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1.
Recent conversations concerning organic food systems have focused on the conventionalization hypothesis, which posits that
the organic food sector has become increasingly bifurcated between “historical” players in the organic movement on one side,
and on the other by distributors and industrial operators recently arrived in the sector, who practice a more conventionalized
form of organic agriculture which is now on the ascendancy. The most prominent explanations for the growth and dominance of
a conventionalized organic food system have been economic, based in the logics of input costs, especially land rent. We use
the cases of the Belgian Blue commodity system and the Belgian organic beef commodity system to argue that conventionalization
is also cognitive. To understand the role of cognition in the ascendance of the conventional organic food sector, we utilize
concept of “référentiel”—or system of cognitive references—as developed by Muller and Jobert. We believe that comparing organic and conventional practices as two systems of cognitive
references makes a deeper understanding of conventionalization possible in two ways: first because it makes it clear that
the two systems coexist on a cognitive level, understood in a broad sense as tightly knit sets of knowledges, beliefs, standards,
and images. Secondly, the concept of référentiel enables one to understand how the conventional system can become irreversible
(lock-in effect) and thus incompatible with the development of the organic system.
相似文献
| Pierre M. StassartEmail: |
2.
Joachim Kuhlemann Klaas van der Borg Paul D. Bons Martin Danišík Wolfgang Frisch 《International Journal of Earth Sciences》2008,97(3):549-564
A study of erosion rates by in-situ 10Be concentrations in granites of Miocene high-elevation paleosurfaces in Corsica indicates maximum erosion rates between 8
and 24 mm/kyear. The regional distribution of measured erosion rates indicates that the local climatic conditions, namely
precipitation, the petrographic composition of granites, and the degree of brittle deformation govern erosion rates. Chemical
erosion dominates even at elevations around 2,000 m in presently subalpine climate conditions. Field evidence indicates that
erosion operates by continuous dissolution and/or disintegration to grains (grusification). The erosion rates are relatively
high with respect to the preservation of inferred Early Miocene landscapes. We infer temporal burial in the Middle Miocene
and significantly lower erosion rates in the Neogene until ∼3 Ma to explain the preservation of paleosurfaces, in line with
fission track data. Valley incision rates that are a magnitude higher than erosion rates on summit surfaces result in relief
enhancement and long-term isostatic surface uplift. On the other hand, widening and deepening of valleys by cyclic glaciation
progressively destroys the summit surface relics.
相似文献
| Wolfgang FrischEmail: |
3.
This article explores the impacts of floods on the economy, environment, and society and tries to clarify the rural community’s
coping mechanism to flood disasters in Central Viet Nam. It focuses on the social aspects of flood risk perception that shapes
the responses to floods. The research findings revealed that flooding is an essential element for a coastal population, whose
livelihood depend on productive functions of cyclical floods. The findings also revealed that floods, causing losses and damages,
often inhibited economic development. The surveyed communities appeared to have evolved coping mechanisms to reduce the negative
impacts of the floods, yet these coping mechanisms are under pressure due to environmental degradation. Integrated flood risk
management is considered as a suitable paradigm for coping with flood disasters.
相似文献
| Phong TranEmail: |
4.
Boris Kolesov 《Physics and Chemistry of Minerals》2008,35(5):271-278
Single-crystal polarized Raman spectra (3,000–4,000 cm−1 at 3 ≤ T ≤ 300 K) were measured for synthetic alkali-free and natural beryl, Be2Al3Si6O18·xH2O, to determine the behavior of H2O molecules of both Type I and Type II in the cavities. At low temperature, the H2O molecules of Type I displace from the center of cavity and give rise to very weak hydrogen bonding with the host lattice.
The H2O Type I translational motion is characterized by substantial anharmonicity and looks like a motion of “a particle in the
box” with a frequency of 6.3 cm−1. Water Type II is characterized by a free rotation with respect to the C
2 molecule axis, and it makes possible the water nuclear isomers (i.e. ortho- and para-) to be observed at low temperature.
