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Objective: Determining the perfusion status of central nervous system tissue during neurosurgical procedures can be of diagnostic and therapeutic value. We hypothesized that during decompressive craniectomy performed for malignant stroke, ischemic regions as well as healthy tissue can be differentiated[for full text, please go to the a.m. URL], 65. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)

Aims. Occultations of bright stars by planets provide information on the state of their atmospheres. An occultation of the bright star 45 Capricornii (HIP 107302) by Jupiter occurred on the night of 3/4 August 2009. Methods. The event was observed at multiple sites in Europe, Africa and South America and with instruments ranging in aperture from 0.4 m to 2.2 m. All observations, except one, were carried out in methane absorption bands centred at 0.89 μm and 2.2 μm to minimise the planetary contribution to the measured stellar flux. Following the application of special post-processing techniques, differential photometry was performed. Nearby bright satellites were used as reference sources. Results. Fifteen lightcurves were obtained. The photometric time series for fourteen of these were fitted to a model atmosphere of constant scale height (H). Estimates of H for most lightcurves lie within the range 20-30 km with an inverse-variance weighted mean of 23.6 ± 0.4 km, in good agreement with previous works. A comparison between half-light times at ingress and at egress implies an astrometric offset of 10-15 mas in Jupiter's position relative to the star. Five lightcurves - two for ingress and three for egress - were numerically inverted into profiles of pressure versus temperature. Isothermal, mutually consistent behaviour is observed within the pressure range 3-10 μbar. The inferred temperature of 165 ± 5 K is consistent with, but slightly higher than, that measured by the Galileo Probe at 5 S latitude in 1995 at the same pressure level. Subtraction of isothermal models for nine cases show the presence of at least one, and possibly two, non-isothermal layers a few tens of km below the half-light datum. Their altitudes are similar to those of features previously reported during the occultation of HIP 9369 in 1999. Our temperature estimates are consistent with the expected small magnitude of the perturbation of the atmosphere following the impact event on Jupiter in July 2009. © ESO, 2013.

There is clear geomorphological evidence for two phases of corrie glaciation at Keskadale in the English Lake District. Two10Be exposure ages provides preliminary insight into the timing of advance and retreat of the corrie glacier during the YoungerDryas (12.9-11.7 ka). It is hypothesised in this paper that the corrie glacier at the head of Keskadale reached its maximumextent early in the Younger Dryas, then retreated to occupy only the upper corrie basin in the later part of this cold interval.Glacier-climate modelling illustrates that this is consistent with palaeoecological evidence from northern England (and alsonumerous studies from Europe) of a climatically-variable Younger Dryas. The geomorphological evidence of multiple advancesor still stands is not restricted to Keskadale but is replicated at sites across the Lake District.

Glacial geomorphological mapping, 10Be terrestrial cosmogenic isotope analyses and palaeoglacier-climate modelling in the highest peaks of the Atlas Mountains, Morocco (31.1°N, 7.9°W), provides new and novel data toward understanding the history and evolution of the largest desert region on Earth. The Atlas Mountains display evidence of extensive and multiple Pleistocene glaciations. The largest ice field and valley glaciers formed in the Toubkal massif. Here, the oldest moraines have yielded 10Be ages scattered in the range 74-31 ka. A later phase of glaciation is dated to c. 24 ka. Moraines belonging to a third phase of glaciation has yielded a series of very close exposure ages (within error) at around 12 ka, and falling within the Younger Dryas (12.9-11.7 ka). The glacial record of the High Atlas effectively reflects moisture supply to the north-western Sahara Desert and can provide an indication of shifts between arid and pluvial conditions. The low altitude of the glaciations in all three glacial episodes indicate that climate was not only significantly cooler than today, but also very much wetter. The new evidence on the extent, timing and palaeoclimatic significance of glaciations in this region has major implications for understanding moisture transfer between the North Atlantic Ocean and the Sahara Desert during Pleistocene cold stages. The findings are highly significant for understanding atmospheric circulation during pluvial phases recorded in the Sahara, such as during the African Humid Period at the Pleistocene/Holocene transition (15 to 6 ka). Glacier advance in the High Atlas during this interval provides insight into the seasonal distribution of precipitation and provides valuable insight into the respective roles of moisture supply from the North Atlantic depressions and the West African Monsoon. This in turn then has important bearing on the strengths of meridional vs. zonal circulation at mid-latitudes during pluvial phases.

