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Geographic information systems to support the ecosystem approach to fisheries : status, opportunities and challenges
Fabio Carocci, G. Bianchi, Paul Eastwood, Geoffery J. Meaden, 2009

Opis: The ecosystem approach to fisheries (EAF) has been developed during the last decade in response to perceived and actual deficiencies in previous methods of management. The EAF recognizes that fish are only one albeit important part of a much wider ecosystem incorporating an array of physical and biological components that humans interact with and exploit. Rather than managing single fish stocks, an EAF is concerned with the impacts of fisheries on the marine ecosystem, the interactions between different fisheries, of fisheries with the aquaculture sector, as well as with other human activities. The Geographic Information System (GIS) is considered an ideal platform upon which to perform necessary information management and decision-support analysis for the implementation of an EAF. This technical paper is primarily intended to be a guide to methods that readers could adopt for their own use of GIS for an EAF and these methods are covered in some detail. The planning considerations for an appropriate GIS in terms of objectives, scope and geographical area are outlined. The practical considerations are discussed and include hardware architecture, various software possibilities, sources and types of data that will be needed, and the array of backup and support that is available. More specifically, in Section 1 of this paper, the conceptual basis underlying EAF is discussed. In Section 2, a four-step participatory ecosystem management planning and implementation process consistent with EAF is recommended by the Food and Agriculture Organization of the United Nations (FAO) and includes: (i) scoping for issues, (ii) setting objectives, (iii) formulating rules and (iv) establishing a monitoring, assessment and review system. In Section 3, the use of GIS is examined beginning with a brief look at its history and development and then reviewing its current application and uses within marine fisheries. In Section 4, the potential use of GIS in a wide range of EAF-related projects is illustrated using examples that focus on mapping, modelling, management and communication. The degree to which GIS is currently being used for EAF implementation is illustrated by four case studies detailed in Section 5. Section 6 proposes a plan for implementation of an EAF using GIS and considers the challenges faced by developing countries in using GIS in fisheries management. Strategies to enhance the role of GIS in EAF are suggested. In conclusion, Section 7 makes recommendations for the adoption of GIS for EAF. The adoption of GIS for an EAF is no easy task and a number of challenges must be faced but GIS for EAF is feasible even in relatively resource-poor situations. The authors hope this paper encourages fishery managers and researchers to explore the many benefits of GIS for managing fisheries in an ecosystem context.
Objavljeno: 05.06.2012; Ogledov: 546; Prenosov: 25
URL Povezava na celotno besedilo

Alignment of carbon nanotubes in nematic liquid crystals
Paul van der Schoot, Vlad Popa-Nita, Samo Kralj, 2008, izvirni znanstveni članek

Opis: The self-organizing properties of nematic liquid crystals can be used to aligncarbon nanotubes dispersed in them. Because the nanotubes are so much thinner than the elastic penetration length, the alignment is caused by the coupling of the unperturbed director field to the anisotropic interfacial tension of the nanotubes in the nematic host fluid. In order to relate the degree of alignment of the nanotubes to the properties of the nematic liquid crystal, we treat the two components on the same footing and combine Landau-deGennes free energies for the thermotropic ordering of the liquid crystal and for the lyotropic nematic ordering of carbon nanotubes caused by their mutually excluded volumes. The phase ordering of the binary mixture is analyzed as a function of the volume fraction of the carbon nanotubes, the strength of the coupling and the temperature. We find that the degree of ordering of the nanorods is enslaved by the properties of the host liquid and that it can be tuned by raising or lowering the temperature or by increasing or decreasing their concentration. By comparing the theory to recent experiments, we find the anchoring energy of multiwalled carbon nanotubes to be in the range from 10-10 to 10-7 N m-1.
Ključne besede: liquid crystals, nematic crystals, molecular dynamics, stability, elasticity, carbon nanotubes
Objavljeno: 07.06.2012; Ogledov: 945; Prenosov: 33
URL Povezava na celotno besedilo

Influence of a random field on particle fractionation and solidification in liquid-crystal colloid mixtures
Vlad Popa-Nita, Paul van der Schoot, Samo Kralj, 2006, izvirni znanstveni članek