相似文献
| Boris KolesovEmail: |
5.
Dorian Speakman 《Natural Hazards》2008,44(1):111-127
A vulnerability index for the Fire Service in the UK has been designed to identify vulnerable locations during episodes of
severe floods. Taking recent case studies with the UK Fire Service, the patterns of vulnerability, in terms of demand on time
and resources, can be explained by investigating the environmental causes and their interaction with the adaptive capacity
of the response agencies.
相似文献
| Dorian SpeakmanEmail: |
6.
Climate change impacts on groundwater recharge- uncertainty, shortcomings, and the way forward? 总被引：1，自引：0，他引：1
I. P. Holman 《Hydrogeology Journal》2006,14(5):637-647
An integrated approach to assessing the regional impacts of climate and socio-economic change on groundwater recharge is described from East Anglia, UK. Many factors affect future groundwater recharge including changed precipitation and temperature regimes, coastal flooding, urbanization, woodland establishment, and changes in cropping and rotations.Important sources of uncertainty and shortcomings in recharge estimation are discussed in the light of the results. The uncertainty in, and importance of, socio-economic scenarios in exploring the consequences of unknown future changes are highlighted. Changes to soil properties are occurring over a range of time scales, such that the soils of the future may not have the same infiltration properties as existing soils. The potential implications involved in assuming unchanging soil properties are described.To focus on the direct impacts of climate change is to neglect the potentially important role of policy, societal values and economic processes in shaping the landscape above aquifers. If the likely consequences of future changes of groundwater recharge, resulting from both climate and socio-economic change, are to be assessed, hydrogeologists must increasingly work with researchers from other disciplines, such as socio-economists, agricultural modellers and soil scientists.
相似文献
| I. P. HolmanEmail: Phone: +44-(0)1525-863000Fax: +44-(0)1525-863344 |
7.
The present state-of-the-art for natech risk and management is discussed. Examples of recent natechs include catastrophic
oil spills associated with Hurricane Katrina and hazardous chemical releases in Europe during the heavy floods of 2002. Natechs
create difficult challenges for emergency responders due to the geographical extent of the natural disaster, the likelihood
of simultaneous releases, emergency personnel being preoccupied with response to the natural disaster, mitigation measures
failing due to the effects of the natural disaster, and others. Recovery from natechs may be much more difficult than for
“normal” chemical accidents, as the economic and social conditions of the industrial facility and the surrounding community
may have been drastically altered by the natural disaster. Potential safeguards against natechs include adoption of stricter
design criteria, chemical process safeguards, community land use planning, disaster mitigation and response planning, and
sustainable industrial processes, but these safeguards are only sporadically applied. Ultimately, the public must engage in
a comprehensive discussion of acceptable risks for natechs.
相似文献
| Ana Maria CruzEmail: |
8.
The irreversible water–rock mass exchanges leading to the production of the Fiume Grande valley (Calabria, Italy) stream waters
and groundwaters, starting from local rainwaters, were simulated through reaction path modeling in reaction progress (stoichiometric)
mode. The simulations assumed bulk dissolution of a phyllitic rock and calcite and precipitation of gibbsite, kaolinite, amorphous
silica, illite, a smectite solid mixture, a hydroxide solid mixture, and a trigonal carbonate solid mixture. The analytical
contents of major and trace elements in stream waters and groundwaters were satisfactorily reproduced. However, further investigations
are necessary to clarify the fate of As in this natural systems.
相似文献
| Rosanna De RosaEmail: |
9.
10.
Almost annually, natural hazards such as floods and landslides cause a great deal of financial loss and human suffering in
Taiwan. In order to gain a better understanding of disaster preparedness, this paper examines several factors in relation
to hazard mitigation behavior: social economic status (education, income), psychological vulnerability (sense of powerless
and helpless), risk perception (perceived impact and control) and social trust. The statistical analysis reported here is
based on the “2004 National Risk Perception Survey of Floods and Landslides in Taiwan”. The main findings include: (1) in
comparison with general public, victims are less willing to adopt risk mitigation measures than the public, even though they
perceive larger impacts, worry more about the hazard, and pay more attention to hazard information; (2) trust, risk perception
and social economic status are positive predictors for mitigation intentions, whereas psychological vulnerability is a negative
predictor; and (3) psychological variables are stronger predictors for mitigation intentions than that of socio-economic variables.
