359 research outputs found

    Mixed cropping systems for biological control of weeds and pests in organic oilseed crops

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    Agricultural advantages of mixed cropping are gained by biological effects like light competition, offering weed-suppressing capacities or by diversification of plant covers to break development cycles of pests. In a two-year project on mixed cropping with organic oilseed crops these effects were measured. It was found that weeds can be efficiently suppressed in organic linseed (Linum usitatissivum) in crop combinations with wheat (Triticum aestivum) or false flax (Camelina sativa). But linseed development was strictly limited. Also in organic pea production (Pisum sativum) the introduction of mixtures with the oil crop false flax led to a significant decrease of weed population. Either culture showed a balanced plant development. In winter rape (Brassica napus) hints were found that infestation by insect pests can be directly reduced in mixtures with cereals or legumes and that parasitoids of insect pests are supported

    X-irradiation of cells on glass slides has a dose doubling impact

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    Immunofluorescence detection of γH2AX foci is a widely used tool to quantify the induction and repair of DNA double-strand breaks (DSBs) induced by ionising radiation. We observed that X-irradiation of mammalian cells exposed on glass slides induced twofold higher foci numbers compared to irradiation with γ-rays. Here, we show that the excess γH2AX foci after X-irradiation are produced from secondary radiation particles generated from the irradiation of glass slides. Both 120 kV X-rays and 137Cs γ-rays induce ∼20 γH2AX foci per Gy in cells growing on thin (∼2 μm) plastic foils immersed in water. The same yield is obtained following γ-irradiation of cells growing on glass slides. However, 120 kV X-rays produce ∼40 γH2AX foci per Gy in cells growing on glass, twofold greater than obtained using cells irradiated on plastic surfaces. The same increase in γH2AX foci number is obtained if the plastic foil on which the cells are grown is irradiated on a glass slide. Thus, the physical proximity to the glass material and not morphological differences of cells growing on different surfaces accounts for the excess γH2AX foci. The increase in foci number depends on the energy and is considerably smaller for 25 kV relative to 120 kV X-rays, a finding which can be explained by known physical properties of radiation. The kinetics for the loss of foci, which is taken to represent the rate of DSB repair, as well as the Artemis dependent repair fraction, was similar following X- or γ-irradiation, demonstrating that DSBs induced by this range of treatments are repaired in an identical manner

    Improving knowledge and changing behavior towards guideline based decisions in diabetes care: a controlled intervention study of a team-based learning approach for continuous professional development of physicians.

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    Continuing Professional Development (CPD) courses should ideally improve a physician's knowledge and change their professional behavior in daily practice towards a best clinical practice reference model and guideline adherence. Interactive methods such as team-based learning and case-based learning, as compared to lectures, can impart sustainable knowledge and lead to high satisfaction among participants. We designed an interactive case-based CPD-seminar on diabetes care using a team-based learning approach to evaluate whether it leads to an improvement of short-term knowledge and changing of behavior towards guideline based decisions and how this learning approach is perceived by participants

    Predictors of Psychological Strain and Allostatic Load in Teachers: Examining the Long-Term Effects of Biopsychosocial Risk and Protective Factors Using a LASSO Regression Approach.

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    Teacher stress significantly challenges teachers' health, teaching quality, and students' motivation and achievement. Thus, it is crucial to identify factors that effectively prevent it. Using a LASSO regression approach, we examined which factors predict teachers' psychological strain and allostatic load over two years. The study included 42 teachers (28 female, Mage = 39.66, SD = 11.99) and three measurement time points: At baseline, we assessed teachers' (a) self-reports (i.e., on personality, coping styles, and psychological strain), (b) behavioral data (i.e., videotaped lessons), and (c) allostatic load (i.e., body mass index, blood pressure, and hair cortisol concentration). At 1- and 2-year follow-ups, psychological strain and allostatic load biomarkers were reassessed. Neuroticism and perceived student disruptions at baseline emerged as the most significant risk factors regarding teachers' psychological strain two years later, while a positive core self-evaluation was the most important protective factor. Perceived support from other teachers and the school administration as well as adaptive coping styles were protective factors against allostatic load after two years. The findings suggest that teachers' psychological strain and allostatic load do not primarily originate from objective classroom conditions but are attributable to teachers' idiosyncratic perception of this environment through the lens of personality and coping strategies

    Teachers' perception of aggressive student behavior through the lens of chronic worry and resignation, and its association with psychophysiological stress: An observational study.

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    Aggressive student behavior is considered a leading risk factor for teacher stress. However, teachers' coping styles may affect how they perceive and respond to aggressive student behavior. This study tests whether teachers' perceptions of aggressive student behavior mainly mirror objectively observed aggression in presence of the teacher (as coded by external observers) or whether teachers' perception of aggressive student behavior primarily reflects teachers' avoidant coping styles, such as chronic worry and resignation. Finally, we examine whether observed and teacher-perceived aggression relates to increased vital exhaustion and psychophysiological stress among teachers (i.e., higher hair cortisol concentration). In an ambulatory assessment study, we administered self-reports to 42 Swiss teachers to assess perceived student aggression, chronic worry, resignation, and vital exhaustion. Additionally, four consecutive lessons per teacher were filmed, and aggressive student behavior in presence of the teacher was coded by four trained external observers. The concentration of cortisol was assessed in hair samples. Results showed that teacher-perceived and observed aggression were moderately associated. Observed aggression was related to teacher perceptions to a much lesser extent than teachers' avoidant coping styles, that is, chronic worry and resignation. While teacher-perceived student aggression was associated with teachers' self-reported vital exhaustion, we did not find any significant association with hair-cortisol concentration. Our findings suggest that teachers perceive student aggression through the lens of their coping styles. Teachers' dysfunctional coping styles are associated with an overestimation of student aggression. Teachers' overestimation of student aggression relates to higher levels of vital exhaustion. Therefore, it is crucial to identify and change teachers' dysfunctional coping styles to prevent a vicious cycle of dysfunctional teacher-student interactions

    Associations between stress, resources, and hair cortisol concentration in teachers.

