Spatial continuity of measured seawater and tracer fluxes through Nares Strait, a dynamically wide channel bordering the Canadian Archipelago

Freshwater delivered as precipitation and runoff to the North Pacific and Arctic oceans returns to the Atlantic principally via the Canadian polar shelf and Fram Strait. It is conveyed as ice or freshened seawater. Here we use detailed ship-based measurements to calculate a snap-shot of volume, freshwater, and tracer fluxes through Nares Strait, a 500-km long waterway separating Greenland and Ellesmere Island. We use quasi-synoptic observations of current by ship-mounted acoustic Doppler current profiler (ADCP), of salinity and temperature by CTD probe and of dissolved nutrients by rosette bottle sampler on four cross-sections between 82 and 78N latitude. Data were collected during the first half of August 2003. We partition the fluxes into components derived from Pacific and Atlantic inflows into the Arctic Ocean. During the time of the survey, there was a net southward 0.91±0.10 Sv (106 m3 s-1) flux of volume and a net southward 31±4 10-3 Sv (977±127 km3 y-1) flux of freshwater relative to a salinity of 34.8. Much of the volume flux was carried within a strong (40 cm s-1), narrow (10 km) subsurface jet hugging the western (Ellesmere Island) side of the strait. The presence of this jet in four sections spanning the 500-km length of the strait is evidence of a buoyant boundary current through the strait. The jet was coincident with elevated concentrations of phosphate (1.0 mmol m-3) and silicate (11 mmol m-3) which both indicate a Pacific Ocean source. We interpreted the ratio of dissolved total inorganic nitrogen to phosphate in terms of fractional dilution of Atlantic by Pacific waters. About 0.43±0.10 Sv (39%) of the southward flow was of Pacific origin. These results are a snapshot during the summer of 2003 following a prolonged period of northward directed wind stress when ice cover was mobile. Although long-term mean values are likely different, we determined that the major fraction of the through-flow is carried by a jet of scale determined by the internal Rossby radius (5-10 km)

Aktuelle Reformvorschläge zur EU-Sozialpolitik - von der Kontroverse zum scheinbaren Konsens?

'Die aktuellen Vorschläge zur Reform und Weiterentwicklung der EU-Sozialpolitik sind geprägt von zumindest oberflächlichem Konsens über die Herausforderungen für, die Ziele und Mittel sowie über die Form der Umsetzung von EU-Sozialpolitik. Der Artikel erklärt diese - im Vergleich zur konfliktträchtigen Debatte in der Vergangenheit - verhältnismäßig konsensuale Situation mit vier Faktoren: Erstens wurden bereits viele sozialpolitische Materien auf EU-Ebene relativ erfolgreich geregelt. Zweitens bewegt sich EU-Sozialpolitik zwar in kleinen Schritten, aber doch. Drittens entpolitisierten Formelkompromisse die Debatte. Und viertens wurden sozialpolitisch relevante Entscheidungen auf die wirtschaftspolitische Arena und die Gerichte verlagert. Aufsehenerregende EuGH-Urteile aus dem Jahr 2007 könnten mittelfristig zu einer Re-Politisierung der EU-Sozialpolitik führen. Angesichts unterschiedlicher Denkmodelle sowie sozialer und arbeitsrechtlicher Niveaus in den Mitgliedstaaten ist aber nicht zu erwarten, dass über Formelkompromisse hinausgehende Lösungen leicht zu erringen sein werden.' (Autorenreferat)'Current reform proposals in the field of EU social policy are characterised, at least at the surface, by rather consensual views. This refers to the challenges, the overall goals and instruments, and the ways how to implement social policy. Whereas discussions can be characterised by harsh controversies in the past, four factors explain the consensual character of most reform proposals: First, many social standards have indeed already been agreed upon at EU level. Second, while it is true that EU social policy has only been developed incrementally, it still has been moving. Third, there are certain compromise formulae that depoliticised the relevant discourse. Finally, crucial issues of social and labour law have been transferred to the (politico-) economic and judicial arenas. Considering some remarkable decisions of the European Court of Justice in 2007, it is to be expected that EU social policy may be repoliticised. However, cleavages in policy paradigms, social standards and industrial law will make solutions beyond compromise formulae rather difficult.' (author's abstract)

OpenReq: recommender systems in requirements engineering

The major focus of OpenReq is the development of recommendation and decision technologies that effciently support requirements engineering processes in large and distributed software projects. Example scenarios thereof are the bid management in industrial systems, requirements engineering in cross-plattform open source software development, and requirements management in large user communities (telecommunications sector). The aim of this paper is to provide an overview of OpenReq and to provide insights into related application scenarios and research issues.Peer ReviewedPostprint (published version

(Re)configuration based on model generation

Reconfiguration is an important activity for companies selling configurable products or services which have a long life time. However, identification of a set of required changes in a legacy configuration is a hard problem, since even small changes in the requirements might imply significant modifications. In this paper we show a solution based on answer set programming, which is a logic-based knowledge representation formalism well suited for a compact description of (re)configuration problems. Its applicability is demonstrated on simple abstractions of several real-world scenarios. The evaluation of our solution on a set of benchmark instances derived from commercial (re)configuration problems shows its practical applicability.Comment: In Proceedings LoCoCo 2011, arXiv:1108.609

