ from the northern signature.

Understanding the timings of interhemispheric climate changes during the Holocene, along with their causes, remains a major problem of climate science. Here, we present a high-resolution 10Be chronology of glacier fluctuations in New Zealand's Southern Alps over the past 7000 years, including at least five events during the last millennium. The extents of glacier advances decreased from the middle to the late Holocene, in contrast with the Northern Hemisphere pattern. Several glacier advances occurred in New Zealand during classic northern warm periods. These findings point to the importance of regional driving and/or amplifying mechanisms. We suggest that atmospheric circulation changes in the southwest Pacific were one important factor in forcing high-frequency Holocene glacier fluctuations in New Zealand.

Comparison of coronary risk factors and quality of life in coronary artery disease patients with versus without diabetes mellitus.

It is unclear whether patients with coronary artery disease (CAD) and diabetes mellitus (DM) can make comprehensive lifestyle changes that produce similar changes in coronary risk factors and quality of life compared with patients with CAD and without DM. We examined medical characteristics, lifestyle, and quality of life by diabetic status and gender in the Multicenter Lifestyle Demonstration Project (MLDP), a study of 440 nonsmoking patients with CAD (347 men, 55 with DM; 15.9%; 93 women, 36 with DM; 38.7%). Patients met in groups to improve lifestyle (plant-based, low-fat diet; exercise; stress management) for 1 year. Follow-ups were conducted at 3 and 12 months. At baseline, body mass and systolic blood pressure were significantly higher among patients with DM. Men with DM had a worse medical history (e.g., hypertension, hyperlipidemia, and family history of CAD) than did those without DM. Patients with DM, especially women, reported poorer quality of life than did patients without DM. The 2 groups of patients were able to adhere to the recommended lifestyle, as demonstrated by significant improvements in weight (mean -5 kg), body fat, low-density lipoprotein cholesterol, exercise capacity, and quality of life. No significant changes in triglycerides and high-density lipoprotein cholesterol were noted. By the end of 12 months, improvements in glucose-lowering medications (i.e., discontinuation or a change from insulin to oral hypoglycemic agents) were noted for 19.8% (n = 18) of patients with DM. In conclusion, patients with CAD and DM are able to follow a comprehensive lifestyle change program and show similar improvements in coronary risk factors and quality of life as those without DM.

Model for energy oscillations in cells.

Rapid periodic pulses have been observed in yeast cell walls and these pulsations must be accompanied by coherent oscillations of energy. Such energy oscillations are likely to be a common feature in cells and we explore other consequences, either known or unknown, that may originate from chemical oscillations of small amplitude. We do not consider specific mechanisms for the energy oscillations, but here we accept their existence as a fact following from the yeast experiments. Chemical oscillators are treated as generic quantum oscillators and this model predicts that observed frequencies should have a simple volume-dependence where smaller cells exhibit higher frequencies than their larger counterparts. An extension to multicellular organisms then affords a derivation of the celebrated Kleiber law that evaluates both the numerical coefficient and the 34 exponent of mass. Calculations of activation energies and efficiencies at experimental temperatures follow. Finally, the model is applied to derive established expressions for blood flow and pulse rate. We conclude that the model reflects some common metabolic process insofar as it agrees with diverse quantitative findings while using minimal input data and without introducing free parameters.

Early local last glacial maximum in the tropical Andes.

The local last glacial maximum in the tropical Andes was earlier and less extensive than previously thought, based on 106 cosmogenic ages (from beryllium-10 dating) from moraines in Peru and Bolivia. Glaciers reached their greatest extent in the last glacial cycle approximately 34,000 years before the present and were retreating by approximately 21,000 years before the present, implying that tropical controls on ice volumes were asynchronous with those in the Northern Hemisphere. Our estimates of snowline depression reflect about half the temperature change indicated by previous widely cited figures, which helps resolve the discrepancy between estimates of terrestrial and marine temperature depression during the last glacial cycle.

Measurement of beryllium in biological samples by accelerator mass spectrometry: applications for studying chronic beryllium disease.

