La caratterizzazione endofenotipica del rimuginio

Rumination, defined as the tendency to think about the negative affect evoked by stressful events, has been identified as potentially playing a role in the development of cardiovascular diseases. Specifically, recent studies suggest that ruminative thoughts might be mediators of the prolonged physiological effects of stress. The main goal of this research was to study the effect of rumination, evoked in the laboratory, during the subsequent 24 hours. As rumination has been associated with the activity of several physiological systems, including the cardiovascular, endocrine, and immune system, we also aimed at studying the process from a psychoneuroendocrine point of view. Levels of anxiety, depression, anger, hostility, and trait rumination were assessed by the use of validated questionnaires. Impedance cardiography-derived measures, skin conductance, respiration, and beat-to-beat blood pressure (BP) were monitored continuously in 60 subjects during baseline, the Anger Recall Inteview, a reading task and two recovery periods. Half of the sample was randomly assigned to a distracter condition after the Anger Recall Inteview. Cortisol, plasma concentrations of epinephrine, norepinephrine, and inflammatory biomarkers (CRP, sICAM-1) were also obtained at baseline and at the end of the session. Then, all subjects were asked to wear an ambulatory BP monitor for 24 hours. Results show that the distracter was effective in stopping rumination in the laboratory but did not have a long-lasting effect in the subsequent 24 hours. Rumination was associated with prolonged sympathetic activity, vagal withdrawal, cortisol secrection, pro-inflammatory reaction and mood impairment compared to the reading task. After controlling for age and body mass index, rumination also proved to be a strong predictor of daily moods, and ambulatory HR and BP. Personality traits did not have an effect in determining the frequency or duration of daily rumination. Findings suggest that perseverative cognition can prolong stress- related affective and physiological activation and might act directly on somatic disease via the cardiovascular, immune, endocrine, and neurovisceral systems.

Morphological and physiological responses of apple trees under photoselective colored nets

In recent years and thanks to innovative technological advances in supplemental lighting sources and photo-selective filters, light quality manipulation (i.e. spectral composition of sunlight) have demonstrated positive effects on plant performance in ornamentals and vegetable crops. However, this aspect has been much less studied in fruit trees due to the difficulty of conditioning the light environment of orchards. The aim of the present PhD research was to study the use of different colored nets with selective light transmission in the blue (400 – 500 nm), red (600 – 700 nm) and near infrared (700 – 1100 nm) wavelengths as a tool to the light quality management and its morphological and physiological effects in field-grown apple trees. Chapter I provides a review the current status on physiological and technological advances on light quality management in fruit trees. Chapter II shows the main effect of colored nets on morpho-anatomical (stomata density, mesophyll structure and leaf mass area index) characteristics in apple leaves. Chapter III provides an analysis about the effect of micro-environmental conditions under colored nets on leaf stomatal conductance and leaf photosynthetic capacity. Chapter IV describes a study approach to evaluate the impact of colored nets on fruit growth potential in apples. Summing up results obtained in the present PhD dissertation clearly demonstrate that light quality management through photo-selective colored nets presents an interesting potential for the manipulation of plant morphological and physiological traits in apple trees. Cover orchards with colored nets might be and alternative technology to address many of the most important challenges of modern fruit growing, such as: the need for the efficient use of natural resources (water, soil and nutrients) the reduction of environmental impacts and the mitigation of possible negative effects of global climate change.