WorldWideScience

Sample records for strong lensing effects

  1. SUNYAEV-ZEL'DOVICH EFFECT OBSERVATIONS OF STRONG LENSING GALAXY CLUSTERS: PROBING THE OVERCONCENTRATION PROBLEM

    International Nuclear Information System (INIS)

    Gralla, Megan B.; Gladders, Michael D.; Marrone, Daniel P.; Bayliss, Matthew; Carlstrom, John E.; Greer, Christopher; Hennessy, Ryan; Koester, Benjamin; Leitch, Erik; Sharon, Keren; Barrientos, L. Felipe; Bonamente, Massimiliano; Bulbul, Esra; Hasler, Nicole; Culverhouse, Thomas; Hawkins, David; Lamb, James; Gilbank, David G.; Joy, Marshall; Miller, Amber

    2011-01-01

    We have measured the Sunyaev-Zel'dovich (SZ) effect for a sample of 10 strong lensing selected galaxy clusters using the Sunyaev-Zel'dovich Array (SZA). The SZA is sensitive to structures on spatial scales of a few arcminutes, while the strong lensing mass modeling constrains the mass at small scales (typically <30''). Combining the two provides information about the projected concentrations of the strong lensing clusters. The Einstein radii we measure are twice as large as expected given the masses inferred from SZ scaling relations. A Monte Carlo simulation indicates that a sample randomly drawn from the expected distribution would have a larger median Einstein radius than the observed clusters about 3% of the time. The implied overconcentration has been noted in previous studies and persists for this sample, even when we take into account that we are selecting large Einstein radius systems, suggesting that the theoretical models still do not fully describe the observed properties of strong lensing clusters.

  2. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies......, but it is based on well understood physics and unlike distance ladder methods there are no calibration issues. Moreover, it has an advantage over some of the leading methods (such as Type Ia SNe) in that it is a purely cosmological approach. In this thesis, the property of strong gravitational lensing - time...

  3. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  4. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown......One of the most intriguing recent results in physics is the growing evidence that an unknown energy field and an unknown kind of matter are the major components of the Universe (70% and 30%, respectively; see e.g. Riess et al. 1998, Spergel et al. 2007). Understanding and estimating the precise...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies...

  5. Shadows and strong gravitational lensing: a brief review

    Science.gov (United States)

    Cunha, Pedro V. P.; Herdeiro, Carlos A. R.

    2018-04-01

    For ultra compact objects, light rings and fundamental photon orbits (FPOs) play a pivotal role in the theoretical analysis of strong gravitational lensing effects, and of BH shadows in particular. In this short review, specific models are considered to illustrate how FPOs can be useful in order to understand some non-trivial gravitational lensing effects. This paper aims at briefly overviewing the theoretical foundations of these effects, touching also some of the related phenomenology, both in general relativity and alternative theories of gravity, hopefully providing some intuition and new insights for the underlying physics, which might be critical when testing the Kerr black hole hypothesis.

  6. Strong Gravitational Lensing in a Brane-World Black Hole

    Science.gov (United States)

    Li, GuoPing; Cao, Biao; Feng, Zhongwen; Zu, Xiaotao

    2015-09-01

    Adopting the strong field limit approach, we investigated the strong gravitational lensing in a Brane-World black hole, which means that the strong field limit coefficients and the deflection angle in this gravitational field are obtained. With this result, it can be said with certainly that the strong gravitational lensing is related to the metric of gravitational fields closely, the cosmology parameter α and the dark matter parameter β come from the Brane-World black hole exerts a great influence on it. Comparing with the Schwarzschild-AdS spacetime and the Schwarzschild-XCMD spacetime, the parameters α, β of black holes have the similar effects on the gravitational lensing. In some way, we infer that the real gravitational fields in our universe can be described by this metric, so the results of the strong gravitational lensing in this spacetime will be more reasonable for us to observe. Finally, it has to be noticed that the influence which the parameters α, β exerted on the main observable quantities of this gravitational field is discussed.

  7. Strong lensing of gravitational waves as seen by LISA.

    Science.gov (United States)

    Sereno, M; Sesana, A; Bleuler, A; Jetzer, Ph; Volonteri, M; Begelman, M C

    2010-12-17

    We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).

  8. Using Strong Gravitational Lensing to Identify Fossil Group Progenitors

    Science.gov (United States)

    Johnson, Lucas E.; Irwin, Jimmy A.; White, Raymond E., III; Wong, Ka-Wah; Maksym, W. Peter; Dupke, Renato A.; Miller, Eric D.; Carrasco, Eleazar R.

    2018-04-01

    Fossil galaxy systems are classically thought to be the end result of galaxy group/cluster evolution, as galaxies experiencing dynamical friction sink to the center of the group potential and merge into a single, giant elliptical that dominates the rest of the members in both mass and luminosity. Most fossil systems discovered lie within z fossil criteria within the look forward time. Since strong gravitational lensing preferentially selects groups merging along the line of sight, or systems with a high mass concentration like fossil systems, we searched the CASSOWARY survey of strong-lensing events with the goal of determining whether lensing systems have any predisposition to being fossil systems or progenitors. We find that ∼13% of lensing groups are identified as traditional fossils while only ∼3% of nonlensing control groups are. We also find that ∼23% of lensing systems are traditional fossil progenitors compared to ∼17% for the control sample. Our findings show that strong-lensing systems are more likely to be fossil/pre-fossil systems than comparable nonlensing systems. Cumulative galaxy luminosity functions of the lensing and nonlensing groups also indicate a possible, fundamental difference between strong-lensing and nonlensing systems’ galaxy populations, with lensing systems housing a greater number of bright galaxies even in the outskirts of groups.

  9. A dearth of dark matter in strong gravitational lenses

    NARCIS (Netherlands)

    Sanders, R. H.

    I show that the lensing masses of the Sloan Lens Advanced Camera Surveys sample of strong gravitational lenses are consistent with the stellar masses determined from population synthesis models using the Salpeter initial mass function. This is true in the context of both General Relativity and

  10. Strong lensing by fermionic dark matter in galaxies

    Science.gov (United States)

    Gómez, L. Gabriel; Argüelles, C. R.; Perlick, Volker; Rueda, J. A.; Ruffini, R.

    2016-12-01

    It has been shown that a self-gravitating system of massive keV fermions in thermodynamic equilibrium correctly describes the dark matter (DM) distribution in galactic halos (from dwarf to spiral and elliptical galaxies) and that, at the same time, it predicts a denser quantum core towards the center of the configuration. Such a quantum core, for a fermion mass in the range of 50 keV ≲m c2≲345 keV , can be an alternative interpretation of the central compact object in Sgr A*, traditionally assumed to be a black hole (BH). We present in this work the gravitational lensing properties of this novel DM configuration in nearby Milky-Way-like spiral galaxies. We describe the lensing effects of the pure DM component both on halo scales, where we compare them to the effects of the Navarro-Frenk-White and the nonsingular isothermal sphere DM models, and near the galaxy center, where we compare them with the effects of a Schwarzschild BH. For the particle mass leading to the most compact DM core, m c2≈1 02 keV , we draw the following conclusions. At distances r ≳20 pc from the center of the lens the effect of the central object on the lensing properties is negligible. However, we show that measurements of the deflection angle produced by the DM distribution in the outer region at a few kpc, together with rotation curve data, could help to discriminate between different DM models. In the inner regions 1 0-6≲r ≲20 pc , the lensing effects of a DM quantum core alternative to the BH scenario becomes a theme of an analysis of unprecedented precision which is challenging for current technological developments. We show that at distances ˜1 0-4 pc strong lensing effects, such as multiple images and Einstein rings, may occur. Large differences in the deflection angle produced by a DM central core and a central BH appear at distances r ≲1 0-6 pc ; in this regime the weak-field formalism is no longer applicable and the exact general-relativistic formula has to be used

  11. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  12. Galaxy number counts and implications for strong lensing

    NARCIS (Netherlands)

    Fassnacht, C. D.; Koopmans, L. V. E.; Wong, K. C.

    We compare galaxy number counts in Advanced Camera for Surveys (ACS) fields containing moderate-redshift (0.2 strong gravitational lenses with those in two control samples: (1) the first square degree of the COSMOS survey, comprising 259 ACS fields and (2) 20 ‘pure-parallel’ fields randomly

  13. Cosmological tests with strong gravitational lenses using Gaussian processes

    Science.gov (United States)

    Yennapureddy, Manoj K.; Melia, Fulvio

    2018-03-01

    Strong gravitational lenses provide source/lens distance ratios D_{obs} useful in cosmological tests. Previously, a catalog of 69 such systems was used in a one-on-one comparison between the standard model, Λ CDM, and the Rh=ct universe, which has thus far been favored by the application of model selection tools to many other kinds of data. But in that work, the use of model parametric fits to the observations could not easily distinguish between these two cosmologies, in part due to the limited measurement precision. Here, we instead use recently developed methods based on Gaussian Processes (GP), in which D_{obs} may be reconstructed directly from the data without assuming any parametric form. This approach not only smooths out the reconstructed function representing the data, but also reduces the size of the 1σ confidence regions, thereby providing greater power to discern between different models. With the current sample size, we show that analyzing strong lenses with a GP approach can definitely improve the model comparisons, producing probability differences in the range ˜ 10-30%. These results are still marginal, however, given the relatively small sample. Nonetheless, we conclude that the probability of Rh=ct being the correct cosmology is somewhat higher than that of Λ CDM, with a degree of significance that grows with the number of sources in the subsamples we consider. Future surveys will significantly grow the catalog of strong lenses and will therefore benefit considerably from the GP method we describe here. In addition, we point out that if the Rh=ct universe is eventually shown to be the correct cosmology, the lack of free parameters in the study of strong lenses should provide a remarkably powerful tool for uncovering the mass structure in lensing galaxies.

  14. How to Measure Dark Energy with LSST's Strong Gravitational Lenses

    Science.gov (United States)

    Marshall, Philip J.; Treu, T.; Brunner, R. J.; Strong Lensing, LSST; Dark Energy Science Collaborations

    2013-01-01

    Strong gravitational lensing is sensitive to dark energy (DE) via the combinations of angular diameter distances that appear in model predictions of the lens strength. Lenses with variable sources offer the most promise: the corresponding time delay distance has recently been shown to be measurable to 5% precision. Large samples of lensed quasars and supernovae will allow internal degeneracy-breaking and so enable the most direct access to the DE parameters, while multiple source-plane, compound lens systems may provide an alternative, complementary, H0-free probe. Its wide field survey and high cadence will enable LSST to provide a sample of several thousand measured time delays, two orders of magnitude larger than the current sample, and allow an independent, competitive Stage IV DE parameter measurement to be made. However, practical problems to be solved include: lens detection (which may be very sensitive to image quality and deblender performance); image and lightcurve modelling (which could be both CPU and manual labor-intensive); obtaining and analyzing high resolution spectro-imaging follow-up data; and interpreting the whole sample of lenses in the context of the well-studied subset.

  15. Meso-Structure in Three Strong-lensing Systems

    Science.gov (United States)

    Saha, Prasenjit; Williams, Liliya L. R.; Ferreras, Ignacio

    2007-07-01

    We map substructure in three strong-lensing systems having particularly good image data: the galaxy lens MG J0414+053 and the clusters SDSS J1004+411 and ACO 1689. Our method is to first reconstruct the lens as a pixelated mass map and then subtract off the symmetric part (in the galaxy case) or a projected Navarro-Frenk-White profile (for the cluster lenses). In all three systems we find extended irregular structures, or meso-structures, having of order 10% of the total mass. In J0414+053, the meso-structure suggests a tidal tail connecting the main lens with a nearby galaxy; however, this interpretation is tentative. In the clusters, the identification of meso-structure is more secure, especially in ACO 1689, where two independent sets of lensed images imply very similar meso-structure. In all three cases, the meso-structures are correlated with galaxies but much more extended and massive than the stellar components of single galaxies. Such extended structures cannot plausibly persist in such high-density regions without being mixed; the crossing times are too short. The meso-structures therefore appear to be merging or otherwise dynamically evolving systems.

  16. Strong Lensing Science Results from the Hyper Suprime-Cam Survey

    Science.gov (United States)

    Wong, Kenneth; HSC SSP Strong Lens Working Group

    2018-01-01

    Strong gravitational lenses are valuable objects for studying galaxy structure and cosmology. Lensing is a unique probe of the dark matter structure of galaxies, groups, and clusters, as well as an independent tool for constraining cosmological parameters. Lensing also magnifies the background source population, allowing for detailed studies of their properties at high resolution. However, strong lenses are rare and difficult to find, requiring deep wide-area high-resolution imaging surveys. With data from the ongoing Hyper Suprime-Cam (HSC) Subaru Strategic Program, we have discovered over 100 new strong lenses at the galaxy and group scale to expand the sample of lensing systems, particularly at redshifts z > 0.5, where there have previously been relatively few known lenses. We present a summary of the latest strong lensing science results from the HSC survey data taken through the S17A semester.

  17. Simulation-based marginal likelihood for cluster strong lensing cosmology

    Science.gov (United States)

    Killedar, M.; Borgani, S.; Fabjan, D.; Dolag, K.; Granato, G.; Meneghetti, M.; Planelles, S.; Ragone-Figueroa, C.

    2018-01-01

    Comparisons between observed and predicted strong lensing properties of galaxy clusters have been routinely used to claim either tension or consistency with Λ cold dark matter cosmology. However, standard approaches to such cosmological tests are unable to quantify the preference for one cosmology over another. We advocate approximating the relevant Bayes factor using a marginal likelihood that is based on the following summary statistic: the posterior probability distribution function for the parameters of the scaling relation between Einstein radii and cluster mass, α and β. We demonstrate, for the first time, a method of estimating the marginal likelihood using the X-ray selected z > 0.5 Massive Cluster Survey clusters as a case in point and employing both N-body and hydrodynamic simulations of clusters. We investigate the uncertainty in this estimate and consequential ability to compare competing cosmologies, which arises from incomplete descriptions of baryonic processes, discrepancies in cluster selection criteria, redshift distribution and dynamical state. The relation between triaxial cluster masses at various overdensities provides a promising alternative to the strong lensing test.

  18. Cusp-core problem and strong gravitational lensing

    International Nuclear Information System (INIS)

    Li Nan; Chen Daming

    2009-01-01

    Cosmological numerical simulations of galaxy formation have led to the cuspy density profile of a pure cold dark matter halo toward the center, which is in sharp contradiction with the observations of the rotation curves of cold dark matter-dominated dwarf and low surface brightness disk galaxies, with the latter tending to favor mass profiles with a flat central core. Many efforts have been devoted to resolving this cusp-core problem in recent years, among them, baryon-cold dark matter interactions are considered to be the main physical mechanisms erasing the cold dark matter (CDM) cusp into a flat core in the centers of all CDM halos. Clearly, baryon-cold dark matter interactions are not customized only for CDM-dominated disk galaxies, but for all types, including giant ellipticals. We first fit the most recent high resolution observations of rotation curves with the Burkert profile, then use the constrained core size-halo mass relation to calculate the lensing frequency, and compare the predicted results with strong lensing observations. Unfortunately, it turns out that the core size constrained from rotation curves of disk galaxies cannot be extrapolated to giant ellipticals. We conclude that, in the standard cosmological paradigm, baryon-cold dark matter interactions are not universal mechanisms for galaxy formation, and therefore, they cannot be true solutions to the cusp-core problem.

  19. A Robust Mass Estimator for Dark Matter Subhalo Perturbations in Strong Gravitational Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Minor, Quinn E. [Department of Science, Borough of Manhattan Community College, City University of New York, New York, NY 10007 (United States); Kaplinghat, Manoj [Department of Physics and Astronomy, University of California, Irvine CA 92697 (United States); Li, Nan [Department of Astronomy and Astrophysics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)

    2017-08-20

    A few dark matter substructures have recently been detected in strong gravitational lenses through their perturbations of highly magnified images. We derive a characteristic scale for lensing perturbations and show that they are significantly larger than the perturber’s Einstein radius. We show that the perturber’s projected mass enclosed within this radius, scaled by the log-slope of the host galaxy’s density profile, can be robustly inferred even if the inferred density profile and tidal radius of the perturber are biased. We demonstrate the validity of our analytic derivation using several gravitational lens simulations where the tidal radii and the inner log-slopes of the density profile of the perturbing subhalo are allowed to vary. By modeling these simulated data, we find that our mass estimator, which we call the effective subhalo lensing mass, is accurate to within about 10% or smaller in each case, whereas the inferred total subhalo mass can potentially be biased by nearly an order of magnitude. We therefore recommend that the effective subhalo lensing mass be reported in future lensing reconstructions, as this will allow for a more accurate comparison with the results of dark matter simulations.

  20. Power spectrum of dark matter substructure in strong gravitational lenses

    Science.gov (United States)

    Diaz Rivero, Ana; Cyr-Racine, Francis-Yan; Dvorkin, Cora

    2018-01-01

    Studying the smallest self-bound dark matter structure in our Universe can yield important clues about the fundamental particle nature of dark matter. Galaxy-scale strong gravitational lensing provides a unique way to detect and characterize dark matter substructures at cosmological distances from the Milky Way. Within the cold dark matter (CDM) paradigm, the number of low-mass subhalos within lens galaxies is expected to be large, implying that their contribution to the lensing convergence field is approximately Gaussian and could thus be described by their power spectrum. We develop here a general formalism to compute from first principles the substructure convergence power spectrum for different populations of dark matter subhalos. As an example, we apply our framework to two distinct subhalo populations: a truncated Navarro-Frenk-White subhalo population motivated by standard CDM, and a truncated cored subhalo population motivated by self-interacting dark matter (SIDM). We study in detail how the subhalo abundance, mass function, internal density profile, and concentration affect the amplitude and shape of the substructure power spectrum. We determine that the power spectrum is mostly sensitive to a specific combination of the subhalo abundance and moments of the mass function, as well as to the average tidal truncation scale of the largest subhalos included in the analysis. Interestingly, we show that the asymptotic slope of the substructure power spectrum at large wave number reflects the internal density profile of the subhalos. In particular, the SIDM power spectrum exhibits a characteristic steepening at large wave number absent in the CDM power spectrum, opening the possibility of using this observable, if at all measurable, to discern between these two scenarios.

  1. Strong gravitational lensing by a charged Kiselev black hole

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Ainou, Mustapha [Baskent University, Engineering Faculty, Ankara (Turkey); Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom); Jamil, Mubasher [National University of Sciences and Technology (NUST), Department of Mathematics, School of Natural Sciences (SNS), Islamabad (Pakistan)

    2017-06-15

    We study the gravitational lensing scenario where the lens is a spherically symmetric charged black hole (BH) surrounded by quintessence matter. The null geodesic equations in the curved background of the black hole are derived. The resulting trajectory equation is solved analytically via perturbation and series methods for a special choice of parameters, and the distance of the closest approach to black hole is calculated. We also derive the lens equation giving the bending angle of light in the curved background. In the strong field approximation, the solution of the lens equation is also obtained for all values of the quintessence parameter w{sub q}. For all w{sub q}, we show that there are no stable closed null orbits and that corrections to the deflection angle for the Reissner-Nordstroem black hole when the observer and the source are at large, but finite, distances from the lens do not depend on the charge up to the inverse of the distances squared. A part of the present work, analyzed, however, with a different approach, is the extension of Younas et al. (Phys Rev D 92:084042, 2015) where the uncharged case has been treated. (orig.)

  2. Mapping the distribution of luminous and dark matter in strong lensing galaxies

    OpenAIRE

    Ferreras, I.; Saha, P.; Williams, L. L. R.; Burles, S.

    2007-01-01

    We present the distribution of luminous and dark matter in a set of strong lensing (early-type) galaxies. By combining two independent techniques – stellar population synthesis and gravitational lensing – we can compare the baryonic and dark matter content in these galaxies within the regions that can be probed using the images of the lensed background source. Two samples were studied, extracted from the CASTLES and SLACS surveys. The former probes a wider range of redshifts and allows us to ...

  3. The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Andrew B. [The Observatories of the Carnegie Institution for Science, Pasadena, CA (United States); Smith, Russell J. [Centre for Extragalactic Astronomy, University of Durham, South Road, Durham (United Kingdom); Conroy, Charlie [Department of Astronomy, Harvard University, Cambridge, MA (United States); Villaume, Alexa [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); Van Dokkum, Pieter, E-mail: anewman@obs.carnegiescience.edu [Department of Astrophysical Sciences, Yale University, New Haven, CT (United States)

    2017-08-20

    We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high- σ ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M {sub *}/ L using lensing and stellar dynamics. We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy and van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2–3 σ tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08 M {sub ⊙}. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to <2 σ . There is moderate evidence for a reduced number of low-mass stars in the SNELLS spectra, but no such evidence in a composite spectrum of matched- σ ETGs drawn from the SDSS. Such variation in the form of the IMF at low stellar masses ( m ≲ 0.3 M {sub ⊙}), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M {sub *}/ L relative to the mean matched- σ ETG. We provide the spectra used in this study to facilitate future comparisons.

  4. Algorithms and Programs for Strong Gravitational Lensing In Kerr Space-time Including Polarization

    Science.gov (United States)

    Chen, Bin; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie; Maddumage, Prasad

    2015-05-01

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.

  5. ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION

    International Nuclear Information System (INIS)

    Chen, Bin; Maddumage, Prasad; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie

    2015-01-01

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python

  6. GALAXY SCALE LENSES IN THE RCS2. I. FIRST CATALOG OF CANDIDATE STRONG LENSES

    International Nuclear Information System (INIS)

    Anguita, T.; Barrientos, L. F.; Gladders, M. D.; Faure, C.; Yee, H. K. C.; Gilbank, D. G.

    2012-01-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey. The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 ∼ 11 [M ☉ h –1 ]) and rich in dark matter (M/L-bar∼ 14 [M ☉ /L ☉,B h]). Even though a slight increasing trend in the mass-to-light ratio is observed from z = 0.2 to z = 0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  7. GALAXY SCALE LENSES IN THE RCS2. I. FIRST CATALOG OF CANDIDATE STRONG LENSES

    Energy Technology Data Exchange (ETDEWEB)

    Anguita, T. [Centro de Astro-Ingenieria, Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Barrientos, L. F. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Gladders, M. D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Faure, C. [Laboratoire d' Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Obervatoire de Sauverny, CH-1290 Versoix (Switzerland); Yee, H. K. C.; Gilbank, D. G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St George Street, Toronto, Ontario, M5S 3H4 (Canada)

    2012-04-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey. The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 {approx}< z {approx}< 0.5 surrounded by blue arcs or apparent multiple images of background sources. The catalog is a valuable complement to previous galaxy-galaxy lens catalogs as it samples an intermediate lens redshift range and is composed of bright sources and lenses that allow easy follow-up for detailed analysis. Mass and mass-to-light ratio estimates reveal that the lens galaxies are massive ( M-bar {approx} 5.5 Multiplication-Sign 10{sup 11} [M{sub Sun} h{sup -1}]) and rich in dark matter (M/L-bar{approx} 14 [M{sub Sun }/L{sub Sun ,B} h]). Even though a slight increasing trend in the mass-to-light ratio is observed from z = 0.2 to z = 0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  8. Dark matter distributions in early-type galaxies from strong gravitational lensing

    International Nuclear Information System (INIS)

    Eichner, Thomas Martin

    2013-01-01

    Dark matter constitutes a large fraction of the mass of early-type galaxies. However, the exact amount and spatial distribution of the dark matter, especially in the galaxies' center is still unclear. Furthermore, galaxies in dense environments such as the centers of galaxy clusters shrink in size, since parts of their outer dark matter halo is stripped away. The aim of this thesis is to measure the dark matter content in the centers and outskirts of elliptical galaxies by analyzing the strong gravitational lensing effect they produce. Gravitational lensing is well-suited for investigating dark matter, since it is sensitive to all forms of matter, regardless of its dynamical or evolutionary state. We present gravitational lensing studies of the exceptional strong lensing systems SDSS J1538+5817 and SDSS J1430+4105, identified by the Sloan Lens ACS survey. The lenses are elliptical galaxies at z l =0.143 and z l =0.285, respectively. For SDSS J1538+5817 we show that both multiple imaged sources are located at the same redshift z s =0.531. Its multiple images span a range from 1 to 4 kpc in the plane of the lens. For SDSS J1430+4105, the source at redshift z s =0.575 is imaged into a broad Einstein ring, covering radii from 4 kpc to 10 kpc in the plane of the lens. In both cases, the lensed images can be accurately and consistently reproduced with different modeling approaches. We get projected total masses of 8.11 +0.27 -0.59 x 10 10 M s un within the Einstein radius of 2.5 kpc for SDSS J1538+5817 and 5.37±0.06 x 10 11 M s un within 6.5 kpc for SDSS J1430+4105. The luminous and dark matter were traced separately, resulting in dark matter fractions within the Einstein radius of 0.1 +0.2 -0.1 and 0.40 +0.14 -0.10 for SDSS J1538+5817 and SDSS J1430+4105, respectively. We assume a de Vaucouleurs profile to trace the light distribution of both galaxies. From the stellar mass associated with this light, we can explicitly derive a stellar mass-to-light ratio of (M de

  9. GEMINI/GMOS SPECTROSCOPY OF 26 STRONG-LENSING-SELECTED GALAXY CLUSTER CORES

    International Nuclear Information System (INIS)

    Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon; Oguri, Masamune

    2011-01-01

    We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS) and the Second Red-Sequence Cluster Survey (RCS-2). The 26 galaxy cluster lenses span a redshift range of 0.2 Vir = 7.84 x 10 14 M sun h -1 0.7 , which is somewhat higher than predictions for strong-lensing-selected clusters in simulations. The disagreement is not significant considering the large uncertainty in our dynamical data, systematic uncertainties in the velocity dispersion calibration, and limitations of the theoretical modeling. Nevertheless our study represents an important first step toward characterizing large samples of clusters that are identified in a systematic way as systems exhibiting dramatic strong-lensing features.

  10. Strongly lensed gravitational waves and electromagnetic signals as powerful cosmic rulers

    Science.gov (United States)

    Wei, Jun-Jie; Wu, Xue-Feng

    2017-12-01

    In this paper, we discuss the possibility of using strongly lensed gravitational waves (GWs) and their electromagnetic (EM) counterparts as powerful cosmic rulers. In the EM domain, it has been suggested that joint observations of the time delay (Δτ) between lensed quasar images and the velocity dispersion (σ) of the lensing galaxy (i.e. the combination Δτ/σ2) are able to constrain the cosmological parameters more strongly than Δτ or σ2 separately. Here, for the first time, we propose that this Δτ/σ2 method can be applied to the strongly lensed systems observed in both GW and EM windows. Combining the redshifts, images and σ observed in the EM domain with the very precise Δτ derived from lensed GW signals, we expect that accurate multimessenger cosmology can be achieved in the era of third-generation GW detectors. Comparing with the constraints from the Δτ method, we prove that using Δτ/σ2 can improve the discrimination between cosmological models. Furthermore, we demonstrate that with ∼50 strongly lensed GW-EM systems, we can reach a constraint on the dark energy equation of state w comparable to the 580 Union2.1 Type Ia supernovae data. Much more stringent constraints on w can be obtained when combining the Δτ and Δτ/σ2 methods.

  11. The detection of a population of submillimeter-bright, strongly lensed galaxies.

    Science.gov (United States)

    Negrello, Mattia; Hopwood, R; De Zotti, G; Cooray, A; Verma, A; Bock, J; Frayer, D T; Gurwell, M A; Omont, A; Neri, R; Dannerbauer, H; Leeuw, L L; Barton, E; Cooke, J; Kim, S; da Cunha, E; Rodighiero, G; Cox, P; Bonfield, D G; Jarvis, M J; Serjeant, S; Ivison, R J; Dye, S; Aretxaga, I; Hughes, D H; Ibar, E; Bertoldi, F; Valtchanov, I; Eales, S; Dunne, L; Driver, S P; Auld, R; Buttiglione, S; Cava, A; Grady, C A; Clements, D L; Dariush, A; Fritz, J; Hill, D; Hornbeck, J B; Kelvin, L; Lagache, G; Lopez-Caniego, M; Gonzalez-Nuevo, J; Maddox, S; Pascale, E; Pohlen, M; Rigby, E E; Robotham, A; Simpson, C; Smith, D J B; Temi, P; Thompson, M A; Woodgate, B E; York, D G; Aguirre, J E; Beelen, A; Blain, A; Baker, A J; Birkinshaw, M; Blundell, R; Bradford, C M; Burgarella, D; Danese, L; Dunlop, J S; Fleuren, S; Glenn, J; Harris, A I; Kamenetzky, J; Lupu, R E; Maddalena, R J; Madore, B F; Maloney, P R; Matsuhara, H; Michaowski, M J; Murphy, E J; Naylor, B J; Nguyen, H; Popescu, C; Rawlings, S; Rigopoulou, D; Scott, D; Scott, K S; Seibert, M; Smail, I; Tuffs, R J; Vieira, J D; van der Werf, P P; Zmuidzinas, J

    2010-11-05

    Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.

  12. Finding strong gravitational lenses in the Kilo Degree Survey with Convolutional Neural Networks

    Science.gov (United States)

    Petrillo, C. E.; Tortora, C.; Chatterjee, S.; Vernardos, G.; Koopmans, L. V. E.; Verdoes Kleijn, G.; Napolitano, N. R.; Covone, G.; Schneider, P.; Grado, A.; McFarland, J.

    2017-11-01

    The volume of data that will be produced by new-generation surveys requires automatic classification methods to select and analyse sources. Indeed, this is the case for the search for strong gravitational lenses, where the population of the detectable lensed sources is only a very small fraction of the full source population. We apply for the first time a morphological classification method based on a Convolutional Neural Network (CNN) for recognizing strong gravitational lenses in 255 deg2 of the Kilo Degree Survey (KiDS), one of the current-generation optical wide surveys. The CNN is currently optimized to recognize lenses with Einstein radii ≳1.4 arcsec, about twice the r-band seeing in KiDS. In a sample of 21 789 colour-magnitude selected luminous red galaxies (LRGs), of which three are known lenses, the CNN retrieves 761 strong-lens candidates and correctly classifies two out of three of the known lenses. The misclassified lens has an Einstein radius below the range on which the algorithm is trained. We down-select the most reliable 56 candidates by a joint visual inspection. This final sample is presented and discussed. A conservative estimate based on our results shows that with our proposed method it should be possible to find ∼100 massive LRG-galaxy lenses at z ≲ 0.4 in KiDS when completed. In the most optimistic scenario, this number can grow considerably (to maximally ∼2400 lenses), when widening the colour-magnitude selection and training the CNN to recognize smaller image-separation lens systems.

  13. Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals.

    Science.gov (United States)

    Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong

    2017-03-03

    We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 10^{4}  s. This uncertainty can be suppressed by a factor of ∼10^{10}, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ-ray bursts and fast radio bursts.

  14. CLASH: Extending galaxy strong lensing to small physical scales with distant sources highly magnified by galaxy cluster members

    International Nuclear Information System (INIS)

    Grillo, C.; Christensen, L.; Gobat, R.; Presotto, V.; Balestra, I.; Nonino, M.; Biviano, A.; Mercurio, A.; Rosati, P.; Vanzella, E.; Graves, G.; Lemze, D.; Ford, H.; Bartelmann, M.; Benitez, N.; Bouwens, R.; Bradley, L.; Coe, D.; Broadhurst, T.; Donahue, M.

    2014-01-01

    We present a complex strong lensing system in which a double source is imaged five times by two early-type galaxies. We take advantage in this target of the extraordinary multi-band photometric data set obtained as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, complemented by the spectroscopic measurements of the VLT/VIMOS and FORS2 follow-up campaign. We use a photometric redshift value of 3.7 for the source and confirm spectroscopically the membership of the two lenses to the galaxy cluster MACS J1206.2–0847 at redshift 0.44. We exploit the excellent angular resolution of the HST/ACS images to model the two lenses in terms of singular isothermal sphere profiles and derive robust effective velocity dispersion values of 97 ± 3 and 240 ± 6 km s –1 . Interestingly, the total mass distribution of the cluster is also well characterized by using only the local information contained in this lensing system, which is located at a projected distance of more than 300 kpc from the cluster luminosity center. According to our best-fitting lensing and composite stellar population models, the source is magnified by a total factor of 50 and has a luminous mass of approximately (1.0 ± 0.5) × 10 9 M ☉ (assuming a Salpeter stellar initial mass function). By combining the total and luminous mass estimates of the two lenses, we measure luminous over total mass fractions projected within the effective radii of 0.51 ± 0.21 and 0.80 ± 0.32. Remarkably, with these lenses we can extend the analysis of the mass properties of lens early-type galaxies by factors that are approximately two and three times smaller than previously done with regard to, respectively, velocity dispersion and luminous mass. The comparison of the total and luminous quantities of our lenses with those of astrophysical objects with different physical scales, like massive early-type galaxies and dwarf spheroidals, reveals the potential of studies of this kind for improving our

  15. Radio and Gamma-Ray Monitoring of Strongly Lensed Quasars and Blazars

    NARCIS (Netherlands)

    Rumbaugh, Nick; Fassnacht, Chris; McKean, John; Koopmans, Leon; Auger, Matthew; Suyu, Sherry; Marshall, Philip J.