A method using accelerator mass spectrometry (AMS) has been developed for quantifying attomoles of beryllium (Be) in biological samples. This method provides the sensitivity to trace Be in biological samples at very low doses with the purpose of identifying the molecular targets involved in chronic beryllium disease. Proof of the method was tested by administering 0.001, 0.05, 0.5, and 5.0 microg of 9Be and 10Be by intraperitoneal injection to male mice and removing the spleen, liver, femurs, blood, lungs, and kidneys after 24 h of exposure. These samples were prepared for AMS analysis by tissue digestion in nitric acid, followed by further organic oxidation with hydrogen peroxide and ammonium persulfate and, last, precipitation of Be with ammonium hydroxide and conversion to beryllium oxide at 800 degrees C. The 10Be/9Be ratio of the extracted beryllium oxide was measured by AMS, and Be in the original sample was calculated. Results indicate that Be levels were dose-dependent in all tissues and the highest levels were measured in the spleen and liver. The measured 10Be/9Be ratios spanned 4 orders of magnitude, from 10(-10) to 10(-14), with a detection limit of 3.0 x 10(-14), which is equivalent to 0.8 amol of 10Be. These results show that routine quantification of nanogram levels of Be in tissues is possible and that AMS is a sensitive method that can be used in biological studies to understand the molecular dosimetry of Be and mechanisms of toxicity.

Rapid late Pleistocene incision of Atlantic passive-margin river gorges.

The direct and secondary effects of rapidly changing climate caused large rivers draining the Atlantic passive margin to incise quickly into bedrock beginning about 35,000 years ago. Measured in samples from bedrock fluvial terraces, 10-beryllium shows that both the Susquehanna and Potomac Rivers incised 10- to 20-meter-deep gorges along steep, convex lower reaches during the last glacial cycle. This short-lived pulse of unusually rapid down-cutting ended by 13,000 to 14,000 years ago. The timing and rate of downcutting are similar on the glaciated Susquehanna and unglaciated Potomac Rivers, indicating that regional changes, not simply glacial meltwater, initiated incision.

Spirituality and choice of health care practitioner.

BACKGROUND: Patients who include a complementary and alternative medicine (CAM) practitioner in their health care represent a small percentage of the population identified as CAM users. Their choice may be motivated by intangible personality or worldview characteristics. OBJECTIVE: A prospective study was designed to determine if a patient's choice of conventional or alternative health care practitioner was related to total score on an instrument for scaling psychospiritual characteristics. DESIGN: A sequential convenience sample of patients attending five different health care practices in New England. SETTING: A family practitioner (FP) who uses CAM. (1) A FP clearly not identified with CAM. (3) A chiropractor. (4) A naturopath, and (5) A homeopath. OUTCOME MEASURES: Total scores on the Spiritual Involvement and Beliefs Scale (SIBS), plus item scores of five separate questions and two factors. RESULTS: With 210 respondents, SIBS scores in Practice 2 were significantly lower than in practice 1 (p = 0.004), 3 (p = 0.001), 4 (p = 0.018), and 5 (p = 0.02). This pattern remained over the five question scores and two factors. CONCLUSION: Patients who chose a physician associated with CAM, or an alternative practitioner (chiropractor, naturopath, or homeopath) for their direct health care scored higher on a psychospiritual testing instrument (SIBS) than those who chose a conventional physician.

Improvement in medical risk factors and quality of life in women and men with coronary artery disease in the Multicenter Lifestyle Demonstration Project.

This study examined medical and psychosocial characteristics of 440 patients (mean age 58 years, 21% women) with coronary artery disease at baseline and at 3-month and 12-month follow-ups. All patients were participants in the Multicenter Lifestyle Demonstration Project, aimed at improving diet (low fat, whole foods, plant-based), exercise, stress management, and social support. Spousal participation was encouraged. Both genders evidenced significant improvements in their diet, exercise, and stress management practices, which they maintained over the course of the study. Both women and men also showed significant medical (e.g., plasma lipids, blood pressure, body weight, exercise capacity) and psychosocial (e.g., quality of life) improvement. Despite their worse medical, psychosocial, and sociodemographic status at baseline, women's improvement was similar to that of men's. These results demonstrate that a multi-component lifestyle change program focusing on diet, exercise, stress management, and social support can be successfully implemented at hospitals in diverse regions of the United States. Furthermore, this program may be particularly beneficial for women with coronary artery disease who generally have higher mortality and morbidity than men after a heart attack, angioplasty, or bypass surgery.