scholarly journals Fluvial processes and landforms

2022 ◽  
pp. M58-2021-18
Author(s):  
R. I. Ferguson ◽  
J. Lewin ◽  
R. J. Hardy
Keyword(s):  
Conceptual Models ◽  
Volcanic Eruptions ◽  
Field Studies ◽  
Anthropogenic Change ◽  
Site Specific ◽  
Bedrock Rivers ◽  
Fluvial Processes ◽  
Theoretical Approaches ◽  
Major Floods ◽  
Sustained Increase

AbstractThe period 1965-2000 saw a sustained increase in research and publication on fluvial processes and landforms. The trend toward generalisation and/or mechanistic understanding, rather than site-specific history, continued. Research was multi-disciplinary, with important contributions from hydraulic engineers, geologists and physical geographers and from experimental and theoretical approaches as well as geomorphological and sedimentological fieldwork. Rapidly increasing computer power underpinned new measurement methods and greatly increased the scope of data analysis and numerical modelling. There were major advances in understanding the interaction of river process and form at reach scale, with growing recognition of differences between sand-bed and coarse-bed rivers. Field studies outside Europe and North America led to greater awareness of the diversity of river planforms and deposition landforms. Conceptual models of how rivers respond to natural or anthropogenic change in boundary conditions at different timescales were refined, taking advantage of studies of response to land use change, major floods, and volcanic eruptions. Dating of sediments allowed greater appreciation of fluctuations in the incidence of extreme driving events over centuries and thousands of years. Towards the end of the period research on bedrock rivers began to take off.

scholarly journals Aeolian Remobilisation of Volcanic Ash: Outcomes of a Workshop in the Argentinian Patagonia

2020 ◽  
Vol 8 ◽  
Author(s):  
Paul A. Jarvis ◽  
Costanza Bonadonna ◽  
Lucia Dominguez ◽  
Pablo Forte ◽  
Corine Frischknecht ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Friction Velocity ◽  
Critical Infrastructure ◽  
Dust Emission ◽  
Source Area ◽  
Field Measurements ◽  
Volcanic Eruptions ◽  
Field Studies ◽  
Sediment Traps ◽  
Economic Sectors

During explosive volcanic eruptions, large quantities of tephra can be dispersed and deposited over wide areas. Following deposition, subsequent aeolian remobilisation of ash can potentially exacerbate primary impacts on timescales of months to millennia. Recent ash remobilisation events (e.g., following eruptions of Cordón Caulle 2011; Chile, and Eyjafjallajökull 2010, Iceland) have highlighted this to be a recurring phenomenon with consequences for human health, economic sectors, and critical infrastructure. Consequently, scientists from observatories and Volcanic Ash Advisory Centers (VAACs), as well as researchers from fields including volcanology, aeolian processes and soil sciences, convened at the San Carlos de Bariloche headquarters of the Argentinian National Institute of Agricultural Technology to discuss the “state of the art” for field studies of remobilised deposits as well as monitoring, modeling and understanding ash remobilisation. In this article, we identify practices for field characterisation of deposits and active processes, including mapping, particle characterisation and sediment traps. Furthermore, since forecast models currently rely on poorly-constrained dust emission schemes, we call for laboratory and field measurements to better parameterise the flux of volcanic ash as a function of friction velocity. While source area location and extent are currently the primary inputs for dispersion models, once emission schemes become more sophisticated and better constrained, other parameters will also become important (e.g., source material volume and properties, effective precipitation, type and distribution of vegetation cover, friction velocity). Thus, aeolian ash remobilisation hazard and associated impact assessment require systematic monitoring, including the development of a regularly-updated spatial database of resuspension source areas.