There is clear geomorphological evidence for two phases of corrie glaciation at Keskadale in the English Lake District. Two 10Be exposure ages provide preliminary insight into the timing of advance and retreat of the corrie glacier during the Younger Dryas (12.9-11.7 ka). It is hypothesised in this paper that the corrie glacier at the head of Keskadale reached its maximum extent early in the Younger Dryas, then retreated to occupy only the upper corrie basin in the later part of this cold interval. Glacier-climate modelling illustrates that this is consistent with palaeoecological evidence from northern England (and also numerous studies from Europe) of a climatically-variable Younger Dryas. The geomorphological evidence of multiple advances or still stands is not restricted to Keskadale but is replicated at sites across the Lake District.

In 2003, a National Electrostatics Corporation (NEC) 5MV tandem accelerator mass spectrometer was installed at SUERC, providing the radiocarbon laboratory with 14C measurements to 4–5‰ repeatability. In 2007, a 250kV single-stage accelerator mass spectrometer (SSAMS) was added to provide additional 14C capability and is now the preferred system for 14C analysis. Changes to the technology and to our operations are evident in our copious quality assurance data: typically, we now use the 134-position MC-SNICS source, which is filled to capacity. Measurement of standards shows that spectrometer running without the complication of on-line δ13C evaluation is a good operational compromise. Currently, 3‰ 14C/13C measurements are routinely achieved for samples up to nearly 3 half-lives old by consistent sample preparation and an automated data acquisition algorithm with sample random access for measurement repeats. Background and known-age standard data are presented for the period 2003–2008 for the 5MV system and 2007–2008 for the SSAMS, to demonstrate the improvements in data quality.

The offshore and coastal geomorphology of southwest Greenland records evidence for the advance and decay of the Greenland Ice Sheet during the Last Glacial Maximum. Regional ice flow patterns in the vicinity of Sisimiut show an enlarged ice sheet that extended southwestwards on to the shelf, with an ice stream centred over Holsteinsborg dyb. High level periglacial terrain composed of blockfield and tors is dated to between 101 – 142 ka using 26Al and 10Be cosmogenic exposure ages. These limit the maximum surface elevation of the Last Glacial Maximum ice sheet in this part of southwest Greenland to ca 750 – 810 m asl, and demonstrate that terrain above this level has been ice free since MIS 6. Last Glacial Maximum ice thickness on the coast of ca 700 m implies that the ice sheet reached the mid to outer continental shelf edge to form the Outer Hellefisk moraines. Exposure dates record ice surface thinning from 21.0 to 9.8 ka, with downwasting rates varying from 0.06 to 0.12m yr-1. This reflects strong surface ablation associated with increased air temperatures running up to the Bølling Interstadial (GIS1e) at ca 14 ka, and later marine calving under high sea levels. The relatively late retreat of the Itilleq ice stream inland of the present coastline is similar to the pattern observed at Jakobshavn Isbræ, located 250 km north in Disko Bugt, which also retreated from the continental shelf after ca 10 ka. We hypothesise that the ice streams of West Greenland persisted on the inner shelf until the early Holocene because of their considerable ice thickness and greater ice discharge compared with the adjacent ice sheet.