    2015-01-01

    We observed six strongly lensed, radio-loud quasars (MG 0414+0534, CLASS B0712+472, JVAS B1030+074, CLASS B1127+385, CLASS B1152+199, and JVAS B1938+666) in order to identify systems suitable for measuring cosmological parameters using time delays between their multiple images. Two separate

  16. Investigating the internal structure of galaxies and clusters through strong gravitational lensing

    Science.gov (United States)

    Jigish Gandhi, Pratik; Grillo, Claudio; Bonamigo, Mario

    2018-01-01

    Gravitational lensing studies have radically improved our understanding of the internal structure of galaxies and cluster-scale systems. In particular, the combination of strong lensing and stellar dynamics or stellar population synthesis models have made it possible to characterize numerous fundamental properties of the galaxies as well as dark matter halos and subhalos with unprecedented robustness and accuracy. Here we demonstrate the usefulness and accuracy of strong lensing as a probe for characterising the properties of cluster members as well as dark matter halos, to show that such characterisation carried out via lensing analyses alone is as viable as those carried out through a combination of spectroscopy and lensing analyses.Our study uses focuses on the early-type galaxy cluster MACS J1149.5+2223 at redshift 0.54 in the Hubble Frontier Fields (HFF) program, where the first magnified and spatially resolved multiple images of supernova (SN) “Refsdal” and its late-type host galaxy at redshift 1.489 were detected. The Refsdal system is unique in being the first ever multiply-imaged supernova, with it’s first four images appearing in an Einstein Cross configuration around one of the cluster members in 2015. In our lensing analyses we use HST data of the multiply-imaged SN Refsdal to constrain the dynamical masses, velocity dispersions, and virial radii of individual galaxies and dark matter halos in the MACS J1149.5+2223 cluster. For our lensing models we select a sample of 300 cluster members within approximately 500 kpc from the BCG, and a set of reliable multiple images associated with 18 distinct knots in the SN host spiral galaxy, as well as multiple images of the supernova itself. Our results provide accurate measurements of the masses, velocity dispersions, and radii of the cluster’s dark matter halo as well as three chosen members galaxies, in strong agreement with those obtained by Grillo et al 2015, demonstrating the usefulness of strong

  17. What if LIGO's gravitational wave detections are strongly lensed by massive galaxy clusters?

    Science.gov (United States)

    Smith, Graham P.; Jauzac, Mathilde; Veitch, John; Farr, Will M.; Massey, Richard; Richard, Johan

    2018-04-01

    Motivated by the preponderance of so-called `heavy black holes' in the binary black hole (BBH) gravitational wave (GW) detections to date, and the role that gravitational lensing continues to play in discovering new galaxy populations, we explore the possibility that the GWs are strongly lensed by massive galaxy clusters. For example, if one of the GW sources were actually located at z = 1, then the rest-frame mass of the associated BHs would be reduced by a factor of ˜2. Based on the known populations of BBH GW sources and strong-lensing clusters, we estimate a conservative lower limit on the number of BBH mergers detected per detector year at LIGO/Virgo's current sensitivity that are multiply-imaged, of Rdetect ≃ 10-5 yr-1. This is equivalent to rejecting the hypothesis that one of the BBH GWs detected to date was multiply-imaged at ≲4σ. It is therefore unlikely, but not impossible, that one of the GWs is multiply-imaged. We identify three spectroscopically confirmed strong-lensing clusters with well-constrained mass models within the 90 per cent credible sky localizations of the BBH GWs from LIGO's first observing run. In the event that one of these clusters multiply-imaged one of the BBH GWs, we predict that 20-60 per cent of the putative next appearances of the GWs would be detectable by LIGO, and that they would arrive at Earth within 3yr of first detection.

  18. Generalised model-independent characterisation of strong gravitational lenses. I. Theoretical foundations

    Science.gov (United States)

    Wagner, J.

    2017-05-01

    We extend our model-independent approach for characterising strong gravitational lenses to its most general form to leading order and use the orientation angles of a set of multiple images with respect to their connection line(s) in addition to the relative distances between the images, their ellipticities, and time-delays. For two symmetric images that straddle the critical curve, the orientation angle additionally allows us to determine the slope of the critical curve and a second (reduced) flexion coefficient at the critical point on the connection line between the images. It also allows us to drop the symmetry assumption that the axis of largest image extension is orthogonal to the critical curve. For three images almost forming a giant arc, the degree of assumed image symmetry is also reduced to the most general case, describing image configurations for which the source need not be placed on the symmetry axis of the two folds that unite at the cusp. For a given set of multiple images, we set limits on the applicability of our approach, show which information can be obtained in cases of merging images, and analyse the accuracy achievable due to the Taylor expansion of the lensing potential for the fold case on a galaxy cluster scale Navarro-Frenk-White-profile, a fold and cusp case on a galaxy cluster scale singular isothermal ellipse, and compare the generalised approach with our previously published one. The position of the critical points is reconstructed with less than 5'' deviation for multiple images closer to the critical points than 30% of the (effective) Einstein radius. The slope of the critical curve at a fold and its shape in the vicinity of a cusp deviate less than 20% from the true values for distances of the images to the critical points less than 15% of the (effective) Einstein radius.

  19. The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses

    Science.gov (United States)

    Shu, Yiping; Brownstein, Joel R.; Bolton, Adam S.; Koopmans, Léon V. E.; Treu, Tommaso; Montero-Dorta, Antonio D.; Auger, Matthew W.; Czoske, Oliver; Gavazzi, Raphaël; Marshall, Philip J.; Moustakas, Leonidas A.

    2017-12-01

    We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06–0.44, and background sources are emission-line galaxies at redshifts 0.22–1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3 × 1010 M ⊙ to 2 × 1011 M ⊙. In Shu et al., we have derived the total stellar mass of the S4TM lenses to be 5 × 1010 M ⊙ to 1 × 1012 M ⊙. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with HST program #12210.

  20. Testing the Speed of Gravitational Waves over Cosmological Distances with Strong Gravitational Lensing.

    Science.gov (United States)

    Collett, Thomas E; Bacon, David

    2017-03-03

    Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al. [J. Cosmol. Astropart. Phys.10 (2014) 080JCAPBP1475-751610.1088/1475-7516/2014/10/080] forecast that 50-100 strongly lensed GW events will be observed each year with the Einstein Telescope. A single strongly lensed GW event would produce robust constraints on c_{GW}/c_{γ} at the 10^{-7} level, if a high-energy EM counterpart is observed within the field of view of an observing γ-ray burst monitor.

  1. OBSERVED SCALING RELATIONS FOR STRONG LENSING CLUSTERS: CONSEQUENCES FOR COSMOLOGY AND CLUSTER ASSEMBLY

    International Nuclear Information System (INIS)

    Comerford, Julia M.; Moustakas, Leonidas A.; Natarajan, Priyamvada

    2010-01-01

    Scaling relations of observed galaxy cluster properties are useful tools for constraining cosmological parameters as well as cluster formation histories. One of the key cosmological parameters, σ 8 , is constrained using observed clusters of galaxies, although current estimates of σ 8 from the scaling relations of dynamically relaxed galaxy clusters are limited by the large scatter in the observed cluster mass-temperature (M-T) relation. With a sample of eight strong lensing clusters at 0.3 8 , but combining the cluster concentration-mass relation with the M-T relation enables the inclusion of unrelaxed clusters as well. Thus, the resultant gains in the accuracy of σ 8 measurements from clusters are twofold: the errors on σ 8 are reduced and the cluster sample size is increased. Therefore, the statistics on σ 8 determination from clusters are greatly improved by the inclusion of unrelaxed clusters. Exploring cluster scaling relations further, we find that the correlation between brightest cluster galaxy (BCG) luminosity and cluster mass offers insight into the assembly histories of clusters. We find preliminary evidence for a steeper BCG luminosity-cluster mass relation for strong lensing clusters than the general cluster population, hinting that strong lensing clusters may have had more active merging histories.

  2. STRONG GRAVITATIONAL LENSING BY THE SUPER-MASSIVE cD GALAXY IN ABELL 3827

    International Nuclear Information System (INIS)

    Carrasco, E. R.; Gomez, P. L.; Lee, H.; Diaz, R.; Bergmann, M.; Turner, J. E. H.; Miller, B. W.; West, M. J.; Verdugo, T.

    2010-01-01

    We have discovered strong gravitational lensing features in the core of the nearby cluster Abell 3827 by analyzing Gemini South GMOS images. The most prominent strong lensing feature is a highly magnified, ring-shaped configuration of four images around the central cD galaxy. GMOS spectroscopic analysis puts this source at z ∼ 0.2. Located ∼20'' away from the central galaxy is a secondary tangential arc feature which has been identified as a background galaxy with z ∼ 0.4. We have modeled the gravitational potential of the cluster core, taking into account the mass from the cluster, the brightest cluster galaxy (BCG), and other galaxies. We derive a total mass of (2.7 ± 0.4) x 10 13 M sun within 37 h -1 kpc. This mass is an order of magnitude larger than that derived from X-ray observations. The total mass derived from lensing data suggests that the BCG in this cluster is perhaps the most massive galaxy in the nearby universe.

  3. Herschel extreme lensing line observations: Dynamics of two strongly lensed star-forming galaxies near redshift z = 2

    International Nuclear Information System (INIS)

    Rhoads, James E.; Malhotra, Sangeeta; Allam, Sahar; Carilli, Chris; Combes, Françoise; Finkelstein, Keely; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; Guillard, Pierre; Nesvadba, Nicole; Rigby, Jane; Spaans, Marco; Strauss, Michael A.

    2014-01-01

    We report on two regularly rotating galaxies at redshift z ≈ 2, using high-resolution spectra of the bright [C II] 158 μm emission line from the HIFI instrument on the Herschel Space Observatory. Both SDSS090122.37+181432.3 ( S 0901 ) and SDSSJ120602.09+514229.5 ( t he Clone ) are strongly lensed and show the double-horned line profile that is typical of rotating gas disks. Using a parametric disk model to fit the emission line profiles, we find that S0901 has a rotation speed of vsin (i) ≈ 120 ± 7 km s –1 and a gas velocity dispersion of σ g < 23 km s –1 (1σ). The best-fitting model for the Clone is a rotationally supported disk having vsin (i) ≈ 79 ± 11 km s –1 and σ g ≲ 4 km s –1 (1σ). However, the Clone is also consistent with a family of dispersion-dominated models having σ g = 92 ± 20 km s –1 . Our results showcase the potential of the [C II] line as a kinematic probe of high-redshift galaxy dynamics: [C II] is bright, accessible to heterodyne receivers with exquisite velocity resolution, and traces dense star-forming interstellar gas. Future [C II] line observations with ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.

  4. Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

    Science.gov (United States)

    Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.; Collett, Thomas E.

    2018-03-01

    Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ∼2 over previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Accounting for microlensing, the 1–2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.

  5. Reducing biases on H0 measurements using strong lensing and galaxy dynamics: results from the EAGLE simulation

    Science.gov (United States)

    Tagore, Amitpal S.; Barnes, David J.; Jackson, Neal; Kay, Scott T.; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2018-03-01

    Cosmological parameter constraints from observations of time-delay lenses are becoming increasingly precise. However, there may be significant bias and scatter in these measurements due to, among other things, the so-called mass-sheet degeneracy. To estimate these uncertainties, we analyse strong lenses from the largest EAGLE hydrodynamical simulation. We apply a mass-sheet transformation to the radial density profiles of lenses, and by selecting lenses near isothermality, we find that the bias on H0 can be reduced to 5 per cent with an intrinsic scatter of 10 per cent, confirming previous results performed on a different simulation data set. We further investigate whether combining lensing observables with kinematic constraints helps to minimize this bias. We do not detect any significant dependence of the bias on lens model parameters or observational properties of the galaxy, but depending on the source-lens configuration, a bias may still exist. Cross lenses provide an accurate estimate of the Hubble constant, while fold (double) lenses tend to be biased low (high). With kinematic constraints, double lenses show bias and intrinsic scatter of 6 per cent and 10 per cent, respectively, while quad lenses show bias and intrinsic scatter of 0.5 per cent and 10 per cent, respectively. For lenses with a reduced χ2 > 1, a power-law dependence of the χ2 on the lens environment (number of nearby galaxies) is seen. Lastly, we model, in greater detail, the cases of two double lenses that are significantly biased. We are able to remove the bias, suggesting that the remaining biases could also be reduced by carefully taking into account additional sources of systematic uncertainty.

  6. DES meets Gaia: discovery of strongly lensed quasars from a multiplet search

    Energy Technology Data Exchange (ETDEWEB)

    Agnello, A.; et al.

    2017-11-10

    We report the discovery, spectroscopic confirmation and first lens models of the first two, strongly lensed quasars from a combined search in WISE and Gaia over the DES footprint. The four-image lensWGD2038-4008 (r.a.=20:38:02.65, dec.=-40:08:14.64) has source- and lens-redshifts $z_{s}=0.777 \\pm 0.001$ and $z_l = 0.230 \\pm 0.002$ respectively. Its deflector has effective radius $R_{\\rm eff} \\approx 3.4^{\\prime\\prime}$, stellar mass $\\log(M_{\\star}/M_{\\odot}) = 11.64^{+0.20}_{-0.43}$, and shows extended isophotal shape variation. Simple lens models yield Einstein radii $R_{\\rm E}=(1.30\\pm0.04)^{\\prime\\prime},$ axis ratio $q=0.75\\pm0.1$ (compatible with that of the starlight) and considerable shear-ellipticity degeneracies. The two-image lensWGD2021-4115 (r.a.=20:21:39.45, dec.=--41:15:57.11) has $z_{s}=1.390\\pm0.001$ and $z_l = 0.335 \\pm 0.002$, and Einstein radius $R_{\\rm E} = (1.1\\pm0.1)^{\\prime\\prime},$ but higher-resolution imaging is needed to accurately separate the deflector and faint quasar image. We also show high-rank candidate doubles selected this way, some of which have been independently identified with different techniques, and discuss a DES+WISE quasar multiplet selection.

  7. Probing the Small-scale Structure in Strongly Lensed Systems via Transdimensional Inference

    Science.gov (United States)

    Daylan, Tansu; Cyr-Racine, Francis-Yan; Diaz Rivero, Ana; Dvorkin, Cora; Finkbeiner, Douglas P.

    2018-02-01

    Strong lensing is a sensitive probe of the small-scale density fluctuations in the Universe. We implement a pipeline to model strongly lensed systems using probabilistic cataloging, which is a transdimensional, hierarchical, and Bayesian framework to sample from a metamodel (union of models with different dimensionality) consistent with observed photon count maps. Probabilistic cataloging allows one to robustly characterize modeling covariances within and across lens models with different numbers of subhalos. Unlike traditional cataloging of subhalos, it does not require model subhalos to improve the goodness of fit above the detection threshold. Instead, it allows the exploitation of all information contained in the photon count maps—for instance, when constraining the subhalo mass function. We further show that, by not including these small subhalos in the lens model, fixed-dimensional inference methods can significantly mismodel the data. Using a simulated Hubble Space Telescope data set, we show that the subhalo mass function can be probed even when many subhalos in the sample catalogs are individually below the detection threshold and would be absent in a traditional catalog. The implemented software, Probabilistic Cataloger (PCAT) is made publicly available at https://github.com/tdaylan/pcat.

  8. Strong-lensing analysis of A2744 with MUSE and Hubble Frontier Fields images

    Science.gov (United States)

    Mahler, G.; Richard, J.; Clément, B.; Lagattuta, D.; Schmidt, K.; Patrício, V.; Soucail, G.; Bacon, R.; Pello, R.; Bouwens, R.; Maseda, M.; Martinez, J.; Carollo, M.; Inami, H.; Leclercq, F.; Wisotzki, L.

    2018-01-01

    We present an analysis of Multi Unit Spectroscopic Explorer (MUSE) observations obtained on the massive Frontier Fields (FFs) cluster A2744. This new data set covers the entire multiply imaged region around the cluster core. The combined catalogue consists of 514 spectroscopic redshifts (with 414 new identifications). We use this redshift information to perform a strong-lensing analysis revising multiple images previously found in the deep FF images, and add three new MUSE-detected multiply imaged systems with no obvious Hubble Space Telescope counterpart. The combined strong-lensing constraints include a total of 60 systems producing 188 images altogether, out of which 29 systems and 83 images are spectroscopically confirmed, making A2744 one of the most well-constrained clusters to date. Thanks to the large amount of spectroscopic redshifts, we model the influence of substructures at larger radii, using a parametrization including two cluster-scale components in the cluster core and several group scale in the outskirts. The resulting model accurately reproduces all the spectroscopic multiple systems, reaching an rms of 0.67 arcsec in the image plane. The large number of MUSE spectroscopic redshifts gives us a robust model, which we estimate reduces the systematic uncertainty on the 2D mass distribution by up to ∼2.5 times the statistical uncertainty in the cluster core. In addition, from a combination of the parametrization and the set of constraints, we estimate the relative systematic uncertainty to be up to 9 per cent at 200 kpc.

  9. The inner mass power spectrum of galaxies using strong gravitational lensing: beyond linear approximation

    Science.gov (United States)

    Chatterjee, Saikat; Koopmans, Léon V. E.

    2018-02-01

    In the last decade, the detection of individual massive dark matter sub-haloes has been possible using potential correction formalism in strong gravitational lens imaging. Here, we propose a statistical formalism to relate strong gravitational lens surface brightness anomalies to the lens potential fluctuations arising from dark matter distribution in the lens galaxy. We consider these fluctuations as a Gaussian random field in addition to the unperturbed smooth lens model. This is very similar to weak lensing formalism and we show that in this way we can measure the power spectrum of these perturbations to the potential. We test the method by applying it to simulated mock lenses of different geometries and by performing an MCMC analysis of the theoretical power spectra. This method can measure density fluctuations in early type galaxies on scales of 1-10 kpc at typical rms levels of a per cent, using a single lens system observed with the Hubble Space Telescope with typical signal-to-noise ratios obtained in a single orbit.

  10. IDCS J1426.5+3508: COSMOLOGICAL IMPLICATIONS OF A MASSIVE, STRONG LENSING CLUSTER AT z = 1.75

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Anthony H.; Fedeli, Cosimo; Mancone, Conor [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Stanford, S. Adam; Zeimann, Greg [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Brodwin, Mark [Department of Physics, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Dey, Arjun [NOAO, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Eisenhardt, Peter R. M.; Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2012-07-10

    The galaxy cluster IDCS J1426.5+3508 at z = 1.75 is the most massive galaxy cluster yet discovered at z > 1.4 and the first cluster at this epoch for which the Sunyaev-Zel'Dovich effect has been observed. In this paper, we report on the discovery with Hubble Space Telescope imaging of a giant arc associated with this cluster. The curvature of the arc suggests that the lensing mass is nearly coincident with the brightest cluster galaxy, and the color is consistent with the arc being a star-forming galaxy. We compare the constraint on M{sub 200} based upon strong lensing with Sunyaev-Zel'Dovich results, finding that the two are consistent if the redshift of the arc is z {approx}> 3. Finally, we explore the cosmological implications of this system, considering the likelihood of the existence of a strongly lensing galaxy cluster at this epoch in a {Lambda}CDM universe. While the existence of the cluster itself can potentially be accommodated if one considers the entire volume covered at this redshift by all current high-redshift cluster surveys, the existence of this strongly lensed galaxy greatly exacerbates the long-standing giant arc problem. For standard {Lambda}CDM structure formation and observed background field galaxy counts this lens system should not exist. Specifically, there should be no giant arcs in the entire sky as bright in F814W as the observed arc for clusters at z {>=} 1.75, and only {approx}0.3 as bright in F160W as the observed arc. If we relax the redshift constraint to consider all clusters at z {>=} 1.5, the expected number of giant arcs rises to {approx}15 in F160W, but the number of giant arcs of this brightness in F814W remains zero. These arc statistic results are independent of the mass of IDCS J1426.5+3508. We consider possible explanations for this discrepancy.

  11. CENTRAL DARK MATTER TRENDS IN EARLY-TYPE GALAXIES FROM STRONG LENSING, DYNAMICS, AND STELLAR POPULATIONS

    International Nuclear Information System (INIS)

    Tortora, C.; Jetzer, P.; Napolitano, N. R.; Romanowsky, A. J.

    2010-01-01

    We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift (z ∼ 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z ∼ 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano et al. and suggest negligible evidence of galaxy evolution over the last ∼2.5 Gyr other than passive stellar aging.

  12. Strong lensing probability in TeVeS (tensor-vector-scalar) theory

    Energy Technology Data Exchange (ETDEWEB)

    Chen Daming, E-mail: cdm@bao.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2008-01-15

    We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor-vector-scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with {Omega}{sub b} = 0.04 and {Omega}{sub {Lambda}} = 0.5 and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter, Heavens and Jimenez 2004 Mon. Not. R. Astron. Soc. 355 764) determined from SDSS data release 1 and Fontana (Fontana et al 2006 Astron. Astrophys. 459 745) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses from singular isothermal sphere galaxy halos in LCDM (Lambda cold dark matter) with a Schechter-fit velocity function, and the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function {mu}(x) = x/(1+x) combined with Fontana GSMF matches the results from CLASS/JVAS quite well.

  13. Strong lensing probability in TeVeS (tensor–vector–scalar) theory

    International Nuclear Information System (INIS)

    Chen Daming

    2008-01-01

    We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor–vector–scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with Ω b = 0.04 and Ω Λ = 0.5 and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter, Heavens and Jimenez 2004 Mon. Not. R. Astron. Soc. 355 764) determined from SDSS data release 1 and Fontana (Fontana et al 2006 Astron. Astrophys. 459 745) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses from singular isothermal sphere galaxy halos in LCDM (Lambda cold dark matter) with a Schechter-fit velocity function, and the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function μ(x) = x/(1+x) combined with Fontana GSMF matches the results from CLASS/JVAS quite well

  14. Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

    Science.gov (United States)

    Perreault Levasseur, Laurence; Hezaveh, Yashar D.; Wechsler, Risa H.

    2017-11-01

    In Hezaveh et al. we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational-lensing systems. Here we demonstrate a method for obtaining the uncertainties of these parameters. We review the framework of variational inference to obtain approximate posteriors of Bayesian neural networks and apply it to a network trained to estimate the parameters of the Singular Isothermal Ellipsoid plus external shear and total flux magnification. We show that the method can capture the uncertainties due to different levels of noise in the input data, as well as training and architecture-related errors made by the network. To evaluate the accuracy of the resulting uncertainties, we calculate the coverage probabilities of marginalized distributions for each lensing parameter. By tuning a single variational parameter, the dropout rate, we obtain coverage probabilities approximately equal to the confidence levels for which they were calculated, resulting in accurate and precise uncertainty estimates. Our results suggest that the application of approximate Bayesian neural networks to astrophysical modeling problems can be a fast alternative to Monte Carlo Markov Chains, allowing orders of magnitude improvement in speed.

  15. Mass density slope of elliptical galaxies from strong lensing and resolved stellar kinematics

    Science.gov (United States)

    Lyskova, N.; Churazov, E.; Naab, T.

    2018-04-01

    We discuss constraints on the mass density distribution (parametrized as ρ ∝ r-γ) in early-type galaxies provided by strong lensing and stellar kinematics data. The constraints come from mass measurements at two `pinch' radii. One `pinch' radius r1 = 2.2REinst is defined such that the Einstein (i.e. aperture) mass can be converted into the spherical mass almost independently of the mass-model. Another `pinch' radius r2 = Ropt is chosen so that the dynamical mass, derived from the line-of-sight velocity dispersion, is least sensitive to the anisotropy of stellar orbits. We verified the performance of this approach on a sample of simulated elliptical galaxies and on a sample of 15 SLACS lens galaxies at 0.01 ≤ z ≤ 0.35, which have already been analysed in Barnabè et al. by the self-consistent joint lensing and kinematic code. For massive simulated galaxies, the density slope γ is recovered with an accuracy of ˜13 per cent, unless r1 and r2 happen to be close to each other. For SLACS galaxies, we found good overall agreement with the results of Barnabè et al. with a sample-averaged slope γ = 2.1 ± 0.05. Although the two-pinch-radii approach has larger statistical uncertainties, it is much simpler and uses only few arithmetic operations with directly observable quantities.

  16. Interpreting the Strongly Lensed Supernova iPTF16geu: Time Delay Predictions, Microlensing, and Lensing Rates

    Energy Technology Data Exchange (ETDEWEB)

    More, Anupreeta; Oguri, Masamune; More, Surhud [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), University of Tokyo, Chiba 277-8583 (Japan); Suyu, Sherry H. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Lee, Chien-Hsiu, E-mail: anupreeta.more@ipmu.jp [Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720 (United States)

    2017-02-01

    We present predictions for time delays between multiple images of the gravitationally lensed supernova, iPTF16geu, which was recently discovered from the intermediate Palomar Transient Factory (iPTF). As the supernova is of Type Ia where the intrinsic luminosity is usually well known, accurately measured time delays of the multiple images could provide tight constraints on the Hubble constant. According to our lens mass models constrained by the Hubble Space Telescope F814W image, we expect the maximum relative time delay to be less than a day, which is consistent with the maximum of 100 hr reported by Goobar et al. but places a stringent upper limit. Furthermore, the fluxes of most of the supernova images depart from expected values suggesting that they are affected by microlensing. The microlensing timescales are small enough that they may pose significant problems to measure the time delays reliably. Our lensing rate calculation indicates that the occurrence of a lensed SN in iPTF is likely. However, the observed total magnification of iPTF16geu is larger than expected, given its redshift. This may be a further indication of ongoing microlensing in this system.

  17. SUB-KILOPARSEC IMAGING OF COOL MOLECULAR GAS IN TWO STRONGLY LENSED DUSTY, STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, J. S.; Marrone, D. P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aravena, M. [Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile); Béthermin, M.; Breuck, C. de [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Ave, Cambridge CB3 0HA (United Kingdom); Carlstrom, J. E. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chapman, S. C.; Rotermund, K. M. [Dalhousie University, Halifax, Nova Scotia (Canada); Collier, J. D.; Galvin, T.; Grieve, K.; O’Brien, A. [University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751 (Australia); Fassnacht, C. D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Gonzalez, A. H.; Ma, J. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); González-López, J. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Hezaveh, Y. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Malkan, M., E-mail: jspilker@as.arizona.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); and others

    2015-10-01

    We present spatially resolved imaging obtained with the Australia Telescope Compact Array (ATCA) of three CO lines in two high-redshift gravitationally lensed dusty star-forming galaxies, discovered by the South Pole Telescope. Strong lensing allows us to probe the structure and dynamics of the molecular gas in these two objects, at z = 2.78 and z = 5.66, with effective source-plane resolution of less than 1 kpc. We model the lensed emission from multiple CO transitions and the dust continuum in a consistent manner, finding that the cold molecular gas as traced by low-J CO always has a larger half-light radius than the 870 μm dust continuum emission. This size difference leads to up to 50% differences in the magnification factor for the cold gas compared to dust. In the z = 2.78 galaxy, these CO observations confirm that the background source is undergoing a major merger, while the velocity field of the other source is more complex. We use the ATCA CO observations and comparable resolution Atacama Large Millimeter/submillimeter Array dust continuum imaging of the same objects to constrain the CO–H{sub 2} conversion factor with three different procedures, finding good agreement between the methods and values consistent with those found for rapidly star-forming systems. We discuss these galaxies in the context of the star formation—gas mass surface density relation, noting that the change in emitting area with observed CO transition must be accounted for when comparing high-redshift galaxies to their lower redshift counterparts.

  18. TESTING GRAVITATIONAL LENSING AS THE SOURCE OF ENHANCED STRONG Mg II ABSORPTION TOWARD GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Rapoport, Sharon; Onken, Christopher A.; Schmidt, Brian P.; Tucker, Brad E. [Research School of Astronomy and Astrophysics, Australian National University, Weston Creek, ACT 2611 (Australia); Wyithe, J. Stuart B. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Levan, Andrew J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2012-08-01

    Sixty percent of gamma-ray bursts (GRBs) reveal strong Mg II absorbing systems, which is a factor of {approx}2 times the rate seen along lines of sight to quasars. Previous studies argue that the discrepancy in the strong Mg II covering factor is most likely to be the result of either quasars being obscured due to dust or the consequence of many GRBs being strongly gravitationally lensed. We analyze observations of quasars that show strong foreground Mg II absorption. We find that GRB lines of sight pass closer to bright galaxies than would be expected for random lines of sight within the impact parameter expected for strong Mg II absorption. While this cannot be explained by obscuration in the GRB sample, it is a natural consequence of gravitational lensing. Upon examining the particular configurations of galaxies near a sample of GRBs with strong Mg II absorption, we find several intriguing lensing candidates. Our results suggest that lensing provides a viable contribution to the observed enhancement of strong Mg II absorption along lines of sight to GRBs, and we outline the future observations required to test this hypothesis conclusively.

  19. SDSS-IV MaNGA: The Spectroscopic Discovery of Strongly Lensed Galaxies

    Science.gov (United States)

    Talbot, Michael S.; Brownstein, Joel R.; Bolton, Adam S.; Bundy, Kevin; Andrews, Brett H.; Cherinka, Brian; Collett, Thomas E.; More, Anupreeta; More, Surhud; Sonnenfeld, Alessandro; Vegetti, Simona; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.

    2018-03-01

    We present a catalogue of 38 spectroscopically detected strong galaxy-galaxy gravitational lens candidates identified in the Sloan Digital Sky Survey IV (SDSS-IV). We were able to simulate narrow-band images for 8 of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with 2 background source-planes. One of these compound systems shows clear lensing features in the narrow-band image. Our sample is based on 2812 galaxies observed by the Mapping Nearby Galaxies at APO (MaNGA) integral field unit (IFU). This Spectroscopic Identification of Lensing Objects (SILO) survey extends the methodology of the Sloan Lens ACS Survey (SLACS) and BOSS Emission-Line Survey (BELLS) to lower redshift and multiple IFU spectra. We searched ˜1.5 million spectra, of which 3065 contained multiple high signal-to-noise background emission-lines or a resolved [O II] doublet, that are included in this catalogue. Upon manual inspection, we discovered regions with multiple spectra containing background emission-lines at the same redshift, providing evidence of a common source-plane geometry which was not possible in previous SLACS and BELLS discovery programs. We estimate more than half of our candidates have an Einstein radius ≳ 1.7", which is significantly greater than seen in SLACS and BELLS. These larger Einstein radii produce more extended images of the background galaxy increasing the probability that a background emission-line will enter one of the IFU spectroscopic fibres, making detection more likely.

  20. Chandra and ALMA observations of the nuclear activity in two strongly lensed star-forming galaxies

    Science.gov (United States)

    Massardi, M.; Enia, A. F. M.; Negrello, M.; Mancuso, C.; Lapi, A.; Vignali, C.; Gilli, R.; Burkutean, S.; Danese, L.; Zotti, G. De

    2018-02-01

    Aim. According to coevolutionary scenarios, nuclear activity and star formation play relevant roles in the early stages of galaxy formation. We aim at identifying them in high-redshift galaxies by exploiting high-resolution and high-sensitivity X-ray and millimeter-wavelength data to confirm the presence or absence of star formation and nuclear activity and describe their relative roles in shaping the spectral energy distributions and in contributing to the energy budgets of the galaxies. Methods: We present the data, model, and analysis in the X-ray and millimeter (mm) bands for two strongly lensed galaxies, SDP.9 (HATLAS J090740.0-004200) and SDP.11 (HATLAS J091043.1-000322), which we selected in the Herschel-ATLAS catalogs for their excess emission in the mid-IR regime at redshift ≳1.5. This emission suggests nuclear activity in the early stages of galaxy formation. We observed both of them with Chandra ACIS-S in the X-ray regime and analyzed the high-resolution mm data that are available in the ALMA Science Archive for SDP.9. By combining the information available in mm, optical, and X-ray bands, we reconstructed the source morphology. Results: Both targets were detected in the X-ray, which strongly indicates highly obscured nuclear activity. ALMA observations for SDP.9 for the continuum and CO(6-5) spectral line with high resolution (0.02 arcsec corresponding to 65 pc at the distance of the galaxy) allowed us to estimate the lensed galaxy redshift to a better accuracy than pre-ALMA estimates (1.5753 ± 0.0003) and to model the emission of the optical, millimetric, and X-ray band for this galaxy. We demonstrate that the X-ray emission is generated in the nuclear environment, which strongly supports that this object has nuclear activity. On the basis of the X-ray data, we attempt an estimate of the black hole properties in these galaxies. Conclusions: By taking advantage of the lensing magnification, we identify weak nuclear activity associated with high

  1. Antireflection Coatings for Strongly Curved Glass Lenses by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Kristin Pfeiffer

    2017-08-01

    Full Text Available Antireflection (AR coatings are indispensable in numerous optical applications and are increasingly demanded on highly curved optical components. In this work, optical thin films of SiO2, Al2O3, TiO2 and Ta2O5 were prepared by atomic layer deposition (ALD, which is based on self-limiting surface reactions leading to a uniform film thickness on arbitrarily shaped surfaces. Al2O3/TiO2/SiO2 and Al2O3/Ta2O5/SiO2 AR coatings were successfully applied in the 400–750 nm and 400–700 nm spectral range, respectively. Less than 0.6% reflectance with an average of 0.3% has been measured on a fused silica hemispherical (half-ball lens with 4 mm diameter along the entire lens surface at 0° angle of incidence. The reflectance on a large B270 aspherical lens with height of 25 mm and diameter of 50 mm decreased to less than 1% with an average reflectance < 0.3%. The results demonstrate that ALD is a promising technology for deposition of uniform optical layers on strongly curved lenses without complex in situ thickness monitoring.

  2. A MAGNIFIED GLANCE INTO THE DARK SECTOR: PROBING COSMOLOGICAL MODELS WITH STRONG LENSING IN A1689

    International Nuclear Information System (INIS)

    Magaña, Juan; Motta, V.; Cárdenas, Victor H.; Verdugo, T.; Jullo, Eric

    2015-01-01

    In this paper we constrain four alternative models to the late cosmic acceleration in the universe: Chevallier–Polarski–Linder (CPL), interacting dark energy (IDE), Ricci holographic dark energy (HDE), and modified polytropic Cardassian (MPC). Strong lensing (SL) images of background galaxies produced by the galaxy cluster Abell 1689 are used to test these models. To perform this analysis we modify the LENSTOOL lens modeling code. The value added by this probe is compared with other complementary probes: Type Ia supernovae (SN Ia), baryon acoustic oscillations (BAO), and cosmic microwave background (CMB). We found that the CPL constraints obtained for the SL data are consistent with those estimated using the other probes. The IDE constraints are consistent with the complementary bounds only if large errors in the SL measurements are considered. The Ricci HDE and MPC constraints are weak, but they are similar to the BAO, SN Ia, and CMB estimations. We also compute the figure of merit as a tool to quantify the goodness of fit of the data. Our results suggest that the SL method provides statistically significant constraints on the CPL parameters but is weak for those of the other models. Finally, we show that the use of the SL measurements in galaxy clusters is a promising and powerful technique to constrain cosmological models. The advantage of this method is that cosmological parameters are estimated by modeling the SL features for each underlying cosmology. These estimations could be further improved by SL constraints coming from other galaxy clusters

  3. Probing the cosmic distance duality with strong gravitational lensing and supernovae Ia data

    Energy Technology Data Exchange (ETDEWEB)

    Holanda, R.F.L. [Departamento de Física, Universidade Estadual da Paraíba, 58429-500, Campina Grande PB (Brazil); Busti, V.C. [Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05508-090, São Paulo SP (Brazil); Alcaniz, J.S., E-mail: holanda@uepb.edu.br, E-mail: vcbusti@astro.iag.usp.br, E-mail: alcaniz@on.br [Departamento de Astronomia, Observatório Nacional, 20921-400, Rio de Janeiro RJ (Brazil)

    2016-02-01

    We propose and perform a new test of the cosmic distance-duality relation (CDDR), D{sub L}(z) / D{sub A}(z) (1 + z){sup 2} = 1, where D{sub A} is the angular diameter distance and D{sub L} is the luminosity distance to a given source at redshift z, using strong gravitational lensing (SGL) and type Ia Supernovae (SNe Ia) data. We show that the ratio D=D{sub A{sub 1{sub 2}}}/D{sub A{sub 2}} and D{sup *}=D{sub L{sub 1{sub 2}}}/D{sub L{sub 2}}, where the subscripts 1 and 2 correspond, respectively, to redshifts z{sub 1} and z{sub 2}, are linked by D/D{sup *}=(1+z{sub 1}){sup 2} if the CDDR is valid. We allow departures from the CDDR by defining two functions for η(z{sub 1}), which equals unity when the CDDR is valid. We find that combination of SGL and SNe Ia data favours no violation of the CDDR at 1σ confidence level (η(z) ≅ 1), in complete agreement with other tests and reinforcing the theoretical pillars of the CDDR.