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    Challenging interactions are the main source of teacher' stress in the classroom. We investigated the association of chronic stress and characteristics of teacher-student interactions with teachers' Hair Cortisol Concentration (HCC). Forty-one teachers (27 women; Mage = 39.65 ± 12.14 years; Mlesson number = 23.15 ± 3.99 lessons per week; grade: elementary, secondary, high, and vocational school teachers) participated in the present study, with participation lasting over the length of one year. HCC was assessed from a 3 cm hair segment near the scalp. Self-reported chronic stress in the last three months was further assessed using the 'Trier Inventory for Chronic Stress' (TICS). Additionally, four consecutive, same-day lectures of each teacher were videotaped and coded offline in an event sampling procedure by trained external observers. The videos were analyzed for two stressors, i.e., classroom disruptions and total student aggression, as well as two resources, i.e., teacher-student relationship and classroom management. Overall, hair samples were collected M = 120.34 days (SD = 84.39) after the distribution of the questionnaires, and M = 67.63 days (SD = 18.40) prior to the observations. Lesson number, classroom disruptions, as well as total student aggression were all significantly positively correlated with HCC. In addition, both teacher-student relationship and classroom management were significantly negatively related to HCC. With regard to self-rated chronic stress, only the TICS subscale 'Pressure to perform' was positively related to HCC. Exploratory moderation analyses revealed that an increasingly good, observed teacher-student relationship buffered the positive association between lesson number and HCC. Our findings show significant associations between HCC and mainly objectively assessable stress, supporting HCC as a biological indicator of chronic stress. In this association, a good relationship between teachers and students acts as a buffer. While the findings underline the importance of examining objective and behavioral data for better understanding the psychobiology of stress, they also support the importance of boostering teachers' (social) resources to increase their overall resilience

    Ansatz zur ganzheitlichen Erstellung und Verarbeitung von Dienstleistungsmodellen

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    Obgleich die Notwendigkeit einer Dienstleistungsmodellierung ausreichend anerkannt ist, wird ein Fehlen einer ganzheitlichen Modellierungsmethode weiterhin bemängelt. Einen Grund für dieses Fehlen sehen die Autoren darin, dass bei der Erstellung von Dienstleistungsmodellen die Metamodellebenen oftmals nicht klar genug getrennt werden. Eine solche Trennung kann zu einer wesentlichen Verbesserung der Ergebnisse bei Forschungsbemühungen in der Domäne der Dienstleistungsmodellierung führen. Gleichzeitig impliziert eine Betrachtung von Metamodellebenen die Notwendigkeit der Interoperabilität auf der Ebene der Metametamodelle. Dieser Beitrag legt die Gründe für die Notwendigkeit einer klaren Betrachtung der Metamodellierungsebenen dar und zeigt die Möglichkeit eines Mappings auf der Ebene der Metametamodelle als elementares Gestaltungselement einer ganzheitlichen Modellierungsmethode auf

    Longitudinal Associations Between Core Self-Evaluation, Vital Exhaustion and Hair Cortisol in Teachers and the Mediating Effects of Resignation Tendency.

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    Work-related stress appears to be especially high among teachers. However, most research on teacher stress relies exclusively on teachers' self-reports. Little is known about the physiological correlates of affective stress in teachers. This longitudinal study investigates the relationship between core self-evaluation and adverse psychological and physiological stress outcomes in 42 teachers. Self-report questionnaires were used to assess core self-evaluation, vital exhaustion, and resignation tendency. The concentration of cortisol was assessed using hair samples. One year after the initial measurement, vital exhaustion and hair cortisol were assessed again. Path-analytic mediational models showed that core self-evaluation strongly predicted vital exhaustion, and resignation tendency partially mediated this relationship. However, core self-evaluation did not predict hair cortisol concentration. These findings suggest that core self-evaluation plays a crucial role in preventing vital exhaustion among teachers. A positive core self-evaluation seems beneficial for teachers' primary and secondary appraisal and an essential resource for the long-term prevention of self-reported vital exhaustion

    rapmad: Robust analysis of peptide microarray data

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    Background: Peptide microarrays offer an enormous potential as a screening tool for peptidomics experiments and have recently seen an increased field of application ranging from immunological studies to systems biology. By allowing the parallel analysis of thousands of peptides in a single run they are suitable for high-throughput settings. Since data characteristics of peptide microarrays differ from DNA oligonucleotide microarrays, computational methods need to be tailored to these specifications to allow a robust and automated data analysis. While follow-up experiments can ensure the specificity of results, sensitivity cannot be recovered in later steps. Providing sensitivity is thus a primary goal of data analysis procedures. To this end we created rapmad (Robust Alignment of Peptide MicroArray Data), a novel computational tool implemented in R. Results: We evaluated rapmad in antibody reactivity experiments for several thousand peptide spots and compared it to two existing algorithms for the analysis of peptide microarrays. rapmad displays competitive and superior behavior to existing software solutions. Particularly, it shows substantially improved sensitivity for low intensity settings without sacrificing specificity. It thereby contributes to increasing the effectiveness of high throughput screening experiments. Conclusions: rapmad allows the robust and sensitive, automated analysis of high-throughput peptide array data. The rapmad R-package as well as the data sets are available from http://www.tron-mz.de/compmed
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