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Search Results: 1 - 10 of 401467 matches for " Geerten M. Hengeveld "
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Sustainability Impact Assessment of Forest Management Alternatives in Europe: an Introductory Background and Framework
Jean-Michel Carnus,Geerten M. Hengeveld,Bill Mason
Ecology and Society , 2012, DOI: 10.5751/es-04838-170449
Abstract: Adaptation of forest management practices in the context of rapid climatic and socioeconomic changes is a global concern. Stakeholders in the forest-based sector as well as policy makers need improved methods and tools to assess potential impacts of changes in management on sustainability indicators. In this special feature, we introduce a methodological framework for classification of forest management approaches in European forestry and explore how changes in forest management might affect the delivery of various ecosystem goods and services and appropriate sustainability indicators over time and space from local to continental scales. The complementary papers in this special feature explore different aspects of sustainability and risks in representative European forest systems as affected by forest management. We show how a common framework plus supporting growth models and indicators can be used to examine the effects of management on ecosystem services and so provide a first step toward the development of a more integrated approach for strategic forest planning and sustainable use of forest ecosystems.
Classification of Forest Management Approaches: A New Conceptual Framework and Its Applicability to European Forestry
Philipp S. Duncker,Susana M. Barreiro,Geerten M. Hengeveld,Torgny Lind
Ecology and Society , 2012, DOI: 10.5751/es-05262-170451
Abstract: The choice between different forest management practices is a crucial step in short, medium, and long-term decision making in forestry and when setting up measures to support a regional or national forest policy. Some conditions such as biogeographically determined site factors, exposure to major disturbances, and societal demands are predetermined, whereas operational processes such as species selection, site preparation, planting, tending, or thinning can be altered by management. In principle, the concept of a forest management approach provides a framework for decision making, including a range of silvicultural operations that influence the development of a stand or group of trees over time. These operations vary among silvicultural systems and can be formulated as a set of basic principles. Consequently, forest management approaches are essentially defined by coherent sets of forest operation processes at a stand level. Five ideal forest management approaches (FMAs) representing a gradient of management intensity are described using specific sets of basic principles that enable comparison across European forests. Each approach is illustrated by a regional European case study. The observed regional variations resulting from changing species composition, stand density, age structure, stand edges, and site conditions can be interpreted using the FMA framework. Despite being arranged along an intensity gradient, the forest management approaches are not considered to be mutually exclusive, as the range of options allows for greater freedom in selecting potential silvicultural operations. As derived goods and services are clearly affected, the five forest management approaches have implications for sustainability. Thus, management objectives can influence the balance between the economic, ecological, and social dimensions of sustainability. The utility of this framework is further demonstrated through the different contributions to this special issue.
A Forest Management Map of European Forests
Geerten M. Hengeveld,Gert-Jan Nabuurs,Markus Didion,Isabel van den Wyngaert
Ecology and Society , 2012, DOI: 10.5751/es-05149-170453
Abstract: Forest management to a large extent determines the possible services that the forest can provide. Different objectives in forest management determine the rotation length and valuation of different stages in forest succession. We present a method of mapping potential forest management at 1-km resolution to inform policy, land use modeling, and forest resource projections. The presented method calculates the suitability of a location to different forest management alternatives based on biotic, abiotic, socioeconomic, and political factors. A sensitivity analysis of the resulting map to the data sources used was performed. This showed that the results are very sensitive to some data sources. The potential use of the map and the sensitivity to the availability of data sources are discussed. An extension to the method, including regional scaling, is suggested. Data availability is the main restriction on refinement of the proposed methodology.
