Late Glacial and Holocene vegetational changes on the Ulagan high-mountain plateau, Altai Mountains, southern Siberia

Three well-dated pollen diagrams from 1985 m, 2050 m, and at the tree line at 2150 m asl show the vegetational succession in the central Altai Mountains since 16 cal ka BP. Pioneer vegetation after deglaciation was recorded first at the lowest site. Subsequently, dense dry steppe vegetation developed coincident with the change from silt to organic sediments at the two lower sites, but silt lasted longer at the highest site, indicating the persistence of bare ground there. Forests of Pinus sibirica, Pinus sylvestris, Picea obovata, Larix sibirica, Abies sibirica, and Betula pendula started to develop about 12 cal ka BP with the change to a warmer and wetter climate at the beginning of the Holocene. Results indicate that the timberline did not rise above the highest site. Mesophilous dark-coniferous forests were fully developed by 9.5 cal ka BP. The role of Abies and Picea decreased by about 7.5 cal ka BP suggesting cooler climate, after which the forests changed little until today. The vegetational development in this portion of the central Altai Mountains is compatible with that described in neighbouring areas of the Altai, southern Siberia, Mongolia, and Kazakhstan.

Liulin silicon semiconductor spectrometers as cosmic ray monitors at the high mountain observatories Jungfraujoch and Lomnický stit

Currently, most cosmic ray data are obtained by detectors on satellites, aircraft, high-altitude balloons and ground (neutron monitors). In our work, we examined whether Liulin semiconductor spectrometers (simple silicon planar diode detectors with spectrometric properties) located at high mountain observatories could contribute new information to the monitoring of cosmic rays by analyzing data from selected solar events between 2005 and 2013. The decision thresholds and detection limits of these detectors placed at Jungfraujoch (Switzerland; 3475 m a.s.l.; vertical cut-off rigidity 4.5 GV) and Lomnicky stıt (Slovakia; 2633 m a.s.l.; vertical cut-off rigidity 3.84 GV) highmountain observatories were determined. The data showed that only the strongest variations of the cosmic ray flux in this period were detectable. The main limitation in the performance of these detectors is their small sensitive volume and low sensitivity of the PIN photodiode to neutrons.

Post mortem computed tomography and core needle biopsy in comparison to autopsy in eleven bernese mountain Dogs with histiocytic sarcoma

Background: Bernese mountain dogs are reported to have a shorter life expectancy than other breeds. A Major reason for this has been assigned to a high tumour prevalence, especially of histiocytic sarcoma. The efforts made by the breeding clubs to improve the longevity with the help of genetic tests and breeding value estimations are impeded by insufficiently reliable diagnoses regarding the cause of death. The current standard for post mortem examination in animals is performance of an autopsy. In human forensic medicine, imaging modalities, such as computed tomography and magnetic resonance imaging, are used with increasing frequency as a complement to autopsy. The present study investigates, whether post mortem computed tomography in combination with core needle biopsy is able to provide a definitive diagnosis of histiocytic sarcoma. For this purpose we have analysed the results of post mortem computed tomography and core needle biopsy in eleven Bernese mountain dogs. In the subsequent autopsy, every dog had a definitive diagnosis of histiocytic sarcoma, based on immunohistochemistry. Results: Computed tomography revealed space-occupying lesions in all dogs. Lesion detection by post mortem computed tomography was similar to lesion detection in autopsy for lung tissue (9 cases in computed tomography / 8 cases in autopsy), thoracic lymph nodes (9/8), spleen (6/7), kidney (2/2) and bone (3/3). Hepatic nodules, however, were difficult to detect with our scanning protocol (2/7). Histology of the core needle biopsies provided definitive diagnoses of histiocytic sarcoma in ten dogs, including confirmation by immunohistochemistry in six dogs. The biopsy samples of the remaining dog did not contain any identifiable neoplastic cells. Autolysis was the main reason for uncertain histological diagnoses. Conclusions: Post mortem computed tomography is a fast and effective method for the detection of lesions suspicious for histiocytic sarcoma in pulmonary, thoracic lymphatic, splenic, osseous and renal tissue. Optimization of the procedure regarding the scanning protocol and tissue sample size and number will improve the accuracy of the method. Keywords: Post mortem computed tomography, Core needle biopsy, Bernese mountain dog, Histiocytic sarcoma, Autopsy

Paleoglaciated landscapes in Simen and other high-mountain areas of Ethiopia

In the present-day Ethiopia, glaciated landscapes do not exist, but paleoglaciated landscapes have been documented on a few mountain tops, which have altitudes higher than about 4,350 m asl in northern Ethiopia (Simen Mountains) and about 4,100 m asl in southern Ethiopia (Arsi and Bale Mountains). Glaciers were associated with the Late Pleistocene cold stages and reached as far down as 3,760 m asl in northern and 3,200 m asl in southern Ethiopia. Bale Mountains had the most extensive Late Pleistocene glaciation, covering over 190 km2, followed by Arsi Mountains (about 85 km2). In Simen, the Late Pleistocene glaciers covered merely 13 km2. In addition, paleo-periglacial slope deposits are found on all above-mentioned paleoglaciated mountains and in further mountain systems which did not host glaciers. This allows the reconstruction of the Late Pleistocene paleoclimate as being about 8 °C colder than at present (2014), much more dry, and probably without monsoon, at least in northern Ethiopia. Most probably in the Early Holocene, the re-emergence of monsoonal rains led to a strong erosion phase, which was followed by an extended stable phase with soil formation, building up about 70-cm-deep A-horizons (Andosol) on the paleo-periglacial slope deposits. These soils have been heavily degraded due to human-induced soil erosion up to about 3800 m asl since agriculture started several decades to millennia ago.

