How stable are 20th century calibration models? A high-resolution summer temperature reconstruction for the eastern Swiss Alps back to A.D. 1580 derived from proglacial varved sediments

We found a significant positive correlation between local summer air temperature (May-September) and the annual sediment mass accumulation rate (MAR) in Lake Silvaplana (46°N, 9°E, 1800 m a.s.l.) during the twentieth century (r = 0.69, p < 0.001 for decadal smoothed series). Sediment trap data (2001-2005) confirm this relation with exceptionally high particle yields during the hottest summer of the last 140 years in 2003. On this base we developed a decadal-scale summer temperature reconstruction back to AD 1580. Surprisingly, the comparison of our reconstruction with two other independent regional summer temperature reconstructions (based on tree-rings and documentary data) revealed a significant negative correlation for the pre-1900 data (ie, late ‘Little Ice Age’). This demonstrates that the correlation between MAR and summer temperature is not stable in time and the actualistic principle does not apply in this case. We suggest that different climatic regimes (modern/‘Little Ice Age’) lead to changing state conditions in the catchment and thus to considerably different sediment transport mechanisms. Therefore, we calibrated our MAR data with gridded early instrumental temperature series from AD 1760-1880 (r = -0.48, p < 0.01 for decadal smoothed series) to properly reconstruct the late LIA climatic conditions. We found exceptionally low temperatures between AD 1580 and 1610 (0.75°C below twentieth-century mean) and during the late Maunder Minimum from AD 1680 to 1710 (0.5°C below twentieth-century mean). In general, summer temperatures did not experience major negative departures from the twentieth-century mean during the late ‘Little Ice Age’. This compares well with the two existing independent regional reconstructions suggesting that the LIA in the Alps was mainly a phenomenon of the cold season.

Percutaneous coronary intervention for stable coronary artery disease

Patients with significant coronary artery stenoses are at increased risk of future cardiac events. However, in the absence of acute coronary syndrome or recent myocardial infarction and residual ischemia, elective percutaneous coronary intervention has not been shown to improve prognosis. Possible explanations for this might be the limited follow-up time adopted by most randomized trials comparing percutaneous coronary intervention with medical therapy, limited number of patients with proven ischemia enrolled in these trials, and adoption of complex, elaborate techniques that have not proved their usefulness. Published evidence identifies certain indications for percutaneous coronary intervention in patients with stable coronary lesions: demonstration of significant inducible ischemia, particularly in the context of a recent myocardial infarction; detection of unequivocally reduced fractional flow reserve; and specific angiographic features of coronary stenoses. Operators should take into account long-term consequences of adopted techniques rather than immediate angiographic results. We review existing evidence and provide our recommendations in this setting.

Relation of morning serum cortisol to prothrombotic activity in women with stable coronary artery disease

BACKGROUND: Increased circulating cortisol levels have been associated with severity of atherosclerosis. Low-grade systemic thrombogenicity plays a major role in the initiation and progression of coronary disease. We hypothesized a direct relationship between cortisol and hemostasis factors related to a prothrombotic state in coronary artery disease. METHODS: We measured morning serum cortisol and activated clotting factor VII, fibrinogen, von Willebrand factor antigen, and plasminogen activator inhibitor-1 activity in 285 women (56 +/- 7 years) between 3 and 6 months after an acute coronary event. To test whether the relationship between cortisol and hemostasis factors would be independent, statistical adjustment was made for demographic, biomedical, life style, and psychosocial variables. RESULTS: Higher serum cortisol levels predicted higher fibrinogen (beta = .17, P = .001) and higher von Willebrand factor (beta = .16, P = .008), all independently of covariates, including C-reactive protein, which was also an independent predictor of fibrinogen (beta = .20, P = .001) and von Willebrand factor (beta = .16, P = .004). Higher levels of vital exhaustion were associated with higher levels of activated clotting factor VII independently of covariates and depression (beta = .18, P = .045). Cortisol showed crude correlations with vital exhaustion (r = .14, P = .022) and with depression (r = .13, P = .043) but did not mediate the relationship between psychosocial variables and hemostatic factors. CONCLUSIONS: Morning serum cortisol showed a modest but independent association with prothrombotic activity in women with coronary artery disease suggesting that increased cortisol levels might contribute to atherosclerosis via eliciting a hypercoagulable state.

