The European position of Dutch plant communities

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African armyworm outbreaks : why do they occur after drought?

The African armyworm, Spodoptera exempta (Walker) (Lepidoptera; Noctuidae), feeds almost exclusively on plants of the families Gramineae and Cyperaceae. It is a severe pest of crops, including maize, sorghum and millet, especially on the eastern side of the African continent where a marked seasonal occurrence of outbreaks coincides with the rains. First outbreaks of a season can arise soon after the start of the short rains (October-November) in the so-called primary outbreak areas, which are located in the zone separating the lower desert area to the east from the highlands to the west in Kenya and Tanzania. Adults from these primary outbreaks migrate downwind on the prevailing easterly winds to give rise to subsequent generations further west in secondary outbreak areas. The outbreak season subsequently ends during the long dry season. No further outbreaks are reported, and densities remain very low, until the start of the following short rainy season. Current control aims to destroy, with insecticides, any outbreaks that are critical in terms of their potential to generate upsurges in following generations. Many primary outbreaks are critical in this sense.Outbreak development of the African armyworm is known to vary greatly between years in eastern Africa: in some years hardly any outbreaks are reported while in others severe infestations occur over very large areas. Drought (below average precipitation) in particular, has often been associated with the most severe outbreak seasons. As outbreaks usually seem to develop on plants which are free of drought stress but that are growing on soils that have previously been subjected to severe drought for a considerable time, the existence of a delayed indirect effect of drought on outbreak development of the African armyworm is postulated. It is hypothesized that:Periods of more severe drought encourage the occurrence of more severe outbreaks by stimulating the mineralization process in the soil when it is remoistened by rainfall as the drought breaks. This results in higher soil nitrate levels and, consequently, higher nitrogen levels in host plants of the African armyworm, thus increasing larval developmental rate and survival (especially of very young larvae) as well as the fecundity of subsequent adults.This hypothesis is based on the knowledge that the decomposition of organic material by bacteria in a soil after wetting is correlated with the duration and temperature of the drying period to which the soil has been exposed (the socalled 'Birch-effect'), and that higher nitrogen contents in host plants have often been observed to increase herbivore fitness. The aim of the present study has been to test this hypothesis.</p

Monitoring of climate variables in semi-closed greenhouses

Growers and Dutch government have concluded a covenant in which they express the ambition to reduce the carbon footprint of greenhouse production in order to improve the energy neutrality of newly built greenhouses. Conditioned cultivation in (semi-)closed greenhouses is seen as one of the instruments to reach this goal. It is appointed in the covenant to arrive in 2011 at 700 ha and in 2020 at 2,500 ha semi-closed greenhouses. This paper describes the instruments used to monitor the results of conditioned cultivation in eight semi-closed greenhouses in practice. It addresses the monitoring process, the installations involved and highlights some of the measured data

Kartering terrestrische Natura 2000 habitattypen; Botshol 2009

Momenteel worden voor de Nederlandse Natura 2000 gebieden beheerplannen opgesteld. Voor het formuleren van richtlijnen en maatregelen, alsmede om de ontwikkelingen rond de habitattypen en doelsoorten in de toekomst te kunnen evalueren, is het noodzakelijk om de uitgangssituatie ten aanzien van de habitattypen en doelsoorten goed te beschrijven. Ook de terrestrische vegetatie wordt door de grootste eigenaar in het gebied, de Vereniging Natuurmonumenten, met regelmaat beschreven, maar een eerdere analyse leerde dat de hiervoor gebruikte typologie niet eenduidig valt te vertalen naar Natura 2000 habitattypen. Daarom is in juni en juli 2009 een kartering van de terrestrische habitattypen uitgevoerd. De resultaten van deze kartering worden in dit rapport beschreven

Sensators: active multisensory tangible user interfaces

Although Tangible User Interfaces are considered an intuitive means of human-computer interaction, they oftentimes lack the option to provide active feedback. We developed ‘Sensators’: generic shaped active tangibles to be used on a multi-touch table. Sensators can represent digital information by means of ‘Sensicons’: multimodal messages consisting of visual, auditory, and vibro- tactile cues. In our demonstration, we will present Sensators as suitable tools for research on multimodal perception in different tangible HCI tasks

