Why the Hardest Logic Puzzle Ever Cannot Be Solved in Less than Three Questions

Rabern and Rabern (Analysis 68:105–112 2) and Uzquiano (Analysis 70:39–44 4) have each presented increasingly harder versions of ‘the hardest logic puzzle ever’ (Boolos The Harvard Review of Philosophy 6:62–65 1), and each has provided a two-question solution to his predecessor’s puzzle. But Uzquiano’s puzzle is different from the original and different from Rabern and Rabern’s in at least one important respect: it cannot be solved in less than three questions. In this paper we solve Uzquiano’s puzzle in three questions and show why there is no solution in two. Finally, to cement a tradition, we introduce a puzzle of our own.     

Enhancing effects of acute psychosocial stress on priming of non-declarative memory in healthy young adults

Social stress affects cognitive processes in general, and memory performance in particular. However, the direction of these effects has not been clearly established, as it depends on several factors. Our aim was to determine the impact of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) reactivity to psychosocial stress on short-term non-declarative memory and declarative memory performance. Fifty-two young participants (18 men, 34 women) were subjected to the Trier Social Stress Task (TSST) and a control condition in a crossover design. Implicit memory was assessed by a priming test, and explicit memory was assessed by the Rey Auditory Verbal Learning Test (RAVLT). The TSST provoked greater salivary cortisol and salivary alpha-amylase (sAA) responses than the control task. Men had a higher cortisol response to stress than women, but no sex differences were found for sAA release. Stress was associated with an enhancement of priming but did not affect declarative memory. Additionally, the enhancement on the priming test was higher in those whose sAA levels increased more in response to stress (r(48)?=?0.339, p?=?0.018). Our results confirm an effect of acute stress on priming, and that this effect is related to SNS activity. In addition, they suggest a different relationship between stress biomarkers and the different memory systems.     

Burnout and job satisfaction among nursing professionals

The purpose of this study was to examine the relationship between burnout and job satisfaction among nursing professionals. The sample consisted of 316 staff nurses. The study was longitudinal, and not randomized. The gap between Time 1 (T1) and Time 2 (T2) was one year. Hierarchical regression analysis showed empirical evidence of the significant and negative effect of burnout (i.e., Emotional exhaustion and Depersonalization dimensions) at T1 on job satisfaction in T2. Significant results were also obtained that showed the influence of job satisfaction at T1 on burnout at T2 (i.e., Depersonalization dimension). The study concludes that there is a bidirectional and longitudinal relationship between burnout and job satisfaction. However, longitudinal effects of burnout at T1 on job satisfaction on T2 (i.e., burnout as antecedent of job satisfaction) are stronger than vice-versa (i.e., job satisfaction as antecedent of burnout).     

Prediction of mathematics achievement: effect of personal, socioeducational and contextual variables

Based upon the self-regulated learning theoretical framework this study examined to what extent students' Math school achievement (fifth to ninth graders from compulsory education) can be explained by different cognitive-motivational, social, educational, and contextual variables. A sample of 571 students (10 to 15 year old) enrolled in the study. Findings suggest that Math achievement can be predicted by self-efficacy in Math, school success and self-regulated learning and that these same variables can be explained by other motivational (ej., achievement goals) and contextual variables (school disruption) stressing this way the main importance of self-regulated learning processes and the role context can play in the promotion of school success. The educational implications of the results to the school levels taken are also discussed in the present paper.     

Photoelectric-helicoidal spirometer

This paper describes a photoelectric-helicoidal spirometer that has been designed in our laboratory. It includes a cylindrical helix (or turbine) partitioned in each of its blades by means of opaque plates transversally disposed. These plates obstruct the ray of light emitted by a diode, preventing it from reaching a photoreceptor located at the opposite side of the turbine. These basic elements are located in a module that can be adjusted to a mask that covers nostrils and mouth. Control software for this device is also described. The software facilitates a graphical representation of respiratory activity, as well as its storage in the computer. Software has been designed to be adaptable to any digital-to-analog converter. Both the device and the software have several advantages over traditional spirometers, as well as other nonspirometric techniques for studying respiratory activity.     

Centrality ratings,forensic relevance,and production frequency: Which one best identifies central and peripheral items?

