235130 research outputs found
Sort by
First indications for reduced mortality of non-target invertebrate benthic megafauna after pulse beam trawling
No full textTwo alternative stimulation techniques to reduce mortality in benthic megafauna were tested relative to standard tickler chain beam trawling:longitudinal electrodes (pulse trawl) and longitudinal chains. Longitudinal chains caused higher mortality than pulse trawling in 3 species. Standard trawling gave higher mortality in Echinocardium cordatum than pulse trawling. Between longitudinal chain and standard trawling were no significant differences. This trend in decreasing mortality from longitudinal, to standard and then pulse trawling was confirmed by a similar decline in: i) numbers of significant species mortalities per trawl type, ii) average mortalities, i.e. longitudinal chain caused 41% more mortality than standard trawling and pulse trawling 43% less, iii) pre- and post-trawling community dissimilarities. A significant majority of species showed higher mortalities after longitudinal than after standard trawling and, conversely, lower mortalities after pulse trawling. Trawls with longitudinal chains instead of cross tickler chains increase megafaunal impact. On the contrary, pulse trawling can reduce the impact, although average mortality remains substantial (25%) even in impoverished benthic test assemblages in the southern North Sea. Power, generally was low and reference areas, free of (pulse) trawling, and inhabited by more vulnerable taxa will facilitate higher powered studies on the impact of standard and alternative trawling techniques
Efectos de poda y fertilización en los rendimientos de jatropha bajo condiciones de pequeños agricultores en un bosque seco tropical de ecuador
No full textJatropha seed is a biomass suitable for bioenergy production that can be produced by smallholders, even on marginal lands. However, the current oilseed production is too low to meet the needs of the planned renewable electricity system in the Galapagos Islands. Pruning and fertilization are management options that can be used to increase the dry seed yields. The effects of both treatments were tested in a split-plot design with jatropha trees, which were monitored during a three-year production period. The average seed production was 643±58 kg ha-1 year-1 in the unpruned trees and 696±50 kg ha-1 year-1 in the pruned trees. Although this difference is small, it is expected to increase over time. The pruned trees developed more slowly than the unpruned trees but showed higher (and still increasing) yields at the end of the three-year test period, while the unpruned trees appeared to have reached their maximum production by the second year of the trial. The low fertilizer doses approved by the smallholders did not have a significant impact on the dry seed yield, and the management options that show benefits in the long term are generally not accepted or adopted by them. Cost-effective nutrient enhancement should be investigated, such as inoculation with arbuscular mycorrhizal fungi.</p
Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) – 16S data set
No full textMetagenomic 16S amplicon sequencing data for 79 children included in the Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) study, an open-label trial during which children with ADHD followed a few-foods diet (FFD). Sampling was done during screening (t0), before the FFD (t1) and after 5 weeks of FFD (t2)
Wintersterfte van bijenvolken 2018-2019 : Resultaten enquête wintersterfte bijenvolken in Nederland in de winter van 2018-2019
Get PDFSinds 2003 wordt in Nederland jaarlijks de wintersterfte van bijenvolken gemonitord. Dit geeft een indicatie van de gezondheidstoestand van de gehouden populatie honingbijen in Nederland. Aan de wintersterfte-enquête van 2018-2019 deden 2032 bijenhouders mee. Dit is ongeveer 20% van alle bijenhouders in Nederland in 2018. De enquête bestond uit 3 gedeeltes, het eerste gedeelte ging over de gegevens van de bijenhouder, het tweede gedeelte over de bepaling van de wintersterfte en het laatste gedeelte was de COLOSS-enquête met een aantal toegevoegde vragen die relevant zijn voor de Nederlandse bijenhouderij. De wintersterfte van bijenvolken in Nederland in de winter van 2018-2019 was 9,2%. Dit is lager dan de twee voorgaande winters (14,3% en 15,7%). Van de respondenten gaf 69% te kennen geen wintersterfte van bijenvolken te hebben gehad in 2018-2019. Van diegene met sterfte van volken in de winter, gaf 68% te kennen koninginnenproblemen als oorzaak van de sterfte te zien. Verder werd berekend dat bijenhouders in Nederland gemiddeld genomen 8 bijenvolken hadden in 2018 en dat de totaalpopulatie gehouden bijenvolken ongeveer 75.000 bijenvolken bedroeg (najaar 2018). Per volk werd gemiddeld 13 kg honing geoogst. Per respondent was de gemiddelde honingopbrengst 101kg in 2018. Een gemiddelde prijs van €7,71 werd gevraagd voor een kilo honing en de respondenten hadden gemiddeld €448,- aan productiekosten. Het overgrote deel van de respondenten (88%) gaf te kennen varroa te bestrijden en de meerderheid (60%) monitort de varroabesmetting op enigerlei wijze. De resultaten van de COLOSS-enquête worden in internationaal verband geanalyseerd en vergeleken met de resultaten uit andere landen. In totaal doen zo’n 35 landen mee aan de COLOSS-enquête. De resultaten worden in de loop van 2020 ter publicatie aan een wetenschappelijk tijdschrift aangeboden
