Angular homeostasis: IV. Polygonal orbits

Some properties are discussed of regular polygons that may result from angular homeostatic processes in stable orbit. To characterize these homeostatic polygons we need to discuss the winding number, the sidedness (integer, fractional and irrational), multiplicity, envelopes, and density. A regular (i.e., equilateral, equiangular) polygon may be closed in one revolution about its unique center, in multiple revolutions, or not at all. A homeostatic polygon can be generated only if all vertices are included in a single polygon, which occurs if and only if the number of vertices and the number of revolutions required to complete the polygon are relatively prime. For the homeostatic polygon to have a finite number of sides (without repeating itself) the angle subtended by any two successive vertices at the center must be a rational multiple of 2. Biological implications of these properties are illustrated.     

THE CREATIONISTS

Abstract. As the crusade to outlaw the teaching of evolution changed to a battle for equal time for creationism, the ideological defenses of that doctrine also shifted from primarily biblical to more scientific grounds. This essay describes the historical development of "scientific creationism" from a variety of late–nineteenth– and early–twentieth–century creationist reactions to Charles Darwin's theory of evolution, through the Scopes trial and the 1960s revival of creationism, to the current spread of strict creationism around the world.     

Treating Young Adult Depression With Text-Delivered Cognitive Behavioral Therapy: A Pilot Randomized Clinical Trial

Young adults (ages 18 to 25) in the U.S. suffer from the highest rates of past-year major depressive episode and are the least likely to receive treatment compared to other age groups. As such, we examined the feasibility, acceptability, and efficacy of a text-message delivered cognitive behavioral therapy: CBT-txt with young adults. The study was a 2-month pilot RCT to test a 4-week intervention for depression that contained 197 text messages (average 12 texts every other day). The sample, recruited via Facebook and Instagram, was 102 U.S. young adults who presented with at least moderate depressive symptomatology. Assessments occurred at baseline prior to randomization and at 1 and 2 months post enrollment. The primary outcome, severity of depressive symptoms, was assessed using the Beck Depression Inventory II. Feasibility benchmarks were met and participants reported high levels of engagement with and acceptability of the intervention. Logistic regression indicated that treatment participants were three times as likely to have minimal or mild depression symptoms at 2 months compared to waitlist control participants. Latent change score modeling found that the strongest significant treatment effect appeared at the 1-month follow-up period, particularly for participants who began with severe depressive symptoms. Mediation analysis revealed significant indirect treatment effects of increases in behavioral activation on reducing depressive symptoms, suggesting a mechanism of change. Limitations were that the sample was relatively small and consisted of primarily women. These results provide initial evidence for the feasibility, acceptability, and efficacy of a text-delivered treatment for young adult depression.     

单眼视剥夺2小时对雏鸡记忆保持的影响

以2日龄雏鸡为研究对象,采用一次性被动回避学习模型,以不透明胶纸封贴一侧眼的方法,研究2日龄雏鸡单侧眼视剥夺2小时后对视觉学习记忆的影响,并与双眼学习条件下的记忆情况进行比较;试图探讨雏鸡在视觉信息加工过程中左、右半球的作用。实验结果表明：剥夺一侧眼（无论左或右）2小时后对雏鸡的短时记忆无影响,明显干扰雏鸡的中期和长时记忆,特别是剥夺左眼干扰更明显。     

Choice and multiple reinforcers

Pigeons chose between equivalent two-component mixed and multiple terminal-link schedules of reinforcement in the concurrent-chains procedure. The pigeons preferred the multiple schedule over the mixed when the components of the compound schedules were differentiated in terms of density of reinforcement, but the pigeons were indifferent when the components were differentiated in terms of number of reinforcers per cycle. Taken together, these results indicate that a local variable, the interval to the first reinforcer, but not a molar variable, the number of reinforcers, was sufficient to differentiate the components and thereby evoke preference.     

Latent roots of random data correlation matrices with squared multiple correlations on the diagonal: A monte carlo study

In order to make the parallel analysis criterion for determining the number of factors easy to use, regression equations for predicting the logarithms of the latent roots of random correlation matrices, with squared multiple correlations on the diagonal, are presented. The correlation matrices were derived from distributions of normally distributed random numbers. The independent variables are log (N–1) and log {[n(n–1)/2]–[(i–1)n]}, whereN is the number of observations;n, the number of variables; andi, the ordinal position of the eigenvalue. The results were excellent, with multiple correlation coefficients ranging from .9948 to .9992.This research was supported by the Office of Naval Research under Contract N00014-67-A-0305-0012, Lloyd G. Humphreys, principal investigator, and by the Department of Computer Science of which Richard G. Montanelli, Jr., is a member.     

Dimensional stimulus control following brief wavelength training

Pigeons with extensive training pecking a key illuminated by a white line then had brief training with the key illuminated by 555 nanometers. This was immediately followed by a wavelength generalization test in extinction. Dimensional stimulus control about the training wavelength increased with the duration and number of reinforcements given on variable-interval 30-sec and variable-interval 10-sec schedules in Experiment I. In Experiment II, dimensional stimulus control was obtained after only 4 min of wavelength training from birds with prior and independent discrimination training. Experiment III provided groups equated in number of reinforcers with groups in Experiment I and two 8-min duration groups. Analyses, which included results from both Experiments I and III, showed that dimensional stimulus control increased: (a) more rapidly as a function of the duration of variable-interval 10-sec than variable-interval 30-sec reinforcement; (b) at the same rate across variable-interval reinforcement schedules, as a function of the number of reinforcers available during brief wavelength training.     

友伴人际品格对儿童人际品格的影响:友伴数量的调节作用及儿童群体差异

友伴是儿童发展的重要影响源。本研究从儿童积极发展的视角探讨友伴人际品格（仁慈和公正）对儿童人际品格的影响及友伴数量在其中的调节作用,并检验了儿童的群体（学段、性别、是否独生）差异状况。研究采用班级同伴提名法及儿童品格调查问卷对1555名4~9年级儿童及其互提名友伴展开调查。结果发现：（1）友伴仁慈和公正显著预测所有儿童群体的仁慈和公正;（2）儿童的友伴数量更多时,友伴公正对其公正的预测作用更显著;该调节效应仅体现在初中生和男生群体上。研究结果表明,儿童与具有积极品格特征的友伴交往对其积极品格的发展至关重要,且对于特定群体（如初中生、男生）,与越多具有积极品质的友伴交往,其受到的积极影响越大。