456 research outputs found
Ecologische monitoring in het kader van het Masterplan Kustveiligheid: Middelkerke (t1‐situatie): Eindrapport
Investigating the combined effects of climate change on ecophysiological response of offshore wind farm fouling fauna
Organism-sediment interactions govern post-hypoxia recovery of ecosystem functioning
Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning.
The structure and functional roles of tidal flat meiobenthos
Meiofauna comprise the smallest multicellular and largest unicellular metazoans in benthic food webs. They are highly abundant and species-rich, yet essential aspects of the factors driving their community structure and abundance remain poorly understood. Similarly, their functional roles in benthic carbon cycling remain poorly characterized and even more poorly quantified. In the frame of two projects, we addressed questions regarding both the biotic and abiotic factors that drive meiobenthic assemblage structure, and their roles in benthic carbon cycling. Our research involved an intricate combination of manipulative laboratory experiments and field work, the latter mostly focusing on the intertidal flats bordering the Paulina salt marsh in the Scheldt estuary. The results add considerably to our understanding of the factors that drive meiobenthic assemblage structure. They clearly demonstrate that biotic interactions among different meiofauna, and between meio- and macrofauna, are extremely important and moderate the impacts of prominent abiotic drivers of assemblage structure such as granulometry and oxygen availability. From a functional point of view, we demonstrated that tidal flat meiofauna rely predominantly on carbon derived from in situ primary production by microphytobenthos. Quantification of grazing rates of meiofauna on microphytobenthos and benthic bacteria does not, however, point at an important direct contribution of meiofauna to benthic carbon cycling. The role of meiobenthic species diversity remains to be established, but laboratory experiments into the role of nematodes in OM decomposition reveal that in addition to species identity, species diversity does have a significant, yet largely unpredictable effect on OM decomposition rates
Reaching for the stars: When does basic research collaboration between firms and academic star scientists benefit firm invention performance?
While their expertise and scientific excellence make academic star scientists attractive collaboration partners for firms, this study indicates that firms face difficulties in capturing value from collaborations with academic stars. Stars are time constrained, may be less committed to commercialization, and can be a source of undesired knowledge spillovers to other firms. The purpose of this study is to recognize the contingencies under which collaboration with star scientists is positively associated with a firm's ability to produce valuable patents (invention performance). We analyze a panel data set on the collaborations in basic research (publication data) and invention performance (patent output) of 60 prominent pharmaceutical firms. We find that basic research collaboration with academic stars is on average not associated with a performance premium above the overall positive influence of collaborating with academia. We only observe this premium if the star scientist abstains from simultaneous collaboration with other firms (‘dedication’) and extend her collaboration with the firm to involve not only basic but also applied research (‘translation’). Extending prior work that has focused on corporate star scientists, we find that if the collaboration involves an internal firm star scientist, a translational contribution of the academic star is no longer a prerequisite, and may even be detrimental to inventive performance. Our findings inform the literatures on industry-science links and firms’ (scientific) absorptive capacity by revealing the crucial contingencies for firms to benefit from partnering with the best and brightest among academic scientists
Mir-21-Sox2 Axis Delineates Glioblastoma Subtypes with Prognostic Impact.
UNLABELLED: Glioblastoma (GBM) is the most aggressive human brain tumor. Although several molecular subtypes of GBM are recognized, a robust molecular prognostic marker has yet to be identified. Here, we report that the stemness regulator Sox2 is a new, clinically important target of microRNA-21 (miR-21) in GBM, with implications for prognosis. Using the MiR-21-Sox2 regulatory axis, approximately half of all GBM tumors present in the Cancer Genome Atlas (TCGA) and in-house patient databases can be mathematically classified into high miR-21/low Sox2 (Class A) or low miR-21/high Sox2 (Class B) subtypes. This classification reflects phenotypically and molecularly distinct characteristics and is not captured by existing classifications. Supporting the distinct nature of the subtypes, gene set enrichment analysis of the TCGA dataset predicted that Class A and Class B tumors were significantly involved in immune/inflammatory response and in chromosome organization and nervous system development, respectively. Patients with Class B tumors had longer overall survival than those with Class A tumors. Analysis of both databases indicated that the Class A/Class B classification is a better predictor of patient survival than currently used parameters. Further, manipulation of MiR-21-Sox2 levels in orthotopic mouse models supported the longer survival of the Class B subtype. The MiR-21-Sox2 association was also found in mouse neural stem cells and in the mouse brain at different developmental stages, suggesting a role in normal development. Therefore, this mechanism-based classification suggests the presence of two distinct populations of GBM patients with distinguishable phenotypic characteristics and clinical outcomes.
