Entrepreneurial advantages and disadvantages of belonging     

Henrik Egbert 《GeoJournal》1998,46(2):129-134

The article analyzes the influence of religious network structures on entrepreneurial success. Members of the religious community of the Bohras in Tanga, Tanzania, are contrasted with entrepreneurs of other ethnic origins. It is shown that the religious network provides, through a loan scheme, the opportunities to start and run a business successfully. In this respect, the importance of the Islamic business ethic is underlined. Finally, the macro-economic effects of the network are outlined. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Natura 2000 sites and fisheries in German offshore waters     

Pedersen  Soren Anker; Fock  Heino; Krause  Jochen; Pusch  Christian; Sell  Anne L.; Bottcher  Uwe; Rogers  Stuart I.; Skold  Mattias; Skov  Henrik; Podolska  Magdalena; Piet  Gerjan J.; Rice  Jake C. 《ICES Journal of Marine Science》2009,66(1):155-169

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A non‐collisional,accretionary Sveconorwegian orogen     

Trond Slagstad  Nick M. W. Roberts  Mogens Marker  Torkil S. Røhr  Henrik Schiellerup 《地学学报》2013,25(1):30-37

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International fisheries regime effectiveness—Activities and resources of key actors in the Southern Ocean     

Örjan Bodin  Henrik Österblom 《Global Environmental Change》2013,23(5):948-956

Many contemporary environmental challenges are truly global and span several organizational and geographical borders. Research on international environmental regimes has, over the last couple of decades, identified several important factors that contribute to a more effective governance of global ecological resources, but few studies have addressed the different roles certain influential individual organizations play in determining regime effectiveness. Here we address this question by studying a relatively successful fishery governance system in the Southern Ocean. By drawing on insights from the research fields of common-pool resource management and international environmental regimes, we demonstrate that organizations engaged in certain combinations of activities, and that have access to certain combinations of resources stand out as important for regime effectiveness. In particular, collaboration with other flag states and being politically well-connected stand out as important explanatory factors. However, access to advanced technology, engagement in public campaigns, and being active in the field are other factors that, in different combinations, also seem to explain organizational importance. Furthermore, governmental and non-governmental organizations tend to perform different sets of activities and possess different resources, thereby complementing each other. Also, organizations doing similar things are often of different types with different mandates and objectives. This could contribute to improved adaptability and responsiveness to change at the larger regime level. Finally, we discuss some potential implications of our results for capacity-building in international environmental governance.  相似文献   

Surface exposure dating reveals MIS-3 glacial maximum in the Khangai Mountains of Mongolia     

Henrik Rother  Frank Lehmkuhl  David Fink  Veit Nottebaum 《Quaternary Research》2014

This study presents results from geomorphological mapping and cosmogenic radionuclide dating (¹⁰Be) of moraine sequences at Otgon Tenger (3905 m), the highest peak in the Khangai Mountains (central Mongolia). Our findings indicate that glaciers reached their last maximum extent between 40 and 35 ka during Marine Oxygen Isotope Stage (MIS) 3. Large ice advances also occurred during MIS-2 (at ~ 23 and 17–16 ka), but these advances did not exceed the limits reached during MIS-3. The results indicate that climatic conditions during MIS-3, characterized by a cool-wet climate with a greater-than-today input from winter precipitation, generated the most favorable setting for glaciation in the study region. Yet, glacial accumulation also responded positively to the far colder and drier conditions of MIS-2, and again during the last glacial–interglacial transition when precipitation levels increased. Viewed in context of other Pleistocene glacial records from High Asia, the pattern of glaciation in central Mongolia shares some features with records from southern Central Asia and NE-Tibet (i.e. ice maxima during interstadial wet phases), while other features of the Mongolian record (i.e. major ice expansion during the MIS-2 insolation minimum) are more in tune with glacier responses known from Siberia and western Central Asia.  相似文献   

How contact metamorphism can trigger global climate changes: Modeling gas generation around igneous sills in sedimentary basins   总被引：2，自引：0，他引：2  

Ingrid Aarnes  Henrik Svensen  Yuri Y. Podladchikov 《Geochimica et cosmochimica acta》2010,74(24):7179-7195

Large volumes of greenhouse gases such as CH₄ and CO₂ form by contact metamorphism of organic-rich sediments in aureoles around sill intrusions in sedimentary basins. Thermogenic gas generation and dehydration reactions in shale are treated numerically in order to quantify basin-scale devolatilization. We show that aureole thicknesses, defined as the zone of elevated metamorphism relative to the background level, vary within 30-250% of the sill thickness, depending on the temperature of the host-rock and intrusion, besides the sill thickness. In shales with total organic carbon content of >5 wt.%, CH₄ is the dominant volatile (85-135 kg/m³) generated through organic cracking, relative to H₂O-generation from dehydration reactions (30-110 kg/m³). Even using conservative estimates of melt volumes, extrapolation of our results to the scale of sill complexes in a sedimentary basin indicates that devolatilization can have generated ∼2700-16200 Gt CH₄ in the Karoo Basin (South Africa), and ∼600-3500 Gt CH₄ in the Vøring and Møre basins (offshore Norway). The generation of volatiles is occurring on a time-scale of 10-1000 years within an aureole of a single sill, which makes the rate of sill emplacement the time-constraining factor on a basin-scale. This study demonstrates that thousands of gigatons of potent greenhouse gases like methane can be generated during emplacement of Large Igneous Provinces in sedimentary basins.  相似文献   

Basic physiological biomarkers in adult female perch (Perca fluviatilis) in a chronically polluted gradient in the Stockholm recipient (Sweden)     