Effectiveness of alcohol prevention interventions based on the principles of social marketing:A systematic review

Background Alcohol education aims to increase knowledge on the harm related to alcohol, and to change attitudes and drinking behaviour. However, little (lasting) evidence has been found for alcohol education, in changing alcohol-related attitudes and behaviour. Social marketing uses marketing techniques to achieve a social or healthy goal, and can be used in alcohol education. Social marketing consists of eight principles: customer orientation, insight, segmentation, behavioural goals, exchange, competition, methods mix, and is theory based. This review investigates the application of social marketing in alcohol prevention interventions, and whether application of social marketing influences alcohol-related attitudes or behaviour. Method A literature search was conducted in PubMed, PsychInfo, Cochrane and Scopus. Inclusion criteria were that original papers had to describe the effects of an alcohol prevention intervention developed according to one or more principles of social marketing. No limits were set on the age of the participants or on the kind of alcohol prevention intervention. The abstracts of the 274 retrieved studies were reviewed and the full texts of potentially relevant studies were screened. Results Six studies met the inclusion criteria and were included in this review. These six studies showed associations for the application of social marketing techniques on alcohol-related attitudes or behaviour; one study relates to participation in a drinking event, four to alcohol drinking behaviour, two to driving a car while under the influence of alcohol, two to recognition of campaign messages or campaign logo, and one to awareness of the campaign. However, no associations were also found. In addition, the studies had several limitations related to a control group, response rate and study methodology. Conclusion Based on this review, the effect of applying the principles of social marketing in alcohol prevention in changing alcohol-related attitudes or behaviour could not be assessed. More research, with a good quality methodology, like using a randomized control trial and measuring short, medium, and long-term effects, is required on this topic. Policy implications are discussed. Keywords: Alcohol, Prevention, Effectiveness, Social marketing, Interventio

Experimental and simulation study on heat transfer in fluidized beds with heat production: An integrated DIA/PIV/IR technique and CFD-DEM

As a result of highly exothermic reactions taking place in gas-phase olefin polymerization fluidized bed reactors, difficulties concerning the heat management play an important role in the optimization of these reactors. To get a better understanding of the particle temperature distribution in fluidized beds, a high speed infrared (IR) camera and a visual camera have been coupled to obtain the hydrodynamics and thermal aspects of a pseudo-2D fluidized bed (1), as shown in figure 1. The hydrodynamics are characterized by digital image analysis and particle image velocimetry (DIA/PIV) and the heat properties by IR. The experimental data is used to validate an in-house developed computational fluid dynamics and discrete element model (CFD-DEM). In order to mimic the heat effect due to the exothermic polymerization reaction in the pseudo-2D fluidized bed reactor, a model system was used. In this model system, heat is released in zeolite 13X particles (1.8~2.0 mm) due the adsorption of CO­2. Characteristics of the adsorption kinetics, isotherm and reaction enthalpy have been achieved by performing Thermogravimetric Analysis (TGA) and Simultaneous Thermal Analysis (STA). By feeding gas mixtures of CO­2 and N2 uniformly to the reactor, the rate of adsorption can be controlled in order to obtain a pseudo-steady state of heat production in the bed. The combined technique provides insightful information on the particle temperature distribution for different CO2 concentrations, bed aspect ratios and background superficial velocities. Furthermore, the comparison of the spatial and temporal distribution of the particle temperature distribution in fluidized beds with the simulation results of CFD-DEM provides qualitative and quantitative validation of the CFD-DEM, in particular concerning the thermal aspects. Please click Additional Files below to see the full abstract

Gunstige referentiewaarden voor oppervlakte en verspreidingsgebied van Natura 2000-habitattypen in Nederland

Dit rapport geeft een overzicht van de gunstige referentiewaarden van area (oppervlakte in km2) en range (oppervlakte verspreidingsgebied incl. opvulling in 10 x 10 km-hokken) voor alle 52 habitattypen in Nederland. Deze FRA (Favourable Reference Area) en FRR (Favourable Reference Range) zijn nodig om de staat van instandhouding van habitattypen volgens artikel 17 van de Habitatrichtlijn vast te stellen. Bijna 25% van de habitattypen vereist uitbreiding van verspreidingsgebied voor een gunstige staat van instandhouding. Ruim 20% van de habitattypen vereisen zowel een uitbreiding van oppervlakte als van verspreidingsgebied voor een gunstige staat van instandhouding. Daarnaast wordt aangegeven hoe de gunstige referentiewaarden behouden of bereikt kunnen worden en wat de mogelijke invloed van klimaatverandering is. Om de trend van area te beoordelen, zijn in bijlagen schattingen gemaakt van historische oppervlakten van habitattypen rond 1950 voor heide-, stuifzand-, hoogveen- en graslandtypen

