The Use of Transactional Analysis with Inquiry Methods in Physics Teaching

We now offer a course that combines an inquiry approach to physics with elementary school science teaching methods and transactional analysis. Our course carries three semester credits in elementary science methods and three semester credits in physics, a total of nine contact hours per week. In previous interim courses the very positive response we have had from our students, i.e., the excitement in discovering some real physics for themselves, and their decision to use the tools of transactional analysis to say OK to themselves and physics, leads us to believe that our course can serve as a useful model for other introductory college science courses

Narrowing the filter cavity bandwidth via optomechanical interaction

We propose using optomechanical interaction to narrow the bandwidth of filter cavities for achieving frequency-dependent squeezing in advanced gravitational-wave detectors, inspired by the idea of optomechanically induced transparency. This not only allows us to achieve narrow bandwidth, comparable to the detection band of few hundred Hz, with tabletop optical cavities, but also to tune the bandwidth over a wide range, which is ideal for optimizing sensitivity for different gravitational-wave sources. The experimental challenge for its implementation is the stringent requirement on low thermal noise, which would need superb mechanical quality factor that is quite difficult to achieve by using currently-available low-loss mechanical oscillators; one possible solution is to use optical dilution of the mechanical damping, which can considerably relax the requirement on the mechanics.Comment: 5 pages + 3 appendix. 4 figures and 2 tables Accepted by Physical Review Letter

Interferometers for Displacement-Noise-Free Gravitational-Wave Detection

We propose a class of displacement- and laser-noise free gravitational-wave-interferometer configurations, which does not sense non-geodesic mirror motions and laser noises, but provides non-vanishing gravitational-wave signal. Our interferometer consists of 4 mirrors and 2 beamsplitters, which form 4 Mach-Zehnder interferometers. By contrast to previous works, no composite mirrors are required. Each mirror in our configuration is sensed redundantly, by at least two pairs of incident and reflected beams. Displacement- and laser-noise free detection is achieved when output signals from these 4 interferometers are combined appropriately. Our 3-dimensional interferometer configuration has a low-frequency response proportional to f^2, which is better than the f^3 achievable by previous 2-dimensional configurations.Comment: 5 pages, 4 figure

Thioxoethenylidene (CCS) as a bridging ligand

The reaction of [Mo(≡CBr)(CO)2(Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with [Fe2(μ-SLi)2(CO)6] affords, inter alia, the unsymmetrical binuclear thioxoethenylidene complex [Mo2(μ,σ(C):η2(C′S)-CCS)(CO)4(Tp*)2], which may be more directly obtained from [Mo(≡CBr)(CO)2(Tp*)] and Li2S. The reaction presumably proceeds via the intermediacy of the bis(alkylidynyl)thioether complex S{C≡Mo(CO)2(Tp*)}2, which was, however, not directly observed but explored computationally and found to lie 78.6 kJ mol–1 higher in energy than the final thioxoethenylidene product. Computational interrogation of the molecules [M2(μ-C2S)(CO)2(Tp*)2] (M = Mo, W, Re, Os) reveals three plausible coordination modes for a thioxoethenylidene bridge which involve a progressive strengthening of the C–C bond and weakening of the M–C and M–S bonds, as might be expected from simple effective atomic number considerations.This work was supported by the Australian Research Council (DP130102598 and DP110101611)

Transcriptome Analysis of \u3ci\u3eBifidobacterium Longum\u3c/i\u3e Strains that Show a Differential Response to Hydrogen Peroxide Stress

Consumer and commercial interest in foods containing probiotic bifidobacteria is increasing. However, because bifidobacteria are anaerobic, oxidative stress can diminish cell viability during production and storage of bioactive foods. We previously found Bifidobacterium longum strain NCC2705 had signifi- cantly greater intrinsic and inducible resistance to hydrogen peroxide (H2O2) than strain D2957. Here, we explored the basis for these differences by examining the transcriptional responses of both strains to sub-lethal H2O2 exposure for 5- or 60-min. Strain NCC2705 had 288 genes that were differentially expressed after the 5-min treatment and 114 differentially expressed genes after the 60-min treatment. In contrast, strain D2957 had only 21 and 90 differentially expressed genes after the 5- and 60-min treatments, respectively. Both strains showed up-regulation of genes coding enzymes implicated in oxidative stress resistance, such as thioredoxin, thioredoxin reductase, peroxiredoxin, ferredoxin, glutaredoxin, and anaerobic ribonucleotide reductase, but induction levels were typically highest in NCC2705. Compared to D2957, NCC2705 also had more up-regulated genes involved in transcriptional regulation and more down-regulated genes involved in sugar transport and metabolism. These results provide a greater understanding of the molecular basis for oxidative stress resistance in B. longum and the factors that contribute to strain-to-strain variability in survival in bioactive food products

Genetic and Physiological Responses of \u3ci\u3eBifidobacterium animalis\u3c/i\u3e subsp. \u3ci\u3elactis\u3c/i\u3e to Hydrogen Peroxide Stress

Consumer interest in probiotic bifidobacteria is increasing, but industry efforts to secure high cell viability in foods is determined by these anaerobes’ sensitivity to oxidative stress. To address this limitation, we investigated genetic and physiological responses of two fully sequenced Bifidobacterium animalis subsp. lactis strains, BL-04 and DSM 10140, to hydrogen peroxide (H2O2) stress. Although the genome sequences for these strains are highly clonal, prior work showed they differ in both intrinsic and inducible H2O2 resistance. Transcriptome analysis of early stationary phase cells exposed to a sub-lethal H2O2 concentration detected significant (P2O2 stress resistance might be due to a mutation in a BL-04 gene encoding long chain fatty acid-coA ligase. To explore this possibility, membrane fatty acids were isolated and analyzed by GC-MS. Results confirmed the strains had significantly different lipid profiles; the BL-04 membrane contained higher percentages of C14:0 and C16:0, and lower percentages of C16:1n7 and C18:1n9. Alteration of the DSM 10140 membrane lipid composition using modified growth medium to more closely mimic that of BL-04 yielded cells that showed increased intrinsic resistance to lethal H2O2 challenge, but did not display an inducible H2O2 stress response. Results show deliberate stress induction or membrane lipid modification can be employed to significantly improve H2O2 resistance in B. animalis subsp. lactis strains

Institutional requirements for optimal water quality management in arid urban areas

Summarizes Completion reports no. 45-47.AER72-73WRW-GVS-RCW-TLH28.Funded in part by the United States Department of the Interior, Office of Water Resources Research, as authorized by the Water Resources Research Act of 1964, and pursuant to Grant Agreement no. 14-31-0001-3567