294 research outputs found
Vegetation composition and soil microbial community structural changes along a wetland hydrological gradient
Fluctuations in wetland hydrology create an interplay between aerobic and anaerobic conditions, controlling vegetation composition and microbial community structure and activity in wetland soils. In this study, we investigated the vegetation composition and microbial community structural and functional changes along a wetland hydrological gradient. Two different vegetation communities were distinguished along the hydrological gradient; <i>Caricetum gracilis</i> at the wet depression and <i>Arrhenatheretum elatioris</i> at the drier upper site. Microbial community structural changes were studied by a combined in situ <sup>13</sup>CO<sub>2</sub> pulse labeling and phospholipid fatty acid (PLFA) based stable isotope probing approach, which identifies the microbial groups actively involved in assimilation of newly photosynthesized, root-derived C in the rhizosphere soils. Gram negative bacterial communities were relatively more abundant in the surface soils of the drier upper site than in the surface soils of the wetter lower site, while the lower site and the deeper soil layers were relatively more inhabited by gram positive bacterial communities. Despite their large abundance, the metabolically active proportion of gram positive bacterial and actinomycetes communities was much smaller at both sites, compared to that of the gram negative bacterial and fungal communities. This suggests much slower assimilation of root-derived C by gram positive and actinomycetes communities than by gram negative bacteria and fungi at both sites. Ground water depth showed a significant effect on the relative abundance of several microbial communities. Relative abundance of gram negative bacteria significantly decreased with increasing ground water depth while the relative abundance of gram positive bacteria and actinomycetes at the surface layer increased with increasing ground water depth
Images of Coordination: How Implementing Organizations Perceive Coordination Arrangements
A crucial challenge for the coordination of horizontal policy programs—those designed to tackle crosscutting issues—is how to motivate government organizations to contribute to such programs. Hence, it is crucial to study how practitioners in implementing organizations view and appreciate the coordination of such programs. Assisted by Q-methodology, this inductive study reveals three significantly different “images”: central frame setting, networking via boundary spanners, and coordination beyond window dressing. Most surprisingly, different images show up among respondents within the same organizations and horizontal programs. The authors find that the images reflect elements of the literature: the resistance to hierarchical central control, the need for local differentiation and increased incentives, and a collaboration-oriented culture. Most importantly, practitioners of implementing organizations perceive top-down mechanisms as ineffective to achieve coordination and ask for adaptive arrangements, involvement, and deliberative processes when designing coordination arrangements and during the collaboration
Calibration of the modified Bartlett-Lewis model using global optimization techniques and alternative objective functions
The calibration of stochastic point process rainfall models, such as of the Bartlett-Lewis type, suffers from the presence of multiple local minima which local search algorithms usually fail to avoid. To meet this shortcoming, four relatively new global optimization methods are presented and tested for their ability to calibrate the Modified Bartlett-Lewis Model. The list of tested methods consists of: the Downhill Simplex Method, Simplex-Simulated Annealing, Particle Swarm Optimization and Shuffled Complex Evolution. The parameters of these algorithms are first optimized to ensure optimal performance, after which they are used for calibration of the Modified Bartlett-Lewis model. Furthermore, this paper addresses the choice of weights in the objective function. Three alternative weighing methods are compared to determine whether or not simulation results (obtained after calibration with the best optimization method) are influenced by the choice of weights
DBFM(O)contracten in de publieke infrastrcutuur in Nederland en Belgie
Op 22 november 2016 vond er in Antwerpen aan de Universiteit van Antwerpen een internationaal
wetenschappelijk congres plaats over publiek-private samenwerking.
In haar rol als facilitator en kennisontwikkelaar nam het Kenniscentrum PPS van de Vlaamse overheid
(Vlaams Kenniscentrum PPS) haar rol op om samen met de organiserende partners van het congres in de
schoot van dit congres een conferentie op te zetten waar PPS-beoefenaars en wetenschappers met elkaar in
dialoog konden gaan.
Deze dialoog kreeg verder vorm door een samenwerking tussen verschillende universiteiten, en door de
ondersteuning van diverse overheden en bedrijven in Vlaanderen en Nederland. In die zin was het zelf ook
een vorm van publiek-private samenwerking.