Cognition et communication: Un paradigme de recherche et d’application

2011 ◽  
Vol 50 (3-4) ◽  
pp. 656-677 ◽  
Author(s):  
Valery Nosulenko ◽  
Elena Samoylenko
Keyword(s):  
Social Psychology ◽  
Field Studies ◽  
Interdisciplinary Studies ◽  
Human Cognition ◽  
Research Projects ◽  
Theoretical Approaches ◽  
Communication Processes ◽  
Starting Point ◽  
Quality Approach ◽  
Russian Research

The paradigm ‘Cognition and Communication’ has served as a methodological basis for interdisciplinary studies carried out within the framework of Franco-Russian research projects in the field of psychology. The importance of investigating human cognition and activity in relationship with communication processes has been taken as a starting-point for these studies. This 25-year collaboration has made possible the development of new perspectives (e.g. the perceived quality approach) and research methods (e.g. techniques of free verbalization analysis) as well as their application in field studies. This collaboration has also resulted in a fruitful exchange of theoretical approaches among French and Russian researchers. The studies carried out in the field of cognition and communication have involved a number of disciplines: general, experimental and social psychology, ergonomics and education. This article presents a synthesis of a number of results obtained within the framework of Franco-Russian projects as well as various perspectives for future collaboration.

Impact of volcanic halogens on the ozone layer and climate, a look to the past to highlight the present

2020 ◽  
Author(s):  
Hélène Balcone-Boissard ◽  
Thiébaut D'Augustin ◽  
Georges Boudon ◽  
Slimane Bekki ◽  
Magali Bonifacie ◽  
...  
Keyword(s):  
Volcanic Eruptions ◽  
Field Work ◽  
Field Studies ◽  
Global Scale ◽  
Ozone Layer ◽  
Volatile Species ◽  
Magma Supply ◽  
Global Impacts ◽  
Almost All ◽  
The Impact

<p>Explosive eruptions of the Plinian type inject large amounts of particles (pumice, ash, aerosols) and volatile species into the atmosphere. They result from the rapid discharge of a magma chamber and involve large volumes of magma (from a km<sup>3</sup> to hundreds of km<sup>3</sup>). Such eruptions correspond to a rapid ascent of magma in the conduit driven by the exsolution of volatile species. If the magma supply is continuous, this jet produces a convective eruptive column that can reach tens of km in height and transports gas and particles (pumice, ash, aerosols) directly into the stratosphere. Depending on the latitude of the volcano, the volume of implied magma, the height of the eruptive plume and the composition of the released gaseous and particulate mixture, these events can strongly affect the environment at the local or even at a global scale. Almost all studies on global impacts of volcanic eruptions have largely focused on the sulfur component. Volcanoes are also responsible for the emission of halogens which have a crucial impact on the ozone layer and therefore the climate.</p><p>The objective of our project is to revisit the issue of the impact of volcanism on the atmosphere and climate by considering not only the sulfur component but also the halogen component. We will provide field work-based constraints on the strength of halogen (Cl and Br) emissions and on degassing processes for key eruptions, we will characterise the dynamics of volcanic plumes, notably the vertical distribution of emissions and we will explore and quantify the respective impacts of sulfur and halogen emissions on the ozone layer and climate.</p><p> </p><p>Here we will shed light on the methodology that will combine field campaign, laboratory analysis of collected samples and a hierarchy of modelling tools to study. We use an approach combining field studies, petrological characterization, geochemical measurements including isotopic data, estimation of the volume of involved magma and the height of injection of gases and particles by modelling the eruptive plume dynamic and numerical simulation of the impacts at the plume scale and at the global scale.  The first halogen budget will also be presented.</p>

Site-specific force-vector field studies of KBr(001) by atomic force microscopy

2009 ◽  
Vol 20 (26) ◽  
pp. 264013 ◽  
Author(s):  
Kai Ruschmeier ◽  
André Schirmeisen ◽  
Regina Hoffmann
Keyword(s):  
Atomic Force Microscopy ◽  
Vector Field ◽  
Field Studies ◽  
Specific Force ◽  
Force Vector ◽  
Site Specific ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals “Volcanism in the Chugoku region: a review for the first UNESCO field school on Geoenvironmental disaster reduction”

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Andreas Auer
Keyword(s):  
Natural Hazards ◽  
Volcanic Eruptions ◽  
Field Studies ◽  
Volcanic Field ◽  
Disaster Mitigation ◽  
Practical Skills ◽  
Geological Samples ◽  
Southwest Japan ◽  
Field School ◽  
Mitigation Effort

