Search

Genetic association results are often interpreted with the assumption that study participation does not affect downstream analyses. Understanding the genetic basis of participation bias is challenging since it requires the genotypes of unseen individuals. Here we demonstrate that it is possible to estimate comparative biases by performing a genome-wide association study contrasting one subgroup versus another. For example, we showed that sex exhibits artifactual autosomal heritability in the presence of sex-differential participation bias. By performing a genome-wide association study of sex in approximately 3.3 million males and females, we identified over 158 autosomal loci spuriously associated with sex and highlighted complex traits underpinning differences in study participation between the sexes. For example, the body mass index-increasing allele at FTO was observed at higher frequency in males compared to females (odds ratio = 1.02, P = 4.4 × 10-36). Finally, we demonstrated how these biases can potentially lead to incorrect inferences in downstream analyses and propose a conceptual framework for addressing such biases. Our findings highlight a new challenge that genetic studies may face as sample sizes continue to grow.

The central aim of the study, “The fate of (compostable) plastic products in a full scale industrial organic waste treatment facility,” was to gather more empirical data on whether the disintegration rate of compostable products is sufficient to be compatible with current organic waste treatment practices in the Netherlands. In an industrial organic waste treatment trial, nine different compostable plastic products were tested: organic waste collection bags, plant pots, tea bags, coffee pads, coffee capsules, and fruit labels. The authors studied how compostable plastics behave in the current Dutch treatment system for source separated municipal organic waste (GFT) and came to the conclusion that compostable products can be processed well with GFT. Part II of this article discusses the results of the full-scale trials.

The central aim of the study, “The fate of (compostable) plastic products in a full scale industrial organic waste treatment facility,” was to gather more empirical data on whether the disintegration rate of compostable products is sufficient to be compatible with current organic waste treatment practices in the Netherlands. In an industrial organic waste treatment trial, nine different compostable plastic products were tested: organic waste collection bags, plant pots, tea bags, coffee pads, coffee capsules, and fruit labels. The authors studied how compostable plastics behave in the current Dutch treatment system for source separated municipal organic waste (GFT) and came to the conclusion that compostable products can be processed well with GFT. Part I of this article summarizes the scope and research methods.

Background: Having conquered water surfaces worldwide, the semi-aquatic bugs occupy ponds, streams, lakes,mangroves, and even open oceans. The diversity of this group has inspired a range of scientific studies fromecology and evolution to developmental genetics and hydrodynamics of fluid locomotion. However, the lack of arepresentative water strider genome hinders our ability to more thoroughly investigate the molecular mechanismsunderlying the processes of adaptation and diversification within this group.

Public summaryWork package 5In situ biodegradationDeliverable N° 5.7

Public summaryWork package 5In situ biodegradationDeliverable N° 5.9

Public summaryWork package 6Managed end-of-life optionsDeliverable N° 6.8

Work package 5. In situ biodegradation Deliverable N° 5.6: Validation of lab and mesocosm tests against field experiments

Can stable isotopes be used to determine the bio-based content of products?

Public reportWork package 5In situ biodegradationDeliverable N°5.5

Public reportWork package 6BiodegradabilityDeliverable N° 6.5

The main objective of the trial was to be able to judge whether BioFoam® material degrades at sufficient rate to be composted together with regular source separated municipal solid biowaste in a full scale industrial composting facility.

This paper considers the impact of tidal forcing on regional groundwater flow in an unconfined coastal aquifer. Numerical models are used to quantify this impact for a wide range of hydrogeological conditions. Both a shallow and a deep aquifer are investigated with regard to three dimensionless parameter groups that determine the groundwater flow to a large extent. Analytical expressions are presented that allow for a quick estimate of the regional scale effect of tidal forcing under the same conditions as used in the numerical models. Quantitatively, the results in this paper are complementary to previous studies by taking into account variable density groundwater flow, dispersive salt transport and a seepage face in the intertidal area. Qualitatively, the results are in line with previous investigations. The time-averaged hydraulic head at the high tide mark increases upon a decrease of each of the three considered dimensionless parameter groups: R (including the ratio of the hydraulic conductivity and the precipitation excess), alpha (the slope of the intertidal area) and A(L) (the ratio of the width of the fresh water lens and the tidal amplitude). The relative change of the location and the hydraulic head of the groundwater divide, which together characterize regional groundwater flow, increase as alpha and A(L) decrease, but decrease as R decreases. The difference between the analytical solutions and numerical results is small. Therefore, the presented analytical solutions can be used to estimate the bias that is introduced in a numerical model if tidal forcing is neglected. The results should be used with caution in case of significant wave forcing, as this was not considered.

Dit rapport beschrijft de resultaten van een haalbaarheidsstudie naar de technische en economische haalbaarheid en implicaties van een verbod op dunne plastic draagtasjes in Nederland, met een eventuele uitzondering voor bioplastic draagtassen. In deze korte studie staan bioplastic draagtassen centraal. Het gaat hierbij om alle bioplastics, dus om zowel de biologisch afbreekbare plastics als om niet-biologisch afbreekbaar bioplastic zoals biobased polyetheen (bio-PE). Het is technisch haalbaar om conventioneel fossiele PE plastic draagtassen te vervangen door bioplastic draagtassen. Bio-PE heeft dezelfde eigenschappen als fossiel PE en kan derhalve 1 op 1 als vervanging dienen. Biologisch afbreekbare plastic draagtassen voldoen eveneens; ze zijn vooralsnog dikker en zwaarder dan PE draagtassen om aan de gebruikerseisen te voldoen. Een specifieke antwoord op de economische en technische effecten is niet te geven omdat de exacte beleidsmaatregel en met name daaraan ten grondslag liggende beoogde effecten nog niet duidelijk is. In dit rapport worden daarom verschillende elementen besproken die onderdeel kunnen worden van een eventuele beleidsmaatregel.

