212 research outputs found
Mittelfristige Ergebnisse nach arthroskopischer Resektion des Schultereckgelenkes
27 Patienten, die sich einer arthroskopischen Resektion des Acromioclavicular-gelenkes unterzogen hatten, wurden nachuntersucht. Indikationen zur Operation waren die Osteolyse der lateralen Clavicula, die primäre Arthrose des AC-Gelenkes und die posttraumatische Schultereckgelenkarthrose. Die postoperativen Ergebnisse wurden mit dem Constant-Score und dem ASES-Score erhoben. Zur Untersuchung der Lebensqualität wurde der SF-36 Health Survey angewandt. Patienten mit einer Osteolyse zeigten in allen Scores die besten Resultate. Ein Zusammenhang zwischen dem Resektionsausmaß und dem Operationserfolg konnte nicht festgestellt werden. Nach den Ergebnissen dieser Arbeit und denen anderer Studien ist die arthroskopische AC-Gelenkresektion als ein geeignetes Verfahren bei isolierter AC-Gelenkarthrose anzusehen. Wichtig ist die strenge Indikationsstellung. Bei begleitender Instabilität des Gelenkes ist die offene Operation mit zusätzlichen stabilisierenden Maßnahmen notwendig
Internal conversion coefficients for superheavy elements
The internal conversion coefficients (ICC) were calculated for all atomic
subshells of the elements with 104<=Z<=126, the E1...E4, M1...M4
multipolarities and the transition energies between 10 and 1000 keV. The atomic
screening was treated in the relativistic Hartree-Fock-Slater model. The Tables
comprising almost 90000 subshell and total ICC were recently deposited at LANL
preprint server.Comment: 6 pages including 3 figures, needs files myown.sty and epsfig.sty
(both included
The Future of the Arctic: What Does It Mean for Sea Ice and Small Creatures?
The warming of our planet is changing the Arctic dramatically. The area covered by sea-ice is shrinking and the ice that is left is younger and thinner. We took part in an expedition to the Arctic, to study how these changes affect organisms living in and under the ice. Following this expedition, we found that storms can more easily break the thinner ice. Storms form cracks in the sea ice, allowing sunlight to pass into the water below, which makes algal growth possible. Algae are microscopic “plants” that grow in water or sea ice. Storms also brought thick heavy snow, which pushed the ice surface below the water. This flooded the snow and created slush. We discovered that this slush is another good habitat for algae. If Arctic sea ice continues to thin, and storms become more common, we expect that these algal habitats will become more important in the future
On the reliability of the theoretical internal conversion coefficients
Possible sources of uncertainties in the calculations of the internal
conversion coefficients are studied. The uncertainties induced by them are
estimated.Comment: 16 pages (including 3 figures inserted by 'epsfig' macro
Contribution of deformation to sea-ice mass balance: a case study from an N-ICE2015 storm
The fastest and most efficient process of gaining sea ice volume is through the mechanical redistribution of mass as a consequence of deformation events. During the ice growth season divergent motion produces leads where new ice grows thermodynamically, while convergent motion fractures the ice and either piles the resultant ice blocks into ridges or rafts one floe under the other. Here we present an exceptionally detailed airborne dataset from a 9km2 area of first and second year ice in the Transpolar Drift north of Svalbard that allowed us to estimate the redistribution of mass from an observed deformation event. To achieve this level of detail we analyzed changes in sea ice freeboard acquired from two airborne laser scanner surveys just before and right after a deformation event brought on by a passing low pressure system. A linear regression model based on divergence during this storm can explain 64% of freeboard variability. Over the survey region we estimated that about 1.3% of level sea ice volume was pressed together into deformed ice and the new ice formed in leads in a week after the deformation event would increase the sea ice volume by 0.5%. As the region is impacted by about 15 storms each winter a simple linear extrapolation would result in about 7% volume increase and 20% deformed ice fraction at the end of the seaso
Contribution of Deformation to Sea Ice Mass Balance: A Case Study From an N‐ICE2015 Storm
The seeding of ice algal blooms in Arctic pack ice: The multiyear ice seed repository hypothesis
Source at http://dx.doi.org/10.1002/2016JG003668 During the Norwegian young sea ICE expedition (N-ICE2015) from January to June 2015 the pack
ice in the Arctic Ocean north of Svalbard was studied during four drifts between 83° and 80°N. This pack ice
consisted of a mix of second year,
fi
rst year, and young ice. The physical properties and ice algal community
composition was investigated in the three different ice types during the winter-spring-summer transition.
