A method to detect baseline emission and plant damage induced volatile emission in a greenhouse

The objective of this research was to ascertain if 1) baseline emission and 2) damage induced emission of volatile plant substances could be detected under greenhouse conditions. A laboratory method was validated for analysing the air in a semi-closed greenhouse with 44 m2 floor area. This greenhouse, with a volume of 270 m3, was climate controlled and light was supplied with assimilation lamps. Sixty tomato plants (Lycopersicon esculentum Mill cv. Moneymaker) were grown in this greenhouse. These plants were artificially damaged on a weekly interval by stroking the stems. Continuous flow pumps were used to purge the air surrounding the plants through tubes containing an adsorbent. This sampling step was performed before and directly after damage of the plants. After sampling, the tubes were transferred to the lab for analysis. The analysis of volatile compounds was performed using a high-throughput gas chromatography-mass spectrometry system. The method enabled the detection of baseline level emission and the emission of volatiles released after artificially damaging the tomato plants during a 6 weeks growing period. Most dominant compounds for baseline emission were the monoterpenes ß-phellandrene, 2-carene, limonene, ¿-phellandrene and ¿-pinene. Directly after damage, these compounds showed an increase of up to 100 times compared to baseline level emission. With these results, we prove that it is possible to detect baseline- and plant damage induced volatile emission in a greenhouse. This area of research is promising but more research needs to be done to determine whether it is possible to detect plant damage due to pests and pathogens using volatile sensing

Probleemgestuurd onderwijs

Sinds januari 1998 is Probleemgestuurd Onderwijs, hierna PGO te noemen, ingevoerd in de propedeuse van bestuurskunde. Maar wat is nu precies PGO en wat zijn de verschillen met regulier onderwijs? Een verslag en enkele kritische noten na een half jaar PGO in het bestuurskunde curriculum

Insight Into Molecular Determinants of T3 vs T4 Recognition From Mutations in Thyroid Hormone Receptor α and β.

CONTEXT: The two major forms of circulating thyroid hormones (THs) are T3 and T4. T3 is regarded as the biologically active hormone because it binds to TH receptors (TRs) with greater affinity than T4. However, it is currently unclear what structural mechanisms underlie this difference in affinity. OBJECTIVE: Prompted by the identification of a novel M256T mutation in a resistance to TH (RTH)α patient, we investigated Met256 in TRα1 and the corresponding residue (Met310) in TRβ1, residues previously predicted by crystallographic studies in discrimination of T3 vs T4. METHODS: Clinical characterization of the RTHα patient and molecular studies (in silico protein modeling, radioligand binding, transactivation, and receptor-cofactor studies) were performed. RESULTS: Structural modeling of the TRα1-M256T mutant showed that distortion of the hydrophobic niche to accommodate the outer ring of ligand was more pronounced for T3 than T4, suggesting that this substitution has little impact on the affinity for T4. In agreement with the model, TRα1-M256T selectively reduced the affinity for T3. Also, unlike other naturally occurring TRα mutations, TRα1-M256T had a differential impact on T3- vs T4-dependent transcriptional activation. TRα1-M256A and TRβ1-M310T mutants exhibited similar discordance for T3 vs T4. CONCLUSIONS: Met256-TRα1/Met310-TRβ1 strongly potentiates the affinity of TRs for T3, thereby largely determining that T3 is the bioactive hormone rather than T4. These observations provide insight into the molecular basis for underlying the different affinity of TRs for T3 vs T4, delineating a fundamental principle of TH signaling

Fruit Detectability Analysis for Different Camera Positions in Sweet-Pepper

For robotic harvesting of sweet-pepper fruits in greenhouses a sensor system is required to detect and localize the fruits on the plants. Due to the complex structure of the plant, most fruits are (partially) occluded when an image is taken from one viewpoint only. In this research the effect of multiple camera positions and viewing angles on fruit visibility and detectability was investigated. A recording device was built which allowed to place the camera under different azimuth and zenith angles and to move the camera horizontally along the crop row. Fourteen camera positions were chosen and the fruit visibility in the recorded images was manually determined for each position. For images taken from one position only with the criterion of maximum 50% occlusion per fruit, the fruit detectability (FD) was in no case higher than 69%. The best single positions were the front views and looking with a zenith angle of 60° upwards. The FD increased when a combination was made of multiple viewpoint positions. With a combination of five favourite positions the maximum FD was 90%

Het onderzoek van ir. van Hoffen naar de Bennekomse boerensamenleving

Het enquête-materiaal, door Ir van Hoffen nagelaten, biedt aan de niet-kenner van agrarisch Bennekom de mogelijkheid enkele sociologische opmerkingen te maken over de Bennekomse boer

Stability and change in maternal parenting profiles across infancy and toddlerhood

During infancy and toddlerhood, parents show large individual differences in the extent to which they are able to tailor their parenting behaviors to their children's swiftly changing developmental needs. The first aim of our study was, therefore, to distinguish parenting profiles at three time points during infancy and toddlerhood (i.e., 5, 10, and 36 months) based on mothers' supportive presence, structure and limit-setting, and quality of instruction, as well as to examine the stability of profile structure and profile membership across time. The second aim was to examine how profile membership and profile transitions at each time point are associated with relevant parental, contextual, and child-specific factors. Data from 244 Dutch mother-child dyads were collected at three waves: when children were approximately 5 months ( n = 203), 10 months ( n = 181), and 3 years of age ( n = 178). We found three types of parenting profiles at each wave: a competent profile, a sufficient profile, and a maladaptive profile. Only the competent parenting profile was found to have a stable structure across all three waves. In general, profile membership was least stable for the maladaptive profile. Results also showed that maternal agreeableness and a higher educational level increased the likelihood to exhibit a more competent parenting profile. Our findings advance our understanding of how parenting profiles might change due to children's swiftly changing needs and inform efforts to tailor parenting interventions to individual parents. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

The reliability of the patellotrochlear index on magnetic resonance imaging for measuring patellofemoral height

Background: The purpose of this study was to determine the inter-and intra-observer reliability of the patellotrochlear index (PTI) on magnetic resonance images (MRI) in patients with patellofemoral pain. The correlation between the PTI measured on MRI and the modified Insall-Salvati (MIS) ratio measured on radiographs was also assessed. Methods: The PTI was assessed on MRI images and the MIS ratio on radiographs of 66 knees of 62 patients. Assessment was performed by two orthopaedic surgeons, one orthopaedic surgery registrar, two radiologists and one radiology registrar. Correlation coefficients, standard errors of measurement and limits of agreement were calculated for the PTI. To assess the association between the PTI and the MIS ratio, the Pearson's correlation coefficient was calculated. Results: The PTI showed good interobserver reliability (intraclass correlation coefficient (ICC) 0.79; 95% confidence interval (CI) 0.73-0.85) and excellent intra-observer reliability (ICC 0.90; 95% CI 0.89-0.91). The standard error of measurement was 0.05 and limits of agreement with the mean +/- 0.09. A very weak and not significant correlation was found between the PTI and the MIS (r = 0.02; P = 0.77). Conclusions: The PTI showed good interobserver reliability and excellent intra-observer reliability. In order to conclude which measurement method of assessing patellar height is truly the most reliable, future studies should investigate agreement parameters (standard error of measurement, limits of agreement) besides solely correlation coefficients. We found a very weak correlation between the PTI and the MIS which suggests that at least one index has poor validity. Future validity studies on indices to assess patellar height are necessary. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)