scholarly journals AN OIL SPILL MODEL SYSTEM FOR ARCTIC WATERS

1989 ◽  
Vol 1989 (1) ◽  
pp. 517-523
Author(s):  
Malcolm Spaulding ◽  
Tatsusaburo Isaji ◽  
Katherine Jayko

ABSTRACT An Arctic coastal sea model system, consisting of submodels for weather, hydrodynamics, waves, suspended sediment, ice cover, oil spill trajectory and fates, and ecosystem dynamics is presented. The structure and operation of each sub-model and linkages among the various model components are briefly described. The weather, hydrodynamic, ice, and oil spill fates components of the model system are applied to predict hydrodynamics and oil spill trajectories from selected release points in the Bering Sea. Trajectory data are analyzed to describe the percent of trajectories affecting land and the direction, length, and duration distribution of trajectories. A detailed sensitivity study is performed to determine the role of the various mean current components and wind drift effects in describing spill trajectories. Model predictions highlight the importance of accurately representing the environmental data used as input to the model.

2010 ◽  
Vol 27 (1-2) ◽  
pp. 81-90
Author(s):  
Krishna Poudel

Mountains have distinct geography and are dynamic in nature compared to the plains. 'Verticality' and 'variation' are two fundamental specificities of the mountain geography. They possess distinct temporal and spatial characteristics in a unique socio-cultural setting. There is an ever increasing need for spatial and temporal data for planning and management activities; and Geo Information (GI) Science (including Geographic Information and Earth Observation Systems). This is being recognized more and more as a common platform for integrating spatial data with social, economic and environmental data and information from different sources. This paper investigates the applicability and challenges of GISscience in the context of mountain geography with ample evidences and observations from the mountain specific publications, empirical research findings and reports. The contextual explanation of mountain geography, mountain specific problems, scientific concerns about the mountain geography, advances in GIScience, the role of GIScience for sustainable development, challenges on application of GIScience in the contexts of mountains are the points of discussion. Finally, conclusion has been made with some specific action oriented recommendations.


Author(s):  
Ahmad Alaassar ◽  
Anne-Laure Mention ◽  
Tor Helge Aas

AbstractScholars and practitioners continue to recognize the crucial role of entrepreneurial ecosystems (EEs) in creating a conducive environment for productive entrepreneurship. Although EEs are fundamentally interaction systems of hierarchically independent yet mutually dependent actors, few studies have investigated how interactions among ecosystem actors drive the entrepreneurial process. Seeking to address this gap, this paper explores how ecosystem actor interactions influence new ventures in the financial technology (fintech) EE of Singapore. Guided by an EE framework and the use of an exploratory-abductive approach, empirical data from semi-structured interviews is collected and analyzed. The findings reveal four categories representing both the relational perspective, which features interaction and intermediation dynamics, and the cultural perspective, which encompasses ecosystem development and regulatory dynamics. These categories help explain how and why opportunity identification and resource exploitation are accelerated or inhibited for entrepreneurs in fintech EEs. The present study provides valuable contributions to scholars and practitioners interested in EEs and contributes to the academic understanding of the emerging fintech phenomenon.


1998 ◽  
Vol 9 (7) ◽  
pp. 1803-1816 ◽  
Author(s):  
Michael C. Brown ◽  
Joseph A. Perrotta ◽  
Christopher E. Turner

We have previously shown that the LIM domains of paxillin operate as the focal adhesion (FA)-targeting motif of this protein. In the current study, we have identified the capacity of paxillin LIM2 and LIM3 to serve as binding sites for, and substrates of serine/threonine kinases. The activities of the LIM2- and LIM3-associated kinases were stimulated after adhesion of CHO.K1 cells to fibronectin; consequently, a role for LIM domain phosphorylation in regulating the subcellular localization of paxillin after adhesion to fibronectin was investigated. An avian paxillin-CHO.K1 model system was used to explore the role of paxillin phosphorylation in paxillin localization to FAs. We found that mutations of paxillin that mimicked LIM domain phosphorylation accelerated fibronectin-induced localization of paxillin to focal contacts. Further, blocking phosphorylation of the LIM domains reduced cell adhesion to fibronectin, whereas constitutive LIM domain phosphorylation significantly increased the capacity of cells to adhere to fibronectin. The potentiation of FA targeting and cell adhesion to fibronectin was specific to LIM domain phosphorylation as mutation of the amino-terminal tyrosine and serine residues of paxillin that are phosphorylated in response to fibronectin adhesion had no effect on the rate of FA localization or cell adhesion. This represents the first demonstration of the regulation of protein localization through LIM domain phosphorylation and suggests a novel mechanism of regulating LIM domain function. Additionally, these results provide the first evidence that paxillin contributes to “inside-out” integrin-mediated signal transduction.


2007 ◽  
Vol 24 (2) ◽  
pp. 255-269 ◽  
Author(s):  
Sabine Philipps ◽  
Christine Boone ◽  
Estelle Obligis

Abstract Soil Moisture and Ocean Salinity (SMOS) was chosen as the European Space Agency’s second Earth Explorer Opportunity mission. One of the objectives is to retrieve sea surface salinity (SSS) from measured brightness temperatures (TBs) at L band with a precision of 0.2 practical salinity units (psu) with averages taken over 200 km by 200 km areas and 10 days [as suggested in the requirements of the Global Ocean Data Assimilation Experiment (GODAE)]. The retrieval is performed here by an inverse model and additional information of auxiliary SSS, sea surface temperature (SST), and wind speed (W). A sensitivity study is done to observe the influence of the TBs and auxiliary data on the SSS retrieval. The key role of TB and W accuracy on SSS retrieval is verified. Retrieval is then done over the Atlantic for two cases. In case A, auxiliary data are simulated from two model outputs by adding white noise. The more realistic case B uses independent databases for reference and auxiliary ocean parameters. For these cases, the RMS error of retrieved SSS on pixel scale is around 1 psu (1.2 for case B). Averaging over GODAE scales reduces the SSS error by a factor of 12 (4 for case B). The weaker error reduction in case B is most likely due to the correlation of errors in auxiliary data. This study shows that SSS retrieval will be very sensitive to errors on auxiliary data. Specific efforts should be devoted to improving the quality of auxiliary data.


2005 ◽  
Vol 119 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Gerrit T. S. Beemster ◽  
Steven Vercruysse ◽  
Lieven De Veylder ◽  
Martin Kuiper ◽  
Dirk Inzé

2013 ◽  
Vol 108 ◽  
pp. 110-119 ◽  
Author(s):  
Guillermo Orts-Gil ◽  
Kishore Natte ◽  
Raphael Thiermann ◽  
Matthias Girod ◽  
Steffi Rades ◽  
...  

1987 ◽  
Vol 87 (2) ◽  
pp. 357-362
Author(s):  
J. Gavrilovic ◽  
R.M. Hembry ◽  
J.J. Reynolds ◽  
G. Murphy

A specific antiserum to purified rabbit tissue inhibitor of metalloproteinases (TIMP) was raised in sheep, characterized and used to investigate the role of TIMP in a model system. Chondrocytes and endothelial cells cultured on 14C-labelled type I collagen films and stimulated to produce collagenase were unable to degrade the films unless the anti-TIMP antibody was added. The degradation induced was inhibited by a specific anti-rabbit collagenase antibody. It was concluded that TIMP is a major regulatory factor in cell-mediated collagen degradation.


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