Geochemistry and Stable Isotopes of Surface Water and Groundwater in the Continental Pit in Butte, Montana, USA

The Continental porphyry Cu‐Mo mine, located 2 km east of the famous Berkeley Pit lake of Butte, Montana, contains two small lakes that vary in size depending on mining activity. In contrast to the acidic Berkeley Pit lake, the Continental Pit waters have near-neutral pH and relatively low metal concentrations. The main reason is geological: whereas the Berkeley Pit mined highly‐altered granite rich in pyrite with no neutralizing potential, the Continental Pit is mining weakly‐altered granite with lower pyrite concentrations and up to 1‐2% hydrothermal calcite. The purpose of this study was to gather and interpret information that bears on the chemistry of surface water and groundwater in the active Continental Pit. Pre‐existing chemistry data from sampling of the Continental Pit were compiled from the Montana Bureau of Mines and Geology and Montana Department of Environmental Quality records. In addition, in March of 2013, new water samples were collected from the mine’s main dewatering well, the Sarsfield well, and a nearby acidic seep (Pavilion Seep) and analyzed for trace metals and several stable isotopes, including dD and d18O of water, d13C of dissolved inorganic carbon, and d34S of dissolved sulfate. In December 2013, several soil samples were collected from the shore of the frozen pit lake and surrounding area. The soil samples were analyzed using X‐ray diffraction to determine mineral content. Based on Visual Minteq modeling, water in the Continental Pit lake is near equilibrium with a number of carbonate, sulfate, and molybdate minerals, including calcite, dolomite, rhodochrosite (MnCO3), brochantite (CuSO4·3Cu(OH)2), malachite (Cu2CO3(OH)2), hydrozincite (Zn5(CO3)2(OH)6), gypsum, and powellite (CaMoO4). The fact that these minerals are close to equilibrium suggests that they are present on the weathered mine walls and/or in the sediment of the surface water ponds. X‐Ray Diffraction (XRD) analysis of the pond “beach” sample failed to show any discrete metal‐bearing phases. One of the soil samples collected higher in the mine, near an area of active weathering of chalcocite‐rich ore, contained over 50% chalcanthite (CuSO4·5H2O). This water‐soluble copper salt is easily dissolved in water, and is probably a major source of copper to the pond and underlying groundwater system. However, concentrations of copper in the latter are probably controlled by other, less‐soluble minerals, such as brochantite or malachite. Although the acidity of the Pavilion Seep is high (~ 11 meq/L), the flow is much less than the Sarsfield Well at the current time. Thus, the pH, major and minor element chemistry in the Continental Pit lakes are buffered by calcite and other carbonate minerals. For the Continental Pit waters to become acidic, the influx of acidic seepage (e.g., Pavilion Seep) would need to increase substantially over its present volume.

Applications of Stable Isotope Ratio Analysis for Social Science Research

Stable Isotope Ratio Analysis (SIRA) is the measurement of variation in different isotopes of same elements in a material. This technique is well-established in the natural sciences and has been long part of the methodological arsenal in fields such as geology and biology. More recently this technique has begun to be utilized in the social sciences, moving from initial applications in anthropology to potential uses in geography, public health, forensic science, and others. This presentation will discuss the techniques behind SIRA, examples of current applications in the natural and social sciences, and potential avenues of future research.

