Mass-movement and flood-induced deposits in Lake Ledro, southern Alps, Italy: implications for Holocene palaeohydrology and natural hazards

High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and riverbed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events) in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments have been finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events (SEs): light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography) of the organic matter present in soil, riverbed and lacustrine samples together with lake sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass-movements triggered by historical and pre-historical regional earthquakes dated to AD2005, AD1891, AD1045 and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11 495 cal. yr BP. Darkcoloured SEs develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and lignocellulosic debris) and are interpreted as resulting from intense hyperpycnal flood event. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 5mm during the largest Holocene flood events. Such significant soil erosion is interpreted as resulting from the combination of heavy rainfall and snowmelt. The recurrence of flash flood events during the Holocene was, however, not high enough to affect pedogenesis processes and highlight several wet regional periods during the Holocene. The Holocene period is divided into four phases of environmental evolution. Over the first half of the Holocene, a progressive stabilization of the soils present through the catchment of Lake Ledro was associated with a progressive reforestation of the area and only interrupted during the wet 8.2 event when the soil destabilization was particularly important. Lower soil erosion was recorded during the mid-Holocene climatic optimum (8000-4200 cal. yr BP) and associated with higher algal production. Between 4200 and 3100 cal. yr BP, both wetter climate and human activities within the drainage basin drastically increased soil erosion rates. Finally, from 3100 cal. yr BP to the present-day, data suggest increasing and changing human land use.

The IS/OS junction layer in the natural history of type 2 idiopathic macular telangiectasia

To document the progression of a break in the photoreceptor inner segment/outer segment (IS/OS) junction layer and its functional correlates over time in the natural history of type 2 idiopathic macular telangiectasia (type 2 MacTel).

Graves' ophthalmopathy: natural history and treatment outcomes

The pathogenesis of Graves' ophthalmopathy has not been yet clarified, and from a therapeutic standpoint Graves' ophthalmopathy remains an enigma. The natural course and effects of different treatment regimens are poorly documented.

Four thousand years of vegetation and fire history in the spruce forests of northern Kyrgyzstan (Kungey Alatau, Central Asia)

Analyses of pollen, macrofossils and microscopic charcoal in the sediment of a small sub-alpine lake (Karakol, Kyrgyzstan) provide new data to reconstruct the vegetation history of the Kungey Alatau spruce forest during the late-Holocene, i.e. the past 4,000 years. The pollen data suggest that Picea schrenkiana F. and M. was the dominant tree in this region from the beginning of the record. The pollen record of pronounced die-backs of the forests, along with lithostratigraphical evidence, points to possible climatic cooling (and/or drying) around 3,800 cal year B.P., and between 3,350 and 2,520 cal year B.P., with a culmination at 2,800-2,600 cal B.P., although stable climatic conditions are reported for this region for the past 3,000-4,000 years in previous studies. From 2,500 to 190 cal year B.P. high pollen values of P. schrenkiana suggest rather closed and dense forests under the environmental conditions of that time. A marked decline in spruce forests occurred with the onset of modern human activities in the region from 190 cal year B.P. These results show that the present forests are anthropogenically reduced and represent only about half of their potential natural extent. As P. schrenkiana is a species endemic to the western Tien Shan, it is most likely that its refugium was confined to this region. However, our palaeoecological record is too recent to address this hypothesis thoroughly.

Natural history of optical coherence tomography-detected non-flow-limiting edge dissections following drug-eluting stent implantation

Aims: Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections -particularly non-flow-limiting- compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Methods and results: Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. Conclusions: OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

Spring temperature variability and eutrophication history inferred from sedimentary pigments in the varved sediments of Lake Żabińskie, north-eastern Poland, AD 1907–2008

Varved lake sediments are excellent natural archives providing quantitative insights into climatic and environmental changes at very high resolution and chronological accuracy. However, due to the multitude of responses within lake ecosystems it is often difficult to understand how climate variability interacts with other environmental pressures such as eutrophication, and to attribute observed changes to specific causes. This is particularly challenging during the past 100 years when multiple strong trends are superposed. Here we present a high-resolution multi-proxy record of sedimentary pigments and other biogeochemical data from the varved sediments of Lake Żabińskie (Masurian Lake District, north-eastern Poland, 54°N–22°E, 120 m a.s.l.) spanning AD 1907 to 2008. Lake Żabińskie exhibits biogeochemical varves with highly organic late summer and winter layers separated by white layers of endogenous calcite precipitated in early summer. The aim of our study is to investigate whether climate-driven changes and anthropogenic changes can be separated in a multi-proxy sediment data set, and to explore which sediment proxies are potentially suitable for long quantitative climate reconstructions. We also test if convoluted analytical techniques (e.g. HPLC) can be substituted by rapid scanning techniques (visible reflectance spectroscopy VIS-RS; 380–730 nm). We used principal component analysis and cluster analysis to show that the recent eutrophication of Lake Żabińskie can be discriminated from climate-driven changes for the period AD 1907–2008. The eutrophication signal (PC1 = 46.4%; TOC, TN, TS, Phe-b, high TC/CD ratios total carotenoids/chlorophyll-a derivatives) is mainly expressed as increasing aquatic primary production, increasing hypolimnetic anoxia and a change in the algal community from green algae to blue-green algae. The proxies diagnostic for eutrophication show a smooth positive trend between 1907 and ca 1980 followed by a very rapid increase from ca. 1980 ± 2 onwards. We demonstrate that PC2 (24.4%, Chl-a-related pigments) is not affected by the eutrophication signal, but instead is sensitive to spring (MAM) temperature (r = 0.63, pcorr < 0.05, RMSEP = 0.56 °C; 5-yr filtered). Limnological monitoring data (2011–2013) support this finding. We also demonstrate that scanning visible reflectance spectroscopy (VIS-RS) data can be calibrated to HPLC-measured chloropigment data and be used to infer concentrations of sedimentary Chl-a derivatives {pheophytin a + pyropheophytin a}. This offers the possibility for very high-resolution (multi)millennial-long paleoenvironmental reconstructions.