The Altai range (western Mongolia) accommodates NNE–SSW shortening across the northern India–Eurasia collision zone by dextral slip on faults trending NNW–SSE, and anticlockwise, vertical-axis rotations of fault-bounded blocks. However, fault slip-rates and the way in which faulting evolves over time are poorly understood, and form the motivation for this study. We focussed on the Har-Us-Nuur fault, a major transpressional fault bounding the eastern margin of the Altai. Three abandoned alluvial fan surfaces, each displaced right-laterally by the fault, were targeted for dating with cosmogenic 10Be and quartz optically stimulated luminescence (OSL). The first surface (A2) shows an exponential decrease in 10Be with increasing depth, with a significant inherited component. Modelling this profile yielded a minimum age of 74.1 ka. Material from the same sampling pit was dated at ~19 ka with OSL, but we consider this younger age to be incorrect, possibly due to feldspar contamination or abnormal quartz OSL characteristics. The A2 surface is displaced by 175 m, implying a (maximum) dextral slip-rate of 2.4±0.4 mm yr−1. A second fan surface (F1) was dated at ~6 ka with OSL and shows little variation in 10Be with depth, consistent with this young age. The inherited component is higher than for A2, indicating contrasting levels of inheritance for different periods of fan aggradation. A final surface (F2) shows scattered 10Be concentrations and lacks material suitable for OSL, so cannot be dated precisely. Using the total vertical displacement across the fault, we place the initiation of movement on the fault at ~2 Ma, significantly later than the late Oligocene to Miocene (28–5 Ma) onset of shortening in the Altai region. This suggests that deformation in the Altai has widened over time to incorporate new faults at the range margins (such as Har-Us-Nuur), possibly because older faults in the range interior have rotated about vertical axes into orientations that require work to be done against gravity.

The well-preserved glacial record in Argentine Patagonia offers a ~ 1 Ma archive of terrestrial climate extremes in southern South America. These glacial deposits remain largely undated beyond the range of radiocarbon dating at ca. 40 ka. Dating old glacial deposits (> several 105 a) by cosmogenic surface exposure methods is problematic because of the uncertainty in moraine degradation and boulder erosion rates. Here, we show that cobbles on outwash terraces can reliably date ‘old’ glacial deposits in the Lago Pueyrredón valley, 47.5° S, Argentina. Favorable environmental conditions (e.g., aridity and strong winds) have enabled continuous surface exposure of cobbles and preservation of outwash terraces. The data demonstrate that nuclide inheritance is negligible and we therefore use the oldest surface cobbles to date the deposit. 10Be concentrations in outwash cobbles reveal a major glacial advance at ca. 260 ka, concurrent with Marine Isotope Stage 8 (MIS 8) and dust peaks in Antarctic ice cores. A 10Be concentration depth-profile in the outwash terrace supports the age and suggests a low terrace erosion rate of ca. 0.5 mm ka− 1. We compare these data to exposure ages obtained from associated moraines and find that surface boulders underestimate the age of the glaciation by ~ 100 ka; thus the oldest boulders in this area do not date closely moraine deposition. The 10Be concentration in moraine cobbles help to constrain moraine degradation rates. These data together with constraints from measured 26Al/10Be ratios suggest that all moraine boulders were likely exhumed after original deposition. We determine the local Last Glacial Maximum (LGM) occurred at ~ 27–25 ka, consistent with the maximum LGM in other parts of Patagonia.

The 230Thxs-normalization method is a widely used tool for the calculation of vertical fluxes to marine sediments, correcting for the influence of lateral sediment transport. However, the strong particle surface reactivity of thorium may lead to a grain size specific distribution of 230Th. Lateral transport during particle settling might have a sorting effect on particles, thus affecting the sedimentary 230Th signal as well. In this study, the specific distribution pattern of 230Th within different particle classes is investigated in carbonate-rich sediments and opal-rich sediments from the Atlantic Ocean. Sediments were split into distinct particle classes by wet-sieving and settling. The results show a clear preference of 230Th for the smallest particle sizes. Both in carbonate-rich and opal-rich sediment, most of the 230Th is bound within the particle size class

