Newly discovered biogenic organo halogens with an emphasis on the biologically active examples from marine organisms, bacteria, terrestrial plants and higher life forms, including humans, are focused. Organohalogen compounds represent a valuable and expanding class of natural products, in many cases boasting exceptional biological activity.

The unique experience of designing and conducting a reaction are afforded to the students in a similar way to what one would do in a research lab. It encouraged them to think about each procedural step and its purpose, by the discovery-based procedure.

The environmental significance of acid rain on water systems of different buffer capacities is discussed. The most prevalent natural buffer system is created by the equilibrium between carbonate ions and carbon dioxide.

The spontaneous mixing of helium and air in a helium-inflated balloon is described in an experiment in which the partial pressure of the gases in the balloon are determined from the mole factions and the total pressure measured in the balloon. The results described provide a model for teaching concepts of partial pressure, chemical potential, and…

A review of concepts like tunneling through a metal-molecule-metal-junction, contrast with electrochemical and optical-charge injection, strong-coupling limit, calculations of tunnel transport, electron transfer through Redox-active molecules is presented. This is followed by a discussion of experimental approaches for single-molecule measurements.

The student results are presented for the determination of vanillin in a vanilla extract as part of a problem-solving approach. The determination of the vanillin concentration in the Dutch product "Baukje vanilla extract" is described.

The Sciencenter Museum in Ithaca, New York, materialized from the idea of providing children and museum visitors with hands-on experience of simple chemical activities and puzzles. A brief description and evaluation of the ten fun-filled chemical activities, precautionary measures and management details, are presented.

Descriptions of disciplinary practices can suggest visions of authentic classroom activities. Designing activities that are effective, however, requires an additional framework for identifying a discipline's generative resources -- that is, those learning targets that enable students to make disciplinary sense and progress in subsequent…

The effects of contextual shifts on the partial reinforcement extinction effect (PREE) were studied in autoshaping with rats. Experiment 1 established that the two contexts used subsequently were easily discriminable and equally salient. In Experiment 2, independent groups of rats received acquisition training under partial reinforcement (PRF) or…

Relation priming is a phenomenon in which comprehension of a word pair (e.g., COPPER HORSE) is facilitated by the prior presentation of another word pair (e.g., GLASS EYE) that instantiates the same conceptual relation (i.e., "composed of"). We investigated whether relation priming is contingent on lexical similarity. Study 1 revealed that…

Whether the density of sarcoplasmic reticulum (SR) calcium release channels/ryanodine receptors in the heart declines with age is not clear. We investigated age-related changes in the density of [3H]-ryanodine receptors in crude ventricular homogenates, which contained all ligand binding sites in heart and in isolated junctional SR membranes.…

In the domain of electrical circuits troubleshooting, a full factorial experiment investigated the hypotheses that (a) studying worked examples would lead to better transfer performance than solving conventional problems, with less investment of time and mental effort during training and test, and (b) adding process information to worked examples…

We present the first experimental evidence of a phenomenon in speech communication we call "analog acoustic expression." Speech is generally thought of as conveying information in two distinct ways: discrete linguistic-symbolic units such as words and sentences represent linguistic meaning, and continuous prosodic forms convey information about…

People encode goal-directed behaviors, such as assembling an object, by segmenting them into discrete actions, organized as goal-subgoal hierarchies. Does hierarchical encoding contribute to observational learning? Participants in 3 experiments segmented an object assembly task into coarse and fine units of action and later performed it…

The processing costs involved in regional accent normalization were evaluated by measuring differences in lexical decision latencies for targets placed at the end of sentences with different French regional accents. Over a series of 6 experiments, the authors examined the time course of comprehension disruption by manipulating the duration and…