AbstractField studies related to natural hazards are an integral part of any disaster mitigation effort, because geological samples and field records must initially be obtained from the context in which they occur. A sound fieldwork and careful observation and documentation of field relations is crucial for meaningful subsequent laboratory work, further data analysis and modelling. Teaching the necessary practical skills that enable students to recognize natural disaster events in the geological records and to understand circumstances under which they occur is not a trivial task. Some barriers to fieldwork usually exist, especially when the teaching subject focusses on natural disasters. Beside cost and logistics it is often the lack of suitable sites, that serve as instructive examples, displaying the deposits, structures and preserved evidence of natural hazards in the geological record. To students of volcanology, southwest Japan offers an almost unparalleled variety of interesting volcanic successions, including a broad range of different volcanic landforms and deposits that illustrate the various hazards associated with volcanic eruptions. This review will provide a brief overview of the geology of southwest Japan with special emphasis on the igneous and volcanic evolution. It will give participants of the field school a minimum of required background and anybody beyond a quick introduction into one of the most diverse and interesting volcanic field areas in the world.

Theoretical Approaches to Studying Incivility in Nursing Education

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Tatiana Penconek
Keyword(s):  
Nursing Education ◽  
Attribution Theory ◽  
Conceptual Models ◽  
Critical Social Theory ◽  
Knowledge Development ◽  
Comprehensive Understanding ◽  
Group Behaviour ◽  
Theoretical Approaches ◽  
Educational Environments ◽  
Theoretical Considerations

AbstractIncivility is a concerning occurrence in nursing education. Examining the concept of incivility is critical to the development of strategies used to prevent and mitigate experiences in nursing education. The purpose of this paper is to examine this concept through theoretical lenses of oppressed group behaviour, attribution theory, and conceptual models of empowerment. A critical social theory perspective is outlined as an additional theoretical approach to studying incivility in nursing education. Examination through various theoretical lenses may help to describe, explain, and predict incivility in nursing education. Theoretical considerations of this concept are limited but may hold the key to comprehensive understanding and advancement of knowledge. The ultimate goal of theoretical and knowledge development of incivility in nursing education is the creation and maintenance of civil educational environments.

scholarly journals Assessment of time of emergence of anthropogenic deoxygenation and warming: insights from a CESM simulation from 850 to 2100 CE

2019 ◽  
Author(s):  
Angélique Hameau ◽  
Juliette Mignot ◽  
Fortunat Joos
Keyword(s):  
Volcanic Eruptions ◽  
Internal Variability ◽  
Marine Ecosystems ◽  
Natural Variability ◽  
Last Millennium ◽  
Anthropogenic Change ◽  
Methodological Choices ◽  
Deep Waters ◽  
Short Period ◽  
Community Earth System Model

Abstract. Marine deoxygenation and anthropogenic ocean warming are observed and projected to aggravate under continued greenhouse gas emissions. These changes potentially adversely affect the functioning and services of marine ecosystems. A key question is whether marine ecosystems are already or will soon be exposed to environmental conditions not experienced during the last millennium. We find that anthropogenic deoxygenation and warming in the thermocline have today already left the bounds of natural variability in respectively 60 % and 90 % of total ocean area in a forced simulation with the Community Earth System Model (CESM) over the period 850 to 2100. Natural variability is assessed from last millennium (850–1800) results considering forcing from explosive volcanic eruptions, solar irradiance, and greenhouse gases in addition to internal, chaotic variability. Control simulations are typically used to estimate variability. However, natural variability in oxygen (O2) and temperature (T) are systematically larger than internal variability (e.g. the latter amounts to 20 % for T and 60 % for O2 in the thermocline), rendering such estimates of natural variability to be biased low. Results suggest that anthropogenic change in apparent oxygen utilisation (AOU) and in O2 solubility (O2,sol) are earlier detectable by measurements than in O2 in the tropical thermocline, where biological and solubility-driven O2 changes counteract each other. Both natural variability and change in AOU are predominantly driven by variations in circulation with a smaller role for productivity. Ventilation becomes more vigorous in the tropical thermocline by the end of the 21st century, whereas ideal age in deep waters increases by more than 200 years until 2100. Different methodological choices are compared and the time for an anthropogenic signal to emergence (ToE) is earlier in many thermocline regions when using variability from a short period, the control, or estimates from the industrial period instead variability from the last millennium. Our results highlight that published methods lead to deviations in ToE estimates, calling for a careful quantification of variability and that realised anthropogenic change exceeds natural variations in many regions.