In light of these findings, the policy implications and intervention strategy are also discussed.
相似文献
| Shuyeu LinEmail: |
11.
A deep geologic repository (DGR) situated on the Canadian Shield will be subject to long-term climate change that will markedly
alter surface conditions as a result of glaciation and permafrost penetration. Systematic, two-dimensional and three-dimensional
coupled thermal–hydraulic–mechanical finite-element simulations with varying degrees of coupling, including depth-dependent
salinity (represented as a change in groundwater density) and temperature-dependent density and viscosity, were undertaken
to address the implications of glaciation on groundwater flow system dynamics as it could affect DGR performance. The modelling
domain consisted of a 1.6-km deep sub-regional scale (≈100 km2) fractured Shield flow system. Initial and transient thermal, hydraulic and mechanical boundary conditions were developed
from two realizations of the University of Toronto Glacial Systems Model of the last Laurentide glaciation. Results indicate
that during the glacial loading/unloading cycle, for this particular conceptual model, there is limited penetration of glacial
meltwaters to depth and small residual anomalous hydraulic head. During glacial coverage, the mechanical factor of safety
increases in the moderately fractured and sparsely fractured rock mass, but principal effective stress reorientation also
occurs. Given the assumed nonglacial in situ state of stress and mechanical properties, the fracture zones were predicted
to be less stable under glacial conditions.
相似文献
| Tin ChanEmail: |
12.
P. Mogilevsky 《Physics and Chemistry of Minerals》2007,34(3):201-214
The regular solid solution model has been applied to solid solubility in the monazite–xenotime systems and is verified against
the available experimental data for LaPO4–YPO4 and CePO4–YPO4 systems. The model is then used to predict the miscibility gaps in a number of other monazite–xenotime systems. The implications
for prospective two-phase monazite–xenotime fiber coatings for applications in ceramic matrix composites (CMCs) are discussed.
相似文献
| P. MogilevskyEmail: |
13.
Summary The question of alternative technologies for high-speed Internet access lies at the heart of rural development problems. In
this paper, we focus on one of those technologies, the system combining satellite technologies and Wi-Fi. Based on an empirical
study carried out in three rural areas, we analyze the dynamics of the use and appropriation of that technology by the companies
and organizations participating in the experiment. Considered both from a technical and social standpoint, the technology
‘in use’ appears here in its structuring dimensions.
相似文献
| Valérie FautreroEmail: |
14.
This study seeks to gauge how far China’s container-related dynamics between 1990 and 2005 fit into the wider perspective
about transport and development within developing countries. In particular, attention is focussed on the role of specific
modes to determine the extent of the penetration of containers within China. Before addressing these key issues extant models
relating to an understanding of port and transport evolution in less-developed countries are recalled, synthesized and used
as a base upon which an appropriate review of China’s case can be conducted. Applying them to China’s northern, central and
southern port ranges not only helps assess the efficacy of these models but also highlights the contribution of individual
modes.
相似文献
| Claude ComtoisEmail: |
15.
Melt inclusion formation mechanisms and compositional effects in high-An feldspar and high-Fo olivine in anhydrous mafic silicate liquids 总被引：1，自引：1，他引：0
Important aspects of melt inclusion formation and potential compositions effects have been addressed through a series of experiments using anorthite/fosterite saturated anhydrous mafic liquids. Experimental charges were cooled from 1,300 to 1,230 and 1,210°C at rates of 1–10°/min followed by 0–24 h isothermal periods. Hopper and skeletal crystal morphologies with variable degrees of completeness developed during the cooling period. Planar overgrowth of these textures during isothermal periods led to the formation of inclusions, the majority of which formed after 6 h of isothermal run time. We suggest that the change in morphologies is related to a decrease in growth rates and changes in dominant growth mechanisms. In general, inclusion compositions were uniform and similar to the host glass, indicating that with the isothermal times required for most inclusions to form, a boundary layer was not entrapped that could be detected within the limits of our analyses.