  4. The Herschel-ATLAS: magnifications and physical sizes of 500-μm-selected strongly lensed galaxies

    Science.gov (United States)

    Enia, A.; Negrello, M.; Gurwell, M.; Dye, S.; Rodighiero, G.; Massardi, M.; De Zotti, G.; Franceschini, A.; Cooray, A.; van der Werf, P.; Birkinshaw, M.; Michałowski, M. J.; Oteo, I.

    2018-04-01

    We perform lens modelling and source reconstruction of Sub-millimetre Array (SMA) data for a sample of 12 strongly lensed galaxies selected at 500μm in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). A previous analysis of the same data set used a single Sérsic profile to model the light distribution of each background galaxy. Here we model the source brightness distribution with an adaptive pixel scale scheme, extended to work in the Fourier visibility space of interferometry. We also present new SMA observations for seven other candidate lensed galaxies from the H-ATLAS sample. Our derived lens model parameters are in general consistent with previous findings. However, our estimated magnification factors, ranging from 3 to 10, are lower. The discrepancies are observed in particular where the reconstructed source hints at the presence of multiple knots of emission. We define an effective radius of the reconstructed sources based on the area in the source plane where emission is detected above 5σ. We also fit the reconstructed source surface brightness with an elliptical Gaussian model. We derive a median value reff ˜ 1.77 kpc and a median Gaussian full width at half-maximum ˜1.47 kpc. After correction for magnification, our sources have intrinsic star formation rates (SFR) ˜ 900-3500 M⊙ yr-1, resulting in a median SFR surface density ΣSFR ˜ 132 M⊙ yr-1 kpc-2 (or ˜218 M⊙ yr-1 kpc-2 for the Gaussian fit). This is consistent with that observed for other star-forming galaxies at similar redshifts, and is significantly below the Eddington limit for a radiation pressure regulated starburst.

  5. VizieR Online Data Catalog: Spectroscopy of strong lensing galaxy clusters (Carrasco+, 2017)

    Science.gov (United States)

    Carrasco, M.; Barrientos, L. F.; Anguita, T.; Garcia-Vergara, C.; Bayliss, M.; Gladders, M.; Gilbank, D.; Yee, H. K. C.; West, M.

    2017-07-01

    The cluster sample presented here is a subset of a larger sample of more than one hundred strong lensing (SL)-selected clusters that have been identified primarily in Second Red-Sequence Cluster Survey (RCS-2; Gilbank+ 2011AJ....141...94G) imaging data. The median seeing of the RCS-2 survey is ~0.7". We supplement the RCS-2 SL-selected cluster sample with a few systems chosen to fill R.A. gaps that were similarly selected from the Sloan Digital Sky Survey (SDSS, see II/294). We performed a comprehensive spectroscopic follow-up of 29 SL-selected galaxy clusters primarily from the Red-Sequence Cluster Survey Giant Arc (RCSGA; Bayliss 2012ApJ...744..156B; M. D. Gladders et al. 2016, in preparation); 7 of these clusters were previously unpublished. The cluster sample is presented in Table 1. Most of the imaging data presented here have been obtained from the RCS-2 survey. They were collected in queue-scheduled mode with MegaCam at the 3.6m Canada-France-Hawaii Telescope (CFHT), between the semesters 2003A and 2007B inclusive. We have also obtained pre-imaging of our clusters in B, R, and I bands, with the Focal Reducer and low dispersion Spectrograph 2 (FORS2) at the ESO 8.2m Very Large Telescope (VLT), in queue mode. The FORS2/VLT observations were carried out between 2006 October and 2010 March using the Multi-object spectroscopy. We have also performed spectroscopic observations with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on the 6.5m Magellan (Baade) telescope at LCO. The IMACS/Magellan observations were collected during six different runs between 2008 June and 2011 March. (4 data files).

  6. Kinematics, Turbulence and Star Formation of z ˜1 Strongly Lensed Galaxies seen with MUSE

    Science.gov (United States)

    Patrício, V.; Richard, J.; Carton, D.; Contini, T.; Epinat, B.; Brinchmann, J.; Schmidt, K. B.; Krajnović, D.; Bouché, N.; Weilbacher, P. M.; Pelló, R.; Caruana, J.; Maseda, M.; Finley, H.; Bauer, F. E.; Martinez, J.; Mahler, G.; Lagattuta, D.; Clément, B.; Soucail, G.; Wisotzki, L.

    2018-03-01

    We analyse a sample of 8 highly magnified galaxies at redshift 0.6 star formation rates, extinction and metallicity from multiple nebular lines, concluding that our sample is representative of z ˜1 star-forming galaxies. We derive the 2D kinematics of these galaxies from the [O II ] emission and model it with a new method that accounts for lensing effects and fits multiple images simultaneously. We use these models to calculate the 2D beam-smearing correction and derive intrinsic velocity dispersion maps. We find them to be fairly homogeneous, with relatively constant velocity dispersions between 15 - 80 km s-1and Gini coefficent of ⪉ 0.3. We do not find any evidence for higher (or lower) velocity dispersions at the positions of bright star-forming clumps. We derive resolved maps of dust attenuation and attenuation-corrected star formation rates from emission lines for two objects in the sample. We use this information to study the relation between resolved star formation rate and velocity dispersion. We find that these quantities are not correlated, and the high velocity dispersions found for relatively low star-forming densities seems to indicate that, at sub-kiloparsec scales, turbulence in high-z discs is mainly dominated by gravitational instability rather than stellar feedback.

  7. A SPECTROSCOPIC SURVEY OF THE FIELDS OF 28 STRONG GRAVITATIONAL LENSES: THE GROUP CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Michelle L.; Zabludoff, Ann I. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Ammons, S. Mark [Lawrence Livermore National Laboratory, Physics Division L-210, 7000 East Avenue, Livermore, CA 94550 (United States); Momcheva, Ivelina G. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Williams, Kurtis A. [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce, TX, 75428 (United States); Keeton, Charles R. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)

    2016-12-20

    With a large, unique spectroscopic survey in the fields of 28 galaxy-scale strong gravitational lenses, we identify groups of galaxies in the 26 adequately sampled fields. Using a group-finding algorithm, we find 210 groups with at least 5 member galaxies; the median number of members is 8. Our sample spans redshifts of 0.04 ≤  z {sub grp} ≤ 0.76 with a median of 0.31, including 174 groups with 0.1 <  z {sub grp} < 0.6. The groups have radial velocity dispersions of 60 ≤  σ {sub grp} ≤ 1200 km s{sup −1} with a median of 350 km s{sup −1}. We also discover a supergroup in field B0712+472 at z = 0.29 that consists of three main groups. We recover groups similar to ∼85% of those previously reported in these fields within our redshift range of sensitivity and find 187 new groups with at least five members. The properties of our group catalog, specifically, (1) the distribution of σ {sub grp}, (2) the fraction of all sample galaxies that are group members, and (3) the fraction of groups with significant substructure, are consistent with those for other catalogs. The distribution of group virial masses agrees well with theoretical expectations. Of the lens galaxies, 12 of 26 (46%) (B1422+231, B1600+434, B2114+022, FBQS J0951+2635, HE0435-1223, HST J14113+5211, MG0751+2716, MGJ1654+1346, PG 1115+080, Q ER 0047-2808, RXJ1131-1231, and WFI J2033-4723) are members of groups with at least five galaxies, and one more (B0712+472) belongs to an additional, visually identified group candidate. There are groups not associated with the lens that still are likely to affect the lens model; in six of 25 (24%) fields (excluding the supergroup), there is at least one massive ( σ {sub grp} ≥ 500 km s{sup −1}) group or group candidate projected within 2′ of the lens.

  8. Discovery of three strongly lensed quasars in the Sloan Digital Sky Survey

    Science.gov (United States)

    Williams, P. R.; Agnello, A.; Treu, T.; Abramson, L. E.; Anguita, T.; Apostolovski, Y.; Chen, G. C.-F.; Fassnacht, C. D.; Hsueh, J.-W.; Lemaux, B. C.; Motta, V.; Oldham, L.; Rojas, K.; Rusu, C. E.; Shajib, A. J.; Wang, X.

    2018-03-01

    We present the discovery of 3 quasar lenses in the Sloan Digital Sky Survey, selected using two novel photometry-based selection techniques. The J0941+0518 system, with two point sources separated by 5.46″ on either side of a galaxy, has source and lens redshifts 1.54 and 0.343. Images of J2257+2349 show two point sources separated by 1.67″ on either side of an E/S0 galaxy. The extracted spectra show two images of the same quasar at zs = 2.10. SDSS J1640+1045 has two quasar spectra at zs = 1.70 and fits to the SDSS and Pan-STARRS images confirm the presence of a galaxy between the two point sources. We observed 56 photometrically selected lens candidates in this follow-up campaign, confirming 3 new lenses, re-discovering one known lens, and ruling out 36 candidates, with 16 still inconclusive. This initial campaign demonstrates the power of purely photometric selection techniques in finding lensed quasars.

  9. The Perspective Effect of Wide-Angle Lenses in Laparoscopes

    NARCIS (Netherlands)

    Wentink, M.; Fischer, H.; Dankelman, J.; Stassen, L.P.S.; Wieringa, P.A.

    2002-01-01

    Purpose: To evaluate the effect of perspective distortion of wide-angle lenses in laparoscopes on hand-eye coordination during endoscopic manipulation. Methods: Sixteen subjects repeatedly performed a standardized positioning task in a pelvi-trainer under two conditions. The subjects had no prior

  10. A strong-lensing elliptical galaxy in the MaNGA survey

    Science.gov (United States)

    Smith, Russell J.

    2017-01-01

    I report discovery of a new galaxy-scale gravitational lens system, identified using public data from the Mapping Galaxies at Apache Point Observatory (MaNGA) survey, as part of a systematic search for lensed background line emitters. The lens is SDSS J170124.01+372258.0, a giant elliptical galaxy with velocity dispersion σ = 256 km s-1, at a redshift of zl = 0.122. After modelling and subtracting the target galaxy light, the integral-field data cube reveals [O II], [O III] and Hβ emission lines corresponding to a source at zs = 0.791, forming an identifiable ring around the galaxy centre. If the ring is formed by a single lensed source, then the Einstein radius is REin ≈ 2.3 arcsec, projecting to ˜5 kpc at the distance of the lens. The total projected lensing mass is MEin = (3.6 ± 0.6) × 1011 M⊙, and the total J-band mass-to-light ratio is 3.0 ± 0.7 solar units. Plausible estimates of the likely dark matter content could reconcile this with a Milky Way-like initial mass function (IMF), for which M/L ≈ 1.5 is expected, but heavier IMFs are by no means excluded with the present data. An alternative interpretation of the system, with a more complex source plane, is also discussed. The discovery of this system bodes well for future lens searches based on MaNGA and other integral-field spectroscopic surveys.

  11. A HIGHLY ELONGATED PROMINENT LENS AT z = 0.87: FIRST STRONG-LENSING ANALYSIS OF EL GORDO

    Energy Technology Data Exchange (ETDEWEB)

    Zitrin, Adi [Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Menanteau, Felipe; Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Coe, Dan [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Barrientos, L. Felipe; Infante, Leopoldo [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica, Casilla 306, Santiago 22 (Chile); Mandelbaum, Rachel, E-mail: adizitrin@gmail.com [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

    2013-06-10

    We present the first strong-lensing (SL) analysis of the galaxy cluster ACT-CL J0102-4915 (El Gordo), in recent HST/ACS images, revealing a prominent strong lens at a redshift of z = 0.87. This finding adds to the already-established unique properties of El Gordo: it is the most massive, hot, X-ray luminous, and bright Sunyaev-Zeldovich effect cluster at z {approx}> 0.6, and the only {sup b}ullet{sup -}like merging cluster known at these redshifts. The lens consists of two merging massive clumps, where, for a source redshift of z{sub s} {approx} 2, each clump exhibits only a small, separate critical area, with a total area of 0.69 {+-} 0.11{open_square}' over the two clumps. For a higher source redshift, z{sub s} {approx} 4, the critical curves of the two clumps merge together into one bigger and very elongated lens (axis ratio {approx_equal} 5.5), enclosing an effective area of 1.44 {+-} 0.22{open_square}'. The critical curves continue expanding with increasing redshift so that for high-redshift sources (z{sub s} {approx}> 9) they enclose an area of {approx}1.91 {+-} 0.30{open_square}' (effective {theta}{sub e} {approx_equal} 46.''8 {+-} 3.''7) and a mass of 6.09 {+-} 1.04 Multiplication-Sign 10{sup 14} M{sub Sun }. According to our model, the area of high magnification ({mu} > 10) for such high-redshift sources is {approx_equal}1.2{open_square}', and the area with {mu} > 5 is {approx_equal}2.3{open_square}', making El Gordo a compelling target for studying the high-redshift universe. We obtain a strong lower limit on the total mass of El Gordo, {approx}> 1.7 Multiplication-Sign 10{sup 15} M{sub Sun} from the SL regime alone, suggesting a total mass of roughly M{sub 200} {approx} 2.3 Multiplication-Sign 10{sup 15} M{sub Sun }. Our results should be revisited when additional spectroscopic and HST imaging data are available.

  12. A STRONGLY LENSED MASSIVE ULTRACOMPACT QUIESCENT GALAXY AT z {approx} 2.4 IN THE COSMOS/UltraVISTA FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Muzzin, Adam; Labbe, Ivo; Franx, Marijn; Holt, J.; Szomoru, Daniel; Van de Sande, Jesse [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Van Dokkum, Pieter [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Brammer, Gabriel [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Marchesini, Danilo [Department of Physics and Astronomy, Tufts University, Medford, MA 06520 (United States); Stefanon, Mauro [Obseratori Astronomic de la Universitat de Valencia, E-46980 Paterna, Valencia (Spain); Buitrago, F.; Dunlop, James [SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJL (United Kingdom); Caputi, K. I. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Fynbo, J. P. U.; Milvang-Jensen, Bo [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Le Fevre, Olivier [Laboratoire d' Astrophysique de Marseille, CNRS and Aix-Marseille Universite, 38 rue Frederic Joliot-Curie, F-13388 Marseille Cedex 13 (France); McCracken, Henry J. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France)

    2012-12-20

    We report the discovery of a massive ultracompact quiescent galaxy that has been strongly lensed into multiple images by a foreground galaxy at z 0.960. This system was serendipitously discovered as a set of extremely K{sub s} -bright high-redshift galaxies with red J - K{sub s} colors using new data from the UltraVISTA YJHK{sub s} near-infrared survey. The system was also previously identified as an optically faint lens/source system using the COSMOS Advanced Camera for Surveys (ACS) imaging by Faure et al. Photometric redshifts for the three brightest images of the source galaxy determined from 27-band photometry place the source at z = 2.4 {+-} 0.1. We provide an updated lens model for the system that is a good fit to the positions and morphologies of the galaxies in the ACS image. The lens model implies that the magnification of the three brightest images is a factor of 4-5. We use the lens model, combined with the K{sub s} -band image, to constrain the size and Sersic profile of the galaxy. The best-fit model is an ultracompact galaxy (R{sub e} = 0.64{sup +0.08}{sub -0.18} kpc, lensing-corrected), with a Sersic profile that is intermediate between a disk and a bulge profile (n 2.2{sup +2.3}{sub -{sub 0.9}}), albeit with considerable uncertainties on the Sersic profile. We present aperture photometry for the source galaxy images that have been corrected for flux contamination from the central lens. The best-fit stellar population model is a massive galaxy (log(M{sub star}/M{sub Sun }) = 10.8{sup +0.1}{sub -0.1}, lensing-corrected) with an age of 1.0{sup +1.0}{sub -0.4} Gyr, moderate dust extinction (A{sub v} = 0.8{sup +0.5}{sub -0.6}), and a low specific star formation rate (log(SSFR) <-11.0 yr{sup -1}). This is typical of massive ''red-and-dead'' galaxies at this redshift and confirms that this source is the first bona fide strongly lensed massive ultracompact quiescent galaxy to be discovered. We conclude with a discussion of the prospects

  13. The Strong Gravitationally Lensed Herschel Galaxy HLock01: Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas

    Science.gov (United States)

    Marques-Chaves, Rui; Pérez-Fournon, Ismael; Gavazzi, Raphael; Martínez-Navajas, Paloma I.; Riechers, Dominik; Rigopoulou, Dimitra; Cabrera-Lavers, Antonio; Clements, David L.; Cooray, Asantha; Farrah, Duncan; Ivison, Rob J.; Jiménez-Ángel, Camilo E.; Nayyeri, Hooshang; Oliver, Seb; Omont, Alain; Scott, Douglas; Shu, Yiping; Wardlow, Julie

    2018-02-01

    The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m UV ≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M * ≃ 5 × 1011 M ⊙), with a highly extinguished stellar component (A V ≃ 4.3 ), the LBG is a young, lower-mass (M * ≃ 1 × 1010 M ⊙), but still luminous (10× {L}UV}* ) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C II λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.

  14. VizieR Online Data Catalog: Strong lensing mass modeling of 4 HFF clusters (Kawamata+, 2016)

    Science.gov (United States)

    Kawamata, R.; Oguri, M.; Ishigaki, M.; Shimasaku, K.; Ouchi, M.

    2018-02-01

    We use the public HFF data (http://www.stsci.edu/hst/campaigns/frontier-fields/) for our analysis. The HFF targets six massive clusters, Abell 2744 (z=0.308), MACS J0416.1-2403 (z=0.397), MACS J0717.5+3745 (z=0.545), MACS J1149.6+2223 (z=0.541), Abell S1063 (z=0.348), and Abell 370 (z=0.375), which have been chosen according to their lensing strength and also their accessibility from major ground-based telescopes. The cluster core and parallel field region of each cluster are observed deeply with the IR channel of Wide Field Camera 3 (WFC3/IR) and the Advanced Camera for Surveys (ACS). As of 2015 October, HST observations for the first four clusters, Abell 2744, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.6+2223, are completed. In this study, we use the Version 1.0 data products of drizzled images with a pixel scale of 0.03"/pixel provided by the Space Telescope Science Institute (STScI). The images for each cluster consist of F435W (B435), F606W (V606), and F814W (i814) images from ACS, and F105W (Y105), F125W (J125), F140W (JH140), and F160W (H160) images from WFC3/IR. (7 data files).

  15. A dusty star-forming galaxy at z = 6 revealed by strong gravitational lensing

    Science.gov (United States)

    Zavala, Jorge A.; Montaña, Alfredo; Hughes, David H.; Yun, Min S.; Ivison, R. J.; Valiante, Elisabetta; Wilner, David; Spilker, Justin; Aretxaga, Itziar; Eales, Stephen; Avila-Reese, Vladimir; Chávez, Miguel; Cooray, Asantha; Dannerbauer, Helmut; Dunlop, James S.; Dunne, Loretta; Gómez-Ruiz, Arturo I.; Michałowski, Michał J.; Narayanan, Gopal; Nayyeri, Hooshang; Oteo, Ivan; Rosa González, Daniel; Sánchez-Argüelles, David; Schloerb, F. Peter; Serjeant, Stephen; Smith, Matthew W. L.; Terlevich, Elena; Vega, Olga; Villalba, Alan; van der Werf, Paul; Wilson, Grant W.; Zeballos, Milagros

    2018-01-01

    Since their discovery, submillimetre-selected galaxies1,2 have revolutionized the field of galaxy formation and evolution. From the hundreds of square degrees mapped at submillimetre wavelengths3-5, only a handful of sources have been confirmed to lie at z > 5 (refs 6-10) and only two at z ≥ 6 (refs 11,12). All of these submillimetre galaxies are rare examples of extreme starburst galaxies with star formation rates of ≳1,000 M⊙ yr-1 and therefore are not representative of the general population of dusty star-forming galaxies. Consequently, our understanding of the nature of these sources, at the earliest epochs, is still incomplete. Here, we report the spectroscopic identification of a gravitationally amplified (μ = 9.3 ± 1.0) dusty star-forming galaxy at z = 6.027. After correcting for gravitational lensing, we derive an intrinsic less-extreme star formation rate of 380 ± 50 M⊙ yr-1 for this source and find that its gas and dust properties are similar to those measured for local ultra luminous infrared galaxies, extending the local trends to a poorly explored territory in the early Universe. The star-formation efficiency of this galaxy is similar to those measured in its local analogues13, despite a 12 Gyr difference in cosmic time.

  16. Modelling high resolution ALMA observations of strongly lensed highly star forming galaxies detected by Herscheltype="fn" rid="fn1" />

    Science.gov (United States)

    Dye, S.; Furlanetto, C.; Dunne, L.; Eales, S. A.; Negrello, M.; Nayyeri, H.; van der Werf, P. P.; Serjeant, S.; Farrah, D.; Michałowski, M. J.; Baes, M.; Marchetti, L.; Cooray, A.; Riechers, D. A.; Amvrosiadis, A.

    2018-02-01

    We have modelled ˜0.1 arcsec resolution ALMA imaging of six strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Our modelling recovers mass properties of the lensing galaxies and, by determining magnification factors, intrinsic properties of the lensed sub-millimetre sources. We find that the lensed galaxies all have high ratios of star formation rate to dust mass, consistent with or higher than the mean ratio for high redshift sub-millimetre galaxies and low redshift ultra-luminous infra-red galaxies. Source reconstruction reveals that most galaxies exhibit disturbed morphologies. Both the cleaned image plane data and the directly observed interferometric visibilities have been modelled, enabling comparison of both approaches. In the majority of cases, the recovered lens models are consistent between methods, all six having mass density profiles that are close to isothermal. However, one system with poor signal to noise shows mildly significant differences.

  17. Constraints on a possible evolution of mass density power-law index in strong gravitational lensing from cosmological data

    Science.gov (United States)

    Holanda, R. F. L.; Pereira, S. H.; Jain, Deepak

    2017-11-01

    In this work, by using strong gravitational lensing (SGL) observations along with Type Ia Supernovae (Union2.1) and gamma-ray burst data (GRBs), we propose a new method to study a possible redshift evolution of γ(z), the mass density power-law index of strong gravitational lensing systems. In this analysis, we assume the validity of cosmic distance duality relation and the flat universe. In order to explore the γ(z) behaviour, three different parametrizations are considered, namely: (P1) γ(zl) = γ0 + γ1zl; (P2) γ(zl) = γ0 + γ1zl/(1 + zl); and (P3) γ(zl) = γ0 + γ1ln (1 + zl), where zl corresponds to lens redshift. If γ0 = 2 and γ1 = 0, the singular isothermal sphere model is recovered. Our method is performed on SGL sub-samples defined by different lens redshifts and velocity dispersions. For the former case, the results are in full agreement with each other, while a 1σ tension between the sub-samples with low (≤250 km s-1) and high (>250 km s-1) velocity dispersions was obtained on the (γ0-γ1) plane. By considering the complete SGL sample, we obtain γ0 ≈ 2 and γ1 ≈ 0 within 1σ c.l. for all γ(z) parametrizations. However, we find the following best-fitting values of γ1: -0.085; -0.16; and -0.12 for P1, P2 and P3 parametrizations, respectively, suggesting a mild evolution for γ(z). By repeating the analysis with Type Ia Supernovae from Joint Light Analysis compilation, GRBs and SGL systems this mild evolution is reinforced.

  18. SEARCHING FOR COOLING SIGNATURES IN STRONG LENSING GALAXY CLUSTERS: EVIDENCE AGAINST BARYONS SHAPING THE MATTER DISTRIBUTION IN CLUSTER CORES

    International Nuclear Information System (INIS)

    Blanchard, Peter K.; Bayliss, Matthew B.; McDonald, Michael; Dahle, Håkon; Gladders, Michael D.; Sharon, Keren; Mushotzky, Richard

    2013-01-01

    The process by which the mass density profile of certain galaxy clusters becomes centrally concentrated enough to produce high strong lensing (SL) cross-sections is not well understood. It has been suggested that the baryonic condensation of the intracluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. In this work, we search for evidence of ongoing ICM cooling in the first large, well-defined sample of SL selected galaxy clusters in the range 0.1 0.2 and shows no statistically significant deviation from the total cluster population. Specific star formation rates, as traced by the strength of the 4000 Å break, D 4000 , are also consistent with the general cluster population. Finally, we use optical imaging of the SL clusters to measure the angular separation, R arc , between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [O II] emission and D 4000 as a function of R arc , a proxy observable for SL cross-sections. D 4000 is constant with all values of R arc , and the [O II] emission fractions show no dependence on R arc for R arc > 10'' and only very marginal evidence of increased weak [O II] emission for systems with R arc < 10''. These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in SL cross-sections

  19. Models of the Strongly Lensed Quasar DES J0408-5354

    Energy Technology Data Exchange (ETDEWEB)

    Agnello, A.; et al.

    2017-02-01

    We present gravitational lens models of the multiply imaged quasar DES J0408-5354, recently discovered in the Dark Energy Survey (DES) footprint, with the aim of interpreting its remarkable quad-like configuration. We first model the DES single-epoch $grizY$ images as a superposition of a lens galaxy and four point-like objects, obtaining spectral energy distributions (SEDs) and relative positions for the objects. Three of the point sources (A,B,D) have SEDs compatible with the discovery quasar spectra, while the faintest point-like image (G2/C) shows significant reddening and a `grey' dimming of $\\approx0.8$mag. In order to understand the lens configuration, we fit different models to the relative positions of A,B,D. Models with just a single deflector predict a fourth image at the location of G2/C but considerably brighter and bluer. The addition of a small satellite galaxy ($R_{\\rm E}\\approx0.2$") in the lens plane near the position of G2/C suppresses the flux of the fourth image and can explain both the reddening and grey dimming. All models predict a main deflector with Einstein radius between $1.7"$ and $2.0",$ velocity dispersion $267-280$km/s and enclosed mass $\\approx 6\\times10^{11}M_{\\odot},$ even though higher resolution imaging data are needed to break residual degeneracies in model parameters. The longest time-delay (B-A) is estimated as $\\approx 85$ (resp. $\\approx125$) days by models with (resp. without) a perturber near G2/C. The configuration and predicted time-delays of J0408-5354 make it an excellent target for follow-up aimed at understanding the source quasar host galaxy and substructure in the lens, and measuring cosmological parameters. We also discuss some lessons learnt from J0408-5354 on lensed quasar finding strategies, due to its chromaticity and morphology.

  20. The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses

    NARCIS (Netherlands)

    Shu, Yiping; Brownstein, Joel R.; Bolton, Adam S.; Koopmans, Léon V. E.; Treu, Tommaso; Montero-Dorta, Antonio D.; Auger, Matthew W.; Czoske, Oliver; Gavazzi, Raphaël; Marshall, Philip J.; Moustakas, Leonidas A.

    2017-01-01

    We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations

  1. Null Geodesics and Strong Field Gravitational Lensing of Black Hole with Global Monopole

    International Nuclear Information System (INIS)

    Iftikhar, Sehrish; Sharif, M.

    2015-01-01

    We study two interesting features of a black hole with an ordinary as well as phantom global monopole. Firstly, we investigate null geodesics which imply unstable orbital motion of particles for both cases. Secondly, we evaluate deflection angle in strong field regime. We then find Einstein rings, magnifications, and observables of the relativistic images for supermassive black hole at the center of galaxy NGC4486B. We also examine time delays for different galaxies and present our results numerically. It is found that the deflection angle for ordinary/phantom global monopole is greater/smaller than that of Schwarzschild black hole. In strong field limit, the remaining properties of these black holes are quite different from the Schwarzschild black hole

  2. FAST VARIABILITY AND MILLIMETER/IR FLARES IN GRMHD MODELS OF Sgr A* FROM STRONG-FIELD GRAVITATIONAL LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal; Marrone, Daniel [Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Medeiros, Lia [Department of Physics, Broida Hall, University of California, Santa Barbara, Santa Barbara, CA 93106 (United States); Sadowski, Aleksander [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Narayan, Ramesh, E-mail: chanc@email.arizona.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-10-20

    We explore the variability properties of long, high-cadence general relativistic magnetohydrodynamic (GRMHD) simulations across the electromagnetic spectrum using an efficient, GPU-based radiative transfer algorithm. We focus on both standard and normal evolution (SANE) and magnetically arrested disk (MAD) simulations with parameters that successfully reproduce the time-averaged spectral properties of Sgr A* and the size of its image at 1.3 mm. We find that the SANE models produce short-timescale variability with amplitudes and power spectra that closely resemble those inferred observationally. In contrast, MAD models generate only slow variability at lower flux levels. Neither set of models shows any X-ray flares, which most likely indicates that additional physics, such as particle acceleration mechanisms, need to be incorporated into the GRMHD simulations to account for them. The SANE models show strong, short-lived millimeter/infrared (IR) flares, with short (≲1 hr) time lags between the millimeter and IR wavelengths, that arise from the combination of short-lived magnetic flux tubes and strong-field gravitational lensing near the horizon. Such events provide a natural explanation for the observed IR flares with no X-ray counterparts.

  3. Strong and weak lensing united: II. The cluster mass distribution of the most X-ray luminous cluster RX J1347.5-1145

    Energy Technology Data Exchange (ETDEWEB)

    Bradač, M.; Erben, T.; Schneider, P.; Hildebrandt, H.; Lombardi, M.; Schirmer, M.; Miralles, J. -M.; Clowe, D.; Schindler, S.

    2005-07-01

    We have shown that the cluster-mass reconstruction method which combines strong and weak gravitational lensing data, developed in the first paper in the series, successfully reconstructs the mass distribution of a simulated cluster. In this paper we apply the method to the ground-based high-quality multi-colour data of RX J1347.5-1145 , the most X-ray luminous cluster to date. A new analysis of the cluster core on very deep, multi-colour data analysis of VLT/FORS data reveals many more arc candidates than previously known for this cluster. The combined strong and weak lensing reconstruction confirms that the cluster is indeed very massive. If the redshift and identification of the multiple-image system as well as the redshift estimates of the source galaxies used for weak lensing are correct, we determine the enclosed cluster mass in a cylinder to M(<360 h -1 kpc)= (1.2± 0.3) x 1015 M. In addition the reconstructed mass distribution follows the distribution found with independent methods (X-ray measurements, SZ). With higher resolution (e.g. HST imaging data) more reliable multiple imaging information can be obtained and the reconstruction can be improved to accuracies greater than what is currently possible with weak and strong lensing techniques.

  4. Strong and Weak Lensing United II: the Cluster Mass Distribution of the Most X-ray Luminous Cluster RX J1347.5-1145

    Energy Technology Data Exchange (ETDEWEB)

    Bradac, M.

    2005-04-13

    We have shown that the cluster-mass reconstruction method which combines strong and weak gravitational lensing data, developed in the first paper in the series, successfully reconstructs the mass distribution of a simulated cluster. In this paper we apply the method to the ground-based high-quality multi-colour data of RX J1347.5-1145, the most X-ray luminous cluster to date. A new analysis of the cluster core on very deep, multi-colour data analysis of VLT/FORS data reveals many more arc candidates than previously known for this cluster. The combined strong and weak lensing reconstruction confirms that the cluster is indeed very massive. If the redshift and identification of the multiple-image system as well as the redshift estimates of the source galaxies used for weak lensing are correct, we determine the enclosed cluster mass in a cylinder to M(< 360h{sup -1}kpc) = (1.2 {+-} 0.3) x 10{sup 15}M{circle_dot}. In addition the reconstructed mass distribution follows the distribution found with independent methods (X-ray measurements, SZ). With higher resolution (e.g. HST imaging data) more reliable multiple imaging information can be obtained and the reconstruction can be improved to accuracies greater than what is currently possible with weak and strong lensing techniques.

  5. Effect of adhered bacteria on the binding of Acanthamoeba to hydrogel lenses.

    Science.gov (United States)

    Gorlin, A I; Gabriel, M M; Wilson, L A; Ahearn, D G

    1996-05-01

    To determine the effect of Pseudomonas aeruginosa and Staphylococcus epidermidis on the binding of Acanthamoeba species to hydrogel lenses. Cells of amebae and bacteria were incubated with different types of hydrogel lenses. Densities of amebae that were bound to the lenses after rinsing were determined from direct counts with a cell detachment procedure and from scintillation counts of cells, which were radiolabeled with tritiated leucine. With both methods, amebae showed significantly increased binding to hydrogel lenses with attached P aeruginosa. The numbers of amebae that were retained on lenses with attached S epidermidis were not significantly different from those that were retained on lenses without bacteria. The binding of amebae to unworn hydrogel lenses, in contrast to the irreversible adherence of P aeruginosa, was tenuous. The binding of Acanthamoeba species to unworn hydrogel lenses was tenuous and appeared to be related to water content, surface tensions, and ionic charge. The presence of adhered P aeruginosa on the hydrogel lenses facilitated the binding of Acanthamoeba species. The cocontamination of lens systems with bacteria (eg, P aeruginosa) may be a prime factor in the development of amebic keratitis.

  6. Effect of xylose on the synthesis of phosphorylcholine and phosphorylethanolamine in rat lenses.

    Science.gov (United States)

    Jernigan, H M; Ekambaram, M C; Blum, P S; Blanchard, M S

    1993-03-01

    Choline, an essential phospholipid precursor, enters the lens by a facilitated transport system and is phosphorylated to form phosphorylcholine (P-choline). Intact lenses incubated with [3H]choline accumulate both [3H]choline and P-[3H]choline. The rate and extent of this accumulation have been used to study the effects of osmotic or oxidative cataractogenic stress, and also to test the ability of compounds to protect lenses from stress-related damage. The initial effect of oxidative stress on choline metabolism is decreased choline transport, but the mechanism by which osmotic stress affects the accumulation of [3H]choline is not understood. The effects of osmotic and oxidative stress on choline influx and metabolism were compared in rat lenses incubated in TC-199 medium. After osmotic stress by incubation with 30 mM xylose for up to 24 hr, lenses accumulated the same amount of radiolabel as controls during a 30 min pulse with [3H]choline. However, if the lenses were exposed to [3H]choline for 6 hr so that accumulation of radiolabel in the lenses was limited by the rate of P-choline synthesis, xylose treated lenses accumulated less choline than controls. Separation of the lenticular radiolabel into [3H]choline and P-[3H]choline confirmed that xylose decreased synthesis of P-choline, although adequate unphosphorylated [3H]choline was available in the lenses. A decrease in P-[3H]ethanolamine synthesis was also seen in xylose-treated lenses incubated with [3H]ethanolamine. Ethanolamine can enter lenses by a non-saturable process which is not dependent upon a transporter. Although xylose decreased P-choline synthesis in intact lenses, neither xylose nor xylitol inhibited choline kinase in lens homogenates.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Effect of yellow-tinted lenses on visual attributes related to sports activities.

