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Conceptual Advances (conceptual + advance)

Distribution by Scientific Domains

Earth and Environmental Science	40%

Selected Abstracts

The uptake of applied ecology

JOURNAL OF APPLIED ECOLOGY, Issue 1 2002
S. J. Ormerod
Summary 1We asked 229 authors who have published recently in the Journal of Applied Ecology (1999,2001) whether their papers made management or policy recommendations and whether they had evidence of consequent uptake. 2A total of 108 respondents working in the UK (34%), Europe (30%), the Americas (12%), Australasia (11%), Asia (7%) and Africa (6%) reported on 110 papers. They represented agro-ecosystems (35%), temperate forests or woodlands (16%), savanna, grass or arid lands (11%), rivers or wetlands (10%), estuaries or marine systems (7%) and tropical forests (5%). The major organisms were invertebrates (27%), birds (24%), mammals (21%) and higher plants (21%). Topics apparently under-represented in recent coverage include ecosystem science, urban areas, soils, mountain systems, fish, amphibians and lower organisms such as algae. 3Almost all papers (99%) carried recommendations and for 57% there was evidence of uptake in the broad categories of ,environmental management or models', ,information, training and education' and ,monitoring and assessment'. Most uptake involved large geographical scales through habitat or species management plans (32% of cases), effects on reserve design or designation (6%), and effects on agri-environmental policy (5%). The development of further research (11%), the communication of methods to other ecologists (9%), the dissemination of recommendations to practitioners or agencies (7%), and uptake in training or education (5%) were important uses of information. 4Prestige from publication in the Journal of Applied Ecology aided several authors in convincing end-users of research value. User involvement in research as participants or funders was widespread (> 42% of papers), a fact which almost certainly promotes uptake along with the parallel dissemination of management messages. We view applied issues as an important interface between end-users and ecologists of value to ,both' communities but suggest that improved communication will further benefit the sponsorship and application of ecological science. 5The major reason offered for lack of uptake was that it was still too soon after publication (21% of respondents). Costs, difficulty of implementation, the scale of the problem, and ,challenges to existing thinking' each figured in more than one response. 6For some respondents, papers were led by curiosity rather than the need for direct application. Several authors published in the Journal to share ideas internationally, or said that recommendations were general, conceptual or long-term rather than specific. The editors of the Journal of Applied Ecology recognize the seminal importance of contributions that affect policy incrementally and conceptually as much as those with specific application. 7These data provide evidence that ecological science is aiding environmental management and policy across a wide range of regions, ecosystems and types of organisms; rather than merely detecting problems, applied ecology is offering solutions both directly and more diffusely through conceptual advance. We invite the user community to offer their own perspectives about the value of research-led publications such as this Journal, about how links between researchers and users might be strengthened, and about how the uptake of applied ecology might be further advanced. [source]

