Social change, migration and pregnancy intervals

Maternity histories from residents of a Pacific Island society, Tokelau, and migrants to New Zealand, are analysed using life table techniques. Inter-cohort differentials in patterns of family formation were found in the total Tokelau-origin population. The process of accelerated timing and spacing of pregnancies was more pronounced among migrants who tended to marry later, be pregnant at marriage, have shorter inter-pregnancy intervals at lower parities and to show evidence of family limitation occurring at higher parities. These results point to the significance of changing patterns of social control on strategies of family building

Sensing using differential surface plasmon ellipsometry

Copyright © 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 96 (2004) and may be found at http://link.aip.org/link/?JAPIAU/96/3004/1In this work a differential ellipsometric method utilizing surface plasmons (SPs) for monitoring refractive index changes, which could be used in chemical and biological sensors, is presented. The method is based upon determining the azimuth of elliptically polarized light reflected from a Kretschmann SP system, resulting from linearly polarized light containing both p and s components incident upon it. The sensitivity of this azimuth to the refractive index of a dielectric on the nonprism side of the metal film is demonstrated both experimentally and theoretically. The smallest refractive index change which is resolvable is of the order of 10–7 refractive index units, although it is believed that this could be improved upon were it not for experimental constraints due to atmospheric changes and vibrations. The method requires the Kretschmann configuration to be oriented at a fixed angle, and the SP to be excited at a fixed wavelength. With no moving parts this method would be particularly robust from an application point of view

Investigation of Integrated Twin Corner Reflectors Designed for 3-D InSAR Applications

There are potentially dangerous areas where InSAR technology cannot be applied routinely in the absence of proper persistent or distributed scatterers. Here, we planned and investigated the use of truncated trihedral triangle corner reflectors (CRs) oriented to ascending and descending directions for Sentinel-1 orbit, which were mounted on the optimal concrete basement including an additional global navigation satellite system (GNSS) adapter. These integrated benchmarks were designed to produce a signal-to-clutter ratio of about 100 (i.e., 20 dB). The mechanical design allows optimal orientation of the reflectors and resistance against dynamic effects. We investigated 1:5 models of the CRs and integrated benchmarks in an anechoic chamber to estimate the effects of truncation and the interference of the twin reflectors. The main effect of the interference is the asymmetric monostatic radar cross section, which can be neglected. The integrated benchmarks were also investigated in two recent landslide areas in Hungary using Sentinel-1 single look complex (SLC) scenes, which confirmed that the preliminary requirements can be met

The College News, 1936-04-08, Vol. 22, No. 19

Bryn Mawr College student newspaper. Merged with The Haverford News in 1968 to form the Bi-college News (with various titles from 1968 on). Published weekly (except holidays) during the academic year

Strongly coupled surface plasmons on thin shallow metallic gratings

Z. Chen, Ian R. Hooper, and J. Roy Sambles, Physical Review B, Vol. 77, article 161405(R) (2008). Copyright © 2008 by the American Physical Society.The optical response of a thin metallic film with shallow corrugations on both surfaces is explored and the structure is found to support a strongly coupled surface plasmon polariton when transverse magnetic radiation is incident in a plane parallel to the grating grooves. Modeling confirms that this strongly excited mode is the short range surface plasmon polariton and its presence is confirmed experimentally in the visible part of the spectrum

ASCA and contemporaneous ground-based observations of the BL Lacertae objects 1749+096 and 2200+420 (BL Lac)

We present ASCA observations of the radio-selected BL Lacertae objects 1749+096 (z=0.32) and 2200+420 (BL Lac, z=0.069) performed in 1995 Sept and Nov, respectively. The ASCA spectra of both sources can be described as a first approximation by a power law with photon index Gamma ~ 2. This is flatter than for most X-ray-selected BL Lacs observed with ASCA, in agreement with the predictions of current blazar unification models. While 1749+096 exhibits tentative evidence for spectral flattening at low energies, a concave continuum is detected for 2200+420: the steep low-energy component is consistent the high-energy tail of the synchrotron emission responsible for the longer wavelengths, while the harder tail at higher energies is the onset of the Compton component. The spectral energy distributions from radio to gamma-rays are consistent with synchrotron-self Compton emission from a single homogeneous region shortward of the IR/optical wavelengths, with a second component in the radio domain related to a more extended emission region. For 2200+420, comparing the 1995 Nov state with the optical/GeV flare of 1997 July, we find that models requiring inverse Compton scattering of external photons provide a viable mechanism for the production of the highest (GeV) energies during the flare. An increase of the external radiation density and of the power injected in the jet can reproduce the flat gamma-ray continuum observed in 1997 July. A directly testable prediction of this model is that the line luminosity in 2200+420 should vary shortly after (~1 month) a non-thermal synchrotron flare.Comment: 28 pages,6 figures, 5 tables; LaTeX document. accepted for publication in the Astrophysical Journa

Heterogeneity in tumor chromatin-doxorubicin binding revealed by in vivo fluorescence lifetime imaging confocal endomicroscopy