SIGNIFICANCE STATEMENT: Molecular profiling-based classification of glioblastoma (GBM) into four subtypes has substantially increased our understanding of the biology of the disease and has pointed to the heterogeneous nature of GBM. However, this classification is not mechanism based and its prognostic value is limited. Here, we identify a new mechanism in GBM (the miR-21-Sox2 axis) that can classify ∼50% of patients into two subtypes with distinct molecular, radiological, and pathological characteristics. Importantly, this classification can predict patient survival better than the currently used parameters. Further, analysis of the miR-21-Sox2 relationship in mouse neural stem cells and in the mouse brain at different developmental stages indicates that miR-21 and Sox2 are predominantly expressed in mutually exclusive patterns, suggesting a role in normal neural development
Toward the Sustainable and Efficient Use of External Thermal Insulation Composite Systems (ETICS): A Comprehensive Review of Anomalies, Performance Parameters, Requirements and Durability
The identification of the main degradation agents and knowledge of the degradation mechanisms and long-term performance of ETICSs are of fundamental importance for the sustainable and efficient use of these systems. This review article presents the state of the art related to the durability of ETICSs, defining the required bases for their sustainable and efficient use. The aim is to identify the most common anomalies detected on ETICS façades and their causes, to overview the performance of ETICS, their performance parameters and requirements and to identify the most significant degradation mechanisms and the related failure modes. The results show that ETICS application is a key aspect in the performance and durability of the system, since most of the anomalies can be prevented with proper design, execution and appropriate assembly of the system components. The greatest drawbacks lie in dealing with enhancing the water resistance over time, which leads to extensive cases of anomalies, and improving the mechanical and thermal performance during the life cycle. Further research is needed to evaluate the synergistic effect of several degradation agents and mechanisms toward a development in optimized durability assessment methodologies for ETICSs.info:eu-repo/semantics/publishedVersio
Childbearing postponement and child well-being: a complex and varied relationship?
Over the past several decades, U.S. fertility has followed a trend toward the postponement of motherhood. The socioeconomic causes and consequences of this trend have been the focus of attention in the demographic literature. Given the socioeconomic advantages of those who postpone having children, some authors have argued that the disadvantage experienced by certain groups would be reduced if they postponed their births. The weathering hypothesis literature, by integrating a biosocial perspective, complicates this argument and posits that the costs and benefits of postponement may vary systematically across population subgroups. In particular, the literature on the weathering hypothesis argues that as a consequence of their unique experiences of racism and disadvantage, African American women may experience a more rapid deterioration of their health, which could offset or eventually reverse any socioeconomic benefit of postponement. But because very few African American women postpone motherhood, efforts to find compelling evidence to support the arguments of this perspective rely on a strategy of comparison that is problematic because a potentially selected group of older black mothers are used to represent the costs of postponement. This might explain why the weathering hypothesis has played a rather limited role in the way demographers conceptualize postponement and its consequences for well-being. In order to explore the potential utility of this perspective, we turn our attention to the UK context. Because first-birth fertility schedules are similar for black and white women, we can observe (rather than assume) whether the meaning and consequences of postponement vary across these population subgroups. The results, obtained using linked UK census and birth record data, reveal evidence consistent with the weathering hypothesis in the United Kingdom and lend support to the arguments that the demographic literature would benefit from integrating insights from this biosocial perspective
A morphological study of retinal changes in unilateral amblyopia using optical coherence tomography image segmentation.
OBJECTIVE: The purpose of this study was to evaluate the possible structural changes of the macula in patients with unilateral amblyopia using optical coherence tomography (OCT) image segmentation. PATIENTS AND METHODS: 38 consecutive patients (16 male; mean age 32.4+/-17.6 years; range 6-67 years) with unilateral amblyopia were involved in this study. OCT examinations were performed with a time-domain OCT device, and a custom-built OCT image analysis software (OCTRIMA) was used for OCT image segmentation. The axial length (AL) was measured by a LenStar LS 900 device. Macular layer thickness, AL and manifest spherical equivalent refraction (MRSE) of the amblyopic eye were compared to that of the fellow eye. We studied if the type of amblyopia (strabismus without anisometropia, anisometropia without strabismus, strabismus with anisometropia) had any influence on macular layer thickness values. RESULTS: There was significant difference between the amblyopic and fellow eyes in MRSE and AL in all subgroups. Comparing the amblyopic and fellow eyes, we found a statistically significant difference only in the thickness of the outer nuclear layer in the central region using linear mixed model analysis keeping AL and age under control (p = 0.032). There was no significant difference in interocular difference in the thickness of any macular layers between the subgroups with one-way between-groups ANCOVA while statistically controlling for interocular difference in AL and age. CONCLUSIONS: According to our results there are subtle changes in amblyopic eyes affecting the outer nuclear layer of the fovea suggesting the possible involvement of the photoreceptors. However, further studies are warranted to support this hypothesis
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