Four paradoxes of the user-provider interface: A responsible innovation framework for sea ice services
Get PDFIn the Arctic region, sea ice retreat as a decadal-scale crisis is creating a challenging environment for navigating long-term sustainability. Innovations in sea ice services can help marine users to anticipate sea ice concentration, thickness and motion, plan ahead, as well as increase the safety and sustainability of marine operations. Increasingly however, policy makers and information service providers confront paradoxical decision-making contexts in which contradictory solutions are needed to manage uncertainties across different spatial and temporal scales. This article proposes a forward-looking sea ice services framework that acknowledges four paradoxes pressuring sea ice service provision: the paradoxes of performing, contradictory functions embedded in sea ice services, contradicting desired futures and the paradox of responsible innovation. We draw on the results from a multi-year co-production process of (sub)seasonal sea ice services structured around scoping interviews, workshops and a participatory scenario process with representatives of marine sectors, fishers, hunters, metservice providers, and policy experts. Our proposed framework identifies institutionalized coproduction processes, enhanced decision support, paradoxical thinking and dimensions of responsible innovation as tactics necessary to address existing tensions in sea ice services. We highlight the role of socio-economic scenarios in implementing these tactics in support of responsible innovation in sea ice social-ecological systems. The article concludes with a discussion of questions around equity and responsibility raised by the ultimate confirmation that enhanced information, data infrastructures, and service provisions will not benefit all actors equally.</p
The political imaginaries of blockchain projects: discerning the expressions of an emerging ecosystem
Get PDFThere is a wealth of information, hype around, and research into blockchain’s ‘disruptive’ and ‘transformative’ potential concerning every industry. However, there is an absence of scholarly attention given to identifying and analyzing the political premises and consequences of blockchain projects. Through digital ethnography and participatory action research, this article shows how blockchain experiments personify ‘prefigurative politics’ by design: they embody the politics and power structures which they want to enable in society. By showing how these prefigurative embodiments are informed and determined by the underlying political imaginaries, the article proposes a basic typology of blockchain projects. Furthermore, it outlines a frame to question, cluster, and analyze the expressions of political imaginaries intrinsic to the design and operationalization of blockchain projects on three analytic levels: users, intermediaries, and institutions.</p
Chrono-nutrition and diet quality in adolescents with delayed sleep-wake phase disorder
Get PDFBackground: Delayed sleep-wake phase disorder (DSPD), characterized by delayed sleep-onset and problems with awakening in the morning, is mostly prevalent in adolescents. Several studies have suggested chrono-nutrition could present a possible modifiable risk factor for DSPD. Objective: To describe differences in chrono-nutrition and diet quality in adolescents with DSPD compared to age-related controls. Methods: Chrono-nutrition and diet quality of 46 adolescents with DSPD, aged 13–20 years, and 43 controls were assessed via questionnaires. Diet quality included the Dutch Healthy Diet index (DHD-index) and Eating Choices Index (ECI). Results were analysed using logistic regression and Spearman’s partial correlation. Results: Compared with controls, DSPD patients consumed their first food of the day significantly later on weekdays (+32 ± 12 min, p = 0.010) and weekends (+25 ± 8 min, p = 0.005). They consumed their dinner more regularly (80.4% vs. 48.8%, p = 0.002) and consumed morning-snacks less frequently (3.0 ± 2.1 days vs. 4.2 ± 1.7 days, p = 0.006). No differences in clock times of breakfast, lunch, or dinner were found. Moreover, no significant differences in overall diet quality were observed. Conclusion: This descriptive study showed chrono-nutritional differences between adolescents with and without DPSD. Further studies are needed to explore features of chrono-nutrition as a possible treatment of DPSD.</p
Closing yield gaps in oil palm production systems in Ghana through Best Management Practices
