Realism in energy transition processes: an example from Bohmian quantum mechanics

In this paper we study in details a system of two weakly coupled harmonic oscillators from the point of view of Bohm’s interpretation of quantum mechanics. This system may be viewed as a simple model for the interaction between a photon and a photodetector. We obtain exact solutions for the general case. We then compute approximate solutions for the case where one oscillator is initially in its first excited state (a single photon) reaching the other oscillator in its ground state (the photodetector). The approximate solutions represent the state of both oscillators after the interaction, which is not an eigenstate of the individual hamiltonians for each oscillator, and therefore the energies for each oscillator do not exist in the Copenhagen interpretation of Quantum Mechanics. We use the approximate solutions that we obtained to compute Bohmian trajectories and to study the energy transfer between the oscillators. We conclude that, even using the Bohmian view, the energy of each individual oscillator is not well defined, as the nonlocal quantum potential is not negligible even after the coupling is turned off.     

Modulation of stress consequences by hippocampal monoaminergic, glutamatergic and nitrergic neurotransmitter systems

Several findings relate the hippocampal formation to the behavioural consequences of stress. It contains a high concentration of corticoid receptors and undergoes plastic modifications, including decreased neurogenesis and cellular remodelling, following stress exposure. Various major neurotransmitter systems in the hippocampus are involved in these effects. Serotonin (5-HT) seems to exert a protective role in the hippocampus and attenuates the behavioural consequences of stress by activating 5-HT1A receptors in this structure. These effects may mediate the therapeutic actions of several antidepressants. The role of noradrenaline is less clear and possibly depends on the specific hippocampal region (dorsal vs. ventral). The deleterious modifications induced in the hippocampus by stress might involve a decrease in neurotrophic factors such as brain derived neurotrophic factor (BDNF) following glutamate N-methyl-D-aspartate (NMDA) receptor activation. In addition to glutamate, nitric oxide (NO) could also be related to these effects. Systemic and intra-hippocampal administration of nitric oxide synthase (NOS) inhibitors attenuates stress-induced behavioural consequences. The challenge for the future will be to integrate results related to these different neurotransmitter systems in a unifying theory about the role of the hippocampus in mood regulation, depressive disorder and antidepressant effects.     

Noradrenergic control of odor recognition in a nonassociative olfactory learning task in the mouse

The present study examined the influence of pharmacological modulations of the locus coeruleus noradrenergic system on odor recognition in the mouse. Mice exposed to a nonrewarded olfactory stimulation (training) were able to memorize this odor and to discriminate it from a new odor in a recall test performed 15 min later. At longer delays (30 or 60 min), the familiar odor was no longer retained, and both stimuli were perceived as new ones. Following a post-training injection of the alpha(2)-adrenoceptor antagonist dexefaroxan, the familiar odor was still remembered 30 min after training. In contrast, both the alpha(2)-adrenoceptor agonist UK 14304 and the noradrenergic neurotoxin DSP-4 prevented the recognition of the familiar odor 15 min after the first exposure. Noradrenaline release in the olfactory bulb, assessed by measurement of the extracellular noradrenaline metabolite normetanephrine, was increased by 62% following dexefaroxan injection, and was decreased by 38%-44% after treatment with UK 14304 and DSP-4. Performance of mice in the recall test was reduced by a post-training injection of the beta-adrenoceptor antagonist propranolol or the alpha(1)-antagonist prazosin, thus implicating a role for beta- and alpha(1)-adrenoceptors in the facilitating effects of noradrenaline on short-term olfactory recognition in this model.     