Long-term landscape evolution: linking tectonics and surface processes

EARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2007
Paul Bishop
Abstract Research in landscape evolution over millions to tens of millions of years slowed considerably in the mid-20th century, when Davisian and other approaches to geomorphology were replaced by functional, morphometric and ultimately process-based approaches. Hack's scheme of dynamic equilibrium in landscape evolution was perhaps the major theoretical contribution to long-term landscape evolution between the 1950s and about 1990, but it essentially ,looked back' to Davis for its springboard to a viewpoint contrary to that of Davis, as did less widely known schemes, such as Crickmay's hypothesis of unequal activity. Since about 1990, the field of long-term landscape evolution has blossomed again, stimulated by the plate tectonics revolution and its re-forging of the link between tectonics and topography, and by the development of numerical models that explore the links between tectonic processes and surface processes. This numerical modelling of landscape evolution has been built around formulation of bedrock river processes and slope processes, and has mostly focused on high-elevation passive continental margins and convergent zones; these models now routinely include flexural and denudational isostasy. Major breakthroughs in analytical and geochronological techniques have been of profound relevance to all of the above. Low-temperature thermochronology, and in particular apatite fission track analysis and (U,Th)/He analysis in apatite, have enabled rates of rock uplift and denudational exhumation from relatively shallow crustal depths (up to about 4 km) to be determined directly from, in effect, rock hand specimens. In a few situations, (U,Th)/He analysis has been used to determine the antiquity of major, long-wavelength topography. Cosmogenic isotope analysis has enabled the determination of the ,ages' of bedrock and sedimentary surfaces, and/or the rates of denudation of these surfaces. These latter advances represent in some ways a ,holy grail' in geomorphology in that they enable determination of ,dates and rates' of geomorphological processes directly from rock surfaces. The increasing availability of analytical techniques such as cosmogenic isotope analysis should mean that much larger data sets become possible and lead to more sophisticated analyses, such as probability density functions (PDFs) of cosmogenic ages and even of cosmogenic isotope concentrations (CICs). PDFs of isotope concentrations must be a function of catchment area geomorphology (including tectonics) and it is at least theoretically possible to infer aspects of source area geomorphology and geomorphological processes from PDFs of CICs in sediments (,detrital CICs'). Thus it may be possible to use PDFs of detrital CICs in basin sediments as a tool to infer aspects of the sediments' source area geomorphology and tectonics, complementing the standard sedimentological textural and compositional approaches to such issues. One of the most stimulating of recent conceptual advances has followed the considerations of the relationships between tectonics, climate and surface processes and especially the recognition of the importance of denudational isostasy in driving rock uplift (i.e. in driving tectonics and crustal processes). Attention has been focused very directly on surface processes and on the ways in which they may ,drive' rock uplift and thus even influence sub-surface crustal conditions, such as pressure and temperature. Consequently, the broader geoscience communities are looking to geomorphologists to provide more detailed information on rates and processes of bedrock channel incision, as well as on catchment responses to such bedrock channel processes. More sophisticated numerical models of processes in bedrock channels and on their flanking hillslopes are required. In current numerical models of long-term evolution of hillslopes and interfluves, for example, the simple dependency on slope of both the fluvial and hillslope components of these models means that a Davisian-type of landscape evolution characterized by slope lowering is inevitably ,confirmed' by the models. In numerical modelling, the next advances will require better parameterized algorithms for hillslope processes, and more sophisticated formulations of bedrock channel incision processes, incorporating, for example, the effects of sediment shielding of the bed. Such increasing sophistication must be matched by careful assessment and testing of model outputs using pre-established criteria and tests. Confirmation by these more sophisticated Davisian-type numerical models of slope lowering under conditions of tectonic stability (no active rock uplift), and of constant slope angle and steady-state landscape under conditions of ongoing rock uplift, will indicate that the Davis and Hack models are not mutually exclusive. A Hack-type model (or a variant of it, incorporating slope adjustment to rock strength rather than to regolith strength) will apply to active settings where there is sufficient stream power and/or sediment flux for channels to incise at the rate of rock uplift. Post-orogenic settings of decreased (or zero) active rock uplift would be characterized by a Davisian scheme of declining slope angles and non-steady-state (or transient) landscapes. Such post-orogenic landscapes deserve much more attention than they have received of late, not least because the intriguing questions they pose about the preservation of ancient landscapes were hinted at in passing in the 1960s and have recently re-surfaced. As we begin to ask again some of the grand questions that lay at the heart of geomorphology in its earliest days, large-scale geomorphology is on the threshold of another ,golden' era to match that of the first half of the 20th century, when cyclical approaches underpinned virtually all geomorphological work. Copyright © 2007 John Wiley & Sons, Ltd. [source]

The evolving classification of soft tissue tumours: an update based on the new WHO classification

HISTOPATHOLOGY, Issue 1 2006
C D M Fletcher
Tumour classifications have become an integral part of modern oncology and, for pathologists, they provide guidelines which facilitate diagnostic and prognostic reproducibility. In many organ systems and most especially over the past decade or so, the World Health Organization (WHO) classifications have become pre-eminent, partly enabled by the timely publication of new ,blue books' which now incorporate detailed text and copious illustrations. The new WHO classification of soft tissue tumours was introduced in late 2002 and, because it represents a broad consensus view, it has gained widespread acceptance. This review summarizes the changes, both major and minor, which were introduced and briefly describes the significant number of tumour types which have been first recognized or properly characterized during the past decade. Arguably the four most significant conceptual advances have been: (i) the formal recognition that morphologically benign lesions (such as cutaneous fibrous histiocytoma) may very rarely metastasize; (ii) the general acceptance that most pleomorphic sarcomas can be meaningfully subclassified and that so-called malignant fibrous histiocytoma is not a definable entity, but instead represents a wastebasket of undifferentiated pleomorphic sarcomas, accounting for no more than 5% of adult soft tissue sarcomas; (iii) the acknowledgement that most lesions formerly known as haemangiopericytoma show no evidence of pericytic differentiation and, instead, are fibroblastic in nature and form a morphological continuum with solitary fibrous tumour; and (iv) the increasing appreciation that not only do we not know from which cell type(s) most soft tissue tumours originate (histogenesis) but, for many, we do not recognize their line of differentiation or lineage,hence an increasing number of tumours ar placed in the ,uncertain differentiation' category. [source]

