The principal at risk: Stress and organizing mindfulness in the school context

Background: In recent years the role of school principals is becoming increasingly complex and responsible. Methods: This study was voluntarily attended by 419 Italian school principals who were administered the Psychological Stress Measurement (MSP), Mindfulness Organizing Scale (MOS), Polychronic-Monochronic Tendency Scale (PMTS), and the Scale of Emotions at Work (SEW). Results: The study has produced a path analysis model in which the relationships between the main predictors of principals’ work discomfort were explained. The effect of depressive anxiety on perceived discomfort (ß = 0.517) found a protective mediator in the mindfulness component that recognizes the sharing as a fundamental operational tool (ß = −0.206), while an increasing sense of effort and confusion could significantly amplify the experience of psychological discomfort associated with the exercise of school leadership (ß = 0.254). Conclusions: The model developed in this study suggests that focusing on organizing mindfulness can be a valuable guideline for interventions

Corrosion behavior of dental implants immersed into human saliva: Preliminary results of an in vitro study

Over the years, dif- ferent implant surfaces have been used to try to maximize bone to implant contact. The aim of this study was to compare levels of metallic ions and particles dissolution collected from two dif- ferent dental implants surfaces immersed into human saliva. PATIENTS AND METHODS: A total of 60 den- tal implants were tested. Group A: sanded with aluminium oxide medium grade particles and ac- id-etched; Group B: micro-sanded with calcium phosphate powders and acid-etched. Forty im- plants were immersed in 20 ml of human saliva, twenty, as a control, in sterile saline solution. ICP-MS was performed to detect any metallic ions released from dental implants at T0, on day 1 (T1), on day 3 (T2), after one week (T3), on day 14 (T4), after 3 months (T5) and after 6 months (T6). RESULTS: Dissolution of metallic particles of titanium and nickel, absent in human saliva (T0), were found after one week (T3) for Group B and after 3 months (T5) for Group A. Vanadium was already detected in small concentrations in either group after 1 day, with an exponential growth for Group B. CONCLUSIONS: Preliminary results reported signi cant values of Ti, Ni and V released by Group B, showing for the rst time statistically signi cant values of vanadium

Monitoring stimulated emission at the single photon level in one-dimensional atoms

We theoretically investigate signatures of stimulated emission at the single photon level for a two-level atom interacting with a one-dimensional light field. We consider the transient regime where the atom is initially excited, and the steady state regime where the atom is continuously driven with an external pump. The influence of pure dephasing is studied, clearly showing that these effects can be evidenced with state of the art solid state devices. We finally propose a scheme to demonstrate the stimulation of one optical transition by monitoring another one, in three-level one-dimensional atoms.Comment: 4 pages, 4 figures. Improved introduction; Comments adde

Inhibition of electromagnetically induced absorption due to excited state decoherence in Rb vapor

The explanation presented in [Taichenachev et al, Phys. Rev. A {\bf 61}, 011802 (2000)] according to which the electromagnetically induced absorption (EIA) resonances observed in degenerate two level systems are due to coherence transfer from the excited to the ground state is experimentally tested in a Hanle type experiment observing the parametric resonance on the $$ line of $^{87}$Rb. While EIA occurs in the $F=1\to F^{\prime}=2$ transition in a cell containing only $Rb$ vapor, collisions with a buffer gas ($30 torr$ of $Ne$) cause the sign reversal of this resonance as a consequence of collisional decoherence of the excited state. A theoretical model in good qualitative agreement with the experimental results is presented.Comment: 8 pages, 7 figures, submitted to Physical Review

Abelian symmetries in multi-Higgs-doublet models

N-Higgs doublet models (NHDM) are a popular framework to construct electroweak symmetry breaking mechanisms beyond the Standard model. Usually, one builds an NHDM scalar sector which is invariant under a certain symmetry group. Although several such groups have been used, no general analysis of symmetries possible in the NHDM scalar sector exists. Here, we make the first step towards this goal by classifying the elementary building blocks, namely the abelian symmetry groups, with a special emphasis on finite groups. We describe a strategy that identifies all abelian groups which are realizable as symmetry groups of the NHDM Higgs potential. We consider both the groups of Higgs-family transformations only and the groups which also contain generalized CP transformations. We illustrate this strategy with the examples of 3HDM and 4HDM and prove several statements for arbitrary N.Comment: 33 pages, 2 figures; v2: conjecture 3 is proved and becomes theorem 3, more explanations of the main strategy are added, matches the published versio

Precision Measurement of KS Meson Lifetime with the KLOE detector

Using a large sample of pure, slow, short lived K0 mesons collected with KLOE detector at DaFne, we have measured the KS lifetime. From a fit to the proper time distribution we find tau = (89.562 +- 0.029_stat +- 0.043_syst) ps. This is the most precise measurement today in good agreement with the world average derived from previous measurements. We observe no dependence of the lifetime on the direction of the Ks.Comment: 5 pages, 7 figure

Efeito do manejo de rebrotas de espécies lenhosas da caatinga sobre o crescimento em altura das hastes.

Resumo: O experimento foi conduzido para avaliar o efeito do manejo de rebrotas de cinco espécies lenhosas da caatinga sobre o crescimento em altura das hastes. As espécies lenhosas foram submetidas aos seguintes tratamentos no delineamento inteiramente casualizado: 1 - preservação de uma haste; 2 - preservação de duas hastes; 3 - preservação de três hastes; 4 - preservação de todas as hastes. As plantas submetidas ao manejo de preservação de uma haste apresentaram maior crescimento de haste e o menor crescimento de haste foi observado para plantas submetidas ao tratamento de preservação de todas as hastes. Dentre as espécies lenhosas estudadas, a jurema preta (Mimosa hostilis) apresentou maior crescimento das hastes e a catingueira (Caesalpinia bracteosa), o menor crescimento de hastes sendo recomendada a sua preservação e uso como recurso forrageiro. A preservação de uma haste por planta propicia o maior crescimento em altura de hastes de espécies lenhosas da caatinga e, a exceção da catingueira, as demais espécies apresentam potencial para produção simultânea de lenha e forragem. [Effect of the management of the sprouts of the tree species of caating on the growth in the height of the stems]. Abstract - The experiment was carried to evaluate the effect of the management of sprouts of five woody species of caatinga on the growth in height of the stems. The woody species were assigned to a completely randomized design to the following treatments: 1-preservation of one stem; 2-preservation of two stems; 3-preservation of three stems; 4-preservation of all of the stems. Plants submitted to the management of preservation of one stem presented larger stem growth and the smallest stem growth was observed for plants submitted to the treatment of preservation of all of the stems. Among the studied woody species, the Mimosa hostilis presented larger growth of the stems and Caesalpinia bracteosa, the smallest growth of stems being recommended to preservation and use as resource forage. The preservation of one stem for plant propitiates the largest growth in height of stems of woody species of caatinga and, the exception of the Caesalpinia bracteosa, the other species present potential for simultaneous production of firewood and forage