Toepassing van weefselkweek en embryogenese bij vermeerdering en veredeling van tulp

In dit rapport worden de resultaten beschreven van twee projecten waarin weekfselkweekmethoden voor vermeerderding en veredeling van tulp zijn onderzocht. Vermeerdering van tulp op het veld gaat erg langzaam waardoor het lang duurt voordat nieuwe cultivars op de markt kunnen worden gebracht. Vermeerdering m.b.v. weefselkweek kan dit aanzienlijk versnellen. Het protocol dat bij aanvang van de twee projecten beschikbaar was, is aanzienlijk verbeterd. In het eerste project werd nagegaan of somatische embryogenese (vorming van embryo's uit niet-geslachtscellen) toepasbaar is voor een sneller vermeerderingssysteem van tulp. Het tweede project draaide om het verbeteren van de vermeedering van tulp in vitro, uitgaande van scheutvorming op bloemstengelplakje

Afwijkingen in bloeibare Zantedeschiaknollen vanuit weefselkweek

Voor de teelt van Zantedeschia wordt veel gebruik gemaakt van plantmateriaal dat is vermeerderd via weefselkweek. Sinds de introductie van planten vermeerderd via weefselkweek zijn in toenemende mate afwijkingen in plantmateriaal waargenomen die worden toegeschreven aan de weefselkweekvermeerdering. Het gaat daarbij om afwijkingen zoals bossigheid, bont en extreem smal blad en bladverruwing. In dit onderzoek is het effect van een aantal behandelingen in weefselkweek op afwijkingen onderzocht

Neural processing of social rejection: the role of schizotypal personality traits

A fear of being rejected can cause perceptions of more insecurity and stress in close relationships. Healthy individuals activate the dorsal anterior cingulate cortex (dACC) when experiencing social rejection, while those who are vulnerable to depression deactivate the dACC presumably to downregulate salience of rejection cues and minimize distress. Schizotypal individuals, characterized by unusual perceptual experiences and/or odd beliefs, are more rejection sensitive than normal. We tested the hypothesis, for the first time, that individuals with high schizotypy also have an altered dACC response to rejection stimuli. Twenty-six healthy individuals, 14 with low schizotypy (LS) and 12 with high schizotypy (HS), viewed depictions of rejection and acceptance and neutral scenes while undergoing functional MRI. Activation maps in LS and HS groups during each image type were compared using SPM5, and their relation to participant mood and subjective ratings of the images was examined. During rejection relative to neutral scenes, LS activated and HS deactivated the bilateral dACC, right superior frontal gyrus, and left ventral prefrontal cortex. Across both groups, a temporo-occipito-parieto-cerebellar network was active during rejection, and a left fronto-parietal network during acceptance, relative to neutral scenes, and the bilateral lingual gyrus during rejection relative to acceptance scenes. Our finding of dACC-dorso-ventral PFC activation in LS, but deactivation in HS individuals when perceiving social rejection scenes suggests that HS individuals attach less salience to and distance themselves from such stimuli. This may enable them to cope with their higher-than-normal sensitivity to rejection

Self-defining Memories, Scripts, and the Life Story: Narrative Identity in Personality and Psychotherapy

An integrative model of narrative identity builds on a dual memory system that draws on episodic memory and a long-term self to generate autobiographical memories. Autobiographical memories related to critical goals in a lifetime period lead to life-story memories, which in turn become self-defining memories when linked to an individual\u27s enduring concerns. Self-defining memories that share repetitive emotion-outcome sequences yield narrative scripts, abstracted templates that filter cognitive-affective processing. The life story is the individual\u27s overarching narrative that provides unity and purpose over the life course. Healthy narrative identity combines memory specificity with adaptive meaning-making to achieve insight and well-being, as demonstrated through a literature review of personality and clinical research, as well as new findings from our own research program. A clinical case study drawing on this narrative identity model is also presented with implications for treatment and research

A high implicit affiliation motive does not always make you happy: A corresponding explicit motive and corresponding behavior are further needed

Satisfaction of the implicit affiliation motive is known to be positively related to emotional well-being, whereas the frustration of the implicit affiliation motive leads to impairment of well-being. In the present research we specified two conditions that are responsible for the satisfaction and frustration of the implicit motive. Referring to research on the congruence of implicit and explicit motives, we assumed that a corresponding explicit affiliation motive leads to satisfaction of the implicit motive. Corresponding affiliation behavior constitutes the second condition. Three studies confirmed the hypothesis that both conditions must be fulfilled in order to positively connect the implicit affiliation motive to emotional well-being. Participants with high implicit and explicit affiliation motives and who additionally showed a large amount of affiliation behavior reported the lowest negative affectivity and the highest life satisfaction compared to participants who lacked one of the conditions

Mental simulation as substitute for experience

People spend a considerable amount of their time mentally simulating experiences other than the one in which they are presently engaged, as a means of distraction, coping, or preparation for the future. In this integrative review, we examine four (non-exhaustive) cases in which mentally simulating an experience serves a different function, as a substitute for the corresponding experience. In each case, mentally simulating an experience evokes similar cognitive, physiological, and/or behavioral consequences as having the corresponding experience in reality: (1) imagined experiences are attributed evidentiary value like physical evidence, (2) mental practice instantiates the same performance benefits as physical practice, (3) imagined consumption of a food reduces its actual consumption, and (4) imagined goal achievement reduces motivation for actual goal achievement. We organize these cases under a common superordinate category and discuss their different methodological approaches and explanatory accounts. Our integration yields theoretical and practical insights into when and why mentally simulating an experience serves as its substitute