Persistence of Aquatic Insects across Managed Landscapes: Effects of Landscape Permeability on Re-Colonization and Population Recovery
Nika Galic, Geerten M. Hengeveld, Paul J. Van den Brink, Amelie Schmolke, Pernille Thorbek, Eric Bruns, Hans M. Baveco
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054584
Abstract: Human practices in managed landscapes may often adversely affect aquatic biota, such as aquatic insects. Dispersal is often the limiting factor for successful re-colonization and recovery of stressed habitats. Therefore, in this study, we evaluated the effects of landscape permeability, assuming a combination of riparian vegetation (edge permeability) and other vegetation (landscape matrix permeability), and distance between waterbodies on the colonization and recovery potential of weakly flying insects. For this purpose, we developed two models, a movement and a population model of the non-biting midge, Chironomus riparius, an aquatic insect with weak flying abilities. With the movement model we predicted the outcome of dispersal in a landscape with several linear water bodies (ditches) under different assumptions regarding landscape-dependent movement. Output from the movement model constituted the probabilities of encountering another ditch and of staying in the natal ditch or perishing in the landscape matrix, and was used in the second model. With this individual-based model of midge populations, we assessed the implications for population persistence and for recovery potential after an extreme stress event. We showed that a combination of landscape attributes from the movement model determines the fate of dispersing individuals and, once extrapolated to the population level, has a big impact on the persistence and recovery of populations. Population persistence benefited from low edge permeability as it reduced the dispersal mortality which was the main factor determining population persistence and viability. However, population recovery benefited from higher edge permeability, but this was conditional on the low effective distance that ensured fewer losses in the landscape matrix. We discuss these findings with respect to possible landscape management scenarios.
Framework for Modelling Economic Impacts of Invasive Species, Applied to Pine Wood Nematode in Europe
Tarek Soliman, Monique C. M. Mourits, Wopke van der Werf, Geerten M. Hengeveld, Christelle Robinet, Alfons G. J. M. Oude Lansink
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045505
Abstract: Background Economic impact assessment of invasive species requires integration of information on pest entry, establishment and spread, valuation of assets at risk and market consequences at large spatial scales. Here we develop such a framework and demonstrate its application to the pinewood nematode, Bursaphelenchus xylophilus, which threatens the European forestry industry. The effect of spatial resolution on the assessment result is analysed. Methodology/Principal Findings Direct economic impacts resulting from wood loss are computed using partial budgeting at regional scale, while impacts on social welfare are computed by a partial equilibrium analysis of the round wood market at EU scale. Substantial impacts in terms of infested stock are expected in Portugal, Spain, Southern France, and North West Italy but not elsewhere in EU in the near future. The cumulative value of lost forestry stock over a period of 22 years (2008–2030), assuming no regulatory control measures, is estimated at €22 billion. The greatest yearly loss of stock is expected to occur in the period 2014–2019, with a peak of three billion euros in 2016, but stabilizing afterwards at 300–800 million euros/year. The reduction in social welfare follows the loss of stock with considerable delay because the yearly harvest from the forest is only 1.8%. The reduction in social welfare for the downstream round wood market is estimated at €218 million in 2030, whereby consumers incur a welfare loss of €357 million, while producers experience a €139 million increase, due to higher wood prices. The societal impact is expected to extend to well beyond the time horizon of the analysis, and long after the invasion has stopped. Conclusions/Significance Pinewood nematode has large economic consequences for the conifer forestry industry in the EU. A change in spatial resolution affected the calculated directed losses by 24%, but did not critically affect conclusions.
