2,716 research outputs found
Schur Polynomials and the Yang-Baxter equation
We show that within the six-vertex model there is a parametrized Yang-Baxter
equation with nonabelian parameter group GL(2)xGL(1) at the center of the
disordered regime. As an application we rederive deformations of the Weyl
character formule of Tokuyama and of Hamel and King.Comment: Revised introduction; slightly changed reference
Hypoxia in the York River, 1991
This data report describes field studies conducted during the summer of 1991 by the Virginia Institute of Marine Science (VIMS) when both the physical environment and the dissolved oxygen regime were monitored, with the objective of better understanding how physical transport processes affect DO. The 1991 data sets will be presented here. Analysis and interpretation of the data is the subject of other scientific reports
Stormwater Management Adaptation Pathways under Climate Change and Urbanization
Urban runoff volumes and flow peaks are likely to increase in the future owing to climate change-driven effects on rainfall and continued urbanization. Actionable planning estimates that anticipate these impacts are needed to assess stormwater management infrastructure requirements and to minimize impacts on ecosystem services. This study presents a planning-level simple flow simulation tool and quantifies benefits of green stormwater management practices in small watersheds. Flow simulation was performed using a curve number-based watershed model (CWM). A portfolio approach was used to assess cost-optimal stormwater adaptation pathways considering a suite of alternative practices including both gray and green infrastructure. The CWM provides actionable information for medium to highly urbanized watersheds with percent bias less than 30% for highly urbanized watersheds. Considering projected future stormwater needs, analysis of multiple stormwater management approaches showed that green stormwater management alternatives are less cost-optimal than gray infrastructure at small watershed scales. These results suggest the possible use of CWM for quick planning-level flow estimates and analysis of more green practices for cost-optimal alternatives
Developing a life story: Constructing relations between self and experience in autobiographical narratives
Abstract In this paper, we consider how the life story develops through the creation of selfevent connections in narrating experiences. We first outline the ways in which such connections have been implied by existing work on the life story, and then consider the varieties of such connections that we see in our own work. That work suggests that selfevent connections can construct both a stable sense of self as well as a sense of how the self has changed across time. Moreover, different types of connections have different implications for the development of the life story. We also consider developmental and other factors which make one or another type of connection more likely. Finally, we consider two issues for future work, as well as some methodological considerations involved in testing those proposals. Copyright © 2007 S. Karger AG, Basel How do we know that we are the same person over time? This problem, termed in philosophy the problem of personal identity, remains current in both philosoph
Application of advanced technologies to small, short-haul aircraft
The results of a preliminary design study which investigates the use of selected advanced technologies to achieve low cost design for small (50-passenger), short haul (50 to 1000 mile) transports are reported. The largest single item in the cost of manufacturing an airplane of this type is labor. A careful examination of advanced technology to airframe structure was performed since one of the most labor-intensive parts of the airplane is structures. Also, preliminary investigation of advanced aerodynamics flight controls, ride control and gust load alleviation systems, aircraft systems and turbo-prop propulsion systems was performed. The most beneficial advanced technology examined was bonded aluminum primary structure. The use of this structure in large wing panels and body sections resulted in a greatly reduced number of parts and fasteners and therefore, labor hours. The resultant cost of assembled airplane structure was reduced by 40% and the total airplane manufacturing cost by 16% - a major cost reduction. With further development, test verification and optimization appreciable weight saving is also achievable. Other advanced technology items which showed significant gains are as follows: (1) advanced turboprop-reduced block fuel by 15.30% depending on range; (2) configuration revisions (vee-tail)-empennage cost reduction of 25%; (3) leading-edge flap addition-weight reduction of 2500 pounds
Development of FTK architecture: a fast hardware track trigger for the ATLAS detector
The Fast Tracker (FTK) is a proposed upgrade to the ATLAS trigger system that
will operate at full Level-1 output rates and provide high quality tracks
reconstructed over the entire detector by the start of processing in Level-2.
FTK solves the combinatorial challenge inherent to tracking by exploiting the
massive parallelism of Associative Memories (AM) that can compare inner
detector hits to millions of pre-calculated patterns simultaneously. The
tracking problem within matched patterns is further simplified by using
pre-computed linearized fitting constants and leveraging fast DSP's in modern
commercial FPGA's. Overall, FTK is able to compute the helix parameters for all
tracks in an event and apply quality cuts in approximately one millisecond. By
employing a pipelined architecture, FTK is able to continuously operate at
Level-1 rates without deadtime. The system design is defined and studied using
ATLAS full simulation. Reconstruction quality is evaluated for single muon
events with zero pileup, as well as WH events at the LHC design luminosity. FTK
results are compared with the tracking capability of an offline algorithm.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
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Essential role of syntaxin-binding protein-1 in the regulation of glucagon-like peptide-1 secretion
Circadian secretion of the incretin, glucagon-like peptide-1 (GLP-1), correlates with expression of the core clock gene, Bmal1, in the intestinal L-cell. Several SNARE proteins known to be circadian in pancreatic α- and β-cells are also necessary for GLP-1 secretion. However, the role of the accessory SNARE, Syntaxin binding protein-1 (Stxbp1; also known as Munc18-1) in the L-cell is unknown. The aim of this study was to determine whether Stxbp1 is under circadian regulation in the L-cell and its role in the control of GLP-1 secretion. Stxbp1 was highly-enriched in L-cells, and STXBP1 was expressed in a subpopulation of L-cells in mouse and human intestinal sections. Stxbp1 transcripts and protein displayed circadian patterns in mGLUTag L-cells line, while chromatin-immunoprecipitation revealed increased interaction between BMAL1 and Stxbp1 at the peak time-point of the circadian pattern. STXBP1 recruitment to the cytosol and plasma membrane within 30 minutes of L-cell stimulation was also observed at this time-point. Loss of Stxbp1 in vitro and in vivo led to reduced stimulated GLP-1 secretion at the peak time-point of circadian release, and impaired GLP-1 secretion ex vivo. In conclusion, Stxbp1 is a circadian regulated exocytotic protein in the intestinal L-cell that is an essential regulatory component of GLP-1 secretion.Wellcome Trust
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