Test van 2 middelen voor voorbehandeling van biologische zomerbloemen

Bij 10 soorten zomerbloemen is het effect van voorbehandeling met middelen, die bruikbaar zouden kunnen zijn voor telers van biologische bloemen onderzocht. De bloemen kregen een transportsimulatie van 5 dagen

Maximum PV-penetration in low-voltage cable networks

As a consequence of the increasing amount of PV-systems connected to the LV-network the question arises whether these networks are able to cope with large amounts of PV. In this paper it is investigated whether problems have to be expected in typical LV networks in the Netherlands. It is shown that exceeding of the regulatory voltage levels is the first limiting factor for integration of PV, followed by overloading of components. In most parts of the network no problems will arise as a consequence of PV, as it is not possible to place enough PV panels to cause problems. Areas with increased risk can be identified on forehand

A multidisciplinary approach to schistosomiasis control in Northern Cameroon : with special reference to the role of fish in snail control

Wetensch. publicati

Snail control by fish: an explanation for its failure

Systematic studies on the performance of fish as snail eaters in waterbodies are rare. Here, trials with a promising African cichlid (Astatoreochromis alluaudi) revealed that the fish were only successful at reducing snail populations if there was nothing better to eat - and this is hardly the case. The fish need solid jaws to crush the snails but do not develop such jaws if they can find other, preferables foods. The prospects for this form of control are also discussed in the broader context

On-line acquisition of plant related and environmental parameters (plant monitoring) in gerbera: determining plant responses

For on-line plant monitoring equipment to be functional in commercial glasshouse horticulture, relations between sensor readings and plant responses on both the short (days) and long term (weeks) are required. For this reason, systems were installed to monitor rockwool grown gerbera plants on a minute-to-minute basis from July 2002 until April 2003. Data collected included, amongst others, crop transpiration from lysimeter data (2 m2), canopy temperature using infrared sensors, rockwool water content, and greenhouse climatic parameters, such as global radiation and temperature. By combining data from lysimeter and water content, changes in crop fresh weight could be calculated on a daily basis. Both transpiration and daily fresh weight production were better related to light integral as measured inside the greenhouse, than outside the greenhouse. The contribution of heating pipes underneath the canopy to transpiration could be estimated with the system. From the relation between daily FW production and previous day light integral, a light use efficiency of ca. 10-g FW/MJ solar radiation as measured inside the greenhouse was calculated. Water use efficiency was on average 25 g FW/L. A 3-4 day drying cycle did not affect flower production. The results underline the importance of knowledge on the adaptation and tolerance of crops to stressful conditions, in order to be able to use plant monitoring under grower conditions effectively

Offshore Wind Energy Conversion System Connected to the Electric Grid: Modeling and Simulation

This paper is on modeling and simulation for an offshore wind system equipped with a semi-submersible floating platform, a wind turbine, a permanent magnet synchronous generator, a multiple point clamped four level or five level full-power converter, a submarine cable and a second order filter. The drive train is modeled by three mass model considering the resistant stiffness torque, structure and tower in deep water due to the moving surface elevation. The system control uses PWM by space vector modulation associated with sliding mode and proportional integral controllers. The electric energy is injected into the electric grid either by an alternated current link or by a direct current link. The model is intend to be a useful tool for unveil the behavior and performance of the offshore wind system, especially for the multiple point clamped full-power converter, under normal operation or under malfunctions

Mosquitoes and malaria transmission in irrigated rice-fields in the Benoue valley of northern Cameroon

International audienc

Catalytic Dehydrogenation of Amine-Boranes using Geminal Phosphino-Boranes

The reaction of the intramolecular frustrated Lewis pair (FLP) tBu2PCH2BPh2 with the amine-boranes NH3·BH3 and Me2NH·BH3 leads to the formation of the corresponding FLP-H2 adducts as well as novel five-membered heterocycles that result from capturing the in situ formed amino-borane by a second equivalent of FLP. The sterically more demanding tBu2PCH2BMes2 does not form such a five-membered heterocycle when reacted with Me2NH·BH3 and its H2 adduct liberates dihydrogen at elevated temperatures, promoting the metal-free catalytic dehydrogenation of amine-boranes.Peer reviewe

Human Papillomavirus and Oropharyngeal Squamous Cell Carcinoma: A Case-Control Study regarding Tobacco and Alcohol Consumption

We aimed to determine the role of HPV in the pathogenesis and outcome of oropharyngeal squamous cell carcinoma (OSCC) in lifelong nonsmoking and nondrinking patients. A case-case analysis was performed to compare the presence of HPV-DNA in tumor cells of 16 nonsmoking and nondrinking with 16 matched smoking and drinking patients (matching criteria: age at incidence, gender, tumor sublocation, tumor stage). HPV was detected using 2 PCR tests, FISH analysis, and p16INK4A immunostaining. Nonsmoking and nondrinking patients had more HPV-positive tumors than smoking and drinking patients (n = 12; 75% versus n = 2; 13%; P < 0.001). All HPV-positive tumors showed p16INK4A overexpression, and 1 HPV-negative tumor had p16INK4A overexpression, (P < 0.001). Overall survival and disease-specific survival were higher for HPV-positive compared to HPV-negative cases (P = 0.027, P = 0.039, resp.). In conclusion, HPV is strongly associated with OSCC of nonsmoking and nondrinking patients. Specific diagnostic and therapeutic actions should be considered for these patients to achieve a better prognosis