Opis: The influence of a random-anisotropy (RA) type disorder on the phase separation of nematogen-colloid mixtures is studied theoretically by combiningthe phenomenological Landau-de Gennes, Carnahan-Starling, and hard-sphere crystal theories. We assume that the colloids enforce the RA disorder on the surrounding thermotropic liquid-crystal (LC) molecules. We adopt the Imry-Ma argument according to which the lower-temperature phase exhibits a domain-type pattern. The colloids impose a finite degree of orientational ordering even in the isotropic (paranematic) phase. In the ordered phase they give rise to a domain-type structure, resulting in the distorted nematic (speronematic) phase. The RA field opposes the phase separation tendency. With increasing disorder the difference between the paranematic and speronematic ordering decreases. Consequently there is a critical disorder, above which both phases become identical from the orientation point of view, but have different concentrations of colloids. We have also estimated another characteristic value of disorder above which the isotropic phase can exist only in a liquid state, the crystal phase being suppressed completely.
Ključne besede: liquid crystals, transitions, segregation, mixing, random fields, solidification, complex fluids
Objavljeno: 07.06.2012; Ogledov: 684; Prenosov: 48
URL Povezava na celotno besedilo

Lipid layers on polyelectrolyte multilayer supports
Martin Fischlechner, Markus Zaulig, Stefan Meyer, Irina Estrela-Lopis, Luis Cuéllar, Joseba Irigoyen, Paula Pescador, Milan Brumen, Paul Messner, Sergio Moya, Edwin Donath, 2008, izvirni znanstveni članek

Opis: The mechanism of formation of supported lipid layers from phosphatidylcholine and phosphatidylserine vesicles in solution on polyelectrolyte multilayers was studied by a variety of experimental techniques. The interaction of zwitterionic and acidic lipid vesicles, as well as their mixtures, with polyelectrolyte supports was followed in real time by micro-gravimetry. The fabricated lipid-polyelectrolyte composite structures on top of multilayer coated colloidal particles were characterized by flow cytometry and imaging techniques. Lipid diffusion over the macroscopic scale was quantified by fluorescence recovery after photobleaching, and the diffusion was related to layer connectivity. The phospholipid-polyelectrolyte binding mechanism was investigated by infrared spectroscopy. A strong interaction of polyelectrolyte primary amino groups with phosphate and carboxyl groups of the phospholipids, leading to dehydration, was observed. Long-range electrostatic attraction was proven to be essential for vesicle spreading and rupture. Fusion of lipid patches into a homogeneous bilayer required lateral mobility of the lipids on the polyelectrolyte support. The binding of amino groups to the phosphate group of the zwitterionic lipids was too weak to induce vesicle spreading, but sufficient for strong adsorption. Only the mixture of phosphatidylcholine and phosphatidylserine resulted in the spontaneous formation of bilayers on polyelectrolyte multilayers. The adsorption of phospholipids onto multilayers displaying quarternary ammonium polymers produced a novel 3D lipid polyelectrolyte structure on colloidal particles.
Ključne besede: biophysics, lipids, lipid layers, electrolytes, multilayer supports
Objavljeno: 07.06.2012; Ogledov: 630; Prenosov: 30
URL Povezava na celotno besedilo

Similarities and differences of health-promoting leadership and transformational leadership
Anita Dunkl, Paul Jiménez, Simona Šarotar Žižek, Borut Milfelner, Wolfgang Kallus, 2015, izvirni znanstveni članek

Opis: The concept of health-promoting leadership focuses on the interaction between the organization and the individual by identifying components able to positively influence employees’ working conditions. In the present study, the effects of health-promoting leadership and transformational leadership on the employees’ recovery–stress balance are investigated. In an online study, 212 Slovenian workers were asked about their perceptions of their direct supervisors and their work-related stress and recovery. The results showed that both leadership styles have a significant effect on employees’ recovery at the workplace, which mediated the relationship between leadership and work-related stress.
Ključne besede: conditions, health-promoting leadership, transformational leadership, stress, recovery, working environment
Objavljeno: 03.04.2017; Ogledov: 315; Prenosov: 159
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