Forty-eight soil profiles down to a depth of 40 cm were taken in Russia and Ukraine in 1995 and 1997, respectively, in order to investigate the feasibility of retrospective dosimetry of the 131I exposure after the Chernobyl accident via the long-lived 129I. The sampling sites covered areas almost not affected by fallout from the Chernobyl accident such as Moscow/Russia and the Zhitomir district in Ukraine as well as the highly contaminated Korosten and Narodici districts in Ukraine. 129I was analyzed by radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS). 127I was measured for some profiles by RNAA or ion chromatography. The results for 127I demonstrated large differences in the capabilities of the soils to store iodine over long time-spans. The depth profiles of 129I and of 137Cs showed large differences in the migration behavior between the two nuclides but also for each nuclide among the different sampling sites. Though it cannot be quantified how much 129I and 137Cs was lost out of the soil columns into deeper depths, the inventories in the columns were taken as proxies for the total inventories. For 129I, these inventories were at least three orders of magnitude higher than a pre-nuclear value of 0.084 ± 0.017 mBq m-2 derived from a soil profile taken in 1939 in Lutovinovo/Russia. From the samples from Moscow and Zhitomir a pre-Chernobyl 129I inventory of (44 ± 24) mBq m-2 was determined, limiting the feasibility of 129I retrospective dosimetry to areas where the 129I inventories exceed 100 mBq m-2. Higher average 129I inventories in the Korosten and Narodici districts of 130 mBq m-2 and 848 mBq m-2, respectively, allowed determination of the 129I fallout due to the Chernobyl accident. Based on the total 129I inventories and on literature data for the atomic ratio of 129I/131I = 13.6 ± 2.8 for the Chernobyl emissions and on aggregated dose coefficients for 131I, the thyroid exposure due to 131I after the Chernobyl accident was estimated for the inhabitants of 4 villages in the Korosten and of 3 villages in the Narodici districts. The limitations and uncertainties of the 129I retrospective dosimetry are discussed., Сорок вісім ґрунтових профілів вниз на глибину 40 см, були взяті в Росії і Україні в 1995 і 1997 роках, відповідно, з метою вивчення можливості ретроспективної дозиметрії експозиції 131I після Аварії на Чорнобильській АЕС через тривалий період розпаду 129I. Місця відбору проб охоплює області майже не постраждалі від радіоактивних опадів від аварії на Чорнобильській АЕС, таких як Москва / Росія і Житомирської області в Україні, а також сильно забруднені території Коростенського і Народицького районів в Україні. 129I аналізували за допомогою радіохімічного нейтрона активаційного аналізу (RNAA) і прискорювача мас-спектрометрії (AMS). 127I вимірювали для деяких профілів за допомогою RNAA або іонної хроматографії. Результати для 127I показали значні відмінності в можливостях ґрунту для зберігання йоду протягом тривалих часових відрізків. На глибині профілю 129I і 137Cs показали значні відмінності в поведінці міграції між двома нуклідами і для кожного нукліда серед різних проб. Хоча це не може бути визначено кількісно, ​​скільки 129I і 137Cs було втрачено з ґрунту колон в більш глибоких профілях, кадастри в колонках були взяті в якості довірених осіб на загальну суму товарно-матеріальних запасів. Для 129I, ці запаси були принаймні на три порядки вище, ніж в доядерній вартості отриманих 0,084 ± 0,017 МБк м-2 з ґрунтового профілю, прийнятим в 1939 році в Лутовиново / Росії. З зразків з Москви і Житомир попередньо Чорнобильська 129I інвентаризації (44 ± 24) мБк м-2 було визначено, що обмежує можливості 129I в ретроспективі дозиметрії в районах, де запаси 129I перевищують 100 МБк м-2. Більш високі середні запаси 129I в Коростенському і Народицькому районах 130 МБк м-2 і 848 мБк м-2, відповідно, допускається визначення 129I радіоактивні опади в результаті аварії на Чорнобильській АЕС. На основі загальних запасів 129I і літературних даних для атомного відношення 129I / 131I = 13,6 ± 2,8 для викидів Чорнобильської АЕС і на агрегованих коефіцієнтів дози для 131I, опромінення щитовидної залози 131I після аварії на Чорнобильській АЕС була оцінена для жителів 4 сіл Коростенського і 3 сіл в Народицького районів. Обмеження і невизначеності в ретроспективі 129I дозиметрії обговорюються., Сорок восемь грунтовых профилей вниз на глубину 40 см, были взяты в России и Украине в 1995 и 1997 годах, соответственно, с целью изучения возможности ретроспективной дозиметрии экспозиции 131I после Аварии на Чернобыльской АЭС через длительный период распада 129I. Места отбора проб охватывает области почти не пострадавшие от радиоактивных осадков от аварии на Чернобыльской АЭС, таких как Москва / Россия и Житомирской области в Украине, а также сильно загрязненные территории Коростенского и Народичского районов в Украине. 129I анализировали с помощью радиохимического нейтрона активационного анализа (RNAA) и ускорителя масс-спектрометрии (AMS). 127I измеряли для некоторых профилей с помощью RNAA или ионной хроматографии. Результаты для 127I показали значительные различия в возможностях почвы для хранения йода в течение длительных временных отрезков. На глубине профиля 129I и 137Cs показали значительные различия в поведении миграции между двумя нуклидами и для каждого нуклида среди различных проб. Хотя это не может быть определено количественно, сколько 129I и 137Cs было потеряно из почвы колонн в более глубоких профилей, кадастры в колонках были взяты в качестве доверенных лиц на общую сумму товарно-материальных запасов. Для 129I, эти запасы были по крайней мере на три порядка выше, чем в доядерных стоимости полученных 0,084 ± 0,017 МБк м 2 с почвенного профиля, принятым в 1939 году в Лутовиново / России. С образцов из Москвы и Житомир предварительно Чернобыльская 129I инвентаризации (44 ± 24) мБк м 2 было определено, что ограничивает возможности 129I в ретроспективе дозиметрии в районах, где запасы 129I превышают 100 МБк м 2. Более высокие средние запасы 129I в Коростенском и Народичском районах 130 МБк м 2 и 848 мБк м 2, соответственно, допускается определение 129I радиоактивные осадки в результате аварии на Чернобыльской АЭС. На основе общих запасов 129I и литературных данных для атомного отношения 129I / 131I = 13,6 ± 2,8 для выбросов Чернобыльской АЭС и на агрегированных коэффициентов дозы для 131I, облучение щитовидной железы 131I после аварии на Чернобыльской АЭС была оценена для жителей 4 сел Коростенского и 3 сел в Народичского районов. Ограничения и неопределенности в ретроспективе 129I дозиметрии обсуждаются.