Metaplastic effect of apamin on LTP and paired-pulse facilitation

In area CA1 of hippocampal slices, a single 1-sec train of 100-Hz stimulation generally triggers a short-lasting long-term potentiation (S-LTP) of 1–2 h. Here, we found that when such a train was applied 45 min after application of the small conductance Ca²⁺-activated K⁺ (SK) channel blocker apamin, it induced a long-lasting LTP (L-LTP) of several hours, instead of an S-LTP. Apamin-induced SK channel blockage is known to resist washing. Nevertheless, the aforementioned effect is not a mere delayed effect; it is metaplastic. Indeed, when a single train was delivered to the Schaffer’s collaterals during apamin application, it induced an S-LTP, like in the control situation. At the moment of this LTP induction (15th min of apamin application), the SK channel blockage was nevertheless complete. Indeed, at that time, under the influence of apamin, the amplitude of the series of field excitatory postsynaptic potentials (fEPSPs) triggered by a stimulation train was increased. We found that the metaplastic effect of apamin on LTP was crucially dependent on the NO-synthase pathway, whereas the efficacy of the NMDA receptors was not modified at the time of its occurrence. We also found that apamin produced an increase in paired-pulse facilitation not during, but after, the application of the drug. Finally, we found that the induction of each of these two metaplastic phenomena was mediated by NMDA receptors. A speculative unitary hypothesis to explain these phenomena is proposed.     

Developmental changes in gender composition of friendship networks in adolescent girls and boys

This article describes both normative changes and individual differences in the gender composition of girls' and boys' friendship networks across adolescence and predicts variations in these changes. It also examines changes in the characteristics (context, age difference, closeness, and support) of same- and other-sex friendships in the network. Girls and boys (N=390) were interviewed annually from Grades 6 to 10 (76% retention). Growth in the proportion of other-sex friends was significantly more pronounced for girls and was related to different predictors for girls and boys. Moreover, over time, girls had other-sex friends that were increasingly older than themselves, and most of these friendships took place outside of the school, which was not the case for boys. Growth in the proportion of other-sex friends was more pronounced for secondary than for best friends. Finally, both girls and boys reported receiving higher levels of help from girls than from boys. These findings suggest that other-sex friendships might place some of the girls on a problematic developmental trajectory.     

An examination of the role of perceived support and employee commitment in employee-customer encounters

The authors examined the relationships between perceived organizational support, organizational commitment, commitment to customers, and service quality in a fast-food firm. The research design matched customer responses with individual employees' attitudes, making this study a true test of the service provider-customer encounter. On the basis of a sample of matched employee-customer data (N = 133), hierarchical linear modeling analyses revealed that perceived organizational support had both a unit-level and an employee-level effect on 1 dimension of service quality: helping behavior. Contrary to affective organizational commitment, affective commitment to customers enhanced service quality. The 2 sub-dimensions of continuance commitment to the organization--perceived high sacrifice and perceived lack of alternatives--exerted effects opposite in sign: The former fostered service quality, whereas the latter reduced it. The implications of these findings are discussed within the context of research on employee-customer encounters.     

Control-group study of an intervention training program for youth suicide prevention

Few studies have examined whether training can improve competency in intervening with suicidal youths. In this study we attempted to verify the effectiveness of such a training program on helper competency. Forty-three helpers who received the training were compared with 28 helpers who did not. Participants who received the training improved in knowledge, attitudes, and intervention skills following the training, compared with the control group across measures. Their gains were maintained at 6-month follow-up. In this sample, implementation of a one-time training program improved helpers' competencies in youth suicide intervention.     

Which Helper Behaviors and Intervention Styles are Related to Better Short‐Term Outcomes in Telephone Crisis Intervention? Results from a Silent Monitoring Study of Calls to the U.S. 1–800‐SUICIDE Network

A total of 2,611 calls to 14 helplines were monitored to observe helper behaviors and caller characteristics and changes during the calls. The relationship between intervention characteristics and call outcomes are reported for 1,431 crisis calls. Empathy and respect, as well as factor-analytically derived scales of supportive approach and good contact and collaborative problem solving were significantly related to positive outcomes, but not active listening. We recommend recruitment of helpers with these characteristics, development of standardized training in those methods that are empirically shown to be effective, and the need for research relating short-term outcomes to long-term effects.