Haemodynamic and arrhythmic effects of moderately cold (22 degrees C) water immersion and swimming in patients with stable coronary artery disease and heart failure

AIMS: Data on moderately cold water immersion and occurrence of arrhythmias in chronic heart failure (CHF) patients are scarce. METHODS AND RESULTS: We examined 22 male patients, 12 with CHF [mean age 59 years, ejection fraction (EF) 32%, NYHA class II] and 10 patients with stable coronary artery disease (CAD) without CHF (mean age 65 years, EF 52%). Haemodynamic effects of water immersion and swimming in warm (32 degrees C) and moderately cold (22 degrees C) water were measured using an inert gas rebreathing method. The occurrence of arrhythmias during water activities was compared with those measured during a 24 h ECG recording. Rate pressure product during water immersion up to the chest was significantly higher in moderately cold (P = 0.043 in CHF, P = 0.028 in CAD patients) compared with warm water, but not during swimming. Rate pressure product reached 14200 in CAD and 12 400 in CHF patients during swimming. Changes in cardiac index (increase by 5-15%) and oxygen consumption (increase up to 20%) were of similar magnitude in moderately cold and warm water. Premature ventricular contractions (PVCs) increased significantly in moderately cold water from 15 +/- 41 to 76 +/- 163 beats per 30 min in CHF (P = 0.013) but not in CAD patients (20 +/- 33 vs. 42 +/- 125 beats per 30 min, P = 0.480). No ventricular tachycardia was noted. CONCLUSION: Patients with compensated CHF tolerate water immersion and swimming in moderately cold water well. However, the increase in PVCs raises concerns about the potential danger of high-grade ventricular arrhythmias.

Stepped osteotomy of the trochanter for stable, anatomic refixation

Refixation of a trochanteric osteotomy carries a high complication rate. To enhance stability and facilitate anatomic reduction of the trochanteric fragment, we have introduced a stepped osteotomy. Between April 2006 and June 2007, we performed surgical hip dislocations using the modified trochanteric osteotomy combined with a relatively aggressive rehabilitation program. Full weightbearing was allowed at a mean of 42 days (range, 33-54 days). The minimum followup was 8 months (median, 13 months; range, 8-24 months). Postoperative radiographs were assessed prospectively for consolidation or the appearance of malreduction/nonunion/malunion of the osteotomy and heterotopic ossification. In 110 of 113 hips, the trochanteric osteotomy healed in the anatomic position. Two patients had a trochanteric delayed union with loss of anatomic position, and one additional patient underwent revision surgery for a pseudarthrosis and cranial migration of the trochanteric fragment. All three complications related to healing occurred in the first 60 patients when the step height was 3 to 4 mm. After increasing the step heights to 6 mm, we observed no healing complications. Despite more aggressive postoperative mobilization, the incidence of malunion or nonunion related to the new stepped osteotomy is low and approaches zero for steps of 6 mm. It is now our technique of choice.

Temporal patterns in lacustrine stable isotopes as evidence for climate change during the late glacial in the Southern European Alps

We investigated oxygen and carbon isotopes of bulk carbonate and of benthic freshwater ostracods (Candona candida) in a sediment core of Lago Piccolo di Avigliana that was previously analyzed for pollen and loss-on-ignition, in order to reconstruct environmental changes during the late glacial and early Holocene. The depth-age relationship of the sediment core was established using 14 AMS C-14 dates and the Laacher See Tephra. While stable isotopes of bulk carbonates may have been affected by detrital input and, therefore, only indirectly reflect climatic changes, isotopes measured on ostracod shells provide unambiguous evidence for major environmental changes. Oxygen isotope ratios of ostracod shells (delta O-18(C)) increased by similar to 6 parts per thousand at the onset of the Bolling (similar to 14,650 cal BP) and were similar to 2 parts per thousand lower during the Younger Dryas (similar to 12,850 to 11,650 cal BP), indicating a temporal pattern of climate changes similar to the North Atlantic region. However, in contrast to records in that region, delta O-18(C) gradually decreased during the early Holocene, suggesting that compared to the Younger Dryas more humid conditions occurred and that the lake received gradually increasing input of O-18-depleted groundwater or river water.