    Science.gov (United States)

    Kohmura, Yoshimitsu; Murakami, Shigeki; Aoki, Kazuhiro

    2013-03-01

    The purpose of this study was to clarify the effect of colored lenses on visual attributes related to sports activities. The subjects were 24 students (11 females, 13 males; average age 21.0 ±1.2 years) attending a sports university. Lenses of 5 colors were used: colorless, light yellow, dark yellow, light gray, and dark gray. For each lens, measurements were performed in a fixed order: contrast sensitivity, dynamic visual acuity, depth perception, hand-eye coordination and visual acuity and low-contrast visual acuity. The conditions for the measurements of visual acuity and low-contrast visual acuity were in the order of Evening, Evening+Glare, Day, and Day+Glare. There were no significant differences among lenses in dynamic visual acuity and depth perception. For hand-eye coordination, time was significantly shorter with colorless than dark gray lenses. Contrast sensitivity was significantly higher with colorless, light yellow, and light gray lenses than with dark yellow and dark gray lenses. The low-contrast visual acuity test in the Day+Glare condition showed no significant difference among the lenses. In the Evening condition, low-contrast visual acuity was significantly higher with colorless and light yellow lenses than with dark gray lenses, and in the Evening+Glare condition, low-contrast visual acuity was significantly higher with colorless lenses than with the other colors except light yellow. Under early evening conditions and during sports activities, light yellow lenses do not appear to have an adverse effect on visual attributes.

  8. Effects of refrigeration on daily microbial bioburden of hydrogel lenses.

    Science.gov (United States)

    Lapple, W J; Snyder, A C; Tuovinen, O H

    1987-03-01

    Microbial bioburden of contact lenses was evaluated in connection with lens care by refrigeration. Subjects wore new hydrogel contact lenses for approximately 8 hours. The microbial bioburden initially and after an overnight refrigeration of the lens was evaluated with the use of viable counts on three different media. No major changes in viable counts were observed resulting from this method of storage. Scanning electron microscopy indicated the presence of foreign material on both new and worn lenses, presumed to be debris from lens manufacture and mucoid deposits from daily wear. Microbial colonization was not apparent and single bacterial cells could not be discerned on the micrographs.

  9. Thermal lensing effects on lateral leakage in GaN-based vertical-cavity surface-emitting laser cavities.

    Science.gov (United States)

    Hashemi, Ehsan; Bengtsson, Jörgen; Gustavsson, Johan; Calciati, Marco; Goano, Michele; Haglund, Åsa

    2017-05-01

    Lateral leakage of light has been identified as a detrimental loss source in many suggested and experimentally realized GaN-based VCSELs. In the present work we include thermal effects to realistically account for the substantial Joule heating in these devices. In contrast to what could be expected from the previous results, the induced thermal lensing does not make antiguided cavities more positively guided, so that they approach the unguided regime with extremely high lateral leakage. Rather, thermal lensing strongly suppresses lateral leakage for both antiguided and guided cavities. This is explained in terms of lowered launch of power from the central part of the cavity and/or lower total internal reflection in the peripheral part; the former effect is active in all cavities whereas the latter only contributes to the very strongly reduced leakage in weakly antiguided cavities. Thermal lensing suppresses lateral leakage both for the fundamental and the first higher order mode, but a strong modal discrimination is still achieved for the antiguided cavities. Thus, strongly antiguided cavities could be used to achieve single-mode devices, but at the cost of slightly higher threshold gain and stronger temperature dependent performance characteristics.

  10. Effect of time and washing on the adhesion of Acanthamoeba to extended wear disposable hydrogel contact lenses.

    Science.gov (United States)

    Ramachandran, L; Janakiraman, D; Sharma, S; Rao, G N

    1997-04-01

    This study was undertaken to determine the extent of adhesion of cysts and trophozoites of Acanthamoeba to worn disposable hydrogel lenses and to study the effect of time, lens material, and washing on the adhesion. Etafilcon A (58% water content) and Polymacon (38% water content) lenses worn on a 6 night extended wear basis and collected aseptically in PBS pH 7.2, were used for the study. Unworn lenses of the same materials were used as controls. Segments of lenses were incubated in Acanthamoeba suspension (cysts and trophozoites) and examined at 0, 5, and 24 hours, either washed or unwashed, for adherent Acanthamoeba. The amoebae adherent per square mm surface of the lens were enumerated. Levels of adhesion in various groups were compared using Wilcoxon sign rank test. At 0 hours, unwashed worn Polymacon lenses showed significantly greater adherence than Etafilcon A lenses compared to the controls (P = 0.0469). However, there was no difference at 5 and 24 hours exposure time between the lenses. At 24 hours the adhesion of Acanthamoeba was greater for washed worn lenses of both types compared to washed lenses of controls (P = 0.002, 0.012). Amoebae adhered with equal affinity to both types of lenses but adhered with greater affinity to worn lenses than unworn lenses. Adhesion of Acanthamoeba to worn disposable lenses may be a factor in the pathogenesis of Acanthamoeba keratitis in disposable lens wearers.

  11. The effects of structure anisotropy on lensing observables in an exact general relativistic setting for precision cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Troxel, M. A.; Ishak, Mustapha; Peel, Austin, E-mail: troxel@utdallas.edu, E-mail: mishak@utdallas.edu, E-mail: austin.peel@utdallas.edu [Department of Physics, The University of Texas at Dallas, Richardson, TX 75080 (United States)

    2014-03-01

    The study of relativistic, higher order, and nonlinear effects has become necessary in recent years in the pursuit of precision cosmology. We develop and apply here a framework to study gravitational lensing in exact models in general relativity that are not restricted to homogeneity and isotropy, and where full nonlinearity and relativistic effects are thus naturally included. We apply the framework to a specific, anisotropic galaxy cluster model which is based on a modified NFW halo density profile and described by the Szekeres metric. We examine the effects of increasing levels of anisotropy in the galaxy cluster on lensing observables like the convergence and shear for various lensing geometries, finding a strong nonlinear response in both the convergence and shear for rays passing through anisotropic regions of the cluster. Deviation from the expected values in a spherically symmetric structure are asymmetric with respect to path direction and thus will persist as a statistical effect when averaged over some ensemble of such clusters. The resulting relative difference in various geometries can be as large as approximately 2%, 8%, and 24% in the measure of convergence (1−κ) for levels of anisotropy of 5%, 10%, and 15%, respectively, as a fraction of total cluster mass. For the total magnitude of shear, the relative difference can grow near the center of the structure to be as large as 15%, 32%, and 44% for the same levels of anisotropy, averaged over the two extreme geometries. The convergence is impacted most strongly for rays which pass in directions along the axis of maximum dipole anisotropy in the structure, while the shear is most strongly impacted for rays which pass in directions orthogonal to this axis, as expected. The rich features found in the lensing signal due to anisotropic substructure are nearly entirely lost when one treats the cluster in the traditional FLRW lensing framework. These effects due to anisotropic structures are thus likely to

  12. Probing the dark side of the Universe with weak gravitational lensing effects

    International Nuclear Information System (INIS)

    Fu Li-Ping; Fan Zu-Hui

    2014-01-01

    Arising from gravitational deflections of light rays by large-scale structures in the Universe, weak-lensing effects have been recognized as one of the most important probes in cosmological studies. In this paper, we review the main progress in weak-lensing analyses, and discuss the challenges in future investigations aiming to understand the dark side of the Universe with unprecedented precisions. (invited reviews)

  13. Spatially Resolved Patchy Ly α Emission within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8

    Energy Technology Data Exchange (ETDEWEB)

    Bayliss, Matthew B.; Bordoloi, Rongmon [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Sharon, Keren; Runnoe, Jessie; Johnson, Traci; Paterno-Mahler, Rachel [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Acharyya, Ayan; Bian, Fuyan; Kewley, Lisa [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Gladders, Michael D. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Rigby, Jane R. [Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Dahle, Hakon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Florian, Michael, E-mail: mbayliss@mit.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2017-08-20

    We report the detection of extended Ly α emission from the host galaxy of SDSS J2222+2745, a strongly lensed quasar at z = 2.8. Spectroscopic follow-up clearly reveals extended Ly α in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens model to HST imaging and resolve spatial scales as small as ∼200 pc. In the source plane, we recover the host galaxy morphology to within a few hundred parsecs of the central AGN and map the extended Ly α emission to its physical origin on one side of the host galaxy at radii ∼0.5–2 kpc from the central AGN. There are clear morphological differences between the Ly α and rest-frame ultraviolet stellar continuum emission from the quasar host galaxy. Furthermore, the relative velocity profiles of quasar Ly α , host galaxy Ly α , and metal lines in outflowing gas reveal differences in the absorbing material affecting the AGN and host galaxy. These data indicate the presence of patchy local intervening gas in front of the central quasar and its host galaxy. This interpretation is consistent with the central luminous quasar being obscured across a substantial fraction of its surrounding solid angle, resulting in strong anisotropy in the exposure of the host galaxy to ionizing radiation from the AGN. This work demonstrates the power of strong-lensing-assisted studies to probe spatial scales that are currently inaccessible by other means.

  14. Effect of Unifocal versus Multifocal Lenses on Cervical Spine Posture in Patients with Presbyopia.

    Science.gov (United States)

    Abbas, Rami L; Houri, Mohamad T; Rayyan, Mohammad M; Hamada, Hamada Ahmad; Saab, Ibtissam M

    2018-04-04

    There are many environmental considerations which may or may not lead to the development of faulty cervical mechanics. The design of near vision lenses could contribute to the development of such cervical dysfunction and consequently neck pain. Decision making regarding proper type of lens prescription seems important for presbyopic individuals. To investigate the effect of unifocal and multifocal lenses on cervical posture. Thirty subjects (18 females and 12 males) participated in the study with an age range from 40 to 64 years. Each subject wore consequently both unifocal and multifocal lenses randomly while reading. Then lateral cervical spine X-ray films were taken for each subject during each lens wearing. X-ray films were analyzed with digital software (Autocad software, 2 D) to measure segmental angles of the cervical vertebrae (Occiput/C1, C1/C2, C2/C3, C3/C4, C4/C5, C5/C6, C6/C7, C3/C7, C0/C3, and occiput/C7). Higher significant extension angle in the segments C0/C7, C1/C2, C5/C6, C6/C7, and C3/C7 (p<0.05) during multifocal lenses wearing were observed in contrast with higher flexion angle between C3/C4 and C4/C5 (p<0.05) with unifocal lenses wear. Multifocal lens spectacles produces increased extension in the cervical vertebrae angles when compared with the use of unifocal lenses.

  15. Efficient simulation of autofluorescence effects in microscopic lenses

    DEFF Research Database (Denmark)

    Gross, Herbert; Rodenko, Olga; Esslinger, Moritz

    2015-01-01

    The use of fluorescence in microscopy is a well known technology today. Due to the autofluorescence of the materials of the optical system components, the contrast of the images is degraded. The calculation of autofluorescense usually is performed by brute force methods as volume scattering...... be performed properly. Some necessary approximations produce negligible errors. The improvement in run time is in the range of 104 . It is shown with some practical examples of microscopic lenses, that the results are comparable with conventional methods. The limitations and the consequences for questions...

  16. Optical effects of exposing intact human lenses to ultraviolet radiation and visible light

    DEFF Research Database (Denmark)

    Kessel, Line; Eskildsen, Lars Baunsgaard; Lundeman, Jesper Holm

    2011-01-01

    wavelength region of incoming visible light. The aim of the present study was to examine the optical effects on human lenses of short wavelength visible light and ultraviolet radiation. METHODS: Naturally aged human donor lenses were irradiated with UVA (355 nm), violet (400 and 405 nm) and green (532 nm......ABSTRACT: BACKGROUND: The human lens is continuously exposed to high levels of light. Ultraviolet radiation is believed to play a causative role in the development of cataract. In vivo, however, the lens is mainly exposed to visible light and the ageing lens absorbs a great part of the short....... RESULTS: Irradiation with high intensity lasers caused scattering lesions in the human lenses. These effects were more likely to be seen when using pulsed lasers because of the high pulse intensity. Prolonged irradiation with UVA led to photodarkening whereas no detrimental effects were observed after...

  17. Effective wavefront aberration measurement of spectacle lenses in as-worn status

    Science.gov (United States)

    Jia, Zhigang; Xu, Kai; Fang, Fengzhou

    2018-04-01

    An effective wavefront aberration analysis method for measuring spectacle lenses in as-worn status was proposed and verified using an experimental apparatus based on an eye rotation model. Two strategies were employed to improve the accuracy of measurement of the effective wavefront aberrations on the corneal sphere. The influences of three as-worn parameters, the vertex distance, pantoscopic angle, and face form angle, together with the eye rotation and corresponding incident beams, were objectively and quantitatively obtained. The experimental measurements of spherical single vision and freeform progressive addition lenses demonstrate the accuracy and validity of the proposed method and experimental apparatus, which provide a potential means of achieving supernormal vision correction with customization and personalization in optimizing the as-worn status-based design of spectacle lenses and evaluating their manufacturing and imaging qualities.

  18. Effects of Corneal Scars and Their Treatment With Rigid Contact Lenses on Quality of Vision

    NARCIS (Netherlands)

    de Jong, Bram; van der Meulen, Ivanka J E; van Vliet, Johannes M J; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P; van den Berg, Thomas J T P

    2018-01-01

    OBJECTIVES: To study the effects of corneal scars and the treatment of these scars with rigid gas-permeable (RGP) contact lenses on quality of vision including straylight. Visual effects were related to scar characteristics such as size and grade. METHODS: Straylight and best-corrected visual acuity

  19. Effects of Corneal Scars and Their Treatment With Rigid Contact Lenses on Quality of Vision

    NARCIS (Netherlands)

    de Jong, Bram; van der Meulen, Ivanka J. E.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; van den Berg, Thomas J. T. P.

    2017-01-01

    To study the effects of corneal scars and the treatment of these scars with rigid gas-permeable (RGP) contact lenses on quality of vision including straylight. Visual effects were related to scar characteristics such as size and grade. Straylight and best-corrected visual acuity were measured in 23

  20. Effect of four different intraocular lenses on posterior capsule opacification.

    Science.gov (United States)

    Duman, Rahmi; Karel, Fatih; Özyol, Pelin; Ateş, Can

    2015-01-01

    To evaluate the impact of 4 different intraocular lenses (IOLs) on posterior capsule opacification (PCO) by comparing the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy rates. This retrospective study included 4970 eyes of 4013 cataract patients who underwent phacoemulsification and IOL implantation between January 2000 and January 2008 by the same surgeon at one clinic. Four different IOLs were assessed. The outcome parameter was the incidence of Nd:YAG laser posterior capsulotomies. An Nd:YAG laser posterior capsulotomy was performed in 153 (3.07%) of the 4970 eyes. The mean follow-up time was 84mo for all of the IOL groups. The percentage of eyes developing PCO was significantly greater for the acrylic hydrophilic IOLs than for the hydrophobic IOLs, although eyes with acrylic hydrophilic IOLs did not require Nd:YAG laser capsulotomy as soon as eyes with acrylic hydrophobic IOLs. There was no difference between the long-term PCO rates when 1- and 3-piece acrylic hydrophobic IOLs were compared or when IOLs made of the same material but with different haptic angles were compared. In this study, eyes with acrylic hydrophilic IOLs were more likely to develop PCO than those with acrylic hydrophobic IOLs. The lens design (1-piece versus 3-piece and varying haptic angles) did not affect the PCO rate.

  1. Differential adherence of Acanthamoeba to contact lenses: effects of material characteristics.

    Science.gov (United States)

    Seal, D V; Bennett, E S; McFadyen, A K; Todd, E; Tomlinson, A

    1995-01-01

    Acanthamoeba-associated keratitis occurs most often in contact lens wearers. The contact lens material may affect its ability to act as a mechanical vector, permitting transfer of viable amoebae from the storage case to the corneal surface. The purpose of this study was to investigate the effects of ionicity and water content on the comparative quantitative adherence of Acanthamoeba trophozoites and cysts to new, unworn hydrogel contact lenses and rigid gas-permeable contact lens materials. Sixteen quarter segments of each of 8 types of unworn hydrogel lenses representative of FDA groups 1 to 4 were exposed to freshly prepared cultures of either trophozoites or cysts of A. castellanii or A. polyphaga for 1.5 h, and then washed. Three types of rigid lens button were similarly exposed to A. castellanii trophozoites or cysts. Adherent trophozoites and cysts were then enumerated. All hydrogel lenses showed binding of both trophozoites and cysts, with the former predominating in every case. It was primarily the ionic nature of a lens surface and secondly its water content that was associated with increased quantitative adherence of Acanthamoeba. Neither form of the amoebae bound to any of the hard lens buttons. Greater relative potential exists for contamination of ionic and high-water content hydrogels by Acanthamoeba. This combination may influence mechanical transmission of the protozoon to the corneal surface. Adherence to hard lenses (as buttons) did not occur if a postincubation wash step was performed.

  2. Finding quantum effects in strong classical potentials

    Science.gov (United States)

    Hegelich, B. Manuel; Labun, Lance; Labun, Ou Z.

    2017-06-01

    The long-standing challenge to describing charged particle dynamics in strong classical electromagnetic fields is how to incorporate classical radiation, classical radiation reaction and quantized photon emission into a consistent unified framework. The current, semiclassical methods to describe the dynamics of quantum particles in strong classical fields also provide the theoretical framework for fundamental questions in gravity and hadron-hadron collisions, including Hawking radiation, cosmological particle production and thermalization of particles created in heavy-ion collisions. However, as we show, these methods break down for highly relativistic particles propagating in strong fields. They must therefore be improved and adapted for the description of laser-plasma experiments that typically involve the acceleration of electrons. Theory developed from quantum electrodynamics, together with dedicated experimental efforts, offer the best controllable context to establish a robust, experimentally validated foundation for the fundamental theory of quantum effects in strong classical potentials.

  3. Optical effects of exposing intact human lenses to ultraviolet radiation and visible light.

    Science.gov (United States)

    Kessel, Line; Eskildsen, Lars; Lundeman, Jesper Holm; Jensen, Ole Bjarlin; Larsen, Michael

    2011-12-30

    The human lens is continuously exposed to high levels of light. Ultraviolet radiation is believed to play a causative role in the development of cataract. In vivo, however, the lens is mainly exposed to visible light and the ageing lens absorbs a great part of the short wavelength region of incoming visible light. The aim of the present study was to examine the optical effects on human lenses of short wavelength visible light and ultraviolet radiation. Naturally aged human donor lenses were irradiated with UVA (355 nm), violet (400 and 405 nm) and green (532 nm) lasers. The effect of irradiation was evaluated qualitatively by photography and quantitatively by measuring the direct transmission before and after irradiation. Furthermore, the effect of pulsed and continuous laser systems was compared as was the effect of short, intermediate and prolonged exposures. Irradiation with high intensity lasers caused scattering lesions in the human lenses. These effects were more likely to be seen when using pulsed lasers because of the high pulse intensity. Prolonged irradiation with UVA led to photodarkening whereas no detrimental effects were observed after irradiation with visible light. Irradiation with visible light does not seem to be harmful to the human lens except if the lens is exposed to laser irradiances that are high enough to warrant thermal protein denaturation that is more readily seen using pulsed laser systems.

  4. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

    OpenAIRE

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-01

    Background In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. Methods A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3?mm of pupil diameter and...

  5. Optical effects of exposing intact human lenses to ultraviolet radiation and visible light

    DEFF Research Database (Denmark)

    Kessel, Line; Eskildsen, Lars; Lundeman, Jesper Holm

    2011-01-01

    BACKGROUND: The human lens is continuously exposed to high levels of light. Ultraviolet radiation is believed to play a causative role in the development of cataract. In vivo, however, the lens is mainly exposed to visible light and the ageing lens absorbs a great part of the short wavelength...... region of incoming visible light. The aim of the present study was to examine the optical effects on human lenses of short wavelength visible light and ultraviolet radiation. METHODS: Naturally aged human donor lenses were irradiated with UVA (355 nm), violet (400 and 405 nm) and green (532 nm) lasers...... with visible light. CONCLUSIONS: Irradiation with visible light does not seem to be harmful to the human lens except if the lens is exposed to laser irradiances that are high enough to warrant thermal protein denaturation that is more readily seen using pulsed laser systems....

  6. Optical effects of exposing intact human lenses to ultraviolet radiation and visible light

    DEFF Research Database (Denmark)

    Kessel, Line; Eskildsen, Lars Baunsgaard; Lundeman, Jesper Holm

    2011-01-01

    ABSTRACT: BACKGROUND: The human lens is continuously exposed to high levels of light. Ultraviolet radiation is believed to play a causative role in the development of cataract. In vivo, however, the lens is mainly exposed to visible light and the ageing lens absorbs a great part of the short...... wavelength region of incoming visible light. The aim of the present study was to examine the optical effects on human lenses of short wavelength visible light and ultraviolet radiation. METHODS: Naturally aged human donor lenses were irradiated with UVA (355 nm), violet (400 and 405 nm) and green (532 nm...... irradiation with visible light. CONCLUSIONS: Irradiation with visible light does not seem to be harmful to the human lens except if the lens is exposed to laser irradiances that are high enough to warrant thermal protein denaturation that is more readily seen using pulsed laser systems....

  7. Wormhole effect in a strong topological insulator

    Science.gov (United States)

    Rosenberg, G.; Guo, H.-M.; Franz, M.

    2010-07-01

    An infinitely thin solenoid carrying magnetic flux Φ (a “Dirac string”) inserted into an ordinary band insulator has no significant effect on the spectrum of electrons. In a strong topological insulator, remarkably, such a solenoid carries protected gapless one-dimensional fermionic modes when Φ=hc/2e . These modes are spin-filtered and represent a distinct bulk manifestation of the topologically nontrivial insulator. We establish this “wormhole” effect by both general qualitative considerations and by numerical calculations within a minimal lattice model. We also discuss the possibility of experimental observation of a closely related effect in artificially engineered nanostructures.

  8. The effect of Acanthamoeba concentration on adherence to four types of unworn soft contact lenses.

    Science.gov (United States)

    Kelly, L D; Xu, L

    1995-01-01

    Contact lens wear is a predominant risk factor for Acanthamoeba keratitis. The exact nature of the relationship between organism concentration and contact lens adherence is poorly understood. We investigated the effect of Acanthamoeba inoculation concentration on adherence to four categories of contact lenses of varying polymers and water content. Acanthamoeba polyphaga was harvested in log growth phase at 5 days subculture and suspended in PBS at concentrations of 1 x 10(2), 10(3), 10(4), 10(5), and 10(6) organisms/mL (trophozoite:cyst ratio 90:10 +/- 2). Sterile unworn polymacon, etafilcon, lidofilcon, and bufilcon contact lens segments were exposed to Acanthamoeba for 2 hours. Acanthamoeba adherence was quantified using phase contrast microscopy. For all lens types, trophozoite adherence increased as the concentration of inoculum increased, but the relationship was not directly proportional. In all cases the minimal adherence was observed at 10(2). Trophozoite adherence increased disproportionate to cysts for all contact lens types. The greatest adherence was to lidofilcon lenses. At all concentrations adherence was greater to lidofilcon than etafilcon or polymacon, and greater to bufilcon than etafilcon or polymacon at the P < 0.01 level. Adherence was significantly greater to lidofilcon than bufilcon only at 1 x 10(5) and 10(6); P < 0.05 (ANOVA). This study suggests that adherence of A. polyphaga to contact lenses increases with the number of organisms in the inoculum, but the relationship is not directly proportional. The number of adherent organisms varies by contact lens type, with the greatest adherence to lidofilcon and the least to etafilcon lenses.

  9. Core or Cusps: The Central Dark Matter Profile of a Strong Lensing Cluster with a Bright Central Image at Redshift 1

    Energy Technology Data Exchange (ETDEWEB)

    Collett, Thomas E.; Buckley-Geer, Elizabeth; Lin, Huan; Bacon, David; Nichol, Robert C.; Nord, Brian; Morice-Atkinson, Xan; Amara, Adam; Birrer, Simon; Kuropatkin, Nikolay; More, Anupreeta; Papovich, Casey; Romer, Kathy K.; Tessore, Nicolas; Abbott, Tim M. C.; Allam, Sahar; Annis, James; Benoit-Lévy, Aurlien; Brooks, David; Burke, David L.; Carrasco Kind, Matias; Castander, Francisco Javier J.; D’Andrea, Chris B.; da Costa, Luiz N.; Desai, Shantanu; Diehl, H. Thomas; Doel, Peter; Eifler, Tim F.; Flaugher, Brenna; Frieman, Josh; Gerdes, David W.; Goldstein, Daniel A.; Gruen, Daniel; Gschwend, Julia; Gutierrez, Gaston; James, David J.; Kuehn, Kyler; Kuhlmann, Steve; Lahav, Ofer; Li, Ting S.; Lima, Marcos; Maia, Marcio A. G.; March, Marisa; Marshall, Jennifer L.; Martini, Paul; Melchior, Peter; Miquel, Ramon; Plazas, Andrs A.; Rykoff, Eli S.; Sanchez, Eusebio; Scarpine, Vic; Schindler, Rafe; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Smith, Mathew; Sobreira, Flavia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Tucker, Douglas L.; Walker, Alistair R.

    2017-07-10

    We report on SPT-CLJ2011-5228, a giant system of arcs created by a cluster at $z=1.06$. The arc system is notable for the presence of a bright central image. The source is a Lyman Break galaxy at $z_s=2.39$ and the mass enclosed within the 14 arc second radius Einstein ring is $10^{14.2}$ solar masses. We perform a full light profile reconstruction of the lensed images to precisely infer the parameters of the mass distribution. The brightness of the central image demands that the central total density profile of the lens be shallow. By fitting the dark matter as a generalized Navarro-Frenk-White profile---with a free parameter for the inner density slope---we find that the break radius is $270^{+48}_{-76}$ kpc, and that the inner density falls with radius to the power $-0.38\\pm0.04$ at 68 percent confidence. Such a shallow profile is in strong tension with our understanding of relaxed cold dark matter halos; dark matter only simulations predict the inner density should fall as $r^{-1}$. The tension can be alleviated if this cluster is in fact a merger; a two halo model can also reconstruct the data, with both clumps (density going as $r^{-0.8}$ and $r^{-1.0}$) much more consistent with predictions from dark matter only simulations. At the resolution of our Dark Energy Survey imaging, we are unable to choose between these two models, but we make predictions for forthcoming Hubble Space Telescope imaging that will decisively distinguish between them.

  10. Strong curvature effects in Neumann wave problems

    DEFF Research Database (Denmark)

    Willatzen, Morten; Pors, A.; Gravesen, Jens

    2012-01-01

    Waveguide phenomena play a major role in basic sciences and engineering. The Helmholtz equation is the governing equation for the electric field in electromagnetic wave propagation and the acoustic pressure in the study of pressure dynamics. The Schro¨dinger equation simplifies to the Helmholtz...... equation for a quantum-mechanical particle confined by infinite barriers relevant in semiconductor physics. With this in mind and the interest to tailor waveguides towards a desired spectrum and modal pattern structure in classical structures and nanostructures, it becomes increasingly important...... to understand the influence of curvature effects in waveguides. In this work, we demonstrate analytically strong curvature effects for the eigenvalue spectrum of the Helmholtz equation with Neumann boundary conditions in cases where the waveguide cross section is a circular sector. It is found that the linear...

  11. Strong curvature effects in Neumann wave problems

    International Nuclear Information System (INIS)

    Willatzen, M.; Pors, A.; Gravesen, J.

    2012-01-01

    Waveguide phenomena play a major role in basic sciences and engineering. The Helmholtz equation is the governing equation for the electric field in electromagnetic wave propagation and the acoustic pressure in the study of pressure dynamics. The Schrödinger equation simplifies to the Helmholtz equation for a quantum-mechanical particle confined by infinite barriers relevant in semiconductor physics. With this in mind and the interest to tailor waveguides towards a desired spectrum and modal pattern structure in classical structures and nanostructures, it becomes increasingly important to understand the influence of curvature effects in waveguides. In this work, we demonstrate analytically strong curvature effects for the eigenvalue spectrum of the Helmholtz equation with Neumann boundary conditions in cases where the waveguide cross section is a circular sector. It is found that the linear-in-curvature contribution originates from parity symmetry breaking of eigenstates in circular-sector tori and hence vanishes in a torus with a complete circular cross section. The same strong curvature effect is not present in waveguides subject to Dirichlet boundary conditions where curvature contributions contribute to second-order in the curvature only. We demonstrate this finding by considering wave propagation in a circular-sector torus corresponding to Neumann and Dirichlet boundary conditions, respectively. Results for relative eigenfrequency shifts and modes are determined and compared with three-dimensional finite element method results. Good agreement is found between the present analytical method using a combination of differential geometry with perturbation theory and finite element results for a large range of curvature ratios.

  12. Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z 2-4 as probed by multi-J CO lines

    Science.gov (United States)

    Yang, C.; Omont, A.; Beelen, A.; Gao, Y.; van der Werf, P.; Gavazzi, R.; Zhang, Z.-Y.; Ivison, R.; Lehnert, M.; Liu, D.; Oteo, I.; González-Alfonso, E.; Dannerbauer, H.; Cox, P.; Krips, M.; Neri, R.; Riechers, D.; Baker, A. J.; Michałowski, M. J.; Cooray, A.; Smail, I.

    2017-12-01

    We present the IRAM-30 m observations of multiple-J CO (Jup mostly from 3 up to 8) and [C I](3P2 → 3P1) ([C I](2-1) hereafter) line emission in a sample of redshift 2-4 submillimeter galaxies (SMGs). These SMGs are selected among the brightest-lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Forty-seven CO lines and 7 [C I](2-1) lines have been detected in 15 lensed SMGs. A non-negligible effect of differential lensing is found for the CO emission lines, which could have caused significant underestimations of the linewidths, and hence of the dynamical masses. The CO spectral line energy distributions (SLEDs), peaking around Jup 5-7, are found to be similar to those of the local starburst-dominated ultra-luminous infrared galaxies and of the previously studied SMGs. After correcting for lensing amplification, we derived the global properties of the bulk of molecular gas in the SMGs using non-LTE radiative transfer modelling, such as the molecular gas density nH2 102.5-104.1 cm-3 and the kinetic temperature Tk 20-750 K. The gas thermal pressure Pth ranging from 105 K cm-3 to 106 K cm-3 is found to be correlated with star formation efficiency. Further decomposing the CO SLEDs into two excitation components, we find a low-excitation component with nH2 102.8-104.6 cm-3 and Tk 20-30 K, which is less correlated with star formation, and a high-excitation one (nH2 102.7-104.2 cm-3, Tk 60-400 K) which is tightly related to the on-going star-forming activity. Additionally, tight linear correlations between the far-infrared and CO line luminosities have been confirmed for the Jup ≥ 5 CO lines of these SMGs, implying that these CO lines are good tracers of star formation. The [C I](2-1) lines follow the tight linear correlation between the luminosities of the [C I](2-1) and the CO(1-0) line found in local starbursts, indicating that [C I] lines could serve as good total molecular gas mass tracers for high-redshift SMGs as well

  13. EDITORIAL: Focus on Gravitational Lensing

    Science.gov (United States)

    Jain, Bhuvnesh

    2007-11-01

    Gravitational lensing emerged as an observational field following the 1979 discovery of a doubly imaged quasar lensed by a foreground galaxy. In the 1980s and '90s dozens of other multiply imaged systems were observed, as well as time delay measurements, weak and strong lensing by galaxies and galaxy clusters, and the discovery of microlensing in our galaxy. The rapid pace of advances has continued into the new century. Lensing is currently one of best techniques for finding and mapping dark matter over a wide range of scales, and also addresses broader cosmological questions such as understanding the nature of dark energy. This focus issue of New Journal of Physics presents a snapshot of current research in some of the exciting areas of lensing. It provides an occasion to look back at the advances of the last decade and ahead to the potential of the coming years. Just about a decade ago, microlensing was discovered through the magnification of stars in our galaxy by invisible objects with masses between that of Jupiter and a tenth the mass of the Sun. Thus a new component of the mass of our galaxy, dubbed MACHOs, was established (though a diffuse, cold dark matter-like component is still needed to make up most of the galaxy mass). More recently, microlensing led to another exciting discovery—of extra-solar planets with masses ranging from about five times that of Earth to that of Neptune. We can expect many more planets to be discovered through ongoing surveys. Microlensing is the best technique for finding Earth mass planets, though it is not as productive overall as other methods and does not allow for follow up observations. Beyond planet hunting, microlensing has enabled us to observe previously inaccessible systems, ranging from the surfaces of other stars to the accretion disks around the black holes powering distant quasars. Galaxies and galaxy clusters at cosmological distances can produce dramatic lensing effects: multiple images of background galaxies

  14. Reliability of power profiles measured on NIMO TR1504 (Lambda-X) and effects of lens decentration for single vision, bifocal and multifocal contact lenses.

    Science.gov (United States)

    Kim, Eon; Bakaraju, Ravi C; Ehrmann, Klaus

    2016-01-01

    To evaluate the repeatability of power profiles measured on NIMO TR1504 (Lambda-X, Belgium) and investigate the effects of lens decentration on the power profiles for single vision (SV), bifocal (BF) and multifocal (MF) contact lenses. Accuracy of the sphere power was evaluated using single vision BK-7 calibration glass lenses of six minus and six plus powers. Three SV and four BF/MF contact lenses - three lenses each, were measured five times to calculate the coefficients of repeatability (COR) of the instrument. The COR was computed for each chord position, lens design, prescription power and operator. One lens from each type was measured with a deliberate decentration up to ±0.5mm in 0.1mm steps. For all lenses, the COR varied across different regions of the half-chord position. In general, SV lenses showed lower COR compared to the BF/MF group lenses. There were no noticeable trends of COR between prescription powers for SV and BF/MF lenses. The shape of the power profiles was not affected when lenses were deliberately decentered for all SV and PureVision MF lenses. However, for Acuvue BF lenses, the peak to trough amplitude of the power profiles flattened up to 1.00D. The COR across the half-chord of the optic zone diameter was mostly within clinical relevance except for the central 0.5mm half-chord position. COR were dependent on the lens type, whereby BF/MF group produced higher COR than SV lenses. The effects of deliberate decentration on the shape of power profiles were pronounced for lenses where the profiles had sharp transitions of power. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  15. Distinguishing f(R) theories from general relativity by gravitational lensing effect

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongguang [Beijing Normal University, Department of Physics, Beijing (China); Aix Marseille Universite et Universite de Toulon, Centre de Physique Theorique (UMR 7332), Marseille (France); Wang, Xin; Li, Haida; Ma, Yongge [Beijing Normal University, Department of Physics, Beijing (China)

    2017-11-15

    The post-Newtonian formulation of a general class of f(R) theories is set up in a third-order approximation. It turns out that the information of a specific form of f(R) gravity is encoded in the Yukawa potential, which is contained in the perturbative expansion of the metric components. Although the Yukawa potential is canceled in the second-order expression of the effective refraction index of light, detailed analysis shows that the difference of the lensing effect between the f(R) gravity and general relativity does appear at the third order when √(f''(0)/f{sup '}(0)) is larger than the distance d{sub 0} to the gravitational source. However, the difference between these two kinds of theories will disappear in the axially symmetric spacetime region. Therefore only in very rare case the f(R) theories are distinguishable from general relativity by gravitational lensing effect in a third-order post-Newtonian approximation. (orig.)