Two decades of urban climate research: a review of turbulence, exchanges of energy and water, and the urban heat island

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2003
A. John Arnfield
Abstract Progress in urban climatology over the two decades since the first publication of the International Journal of Climatology is reviewed. It is emphasized that urban climatology during this period has benefited from conceptual advances made in microclimatology and boundary-layer climatology in general. The role of scale, heterogeneity, dynamic source areas for turbulent fluxes and the complexity introduced by the roughness sublayer over the tall, rigid roughness elements of cities is described. The diversity of urban heat islands, depending on the medium sensed and the sensing technique, is explained. The review focuses on two areas within urban climatology. First, it assesses advances in the study of selected urban climatic processes relating to urban atmospheric turbulence (including surface roughness) and exchange processes for energy and water, at scales of consideration ranging from individual facets of the urban environment, through streets and city blocks to neighbourhoods. Second, it explores the literature on the urban temperature field. The state of knowledge about urban heat islands around 1980 is described and work since then is assessed in terms of similarities to and contrasts with that situation. Finally, the main advances are summarized and recommendations for urban climate work in the future are made. Copyright © 2003 Royal Meteorological Society. [source]

Conundrums in mixed woody,herbaceous plant systems

JOURNAL OF BIOGEOGRAPHY, Issue 11 2003
Joanna I. House
Abstract Aims To identify approaches to improve our understanding of, and predictive capability for, mixed tree,grass systems. Elucidation of the interactions, dynamics and determinants, and identification of robust generalizations that can be broadly applied to tree,grass systems would benefit ecological theory, modelling and land management. Methods A series of workshops brought together scientific expertise to review theory, data availability, modelling approaches and key questions. Location Ecosystems characterized by mixtures of herbaceous and woody plant life-forms, often termed ,savannas', range from open grasslands with few woody plants, to woodlands or forests with a grass layer. These ecosystems represent a substantial portion of the terrestrial biosphere, an important wildlife habitat, and a major resource for provision of livestock, fuel wood and other products. Results Although many concepts and principles developed for grassland and forest systems are relevant to these dual life-form communities, the novel, complex, nonlinear behaviour of mixed tree,grass systems cannot be accounted for by simply studying or modelling woody and herbaceous components independently. A more robust understanding requires addressing three fundamental conundrums: (1) The ,treeness' conundrum. What controls the relative abundance of woody and herbaceous plants for a given set of conditions at given site? (2) The coexistence conundrum. How do the life-forms interact with each other? Is a given woody,herbaceous ratio dynamically stable and persistent under a particular set of conditions? (3) The net primary productivity (NPP) conundrum. How does NPP of the woody vegetation, the herbaceous vegetation, and the total ecosystem (woody + herbaceous) change with changes in the tree,grass ratio? Tests of the theory and conceptual models of determinants of mixed woody,herbaceous systems have been largely site- or region-specific and have seldom been broadly or quantitatively evaluated. Cross-site syntheses based on data and modelling are required to address the conundrums and identify emerging patterns, yet, there are very few data sets for which either biomass or NPP have been quantified for both the woody and the herbaceous components of tree,grass systems. Furthermore, there are few cross-site comparisons spanning the diverse array of woody,herbaceous mixtures. Hence, initial synthesis studies should focus on compiling and standardizing a global data base which could be (1) explored to ascertain if robust generalizations and consistent patterns exist; and (2) used to evaluate the performance of savanna simulation models over a range of woody,herbaceous mixtures. Savanna structure and productivity are the result of complex and dynamic interactions between climate, soils and disturbances, notably fire and herbivory. Such factors are difficult to isolate or experimentally manipulate in order to evaluate their impacts at spatial and temporal scales appropriate for assessing ecosystem dynamics. These factors can, however, be evaluated with simulation models. Existing savanna models vary markedly with respect to their conceptual approach, their data requirements and the extent to which they incorporate mechanistic processes. Model intercomparisons can elucidate those approaches most suitable for various research questions and management applications. Conclusion Theoretical and conceptual advances could be achieved by considering a broad continuum of grass,shrub,tree combinations using data meta-analysis techniques and modelling. [source]