This article presents a hands-on experiment that covers many areas of high school mathematics. Included are the notions of patterns, proof, triangular numbers and various aspects of problem solving. The problem involves the arrangements of a school of fish using split peas or buttons to represent the fish. (Contains 4 figures.)

Down syndrome (DS) is a genetic disorder arising from the presence of a third copy of the human chromosome 21 (Hsa21). Recently, O'Doherty and colleagues in an earlier study generated a new genetic mouse model of DS (Tc1) that carries an almost complete Hsa21. Since DS is the most common genetic cause of mental retardation, we have undertaken a…

This paper reports results from a "natural experiment" taking place in China on the impact of dogs on owners' health. Previous Western research has reported modest health benefits, but results have remained controversial. In China pets were banned in urban areas until 1992. Since then dog ownership has grown quite rapidly in the major…

Washoe, the chimpanzee pioneer who learned aspects of American Sign Language, died in October 2007. In reviewing her life and accomplishments, this article focuses on Washoe's status as an ape and a person, and on the role of emotion in language learning and language use. It argues that Washoe's legacy stems not from the number of ASL signs she…

The role of sensory feedback in the early ontogeny of motor coordination remains a topic of speculation and debate. On E20 of gestation (the 20th day after conception, 2 days before birth), rat fetuses can alter interlimb coordination after a period of training with an interlimb yoke, which constrains limb movement and promotes synchronized,…

In mammalian species, behavior begins in utero, hidden within the mother's body. This biological fact has made it difficult to observe or to access fetuses, leaving the beginnings of behavior to the imagination or allowing it to be forgotten or ignored. Such truncation of perspective probably helped many to consider behavioral capabilities first…

Fundamental questions in cognitive science concern the origins and nature of the units that compose visual experience. Here, we investigate the capacity to individuate and store information about non-solid portions, asking in particular whether free-ranging rhesus monkeys ("Macaca mulatta") quantify portions of a non-solid substance presented in…

A robust finding in humans and animals is that intermixed exposure to 2 similar stimuli (AX/BX) results in better discriminability of those stimuli on test than does exposure to 2 equally similar stimuli in 2 separate blocks (CX_DX)--the intermixed-blocked effect. This intermixed-blocked effect may be an example of the superiority of spaced over…

The present studies examined whether the retrieval of an old "reactivated" memory could be brought under the control of new contextual cues. In Experiment 1 rats trained in one context were exposed to different contextual cues either immediately, 60 or 120 min after a cued reactivation of the training memory. When tested in the shifted context,…

We describe the construction and operation of three low-cost schlieren imaging systems that can be fabricated using surplus optics and 80/20, an aluminium extrusion based construction system. Each system has a different optical configuration. The low cost and ease of construction makes these systems highly suitable for high-school and…

The present article deals with the problem of combined harvesting of a Michaelis-Menten-type ratio-dependent predator-prey system. The problem of determining the optimal harvest policy is solved by invoking Pontryagin's Maximum Principle. Dynamic optimization of the harvest policy is studied by taking the combined harvest effort as a dynamic…

People know little about the non-domesticated animals that live around them. Somehow, they seem remote. In stories they hear about them, animals are often acting, speaking, and dressing like people. This article presents a lesson where students learn about the native species of their area while exploring the concept of interdependence through…

Learning strategy selection was assessed in two different inbred strains of mice, C57BL/6 and DBA/2, which are used for developing genetically modified mouse models. Male mice received a training protocol in a water maze using alternating blocks of visible and hidden platform trials, during which mice escaped to a single location. After training,…

In the past few months, animal-rights groups have stepped up their demonstrations against academic researchers who use animals, spawning a new wave of concern among scientists. In February, extremists caused a fire at the home of a researcher from the University of California at Los Angeles, and protesters struck the husband of a scientist from…