  16. The effect of concurrent Pseudomonas or Xanthomonas exposure on adherence of Acanthamoeba castellanii to soft contact lenses.

    Science.gov (United States)

    Kelly, L D; Xu, L

    1996-05-01

    Approximately 85% of Acanthamoeba-contaminated contact lens systems in asymptomatic patients have concurrent bacterial contamination. Pseudomonas aeruginosa and Xanthomonas maltophilia are common contact lens contaminants; we investigated the effect of coincubation of Acanthamoeba adherence to contact lenses. A. castellanii, 1 x 10(5) organisms/ml, was coincubated with P. aeruginosa or X. maltophilia, 1 x 10(8) CFU/ml in phosphate-buffered saline. Sterile, unworn polymacon, etafilcon A or lidofilcon contact lens were investigated. The experimental groups were: (I) lenses exposed to bacteria for 1 h, then Acanthamoeba for 2 h; (II) lenses exposed concurrently to bacteria and Acanthamoeba for 2 h; (III) Acanthamoeba coincubated with bacteria for 24 h, then lenses exposed for 2 h; (IV) lenses exposed to Acanthamoeba for 2 h (control). For all experimental groups, Acanthamoeba adherence was greater to lidofilcon than to polymacon and etafilcon. For both P. aeruginosa and X. maltophilia, neither group I nor group II displayed greater Acanthamoeba adherence than group IV. Group III exhibited significantly less adherence than group IV for lidofilcon and polymacon. The decrease in group III adherence reflected an overall decrease in Acanthamoeba trophozoite concentration. Short bacteria/Acanthamoeba coincubation times did not result in increased Acanthamoeba adherence. Twenty-four-hour coincubation resulted in decreased adherence for Pseudomonas and unchanged adherence rates for Xanthomonas. This model suggests that Pseudomonas or Xanthomonas co-contamination does not necessarily facilitate quantitative Acanthamoeba contact lens adherence.

  17. Mask effects on cosmological studies with weak-lensing peak statistics

    International Nuclear Information System (INIS)

    Liu, Xiangkun; Pan, Chuzhong; Fan, Zuhui; Wang, Qiao

    2014-01-01

    With numerical simulations, we analyze in detail how the bad data removal, i.e., the mask effect, can influence the peak statistics of the weak-lensing convergence field reconstructed from the shear measurement of background galaxies. It is found that high peak fractions are systematically enhanced because of the presence of masks; the larger the masked area is, the higher the enhancement is. In the case where the total masked area is about 13% of the survey area, the fraction of peaks with signal-to-noise ratio ν ≥ 3 is ∼11% of the total number of peaks, compared with ∼7% of the mask-free case in our considered cosmological model. This can have significant effects on cosmological studies with weak-lensing convergence peak statistics, inducing a large bias in the parameter constraints if the effects are not taken into account properly. Even for a survey area of 9 deg 2 , the bias in (Ω m , σ 8 ) is already intolerably large and close to 3σ. It is noted that most of the affected peaks are close to the masked regions. Therefore, excluding peaks in those regions in the peak statistics can reduce the bias effect but at the expense of losing usable survey areas. Further investigations find that the enhancement of the number of high peaks around the masked regions can be largely attributed to the smaller number of galaxies usable in the weak-lensing convergence reconstruction, leading to higher noise than that of the areas away from the masks. We thus develop a model in which we exclude only those very large masks with radius larger than 3' but keep all the other masked regions in peak counting statistics. For the remaining part, we treat the areas close to and away from the masked regions separately with different noise levels. It is shown that this two-noise-level model can account for the mask effect on peak statistics very well, and the bias in cosmological parameters is significantly reduced if this model is applied in the parameter fitting.

  18. H0LiCOW - V. New COSMOGRAIL time delays of HE 0435-1223: H0 to 3.8 per cent precision from strong lensing in a flat ΛCDM model

    Science.gov (United States)

    Bonvin, V.; Courbin, F.; Suyu, S. H.; Marshall, P. J.; Rusu, C. E.; Sluse, D.; Tewes, M.; Wong, K. C.; Collett, T.; Fassnacht, C. D.; Treu, T.; Auger, M. W.; Hilbert, S.; Koopmans, L. V. E.; Meylan, G.; Rumbaugh, N.; Sonnenfeld, A.; Spiniello, C.

    2017-03-01

    We present a new measurement of the Hubble Constant H0 and other cosmological parameters based on the joint analysis of three multiply imaged quasar systems with measured gravitational time delays. First, we measure the time delay of HE 0435-1223 from 13-yr light curves obtained as part of the COSMOGRAIL project. Companion papers detail the modelling of the main deflectors and line-of-sight effects, and how these data are combined to determine the time-delay distance of HE 0435-1223. Crucially, the measurements are carried out blindly with respect to cosmological parameters in order to avoid confirmation bias. We then combine the time-delay distance of HE 0435-1223 with previous measurements from systems B1608+656 and RXJ1131-1231 to create a Time Delay Strong Lensing probe (TDSL). In flat Λ cold dark matter (ΛCDM) with free matter and energy density, we find H0 =71.9^{+2.4}_{-3.0} {km s^{-1} Mpc^{-1}} and Ω _{Λ }=0.62^{+0.24}_{-0.35}. This measurement is completely independent of, and in agreement with, the local distance ladder measurements of H0. We explore more general cosmological models combining TDSL with other probes, illustrating its power to break degeneracies inherent to other methods. The joint constraints from TDSL and Planck are H0 = 69.2_{-2.2}^{+1.4} {km s^{-1} Mpc^{-1}}, Ω _{Λ }=0.70_{-0.01}^{+0.01} and Ω _k=0.003_{-0.006}^{+0.004} in open ΛCDM and H0 =79.0_{-4.2}^{+4.4} {km s^{-1} Mpc^{-1}}, Ω _de=0.77_{-0.03}^{+0.02} and w=-1.38_{-0.16}^{+0.14} in flat wCDM. In combination with Planck and baryon acoustic oscillation data, when relaxing the constraints on the numbers of relativistic species we find Neff = 3.34_{-0.21}^{+0.21} in NeffΛCDM and when relaxing the total mass of neutrinos we find Σmν ≤ 0.182 eV in mνΛCDM. Finally, in an open wCDM in combination with Planck and cosmic microwave background lensing, we find H0 =77.9_{-4.2}^{+5.0} {km s^{-1} Mpc^{-1}}, Ω _de=0.77_{-0.03}^{+0.03}, Ω _k=-0.003_{-0.004}^{+0.004} and w=-1.37_{-0.23}^{+0.18}.

  19. Gravitational lensing

    CERN Document Server

    Dodelson, Scott

    2017-01-01

    Gravitational lensing is a consequence of general relativity, where the gravitational force due to a massive object bends the paths of light originating from distant objects lying behind it. Using very little general relativity and no higher level mathematics, this text presents the basics of gravitational lensing, focusing on the equations needed to understand the phenomena. It then applies them to a diverse set of topics, including multiply imaged objects, time delays, extrasolar planets, microlensing, cluster masses, galaxy shape measurements, cosmic shear, and lensing of the cosmic microwave background. This approach allows undergraduate students and others to get quickly up to speed on the basics and the important issues. The text will be especially relevant as large surveys such as LSST and Euclid begin to dominate the astronomical landscape. Designed for a one semester course, it is accessible to anyone with two years of undergraduate physics background.

  20. Bacterial transmission from lens storage cases to contact lenses - Effects of lens care solutions and silver impregnation of cases

    NARCIS (Netherlands)

    Vermeltfoort, Pit B. J.; Hooymans, Johanna M. M.; Busscher, Henk J.; van der Mei, Henny C.

    2008-01-01

    The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For

  1. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...... plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning....... The sample size in transition is relatively large and easily accessible in experiments, making our understanding of size dependence11, 12, 13, 14, 15, 16, 17 relevant for applications....

  2. Acoustic lenses

    International Nuclear Information System (INIS)

    Kittmer, C.A.

    1983-03-01

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  3. The Sloan Lens ACS Survey. XI. Beyond Hubble Resolution : Size, Luminosity, and Stellar Mass of Compact Lensed Galaxies at Intermediate Redshift

    NARCIS (Netherlands)

    Newton, Elisabeth R.; Marshall, Philip J.; Treu, Tommaso; Auger, Matthew W.; Gavazzi, Raphaeel; Bolton, Adam S.; Koopmans, Leon V. E.; Moustakas, Leonidas A.

    We exploit the strong lensing effect to explore the properties of intrinsically faint and compact galaxies at intermediate redshift (z(s) similar or equal to 0.4-0.8) at the highest possible resolution at optical wavelengths. Our sample consists of 46 strongly lensed emission line galaxies (ELGs)

  4. Gravitational lenses and cosmological evolution

    International Nuclear Information System (INIS)

    Peacock, J.A.

    1982-01-01

    The effect of gravitational lensing on the apparent cosmological evolution of extragalactic radio sources is investigated. Models for a lens population consisting of galaxies and clusters of galaxies are constructed and used to calculate the distribution of amplification factors caused by lensing. Although many objects at high redshifts are predicted to have flux densities altered by 10 to 20 per cent relative to a homogeneous universe, flux conservation implies that de-amplification is as common as amplification. The effects on cosmological evolution as inferred from source counts and redshift data are thus relatively small; the slope of the counts is not large enough for intrinsically rare lensing events of high amplitude to corrupt observed samples. Lensing effects may be of greater importance for optically selected quasars, where lenses of mass as low as approximately 10 -4 solar mass can cause large amplifications. (author)

  5. Gravitational lenses and. cosmological evolution

    Science.gov (United States)

    Peacock, J. A.

    1982-06-01

    The effect of gravitational lensing on the apparent evolution of extragalactic radio sources is investigated. Models for a lens population consisting of galaxies and clusters of galaxies are constructed used to calculate the distribution of amplification factors caused by lensing ,. Although many objects at high redshifts are predicted to have flux densities altered by 10-20 per cent relative to a homogeneous universe, flux conservation implies that de-amplification is as common as amplification. The effect on cosmological evolution as inferred from source counts and redshift data are thus relatively small; the slope of the counts is not large enough for intrinsically rare lensing events of high amplitude to corrupt observed sample Lensing effects may be of greater importance for optically selected quasar where lenses of mass as low as ˜10-4 Msun can cause large amplifications.

  6. Strong coupling effects in hybrid plexitonic systems

    Science.gov (United States)

    Melnikau, Dzmitry; Esteban, Ruben; Govyadinov, Alexander A.; Savateeva, Diana; Simon, Thomas; Sánchez-Iglesias, Ana; Grzelczak, Marek; Schmidt, Mikolaj K.; Urban, Alexander S.; Liz-Marzán, Luis M.; Feldmann, Jochen; Aizpurua, Javier; Rakovich, Yury P.

    2017-08-01

    We investigated the interactions between localized plasmons in gold nanorods and excitons in J-aggregates and were able to track an anticrossing behavior of the hybridized modes both in the extinction and in the photoluminescence spectra of this hybrid system. We identified the nonlinear optical behavior of this system by transient absorption spectroscopy. Finally using magnetic circular dichroism spectroscopy we showed that nonmagnetic organic molecules exhibit magnetooptical response due to binding to a plasmonic nanoparticles. In our experiments we also studied the effect of detuning as well as the effect of off- and on resonance excitation on the hybrid states

  7. Periodic self-lensing from accreting massive black hole binaries

    Science.gov (United States)

    D'Orazio, Daniel J.; Di Stefano, Rosanne

    2018-03-01

    Nearly 150 massive black hole binary (MBHB) candidates at sub-pc orbital separations have been reported in recent literature. Nevertheless, the definitive detection of even a single such object remains elusive. If at least one of the black holes is accreting, the light emitted from its accretion disc will be lensed by the other black hole for binary orbital inclinations near to the line of sight. This binary self-lensing could provide a unique signature of compact MBHB systems. We show that, for MBHBs with masses in the range 106-1010 M⊙ and with orbital periods less than ˜10 yr, strong lensing events should occur in one to 10s of per cent of MBHB systems that are monitored for an entire orbit. Lensing events will last from days for the less massive, shorter period MBHBs to a year for the most massive ˜10 year orbital period MBHBs. At small inclinations of the binary orbit to the line of sight, lensing must occur and will be accompanied by periodicity due to the relativistic Doppler boost. Flares at the same phase as the otherwise average flux of the Doppler modulation would be a smoking gun signature of self-lensing and can be used to constrain binary parameters. For MBHBs with separation ≳100 Schwarzschild radii, we show that finite-sized source effects could serve as a probe of MBH accretion disc structure. Finally, we stress that our lensing probability estimate implies that ˜10 of the known MBHB candidates identified through quasar periodicity should exhibit strong lensing flares.

  8. The effects of camera lenses and dental specialties on the perception of smile esthetics.

    Science.gov (United States)

    Sajjadi, Seyed Hadi; Khosravanifard, Behnam; Esmaeilpour, Mozhgan; Rakhshan, Vahid; Moazzami, Fatemeh

    2015-01-01

    The purpose of this study was to investigate whether different camera lenses and dental specialties can affect the perception of smile esthetics. In the first phase of this study, 40 female smile photographs (taken from dental students) were evaluated by six orthodontists, three specialists in restorative dentistry, and three prosthodontists to select the most beautiful smiles. The 20 students with the best smile ranks were again photographed in standard conditions, but this time with two different lenses: Regular and then macro lenses. Each referee evaluated the beauty of the smiles on a visual analog scale. The referees were blinded of the type of lenses, and the images were all coded. The data were analyzed using two-way analysis of variance (ANOVA), Kruskal-Wallis and Mann-Whitney U-tests (alpha = 0.05, alpha = 0.0167). The lenses led to similar scores of beauty perception (Mann-Whitney P = 0.8). There was no difference between subjective beauty perception of specialties (Kruskal-Wallis P = 0.6). Two-way ANOVA indicated no significant role for lenses (P = 0.1750), specialties (P = 0.7677), or their interaction (P = 0.7852). The photographs taken by a regular lens and then digitally magnified can be as appealing as close-up photographs taken by a macro lens. Experts in different specialties (orthodontics, prosthodontics, and restorative dentistry) showed similar subjective judgments of smile beauty.

  9. Disorder effects in strongly correlated uranium compounds

    International Nuclear Information System (INIS)

    Suellow, S.; Maple, M.B.; Tomuta, D.; Nieuwenhuys, G.J.; Menovsky, A.A.; Mydosh, J.A.; Chau, R.

    2001-01-01

    Moderate levels of crystallographic disorder can dramatically affect the ground-state properties of heavy fermion compounds. In particular, the role of disorder close to a quantum critical point has been investigated in detail. However, crystallographic disorder is equally effective in altering the properties of magnetically ordered heavy fermion compounds like URh 2 Ge 2 , where disorder-induced spin-glass behavior has been observed. In this system, moreover, the magnetic ground state can be tuned from a spin-glass to a long-range ordered antiferromagnetic one by means of an annealing treatment. The transformation of the magnetic state is accompanied by a transition in the transport properties from 'quasi-insulating' (dρ/dT 2 Ge 2 will be discussed. Of particular interest is the resistivity of as-grown URh 2 Ge 2 , which resembles the Non-Fermi-liquid system UCu 4 Pd, suggesting that a common mechanism - the crystallographic disorder - controls the transport properties of these materials

  10. Halo-lensing or Self-lensing? Locating the MACHO Lenses

    Science.gov (United States)

    Nelson, C. A.; Cook, K. H.; Popowski, P.; Drake, A. J.; Marshall, S. L.; Griest, K.; Vandehei, T.; Alcock, C.; Allsman, R. A.; Axelrod, T. S.; Freeman, K. C.; Peterson, B. A.; Alves, D. R.; Becker, A. C.; Stubbs, C. W.; Tomaney, A. B.; Bennett, D. P.; Geha, M.; Lehner, M. J.; Minniti, D.; Pratt, M. R.; Quinn, P. J.; Sutherland, W.; Welch, D.; MACHO Collaboration

    2000-12-01

    There are two principle geometrical arrangements which may explain Large Magellanic Cloud (LMC) microlensing: a) halo-lensing, in which the lensed object is part of the Milky Way galactic halo and b) self-lensing, in which the lensed object is part of the LMC. Self-lensing in turn may be broken into two categories: LMC-LMC self-lensing, in which both the source and the lens reside in the LMC and background self-lensing, in which the lens is a star in the LMC and the source star is drawn from some population behind the LMC. Models suggest the contribution of LMC-LMC self-lensing is small, so the nature of LMC microlensing may be estimated from the location of the microlensing source stars. If the source stars are in the LMC then microlensing is dominated by halo-lensing; conversely if the source stars are located behind the LMC then microlensing is dominated by self-lensing. Since background populations reside behind the LMC, we expect them to be both redder and fainter then the average population of the LMC. We attempt to determine if the MACHO source stars come from such a background population by comparing the HST color-magnitude diagram (CMD) of source stars to the CMD of the average population of the LMC and looking for the effects of extra reddening and extinction. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. Preliminary results suggest that halo-lensing accounts for ≳ 40% of the observed microlensing results. Support provided by NASA, DOE, NSF and NPSC.

  11. Semiclassical gravitational effects on the gravitational lensing in the spacetime of topological defects

    Science.gov (United States)

    Jusufi, Kimet; Rahaman, Farook; Banerjee, Ayan

    2018-02-01

    The theory of gravitational lensing has revealed many generic and fundamental properties of compact objects like black holes and wormholes. In this article, we utilize a recent formulation to compute the quantum effects on the deflection angle of a light ray, namely, the Gauss-Bonnet theorem (GBT) to explore the semiclassical gravitational effects in the spacetime of a point-like global monopole and a cosmic string. Previously, the Gauss-Bonnet theorem (Gibbons and Werner, 2008) was proposed as an alternative way to compute the deflection angle of light in a static, spherically symmetric and asymptotically flat spacetime. In the present article we have used the celebrated GBT that applied to the optical metric as well as the geodesic method in computing the deflection angle. Interestingly one can observe that we have found an exact result between GBT and the standard approach up to the third-order contributions terms by modifying the domain of integration for cosmic string and global monopole deflection angles. Finally we have considered the time delay in the cosmic string/global monopole spacetime and found that the delay in time is proportional to the linear mass density of the cosmic string and global monopole parameter, respectively.

  12. Drug release from liposome coated hydrogels for soft contact lenses: the blinking and temperature effect.

    Science.gov (United States)

    Paradiso, P; Colaço, R; Mata, J L G; Krastev, R; Saramago, B; Serro, A P

    2017-10-01

    In this article, liposome-based coatings aiming to control drug release from therapeutic soft contact lenses (SCLs) materials are analyzed. A PHEMA based hydrogel material loaded with levofloxacin is used as model system for this research. The coatings are formed by polyelectrolyte layers containing liposomes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and DMPC + cholesterol (DMPC + CHOL). The effect of friction and temperature on the drug release is investigated. The aim of the friction tests is to simulate the blinking of the eyelid in order to verify if the SCLs materials coated with liposomes are able to keep their properties, in particular the drug release ability. It was observed that under the study conditions, friction did not affect significantly the drug release from the liposome coated PHEMA material. In contrast, increasing the temperature of release leads to an increase of the drug diffusion rate through the hydrogel. This phenomenon is recorded both in the control and in the coated samples. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1799-1807, 2017. © 2016 Wiley Periodicals, Inc.

  13. Effect of plasma treatment on the performance of two drug-loaded hydrogel formulations for therapeutic contact lenses.

    Science.gov (United States)

    Paradiso, Patrizia; Chu, Virginia; Santos, Luís; Serro, Ana Paula; Colaço, Rogério; Saramago, Benilde

    2015-07-01

    Although the plasma technology has long been applied to treat contact lenses, the effect of this treatment on the performance of drug-loaded contact lenses is still unclear. The objective of this work is to study the effect of nitrogen plasma treatment on two drug-loaded polymeric formulations which previously demonstrated to be suitable for therapeutic contact lenses: a poly-hydroxyethylmethacrylate (pHEMA) based hydrogel loaded with levofloxacin and a silicone-based hydrogel loaded with chlorhexidine. Modifications of the surface and the optical properties, and alterations in the drug release profiles and possible losses of the antimicrobial activities of the drugs induced by the plasma treatment were assessed. The results showed that, depending on the system and on the processing conditions, the plasma treatment may be beneficial for increasing wettability and refractive index, without degrading the lens surface. From the point of view of drug delivery, plasma irradiation at moderate power (200 W) decreased the initial release rate and the amount of released drug, maintaining the drug activity. For lower (100 W) and higher powers (300 W), almost no effect was detected because the treatment was, respectively, too soft and too aggressive for the lens materials. © 2014 Wiley Periodicals, Inc.

  14. The Protective Effect of Brown-, Gray-, and Blue-Tinted Lenses against Blue LED Light-Induced Cell Death in A2E-Laden Human Retinal Pigment Epithelial Cells.

    Science.gov (United States)

    Park, Sang-Il; Jang, Young Pyo

    2017-01-01

    A2E-laden ARPE-19 cells were exposed to a blue light to induce cytotoxicity, in order to investigate the protective effects of various tinted ophthalmic lenses against photo-induced cytotoxicity in human retinal pigment epithelial (RPE) cells laden with A2E, known to be among the etiologies of age-related macular degeneration (AMD). Different-colored tinted lenses with varying levels of tint and different filtering characteristics, such as polarized, blue-cut, and photochromatic lenses, were placed over the cells, and the protective efficacies thereof were evaluated by lactate dehydrogenase assay. When tinted lenses were placed over ARPE-19 cells, there were different reductions in cytotoxicity according to the colors and tint levels. The level of protection afforded by brown-tinted lenses was 6.9, 36.1, and 49% with a tint level of 15, 50, and 80%, respectively. For gray-tinted lenses, the protective effect was 16.3, 35, and 43.4% for the corresponding degree of tint, respectively. In the case of blue-tinted lenses, a protective effect of 20% was observed with 80% tinted lenses, but 15 and 50% tinted lenses provided no significant protection. In addition, photochromic lenses showed a protective effect but blue-cut lenses and polarized lenses provided no significant protection. Tinted lenses significantly reduced cytotoxicity in RPE cells irradiated with blue light. The protection was more efficient in lenses with a brown or gray tint than in blue-tinted lenses. Tinted glasses may provide significant protection against potential blue-light-induced photochemical and photo-oxidative damage in RPE cells. © 2016 S. Karger AG, Basel.

  15. Prevention of the adverse photic effects of peripheral light-focusing using UV-blocking contact lenses.

    Science.gov (United States)

    Kwok, L Stephen; Kuznetsov, Valerian A; Ho, Arthur; Coroneo, Minas T

    2003-04-01

    Peripheral light-focusing (PLF) is an occult form of ultraviolet radiation (UVR) hazardous to the human eye. In PLF, obliquely incident light is refracted from the peripheral cornea to concentrated sites inside the anterior segment. In the current study, the directionality of this phenomenon for UVR and whether PLF is established in outdoor settings exposed to sunlight were investigated. The protection provided by a UV-blocking contact lens was also evaluated. UVA and UVB sensors were placed on the nasal limbus of an anatomically based model eye. The temporal limbus was exposed to a UV light source placed at various angles behind the frontal plane. PLF was quantified with the sensor output. The ensemble was mounted in the orbit of a mannequin head and exposed to sunlight in three insolation environments within the region of Sydney, Australia. PLF for UVA and UVB was determined with no eyewear or with sunglasses and commercially available soft contact lenses, with and without UV-blocking capability. The intensity of UVA peaked at approximately 120 degrees incidence, the level at which the UVB response was also at its maximum. The intensification of UVA was up to x18.3. The intensity of PLF for UVA and UVB was reduced by an order of magnitude by a UV-blocking contact lens, whereas a clear contact lenses had a much lesser effect. Only the UV-blocking contact lens achieved a significant effect on UVA and UVB irradiance in the urban, beach, and mountain locales (P UV-blocking soft contact lenses. Sunglasses may be unable to shield oblique rays, unless side protection is incorporated. Contact lenses can offer UVR protection against all angles of incidence, including the peak-response angle. They can also protect the eye in settings in which the wearing of sunglasses is not feasible or convenient.

  16. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models.

    Science.gov (United States)

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-11

    In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3 mm of pupil diameter and from 0 to out-of-focus blur were collected and graphed. MTF values, measured at 555 nm of monochromatic light under each spatial frequency, were significantly higher than the values measured at 470 to 650 nm of polychromatic light. The influences of chromatic aberration on MTF values decreased with the increase in IOL diopter when the spatial frequency was ≤12 c/d, while increased effects were observed when the spatial frequency was ≥15 c/d. The MTF values of each IOL eye model were significantly lower than the MTF values of the Liou-Brennan eye models when measured at 555 nm of monochromatic light and at 470 to 650 nm of polychromatic light. The MTF values were also found to be increased with the increase in IOL diopter. With higher diopters of IOLs, the central thickness increased accordingly, which could have created increased chromatic aberration and decreased the retinal image quality. To improve the postoperative visual quality, IOLs with lower chromatic aberration should be selected for patients with short axial lengths.

  17. CALCLENS: weak lensing simulations for large-area sky surveys and second-order effects in cosmic shear power spectra

    Science.gov (United States)

    Becker, Matthew R.

    2013-10-01

    I present a new algorithm, Curved-sky grAvitational Lensing for Cosmological Light conE simulatioNS (CALCLENS), for efficiently computing weak gravitational lensing shear signals from large N-body light cone simulations over a curved sky. This new algorithm properly accounts for the sky curvature and boundary conditions, is able to produce redshift-dependent shear signals including corrections to the Born approximation by using multiple-plane ray tracing and properly computes the lensed images of source galaxies in the light cone. The key feature of this algorithm is a new, computationally efficient Poisson solver for the sphere that combines spherical harmonic transform and multigrid methods. As a result, large areas of sky (˜10 000 square degrees) can be ray traced efficiently at high resolution using only a few hundred cores. Using this new algorithm and curved-sky calculations that only use a slower but more accurate spherical harmonic transform Poisson solver, I study the convergence, shear E-mode, shear B-mode and rotation mode power spectra. Employing full-sky E/B-mode decompositions, I confirm that the numerically computed shear B-mode and rotation mode power spectra are equal at high accuracy (≲1 per cent) as expected from perturbation theory up to second order. Coupled with realistic galaxy populations placed in large N-body light cone simulations, this new algorithm is ideally suited for the construction of synthetic weak lensing shear catalogues to be used to test for systematic effects in data analysis procedures for upcoming large-area sky surveys. The implementation presented in this work, written in C and employing widely available software libraries to maintain portability, is publicly available at http://code.google.com/p/calclens.

  18. LoCuSS: THE SUNYAEV–ZEL'DOVICH EFFECT AND WEAK-LENSING MASS SCALING RELATION

    International Nuclear Information System (INIS)

    Marrone, Daniel P.; Carlstrom, John E.; Gralla, Megan; Greer, Christopher H.; Hennessy, Ryan; Leitch, Erik M.; Plagge, Thomas; Smith, Graham P.; Okabe, Nobuhiro; Bonamente, Massimiliano; Hasler, Nicole; Culverhouse, Thomas L.; Hawkins, David; Lamb, James W.; Muchovej, Stephen; Joy, Marshall; Martino, Rossella; Mazzotta, Pasquale; Miller, Amber; Mroczkowski, Tony

    2012-01-01

    We present the first weak-lensing-based scaling relation between galaxy cluster mass, M WL , and integrated Compton parameter Y sph . Observations of 18 galaxy clusters at z ≅ 0.2 were obtained with the Subaru 8.2 m telescope and the Sunyaev-Zel'dovich Array. The M WL -Y sph scaling relations, measured at Δ = 500, 1000, and 2500 ρ c , are consistent in slope and normalization with previous results derived under the assumption of hydrostatic equilibrium (HSE). We find an intrinsic scatter in M WL at fixed Y sph of 20%, larger than both previous measurements of M HSE -Y sph scatter as well as the scatter in true mass at fixed Y sph found in simulations. Moreover, the scatter in our lensing-based scaling relations is morphology dependent, with 30%-40% larger M WL for undisturbed compared to disturbed clusters at the same Y sph at r 500 . Further examination suggests that the segregation may be explained by the inability of our spherical lens models to faithfully describe the three-dimensional structure of the clusters, in particular, the structure along the line of sight. We find that the ellipticity of the brightest cluster galaxy, a proxy for halo orientation, correlates well with the offset in mass from the mean scaling relation, which supports this picture. This provides empirical evidence that line-of-sight projection effects are an important systematic uncertainty in lensing-based scaling relations.

  19. The wearing of hydrophilic contact lenses aboard a commercial jet aircraft: I. Humidity effects on fit.

    Science.gov (United States)

    Eng, W G; Harada, L K; Jagerman, L S

    1982-03-01

    The increasing use of hydrophilic (soft) lenses in the United States hs prompted interest in the clinical investigation of these lenses under various wearing conditions. Any factor causing lens dehydration during wear may affect lens performance and ultimately cause eye discomfort. The purpose of this study was to evaluate the environmental conditions in the aircraft cabin and to observe any changes in the fit of the hydrophilic lenses that might occur during flight. A "laboratory" for testing was set up aboard a World Airways DC-10 on a scheduled round trip between Oakland, California and Honolulu, Hawaii. A keratometer was used to assess lens fit of seven subjects who were wearing hydrophilic lenses. The efficacy of using a soft lens hydrating solution on the fit of the lens was evaluated, but will also be evaluated in a future paper. Atmospheric pressure, humidity, and temperature measurements were recorded throughout the inflight study. The results showed that a decline in cabin humidity from at least 47% to 11% occurred within 30 min of takeoff. Although previous reports have indicated that there are a number of environmental factors in the aircraft that contribute to eye discomfort for lens wearers, this study indicates that low cabin humidity is possibly the most significant factor.

  20. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Collett, T. E.; Furlanetto, C.; Gill, M. S. S.; More, A.; Nightingale, J.; Odden, C.; Pellico, A.; Tucker, D. L.; Costa, L. N. da; Neto, A. Fausti; Kuropatkin, N.; Soares-Santos, M.; Welch, B.; Zhang, Y.; Frieman, J. A.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; Desai, S.; Dietrich, J. P.; Drlica-Wagner, A.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; García-Bellido, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; James, D. J.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Menanteau, F.; Miquel, R.; Nichol, R. C.; Nugent, P.; Ogando, R. L. C.; Plazas, A. A.; Reil, K.; Romer, A. K.; Sako, M.; Sanchez, E.; Santiago, B.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2017-09-01

    We report the results of our searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verication and Year 1 observations. The Science Verication data spans approximately 250 sq. deg. with median i

  1. A Comparison Of X-ray, Radio, And Lensing Results With GBT+MUSTANG Observations Of The Sunyaev-Zel'dovich Effect In Galaxy Clusters

    Science.gov (United States)

    Mroczkowski, Tony; Devlin, M.; Dicker, S.; Korngut, P.; Mason, B.; Reese, E.; Romero, C.; Sarazin, C.; Sun, M.; Young, A.; Lensing, Cluster; survey with Hubble, Supernova

    2012-05-01

    We present recent high angular resolution (9") Sunyaev-Zel'dovich effect (SZE) observations with MUSTANG, a 90-GHz bolometric receiver on the 100-meter Green Bank Telescope (GBT). MUSTANG is now imaging a sample of clusters with complementary Chandra X-ray observations, HST optical observations that probe the mass distribution through strong and weak lensing, radio observations that probe the non-thermal component of the intra-cluster gas, and lower resolution SZE observations that can recover larger scales (>1'). The MUSTANG observations, which will be used to assess the impact of substructure on SZE scaling relations, are some of the highest resolution SZE images to date, and are revealing complex pressure substructures in intermediate redshift clusters. Combined, these observations reveal complicated cluster dynamics, which must be understood in order to use clusters as cosmological probes.

  2. OBSERVATION OF STRONG - STRONG AND OTHER BEAM - BEAM EFFECTS IN RHIC

    International Nuclear Information System (INIS)

    FISCHER, W.; BLASKIEWICZ, M.; BRENNAN, J.M.; CAMERON, P.; CONNOLLY, R.; MONTAG, C.; PEGGS, S.; PILAT, F.; PTITSYN, V.; TEPIKIAN, S.; TRBOJEVIC, D.; VAN ZEIJTS, J.

    2003-01-01

    RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. For the first time, coherent beam-beam modes were observed in a bunched beam hadron collider. Other beam-beam effects in RHIC were observed in operation and in dedicated experiments with gold ions, deuterons and protons. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. During ramps unequal radio frequencies in the two rings cause the crossing points to move longitudinally. Thus bunches experience beam-beam interactions only in intervals and the tunes are modulated. In this article we summarize the most important beam-beam observations made so far

  3. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Odden, C.; Pellico, A.; Tucker, D. L.; Kuropatkin, N.; Soares-Santos, M. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Collett, T. E. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Furlanetto, C.; Nightingale, J. [University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD (United Kingdom); Gill, M. S. S. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); More, A. [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Costa, L. N. da; Neto, A. Fausti, E-mail: diehl@fnal.gov [Laboratório Interinstitucional de e-Astronomia—LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400 (Brazil); Collaboration: DES Collaboration; and others

    2017-09-01

    We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median i -band limiting magnitude for extended objects (10 σ ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an i -band limiting magnitude for extended objects (10 σ ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified based on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.

  4. The kinematical structure of gravitationally lensed arcs

    NARCIS (Netherlands)

    Moller, O; Noordermeer, E

    2006-01-01

    In this paper, the expected properties of the velocity fields of strongly lensed arcs behind galaxy clusters are investigated. The velocity profile along typical lensed arcs is determined by ray-tracing light rays from a model source galaxy through parametric cluster toy models consisting of

  5. Effect of patient wear and extent of protein deposition on adsorption of Acanthamoeba to five types of hydrogel contact lenses.

    Science.gov (United States)

    Simmons, P A; Tomlinson, A; Connor, R; Hay, J; Seal, D V

    1996-06-01

    Attachment of Acanthamoeba species to hydrogel contact lenses is a possible route of infection in Acanthamoeba keratitis. In this study, Acanthamoeba adsorption was compared with extent of lens deposition in worn lenses of different hydrogel polymers. After wear, lenses (80 lenses of 5 different types) were analyzed for total protein, surface area of deposition, and Acanthamoeba castellani trophozoite and cyst adsorption. Adsorption of Acanthamoeba trophozoites to worn lenses was greater than adsorption to unworn lenses for four of the five lens polymers (p 0.05). Adsorption was affected by both the water content and ionicity of the lens polymer. These results show that adsorption of Acanthamoeba to worn hydrogel contact lenses is greater than or equal to adsorption to unworn lenses.