In the framework EU Project STACCATO (Influence of Stratosphere-Troposphere Exchange in A Changing Climate on Atmospheric Transport and Oxidation Capacity), the first long-term, simultaneous monitoring of the two cosmogenic radionuclides 7Be and 10Be was performed. Emphasis was paid to a high-resolution record of the data, too. A comprehensive data set was created in order to validate model calculations and to provide an independent estimate of the strength of atmospheric transport processes, such as stratosphere-troposphere exchange. For that reason, particle-bound beryllium isotopes were collected at three high-alpine meteorological stations: at Sonnblick (Austria), Zugspitze (Germany) and Jungfraujoch (Switzerland), respectively. A total of 400 daily or bi-daily 10Be measurements are now available. While 7Be sampling and measurement processes are well standardized, the determination of 10Be concentrations using AMS is more complicated. For that reason an extensive description of the 10Be measurement is given. Moreover, the basic characteristics of the 10Be/7Be ratios are presented, leading to a mean annual value of 2.08 and 1.82 for Jungfraujoch and Zugspitze, respectively. Analysis in combination with meteorological parameters shows the usefulness of the ratio as an index of stratosphere-to-troposphere transport (STT), especially when wet scavenging becomes important. Regression analysis of the 10Be/ 7Be ratio with 7Be, 10Be and relative humidity revealed that the ratio is virtually independent from the effect of wet scavenging while inspection of the weather patterns related to the highest ratios indicated the presence of typical patterns for stratospheric intrusions. Nevertheless, although the 10Be/7Be ratio can be successful in identifying certain STT cases it is a difficult parameter for an automated stratospheric intrusion detection algorithm. © 2004 Elsevier B.V. All rights reserved.