Aaltjes in de biologische akkerbouw en vollegrondsgroenteteelt

In de bodem leven vele soorten aaltjes. De schadelijke plantparasitaire aaltjes kunnen op verschillende gewassen of waardplanten overleven. Ook op biologische percelen ontstaat soms schade door hoge populaties aaltjes. In dit BioKennisbericht een overzicht van de meest voorkomende schadelijke aaltjes en maatregelen die schade kunnen beperken. Ruime vruchtwisseling is één van de preventieve methoden om schade door aaltjes en andere bodemgebonden plagen te voorkomen

Rendabele biologische komkommerteelt

De biologische komkommerteelt is in meerdere opzichten een lastige teelt. De kwetsbaarheid van het gewas is groot, zowel vanuit de bodem als vanuit de lucht liggen belagers op de loer. Glastuinders zijn daarom op zoek naar een teeltsysteem dat past bij de grondteelt en voldoende productie plus kwaliteit oplevert. Om glastuinders meer zekerheid te bieden zijn zaadbedrijven en onderzoekers op zoek naar geschikte onderstammen en rassen. Op de bedrijven zelf wordt veel geëxperimenteerd met teeltsystemen, van traditioneel tot hoge draad en wat ertussenin valt

Music production and its role in coalition signaling during foraging contexts in a hunter-gatherer society

Music is a cultural activity universally present in all human societies. Several hypotheses have been formulated to understand the possible origins of music and the reasons for its emergence. Here, we test two hypotheses: (1) the coalition signaling hypothesis which posits that music could have emerged as a tool to signal cooperative intent and signal strength of alliances and (2) music as a strategy to deter potential predators. In addition, we further explore the link between tactile cues and the propensity of mothers to sing toward infants. For this, we investigated the singing behaviors of hunter-gatherer mothers during daily foraging trips among the Mbendjele BaYaka in the Republic of the Congo. Although singing is a significant component of their daily activities, such as when walking in the forest or collecting food sources, studies on human music production in hunter-gatherer societies are mostly conducted during their ritual ceremonies. In this study, we collected foraging and singing behavioral data of mothers by using focal follows of five BaYaka women during their foraging trips in the forest. In accordance with our predictions for the coalition signaling hypothesis, women were more likely to sing when present in large groups, especially when group members were less familiar. However, predictions of the predation deterrence hypothesis were not supported as the interaction between group size and distance from the village did not have a significant effect on the likelihood of singing. The latter may be due to limited variation in predation risk in the foraging areas, because of the intense bush meat trade, and hence, future studies should include foraging areas with higher densities of wild animals. Lastly, we found that mothers were more likely to sing when they were carrying infants compared to when infants were close, but carried by others, supporting the prediction that touch plays an important prerequisite role in musical interaction between the mother and child. Our study provides important insight into the role of music as a tool in displaying the intent between or within groups to strengthen potentially conflict-free alliances during joint foraging activities

The role of the school in inculcating citizenship values in South Africa: Theoretical and international comparative perspectives

In view of the serious moral decay in South African society, this article reports on our research regarding the role of the school in the inculcation of citizenship values (as part of the brief of South African education). We regard a set of citizenship values consonant with a democratic dispensation to be a core component of a moral order essential for South Africa. Using a combination of interpretive-constructivist and comparative approaches, we examine and evaluate the experiences of other post-conflict societies in using education to inculcate citizenship values. We conclude that schools can be successful with respect to the inculcation of citizenship values, provided that the curriculum itself does not discriminate against any group or category of people. Desegregation can only be beneficial in the absence of negative depiction (including criminalisation) or the unequal treatment of any particular societal grouping. Our research suggests that active citizenship education is needed in schools. For this reason, we contend that teacher education has to form an integral part of a moral revival project. Lastly, we highlight the importance of finding democratically agreed-upon ways to continually engage with parents, legal caregivers and other stakeholders and role-players before and during the execution of any such project. Keywords: citizenship; citizenship education; citizenship values; democracy; globalisation; political reform; post-conflict societies;  school as social institution; social justice; value systems&nbsp

Comparison of Longitudinal Membrane Function in Peritoneal Dialysis Patients According to Dialysis Fluid Biocompatibility

Introduction: Preservation of peritoneal function is essential in long-term peritoneal dialysis. Biocompatible dialysis solutions might prevent or postpone the membrane alteration resulting in ultrafiltration failure and consecutive morbidity and mortality. Methods: We conducted an observational cohort study in which we made a longitudinal comparison between the course of peritoneal solute and fluid transport during treatment with conventional and biocompatible solutions. Therefore, prospectively collected peritoneal transport data from the yearly standard peritoneal permeability analysis were analyzed in 251 incident patients treated between 1994 and censoring in 2016. Fluid transport included small pore and free water transport. Solute transport was assessed by creatinine mass transfer area coefficient and glucose absorption. Linear mixed models including change point analyses were performed. Interaction with peritonitis was examined. Results: One hundred thirty-five patients received conventional and 116 biocompatible solutions. Sixtyseven percent (conventional) and 64% (biocompatible) of these underwent minimally three transport measurements. Initially, biocompatible fluids showed higher small solute transport and lower ultrafiltration than conventional fluids up to 3 years. Thereafter, conventional fluids showed an increase in small solute transport (+2.7 ml/min per year; 95% confidence interval [CI]: 0.9 to 4.5) and a decrease of free water transport (-28.0 ml/min per year; 95% CI: -60.4 to 4.4). These were minor or absent in biocompatible treatment. Peritonitis induced a decrease of transcapillary ultrafiltration after 2 years on dialysis with conventional solutions (-291 ml/min per year; 95% CI: -550 to -32) while this was absent in biocompatible treatment. Conclusion: Despite a higher initial solute transport with biocompatible solutions, these have less influence on functional long-term peritoneal alterations than conventional solutions. (C) 2020 International Society of Nephrology. Published by Elsevier Inc

Use of controlled atmospheres to enhance essential oil fumigant toxicity against Western Flower Thrips, Frankliniella occidentalis

The fumigant toxicity of selected essential oils was assessed against the Western Flower Thrips, Frankliniella occidentalis. Adult females and larvae were exposed to combinations of essential oil doses and increased carbon dioxide and decreased oxygen levels. Application of such combinations were found to significantly increase the fumigant toxicity against thrips. An increase in exposure time also led to an increase in mortalities in both essential oil alone and combined treatments. These results indicate that by combining applications of the essential oils with e.g. moderately increased carbon dioxide levels (2 to 10%), it may be possible to achieve toxicity levels similar to those of standard chemical fumigant