12,319 research outputs found
Two-photon detuning and decoherence in cavity electromagnetically induced transparency for quantized fields
The interaction of a quantized field with three-level atoms in
configuration inside a two-mode cavity is analyzed in the small noise
approximation. The atoms are in a two-photon detuning with respect to the
carriers of the field. We calculate the stationary quadrature noise spectrum of
the field outside the cavity in the case where the input probe field is a
squeezed state and the input pump field is a coherent state. The mean value of
the field is unaltered in all the analysis: the atoms shows electromagnetically
induced transparency (EIT). The effect of the atoms' base level decoherence in
the cavity output field is also studied. It is found that the output field is
very sensitive to two-photon detuning.Comment: 8 page
Message handling system concepts and services in a land mobile satellite system
A network architecture containing the capabilities offered by the Message Handling System (MHS) to the PRODAT Land Mobile Satellite System (LMSS) is described taking into account the constraints of a preexisting satellite system which is going to become operational. The mapping between MHS services and PRODAT requirements is also reported and shows that the supplied performance can be significantly enhanced to both fixed and mobile users. The impact of the insertion of additional features on the system structure, especially on the centralized control unit, are also addressed
Antecedents and consequences of parental psychological control and autonomy support: the role of psychological basic needs
Research suggest that psychologically controlling and autonomy supportive parenting can be described within the SDT's framework. Two studies were conducted to examine: (a) the role of parental need frustration as a predictor of parental psychological control, (b) the role of parental need satisfaction as a predictor of parental autonomy support and (c) the role of parents' psychological control and autonomy support in the intergenerational transmission of satisfaction and frustration of the psychological basic needs. Study-1 provided evidence, in a sample of 203 Italian coupled parents, that needs frustration and needs satisfaction represent distinct antecedents of psychological control and autonomy support. Study-2, showed that in 135 families, the intergenerational association between parents' and adolescents' need frustration was partial mediated by psychological control and autonomy support. Results clearly showed that parents who experienced high level of psychological needs frustration are more likely to use psychological control and in turn to promote a feeling of need frustration in their adolescents; differently, parents who experienced high levels of psychological needs satisfaction tend to exert more autonomy support in their relationship with their children and in turn adolescents tend to perceive higher level of needs satisfaction. These findings are discussed in light of SDT and underline the importance of needs in the parenting context and have implications for interventions
Resonant Axisymmetric Modes
Axisymmetric modes in shaped tokamak plasmas are normally associated with vertical displacement events. However, not enough attention has been given to the fact that these modes can be resonant in two different ways. Firstly, for a plasma bounded by a divertor separatrix, a generic n=0 ideal-MHD perturbation, ξ, is singular at the divertor X- point(s), where Beq · ∇ξ = 0, with Beq the equilibrium magnetic field. As a consequence, n=0 perturbations can give rise to current sheets localized along the divertor separatrix. Secondly, a feedback-stabilized n=0 mode tends to acquire an Alfv ́enic oscillation frequency. As a result, a resonant interaction with energetic particle orbits can lead to a new type of fast ion instability
Antibacterial properties of imipenem with special reference to the activity against methicillin-resistant staphylococci, cefotaxime-resistant Enterobacteriaceae and Pseudomonas aeruginosa
