Photographic Effects Produced by Cadmium and Other Elements Under Neutron Bombardment

It has been found that when a duplitized x-ray film has Cd placed next to it and is then surrounded by paraffin and exposed to a neutron source, the film shows blackening under the cadmium. Under these conditions the film also shows some general blackening which is rather weak. The neutrons used in these experiments were obtained by bombarding either Li or Be with about 10 microamperes of 1.2 Mev deuterons furnished by a cyclotron. There are, of course, also p-rays incident on the Cd and the photographic film, and it was necessary to establish the blackening under the cadmium as due to slow neutrons and not to these radiations

Improved primordial non-gaussianity constraints from measurements of galaxy clustering and the integrated Sachs-Wolfe effect

We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cross-correlations with the cosmic microwave background. We update the data sets used by Giannantonio et al. (2012), and broaden that analysis to include the full set of two-point correlation functions between all surveys. In order to obtain the most reliable constraints on PNG, we advocate the use of the cross-correlations between the catalogs as a robust estimator and we perform an extended analysis of the possible systematics to reduce their impact on the results. To minimize the impact of stellar contamination in our luminous red galaxy (LRG) sample, we use the recent Baryon Oscillations Spectroscopic Survey catalog of Ross et al. (2011). We also find evidence for a new systematic in the NVSS radio galaxy survey similar to, but smaller than, the known declination-dependent issue; this is difficult to remove without affecting the inferred PNG signal, and thus we do not include the NVSS auto-correlation function in our analyses. We find no evidence of primordial non-Gaussianity; for the local-type configuration we obtain for the skewness parameter $-36 < f_{\mathrm{NL}} < 45$ at 95 % c.l. ($5 \pm 21$ at $1\sigma$) when using the most conservative part of our data set, improving previous results; we also find no evidence for significant kurtosis, parameterized by $g_{\mathrm{NL}}$. In addition to PNG, we simultaneously constrain dark energy and find that it is required with a form consistent with a cosmological constant.Comment: 24 pages, 16 figures. More conservative treatment of the NVSS data, version accepted by Phys. Rev.

The Nuclear Moments of Indium and Gallium

We have studied the resonance lines of indium using a Fabry-Perot interferometer and find indeed that λ4101 (5p^2P_(1/2)—6s^2'S_(1/2) has four distinct components as reported by Jackson, which, while it does not determine the nuclear moment, requires that it be greater than 1/2

Interpretation of interbasin exchange in an isopycnal ocean model

This work concerns an analysis of inter-basin and inter-layer exchanges in the component ocean part of the coupled ECHAM4/OPYC3 general circulation model, aimed at documenting the simulation of North Atlantic Deep Water (NADW) and related thermohaline circulations in the Indian and Pacific Oceans. The modeled NADW is formed mainly in the Greenland-Iceland-Norwegian Seas through a composite effect of deep convection and downward cross-isopycnal transport. The modeled deep-layer outflow of NADW can reach 16 Sv near 30°S in the South Atlantic, with the corresponding upper-layer return flow mainly coming from the 'cold water path' through Drake Passage. Less than 4 Sv of the Agulhas 'leakage' water contributes to the replacement of NADW along the 'warm water path'. In the South Atlantic Ocean, the model shows that some intermediatte isopycnal layers with potential densities ranging between 27.0 and 27.5 are the major water source that compensate the NADW return flow and enhance the Circumpolar Deep Water (CDW) flowing from the Atlantic into Indian Ocean. The modeled thermohaline circulations in the Indian and Pacific Oceans indicate that the Indian Ocean may play the major role in converting deep water into intermediate water. About 16 Sv of the CDW-originating deep water enters the Indian Ocean northward of 31°S, of which more than 13 Sv 'upwell' mainly near the continental boundaries of Africa, South Asia and Australia through inter-layer exchanges and return to the Antarctic Circumpolar Current (ACC) as intermediate-layer water. As a contrast, only 4 Sv of Pacific intermediate water is connected to 'upwelling' flow southward across 31°S while the magnitude of northward deep flow across 31°S in the Pacific Ocean is significantly greater than that in the Indian Ocean. The model suggests that a large portion of the deep waters, entering the Pacific Ocean (about 14 Sv) 'upwells' continually into some upper layers through the thermocline, and becomes the source of the Indonesian throughflow. Uncertainties in these results may be related to the incomplete adjustment of the model's isopycnal layers and the sensitivity of the Indonesian throughflow to the model's geography and topography

Deuteron Elastic Scattering from He3 and H3

The elastic scattering of deuterons from He3 and H3 has been studied for bombarding energies up to 11 MeV. The excitation curves obtained show a broad resonance in the scattering cross section corresponding to an excitation energy of 20±0.5 MeV in both He5 and Li5. These data, together with H3(d, n)He4 and He3(d, p)He4 data from other sources, tend to indicate that D waves are responsible for the anomaly

Evolution of phage with chemically ambiguous proteomes

BACKGROUND: The widespread introduction of amino acid substitutions into organismal proteomes has occurred during natural evolution, but has been difficult to achieve by directed evolution. The adaptation of the translation apparatus represents one barrier, but the multiple mutations that may be required throughout a proteome in order to accommodate an alternative amino acid or analogue is an even more daunting problem. The evolution of a small bacteriophage proteome to accommodate an unnatural amino acid analogue can provide insights into the number and type of substitutions that individual proteins will require to retain functionality. RESULTS: The bacteriophage Qβ initially grows poorly in the presence of the amino acid analogue 6-fluorotryptophan. After 25 serial passages, the fitness of the phage on the analogue was substantially increased; there was no loss of fitness when the evolved phage were passaged in the presence of tryptophan. Seven mutations were fixed throughout the phage in two independent lines of descent. None of the mutations changed a tryptophan residue. CONCLUSIONS: A relatively small number of mutations allowed an unnatural amino acid to be functionally incorporated into a highly interdependent set of proteins. These results support the 'ambiguous intermediate' hypothesis for the emergence of divergent genetic codes, in which the adoption of a new genetic code is preceded by the evolution of proteins that can simultaneously accommodate more than one amino acid at a given codon. It may now be possible to direct the evolution of organisms with novel genetic codes using methods that promote ambiguous intermediates