We present an approach to quantify drug-target engagement using in vivo fluorescence endomicroscopy, validated with in vitro measurements. Doxorubicin binding to chromatin changes the fluorescence lifetime of histone-GFP fusions that we measure in vivo at single-cell resolution using a confocal laparo/endomicroscope. We measure both intra- and inter-tumor heterogeneity in doxorubicin chromatin engagement in a model of peritoneal metastasis of ovarian cancer, revealing striking variation in the efficacy of doxorubicin-chromatin binding depending on intra-peritoneal or intravenous delivery. Further, we observe significant variations in doxorubicin-chromatin binding between different metastases in the same mouse and between different regions of the same metastasis. The quantitative nature of fluorescence lifetime imaging enables direct comparison of drug-target engagement for different drug delivery routes and between in vitro and in vivo experiments. This uncovers different rates of cell killing for the same level of doxorubicin binding in vitro and in vivo

Elastic Scattering and Direct Detection of Kaluza-Klein Dark Matter

Recently a new dark matter candidate has been proposed as a consequence of universal compact extra dimensions. It was found that to account for cosmological observations, the masses of the first Kaluza-Klein modes (and thus the approximate size of the extra dimension) should be in the range 600-1200 GeV when the lightest Kaluza-Klein particle (LKP) corresponds to the hypercharge boson and in the range 1 - 1.8 TeV when it corresponds to a neutrino. In this article, we compute the elastic scattering cross sections between Kaluza-Klein dark matter and nuclei both when the lightest Kaluza-Klein particle is a KK mode of a weak gauge boson, and when it is a neutrino. We include nuclear form factor effects which are important to take into account due to the large LKP masses favored by estimates of the relic density. We present both differential and integrated rates for present and proposed Germanium, NaI and Xenon detectors. Observable rates at current detectors are typically less than one event per year, but the next generation of detectors can probe a significant fraction of the relevant parameter space.Comment: 23 pages, 11 figures; v2,v3: Ref. added, discussion improved, conclusions unchanged. v4: Introduction was expanded to be more appropriate for non experts. Various clarifications added in the text. Version to be published in New Journal of Physic

Two photon annihilation of Kaluza-Klein dark matter

We investigate the fermionic one-loop cross section for the two photon annihilation of Kaluza-Klein (KK) dark matter particles in a model of universal extra dimensions (UED). This process gives a nearly mono-energetic gamma-ray line with energy equal to the KK dark matter particle mass. We find that the cross section is large enough that if a continuum signature is detected, the energy distribution of gamma-rays should end at the particle mass with a peak that is visible for an energy resolution of the detector at the percent level. This would give an unmistakable signature of a dark matter origin of the gamma-rays, and a unique determination of the dark matter particle mass, which in the case studied should be around 800 GeV. Unlike the situation for supersymmetric models where the two-gamma peak may or may not be visible depending on parameters, this feature seems to be quite robust in UED models, and should be similar in other models where annihilation into fermions is not helicity suppressed. The observability of the signal still depends on largely unknown astrophysical parameters related to the structure of the dark matter halo. If the dark matter near the galactic center is adiabatically contracted by the central star cluster, or if the dark matter halo has substructure surviving tidal effects, prospects for detection look promising.Comment: 17 pages, 3 figures; slightly revised versio

Host galaxies of luminous quasars: population synthesis of optical off-axis spectra

There is increasing evidence of a connection between AGN activity and galaxy evolution. To obtain further insight into this potentially important evolutionary phase, we analyse the properties of quasar host galaxies. In this paper, we present a population synthesis modeling technique for off-axis spectra, the results of which constrain host colour and the stellar ages of luminous quasars (M_V(nuc)<-23). Our technique is similar to well established quiescent-galaxy models, modified to accommodate scattered nuclear light (a combination of atmospheric, instrumental and host galaxy scattered light) observed off axis. In our model, subtraction of residual scattered quasar light is performed, while simultaneously modeling the constituent stellar populations of the host galaxy. The reliability of this technique is tested via a Monte-Carlo routine in which the correspondence between synthetic spectra with known parameters and the model output is determined. Application of this model to a preliminary sample of 10 objects is presented and compared to previous studies. Spectroscopic data was obtained via long-slit and integral-field unit observations on the Keck and WIYN telescopes. We confirm that elliptical quasar hosts are distinguishable (bluer) from inactive ellipticals in rest frame B-V colour. Additionally, we note a trend for radio luminous (L_5GHz > 10^40 erg s^-1) quasars to be located in redder host galaxies in comparison to their less luminous radio counterparts. While the host colour and age of our radio luminous sample is in close proximity to the green valley, our radio faint sample is consistent with quiescent star-forming galaxies. However, further observations are needed to confirm these results. Finally, we discuss future applications for our technique on a larger sample of objects being obtained via SALT and WIYN telescope observing campaigns.Comment: 18 pages, 10 figures, accepted for publication in MNRA