In deze publicatie blikken we terug op dit succesvolle seminarie en laten we u proeven van de talrijke interessante
reflecties als stof tot nadenken. De organisatoren van het congres en de editors van deze publicatie hopen dat
de teksten het debat over PPS kunnen voeden, en dat het werk een bijdrage kan leveren tot een verdere
professionalisering en tot innovaties in de PPS-praktijk en het onderzoek van morgen
The atypical anxiolytic drug, tofisopam, selectively blocks phosphodiesterase isoenzymes and is active in the mouse model of negative symptoms of psychosis
Tofisopam is a member of the 2,3-benzodiazepine compound family which is marketed for the treatment of anxiety in some European countries. In contrast to classical 1,4-benzodiazepines, the compound does not bind to the benzodiazepine binding site of the γ-aminobutyric acid receptor and its psychopharmacological profile differs from such compounds. In addition to anxiolytic properties, antipsychotic effects are reported. We now show that tofisopam, 50 mg/kg intraperitoneally (i.p.), administered in parallel to repeated doses of dizocilpine 0.2 mg/kg i.p. can ameliorate dizocilpine-induced prolongation of immobility, which is considered to be a model of negative symptoms of psychosis. We further show that tofisopam acts as an isoenzyme-selective inhibitor of phosphodiesterases (PDEs) with highest affinity to PDE-4A1 (0.42 μM) followed by PDE-10A1 (0.92 μM), PDE-3 (1.98 μM) and PDE-2A3 (2.11 μM). The data indicate that tofisopam is an interesting candidate for the adjuvant treatment of psychosis with focus on negative symptoms. Combined partial inhibition of PDE-4 and PDE-10 as well as PDE-2 may be the underlying mechanism to this activity. Due to the good safety profile of tofisopam as evident from long-term use of this agent in patients, it may be concluded that dual or triple inhibition of PDE isoenzymes with additive or synergistic effects may be an interesting approach to pharmacological activity, resulting in active compounds with beneficial safety profile. Dose-limiting side effects such as emesis induced by selective inhibition of PDE-4 may be prevented by such strategies
Municipal service delivery: the role of transaction costs in the choice between alternative governance mechanisms
Service provision by local governments can be delivered using in-house bureaucracies, private firms, and partnerships with other governments or the not-for-profit sector. This production decision has been a major focus of discussion among scholars, practitioners and political agents for the last quarter of a century. The transaction costs framework is an important tool to analyse decisions regarding the production of local services. In this paper, the authors employ this framework to analyse service delivery in Portugal and find that service characteristics and the local political environment play a key role in local officials’ choice among the three governance mechanisms to deliver public service
Tumoral CD105 is a novel independent prognostic marker for prognosis in clear-cell renal cell carcinoma
International audienceBackground: Angiogenesis is essential for tumour growth and metastasis. There are conflicting reports as to whether microvessel density (MVD) using the endothelial marker CD105 (cluster of differentiation molecule 105) in clear-cell renal cell carcinomas (ccRCC) is associated with prognosis. Recently, CD105 has been described as a RCC cancer stem cell marker.Methods: A total of 102 ccRCC were analysed. Representative tumour sections were stained for CD105. Vascularity (endothelial CD105) was quantified by MVD. The immunohistochemistry analysis detected positive (if present) or negative (if absent) CD105 tumoral staining. This retrospective population-based study was evaluated using Kaplan–Meier method, t-test and Cox proportional hazard model.Results: We found that the expression of endothelial CD105 (MVD) negatively correlated with nuclear grade (P<0.001), tumour stage (P<0.001) and Leibovitch score (P<0.001), whereas the expression of tumoral CD105 positively correlated with these three clinicopathological factors (P<0.001). In multivariate analysis, tumoral CD105 was found to be an independent predictor of poor overall survival (P=0.002).Conclusions: We have shown for the first time that tumoral CD105 is an independent predictive marker for death risk and unfavourable prognosis in patients with ccRCC after curative resection
Stochastic simulation of precipitation-consistent daily reference evapotranspiration using vine copulas
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