Our results indicate that algae remaining in sea ice that survived the summer melt season are subsequently
trapped in the upper layers of the ice column during winter and may function as an algal seed repository.
Once the connectivity in the entire ice column is established, as a result of temperature-driven increase in ice
porosity during spring, algae in the upper parts of the ice are able to migrate toward the bottom and initiate
the ice algal spring bloom. Furthermore, this algal repository might seed the bloom in younger ice formed
in adjacent leads. This mechanism was studied in detail for the dominant ice diatom
Nitzschia frigida
. The
proposed seeding mechanism may be compromised due to the disappearance of older ice in the anticipated
regime shift toward a seasonally ice-free Arctic Ocean
Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ice
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 7 (2017): 40850, doi:10.1038/srep40850.The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms beneath ponded sea ice during summer, indicating that satellite-based Arctic annual primary production estimates may be significantly underestimated. Here we present a unique time-series of a phytoplankton spring bloom observed beneath snow-covered Arctic pack ice. The bloom, dominated by the haptophyte algae Phaeocystis pouchetii, caused near depletion of the surface nitrate inventory and a decline in dissolved inorganic carbon by 16 ± 6 g C m−2. Ocean circulation characteristics in the area indicated that the bloom developed in situ despite the snow-covered sea ice. Leads in the dynamic ice cover provided added sunlight necessary to initiate and sustain the bloom. Phytoplankton blooms beneath snow-covered ice might become more common and widespread in the future Arctic Ocean with frequent lead formation due to thinner and more dynamic sea ice despite projected increases in high-Arctic snowfall. This could alter productivity, marine food webs and carbon sequestration in the Arctic Ocean.This study was supported by the Centre for Ice, Climate and Ecosystems (ICE) at the Norwegian Polar Institute, the Ministry of Climate and Environment, Norway, the Research Council of Norway (projects Boom or Bust no. 244646, STASIS no. 221961, CORESAT no. 222681, CIRFA no. 237906 and AMOS CeO no. 223254), and the Ministry of Foreign Affairs, Norway (project ID Arctic), the ICE-ARC program of the European Union 7th Framework Program (grant number 603887), the Polish-Norwegian Research Program operated by the National Centre for Research and Development under the Norwegian Financial Mechanism 2009–2014 in the frame of Project Contract Pol-Nor/197511/40/2013, CDOM-HEAT, and the Ocean Acidification Flagship program within the FRAM- High North Research Centre for Climate and the Environment, Norway
Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ic
publishedVersio
DEAD-Box Protein Ddx46 Is Required for the Development of the Digestive Organs and Brain in Zebrafish
Spatially and temporally controlled gene expression, including transcription, several mRNA processing steps, and the export of mature mRNA to the cytoplasm, is essential for developmental processes. It is well known that RNA helicases of the DExD/H-box protein family are involved in these gene expression processes, including transcription, pre-mRNA splicing, and rRNA biogenesis. Although one DExD/H-box protein, Prp5, a homologue of vertebrate Ddx46, has been shown to play important roles in pre-mRNA splicing in yeast, the in vivo function of Ddx46 remains to be fully elucidated in metazoans. In this study, we isolated zebrafish morendo (mor), a mutant that shows developmental defects in the digestive organs and brain, and found that it encodes Ddx46. The Ddx46 transcript is maternally supplied, and as development proceeds in zebrafish larvae, its ubiquitous expression gradually becomes restricted to those organs. The results of whole-mount in situ hybridization showed that the expression of various molecular markers in these organs is considerably reduced in the Ddx46 mutant. Furthermore, splicing status analysis with RT-PCR revealed unspliced forms of mRNAs in the digestive organ and brain tissues of the Ddx46 mutant, suggesting that Ddx46 may be required for pre-mRNA splicing during zebrafish development. Therefore, our results suggest a model in which zebrafish Ddx46 is required for the development of the digestive organs and brain, possibly through the control of pre-mRNA splicing
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