Identifying requirements in requests for proposal

Abstract. [Context & motivation] Bidding processes are a usual requirement elicitation instrument for large IT or infrastructure projects. An organization or agency issues a Request for Proposal (RFP) and interested companies may submit compliant offers. [Problem] Such RFPs comprise natural language documents of several hundreds of pages with requirements of various kinds mixed with other information. The analysis of that huge amount of information is very time consuming and cumbersome because bidding companies should not disregard any requirement stated in the RFP. [Principal ideas/results] This research preview paper presents a first version of a classification component, OpenReq Classification Service (ORCS), which extracts requirements from RFP documents while discarding irrelevant text. ORCS is based on the use of Naïve Bayes classifiers. We have trained ORCS with 6 RFPs and then tested the component with 4 other RFPs, all of them from the railway safety domain. [Contribution] ORCS paves the way to improved productivity by reducing the manual effort needed to identify requirements from natural language RFPsPeer ReviewedPostprint (author's final draft

An Observational Estimate of Volume and Freshwater Flux Leaving the Arctic Ocean through Nares Strait

The Arctic Ocean is an important link in the global hydrological cycle, storing freshwater and releasing it to the North Atlantic Ocean in a variable fashion as pack ice and freshened seawater. An unknown fraction of this return flow passes through Nares Strait between northern Canada and Greenland. Surveys of ocean current and salinity in Nares Strait were completed in the summer of 2003. High-resolution data acquired by ship-based acoustic Doppler current profiler and via hydrographic casts revealed subtidal volume and freshwater fluxes of 0.8 ± 0.3 Sv and –25 ± 12 mSv (Sv = 10³ mSv = 10⁶ m³ s⁻¹), respectively. The observations resolved the dominant spatial scale of variability, the internal Rossby radius of deformation (L[subscript]D ~9 km), and revealed a complex, yet coherent along-channel flow with a Rossby number of about 0.13, close to geostrophic balance. Approximately one-third of the total volume flux was associated with across-channel slope of the sea surface and two-thirds (68%) with across-channel slope of isopycnal surfaces. During the period of observation, sustained wind from the southwest weakened the average down-channel flow at the surface. The speed of tidal currents exceeded subtidal components by a factor of 2. Tidal signals were resolved and removed from the observations here using two independent methods resolving horizontal and vertical variability of tidal properties, respectively. Tidal current predictions from a barotropic model agreed well with depth-averaged observations in both amplitude and phase. However, because estimates of freshwater flux require accurate surface currents (and salinity), a least squares fitting procedure using velocity data was judged more reliable, since it permits quantification of vertical tidal current variations

A multivariable miRNA signature delineates the systemic hemodynamic impact of arteriovenous shunt placement in a pilot study

Arteriovenous (AV) fistulas for hemodialysis can lead to cardiac volume loading and increased serum brain natriuretic peptide (BNP) levels. Whether short-term AV loop placement in patients undergoing microsurgery has an impact on cardiac biomarkers and circulating microRNAs (miRNAs), potentially indicating an increased hemodynamic risk, remains elusive. Fifteen patients underwent AV loop placement with delayed free flap anastomosis for microsurgical reconstructions of lower extremity soft-tissue defects. N-terminal pro-BNP (NT-proBNP), copeptin (CT-proAVP), and miRNA expression profiles were determined in the peripheral blood before and after AV loop placement. MiRNA expression in the blood was correlated with miRNA expression from AV loop vascular tissue. Serum NT-proBNP and copeptin levels exceeded the upper reference limit after AV loop placement, with an especially strong NT-proBNP increase in patients with preexistent cardiac diseases. A miRNA signature of 4 up-regulated (miR-3198, miR-3127-5p, miR-1305, miR-1288-3p) and 2 down-regulated miRNAs (miR30a-5p, miR-145-5p) which are related to cardiovascular physiology, showed a significant systemic deregulation in blood and venous tissue after AV loop placement. AV loop placement causes serum elevations of NT-proBNP, copeptin as well as specific circulating miRNAs, indicating a potentially increased hemodynamic risk for patients with cardiovascular comorbidities, if free flap anastomosis is delayed

MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

Background: Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investi‑ gated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic efects on miRNA and gene expression profles over time. Methods: AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoan‑ giogenesis was confrmed by histologic analysis and micro-computed tomography. MiRNA and gene expression pro‑ fles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymer‑ ase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry. Results: Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenationassociated genes (HIF1A, HMOX1), and angiopoetic growth factors. Signifcant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C–X–C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confrmed at the protein level by immunohistochemistry. Conclusions: Our data indicate that fow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP

MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

Background: Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investigated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic effects on miRNA and gene expression profiles over time. Methods: AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoangiogenesis was confirmed by histologic analysis and micro-computed tomography. MiRNA and gene expression profiles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymerase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry. Results: Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenation-associated genes (HIF1A, HMOX1), and angiopoetic growth factors. Significant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C–X–C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confirmed at the protein level by immunohistochemistry. Conclusions: Our data indicate that flow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP