A simplification of a completeness proof of Guaspari and Solovay

The modal completeness proofs of Guaspari and Solovay (1979) for their systems R and R ^– are improved and the relationship between R and R ^– is clarified.     

Mechanical output about the ankle in countermovement jumps and jumps with extended knee

In this study the mechanical output (e.g., force, contraction velocity, instantaneous power) about the ankle was measured during a jump with and without occurrence of transportation of power and pre-stretch potentiation. To examine this, a model of the m. triceps surae was used. Eleven subjects performed a maximal one-legged countermovement jump (CMJ) and a maximal one-legged jump with extended knee (EKJ). Ground reaction forces, cinematographic data and electromyograms of m. triceps surae were recorded. The power output, defined as the product of moment and angular velocity, and work done about the ankle were higher during CMJ (1404 W, 130 J) than during EKJ (852 W, 76 J). The peak moments were the same during both jumps. The model of the m. triceps surae showed that the power delivered by m. triceps surae was higher during CMJ than during EKJ, as a result of catapult-action of m. gastrocnemius tendon. The difference in work done is explained, in addition to transportation of energy, by a greater contraction range of m. soleus during CMJ. There is no reason to assume that pre-stretch potentiation plays a role in the difference in mechanical output. The results show that the mechanical output of muscles in complex movements is strongly dependent on the dynamics of the movement, and not only on its contractile capacity.     

A controlled trial of cognitive-behavioural and behavioural treatment of anorexia nervosa

This study was undertaken to investigate whether a cognitive-behavioural treatment procedure was superior to a standard behavioural treatment, in the outpatient therapy of patients with anorexia nervosa. The two treatments were also compared with a control treatment procedure consisting of routine outpatient management. Each group consisted of eight subjects. All the groups showed some improvement, but the findings did not provide support for the prediction that cognitive-behavioural treatment, designed specifically to manipulate both attitudes and behaviour, was superior to the other types of treatment. The implications of the findings are considered.     

Completeness and conservative extension results for some boolean relevant logics

This paper presents completeness and conservative extension results for the boolean extensions of the relevant logic T of Ticket Entailment, and for the contractionless relevant logics TW and RW. Some surprising results are shown for adding the sentential constant t to these boolean relevant logics; specifically, the boolean extensions with t are conservative of the boolean extensions without t, but not of the original logics with t. The special treatment required for the semantic normality of T is also shown along the way.     

INDUSTRIAL SAFETY HAZARD REDUCTION THROUGH PERFORMANCE FEEDBACK

A “feedback package” system, designed to prevent occupational accidents and to fit directly into the normal operations of an industrial organization, was analyzed. Eighteen hazardous conditions in six production departments were assessed during seven observation sessions over a 12-week period, plus four follow-up observations over 4 months. The “feedback package” was presented in multiple baseline fashion, across subjects (department supervisors). It consisted of presenting the supervisor with copies of observational data, accompanied by a note which congratulated good practices and suggested ways for improving safety conditions, along with occasional comments from a senior executive. The results indicated that during the feedback phase, hazard rates were lower and less variable than during the baseline phase. Baseline data were highly variable with peaks ranging from 20 to 55 hazards per department. Following intervention, hazard frequencies dropped by 60%, averaged across departments, with decreases ranging from 29% to 88%. During treatment, data stabilized, with the highest frequency reaching 33. A modified feedback system was implemented by the organization following termination of the study, validating the assumption that such a system would tend to maintain.     

Information Processing and New Ideas — Lateral and Vertical Thinking*

‘Vertical thinking is concerned with digging the same hole deeper. Lateral thinking is concerned with digging the hole somewhere else.’ This is how the author differentiates between the two types of thinking. Education, according to the author, only teaches vertical thinking because lateral thinking has always seemed impossible to teach. He then outlines why (with the increased interest in creativity and the computer) there is growing interest in the thinking processes. Describing how the brain operates and how creative behaviour may be increased Dr. de Bono goes on to discuss the nature of vertical thinking. It is sequential, based on the idea that one must not be wrong, works on the most promising approach, only moves in a planned direction, only considers the relevant, and tends to build up large established patterns. To describe the lateral thinking process the author poses a number of problems discussing their solution and the difficulties which people normally encounter in solving these problems. Finally, he sets out the four main categories of the techniques of lateral thinking; and the reader's attention is drawn to several books which Dr. de Bono has written on the subject.     

Binocular brightness combinations: Additive and nonadditive aspects

A conjoint measurement procedure is used for the measurement of binocular brightness as a function of left and right luminance inputs. For nonzero stimulation, the data confirm earlier findings: the system can be described as additive with a scale exponent of 1. If zero stimulation is included, however, no additive solution can be found (due to Fechner’s paradox). This fact, combined with various critical remarks in the literature with respect to the existence of a real luminance-averaging system, has led us to propose a model which takes account of Fechner’s paradox, and incorporates “realistic” exponents without requiring a multistage processing mechanism where different levels are characterized by different sensory scales. The proposed model makes the weighting coefficients for the two eyes dependent in a continuous way on the strength of stimulation in the two eyes, especially on the amount of contrast of the monocular stimuli. For zero background stimulation, contrast can be expressed in terms of luminance of the stimulus. In this way, the model is reduced to a simple testable form. While it much simpler than Engel’s (1969) model, the experimental results indicate that it might also work for the more general case.