Urgent bedreigde typische soorten en vegetatietypen van Natura 2000-habitattypen

Dit rapport is de weerslag van een onderzoek naar de urgent bedreigde en potentieel urgent bedreigde typische soorten en de urgent bedreigde en potentieel urgent bedreigde vegetatietypen van de habitattypen van de Natura 2000-gebieden. In totaal zijn 67 typische soorten als Urgent Bedreigd gecategoriseerd; nog eens 26 soorten zijn gecategoriseerd als Potentieel Urgent Bedreigd. Voor de vegetatietypen geldt dat er 15 (sub)associaties Urgent bedreigd zijn. Op een bijbehorende cdrom wordt voor al deze soorten en vegetaties de huidige verspreiding gegeven, of herstel binnen of buiten Natura 2000 zou moeten plaatsvinden, wat de knelpunten hierbij zijn en waar de beste herstellocaties gelegen zijn

Internal versus external tocodynamometry during induced or augmented labour

Background Uterine contractions can be registered by external tocodynamometry (ET) or, after rupture of the membranes, by internal tocodynamometry (IT). Monitoring of the frequency of contractions is important especially when intravenous oxytocin is used as excessive uterine activity (hyperstimulation or tachysystole) can cause fetal distress. During induction of labour as well as during augmentation with intravenous oxytocin, some clinicians choose to monitor frequency and strength of contractions with IT rather than with ET as an intrauterine pressure catheter measures intrauterine activity more accurately than an extra-abdominal tocodynamometry device. However, insertion of an intrauterine catheter has higher costs and also potential risks for mother and child. Objectives To assess the effectiveness of IT compared with using ET when intravenous oxytocin is used for induction or augmentation of labour. Search methods We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 April 2012) and PubMed (1966 to 7 March 2012). Selection criteria We included all published randomised controlled trials with data from women in whom IT was compared with ET in induced or augmented labour with oxytocin. We excluded trials that employed quasi-randomised methods of treatment allocation. We found no unpublished or ongoing studies on this subject. Data collection and analysis Two review authors independently assessed trial eligibility and risk of bias, and independently extracted data. Data were checked for accuracy. Where necessary, we contacted study authors for additional information. Main results Three studies involving a total of 1945 women were included. Overall, risk of bias across the three trials was mixed. No serious complications were reported in the trials and no neonatal or maternal deaths occurred. The neonatal outcome was not statistically different between groups: Apgar score less than seven at five minutes (RR 1.78, 95% CI 0.83 to 3.83; three studies, n = 1945); umbilical artery pH less than 7.15 (RR 1.31, 95% CI 0.95 to 1.79; one study, n = 1456); umbilical artery pH less than 7.16 (RR 1.23, 95% CI 0.39 to 3.92; one study, n = 239); admission to the neonatal intensive care unit (RR 0.34, 95% CI 0.07 to 1.67; two studies, n = 489); and more than 48 hours hospitalisation (RR 0.92, 95% CI 0.71 to 1.20; one study, n = 1456). The pooled risk for instrumental delivery (including caesarean section, ventouse and forceps extraction) was not statistically significantly different (RR 1.05, 95% CI 0.91 to 1.21; three studies, n = 1945). Hyperstimulation was reported in two studies (n = 489), but there was no statistically significant difference between groups (RR 1.21, 95% CI 0.78 to 1.88). Authors' conclusions This review found no differences between the two types of monitoring (internal or external tocodynamometry) for any of the maternal or neonatal outcomes. Given that this review is based on three studies (N = 1945 women) of moderate quality, there is insufficient evidence to recommend the use of one form of tocodynamometry over another for women where intravenous oxytocin was administered for induction or augmentation of labou