A General Chemistry Course for Prospective Elementary School Teachers

The paper describes a general chemistry course designed for students who are planning to become elementary school teachers. The course has been structured so as to transmit the fun and excitement of experiencing chemistry and uncovering its basic principles by centering on laboratory and other discovery experiences. In addition, the course uses peer led workshops in which the students discuss these experiences. The course is thus a product of a particularly strong collaboration between public schools and college faculties. It is going to become a part of a new four-course sequence that will be required of all students intending to earn elementary education certification at Lehman College

Generalized Ladder Operators for the Dirac-Coulomb Problem via SUSY QM

The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solve the Dirac-Coulomb problem. The ground state and the excited states are investigated using new generalized ladder operators.Comment: 9 pages, Revtex. Preprint CBPF NF-032/0

Wanted! Nuclear Data for Dark Matter Astrophysics

Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for dark matter particles are under way: production at high-energy accelerators, direct detection through dark matter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle dark matter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor knowledge of cosmic ray activation in detector materials, with order of magnitude differences between simulation codes. A scarcity of data on nucleon spin densities blurs the connection between dark matter theory and experiments. What is needed, ideally, are more and better measurements of spallation cross sections relevant to cosmic rays and cosmogenic activation, and data on the nucleon spin densities in nuclei.Comment: 4 pages, 4 figures. Invited talk at Nuclear Data 2013. To appear in Nuclear Data Sheet

Comment Regarding the Functional Form of the Schmidt Law

Star formation rates on the galactic scale are described phenomenologically by two distinct relationships, as emphasized recently by Elmegreen (2002). The first of these is the Schmidt law, which is a power-law relation between the star formation rate and the column density. The other relationship is that there is a cutoff in the gas density below which star formation shuts off. The purpose of this paper is to argue that 1) these two relationships can be accommodated by a single functional form of the Schmidt law, and 2) this functional form is motivated by the hypothesis that star formation is a critical phenomenon, and that as a corollary, 3) the existence of a sharp cutoff may thus be an emergent property of galaxies, as was argued by Seiden (1983), as opposed to the classical view that this cutoff is due to an instability criterion.Comment: 14 pages, 3 figures, in press, New Astronomy. Figs provided in original (png) format as well as ps format for ps/pdf generatio

The activation of hydrogen by excited mercury atoms

That mercury atoms excited by absorption of the line 2537Å are able to activate various kinds of atoms by collisions of the second kind has been shown in several different ways. Using pressure measurements to follow the reaction, Cario and Franck (1) showed that hydrogen, in the presence of excited mercury vapor, can be activated and made to reduce copper oxide or tungsten oxide, while Dickinson (2) repeated the experiment using gaseous oxygen instead of solid oxide. Employing spectroscopic methods of detection, Cario (3) activated thallium vapor by collisions with excited mercury atoms and observed the radiation of the green thallium line 5351 Å and indeed all the thallium lines which would theoretically be expected

The interplanetary hydrogen and helium glow and the inferred interstellar gas properties

Observations of the interplanetary hydrogen and helium glow have been obtained by a number of spacecraft and rocket experiments during the past fifteen years. Important results have been established on the temperature, density, velocity, spatial dependence, and hydrogen to helium ratio. However, only four spacecraft launched to date are investigating the outer solar system and of these four the Pioneer 10 spacecraft is the farthest out at 28 A.U. Observations from this spacecraft at great distances have permitted an improved analysis of the effects which are only evident at large distances from the Sun. Perhaps the most significant result in this regard is the clear evidence of the importance of multiple scattering of solar Ly-alpha; an effect which has not been observed in earlier work. Ignoring this effect can lead to a gross overestimate of the local galactic glow. Current best estimates of the galactic glow and the local interstellar wind parameters obtained by the Pioneer 10 photometer at great distances are presented, in addition to complementary experimental observations of particular interest

Anion-Dependent Construction of Two Hexanuclear 3D-4F Complexes with a Flexible Schiff Base Ligand

Two hexanuclear 3d-4f Ni-Eu and Cu-Eu complexes [Eu4Ni2L2(OAc)(12)(EtOH)(2)] (1) and [Eu4Cu2L2(OAc)(12)]center dot 2H(2)O (2) are reported which are formed from the salen type Schiff-base ligand H2L (H2L = N,N'-bis(3-methoxysalicylidene)butane-1,4-diamine). In both complexes, four Eu3+ cations are bridged by eight OAc- groups and the chain is terminated at each end by two ML (M = Ni and Cu) units. The structures of 1 and 2 were determined by single crystal X-ray crystallographic studies and the luminescence properties of the free ligand and metal complexes in solution were measured.HHMI Undergraduate Science Education Award 52005907National Science Foundation CHE-0629136, CHE-0741973, CHE-0847763Welch Foundation F-1631, F-816Hong Kong Baptist University FRG/06-07/II-16Hong Kong Research Grants Council HKBU 202407Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Open Foundation of Jiangsu Province Key Laboratory of Fine Petrochemical Technology KF1005UT-CNM and UT-AustinChemistr

Covariant quantum measurements may not be optimal

Quantum particles, such as spins, can be used for communicating spatial directions to observers who share no common coordinate frame. We show that if the emitter's signals are the orbit of a group, then the optimal detection method may not be a covariant measurement (contrary to widespread belief). It may be advantageous for the receiver to use a different group and an indirect estimation method: first, an ordinary measurement supplies redundant numerical parameters; the latter are then used for a nonlinear optimal identification of the signal.Comment: minor corrections, to appear in J. Mod. Opt. (proc. of Gdansk conf.