Linderoth M  Hansson T  Liewenborg B  Sundberg H  Noaksson E  Hanson M  Zebühr Y  Balk L 《Marine pollution bulletin》2006,53(8-9):437-450

By measuring a battery of basic physiological biomarkers and the concentration of SigmaDDT in adult female perch (Perca fluviatilis), an assumed aquatic pollution gradient was confirmed, with the city of Stockholm (Sweden) as a point source of anthropogenic substances. The investigation included an upstream gradient, westwards through Lake M?laren (46 km), and a downstream gradient, eastwards through the Stockholm archipelago (84 km). The results indicated a severe pollution situation in central Stockholm, with poor health status of the perch: retarded growth, increased frequency of sexually immature females, low gonadosomatic index, and disturbed visceral fat metabolism. SigmaDDT, measured as a pollution indicator, was 10-28 times higher than the background in perch from the Baltic Proper. Besides the main gradient other sources of pollution also influenced the response pattern of the measured biomarkers. In particular, there were strong indications of pollution coming from the Baltic Sea.  相似文献   

Estimated energy balance in the jovian upper atmosphere during an auroral heating event     

Henrik Melin  Tom Stallard  Denis Grodent 《Icarus》2006,181(1):256-265

We present an analysis of a series of observations of the auroral/polar regions of Jupiter, carried out between September 8 and 11, 1998, making use of the high-resolution spectrometer, CSHELL, on the NASA InfraRed Telescope Facility (IRTF), Mauna Kea, Hawaii; these observations spanned an “auroral heating event.” This analysis combines the measured line intensities and ion velocities with a one-dimensional model vertical profile of the jovian thermosphere/ionosphere. We compute the model line intensities both assuming local thermodynamic equilibrium (LTE) and, relaxing this condition (non-LTE), through detailed balance calculations, in order to compare with the observations. Taking the model parameters derived, we calculate the changes in heating rate required to account for the modelled temperature profiles that are consistent with the measured line intensities. We compute the electron precipitation rates required to give the modelled ion densities that are consistent with the measured line intensities, and derive the corresponding Pedersen conductivities. We compute the changes in heating due to Joule heating and ion drag derived from the measured ion velocities, and modelled conductivities, making use of ion-neutral coupling coefficients derived from a 3-D global circulation model. Finally, we compute the cooling due to the downward conduction of heat and the radiation-to-space from the molecular ion and hydrocarbons. Comparison of the various heating and cooling terms enables us to investigate the balance of energy inputs into the auroral/polar atmosphere. Increases in Joule heating and ion drag are sufficient to explain the observed heating of the atmosphere; increased particle precipitation makes only a minor heating contribution. But local cooling effects—predominantly radiation-to-space—are shown to be too inefficient to allow the atmosphere to relax back to pre-event thermal conditions. Thus we conclude that this event provides observational, i.e. empirical, evidence that heat must be transported away from the auroral/polar regions by thermally or mechanically driven winds.  相似文献   

The linear stability of dilute particulate rings     

Henrik N. Latter  Gordon I. Ogilvie 《Icarus》2006,184(2):498-516

Irregular structure in planetary rings is often attributed to the intrinsic instabilities of a homogeneous state undergoing Keplerian shear. Previously these have been analysed with simple hydrodynamic models. We instead employ a kinetic theory, in which we solve the linearised moment equations derived in Shu and Stewart 1985 for a dilute ring. This facilitates an examination of velocity anisotropy and non-Newtonian stress, and their effects on the viscous and viscous/gravitational instabilities thought to occur in Saturn's rings. Because we adopt a dilute gas model, the applicability of our results to the actual dense rings of Saturn are significantly curtailled. Nevertheless this study is a necessary preliminary before an attack on the difficult problem of dense ring dynamics. We find the Shu and Stewart formalism admits analytic stability criteria for the viscous overstability, viscous instability, and thermal instability. These criteria are compared with those of a hydrodynamic model incorporating the effective viscosity and cooling function computed from the kinetic steady state. We find the two agree in the ‘hydrodynamic limit’ (i.e., many collisions per orbit) but disagree when collisions are less frequent, when we expect the viscous stress to be increasingly non-Newtonian and the velocity distribution increasingly anisotropic. In particular, hydrodynamics predicts viscous overstability for a larger portion of parameter space. We also numerically solve the linearised equations of the more accurate Goldreich and Tremaine 1978 kinetic model and discover its linear stability to be qualitatively the same as that of Shu and Stewart's. Thus the simple collision operator adopted in the latter would appear to be an adequate approximation for dilute rings, at least in the linear regime.  相似文献   

From modelling theory to policy: lessons from the LCS project     

Henrik Hammar  Sverker C. Jagers 《Climate Policy》2013,13(6):613-625

The Low-Carbon Society (LCS) research project (Strachan et al., 2008) is to be congratulated for providing a rich, useful source of models to inform and precipitate discussion of policy options for moving towards a low-carbon society. This commentary explores additional considerations that warrant inclusion in any policy discussion: the feasibility of political will and leadership, the limitations of technical feasibility, and clarity about what ‘the price of carbon’ means. Difficulties exist with establishing carbon prices due to differences in energy prices between countries and the distinction between baseline (existing policies) and additional parts. An alternative may be to place more emphasis on the energy price for mitigation, along with other indicators (energy efficiency, carbon intensity, renewable power diffusion) for comparison. A policy is proposed, based on the energy price combined with an emphasis on accelerating technological innovation and overcoming barriers to the adoption of energy efficiency measures.  相似文献