Traditional Biomolecular Structure Determination by NMR Spectroscopy Allows for Major Errors
Sander B Nabuurs,Chris A. E. M Spronk,Geerten W Vuister ,Gert Vriend
PLOS Computational Biology , 2006, DOI: 10.1371/journal.pcbi.0020009
Abstract: One of the major goals of structural genomics projects is to determine the three-dimensional structure of representative members of as many different fold families as possible. Comparative modeling is expected to fill the remaining gaps by providing structural models of homologs of the experimentally determined proteins. However, for such an approach to be successful it is essential that the quality of the experimentally determined structures is adequate. In an attempt to build a homology model for the protein dynein light chain 2A (DLC2A) we found two potential templates, both experimentally determined nuclear magnetic resonance (NMR) structures originating from structural genomics efforts. Despite their high sequence identity (96%), the folds of the two structures are markedly different. This urged us to perform in-depth analyses of both structure ensembles and the deposited experimental data, the results of which clearly identify one of the two models as largely incorrect. Next, we analyzed the quality of a large set of recent NMR-derived structure ensembles originating from both structural genomics projects and individual structure determination groups. Unfortunately, a visual inspection of structures exhibiting lower quality scores than DLC2A reveals that the seriously flawed DLC2A structure is not an isolated incident. Overall, our results illustrate that the quality of NMR structures cannot be reliably evaluated using only traditional experimental input data and overall quality indicators as a reference and clearly demonstrate the urgent need for a tight integration of more sophisticated structure validation tools in NMR structure determination projects. In contrast to common methodologies where structures are typically evaluated as a whole, such tools should preferentially operate on a per-residue basis.
TMD pain: the effect on health related quality of life and the influence of pain duration
Geerten-Has E Tjakkes, Jan-Jaap Reinders, Elisabeth M Tenvergert, Boudewijn Stegenga
Health and Quality of Life Outcomes , 2010, DOI: 10.1186/1477-7525-8-46
Abstract: Data concerning physical and mental health were retrieved from patients with painful temporomandibular disorders. Assessment tools used were: the Mandibular Function Impairment Questionnaire (MFIQ), the Short-Form-36 (SF-36), the Hospital Anxiety and Depression Schedule (HADS), and the General Health Questionnaire (GHQ). In order to examine the influence of the duration of pain on HRQoL, the total sample was divided into three different subgroups. Subgroup 1 consisted of patients with complaints existing less than one year. Patients with complaints from 1 to 3 years were allocated to the second group. The 3rd subgroup included patients with complaints longer than 3 years.The total sample consisted of 95 patients (90 females and 5 males). On most physical and social functioning items, groups 2 and 3 scored significantly worse than the general population. On the other hand, none of the groups differed from the general population when comparing the mental items. Duration of pain was significantly correlated with SF-36 subscale physical functioning and the mandibular impairment.Patients with TMD pain less than one year score better than compared to the population norm. With a longer duration of pain, mental health scores and role limitations due to emotional problems do not appear to be seriously affected by reduced physical health, while social functioning appears to be considerably affected.Temporomandibular disorders (TMDs) comprise a group of disorders that affect the temporomandibular joint (TMJ), the masticatory muscles, or both. TMDs involve musculoskeletal pain, disturbances in the mandibular movement patterns, and/or impairment in functional movement [1]. Pain is the main characteristic of most TMDs and also the main reason for patients to seek treatment [2]. Many TMDs should be considered chronic pain conditions, since they show lot of similarities [3]. Psychological factors have been implicated in the initiation as well in the perpetuation of several TMDs [4]
A plethora of angiopoietin-2 effects during clinical sepsis
Geerten Amerongen, AB Johan Groeneveld
Critical Care , 2010, DOI: 10.1186/cc9053