  6. [The effect of gamma rays on glutathion and ascorbic acid content in rabbit lenses (author's transl)].

    Science.gov (United States)

    Zygulska-Mach, H; Mach, Z

    1975-01-01

    It is pointed out that the partner non radiated eye is also influenced after employment of high radiation on an eye. The authors radiated rabbit eyes with gamma rays employing Stallard-applicators and determined the glutathion and ascorbic acid content in the lenses. The lenses of the partner eye were also examined for comparison. In those eyes which were directly radiated there was a fall of concentration of the two substances indirectly proportional to the dose of rays employed. In the partner eyes which were not directly subjected to direct radiation there were changes of similar character which were however not so much pronounced. The role of glutathion and ascorbic acid in lens metabolism is pointed out.

  7. The effects of daily wear contact lenses on goblet cell density.

    Science.gov (United States)

    Connor, C G; Campbell, J B; Steel, S A; Burke, J H

    1994-11-01

    Some patients can wear contact lenses with a low tear breakup time while others with an identical tear breakup time cannot wear lenses. This suggests the current method of tear film assessment is inadequate at differentiating between these two types of patients. The study attempts to expand our knowledge of the tear film with special attention directed to a critical yet little studied component: mucin. Mucin is vital to maintenance of the tear film and functions as a tear film stabilizer. The condition of the precorneal tear film is a major determinant in the success of contact lens wear. Eighteen subjects free of ocular surface disease who had never worn contact lenses had the goblet cell density of their inferior bulbar conjunctiva determined by impression cytology. The subjects were then fit in a 38 percent water polymacon lens and their goblet cell density determined on a monthly basis for 6 months. Nearly a 2-fold increase in goblet cell density was observed in 88 percent of the subjects over the 6-month period. The first statistically significant increase occurred 5 months after the initiation of lens wear when the goblet cell density rose from 4.19-7.84 percent. We speculate the increase in goblet cells is an adaptive response of the ocular surface to a coated daily wear contact lens.

  8. SPITZER ULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 ≲ z ≲ 10 BEHIND STRONG-LENSING CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuang-Han; Bradač, Maruša; Hoag, Austin; Cain, Benjamin; Lubin, L. M.; Knight, Robert I. [University of California Davis, 1 Shields Avenue, Davis, CA 95616 (United States); Lemaux, Brian C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ryan, R. E. Jr.; Brammer, Gabriel B. [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Castellano, Marco; Amorin, Ricardo; Fontana, Adriano; Merlin, Emiliano [INAF—Osservatorio Astronomico di Roma Via Frascati 33, I-00040 Monte Porzio Catone (Italy); Schmidt, Kasper B. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Schrabback, Tim [Argelander-Institut für Astronomie, Auf Dem Hügel 71, D-53121 Bonn (Germany); Treu, Tommaso [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Linden, Anja von der, E-mail: khhuang@ucdavis.edu, E-mail: astrokuang@gmail.com [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305 (United States)

    2016-01-20

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios  ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ∼1.2–5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M{sub 1600} are between −21.2 and −18.9 mag, while their intrinsic stellar masses are between 2 × 10{sup 8}M{sub ⊙} and 2.9 × 10{sup 9}M{sub ⊙}. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at z{sub Lyα} = 6.76 (in RXJ 1347) and one at z{sub Lyα} = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]–[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  9. Characteristics of a laser beam produced by using thermal lensing effect compensation in a fiber-coupled laser-diode-pumped Nd:YAG ceramic laser

    International Nuclear Information System (INIS)

    Kim, Duck-Lae; Kim, Byung-Tai

    2010-01-01

    The characteristics of a laser beam produced by using thermal lensing effect compensation in a fiber-coupled laser-diode Nd:YAG ceramic laser were investigated. The thermal lensing effect was compensated for by using a compensator, which was 25 mm away from the laser rod, with a focal length of 30 mm and an effective clear aperture of 22 mm. Using a compensator, the divergence and the beam propagation factor M 2 of the output beam were 5.5 mrad and 2.4, respectively, under a pump power of 12W. The high-frequency components in the compensated laser beam were removed.

  10. The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle: a systematic review of the literature.

    Science.gov (United States)

    Lawrenson, John G; Hull, Christopher C; Downie, Laura E

    2017-11-01

    Blue-blocking (BB) spectacle lenses, which attenuate short-wavelength light, are being marketed to alleviate eyestrain and discomfort when using digital devices, improve sleep quality and potentially confer protection from retinal phototoxicity. The aim of this review was to investigate the relative benefits and potential harms of these lenses. We included randomised controlled trials (RCTs), recruiting adults from the general population, which investigated the effect of BB spectacle lenses on visual performance, symptoms of eyestrain or eye fatigue, changes to macular integrity and subjective sleep quality. We searched MEDLINE, EMBASE, the Cochrane Library and clinical trial registers, until 30 April 2017. Risk of bias was assessed using the Cochrane tool. Three studies (with 136 participants) met our inclusion criteria; these had limitations in study design and/or implementation. One study compared the effect of BB lenses with clear lenses on contrast sensitivity (CS) and colour vision (CV) using a pseudo-RCT crossover design; there was no observed difference between lens types (log CS; Mean Difference (MD) = -0.01 [-0.03, 0.01], CV total error score on 100-hue; MD = 1.30 [-7.84, 10.44]). Another study measured critical fusion frequency (CFF), as a proxy for eye fatigue, on wearers of low and high BB lenses, pre- and post- a two-hour computer task. There was no observed difference between low BB and standard lens groups, but there was a less negative change in CFF between the high and low BB groups (MD = 1.81 [0.57, 3.05]). Both studies compared eyestrain symptoms with Likert scales. There was no evidence of inter-group differences for either low BB (MD = 0.00 [-0.22, 0.22]) or high BB lenses (MD = -0.05 [-0.31, 0.21]), nor evidence of a difference in the proportion of participants showing an improvement in symptoms of eyestrain or eye fatigue. One study reported a small improvement in sleep quality in people with self-reported insomnia after wearing

  11. Cosmology with weak lensing surveys

    International Nuclear Information System (INIS)

    Munshi, Dipak; Valageas, Patrick; Waerbeke, Ludovic van; Heavens, Alan

    2008-01-01

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also

  12. The BOSS Emission-line Lens Survey. V. Morphology and Substructure of Lensed Lyα Emitters at Redshift Z ≈ 2.5 in the BELLS GALLERY

    Science.gov (United States)

    Cornachione, Matthew A.; Bolton, Adam S.; Shu, Yiping; Zheng, Zheng; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Oguri, Masamune; Kochanek, Christopher S.; Mao, Shude; Pèrez-Fournon, Ismael; Marques-Chaves, Rui; Mènard, Brice

    2018-02-01

    We present a morphological study of the 17 lensed Lyα emitter (LAE) galaxies of the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Lyα EmitteR sYstems (BELLS GALLERY) sample. This analysis combines the magnification effect of strong galaxy–galaxy lensing with the high resolution of the Hubble Space Telescope to achieve a physical resolution of ∼80 pc for this 2 matter substructure in the foreground lensing galaxies.

  13. LoCuSS: A COMPARISON OF SUNYAEV-ZEL'DOVICH EFFECT AND GRAVITATIONAL-LENSING MEASUREMENTS OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Marrone, Daniel P.; Culverhouse, Thomas; Carlstrom, John E.; Greer, Christopher; Hennessy, Ryan; Leitch, Erik M.; Loh, Michael; Pryke, Clem; Smith, Graham P.; Hamilton-Morris, Victoria; Richard, Johan; Joy, Marshall; Bonamente, Massimiliano; Hasler, Nicole; Kneib, Jean-Paul; Hawkins, David; Lamb, James W.; Muchovej, Stephen; Miller, Amber; Mroczkowski, Tony

    2009-01-01

    We present the first measurement of the relationship between the Sunyaev-Zel'dovich effect (SZE) signal and the mass of galaxy clusters that uses gravitational lensing to measure cluster mass, based on 14 X-ray luminous clusters at z ≅ 0.2 from the Local Cluster Substructure Survey. We measure the integrated Compton y-parameter, Y, and total projected mass of the clusters (M GL ) within a projected clustercentric radius of 350 kpc, corresponding to mean overdensities of 4000-8000 relative to the critical density. We find self-similar scaling between M GL and Y, with a scatter in mass at fixed Y of 32%. This scatter exceeds that predicted from numerical cluster simulations, however, it is smaller than comparable measurements of the scatter in mass at fixed T X . We also find no evidence of segregation in Y between disturbed and undisturbed clusters, as had been seen with T X on the same physical scales. We compare our scaling relation to the Bonamente et al. relation based on mass measurements that assume hydrostatic equilibrium, finding no evidence for a hydrostatic mass bias in cluster cores (M GL = 0.98 ± 0.13 M HSE ), consistent with both predictions from numerical simulations and lensing/X-ray-based measurements of mass-observable scaling relations at larger radii. Overall our results suggest that the SZE may be less sensitive than X-ray observations to the details of cluster physics in cluster cores.

  14. Investigating cluster astrophysics and cosmology with cross-correlation of the thermal Sunyaev-Zel'dovich effect and weak lensing

    Science.gov (United States)

    Osato, Ken; Flender, Samuel; Nagai, Daisuke; Shirasaki, Masato; Yoshida, Naoki

    2018-03-01

    Recent detections of the cross-correlation of the thermal Sunyaev-Zel'dovich (tSZ) effect and weak gravitational lensing (WL) enable unique studies of cluster astrophysics and cosmology. In this work, we present constraints on the amplitude of the non-thermal pressure fraction in galaxy clusters, α0, and the amplitude of the matter power spectrum, σ8, using measurements of the tSZ power spectrum from Planck, and the tSZ-WL cross-correlation from Planck and the Red Cluster Sequence Lensing Survey. We fit the data to a semi-analytic model with the covariance matrix using N-body simulations. We find that the tSZ power spectrum alone prefers σ8 ˜ 0.85 and a large fraction of non-thermal pressure (α0 ˜ 0.2-0.3). The tSZ-WL cross-correlation on the other hand prefers a significantly lower σ8 ˜ 0.6 and low α0 ˜ 0.05. We show that this tension can be mitigated by allowing for a steep slope in the stellar mass-halo mass relation, which would cause a reduction of the gas in low-mass haloes. In such a model, the combined data prefer σ8 ˜ 0.7 and α0 ˜ 0.2, consistent with predictions from hydrodynamical simulations.

  15. Relative radiosensitivity of rat lenses as a function of age

    International Nuclear Information System (INIS)

    Merriam, G.R. Jr.; Szechter, A.

    1975-01-01

    The effect of age on the development of radiation cataracts in rat lenses has been investigated using the Columbia--Sherman rat as an experiment model. A detailed pattern of age dependence was obtained at several different dose levels. In general at dose levels from 200 to 300 rads the lens changes occurred sooner and progressed faster in the adult lenses than in young lenses. In the dose range from 300 rads to 900 rads opacities developed sooner in the young lenses but progression was faster and severe opacities developed sooner in adult lenses. Above 900 rads opacities developed sooner and progressed faster in the young lenses. (U.S.)

  16. Strong expectations cancel locality effects: evidence from Hindi.

    Directory of Open Access Journals (Sweden)

    Samar Husain

    Full Text Available Expectation-driven facilitation (Hale, 2001; Levy, 2008 and locality-driven retrieval difficulty (Gibson, 1998, 2000; Lewis & Vasishth, 2005 are widely recognized to be two critical factors in incremental sentence processing; there is accumulating evidence that both can influence processing difficulty. However, it is unclear whether and how expectations and memory interact. We first confirm a key prediction of the expectation account: a Hindi self-paced reading study shows that when an expectation for an upcoming part of speech is dashed, building a rarer structure consumes more processing time than building a less rare structure. This is a strong validation of the expectation-based account. In a second study, we show that when expectation is strong, i.e., when a particular verb is predicted, strong facilitation effects are seen when the appearance of the verb is delayed; however, when expectation is weak, i.e., when only the part of speech "verb" is predicted but a particular verb is not predicted, the facilitation disappears and a tendency towards a locality effect is seen. The interaction seen between expectation strength and distance shows that strong expectations cancel locality effects, and that weak expectations allow locality effects to emerge.

  17. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  18. The effect of tinted spectacle lenses on contrast sensitivity and colour vision

    Directory of Open Access Journals (Sweden)

    M. Shaik

    2013-12-01

    The greater enhancement was for low spatial frequencies (LSF and least for high spatial frequencies (HSF. With all tints Grade C had the least enhancement for very HSF. Many subjects showed no change in CV with any of the lensesused. The grey tint showed greater enhancement of CV as the density increases. Blue and brown tints showed a similar trend with grade B enhancing CV the most while grade C resulted in theleast reduction of CV. Conclusion: Grade A, B, and C of blue, brown and grey tinted spectacle lenses do not alter colour vision significantly but for the selected levels of transmission of the tints used, contrast sensitivity can be improved to some extent.

  19. Investigations of Galaxy Clusters Using Gravitational Lensing

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Matthew P. [Northern Illinois Univ., DeKalb, IL (United States)

    2014-08-01

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  20. RHIC electron lenses upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Altinbas, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Binello, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Costanzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, J. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mi, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Pikin, A. I. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Samms, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Shrey, T. C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Tan, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  1. Soft Lenses | Kuming | South African Medical Journal

    African Journals Online (AJOL)

    A series of cases fitted with Bionite soft lenses is described. Good results were obtained in bullous keratopathy, dry eyes, early and moderately advanced Stevens-Johnson syndrome and pemphigoid, and some cases of indolent corneal ulcers. The lenses appear to be a most effective replacement for tarsorrhaphy, haptic ...

  2. The effect of blue-blocking and neutral intraocular lenses on circadian photoentrainment and sleep one year after cataract surgery

    DEFF Research Database (Denmark)

    Brøndsted, Adam Elias; Haargaard, Birgitte; Sander, Birgit

    2017-01-01

    PURPOSE: To compare the long-term effect on circadian photoentrainment and sleep in patients implanted with neutral and blue-blocking intraocular lenses 1 year after cataract surgery. METHODS: Randomized, controlled trial involving 67 patients with age-related cataract. Intervention was cataract......; the latter was also used to determine objective sleep quality. The Pittsburgh Sleep Quality Index determined subjective sleep quality. RESULTS: One year after surgery, peak melatonin concentration was 3.3 pg/ml (95% CI, 2-5.5) corresponding to 50% lower for the participants allocated to blue-blocking IOLs...... compared with participants allocated to neutral IOLs. Compared with preoperative levels, the ipRGC response had increased by 13.7% (95% confidence interval [CI], 3.2-22.6) 1 year after surgery. Objective sleep quality was also improved as the time of wakefulness after sleep onset had improved by 5 min (95...

  3. Strong Gravity Effects of Rotating Black Holes: Quasiperiodic Oscillations

    OpenAIRE

    Aliev, Alikram N.; Esmer, Göksel Daylan; Talazan, Pamir

    2012-01-01

    We explore strong gravity effects of the geodesic motion in the spacetime of rotating black holes in general relativity and braneworld gravity. We focus on the description of the motion in terms of three fundamental frequencies: The orbital frequency, the radial and vertical epicyclic frequencies. For a Kerr black hole, we perform a detailed numerical analysis of these frequencies at the innermost stable circular orbits and beyond them as well as at the characteristic stable orbits, at which ...

  4. New results on strong-interaction effects in antiprotonic hydrogen

    CERN Document Server

    Gotta, D; Augsburger, M A; Borchert, G L; Castelli, C M; Chatellard, D; El-Khoury, P; Egger, J P; Gorke, H; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Nelms, N; Rashid, K; Schult, O W B; Siems, T; Simons, L M

    1999-01-01

    Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the low-energy antiproton ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using charge-coupled devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction. (33 refs).

  5. New results on strong-interaction effects in antiprotonic hydrogen

    International Nuclear Information System (INIS)

    Anagnostopoulos, D. F.; Augsburger, M.; Borchert, G.; Castelli, C.; Chatellard, D.; El-Khoury, P.; Egger, J.-P.; Gorke, H.; Gotta, D.; Hauser, P.; Indelicato, P.; Kirch, K.; Lenz, S.; Nelms, N.; Rashid, K.; Schult, O. W. B.; Siems, Th.; Simons, L. M.

    1999-01-01

    Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the Low-Energy Antiproton Ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using Charge-Coupled Devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction

  6. Will the recently approved LARES mission be able to measure the Lense-Thirring effect at 1%?

    Science.gov (United States)

    Iorio, Lorenzo

    2009-08-01

    After the approval by the Italian Space Agency of the LARES satellite, which should be launched at the end of 2009 with a VEGA rocket and whose claimed goal is a ≈1% measurement of the general relativistic gravitomagnetic Lense-Thirring effect in the gravitational field of the Earth, it is of the utmost importance to reliably assess the total realistic accuracy that can be reached by such a mission. The observable is a linear combination of the nodes of the existing LAGEOS and LAGEOS II satellites and of LARES able to cancel out the impact of the first two even zonal harmonic coefficients of the multipolar expansion of the classical part of the terrestrial gravitational potential representing a major source of systematic error. While LAGEOS and LAGEOS II fly at altitudes of about 6,000 km, LARES should be placed at an altitude of 1,450 km. Thus, it will be sensitive to much more even zonals than LAGEOS and LAGEOS II. Their corrupting impact has been evaluated up to degree ℓ = 70 by using the sigmas of the covariance matrices of eight different global gravity solutions (EIGEN-GRACE02S, EIGEN-CG03C, GGM02S, GGM03S, JEM01-RL03B, ITG-Grace02s, ITG-Grace03, EGM2008) obtained by five institutions (GFZ, CSR, JPL, IGG, NGA) with different techniques from long data sets of the dedicated GRACE missions. It turns out to be ≈100-1,000% of the Lense-Thirring effect. An improvement of 2-3 orders of magnitude in the determination of the high degree even zonals would be required to constrain the bias to ≈1-10%.

  7. Colored lenses suppress blue light-emitting diode light-induced damage in photoreceptor-derived cells.

    Science.gov (United States)

    Hiromoto, Kaho; Kuse, Yoshiki; Tsuruma, Kazuhiro; Tadokoro, Nobuyuki; Kaneko, Nobuyuki; Shimazawa, Masamitsu; Hara, Hideaki

    2016-03-01

    Blue light-emitting diodes (LEDs) in liquid crystal displays emit high levels of blue light, exposure to which is harmful to the retina. Here, we investigated the protective effects of colored lenses in blue LED light-induced damage to 661W photoreceptor-derived cells. We used eight kinds of colored lenses and one lens that reflects blue light. Moreover, we evaluated the relationship between the protective effects of the lens and the transmittance of lens at 464 nm. Lenses of six colors, except for the SY, PN, and reflective coating lenses, strongly decreased the reduction in cell damage induced by blue LED light exposure. The deep yellow lens showed the most protective effect from all the lenses, but the reflective coating lens and pink lens did not show any effects on photoreceptor-derived cell damage. Moreover, these results were correlated with the lens transmittance of blue LED light (464 nm). These results suggest that lenses of various colors, especially deep yellow lenses, may protect retinal photoreceptor cells from blue LED light in proportion to the transmittance for the wavelength of blue LED and the suppression of reactive oxygen species production and cell damage.

  8. Use of Scleral Lenses and Miniscleral Lenses After Penetrating Keratoplasty.

    Science.gov (United States)

    Barnett, Melissa; Lien, Vivian; Li, Jennifer Y; Durbin-Johnson, Blythe; Mannis, Mark J

    2016-05-01

    To examine the clinical outcomes of scleral lenses for visual rehabilitation after penetrating keratoplasty (PK). A retrospective review was conducted for 34 patients (48 eyes) who had a history of prior PK and were fit with scleral lenses between October 2009 and December 2013 at the UC Davis Eye Center. The most common initial indication for PK was keratoconus in 27 eyes (56%). Thirty-three eyes (69%) had previously been fit with other types of contact lenses, with small-diameter rigid gas-permeable lenses being the most common. The improvement in best-corrected visual acuity with a scleral lens compared with prior spectacle refraction or other contact lens was a mean of two best-corrected visual acuity lines. Forty-four eyes (91.7%) achieved functional vision with best scleral lens-corrected visual acuities of 20/40 or better. Patients who continued wearing scleral lenses were significantly more likely to report "good" subjective vision compared with patients who abandoned scleral lens wear (P=0.009), although change in objective best-corrected visual acuity did not differ significantly. There were no cases of infectious keratitis. Six eyes (12.5%) developed graft rejection; 3 were able to resume scleral lens wear. Nineteen eyes (39.5%) discontinued scleral lens wear for various reasons, the most common reason for discontinuation of lens wear was difficulty with scleral lens insertion or removal (8 eyes, 42.1%). Scleral lenses are effective and safe in patients who have had PK. There was a mean gain in visual acuity, with the majority of patients achieving 20/40 vision or better. The patient's subjective perception of vision was a significant factor in determining whether scleral lens wear was continued or abandoned.

  9. An Experimental Study on the Effect of Using Fresnel Lenses on the Performance of Solar Stills

    Science.gov (United States)

    Abdelsalam, Tarek I.; Abdel-Mesih, Bahy

    The global water concern is mainly about the scarcity of fresh water resources despite the abundance of saline and brackish water in oceans, seas, and underground. Solar desalination offers a worthy solution to produce fresh water by using solar radiation, which also lessens the energy concern by offering a renewable source of energy to alter the consumption of fossil fuels and other non-renewable resources. One of the solar desalination technologies is the solar still system, which is a portable unit capable of producing distilled water by evaporating brackish or saline water by using solar thermal energy. The steam is then condensed on the inside of the glass cover and collected as fresh water. Solar stills are easy to manufacture and install using local materials and workmanship, which suits underprivileged remote communities that face difficulties in finding clean potable water, while locating near a source of saline water. However, efficiency and productivity of solar stills are still feeble when compared to other traditional desalination techniques. As an attempt to overcome these issues, an upgraded system is proposed and tested experimentally to augment the incoming solar radiation falling on the top glass surface of the still by concentrating extra solar radiation to preheat the flowing feedwater to the solar still system. The results of the experimental study showed that the integration of linear Fresnel lenses has approximately tripled the productivity of distilled water and improved efficiency of a solar still, by about 68.76 %, when compared to a conventional non-concentrating solar still.

  10. The effect of surface treatment of silicone hydrogel contact lenses on the attachment of Acanthamoeba castellanii trophozoites.

    Science.gov (United States)

    Beattie, Tara K; Tomlinson, Alan

    2009-11-01

    To determine if plasma surface treatment of Focus Night & Day silicone hydrogel contact lenses affects the attachment of Acanthamoeba. Unworn lotrafilcon A contact lenses with (Focus Night & Day) and without surface treatment and Acuvue, conventional hydrogel lenses, were quartered before 90-min incubation with Acanthamoeba castellanii trophozoites. After incubation and rinsing, the trophozoites attached to one surface of each quarter were counted by direct light microscopy. Sixteen replicates were observed for each lens type. Logarithmic transformation of data allowed the use of parametric analysis of variance. No significant difference in attachment was established between the untreated lotrafilcon A and the conventional hydrogel lenses (Ptreatment of the native Focus Night & Day material produced a significant increase in attachment (Ptreatment to reduce lens hydrophobicity; however, this procedure results in an enhanced acanthamoebal attachment. It is possible that the silicone hydrogel lens could be at a greater risk of promoting Acanthamoeba infection if exposed to the organism because of the enhanced attachment characteristic of this material. Eye care professionals should be aware of the enhanced affinity that Acanthamoeba show for this lens and accordingly emphasise to patients the significance of appropriate lens hygiene. This is particularly important where lenses are worn in a regime that could increase the chance of exposure to the organism, i.e., 6 nights/7 days extended wear or daily wear, where lenses will be stored in a lens case, or where lenses are worn when in contact with potentially contaminated water sources, i.e., swimming or showering.

  11. Gravitational lensing of gravitational waves: A statistical perspective

    Science.gov (United States)

    Li, Shun-Sheng; Mao, Shude; Zhao, Yuetong; Lu, Youjun

    2018-02-01

    In this paper we study the strong gravitational lensing of gravitational waves (GWs) from a statistical perspective, with particular focus on the high frequency GWs from stellar binary black hole coalescences. These are most promising targets for ground-based detectors such as aLIGO and the proposed Einstein Telescope (ET) and can be safely treated under the geometrical optics limit for GW propagation. We perform a thorough calculation of the lensing rate, by taking account of effects caused by the ellipticity of lensing galaxies, lens environments, and magnification bias. We find that in certain GW source rate scenarios, we should be able to observe strongly lensed GW events once per year (˜1 yr-1) in the aLIGO survey at its design sensitivity; for the proposed ET survey, the rate could be as high as ˜80 yr-1. These results depend on the estimate of GW source abundance, and hence can be correspondingly modified with an improvement in our understanding of the merger rate of stellar binary black holes. We also compute the fraction of four-image lens systems in each survey, predicting it to be ˜30 percent for the aLIGO survey and ˜6 percent for the ET survey. Finally, we evaluate the possibility of missing some images due to the finite survey duration, by presenting the probability distribution of lensing time delays. We predict that this selection bias will be insignificant in future GW surveys, as most of the lens systems (˜90%) will have time delays less than ˜1 month which will be far shorter than survey durations.

  12. Gravitational lensing of gravitational waves: a statistical perspective

    Science.gov (United States)

    Li, Shun-Sheng; Mao, Shude; Zhao, Yuetong; Lu, Youjun

    2018-05-01

    In this paper, we study the strong gravitational lensing of gravitational waves (GWs) from a statistical perspective, with particular focus on the high frequency GWs from stellar binary black hole coalescences. These are most promising targets for ground-based detectors such as Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO) and the proposed Einstein Telescope (ET) and can be safely treated under the geometrical optics limit for GW propagation. We perform a thorough calculation of the lensing rate, by taking account of effects caused by the ellipticity of lensing galaxies, lens environments, and magnification bias. We find that in certain GW source rate scenarios, we should be able to observe strongly lensed GW events once per year (˜1 yr-1) in the aLIGO survey at its design sensitivity; for the proposed ET survey, the rate could be as high as ˜80 yr-1. These results depend on the estimate of GW source abundance, and hence can be correspondingly modified with an improvement in our understanding of the merger rate of stellar binary black holes. We also compute the fraction of four-image lens systems in each survey, predicting it to be ˜30 per cent for the aLIGO survey and ˜6 per cent for the ET survey. Finally, we evaluate the possibility of missing some images due to the finite survey duration, by presenting the probability distribution of lensing time delays. We predict that this selection bias will be insignificant in future GW surveys, as most of the lens systems ({˜ } 90{per cent}) will have time delays less than ˜1 month, which will be far shorter than survey durations.

  13. Arcs from gravitational lensing

    Science.gov (United States)

    Grossman, Scott A.; Narayan, Ramesh

    1988-01-01

    The proposal made by Paczynski (1987) that the arcs of blue light found recently in two cluster cores are gravitationally lensed elongated images of background galaxies is investigated. It is shown that lenses that are circularly symmetric in projection produce pairs of arcs, in conflict with the observations. However, more realistic asymmetric lenses produce single arcs, which can become as elongated as the observed ones whenever the background galaxy is located on or close to a cusp caustic. Detailed computer simulations of lensing by clusters using a reasonable model of the mass distribution are presented. Elongated and curved lensed images longer than 10 arcsec occur in 12 percent of the simulated clusters. It is concluded that the lensing hypothesis must be taken seriously.

  14. Superconducting proximity effect in the strong-coupling limit

    International Nuclear Information System (INIS)

    Wilvert, W.

    1975-01-01

    A generalization of the theory of the superconducting proximity effect is presented which takes into account strong-coupling in the superconductors. The results are found to agree with a model of weak-coupled superconductors with differing Debye frequencies which are in proximity. It is found that logarithmic averaging of phonon frequencies is an improvement on the original McMillan theory (1968). Comparison of the theory with data on thin films and on eutectic alloys is found to give good agreement. 19 references

  15. Strong dynamical effects during stick-slip adhesive peeling.

    Science.gov (United States)

    Dalbe, Marie-Julie; Santucci, Stéphane; Cortet, Pierre-Philippe; Vanel, Loïc

    2014-01-07

    We consider the classical problem of the stick-slip dynamics observed when peeling a roller adhesive tape at a constant velocity. From fast imaging recordings, we extract the dependence of the stick and slip phase durations on the imposed peeling velocity and peeled ribbon length. Predictions of Maugis and Barquins [in Adhesion 12, edited by K. W. Allen, Elsevier ASP, London, 1988, pp. 205-222] based on a quasistatic assumption succeed to describe quantitatively our measurements of the stick phase duration. Such a model however fails to predict the full stick-slip cycle duration, revealing strong dynamical effects during the slip phase.

  16. UV-vis light transmittance through tinted contact lenses and the effect of color on values.

    Science.gov (United States)

    Osuagwu, Uchechukwu L; Ogbuehi, Kelechi C

    2014-06-01

    To assess the transmittance, in the 200-700nm electromagnetic radiation spectrum, by popularly used tinted soft contact lenses (CLs). The spectra transmittances of ultraviolet (UV)-blocking (I Day Acuvue Define, Freshlook ONE DAY) and non-UV-blocking (Durasoft 3, Tutti, and NeoCosmo) tinted soft CLs were tested. The transmittance of each lens, including nine different colors of Freshlook CL was recorded on spectrophotometer, and the data used to also calculate a UV protection factor (PF) for each lens brand tested, with a higher value indicating a higher level of protection. The UV-blocking CLs significantly reduced UVC, UVB & UVA transmission and thereby meet the American National Standards Institution standard for class 2 UV blockers: a maximum of 30% transmittance of UVA and 5% transmittance of UVB wavelengths. In contrast, the Durasoft 3, Tutti, and NeoCosmo CLs demonstrated negligible UV-blockage. The Acuvue Define CL offered the greatest protection from UVC (PF=69) and UVB (PF=55), but with only 35% luminous transmittance, while the Freshlook CL (especially gemstone green) offered the best protection from UVA (PF=24) and showed about 55% translucency. Overall, the UV-blocking CLs performed equally well across the UV spectrum. Different colors of Freshlook CL transmitted statistically and clinically significantly different amounts of visible light but similar amounts of UVR. Freshlook and Acuvue Define CLs which are designated as UV-blockers significantly reduced UVR transmission to safe levels whereas Tutti, NeoCosmo and Durasoft 3 did not. Transmission within the Freshlook CL family was more dependent on color in the visible light spectrum, but not in the UV-spectrum, where the gemstone green performing best among the tested colors. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  17. Gravitational lensing and microlensing

    CERN Document Server

    Mollerach, Silvia

    2002-01-01

    This book provides a comprehensive and self-contained exposition of gravitational lensing phenomena. It presents the up-to-date status of gravitational lensing and microlensing, covering the cosmological applications of the observed lensing by galaxies, clusters and the large scale structures, as well as the microlensing searches in the Local Group and its applications to unveil the nature of the galactic dark matter, the search for planetary objects and the distribution of faint stars in our galaxy. Gravitational Lensing and Microlensing is pitched at the level of the graduate student interes

  18. Pulsar lensing geometry

    Science.gov (United States)

    Liu, Siqi; Pen, Ue-Li; Macquart, J.-P.; Brisken, Walter; Deller, Adam

    2016-05-01

    We test the inclined sheet pulsar scintillation model (Pen & Levin) against archival very long baseline interferometry (VLBI) data on PSR 0834+06 and show that its scintillation properties can be precisely reproduced by a model in which refraction occurs on two distinct lens planes. These data strongly favour a model in which grazing-incidence refraction instead of diffraction off turbulent structures is the primary source of pulsar scattering. This model can reproduce the parameters of the observed diffractive scintillation with an accuracy at the percent level. Comparison with new VLBI proper motion results in a direct measure of the ionized interstellar medium (ISM) screen transverse velocity. The results are consistent with ISM velocities local to the PSR 0834+06 sight-line (through the Galaxy). The simple 1-D structure of the lenses opens up the possibility of using interstellar lenses as precision probes for pulsar lens mapping, precision transverse motions in the ISM, and new opportunities for removing scattering to improve pulsar timing. We describe the parameters and observables of this double screen system. While relative screen distances can in principle be accurately determined, a global conformal distance degeneracy exists that allows a rescaling of the absolute distance scale. For PSR B0834+06, we present VLBI astrometry results that provide (for the first time) a direct measurement of the distance of the pulsar. For most of the recycled millisecond pulsars that are the targets of precision timing observations, the targets where independent distance measurements are not available. The degeneracy presented in the lens modelling could be broken if the pulsar resides in a binary system.

  19. Doppler term in the galaxy two-point correlation function: Wide-angle, velocity, Doppler lensing and cosmic acceleration effects

    Science.gov (United States)

    Raccanelli, Alvise; Bertacca, Daniele; Jeong, Donghui; Neyrinck, Mark C.; Szalay, Alexander S.

    2018-03-01

    We study the parity-odd part (that we shall call Doppler term) of the linear galaxy two-point correlation function that arises from wide-angle, velocity, Doppler lensing and cosmic acceleration effects. As it is important at low redshift and at large angular separations, the Doppler term is usually neglected in the current generation of galaxy surveys. For future wide-angle galaxy surveys, however, we show that the Doppler term must be included. The effect of these terms is dominated by the magnification due to relativistic aberration effects and the slope of the galaxy redshift distribution and it generally mimics the effect of the local type primordial non-Gaussianity with the effective nonlinearity parameter fNLeff of a few; we show that this would affect forecasts on measurements of fNL at low-redshift. Our results show that a survey at low redshift with large number density over a wide area of the sky could detect the Doppler term with a signal-to-noise ratio of ∼ 1 - 20, depending on survey specifications.

  20. Effectiveness of Advanced Stay Strong, Stay Healthy in Community Settings

    Directory of Open Access Journals (Sweden)

    Emily M. Crowe MS

    2015-07-01

    Full Text Available The goal of this research was to investigate the effectiveness of the 10-week, University of Missouri (MU Extension strength training program Advanced Stay Strong, Stay Healthy (ASSSH. It was hypothesized that the program can improve strength, balance, agility, and flexibility—all physical measures of falling among seniors. Matched pair t tests were used to compare differences in five physical measures of health, body composition, and percent body fat (%BF. Two-way ANOVA was conducted to examine the age effects on changes in physical health from the start and finish of the exercise program. Following programming, participants significantly improved strength, flexibility, and balance, and significantly reduced %BF ( p < .05. Our data indicate that ASSSH can improve the physical health of senior citizens and can successfully be translated into community practice by MU Extension professionals.

