Hyperfine Structure of Thallium Bromide

The hyperfine structure of the J  =  2J=2 and J  =  3J=3 rotational states of TlBr has been measured with a molecular‐beam electric resonance spectrometer. Hyperfine transition frequencies were measured under conditions of very weak electric and magnetic fields. The linewidth was 500 Hz. The hyperfine interaction constants have been determined for 205Tl79Br, 203Tl79Br, 205Tl81Br, and 203Tl81Br in the first five vibrational states for J  =  2J=2. In addition, the interaction constants for J  =  3,υ  =  0J=3,υ=0 were determined for Tl79Br and Tl81Br, but it was not possible to resolve the effect of the two thallium isotopes in the J  =  3J=3 state. The spectra measured are well described by a hyperfine Hamiltonian containing the bromine quadrupole interaction, the spin–rotation interactions of both the thallium and the bromine nuclei, and both the scalar and tensor parts of the spin–spin interaction between the nuclei. The dependence of the magnetic hfs constants on vibrational state and on isotopic composition shows good agreement with theory. The magnetic octupole interaction of the bromine nucleus in TlBr is negligibly small, and we find no evidence for nuclear polarization or pseudoquadrupole effects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70429/2/JCPSA6-53-4-1525-1.pd

Sex-Specific Effects of Prenatal Glucocorticoids on Placental Development

Abstract not availabl

Morphologies of Galaxies in and around a Protocluster at z=2.300

We present results from the first robust investigation of galaxy morphology as a function of environment at z>1.5. Our study is motivated by the fact that star-forming galaxies contained within a protocluster at z=2.3 in the HS1700+64 field have significantly older ages and larger stellar masses on average than those at similar redshifts but more typical environmental densities. In the analysis of HST/ACS images, we apply non-parametric statistics to characterize the rest-frame UV morphologies of a sample of 85 UV-selected star-forming galaxies at z=1.7-2.9, 22 of which are contained in the protocluster. The remaining 63 control-sample galaxies are not in the protocluster but have a similar mean redshift of ~2.3. We find no environmental dependence for the distributions of morphological properties. Combining the measured morphologies with the results of population synthesis modeling, we find only weak correlations, if any, between morphological and stellar population properties such as stellar mass, age, extinction and star-formation rate. Given the incomplete census of the protocluster galaxy population, and the lack of correlation between rest-frame UV morphology and star-formation history at z~2 within our sample, the absence of environmental trends in the distribution of morphological properties is not surprising. Additionally, using a larger sample of photometric candidates, we compare morphological distributions for 282 UV-selected and 43 near-IR-selected galaxies. While the difference in the degree of nebulosity between the two samples appears to be a byproduct of the fainter average rest-frame UV surface brightness of the near-IR-selected galaxies, we find that, among the lowest surface brightness galaxies, the near-IR-selected objects have significantly smaller angular sizes (abridged).Comment: 25 pages including 16 figures. Accepted for publication in ApJ. Version with full resolution figures available at http://www.astro.princeton.edu/~apeter/LBG/papers/peter2007_fullres.ps.g

Molecular Beam Measurement of the Hyperfine Structure of 85Rb19F

Radio‐frequency transitions between the hfs levels of the J=1 rotational state in 85Rb19F have been observed using a molecular beam electric resonance spectrometer. From these spectra we have obtained values for the constant eq1Q1, which characterizes the interaction between the electric quadrupole moment of the Rb nucleus with the molecular electric‐field gradient; for the constants c1 and c2 which characterize the magnetic interaction between the Rb and F nuclei, respectively, and the rotational angular momentum J of the molecule; and for the constants c3 and c4 which describe the magnetic coupling of the two nuclear spins. Measurements have been made on the first‐five vibrational states. The results for v=0 areeq1Q1=(−70.342±0.001)MHz,c1=(+0.52±0.02)kHz,c2=(+10.615±0.06)kHz,c3=(+0.80±0.06)kHz,c4=(+0.15±0.05)kHz.Values of these constants for v=1, 2, 3, and 4 are given with somewhat less precision.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69352/2/JCPSA6-45-10-3731-1.pd

Triple Resonance Method for Molecular hfs Spectroscopy: Measurements on 133Cs19F

Three sequential oscillatory fields are employed in a molecular beam electric resonance spectrometer in order to observe molecular hfs transitions which do not obey the criteria for observability in the usual beam apparatus. The triple resonance method has been used to examine the hfs of CsF under conditions of very weak external fields. The method shows considerable promise for the detailed study of molecular hfs when more than one nucleus has a quadrupole moment, and for the observation of transitions at audio frequencies between closely spaced molecular energy levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70906/2/JCPSA6-47-10-3904-1.pd

How children talk about events:Implications for eliciting and analyzing eyewitness reports

Legal and social service professionals often question whether various features of young witnesses’ responses during interviews are characteristic of children’s event reports or whether these features are concerning findings that reflect degraded memory, outside influence, or other phenomena. To assist helping professionals and researchers who collect data through interviews, we aggregated findings from child eyewitness studies and revisited transcript sets to construct fifteen principles that capture how children talk about events. These principles address children’s earliest event narratives, how children report information as interviews unfold and typical features of their narratives, threats to the accuracy of answers, the influence of interviewers’ language on children’s styles of reporting, how testimonies compare across multiple interviews and multiple witnesses to the same event, and the structure of accurate and inaccurate reports. A summary table highlights the implications of these principles for interviewers and the decision-makers who analyze children’s reports

The shape of motion perception: Global pooling of transformational apparent motion

Transformational apparent motion (TAM) is a visual phenomenon highlighting the utility of form information in motion processing. In TAM, smooth apparent motion is perceived when shapes in certain spatiotemporal arrangements change. It has been argued tha

Hyperfine Structure of Thallium Chloride

The radio‐frequency spectra of TlCl at very weak electric and magnetic fields have been measured with a molecular beam electric resonance spectrometer. From these spectra the hyperfine interaction constants for the four isotopic species of the molecule were calculated. The constants for 205Tl35Cl in the J  =  2,υ  =  0J=2,υ=0 state are: eqQ  =  − 15793.32(50)kHz,cCl  =  1.38(10)kHz,cTl  =  76.35(10)kHz,c3  =  − 0.13(10)kHz,c4  =  − 1.54(10)kHz.eqQ=−15793.32(50)kHz,cCl=1.38(10)kHz,cTl=76.35(10)kHz,c3=−0.13(10)kHz,c4=−1.54(10)kHz. A test was made for the polarization of the chlorine nucleus in the electric field of the molecule by comparing the ratio of the quadrupole interaction constants for 205Tl35Cl and 205Tl37Cl to the ratio of the quadrupole interaction constants for the free chlorine atoms. The agreement of the two ratios is within their uncertainties, thus providing no evidence for a polarization effect. In addition, the dependence of the spin–rotation and spin–spin interaction constants on isotope was found to show good agreement with theory.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69724/2/JCPSA6-50-5-2086-1.pd