Get PDFThe area under oil palm in Ghana has expanded but average fruit bunch yields remained low, resulting in large yield gaps. This study assessed the potential for increasing yield with 'Best Management Practices (BMP)' on plantations and smallholder farms in southern Ghana, compared with current standard practices, i.e. reference (REF) yield. We evaluated short-term (≤1 year) yield increases with 'yield taking' (improved crop recovery), and long-term increases (>1 year) with 'yield making' (better agronomy) practices and identified the factors that contributed most to yield improvements. Average fruit bunch yield increases with BMP were 2.1 t ha−1 (+19%) and 4.7 t ha−1 (+89%) with yield taking and 4.7 t ha−1 (+36%) and 7.6 t ha−1 (+76%) with yield making at plantations and smallholder farms respectively. Short-term yield improvements were achieved with more frequent harvesting events and improved field access, which can help finance inputs needed for the yield making phase. Our analysis suggests more balanced palm nutrition could contribute considerably to yield making, particularly on smallholder farms. Improved fertilizer recommendations are therefore essential for sustainable oil palm production in Ghana. Increasing yields to 21.0 t ha−1 on land already planted to oil palm, can increase national fruit bunch production from 2.5 Mt to 6.9 Mt, sparing 600,000 ha of land. However, labour constraints on plantations and lack of access to credit and agricultural inputs on smallholder farms are major hurdles that need to be overcome to increase production.</p
Examining effects of climate change and land use dynamic on biophysical and economic values of ecosystem services of a natural reserve region
No full textEcosystem Service Valuation (ESV) is a process of evaluating and quantifying the monetary values of ESs and their functions. Using both biophysical and spatially explicit integrated models, biophysical and monetary values of key Ecosystem Services (ESs) were estimated in the Sundarbans Biosphere Region (SBR), India. Quantification was made both in time series (1982–2017) and individual years (1973, 1988, 2003, 2013, 2018, 2025, 2035, 2045) to understand the impact of climate change and land-use dynamics on the long-term ecological status of the region. The monetary and biophysical values of the ESs were then obtained from Net Primary Productivity (NPP) models, Integrated Valuation of Ecosystem Services and Trade-offs (InVEST), and Cellular Automata Markov Chain Model (CA-Markov). NPP increased significantly during the first half period (1982–1999), but significantly declined during the second period (2000–2017). The highest estimated ESVs (US$ ha−1) was found for habitat service (30780), nutrient cycling (12626), and gas regulation (7224.81), whereas, lower ESVs were approximated for water regulation (347.81), raw material production (777.82) and waste treatment (13.57) services. Among the nine ESs evaluated, climate regulation, gas regulation, and disturbance regulation were the most important regulating services of the SBR. The combined effects of climate change and land-use dynamics on ESs are much stringent in a vulnerable region like the SBR. Most of the regulating services were closely associated with the fluctuation of land use land cover input. Thus, land management policies and land reform strategies that will encourage the conversion of productive land, especially the highly productive mangrove forest, for the development or any other financial benefits, would disturb the ideal human-nature balance of this ecosystem. The outcomes of this study also provide an important reference to the land administrators, researchers, and decision-makers to comprehend the expected social-ecological juxtaposition in a protected natural reserve region like the Sundarbans.</p
Impact of polystyrene nanoparticles on marine diatom Skeletonema marinoi chain assemblages and consequences on their ecological role in marine ecosystems
No full textMarine diatoms have been identified among the most abundant taxa of microorganisms associated with plastic waste collected at sea. However, the impact of nano-sized plastic fragments (nanoplastics) at single cell and population level is almost unknown. We exposed the marine diatom Skeletonema marinoi to model polystyrene nanoparticles with carboxylic acid groups (PS–COOH NPs, 90 nm) for 15 days (1, 10, 50 μg/mL). Growth, reactive oxygen species (ROS) production, and nano-bio-interactions were investigated. No effect on diatom growth was observed, however Dynamic light scattering (DLS) demonstrated the formation of large PS aggregates which were localized at the diatoms’ fultoportula process (FPP), as shown by TEM images. Increase production of ROS and reduction in chain length were also observed upon PS NPs exposure (p < 0.005). The observed PS-diatom interaction could have serious consequences on diatoms ecological role on the biogeochemical cycle of carbon, by impairing the formation of fast-sinking aggregates responsible for atmospheric carbon fixation and sequestration in the ocean sea floor. S. marinoi exposure to PS NPs caused an increase of intracellular and extracellular oxidative stress, the reduction of diatom's chain length and the adhesion of PS NPs onto the algal surface