Imipenem was examined with standardized agar dilution procedures against a wide range of bacteria. Geometric mean MICs against the genera Escherichia, Klebsiella, Enterobacter, Citrobacter and Serratia were 0·1-0·4 mg/1, and Proteus and Providencia spp. were inhibited by 0·25-4 mg/1. Acinetobacter calcoaceticus var. anitratum strains were inhibited by concentrations ranging from 0·12-0·5 mg/1. Methicillin-susceptible staphylococci were highly susceptible to the drug (MICs: ⩾0·03 mg/1) and enterococci were inhibited by 0·25-16 mg/1. Most of the multi-resistant JK corynebacteria were resistant to imipenem. Imipenem was more active than any other ß-lactam against methicillin-resistant staphylococci; this was also demonstrated in a population analysis. Imipenem-resistant minorities in populations, however, were also observed. Cefotaxime-resistant and -intermediate Enterobacter and Citrobacter strains were inhibited by concentrations of 0·5 mg/1 or less. No third-generation cephalosporin nor any other ß-lactam showed similarly high activity against these groups of organisms. Among 20 ceftazidime-resistant and 20 ceftazidime-susceptible isolates of Pseudomonas aeruginosa, no strain was resistant and only five ceftazidime-resistant strains were intermediately susceptible (MIC, 8 mg/1) to imipene
How parental autonomy support prevent from adolescents’ depression and low self-esteem: a mediational model with trait Emotional Intelligence
Objective: The main aim of this study was to deepen the literature about parental autonomy support, analysing the relation between its two dimensions, Promotion of Independence (PI) and Promotion of Volitional Functioning (PVF), and adaptive outcomes in adolescents. Specifically, it was hypothesized that both components would predict higher self-esteem and lower depression in adolescents, through the mediation of trait Emotional Intelligence (trait EI). Method: A total of 283 adolescents, aged between 14 and 17 years (M=15.53; SD=1.21), participated in this study. They completed the Center for Epidemiologic Studies- Depression Scale (CES-D), the Promotion of Independence (PI) and Promotion of Volitional Functioning (PVF), the Rosenberg Self-Esteem and Trait Emotional Intelligence Questionnaire- Adolescent Short Form (TEIQue-ASF). Results: It was found that parental autonomy support predicted trait EI, which in turn fully mediated the relation between supportive practices and psychological outcomes in adolescents, with several interesting parent gender differences. Conclusions: This study highlights how autonomy-supportive practices are fundamental for healthy and adequate development of emotional intelligence in adolescents. It also contributes to the advancement of research on the contextual and individual mechanisms underlying the functional adaptation of offspring
The influence of pulsed redox conditions on soil phosphorus
The effects of eleven pulsed reduction-oxidation cycles (20 and 2 days respectively) on soil phosphorus (P) dynamics are compared for 12 soils having contrasting properties and overfertilised with respect to P. Incubation conditions simulated transient waterlogging of the soil profile and involved repeated sampling and analysis of both the solution and solid phase P forms. An initial increase in P concentration occurred upto and including the fourth full cycle was followed by a sharp decline in concentration for all but one soil. Accompanying changes in the main extractable forms of P, which appeared to be cumulative, could be summarised as a general decline in the organic P fraction and an overall increase in amorphous associated inorganic forms of P. The fact that up to 60% of the total soil P was demonstrated to change its sensitivity for a particular extractant suggests that these operationally defined P forms can experience substantial transformations. There was also a suggestion that certain changes in P forms may not be reversible. While the laboratory conditions represent an extreme situation changes in timing and frequency of intense precipitation events, as predicted in many climate change scenarios, may increase the risk of episodic soil waterlogging. The potential onset of reducing conditions even for periods of less than twenty days will influence soil P dynamics and short-term bioavailable P. Various mechanisms are involved but the robustness of sequential extraction procedures and general soil test methods (e.g. Olsen) for quantifying and reliably distinguishing specific soil P forms/associations are questioned
Comments on the Quark Content of the Scalar Meson
Based on the measurements of we determine, in
a model independent way, the allowed content in the scalar meson
. We find that, on the one hand, if this isoscalar resonance is a
pure state [ , a very
large -annihilation term will be needed to accommodate . On the other hand, the component of
should be small enough to avoid excessive induced
from the external -emission. Measurement of production in the
decay will be useful to test the above picture. For the
decay which is kinematically barely or even not
allowed, depending on the mass of , we find that the finite width
effect of plays a crucial role on the resonant three-body decay
.Comment: 12 pages, 2 figure
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