Production frequency has often been used to identify central and peripheral information, under the assumption that high frequency implies that the item is central. However, no research to date has tested the relationship between centrality and frequency. Participants watched a video of a bank robbery and completed a free recall test, from which frequency for recalled items was computed. Two groups then watched the same video and rated centrality and forensic relevance for each item. Results showed that most, but not all, items with high frequency were rated as central and forensically relevant but that low frequency items were not diagnostic of either item centrality or forensic relevance. Forensic relevance was a better indicator of item centrality than frequency. We concluded that frequency measures should be avoided to determine centrality. Also, if centrality ratings cannot be collected, forensic relevance ratings may be more appropriate for this purpose.     

Association of daytime sleepiness and the morningness/eveningness dimension in young adult subjects in Brazil

Sleepiness is a major public health problem associated with motor vehicle crashes, occupational accidents, decreased productivity, and interpersonal problems. It can be influenced by many factors, including the individual's circadian rhythm. The objective of this study is to assess the correlation between the morningness/eveningness dimension and daytime sleepiness in medical school students. This is a cross-sectional study; 310 subjects (123 women and 187 men, M age 20.5 +/- 1.9 yr.) completed a questionnaire on use of drugs, diagnostic diseases, sleeping habits, the Morningness/Eveningness Questionnaire and the Epworth Sleepiness Scale. The only variable related to daytime sleepiness was the morningness/eveningness dimension (r = -.18, p=.002). Questions with higher coefficients of discrimination between the morning and the evening chronotype were "Lying down to rest in the afternoon when circumstances permit" (.61), "Sitting and reading" (.53), and "As a passenger in a car for an hour without a break" (.53). The implications of the findings are discussed.     

Structural validity and reliability of the Spanish version of the White Bear Suppression Inventory (WBSI) in a sample of the general Spanish population

This paper introduces the validation of the Spanish adaptation of the White Bear Suppression Inventory (WBSI) by Wegner and Zanakos (1994). A sample of 833 people from the general population completed the WBSI along with other questionnaires. The exploratory factor analysis and the confirmatory factor analysis supported a two-factor solution accounting for 51.8% of the cumulative variance. This structure is comprised of the two following factors: unwanted intrusive thoughts (alpha = .87, r = .70) and actions of distraction and suppression of thoughts (alpha = .80, r = .60). Both internal consistency reliability (alpha = .89) and test-retest reliability (r = .71) showed adequate homogeneity, sound consistency, and stability over time. The results are discussed bearing in mind both isolated factors and the possible relationships of the suppression factor with automatic negative thoughts and insomnia.     

Time course of attentional bias to emotional scenes in anxiety: Gaze direction and duration

Pictures of emotionally neutral, positive, and negative (threat- or harm-related) scenes were presented for 3 seconds, paired with nonemotional control pictures. The eye fixations of high and low trait anxiety participants were monitored. Intensity of stimulus emotionality was varied, with two levels of perceptual salience for each picture (colour vs. greyscale). Regardless of perceptual salience, high anxiety was associated with preferential attention: (a) towards all types of emotional stimuli in initial orienting, as revealed by a higher probability of first fixation on the emotional picture than on the neutral picture of a pair; (b) towards positive and harm stimuli in a subsequent stage of early engagement, as shown by longer viewing times during the first 500 ms following onset of the pictures; and with (c) attention away from (i.e., avoidance) harm stimuli in a later phase, as indicated by shorter viewing times and lower frequency of fixation during the last 1000 ms of picture exposure. This suggests that the nature of the attentional bias varies as a function of the time course in the processing of emotional pictures.     

Parenting practices and internalizing and externalizing problems in Spanish adolescents

The goal of this study was to analyze the relationship between parenting practices and internalizing and externalizing problems presented by a group of adolescents according to their gender. Four hundred and sixty-nine secondary school students (aged between 12 and 18) participated in this study. The adolescents presented differences in perception of the educational practices of both parents as a function of their gender. Negative parenting practices were positively related to adolescents' internalizing and externalizing problems, whereas positive practices were negatively related to externalizing problems. Moreover, differences between boys and girls were found in predictor variables of problems, and the predictive power of the variables was higher for externalizing problems.