Abstract: In the past decade, the angiopoietin (ang)-1/2-Tie2 system has increasingly been suggested to play a major role in the various features of human sepsis and acute lung injury and has thereby been considered as a novel therapeutic target [1-3]. High circulating ang-2 levels promote inflammation and vascular permeability (in the lungs), while ang-1 has a protective effect, and these associations are confirmed by clinical studies [4,5]. The putative role of the ang-2/1 balance is gradually being expanded by studies showing that ang-2 levels may predict acute kidney injury and ICU outcome, even independently of disease severity [4,6].In the current issue of Critical Care, Davis and colleagues [1] provide additional evidence that ang-2 release is associated with impaired vasoreactivity in patients with early sepsis, probably via interference with nitric oxide (NO), which can be considered as a pivotal pathophysiologic alteration in human sepsis. They measured vascular reactivity by the non-invasive reactive hyperemiaperipheral artery tonometry (RH-PAT) technique, reviewed elsewhere [7]. Based on these observations, the authors conclude that ang-2 is a more meaningful biomarker of endothelial function in sepsis than 'currently used surrogate measures', but formal evaluation of predictive values are lacking and the correlations are moderate at best. Also, the authors did not measure ang-1 levels, although the balance between ang-2 and ang-1 may determine the net biological effect. Finally, an intervention targeted at these molecules would be needed to reveal a direct role in microvascular responses in sepsis. Indeed, the angiopoietin-1/2-Tie2 system controls the responsiveness of the endothelium via multiple signal transduction pathways, including activation of Rho-like small GTPases, protein kinase C-zeta and Src [2,5], while the protein C system, a therapeutic target of alleged benefit in human septic shock, may also be involved, as recently suggested [8]. Ang-1 may be as
Alinhamento interpessoal, representacional e morfossintático na Gramática Discursivo-Funcional
Hengeveld, Kees;Mackenzie, J. Lachlan;
DELTA: Documenta??o de Estudos em Lingüística Teórica e Aplicada , 2009, DOI: 10.1590/S0102-44502009000100007
Abstract: within the framework of functional discourse grammar (fdg), alignment concerns the relations between the interpersonal, representational and morphosyntactic levels of grammar. this article proposes a typology of languages based upon what we find to be encoded in their morphosyntactic organization: pragmatic distinctions (as in tagalog), semantic distinctions (as in acheh), or distinctions inherent to the morphosyntax (as in english, basque and kham). by including both subject and object, and both accusative and ergative languages in our treatment of morphosyntactic alignment, we provide a better coverage of typological variation and show the potential of fdg for cross-linguistic analysis.
Opposing Effects of the Angiopoietins on the Thrombin-Induced Permeability of Human Pulmonary Microvascular Endothelial Cells
Melanie van der Heijden, Geerten P. van Nieuw Amerongen, Jan van Bezu, Marinus A. Paul, A. B. Johan Groeneveld, Victor W. M. van Hinsbergh
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023448
Abstract: Background Angiopoietin-2 (Ang-2) is associated with lung injury in ALI/ARDS. As endothelial activation by thrombin plays a role in the permeability of acute lung injury and Ang-2 may modulate the kinetics of thrombin-induced permeability by impairing the organization of vascular endothelial (VE-)cadherin, and affecting small Rho GTPases in human pulmonary microvascular endothelial cells (HPMVECs), we hypothesized that Ang-2 acts as a sensitizer of thrombin-induced hyperpermeability of HPMVECs, opposed by Ang-1. Methodology/Principal Findings Permeability was assessed by measuring macromolecule passage and transendothelial electrical resistance (TEER). Angiopoietins did not affect basal permeability. Nevertheless, they had opposing effects on the thrombin-induced permeability, in particular in the initial phase. Ang-2 enhanced the initial permeability increase (passage, P = 0.010; TEER, P = 0.021) in parallel with impairment of VE-cadherin organization without affecting VE-cadherin Tyr685 phosphorylation or increasing RhoA activity. Ang-2 also increased intercellular gap formation. Ang-1 preincubation increased Rac1 activity, enforced the VE-cadherin organization, reduced the initial thrombin-induced permeability (TEER, P = 0.027), while Rac1 activity simultaneously normalized, and reduced RhoA activity at 15 min thrombin exposure (P = 0.039), but not at earlier time points. The simultaneous presence of Ang-2 largely prevented the effect of Ang-1 on TEER and macromolecule passage. Conclusions/Significance Ang-1 attenuated thrombin-induced permeability, which involved initial Rac1 activation-enforced cell-cell junctions, and later RhoA inhibition. In addition to antagonizing Ang-1, Ang-2 had also a direct effect itself. Ang-2 sensitized the initial thrombin-induced permeability accompanied by destabilization of VE-cadherin junctions and increased gap formation, in the absence of increased RhoA activity.
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