  1. Power Profiles and In Vitro Optical Quality of Scleral Contact Lenses: Effect of the Aperture and Power.

    Science.gov (United States)

    Domínguez-Vicent, Alberto; Esteve-Taboada, Jose Juan; Recchioni, Alberto; Brautaset, Rune

    2017-01-13

    To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture. The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF). A convolution of each lens PSF with an eye-chart image was also computed. The optical power fluctuated less than 0.5 diopters (D) along the optical zone of each lens. However, the optical power obtained for some lenses did not match with its corresponding nominal one, the maximum difference being 0.5 D. In optical quality, small differences were obtained among all lenses within the same design. Although significant differences were obtained among lenses (Pscleral lens. Additionally, the optical quality of both lenses has showed to be independent of the lens power within the same aperture.

  2. Learning through Different Lenses

    Science.gov (United States)

    Jeweler, Sue; Barnes-Robinson, Linda

    2015-01-01

    When parents and teachers help gifted kids use the metaphor "learning through different lenses," amazing things happen: Horizons open up. Ideas are focused. Thoughts are magnified and clarified. They see the big picture. Metaphoric thinking offers new and exciting ways to see the world. Viewing the world through different lenses provides…

  3. Photometry of High-Redshift Gravitationally Lensed Type Ia Supernovae

    Science.gov (United States)

    Haynie, Annastasia

    2018-01-01

    Out of more than 1100 well-identified Type Ia Supernovae, only roughly 10 of them are at z> 1.5. High redshift supernovae are hard to detect but this is made easier by taking advantage of the effects of gravitational lensing, which magnifies objects in the background field of massive galaxy clusters. Supernova Nebra (z= ~1.8), among others, was discovered during observations taken as part of the RELICS survey, which focused on fields of view that experience strong gravitational lensing effects. SN Nebra, which sits behind galaxy cluster Abell 1763, is magnified and therefore appears closer and easier to see than with HST alone. Studying high-redshift supernovae like SN Nebra is an important step towards creating cosmological models that accurately describe the behavior of dark energy in the early Universe. Recent efforts have been focused on improving photometry and the building and fitting of preliminary light curves.

  4. The cold spot as a large void: lensing effect on CMB two and three point correlation functions

    Energy Technology Data Exchange (ETDEWEB)

    Masina, Isabella [Dipartimento di Fisica dell' Università degli Studi di Ferrara and INFN sezione di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); Notari, Alessio, E-mail: masina@fe.infn.it, E-mail: alessio.notari@cern.ch [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)

    2009-07-01

    The ''Cold Spot'' in the CMB sky could be due to the presence of an anomalous huge spherical underdense region — a ''Void'' — of a few hundreds Mpc/h radius. Such a structure would have an impact on the CMB two-point (power spectrum) and three-point (bispectrum) correlation functions not only at low l, but also at high l through Lensing, which is a unique signature of a Void. Modeling such an underdensity with an LTB metric, we show that for the power spectrum the effect should be visible already in the WMAP data only if the Void radius is at least L ∼> 1 Gpc/h, while it will be visible by the Planck satellite if L ∼> 800 Mpc/h. We also speculate that this could be linked to the high-l detection of an hemispherical power asymmetry in the sky. Moreover, there should be non-zero correlations in the non-diagonal two-point function. For the bispectrum, the effect becomes important for squeezed triangles with two very high l's: this signal can be detected by Planck if the Void radius is at least L ∼> 400 Mpc/h, while higher resolution experiments should be able to probe the entire parameter space. We have also estimated the contamination of the primordial non-Gaussianity f{sub NL} due to this signal, which turns out to be negligible.

  5. The Cold Spot as a Large Void: Lensing Effect on CMB Two and Three Point Correlation Functions

    CERN Document Server

    Masina, Isabella

    2009-01-01

    The "Cold Spot" in the CMB sky could be due to the presence of an anomalous huge spherical underdense region - a "Void" - of a few hundreds Mpc/h radius. Such a structure would have an impact on the CMB two-point (power spectrum) and three-point (bispectrum) correlation functions not only at low-l, but also at high-l through Lensing, which is a unique signature of a Void. Modeling such an underdensity with an LTB metric, we show that for the power spectrum the effect should be visible already in the WMAP data if the Void radius is at least 400 Mpc/h, while it will be visible by the Planck satellite for any Void radius. We also speculate that this could be linked to the high-l detection of an hemispherical power asymmetry in the sky. Moreover, there should be non-zero correlations in the non-diagonal two-point function. For the bispectrum, the effect becomes important for squeezed triangles with two very high-l's: this signal can be detected by Planck if the Void radius is at least 600 Mpc/h. We have also esti...

  6. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab /SLAC /Fermilab /Serpukhov, IHEP /Novosibirsk, IYF /Serpukhov, IHEP /Fermilab

    2008-08-01

    The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  7. Electron Lenses for particle collimation in LHC

    CERN Document Server

    Shiltsev, V

    2008-01-01

    Electron Lenses built and installed in Tevatron have proven themselves as safe and very reliable instruments which can be effectively used in hadron collider operation for a number of applications, including compensation of beam-beam effects , DC beam removal from abort gaps , as a diagnostic tool. In this presentation we – following original proposal – consider in more detail a possibility of using electron lenses with hollow electron beam for ion and proton collimation in LHC.

  8. Effect of random charge fluctuation on strongly coupled dusty Plasma

    Science.gov (United States)

    Issaad, M.; Rouiguia, L.; Djebli, M.

    2008-09-01

    Modeling the interaction between particles is an open issue in dusty plasma. We dealt with strongly coupled dust particles in two dimensional confined system. For small number of clusters, we investigate the effect of random charge fluctuation on background configuration. The study is conducted for a short rang as well as a long rang potential interaction. Numerical simulation is performed using Monte-Carlo simulation in the presence of parabolic confinement and at low temperature. We have studied the background configurations for a dust particles with constant charge and in the presence of random charge fluctuation due to the discrete nature of charge carriers. The latter is studied for a positively charged dust when the dominant charging process is due to photo-emission from the dust surface. It is found, for small classical cluster consisting of small number of particles, short rang potential gives the same result as long rang one. It is also found that the random charge fluctuation affect the background configurations.

  9. Halo Pressure Profile through the Skew Cross-power Spectrum of the Sunyaev–Zel’dovich Effect and CMB Lensing in Planck

    Energy Technology Data Exchange (ETDEWEB)

    Timmons, Nicholas; Cooray, Asantha; Feng, Chang [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Keating, Brian [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States)

    2017-11-01

    We measure the cosmic microwave background (CMB) skewness power spectrum in Planck , using frequency maps of the HFI instrument and the Sunyaev–Zel’dovich (SZ) component map. The two-to-one skewness power spectrum measures the cross-correlation between CMB lensing and the thermal SZ effect. We also directly measure the same cross-correlation using the Planck CMB lensing map and the SZ map and compare it to the cross-correlation derived from the skewness power spectrum. We model fit the SZ power spectrum and CMB lensing–SZ cross-power spectrum via the skewness power spectrum to constrain the gas pressure profile of dark matter halos. The gas pressure profile is compared to existing measurements in the literature including a direct estimate based on the stacking of SZ clusters in Planck .

  10. Sunyaev-Zel'dovich Effect and X-ray Scaling Relations from Weak-Lensing Mass Calibration of 32 SPT Selected Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, J.P.; et al.

    2017-11-14

    Uncertainty in the mass-observable scaling relations is currently the limiting factor for galaxy cluster based cosmology. Weak gravitational lensing can provide a direct mass calibration and reduce the mass uncertainty. We present new ground-based weak lensing observations of 19 South Pole Telescope (SPT) selected clusters and combine them with previously reported space-based observations of 13 galaxy clusters to constrain the cluster mass scaling relations with the Sunyaev-Zel'dovich effect (SZE), the cluster gas mass $M_\\mathrm{gas}$, and $Y_\\mathrm{X}$, the product of $M_\\mathrm{gas}$ and X-ray temperature. We extend a previously used framework for the analysis of scaling relations and cosmological constraints obtained from SPT-selected clusters to make use of weak lensing information. We introduce a new approach to estimate the effective average redshift distribution of background galaxies and quantify a number of systematic errors affecting the weak lensing modelling. These errors include a calibration of the bias incurred by fitting a Navarro-Frenk-White profile to the reduced shear using $N$-body simulations. We blind the analysis to avoid confirmation bias. We are able to limit the systematic uncertainties to 6.4% in cluster mass (68% confidence). Our constraints on the mass-X-ray observable scaling relations parameters are consistent with those obtained by earlier studies, and our constraints for the mass-SZE scaling relation are consistent with the the simulation-based prior used in the most recent SPT-SZ cosmology analysis. We can now replace the external mass calibration priors used in previous SPT-SZ cosmology studies with a direct, internal calibration obtained on the same clusters.

  11. Inverting Gravitational Lenses

    Science.gov (United States)

    Newbury, P. R.; Spiteri, R. J.

    2002-02-01

    Gravitational lensing provides a powerful tool to study a number of fundamental questions in astrophysics. Fortuitously, one can begin to explore some non-trivial issues associated with this phenomenon without a lot of very sophisticated mathematics, making an elementary treatment of this topic tractable even to senior undergraduates. In this paper, we give a relatively self-contained outline of the basic concepts and mathematics behind gravitational lensing as a recent and exciting topic for courses in mathematical modeling or scientific computing. To this end, we have designed and made available some interactive software to aid in the simulation and inversion of gravitational lenses in a classroom setting.

  12. Stress-Detection Lenses

    Science.gov (United States)

    1996-01-01

    An Ames Research Center scientist invented an infrared lens used in sunglasses to filter out ultraviolet rays. This product finds its origins in research for military enemy detection. Through a Space Act Agreement, Optical Sales Corporation introduced the Hawkeye Lenses not only as sunglasses but as plant stress detection lenses. The lenses enhance the stressed part of the leaf, which has less chlorophyll than healthy leaves, through dyes that filter out certain wavelengths of light. Plant stress is visible earlier, at a stage when something can be done to save the plants.

  13. Study of the Effectiveness of Multipurpose Solutions on the Bacterial Disinfection of Silicone Hydrogel Contact Lenses In Vitro.

    Science.gov (United States)

    Correa, Priscila C; Lui, Aline C F; Silva, Cely B; Gracitelli, Carolina P B; Mimica, Lycia M; Sasagawa, Suzethe M; Netto, Adamo L

    2017-10-12

    To assess the antimicrobial effectiveness of multipurpose solutions in regard to the disinfection of silicone hydrogel contact lenses (CL) using a study of clinical bacterial isolates from ocular material. Three multipurpose solutions (solution A: polyhexamethylene biguanide 0.00025 g/100 mL; solution B: polyquaternary-1 0.001% and myristamidopropyl dimethylamine 0.0006%; and solution C: polyaminopropyl biguanide 0.00013% and polyquaternary 0.0001%) were used as a 3-phase disinfection on silicone hydrogel CL contaminated with bacteria from clinical isolates that were divided into five groups (group 1: Pseudomonas aeruginosa; group 2: Staphylococcus aureus; group 3: Staphylococcus epidermidis; group 4: Streptococcus spp; and group 5: enterobacteria). No differences were observed between the 24- and 48-hr measurements in any of the samples, and the positivity of microorganisms in T0 was 100% for all solutions; it was 0% in T3. Therefore, only steps T1 (rubbing followed by rinsing) and T2 (rubbing followed by rinsing and immersion of CL into solution) were considered for analysis at the 24-hr measurement time. Throughout the phases, a decrease in the number of bacteria was observed, culminating in the elimination (no recovery) of all microorganisms in the three solutions. At the end of the proposed process, the tested solutions were effective.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

  14. Can possible toxic effect of ultraviolet-A after corneal cross-linking be prevented? In vitro transmittance study of contact lenses at 370 nm wavelength.

    Science.gov (United States)

    Bilgihan, Kamil; Yuksel, Erdem; Deniz, Nuriye Gokcen; Yuksel, Nilay

    2015-01-01

    Corneal collagen cross linking (CCL) with ultraviolet A (UVA) has been proposed as a treatment for the progression of corneal ectasia associated with keratoconus and post-laser-assisted in situ keratomileusis (LASIK) ectasia. Despite the reports about safety of procedure, we consider that UVA of sunlight can effect riboflavin saturated and de-epitelizated cornea early after CCL. To evaluate the UVA blockage capability of 11 different silicone hydrogel contact lenses which are widely used after CCL treatment. Eleven different silicone hydrogel and daily disposable contact lenses were evaluated. The UVA light at 365 nm wavelength for UVA source and UV light meter to measure UVA radiation were used. 3, 9 and 18 mW/cm(2) power of UV radiance was applied centrally to the each type of contact lenses. The power of UVA transmittance for each radiance and percentage of blockage were evaluated for each brand. Also, protection factor (PF) was calculated. The senofilcon A and narafilcon A had the highest blockage and lowest transmittance (p = 0.02). PF was significantly higher in the senofilcon A and narafilcon A at 3, 9 and 18 mW/cm(2) (p = 0.0001). And also, the hilafilcon B, filcon IV, nelfilcon A, enfilcon A, lotrafilcon A and lotrafilcon B had the highest UVA transmittance. The narafilcon A and the senofilcon A may be a good options for epithelial healing after CCL procedure to protect the cornea from UVA of sunlight. And also, the hilafilcon B, filcon IV, nelfilcon A, enfilcon A, lotrafilcon A and lotrafilcon B contact lenses that have high-UVA transmittance feature can be a treatment choice for contact lens-assisted CCL technique in thin corneas.

  15. Gravitational lensing of quasars

    CERN Document Server

    Eigenbrod, Alexander

    2013-01-01

    The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher r...

  16. Braneworld Black Hole Gravitational Lensing

    International Nuclear Information System (INIS)

    Liang Jun

    2017-01-01

    A class of braneworld black holes, which I called as Bronnikov–Melnikov–Dehen (BMD) black holes, are studied as gravitational lenses. I obtain the deflection angle in the strong deflection limit, and further calculate the angular positions and magnifications of relativistic images as well as the time delay between different relativistic images. I also compare the results with those obtained for Schwarzschild and two braneworld black holes, i.e., the tidal Reissner-Nordström (R-N) and the Casadio–Fabbri–Mazzacurati (CFM) black holes. (paper)

  17. Weakly oval electron lense

    International Nuclear Information System (INIS)

    Daumenov, T.D.; Alizarovskaya, I.M.; Khizirova, M.A.

    2001-01-01

    The method of the weakly oval electrical field getting generated by the axially-symmetrical field is shown. Such system may be designed with help of the cylindric form coaxial electrodes with the built-in quadrupole duplet. The singularity of the indicated weakly oval lense consists of that it provides the conducting both mechanical and electronic adjustment. Such lense can be useful for elimination of the near-axis astigmatism in the electron-optical system

  18. Certain relativistic effects due to strong electromagnetic fields in plasmas

    International Nuclear Information System (INIS)

    Tsintsadze, N.L.

    1974-01-01

    It is shown that the propagation of a strong electromagnetic wave in an electron plasma can lead to a generation of a constant electron current along the direction of propagation and to a large increase in the average electron density. (Auth.)

  19. Gravitational lensing by rotating wormholes

    Science.gov (United States)

    Jusufi, Kimet; Ã-vgün, Ali

    2018-01-01

    In this paper the deflection angle of light by a rotating Teo wormhole spacetime is calculated in the weak limit approximation. We mainly focus on the weak deflection angle by revealing the gravitational lensing as a partially global topological effect. We apply the Gauss-Bonnet theorem (GBT) to the optical geometry osculating the Teo-Randers wormhole optical geometry to calculate the deflection angle. Furthermore we find the same result using the standard geodesic method. We have found that the deflection angle can be written as a sum of two terms, namely the first term is proportional to the throat of the wormhole and depends entirely on the geometry, while the second term is proportional to the spin angular momentum parameter of the wormhole. A direct observation using lensing can shed light and potentially test the nature of rotating wormholes by comparing with the black holes systems.

  20. The effect of the density mismatch of liquids on scaling down steerable liquid lenses

    NARCIS (Netherlands)

    Farcy, G.; Deladi, S.; Suijver, J.F.

    2007-01-01

    This report describes the results of the investigations on the effect of the gravity on downscaling the liquid lens. The configuration of the lens was chosen so that it enables steering of the interface between the two immiscible liquids in a flat position by electro wetting, which is important for

  1. Effective Field Theories and Strong Interactions. Final Technical Report

    International Nuclear Information System (INIS)

    Fleming, Sean

    2011-01-01

    The framework of Effective Field Theories (EFTs) allows us to describe strong interactions in terms of degrees of freedom relevant to the energy regimes of interest, in the most general way consistent with the symmetries of QCD. Observables are expanded systematically in powers of M lo /M hi , where M lo (M hi ) denotes a low-(high-)energy scale. This organizational principle is referred to as 'power counting'. Terms of increasing powers in the expansion parameter are referred to as leading order (LO), next-to-leading order (NLO), etc. Details of the QCD dynamics not included explicitly are encoded in interaction parameters, or 'low-energy constants' (LECs), which can in principle be calculated from an explicit solution of QCD - for example via lattice simulations- but can also be determined directly from experimental data. QCD has an intrinsic scale M QCD ≅ 1 GeV, at which the QCD coupling constant α s (M QCD ) becomes large and the dynamics becomes non-perturbative. As a consequence M QCD sets the scale for the masses of most hadrons, such as the nucleon mass m N ≅ 940 MeV. EFTs can roughly be divided into two categories: those that can be matched onto QCD in perturbation theory, which we call high-energy EFTs, and those that cannot be matched perturbatively, which we call low-energy EFTs. In high-energy EFTs, M QCD typically sets the low-energy scale, and all the dynamics associated with this scale reside in matrix elements of EFT operators. These non-perturbative matrix elements are the LECs and are also referred to as long-distance contributions. Each matrix element is multiplied by a short-distance coefficient, which contains the dynamics from the high scale M hi . Since M hi >> M QCD , α s (M hi ) hi ∼ M Q , the heavy-quark mass, and in addition to M QCD there are low scales associated with the typical relative momentum ∼ M Q v and energy ∼ M Q v 2 of the heavy quarks. Depending on the sizes of M Q and the heavy-quark velocity v these scales can

  2. Optical Dispersion, Permittivity Spectrum and Thermal-Lensing Effect in Nickel-Doped Zinc Sulfide Nanoparticles

    Science.gov (United States)

    Abbasi, F.; Koushki, E.; Majles Ara, M. H.; Sahraei, R.

    2017-11-01

    In this paper, Ni-doped ZnS (ZnS:Ni2+) nanoparticles (NPs) have been prepared through a chemical method. The average size of the particle is 45 nm. Thin films of the particles have been prepared by using the spin-coating method. The linear and nonlinear optical properties of Ni-doped ZnS thin films and the colloidal solution of them have been studied widely. Using a precise numerical method, the refractive index curve (dispersion curve), absorption coefficient and optical permittivity of Ni-doped ZnS film have been obtained. Using these values, the absorption coefficient of the colloidal solution of Ni-doped ZnS particles has been simulated and compared with experimental results. Finally, using the z-scan method at low laser irradiation, the thermo-optical effect has been studied and the nonlinear refractive index due to this effect has been reported.

  3. How strong and generalisable is the Generation Y effect?

    DEFF Research Database (Denmark)

    Mueller, Simone; Remaud, Hervé; Chabin, Yann

    2011-01-01

    alcoholic beverage consumption. A number of noticeable differences appeared between countries: wine involvement and consumption increases with age in traditional European wine markets, while they decrease in North America; environmental concerns and purchase channel usage hardly differ between generations......Purpose – This study aims to investigate how strongly Generation Y consumers differ in their values, attitudes and wine and alcoholic beverage consumption behaviour from older generations. The comparison spans seven culturally different markets. Design/methodology/approach – Large representative...

  4. On the Effect of the Cosmological Expansion on the Gravitational Lensing by a Point Mass

    Directory of Open Access Journals (Sweden)

    Oliver F. Piattella

    2016-10-01

    Full Text Available We analyse the effect of the cosmological expansion on the deflection of light caused by a point mass, adopting the McVittie metric as the geometrical description of a point-like lens embedded in an expanding universe. In the case of a generic, non-constant Hubble parameter, H, we derive and approximately solve the null geodesic equations, finding an expression for the bending angle δ, which we expand in powers of the mass-to-closest approach distance ratio and of the impact parameter-to-lens distance ratio. It turns out that the leading order of the aforementioned expansion is the same as the one calculated for the Schwarzschild metric and that cosmological corrections contribute to δ only at sub-dominant orders. We explicitly calculate these cosmological corrections for the case of the H constant and find that they provide a correction of order 10−11 on the lens mass estimate.

  5. Spin effects in strong-field laser-electron interactions

    International Nuclear Information System (INIS)

    Ahrens, S; Bauke, H; Müller, T-O; Villalba-Chávez, S; Müller, C

    2013-01-01

    The electron spin degree of freedom can play a significant role in relativistic scattering processes involving intense laser fields. In this contribution we discuss the influence of the electron spin on (i) Kapitza-Dirac scattering in an x-ray laser field of high intensity, (ii) photo-induced electron-positron pair production in a strong laser wave and (iii) multiphoton electron-positron pair production on an atomic nucleus. We show that in all cases under consideration the electron spin can have a characteristic impact on the process properties and their total probabilities. To this end, spin-resolved calculations based on the Dirac equation in the presence of an intense laser field are performed. The predictions from Dirac theory are also compared with the corresponding results from the Klein-Gordon equation.

  6. The effects of assembly bias on the inference of matter clustering from galaxy-galaxy lensing and galaxy clustering

    Science.gov (United States)

    McEwen, Joseph E.; Weinberg, David H.

    2018-04-01

    The combination of galaxy-galaxy lensing (GGL) and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modeling can extend the approach down to nonlinear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with large scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older halos affects the cutoff of the mean occupation function for central galaxies, with halos in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We introduce an extended, environment dependent HOD (EDHOD) prescription to describe these results and fit galaxy correlation measurements. Crucially, we find that the galaxy-matter cross-correlation coefficient, rgm(r) ≡ ξgm(r) . [ξmm(r)ξgg(r)]-1/2, is insensitive to assembly bias on scales r ≳ 1 h^{-1} Mpc, even though ξgm(r) and ξgg(r) are both affected individually. We can therefore recover the correct ξmm(r) from the HW13 galaxy-galaxy and galaxy-matter correlations using either a standard HOD or EDHOD fitting method. For Mr ≤ -19 or Mr ≤ -20 samples the recovery of ξmm(r) is accurate to 2% or better. For a sample of red Mr ≤ -20 galaxies we achieve 2% recovery at r ≳ 2 h^{-1} Mpc with EDHOD modeling but lower accuracy at smaller scales or with a standard HOD fit. Most of our mock galaxy samples are consistent with rgm = 1 down to r = 1h-1Mpc, to within the uncertainties set by our finite simulation volume.

  7. Radiation effects on relativistic electrons in strong external fields

    International Nuclear Information System (INIS)

    Iqbal, Khalid

    2013-01-01

    The effects of radiation of high energy electron beams are a major issue in almost all types of charged particle accelerators. The objective of this thesis is both the analytical and numerical study of radiation effects. Due to its many applications the study of the self force has become a very active and productive field of research. The main part of this thesis is devoted to the study of radiation effects in laser-based plasma accelerators. Analytical models predict the existence of radiation effects. The investigation of radiation reaction show that in laser-based plasma accelerators, the self force effects lower the energy gain and emittance for moderate energies electron beams and increase the relative energy spread. However, for relatively high energy electron beams, the self radiation and retardation (radiation effects of one electron on the other electron of the system) effects increase the transverse emittance of the beam. The energy gain decreases to even lower value and relative energy spread increases to even higher value due to high radiation losses. The second part of this thesis investigates with radiation reaction in focused laser beams. Radiation effects are very weak even for high energy electrons. The radiation-free acceleration and the simple practical setup make direct acceleration in a focused laser beam very attractive. The results presented in this thesis can be helpful for the optimization of future electron acceleration experiments, in particular in the case of laser-plasma accelerators.

  8. Effective magnetic moment of neutrinos in strong magnetic fields

    CERN Document Server

    Pérez, A; Masood, S S; Gaitan, R; Rodríguez, S

    2002-01-01

    In this paper we compute the effective magnetic moment of neutrinos propagating in dense high magnetized medium. Taking typical values of magnetic field and densities of astrophysical objects (such as the cores of supernovae and neutron stars) we obtain an effective type of dipole magnetic moment in agreement with astrophysical and cosmological bounds. (Author)

  9. Gravitational lensing of gravitational waves from merging neutron star binaries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun; Stebbins, Albert; Turner, Edwin L.

    1996-05-01

    We discuss the gravitational lensing of gravitational waves from merging neutron star binaries, in the context of advanced LIGO type gravitational wave detectors. We consider properties of the expected observational data with cut on the signal-to-noise ratio \\rho, i.e., \\rho>\\rho_0. An advanced LIGO should see unlensed inspiral events with a redshift distribution with cut-off at a redshift z_{\\rm max} < 1 for h \\leq 0.8. Any inspiral events detected at z>z_{\\rm max} should be lensed. We compute the expected total number of events which are present due to gravitational lensing and their redshift distribution for an advanced LIGO in a flat Universe. If the matter fraction in compact lenses is close to 10\\%, an advanced LIGO should see a few strongly lensed events per year with \\rho >5.

  10. The Connect Effect Building Strong Personal, Professional, and Virtual Networks

    CERN Document Server

    Dulworth, Michael

    2008-01-01

    Entrepreneur and executive development expert Mike Dulworth's THE CONNECT EFFECT provides readers with a simple framework and practical tools for developing that crucial competitive advantage: a high-quality personal, professional/organizational and virtual network.

  11. CMB-lensing beyond the Born approximation

    International Nuclear Information System (INIS)

    Marozzi, Giovanni; Fanizza, Giuseppe; Durrer, Ruth; Dio, Enea Di

    2016-01-01

    We investigate the weak lensing corrections to the cosmic microwave background temperature anisotropies considering effects beyond the Born approximation. To this aim, we use the small deflection angle approximation, to connect the lensed and unlensed power spectra, via expressions for the deflection angles up to third order in the gravitational potential. While the small deflection angle approximation has the drawback to be reliable only for multipoles ℓ ∼< 2500, it allows us to consistently take into account the non-Gaussian nature of cosmological perturbation theory beyond the linear level. The contribution to the lensed temperature power spectrum coming from the non-Gaussian nature of the deflection angle at higher order is a new effect which has not been taken into account in the literature so far. It turns out to be the leading contribution among the post-Born lensing corrections. On the other hand, the effect is smaller than corrections coming from non-linearities in the matter power spectrum, and its imprint on CMB lensing is too small to be seen in present experiments.

  12. Effective bounds on strong unicity in L1-approximation

    DEFF Research Database (Denmark)

    Kohlenbach, Ulrich; Oliva, Paulo B.

    In this paper we present another case study in the general project of Proof Mining which means the logical analysis of prima facie non-effective proofs with the aim of extracting new computationally relevant data. We use techniques based on monotone functional interpretation (developed in [17]) t...

  13. Properties of light-absorbing aerosols in the Nagoya urban area, Japan, in August 2011 and January 2012: Contributions of brown carbon and lensing effect

    Science.gov (United States)

    Nakayama, Tomoki; Ikeda, Yuka; Sawada, Yuuki; Setoguchi, Yoshitaka; Ogawa, Shuhei; Kawana, Kaori; Mochida, Michihiro; Ikemori, Fumikazu; Matsumoto, Kiyoshi; Matsumi, Yutaka

    2014-11-01

    The optical properties of aerosols at 405 and 781 nm were measured in an urban site in Nagoya, Japan, in August 2011 and in January 2012 using a photoacoustic spectrometer. Comparison of the absorption coefficient at 781 nm of aerosols that did and did not pass through a thermo-denuder showed that an increase in black carbon (BC) light absorption due to the coating of non-refractory materials (i.e., the lensing effect) was small (on average, 10%) in August and negligible in January. The effective density distributions for the particles that did and did not pass through the thermo-denuder, which were measured simultaneously in August, suggested that the majority of BC particles sampled had a minimal coating. The small lensing effect observed can be explained partly by assuming that a large portion of non-refractory materials was mixed externally with BC. The contribution of direct light absorption by organic matter (OM) that vaporized at temperatures below 300°C to the total light absorption at 405 nm was negligible in August, but those by OM that vaporized below 300 and 400°C averaged 11 and 17%, respectively, in January. The larger contribution of light-absorbing OM in January is likely due to the greater contribution of OM originating from the burning of biomass, including biofuel and agricultural residue, in Japan, northern China, or Siberia, during the winter.

  14. Weak lensing of the Lyman-alpha forest

    Science.gov (United States)

    Croft, Rupert A. C.; Romeo, Alessandro; Metcalf, R. Benton

    2018-03-01

    The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyα forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak gravitional lensing of the Lyα forest could be measured using similar techniques that have been applied to the lensed Cosmic Microwave Background, and which have also been proposed for application to spectral data from 21cm radio telescopes. As with 21cm data, the forest has the advantage of spectral information, potentially yielding many lensed "slices" at different redshifts. We perform an illustrative idealized test, generating a high resolution angular grid of quasars (of order arcminute separation), and lensing the Lyα forest spectra at redshifts z = 2 - 3 using a foreground density field. We find that standard quadratic estimators can be used to reconstruct images of the foreground mass distribution at z ˜ 1. There currently exists a wealth of Lyα forest data from quasar and galaxy spectral surveys, with smaller sightline separations expected in the future. Lyα forest lensing is sensitive to the foreground mass distribution at redshifts intermediate between CMB lensing and galaxy shear, and avoids the difficulties of shape measurement associated with the latter. With further refinement and application of mass reconstruction techniques, weak gravitational lensing of the high redshift Lyα forest may become a useful new cosmological probe.

  15. Strong delayed interactive effects of metal exposure and warming

    DEFF Research Database (Denmark)

    Debecker, Sara; Dinh, Khuong Van; Stoks, Robby

    2017-01-01

    As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species......’ ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and lowlatitude populations. By integrating these mechanisms...... was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies...

  16. The protective effects of l-carnitine and vitamin e in rat lenses in irradiation-induced oxidative injury

    International Nuclear Information System (INIS)

    Taysi, S.; Okumus, S.; Ezirmik, S.; Uzun, N.; Yilmaz, A.; Akyuz, M.; Tekelioglu, U.; Dirier, A.; Al, B.

    2011-01-01

    Objectives. The aim of this study was to evaluate the antioxidant role of L-carnitine (LC) and vitamin E against radiation-induced cataracts in rat lenses after total cranial irradiation with a single 5 Gray (Gy) dose of gamma irradiation. Material and Methods. Thirty two Sprague-Dawley rats were used for the experiment. The control group did not receive LC and vitamin E or irradiation but received both 0.1 ml physiological saline intraperitoneally and sham irradiation. The irradiation (IR) group received 5 Gy gamma irradiation to the total cranium as a single dose plus 0.1 ml physiological saline intraperitoneally. The IR plus vitamin E group received irradiation to total cranium plus 10 mg/kg/day vitamin E intraperitoneally. The IR plus LC group received irradiation to total cranium plus 100 mg/kg/day LC intraperitoneally. Biochemical parameters measured in murine lenses were carried out using spectrophotometric techniques. Results. Total superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA), glutathione-S-transferase (GST) and glutathione reductase (GRD) activities, significantly increased in the control, IR plus vitamin E and LC plus IR groups when compared with the IR only group. Lens TSSA and NSSA activities in the control group were significantly increased compared to that of the IR only group, but decreased compared to those of the IR plus vitamin E and IR plus LC groups. Lens xanthine oxidase (XO) activity in the IR group significantly increased compared to those of other groups. Conclusions. Results show that LC and vitamin E prevented oxidative stress by scavenging free radicals generated by ionizing radiation in rat lenses. (authors)

  17. Biocompatibility of Intraocular Lenses.

    Science.gov (United States)

    Özyol, Pelin; Özyol, Erhan; Karel, Fatih

    2017-08-01

    The performance of an intraocular lens is determined by several factors such as the surgical technique, surgical complications, intraocular lens biomaterial and design, and host reaction to the lens. The factor indicating the biocompatibility of an intraocular lens is the behavior of inflammatory and lens epithelial cells. Hence, the biocompatibility of intraocular lens materials is assessed in terms of uveal biocompatibility, based on the inflammatory foreign-body reaction of the eye against the implant, and in terms of capsular biocompatibility, determined by the relationship of the intraocular lens with residual lens epithelial cells within the capsular bag. Insufficient biocompatibility of intraocular lens materials may result in different clinical entities such as anterior capsule opacification, posterior capsule opacification, and lens epithelial cell ongrowth. Intraocular lenses are increasingly implanted much earlier in life in cases such as refractive lens exchange or pediatric intraocular lens implantation after congenital cataract surgery, and these lenses are expected to exhibit maximum performance for many decades. The materials used in intraocular lens manufacture should, therefore, ensure long-term uveal and capsular biocompatibility. In this article, we review the currently available materials used in the manufacture of intraocular lenses, especially with regard to their uveal and capsular biocompatibility, and discuss efforts to improve the biocompatibility of intraocular lenses.

  18. Effect of strong fragrance on olfactory detection threshold.

    Science.gov (United States)

    Fasunla, Ayotunde James; Douglas, David Dayo; Adeosun, Aderemi Adeleke; Steinbach, Silke; Nwaorgu, Onyekwere George Benjamin

    2014-09-01

    To assess the olfactory threshold of healthy volunteers at the University College Hospital, Ibadan and to investigate the effect of perfume on their olfactory detection thresholds. A quasi-experimental study on olfactory detection thresholds of healthy volunteers from September 2013 to November 2013. Tertiary health institution. A structured questionniare was administered to the participants in order to obtain information on sociodemographics, occupation, ability to perceive smell, use of perfume, effects of perfume on appetite and self-confidence, history of allergy, and previous nasal surgery. Participants subjectively rated their olfactory performance. Subsequently, they had olfactory detection threshold testing done at baseline and after exposure to perfume with varied concentrations of n-butanol in a forced triple response and staircase fashion. Healthy volunteers, 37 males and 63 females, were evaluated. Their ages ranged from 19 to 59 years with a mean of 31 years ± 8. Subjectively, 94% of the participants had excellent olfactory function. In the pre-exposure forced triple response, 88% were able to detect the odor at ≤.25 mmol/l concentration while in the post-exposure forced triple response, only 66% were able to detect the odor at ≤.25 mmol/l concentration. There is also a statistical significant difference in the olfactory detection threshold score between the pre-exposure and post-exposure period in the participants (P fragrances affects the olfactory detection threshold. Therefore patients and clinicians should be aware of this and its effects on the outcome of test of olfaction. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

  19. Stirling engines using working fluids with strong real gas effects

    International Nuclear Information System (INIS)

    Invernizzi, Costante M.

