Democratizing TV?

Television and the Crisis of Democracy, by Douglas Kellner, Boulder, Co: Westview, 1990, 287 pages, hb £17.95, pb £10.95     

Dynamic stability control during perturbed walking can be assessed by a reduced kinematic model across the adult female lifespan

The current study aimed to determine potential differences in dynamic stability control during perturbed walking across the adult female lifespan and to test the hypothesis that such differences can be assessed by a reduced kinematic model. 11 young-aged (22–30 years), 9 middle-aged (41–59 years) and 14 old-aged (62–75 years) female adults walked on a treadmill while the right leg was unexpectedly perturbed once during the swing phase. Margin of stability (MS) at touchdown was investigated using a full body and a reduced kinematic model. After the perturbation, all age groups showed a lower MS compared to non-perturbed gait (baseline), leading to negative MS. Four old-aged adults failed to cope with the task (only preventing a fall by grasping). The remaining ten old-aged and the middle-aged subjects required three more recovery steps than the young-aged adults to get back to baseline MS. Moreover, there were no differences between kinematic models, and both methods demonstrated similar age-related findings. We concluded that the ability to control dynamic stability during perturbed walking by enlarging the base of support has already begun to deteriorate by middle age. Further, the valid agreement between kinematic models shows that such differences can be assessed by using just four body markers.     

Psychological consequences of collective violence in childhood: the case of Monterrey,Mexico / Consecuencias psicológicas de la violencia colectiva en la niñez: el caso de Monterrey,México

Abstract

During the last years, different types of violence have severely damaged Mexico. In this paper we examine the consequences that violence could have in children, one of the most vulnerable segments of society. In short, we predict that exposure to any type of violence will lead to higher depression and that this could be explained through the effects of violence on childhood well-being. Our hypothesis was supported in two studies, showing that exposure to street violence (Study 1, N = 607) and exposure to collective violence (Study 2, N = 172) can increase childhood depression. Moreover, in both studies, this effect was explained by the decrease of childhood well-being caused by violence exposure. The implications of these results are discussed.     

Sleep Symptoms as a Partial Mediator Between Combat Stressors and Other Mental Health Symptoms in Iraq War Veterans

Sleep symptoms are a prominent feature of mental health disorders like PTSD and depression. However, it is unknown whether sleep symptoms mediate the relationship between combat stress and these disorders. We examined the mediating role of sleep symptoms on the relationship between combat stress and PTSD; and the relationship between combat stress and depression using data from 576 Army veterans of the Iraq War surveyed in 2004. Correlational analyses revealed that when insomnia was included in the model, the correlation between combat stressors and other depression symptoms decreased by 65%; and when nightmares were included in the model, the correlation between combat stressors and other PTSD symptoms decreased by 69%. We replicated these analyses using individual items assessing PTSD and depression and found that the insomnia and nightmare items had the largest and second largest mediation effect between combat stressors and PTSD and depression symptoms. Our result support the theory that sleep symptoms contribute to the development and/or maintenance of other mental health symptoms and that early treatment of sleep symptoms may mitigate the other mental health consequences of combat stress.     

Double bisection of auditory temporal intervals by humans

Scalar Expectancy Theory (SET) has been the leading theory in timing research, and has also influenced research into human timing. However, other timing theories exist, such as Learning to Time (LeT). The double bisection task was designed to test the SET and LeT theories in pigeons. The purpose of this experiment was to verify whether similar results emerge from a human adaptation of the double bisection task. The results indicated that humans perform the double bisection task in the same way as pigeons do. However, the assumptions inherent in LeT cannot be applied to humans. Two other explanations are also assessed here.     

Electron irradiation damage in SnO

In a study of radiation effects in SnO we have found that electron-beam damage is observable from changes in a high-resolution electron microscopy image or electron diffraction pattern. The early stage of the damage is not accompanied by a change in composition or a loss of crystallinity. The dose required for this damage (about 600 C cm^?2) is approximately independent of electron energy (between 100 and 400 keV) and specimen temperature (between 100 and 300 K). The damage is believed to start with displacement of oxygen atoms from their lattice position through a radiolytic mechanism with an efficiency of approximately 10^?4.     

Subjective Situations and Logical Omniscience

The beliefs of the agents in a multi-agent system have been formally modelled in the last decades using doxastic logics. The possible worlds model and its associated Kripke semantics provide an intuitive semantics for these logics, but they commit us to model agents that are logically omniscient. We propose a way of avoiding this problem, using a new kind of entities called subjective situations. We define a new doxastic logic based on these entities and we show how the belief operators have some desirable properties, while avoiding logical omniscience. A comparison with two well-known proposals (Levesque's logic of explicit and implicit beliefs and Thijsse's hybrid sieve systems) is also provided.     

Erna and Melanie Klein

Erna was one of the child patients treated by Melanie Klein in Berlin, employing her recently discovered play technique. Since Erna died in Chile, the authors considered the IPA Congress in Santiago an opportunity to present a paper as a homage both to Erna and, especially, to Klein. She learned much from that very disturbed child, which she later used to sustain the ongoing development of her theories. The paper explores biographic data relevant to understanding both the case and the theories. It analyses the case material to follow Klein in the discovery and the handling of the child's transference and the harsh expressions of hate, jealousy and envy, which are brought in, with sad consequences, by strong persecutory feelings. Klein's comparison of this case with that of Freud's Wolf-man is also considered, mostly to show that the similarities were less than originally claimed, and that Klein, perhaps, was introducing a theoretic shift which led her technique to gradually change from ' Nachträglichkeit ' to the 'signification-resignification' pair, akin to Strachey's concept of the mutative interpretation. Lastly, the comprehension of Erna's strong psychotic traits and the links with later developments of the theory on psychosis are studied.     

Simple discrimination in stingless bees (Melipona quadrifasciata): Probing for select‐ and reject‐stimulus control

Simple and conditional discrimination training may produce various types of controlling relations. Responses may be controlled primarily by the positive stimulus (select–control relation) or by the negative stimulus (reject–control relation; the subject excludes the negative stimulus and chooses the positive). Bees learn to respond in simple and conditional discriminations. However, no study has searched for reject–control responding in Melipona bees. We trained Melipona quadrifasciata on a simple discrimination task (S+ vs. S‐; e.g., blue vs. yellow) and then probed for stimulus control with two types of probe trials, S+ versus a new stimulus (Select–control probes) and S‐ versus a new stimulus (Reject–control probes). For Group Different, a new‐stimulus color (e.g., white) was used in one type of probe and another color (e.g., black) was used in the other type. For Group Same, a single new‐stimulus color was used in both types of probes. On Select probes, the bees always preferred S+ to the new stimulus. On Reject probes, results were mixed. Depending on the colors used in training and probing, bees responded to both stimuli, and even preferred the S‐. The data suggest no control by the negative function of the S‐ and support the select‐stimulus control hypothesis of responding.