Natural history of surgically treated high-risk prostate cancer

BACKGROUND No data exist on the patterns of biochemical recurrence (BCR) and their effect on survival in patients with high-risk prostate cancer (PCa) treated with surgery. The aim of our investigation was to evaluate the natural history of PCa in patients treated with radical prostatectomy (RP) alone. MATERIALS AND METHODS Overall, 2,065 patients with high-risk PCa treated with RP at 7 tertiary referral centers between 1991 and 2011 were identified. First, we calculated the probability of experiencing BCR after surgery. Particularly, we relied on conditional survival estimates for BCR after RP. Competing-risks regression analyses were then used to evaluate the effect of time to BCR on the risk of cancer-specific mortality (CSM). RESULTS Median follow-up was 70 months. Overall, the 5-year BCR-free survival rate was 55.2%. Given the BCR-free survivorship at 1, 2, 3, 4, and 5 years, the BCR-free survival rates improved by+7.6%,+4.1%,+4.8%,+3.2%, and+3.7%, respectively. Overall, the 10-year CSM rate was 14.8%. When patients were stratified according to time to BCR, patients experiencing BCR within 36 months from surgery had higher 10-year CSM rates compared with those experiencing late BCR (19.1% vs. 4.4%; P<0.001). At multivariate analyses, time to BCR represented an independent predictor of CSM (P<0.001). CONCLUSIONS Increasing time from surgery is associated with a reduction of the risk of subsequent BCR. Additionally, time to BCR represents a predictor of CSM in these patients. These results might help provide clinicians with better follow-up strategies and more aggressive treatments for early BCR.

The Use of New Technology and Occupational Mobility: An Event History Analysis of the Swiss Labor Market

The investigation of the consequences of new technologies has a long standing tradition within economics. Particularly, labor economists are wondering how the introduction of new technologies, e.g. Personal Computers, have shaped labor markets. Former research has concentrated on the question of whether on-the-job use of PCs creates a wage bonus for employees. In this paper, we investigate whether the use of PCs increases employees’ probability of an upward shift in their employment status and whether it reduces the risk of involuntary labor market exits. We do so by applying event history analysis to the Swiss Labor Market Survey, a random sample of 3028 respondents, and by analyzing a Panel sub-sample of 650 respondents conducted recently in Switzerland. Our results show that on-the-job use of PCs was beneficial for employees in the past by increasing their probability of an upward shift by approximately 50%. The analysis also suggests that PC use reduces the risk and duration of unemployment. However, these latter results fail to reach statistical significance.

Reconstructing 4000 years of mass movement and tsunami history in a deep peri-Alpine lake (Lake Geneva, France-Switzerland)

The study of mass movements in lake sediments provides insights into past natural hazards at historic and prehistoric timescales. Sediments from the deep basin of Lake Geneva reveal a succession of six large-scale (volumes of 22 × 106 to 250 × 106 m3) mass-transport deposits, associated with five mass-movement events within 2600 years (4000 cal bp to 563 ad). The mass-transport deposits result from: (i) lateral slope failures (mass-transport deposit B at 3895 ± 225 cal bp and mass-transport deposits A and C at 3683 ± 128 cal bp); and (ii) Rhône delta collapses (mass-transport deposits D to G dated at 2650 ± 150 cal bp, 2185 ± 85 cal bp, 1920 ± 120 cal bp and 563 ad, respectively). Mass-transport deposits A and C were most probably triggered by an earthquake, whereas the Rhône delta collapses were likely to be due to sediment overload with a rockfall as the external trigger (mass-transport deposit G, the Tauredunum event in 563 ad known from historical records), an earthquake (mass-transport deposit E) or unknown external triggers (mass-transport deposits D and F). Independent of their origin and trigger mechanisms, numerical simulations show that all of these recorded mass-transport deposits are large enough to have generated at least metre-scale tsunamis during mass movement initiation. Since the Tauredunum event in 563 ad, two small-scale (volumes of 1 to 2 × 106 m3) mass-transport deposits (H and I) are present in the seismic record, both of which are associated with small lateral slope failures. Mass-transport deposits H and I might be related to earthquakes in Lausanne/Geneva (possibly) 1322 ad and Aigle 1584 ad, respectively. The sedimentary record of the deep basin of Lake Geneva, in combination with the historical record, show that during the past 3695 years, at least six tsunamis were generated by mass movements, indicating that the tsunami hazard in the Lake Geneva region should not be neglected, although such events are not frequent with a recurrence time of 0·0016 yr−1.