scholarly journals Local stresses, dyke arrest and surface deformation in volcanic edificesand rift zones

2009 ◽  
Vol 47 (4) ◽  
Author(s):  
A. Gudmundsson ◽  
L. S. Brenner
Keyword(s):  
Surface Deformation ◽  
Numerical Models ◽  
Local Stress ◽  
Volcanic Eruptions ◽  
Field Studies ◽  
Normal Faults ◽  
Small Surface ◽  
Tensile Stresses ◽  
Surface Stresses ◽  
Rift Zones

Field studies indicate that nearly all eruptions in volcanic edifices and rift zones are supplied with magma through fractures (dykes) that are opened by magmatic overpressure. While (inferred) dyke injections are frequent during unrest periods, volcanic eruptions are, in comparison, infrequent, suggesting that most dykes become arrested at certain depths in the crust, in agreement with field studies. The frequency of dyke arrest can be partly explained by the numerical models presented here which indicate that volcanic edifices and rift zones consisting of rocks of contrasting mechanical properties, such as soft pyroclastic layers and stiff lava flows, commonly develop local stress fields that encourage dyke arrest. During unrest, surface deformation studies are routinely used to infer the geometries of arrested dykes, and some models (using homogeneous, isotropic half-spaces) infer large grabens to be induced by such dykes. Our results, however, show that the dyke-tip tensile stresses are normally much greater than the induced surface stresses, making it difficult to explain how a dyke can induce surface stresses in excess of the tensile (or shear) strength while the same strength is not exceeded at the (arrested) dyke tip. Also, arrested dyke tips in eroded or active rift zones are normally not associated with dyke-induced grabens or normal faults, and some dykes arrested within a few metres of the surface do not generate faults or grabens. The numerical models show that abrupt changes in Young's moduli(stiffnesses), layers with relatively high dyke-normal compressive stresses (stress barriers), and weak horizontal contacts may make the dyke-induced surface tensile stresses too small for significant fault or graben formation to occur in rift zones or volcanic edifices. Also, these small surface stresses may have no simple relation to the dyke geometry or the depth to its tip. Thus, for a layered crust with weak contacts, straightforward inversion of surface geodetic data may lead to unreliable geometries of arrested dykes in active rift zones and volcanic edifices.

Framing the visitor experience in sacred places

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mujde Bideci ◽  
Caglar Bideci
Keyword(s):  
Quantitative Research ◽  
Field Studies ◽  
Virgin Mary ◽  
Dimensional Structure ◽  
Visitor Experience ◽  
Sacred Places ◽  
Sacred Place ◽  
Content Type ◽  
Theoretical Approaches ◽  
Visitor Experiences

PurposeThe purpose of this study is to explore the dimensional structure of visitor experience in a sacred place based on the framing process.Design/methodology/approachMix-method research was conducted in Turkey–Virgin Mary House which featured a sacred and popular tourist destination. Qualitative research, including interviews and expert panels, was used to create a set of knowledge for further analysis. Quantitative research, including two field studies comprising 842 participants, was used to validate the framing of visitor experiences in a sacred place providing reliability and construct validity.FindingsThe six dimensions were found within three framing axes of religious, environmental and organizational: inner experience; religious experience; physical environment; history; tour organization and service experience.Originality/valueCurrent studies on visitor experience in a sacred place have mainly focused on emotions, motivations or physical dimensions. By synthesising the framing process and theoretical approaches, this study contributes to the literature by analysing the unique characteristics of visitors' experiences in sacred places, regardless of their religious identities.

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