BPM magazine is een uitgave van het Biobased Performance Materials programma. In dit programma werken kennisinstellingen en bedrijven samen aan nieuwe biobased plastics en aan toepassingsgericht onderzoek om de eigenschappen van bestaande biokunststoffen te verbeteren.

The genome of the pea aphid shows remarkable levels of gene duplication and equally remarkable gene absences that shed light on aspects of aphid biology, most especially its symbiosis with Buchnera., Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems., Author Summary Aphids are common pests of crops and ornamental plants. Facilitated by their ancient association with intracellular symbiotic bacteria that synthesize essential amino acids, aphids feed on phloem (sap). Exploitation of a diversity of long-lived woody and short-lived herbaceous hosts by many aphid species is a result of specializations that allow aphids to discover and exploit suitable host plants. Such specializations include production by a single genotype of multiple alternative phenotypes including asexual, sexual, winged, and unwinged forms. We have generated a draft genome sequence of the pea aphid, an aphid that is a model for the study of symbiosis, development, and host plant specialization. Some of the many highlights of our genome analysis include an expanded total gene set with remarkable levels of gene duplication, as well as aphid-lineage-specific gene losses. We find that the pea aphid genome contains all genes required for epigenetic regulation by methylation, that genes encoding the synthesis of a number of essential amino acids are distributed between the genomes of the pea aphid and its symbiont, Buchnera aphidicola, and that many genes encoding immune system components are absent. These genome data will form the basis for future aphid research and have already underpinned a variety of genome-wide approaches to understanding aphid biology.

Dit rapport heeft tot doel een overzicht te geven van de voor Nederland belangrijkste activiteiten en bedrijfsplannen betreffende algen die nationaal en internationaal gaande zijn c.q. gemaakt worden. Er wordt een overzicht gegeven van organisaties die zich bezig houden met (toepassing van) algenteelt, onderverdeeld in Nederlandse (of in Nederland opererende) en buitenlandse organisaties. Er is ook een overzicht van projecten met Nederlandse inbreng op het gebied van (toepassing van) algenteelt. De projecten zijn gerangschikt in lopende grote, middelgrote, en kleine projecten, en in het oog springende initiatieven om tot een project te komen. Tot slot worden een paar algemene conclusies en aanbevelingen gegeven voor de korte en lange termijn.

Lit.opg.

Met lit. opg

Tribolium castaneum is a member of the most species-rich eukaryotic order, a powerful model organism for the study of generalized insect development, and an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved the ability to interact with a diverse chemical environment, as shown by large expansions in odorant and gustatory receptors, as well as P450 and other detoxification enzymes. Development in Tribolium is more representative of other insects than is Drosophila, a fact reflected in gene content and function. For example, Tribolium has retained more ancestral genes involved in cell-cell communication than Drosophila, some being expressed in the growth zone crucial for axial elongation in short-germ development. Systemic RNA interference in T. castaneum functions differently from that in Caenorhabditis elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control.

Dit boekje heeft als doel een overzicht te schetsen over nieuwe composteerbare verpakkingsmaterialen. Het boekje is geschreven voor een breed publiek. Het boekje gaat in eerste instantie in op onderwerpen als: (1) wanneer is een materiaal composteerbaar en hoe is dat te zien, (2) milieubelasting van composteerbare materialen en (3) de wet en regelgeving rondom composteerbare producten. Vervolgens wordt meer materiaal technisch aandacht besteed aan de nieuwe composteerbare materialen die geschikt zijn om in te zetten als materiaal voor voedselverpakkingen. Daarbij wordt per materiaal ingegaan op specifieke aspecten wat betreft de herkomst, verwerking en beschikbaarheid. Tevens zal wordt ingegaan op specifieke eigenschappen en huidige toepassingsgebieden in het algemeen en als verpakkingsmateriaal in het bijzonder.

The aquatic biodegradability of cellulose and cellulose acetate with degrees of substitution (d.s.) in the range of 1.5 to 3.0, was compared with the mineralization under laboratory controlled composting conditions. In line with previous observations, it was found that cellulose acetates with d.s. ≤ 2.5 were readily mineralized to CO2 in the controlled composting test. The degradation rate was clearly affected by the degree of substitution (d.s. 1.5 > d.s. 2.5 > d.s. 3.0). Surprisingly, however, biodegradation of cellulose acetate materials was not observed in the aquatic Sturm test. Modifications of the pH and the inoculum source in an attempt to improve the activity of fungi and actinomycetes in the aquatic environment, did not increase CO2-evolution. It is concluded that the relevance of modified Sturm tests is limited for predicting complete biodegradation of polymeric materials during biological waste processing. For evaluation of the compostability of polymeric products or packaging materials, more relevant laboratory controlled composting tests should be used.