相似文献
| Edward KohutEmail: Phone: +1-541-7373023Fax: +1-541-7371200 |
| Roger L. NielsenEmail: Phone: +1-541-7371235 |
16.
17.
Dmitry L. Lakshtanov Stanislav V. Sinogeikin Jay D. Bass 《Physics and Chemistry of Minerals》2007,34(1):11-22
The single-crystal acoustic velocities of α- and β-quartz were measured by Brillouin spectroscopy to a maximum temperature
>1,500°C at room pressure. From these velocities, the single-crystal elastic moduli were calculated up to 1,050°C, exceeding
the temperature range of previous measurements by 350°C for the elastic moduli and by 710°C for acoustic velocities. The ordinary
refractive index (n
o) of α- and β-quartz was measured from room temperature to 800°C. In the temperature interval from ∼950 to 1,000°C a subtle
change in the temperature derivative of the longitudinal acoustic velocity was observed in platelet geometry for all measured
directions. The high-temperature acoustic velocity data may indicate the presence of a second phase, presumably β-cristobalite,
that nucleates below 1,000°C.
相似文献
| Dmitry L. LakshtanovEmail: |
18.
Spatial and temporal knowledge representation 总被引：1，自引：1，他引：0
Antony Galton 《Earth Science Informatics》2009,2(3):169-187
Knowledge Representation (KR) originated as a discipline within Artificial Intelligence, and is concerned with the representation
of knowledge in symbolic form so that it can be stored and manipulated on a computer. This article surveys that part of KR
that is concerned with the representation of space and time, with particular reference to the use of such representations
in geographical information science.
相似文献
| Antony GaltonEmail: |
19.
Seagrass populations have been declining globally, with changes attributed to anthropogenic stresses and, more recently, negative effects of global climate change. We examined the distribution of Zostera marina (eelgrass) dominated beds in the York River, Chesapeake Bay, VA over an 8-year time period. Using a temperature-dependent light model, declines in upriver areas were associated with higher light attenuation, resulting in lower light availability relative to compensating light requirements of Z. marina compared with downriver areas. An inverse relationship was observed between SAV growth and temperature with a change between net bed cover increases and decreases for the period of 2004–2011 observed at approximately 23 °C. Z. marina-dominated beds in the lower river have been recovering from a die-off event in 2005 and experienced another near complete decline in 2010, losing an average of 97 % of coverage of Z. marina from June to October. These 2010 declines were attributed to an early summer heat event in which daily mean water temperatures increased from 25 to 30 °C over a 2-week time period, considerably higher than previous years when complete die-offs were not observed. Z. marina recovery from this event was minimal, while Ruppia maritima (widgeongrass) expanded its abundance. Water temperatures are projected to continue to increase in the Chesapeake Bay and elsewhere. These results suggest that short-term exposures to rapidly increasing temperatures by 4–5 °C above normal during summer months can result in widespread diebacks that may lead to Z. marina extirpation from historically vegetated areas, with the potential replacement by other species. 相似文献
20.
Geographers show keen interest in projected images employed in tourism as these images both reflect the ideas of the image
producers and influence tourists’ perceptions and (spatial) behaviour. This article focuses on intentional and unintentional
projected images of the Netherlands. The former is especially selective: it relies on stereotypes and presents Holland. The
unintentional projected image created in four travel guides is less stereotyped. While the focus is still on Holland, other
areas of the country are presented as well. Both intentional and unintentional projected images rely on ’othering’ and ’alterity’
to make the Netherlands a unique destination and to offer the tourists a trip that is far from everyday life. However travel
guides use ’alterity’ in different ways and at different levels of scale to create a regional geography of the Netherlands
as well.
相似文献
| Bouke van GorpEmail: |