Eclogitic diamonds from variable crustal protoliths in the northeastern Siberian craton: trace elements and coupled δ13C – δ18O signatures in diamonds and garnet inclusions

Diamonds of eclogitic assemblages are dominant in the placer diamond deposits of the northeastern Siberian platform. In this study we present new trace elements and stable isotopes (δ13C and δ18O) data for alluvial diamonds and their garnet inclusions from this locality. Cr-rich garnets of peridotitic affinity in the studied diamonds have a narrow range of δ18O values from 5.7‰ to 6.2‰, which is largely overlapping with the accepted mantle range. This narrow range suggests that the garnet inclusions showing different REE patterns and little variations in oxygen isotopes may have formed by different processes involving fluid/melts that, however, were in oxygen isotopic equilibrium with the mantle. The trace element composition of the eclogitic garnet inclusions supports a crustal origin for at least the high-Ca garnets, which show flat HREE patterns and in some cases a positive Eu-anomaly. High-Ca eclogitic garnets generally show heavier oxygen isotope compositions (δ18O 6.5–9.6‰) than what is observed in low-Ca garnets (δ18O 5.7–7.4‰). The variability in oxygen isotopes and trace elements is suggested to be inherited from contrasting crustal protoliths. The relationship between the high δ18O values of inclusions and the low δ13C values of the host diamonds implies that the high-Ca garnet inclusions were derived from intensely hydrated (e.g., δ18O > 7‰) and typically oxidised basaltic rock close to the seawater interface, and that the carbon for diamonds was closely associated with this protolith.

Sleep disordered breathing and vascular function in patients with chronic mountain sickness and healthy high-altitude dwellers.

Background Chronic mountain sickness (CMS) is often associated with vascular dysfunction, but the underlying mechanism is unknown. Sleep disordered breathing (SDB) frequently occurs at high altitude. At low altitude SDB causes vascular dysfunction. Moreover, in SDB, transient elevations of right-sided cardiac pressure may cause right-to-left shunting in the presence of a patent foramen ovale (PFO) and, in turn, further aggravate hypoxemia and pulmonary hypertension. We speculated that compared to healthy high-altitude dwellers, in patients with CMS, SDB and nocturnal hypoxemia are more pronounced and related to vascular dysfunction. Methods We performed overnight sleep recordings, and measured systemic and pulmonary-artery pressure in 23 patients with CMS (mean±SD age 52.8±9.8 y) and 12 healthy controls (47.8±7.8 y) at 3600 m. In a subgroup of 15 subjects with SDB, we searched for PFO with transesophagal echocardiography. Results The major new findings were that in CMS patients, a) SDB and nocturnal hypoxemia was more severe (P<0.01) than in controls (apnea/hypopnea index, AHI, 38.9±25.5 vs. 14.3±7.8[nb/h]; SaO2, 80.2±3.6 vs. 86.8±1.7[%], CMS vs. controls), and b) AHI was directly correlated with systemic blood pressure (r=0.5216, P=0.001) and pulmonary-artery pressure (r=0.4497, P=0.024). PFO was associated with more severe SDB (AHI 48.8±24.7 vs. 14.8±7.3[nb/h], P=0.013, PFO vs. no PFO) and hypoxemia. Conclusion SDB and nocturnal hypoxemia are more severe in CMS patients than in controls and are associated with systemic and pulmonary vascular dysfunction. The presence of a PFO appeared to further aggravate SDB. Closure of PFO may improve SDB, hypoxemia and vascular dysfunction in CMS patients. Clinical Trials Gov Registration NCT01182792.

Reconstruction of Holocene vegetation dynamics at Lac de Bretaye, a high-mountain lake in the Swiss Alps

A deeper understanding of past vegetation dynamics is required to better assess future vegetation responses to global warming in the Alps. Lake sediments from Lac de Bretaye, a small subalpine lake in the Northern Swiss Alps (1780 m a.s.l.), were analysed to reconstruct past vegetation dynamics for the entire Holocene, using pollen, macrofossil and charcoal analyses as main proxies. The results show that timberline reached the lake’s catchment area at around 10,300 cal. BP, supporting the hypothesis of a delayed postglacial afforestation in the Northern Alps. At the same time, thermophilous trees such as Ulmus, Tilia and Acer established in the lowlands and expanded to the altitude of the lake, forming distinctive boreo-nemoral forests with Betula, Pinus cembra and Larix decidua. From about 5000 to 3500 cal. BP, thermophilous trees declined because of increasing human land use, mainly driven by the mass expansion of Picea abies and severe anthropogenic fire activity. From the Bronze Age onwards (c. 4200–2800 cal. BP), grazing indicators and high values for charcoal concentration and influx attest an intensifying human impact, fostering the expansion of Alnus viridis and Picea abies. Hence, biodiversity in alpine meadows increased, whereas forest diversity declined, as can be seen in other regional records. We argue that the anticipated climate change and decreasing human impact in the Alps today will not only lead to an upward movement of timberline with consequent loss of area for grasslands, but also to a disruption of Picea abies forests, which may allow the re-expansion of thermophilous tree species.

Kohlpalmen Mountain Cabbage der Engl., ein junger Cocos-Baum und Bambus-Wald

Louise von Panhuys

Life, wanderings and labours in Eastern Africa : with an account of the first successful ascent of the equatorial snow mountain, Kilima Njaro, and remarks upon East African slavery

by Charles New, of the late Livingstone search and relief expedition