    2010-01-01

    Real gas effects typical of the critical region of working fluids are a powerful tool to increase the energy performances of Stirling cycles, mainly at low top temperatures. To carry out the compression near the critical region the working fluids must have a critical temperature near environmental conditions and the use of organic working substances (pure or in suitable mixtures) as a matter of fact begins compulsory. The moderate thermal stability of the organic working fluids limits the maximum temperatures to 300-400 deg. C and as a consequence, the achievable cycles efficiencies result rather low. Carbon dioxide, with a critical temperature of 31 deg. C, is, among the traditionally inorganic gases, an exception and is considered here in comparison with organic substances. But the good thermodynamics of the cycles allows, in the considered cases, conversion efficiencies of about 20%, with good specific powers. The good energy performance of real gas Stirling cycles is obtained at the cost of high maximum cycle pressure, in the range of at least 100-300 bar. These high pressures nevertheless have large positive effects on the heat power transferred per unit of pumping mechanical power, and the low top temperatures have a positive influence on the material problems for the hottest engine parts.

  20. Strong surface effect on direct bulk flexoelectric response in solids

    International Nuclear Information System (INIS)

    Yurkov, A. S.; Tagantsev, A. K.

    2016-01-01

    In the framework of a continuum theory, it is shown that the direct bulk flexoelectric response of a finite sample essentially depends on the surface polarization energy, even in the thermodynamic limit where the body size tends to infinity. It is found that a modification of the surface energy can lead to a change in the polarization response by a factor of two. The origin of the effect is an electric field produced by surface dipoles induced by the strain gradient. The unexpected sensitivity of the polarization response to the surface energy in the thermodynamic limit is conditioned by the fact that the moments of the surface dipoles may scale as the body size

  1. Electron lenses for super-colliders

    CERN Document Server

    Shiltsev, Vladimir D

    2016-01-01

    This book provides a comprehensive overview of the operating principles and technology of electron lenses in supercolliders.  Electron lenses are a novel instrument for high energy particle accelerators, particularly for the energy-frontier superconducting hadron colliders, including the Tevatron, RHIC, LHC and future very large hadron colliders.  After reviewing the issues surrounding beam dynamics in supercolliders, the book offers an introduction to the electron lens method and its application.  Further chapters describe the technology behind the electron lenses which have recently been proposed, built and employed for compensation of beam-beam effects and for collimation of high-energy high-intensity beams, for compensation of space-charge effects and several other applications in accelerators. The book will be an invaluable resource for those involved in the design, construction and operation of the next generation of hadron colliders.

  2. Weak Weak Lensing : How Accurately Can Small Shears be Measured?

    NARCIS (Netherlands)

    Kuijken, K.

    2006-01-01

    Abstract: Now that weak lensing signals on the order of a percent are actively being searched for (cosmic shear, galaxy-galaxy lensing, large radii in clusters...) it is important to investigate how accurately weak shears can be determined. Many systematic effects are present, and need to be

  3. Potential effects of sea-level rise on the depth to saturated sediments of the Sagamore and Monomoy flow lenses on Cape Cod, Massachusetts

    Science.gov (United States)

    Walter, Donald A.; McCobb, Timothy D.; Masterson, John P.; Fienen, Michael N.

    2016-05-25

    In 2014, the U.S. Geological Survey, in cooperation with the Association to Preserve Cape Cod, the Cape Cod Commission, and the Massachusetts Environmental Trust, began an evaluation of the potential effects of sea-level rise on water table altitudes and depths to water on central and western Cape Cod, Massachusetts. Increases in atmospheric and oceanic temperatures arising, in part, from the release of greenhouse gases likely will result in higher sea levels globally. Increasing water table altitudes in shallow, unconfined coastal aquifer systems could adversely affect infrastructure—roads, utilities, basements, and septic systems—particularly in low-lying urbanized areas. The Sagamore and Monomoy flow lenses on Cape Cod are the largest and most populous of the six flow lenses that comprise the region’s aquifer system, the Cape Cod glacial aquifer. The potential effects of sea-level rise on water table altitude and depths to water were evaluated by use of numerical models of the region. The Sagamore and Monomoy flow lenses have a number of large surface water drainages that receive a substantial amount of groundwater discharge, 47 and 29 percent of the total, respectively. The median increase in the simulated water table altitude following a 6-foot sea-level rise across both flow lenses was 2.11 feet, or 35 percent when expressed as a percentage of the total sea-level rise. The response is nearly the same as the sea-level rise (6 feet) in some coastal areas and less than 0.1 foot near some large inland streams. Median water table responses differ substantially between the Sagamore and Monomoy flow lenses—at 29 and 49 percent, respectively—because larger surface water discharge on the Sagamore flow lens results in increased dampening of the water table response than in the Monomoy flow lens. Surface waters dampen water table altitude increases because streams are fixed-altitude boundaries that cause hydraulic gradients and streamflow to increase as sea

  4. Learning unit: Thin lenses

    Science.gov (United States)

    Nita, L.-S.

    2012-04-01

    Learning unit: Thin lenses "Why objects seen through lenses are sometimes upright and sometimes reversed" Nita Laura Simona National College of Arts and Crafts "Constantin Brancusi", Craiova, Romania 1. GEOMETRIC OPTICS. 13 hours Introduction (models, axioms, principles, conventions) 1. Thin lenses (Types of lenses. Defining elements. Path of light rays through lenses. Image formation. Required physical quantities. Lens formulas). 2. Lens systems (Non-collated lenses. Focalless systems). 3. Human eye (Functioning as an optical system. Sight defects and their corrections). 4. Optical instruments (Characteristics exemplified by a magnifying glass. Paths of light rays through a simplified photo camera. Path of light rays through a classical microscope) (Physics curriculum for the IXth grade/ 2011). This scenario exposes a learning unit based on experimental sequences (defining specific competencies), as a succession of lessons started by noticing a problem whose solution assumes the setup of an experiment under laboratory conditions. Progressive learning of theme objectives are realised with sequential experimental steps. The central cognitive process is the induction or the generalization (development of new knowledge based on observation of examples or counterexamples of the concept to be learnt). Pupil interest in theme objectives is triggered by problem-situations, for example: "In order to better see small objects I need a magnifying glass. But when using a magnifier, small object images are sometimes seen upright and sometimes seen reversed!" Along the way, pupils' reasoning will converge to the idea: "The image of an object through a lens depends on the relative distances among object, lens, and observer". Associated learning model: EXPERIMENT Specific competencies: derived from the experiment model, in agreement with the following learning unit steps I. Evoking - Anticipation: Size of the problem, formulation of hypotheses and planning of experiment. II

  5. Cellular proliferation and regeneration following tissue damage. Progress report. [X radiation; rabbit lenses

    Energy Technology Data Exchange (ETDEWEB)

    Harding, C.V.

    1977-01-01

    Studies were conducted on the following research projects: effects of x radiation on rabbit lenses; DNA synthesis and mitosis in cultured lenses; serum dependency and actinomycin D sensitivity; changes in ultrastructure; injury-induced growth of vascular endothelium; corneal neovascularization following injury; and human cataractous lenses. (HLW)

  6. Gauge-invariant formalism of cosmological weak lensing

    Science.gov (United States)

    Yoo, Jaiyul; Grimm, Nastassia; Mitsou, Ermis; Amara, Adam; Refregier, Alexandre

    2018-04-01

    We present the gauge-invariant formalism of cosmological weak lensing, accounting for all the relativistic effects due to the scalar, vector, and tensor perturbations at the linear order. While the light propagation is fully described by the geodesic equation, the relation of the photon wavevector to the physical quantities requires the specification of the frames, where they are defined. By constructing the local tetrad bases at the observer and the source positions, we clarify the relation of the weak lensing observables such as the convergence, the shear, and the rotation to the physical size and shape defined in the source rest-frame and the observed angle and redshift measured in the observer rest-frame. Compared to the standard lensing formalism, additional relativistic effects contribute to all the lensing observables. We explicitly verify the gauge-invariance of the lensing observables and compare our results to previous work. In particular, we demonstrate that even in the presence of the vector and tensor perturbations, the physical rotation of the lensing observables vanishes at the linear order, while the tetrad basis rotates along the light propagation compared to a FRW coordinate. Though the latter is often used as a probe of primordial gravitational waves, the rotation of the tetrad basis is indeed not a physical observable. We further clarify its relation to the E-B decomposition in weak lensing. Our formalism provides a transparent and comprehensive perspective of cosmological weak lensing.

  7. Modelling the line-of-sight contribution in substructure lensing

    Science.gov (United States)

    Despali, Giulia; Vegetti, Simona; White, Simon D. M.; Giocoli, Carlo; van den Bosch, Frank C.

    2018-04-01

    We investigate how Einstein rings and magnified arcs are affected by small-mass dark-matter haloes placed along the line of sight to gravitational lens systems. By comparing the gravitational signature of line-of-sight haloes with that of substructures within the lensing galaxy, we derive a mass-redshift relation that allows us to rescale the detection threshold (i.e. lowest detectable mass) for substructures to a detection threshold for line-of-sight haloes at any redshift. We then quantify the line-of-sight contribution to the total number density of low-mass objects that can be detected through strong gravitational lensing. Finally, we assess the degeneracy between substructures and line-of-sight haloes of different mass and redshift to provide a statistical interpretation of current and future detections, with the aim of distinguishing between cold dark matter and warm dark matter. We find that line-of-sight haloes statistically dominate with respect to substructures, by an amount that strongly depends on the source and lens redshifts, and on the chosen dark-matter model. Substructures represent about 30 percent of the total number of perturbers for low lens and source redshifts (as for the SLACS lenses), but less than 10 per cent for high-redshift systems. We also find that for data with high enough signal-to-noise ratio and angular resolution, the non-linear effects arising from a double-lens-plane configuration are such that one is able to observationally recover the line-of-sight halo redshift with an absolute error precision of 0.15 at the 68 per cent confidence level.

  8. On the measurement of the Lense Thirring effect using the nodes of the LAGEOS satellites, in reply to “On the reliability of the so-far performed tests for measuring the Lense Thirring effect with the LAGEOS satellites” by L. Iorio

    Science.gov (United States)

    Ciufolini, I.; Pavlis, E.

    2005-08-01

    In this paper, we provide a detailed description of our recent analysis and determination of the frame-dragging effect obtained using the nodes of the satellites LAGEOS and LAGEOS 2, in reply to the paper "On the reliability of the so-far performed tests for measuring the Lense-Thirring effect with the LAGEOS satellites" by L. Iorio (doi: 10.1016/j.newast.2005.01.001). First, we discuss the impact of the J2n uncertainties on our measurement and we show that the corresponding error is of the order of 1% of frame-dragging only. We report the result of the orbital simulations and analyses obtained with and without J and with a J equal to its EIGEN-GRACE02S value plus 12 times its published error, i.e., a J equal to about 611% of the value adopted in EIGEN-GRACE02S, that is J=6.11×(-1.41×10-11)≃-8.61×10-11. In all these three cases, by also fitting the final combined residuals with a quadratic, we obtain the same value of the measured Lense-Thirring effect. This value differs by only 1% with respect to our recent measurement of the Lense-Thirring effect. Therefore, the error due to the uncertainties in the J2n in our measurement of the gravitomagnetic effect can at most reach 1%, in complete agreement with our previously published error budget. Our total error budget in the measurement of frame-dragging is about 5% of the Lense-Thirring effect, alternatively even by simply considering the published errors in the J2n and their recent determinations we get a total error budget of the order of 10%, in complete agreement with our previously published error budget. Furthermore, we explicitly give the results and plot of a simulation clearly showing that the claim of Iorio's paper that the J2n uncertainty may contribute to up a 45% error error in our measurement is clearly unsubstantiated. We then present a rigorous proof that any "imprint" or "memory" effect of the Lense-Thirring effect is completely negligible on the even zonal harmonics produced using the GRACE

  9. Gravitational lensing by a Horndeski black hole

    Energy Technology Data Exchange (ETDEWEB)

    Badia, Javier [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Eiroa, Ernesto F. [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2017-11-15

    In this article we study gravitational lensing by non-rotating and asymptotically flat black holes in Horndeski theory. By adopting the strong deflection limit, we calculate the deflection angle, from which we obtain the positions and the magnifications of the relativistic images. We compare our results with those corresponding to black holes in General Relativity. We analyze the astrophysical consequences in the case of the nearest supermassive black holes. (orig.)

  10. The effect of spectral property and intensity of light on natural refractive development and compensation to negative lenses in guinea pigs.

    Science.gov (United States)

    Li, Wentao; Lan, Weizhong; Yang, Shiqi; Liao, Yunru; Xu, Qinglin; Lin, Lixia; Yang, Zhikuan

    2014-10-02

    To investigate the effect of spectral composition and light intensity on refractive development in guinea pigs. One-week-old guinea pigs were randomly assigned to groups exposed to broad-spectrum Solux halogen light (BS) or spiked-spectrum fluorescent light (FL) at both high (Hi, 10,000 lux) and low (Lo, 500 lux) intensities under a 12:12 light/dark cycle. Half of the animals in each group were used as controls (n = 24, 20, 22, and 20, respectively), and half were fitted with binocular -4-diopter (D) lenses (L, lenses; n = 22, 20, 24, and 22, respectively). Refractive error, corneal curvature, and axial dimensions were determined by cycloplegic retinoscopy, photokeratometry, and A-scan ultrasonography, respectively. Guinea pigs exposed to FL and BS showed similar changes in refraction under both high (HiFL: 2.26 ± 0.55 D versus HiBS: 2.17 ± 0.65 D, P > 0.05)- and low-intensity lighting (LoFL: 1.39 ± 0.88 D versus LoBS: 1.40 ± 0.93 D, P > 0.05). This was also true for the groups wearing lenses (HiFL-L: -1.81 ± 0.73 D versus HiBS-L: -1.45 ± 0.99 D, P > 0.05; LoFL-L: -2.58 ± 0.65 D versus LoBS-L: -2.29 ± 0.50 D, P > 0.05). Nevertheless, animals under high-intensity lighting exhibited a significantly larger hyperopic shift compared with those under low-intensity lighting (HiFL versus LoFL: P guinea pigs, spectrally spiked light and broad-spectrum light have similar effects on natural refractive development and negative lens compensation. As found in other species, effects of light intensity on refractive development were also observed in guinea pigs in both illuminants. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  11. Analytically calculated post-Keplerian range and range-rate perturbations: the solar Lense-Thirring effect and BepiColombo

    Science.gov (United States)

    Iorio, Lorenzo

    2018-02-01

    We analytically calculate the time series for the perturbations Δ ρ \\left(t\\right), Δ \\dot{ρ }\\left(t\\right) induced by a general disturbing acceleration \\boldsymbol{A} on the mutual range ρ and range-rate \\dot{ρ} of two test particles A, B orbiting the same spinning body. We apply it to the general relativistic Lense-Thirring effect, due to the primary's spin \\boldsymbol{S}, and the classical perturbation arising from its quadrupole mass moment J2 for arbitrary orbital geometries and orientation of the source's symmetry axis \\boldsymbol{\\hat{S}}. The Earth-Mercury range and range-rate are nominally affected by the Sun's gravitomagnetic field to the 10 m, 10-3 cm s-1 level, respectively, during the extended phase (2026-2028) of the forthcoming BepiColombo mission to Mercury whose expected tracking accuracy is of the order of ≃ 0.1 m, 2 × 10-4 cm s-1. The competing signatures due to the solar quadrupole J_2^\\odot, if modelled at the σ _{J_2^\\odot }˜eq 10^{-9} level of the latest planetary ephemerides INPOP17a, are nearly 10 times smaller than the relativistic gravitomagnetic effects. The position and velocity vectors \\mathbf {r}, \\mathbf {v} of Mercury and Earth are changed by the solar Lense-Thirring effect by about 10 m, 1.5 m and 10-3 cm s-1, 10-5 cm s-1, respectively, over 2 yr; neglecting such shifts may have an impact on long-term integrations of the inner solar system dynamics over ˜Gyr timescales.

  12. Fitting gravitational lenses: truth or delusion

    Science.gov (United States)

    Evans, N. Wyn; Witt, Hans J.

    2003-11-01

    The observables in a strong gravitational lens are usually just the image positions and sometimes the flux ratios. We develop a new and simple algorithm which allows a set of models to be fitted exactly to the observations. Taking our cue from the strong body of evidence that early-type galaxies are close to isothermal, we assume that the lens is scale-free with a flat rotation curve. External shear can be easily included. Our algorithm allows full flexibility regarding the angular structure of the lensing potential. Importantly, all the free parameters enter linearly into the model and so the lens and flux ratio equations can always be solved by straightforward matrix inversion. The models are only restricted by the fact that the surface mass density must be positive. We use this new algorithm to examine some of the claims made for anomalous flux ratios. It has been argued that such anomalies betray the presence of substantial amounts of substructure in the lensing galaxy. We demonstrate by explicit construction that some of the lens systems for which substructure has been claimed can be well fitted by smooth lens models. This is especially the case when the systematic errors in the flux ratios (caused by microlensing or differential extinction) are taken into account. However, there is certainly one system (B1422+231) for which the existing smooth models are definitely inadequate and for which substructure may be implicated. Within a few tens of kpc of the lensing galaxy centre, dynamical friction and tidal disruption are known to be very efficient at dissolving any substructure. Very little substructure is projected within the Einstein radius. The numbers of strong lenses for which substructure is currently being claimed may be so large that this contradicts rather than supports cold dark matter theories.

  13. Additive manufacturing of tunable lenses

    Science.gov (United States)

    Schlichting, Katja; Novak, Tobias; Heinrich, Andreas

    2017-02-01

    Individual additive manufacturing of optical systems based on 3D Printing offers varied possibilities in design and usage. In addition to the additive manufacturing procedure, the usage of tunable lenses allows further advantages for intelligent optical systems. Our goal is to bring the advantages of additive manufacturing together with the huge potential of tunable lenses. We produced tunable lenses as a bundle without any further processing steps, like polishing. The lenses were designed and directly printed with a 3D Printer as a package. The design contains the membrane as an optical part as well as the mechanical parts of the lens, like the attachments for the sleeves which contain the oil. The dynamic optical lenses were filled with an oil. The focal length of the lenses changes due to a change of the radius of curvature. This change is caused by changing the pressure in the inside of the lens. In addition to that, we designed lenses with special structures to obtain different areas with an individual optical power. We want to discuss the huge potential of this technology for several applications. Further, an appropriate controlling system is needed. Wéll show the possibilities to control and regulate the optical power of the lenses. The lenses could be used for illumination tasks, and in the future, for individual measurement tasks. The main advantage is the individuality and the possibility to create an individual design which completely fulfills the requirements for any specific application.

  14. An Assessment of the Systematic Uncertainty in Present and Future Tests of the Lense-Thirring Effect with Satellite Laser Ranging

    Science.gov (United States)

    Iorio, Lorenzo

    2009-12-01

    We deal with the attempts to measure the Lense-Thirring effect with the Satellite Laser Ranging (SLR) technique applied to the existing LAGEOS and LAGEOS II terrestrial satellites and to the recently approved LARES spacecraft. According to general relativity, a central spinning body of mass M and angular momentum S like the Earth generates a gravitomagnetic field which induces small secular precessions of the orbit of a test particle geodesically moving around it. Extracting this signature from the data is a demanding task because of many classical orbital perturbations having the same pattern as the gravitomagnetic one, like those due to the centrifugal oblateness of the Earth which represents a major source of systematic bias. The first issue addressed here is: are the so far published evaluations of the systematic uncertainty induced by the bad knowledge of the even zonal harmonic coefficients J ℓ of the multipolar expansion of the Earth’s geopotential reliable and realistic? Our answer is negative. Indeed, if the differences Δ J ℓ among the even zonals estimated in different Earth’s gravity field global solutions from the dedicated GRACE mission are assumed for the uncertainties δ J ℓ instead of using their covariance sigmas σ_{J_{ell}} , it turns out that the systematic uncertainty δ μ in the Lense-Thirring test with the nodes Ω of LAGEOS and LAGEOS II may be up to 3 to 4 times larger than in the evaluations so far published (5-10%) based on the use of the sigmas of one model at a time separately. The second issue consists of the possibility of using a different approach in extracting the relativistic signature of interest from the LAGEOS-type data. The third issue is the possibility of reaching a realistic total accuracy of 1% with LAGEOS, LAGEOS II and LARES, which should be launched in November 2009 with a VEGA rocket. While LAGEOS and LAGEOS II fly at altitudes of about 6000 km, LARES will be likely placed at an altitude of 1450 km. Thus

  15. Lensing of 21-cm fluctuations by primordial gravitational waves.

    Science.gov (United States)

    Book, Laura; Kamionkowski, Marc; Schmidt, Fabian

    2012-05-25

    Weak-gravitational-lensing distortions to the intensity pattern of 21-cm radiation from the dark ages can be decomposed geometrically into curl and curl-free components. Lensing by primordial gravitational waves induces a curl component, while the contribution from lensing by density fluctuations is strongly suppressed. Angular fluctuations in the 21-cm background extend to very small angular scales, and measurements at different frequencies probe different shells in redshift space. There is thus a huge trove of information with which to reconstruct the curl component of the lensing field, allowing tensor-to-scalar ratios conceivably as small as r~10(-9)-far smaller than those currently accessible-to be probed.

  16. Interaction of intraocular lenses with fibronectin and human lens epithelial cells: Effect of chemical composition and aging.

    Science.gov (United States)

    Tortolano, Lionel; Serrano, Carole; Jubeli, Emile; Saunier, Johanna; Yagoubi, Najet

    2015-12-01

    The aim of this study is to investigate in vitro interactions between hydrophobic acrylate intraocular lenses (IOLs) and their biological environment. The influence of lens chemical composition and aging on fibronectin (FN) adsorption and on IOLs cytotoxicity on human lens epithelial cells was examined. Cytotoxicity of acrylate monomers used in IOLs manufacture was also investigated. Four different IOLs were included in the study: Acrysof(®), Tecnis(®), EnVista(®), and iSert(®). Implants were artificially aged in a xenon arc chamber to simulate 2 years of light exposure. Fibronectin adsorption on IOL surface was quantified using ELISA and correlated to surface roughness determined with AFM. Direct contact cytotoxicity was determined with the MTT assay and cell morphology was observed with light microscopy. Results showed that fibronectin adsorption did not differ significantly among IOLs, whatever their chemical composition. Moreover, aging conditions did not impact fibronectin adsorption. All IOLs were biocompatible even after applying 2-year aging conditions, with cell viability higher than 70%. Five acrylate monomers appeared to be toxic in the range of concentrations tested, but no monomer release from the IOLs could be detected during accelerated 2-year incubation with saline solution. This study did not reveal an influence of chemical composition and aging on protein adsorption and on biocompatibility. © 2015 Wiley Periodicals, Inc.

  17. Magnetic electron lenses

    CERN Document Server

    1982-01-01

    No single volume has been entirely devoted to the properties of magnetic lenses, so far as I am aware, although of course all the numerous textbooks on electron optics devote space to them. The absence of such a volume, bringing together in­ formation about the theory and practical design of these lenses, is surprising, for their introduction some fifty years ago has created an entirely new family of commercial instruments, ranging from the now traditional transmission electron microscope, through the reflection and transmission scanning microscopes, to co­ lumns for micromachining and microlithography, not to mention the host of experi­ mental devices not available commercially. It therefore seemed useful to prepare an account of the various aspects of mag­ netic lens studies. These divide naturally into the five chapters of this book: the theoretical background, in which the optical behaviour is described and formu­ lae given for the various aberration coefficients; numerical methods for calculat­ ing...

  18. Effect of strong electrolytes on edible oils part III: viscosity of canola ...

    African Journals Online (AJOL)

    Effect of strong electrolytes on the viscosity of canola oil in 1,4 dioxane was undertaken. The viscosity of oil in 1,4 dioxane was found to increase with the concentration of oil and decrease with rise in temperature. Strong electrolytes reduce the rate of flow of oil in 1,4 dioxane. It was noted that amongst these electrolytes, ...

  19. Anomalous Josephson effect in semiconductor nanowire with strong spin-orbit interaction and Zeeman effect

    Science.gov (United States)

    Yokoyama, Tomohiro; Eto, Mikio; Nazarov, Yuli

    2014-03-01

    We theoretically investigate the Josephson junction using quasi-one dimensional semiconductor nanowires with strong spin-orbit (SO) interaction, e.g., InSb. First, we examine a simple model using a single scatterer to describe the elastic scattering due to impurities and SO interaction in the normal region.[1] The Zeeman effect is taken into account by the spin-dependent phase shift of electron and hole through the system. The interplay between SO interaction and Zeeman effect results in a finite supercurrent even when the phase difference between two superconductors is zero. Moreover, the critical current depends on its current direction if more than one conduction channel is present in the nanowire. Next, we perform a numerical simulation by the tight-binding model for the nanowire to confirm our simple model. Then, we show that a spin-dependent Fermi velocity due to the SO interaction causes the anomalous Josephson effect.

  20. Planck 2013 results. XVII. Gravitational lensing by large-scale structure

    CERN Document Server

    Ade, P.A.R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Basak, S.; Battaner, E.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R.C.; Cardoso, J.F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, L.Y.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Dechelette, T.; Delabrouille, J.; Delouis, J.M.; Desert, F.X.; Dickinson, C.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Ensslin, T.A.; Eriksen, H.K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Heraud, Y.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Ho, S.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lahteenmaki, A.; Lamarre, J.M.; Lasenby, A.; Laureijs, R.J.; Lavabre, A.; Lawrence, C.R.; Leahy, J.P.; Leonardi, R.; Leon-Tavares, J.; Lesgourgues, J.; Lewis, A.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prezeau, G.; Prunet, S.; Puget, J.L.; Pullen, A.R.; Rachen, J.P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rubino-Martin, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Spencer, L.D.; Starck, J.L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; White, M.; White, S.D.M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-01-01

    On the arcminute angular scales probed by Planck, the CMB anisotropies are gently perturbed by gravitational lensing. Here we present a detailed study of this effect, detecting lensing independently in the 100, 143, and 217GHz frequency bands with an overall significance of greater than 25sigma. We use the temperature-gradient correlations induced by lensing to reconstruct a (noisy) map of the CMB lensing potential, which provides an integrated measure of the mass distribution back to the CMB last-scattering surface. Our lensing potential map is significantly correlated with other tracers of mass, a fact which we demonstrate using several representative tracers of large-scale structure. We estimate the power spectrum of the lensing potential, finding generally good agreement with expectations from the best-fitting LCDM model for the Planck temperature power spectrum, showing that this measurement at z=1100 correctly predicts the properties of the lower-redshift, later-time structures which source the lensing ...

  1. Adherence of cysts and trophozoites of Acanthamoeba to unworn rigid gas permeable and soft contact lenses.

    Science.gov (United States)

    Sharma, S; Ramachandran, L; Rao, G N

    1995-10-01

    Contact lens related Acanthamoeba keratitis has been more often associated with the use of soft contact lenses than with the use of rigid gas permeable (RGP) contact lenses. We studied the adherence of Acanthamoeba cysts and trophozoites to unworn RGP (silicone acrylate and fluoropolymer) and low and high water content soft contact lenses marketed in India. A human corneal isolate of Acanthamoeba polyphaga suspended in saline (1 x 10(5) amoebae/mL) was used. Lens segments were exposed to A. polyphaga cysts or trophozoites with or without shaking. After exposure for zero to 7 hours, lenses were either washed or not washed and the adherence was determined using light microscopy and a hemocytometer (per square millimeter of the lens). Both cysts and trophozoites immediately adhered to all four types of lenses. Adhesion increased with an increase in exposure time. The number of adherent cysts and trophozoites was higher (P = 0.043-0.0003) in the unwashed group of lenses at all exposure times for all lenses. Among washed groups, adherence was greatest with RGP silicone acrylate and high water content soft lenses. Trophozoites of Acanthamoeba showed greater adherence to RGP lenses, whereas cysts showed greater adherence to high water content soft lenses. Shaking did not have a significant effect on adherence. Adhesion of Acanthamoeba to contact lenses may play an important role in the pathogenesis of Acanthamoeba keratitis.

  2. Strong Effect of Azodye Layer Thickness on RM-Stabilized Photoalignment

    Science.gov (United States)

    2017-05-21

    Strong Effect of Azodye Layer Thickness on RM-Stabilized Photoalignment Colin McGinty*, Valerie Finnemeyer**, Robert Reich**, Harry Clark...vertical alignment on these substrates. For the thinner BY layers, we do not see this strong evidence of out of plane reorientation. The out of...In this report we show the surprising effect that thin azodye layers demonstrate improved stability over those that are thicker. Figure 6

  3. Astrophysical observations: lensing and eclipsing Einstein's theories.

    Science.gov (United States)

    Bennett, Charles L

    2005-02-11

    Albert Einstein postulated the equivalence of energy and mass, developed the theory of special relativity, explained the photoelectric effect, and described Brownian motion in five papers, all published in 1905, 100 years ago. With these papers, Einstein provided the framework for understanding modern astrophysical phenomena. Conversely, astrophysical observations provide one of the most effective means for testing Einstein's theories. Here, I review astrophysical advances precipitated by Einstein's insights, including gravitational redshifts, gravitational lensing, gravitational waves, the Lense-Thirring effect, and modern cosmology. A complete understanding of cosmology, from the earliest moments to the ultimate fate of the universe, will require developments in physics beyond Einstein, to a unified theory of gravity and quantum physics.

  4. Nontrivial effects of high-frequency excitation for strongly damped mechanical systems

    DEFF Research Database (Denmark)

    Fidlin, Alexander; Thomsen, Jon Juel

    Some nontrivial effects are investigated, which can occur if strongly damped mechanical systems are subjected to strong high-frequency (HF) excitation. The main result is a theoretical prediction, supported by numerical simulation, that for such systems the (quasi-)equilibrium states can change...... that can be substantial (depending on the strength of the HF excitation) for finite values of the damping. The analysis is focused on the differences between the classic results for weakly damped systems, and new effects for which the strong damping terms are responsible. The analysis is based...... on a slightly modified averaging technique, and includes an elementary example of an elliptically excited pendulum for illustration, alongside with a generalization to a broader class of strongly damped dynamical systems with HF excitation. As an application example, the nontrivial behavior of a classical...

  5. Nontrivial effects of high-frequency excitation for strongly damped mechanical systems

    DEFF Research Database (Denmark)

    Fidlin, Alexander; Thomsen, Jon Juel

    2008-01-01

    Some non-trivial effects are investigated, which can occur if strongly damped mechanical systems are subjected to strong high-frequency (HF) excitation. The main result is a theoretical prediction, supported by numerical simulation, that for such systems the (quasi-)equilibrium states can change...... that can be substantial depending on the strength of the HF excitation) for finite values of the damping. The analysis is focused on the differences between the classic results for weakly damped systems, and new effects for which the strong damping terms are responsible. The analysis is based on a slightly...... modified averaging technique, and includes an elementary example of an elliptically excited pendulum for illustration, alongside with a generalization to a broader class of strongly damped dynamical systems with HF excitation. As an application example, the nontrivial behavior of a classical optimally...

  6. <strong>Effectiveness of Orthoses and Foot Training in patients with Patellofemoral Pain and hyperpronationstrong>

    DEFF Research Database (Denmark)

    Mølgaard, Carsten; Kaalund, Søren; Christensen, Marianne

    of treatment with functional foot orthoses, exercises, or orthoses with exercises. The intrinsic pedal muscles play an important role in support of the medial longitudinal arch. (2) There are however very little information of the effect from specific foot exercise as an imperative part of exercise program...... adolescent females (3). Soft foot orhtoses in addition to an exercise program resulted in significantly greater improvements in pain than treatment with flat insoles and exercises over eight weeks. A study from 2004 by Wiener-Ogilvie & Jones (4) found however no difference in outcome between 8 weeks...... to PFPS patients. The purpose of this prospective single blinded randomised study was to determine the effectiveness of a standardized foot training program combined with foot orthoses in patients with patellofemoral pain. This treatment was additional to a regular conservative patellofemoral regime...

  7. The epidemiology of microbial keratitis with silicone hydrogel contact lenses.

    Science.gov (United States)

    Stapleton, Fiona; Keay, Lisa; Edwards, Katie; Holden, Brien

    2013-01-01

    It was widely anticipated that after the introduction of silicone hydrogel lenses, the risk of microbial keratitis would be lower than with hydrogel lenses because of the reduction in hypoxic effects on the corneal epithelium. Large-scale epidemiological studies have confirmed that the absolute and relative risk of microbial keratitis is unchanged with overnight use of silicone hydrogel materials. The key findings include the following: (1) The risk of infection with 30 nights of silicone hydrogel use is equivalent to 6 nights of hydrogel extended wear; (2) Occasional overnight lens use is associated with a greater risk than daily lens use; (3) The rate of vision loss due to corneal infection with silicone hydrogel contact lenses is similar to that seen in hydrogel lenses; (4) The spectrum of causative organisms is similar to that seen in hydrogel lenses, and the material type does not impact the corneal location of presumed microbial keratitis; and (5) Modifiable risk factors for infection include overnight lens use, the degree of exposure, failing to wash hands before lens handling, and storage case hygiene practice. The lack of change in the absolute risk of disease would suggest that exposure to large number of pathogenic organisms can overcome any advantages obtained from eliminating the hypoxic effects of contact lenses. Epidemiological studies remain important in the assessment of new materials and modalities. Consideration of an early adopter effect with studies involving new materials and modalities and further investigation of the impact of second-generation silicone hydrogel materials is warranted.

  8. Computing effective properties of nonlinear structures exposed to strong high-frequency loading at multiple frequencies

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2006-01-01

    Effects of strong high-frequency excitation at multiple frequencies (multi-HFE) are analyzed for a class of generally nonlinear systems. The effects are illustrated for a simple pendulum system with a vibrating support, and for a parametrically excited flexible beam. For the latter, theoretical...

  9. Effect of using prismatic eye lenses on the posture of patients with adolescent idiopathic scoliosis measured by 3-d motion analysis.

    Science.gov (United States)

    Wong, M S; Mak, A F T; Luk, K D K; Evans, J H; Brown, B

    2002-08-01

    This is a preliminary investigation to detect the body sway and postural changes of patients with AIS under different spatial images. Two pairs of low-power prismatic eye lenses (Fresnel prisms) with 5 dioptre and 10 dioptre were used. In the experiment, the apices of the prisms were orientated randomly at every 22.5 degrees from 0 degrees to 360 degrees to test changes. Four patients with mean age of 11 and Cobb's angle of 30 degrees were recruited and the results showed that the low-power prisms at specific orientations (157.5 degrees and 180 degrees) could cause positive postural changes (2.1 degrees-2.7 degrees reduction of angle of trunk mis-alignment) measured by 3-D motion analysis. This might be used for controlling their scoliotic curves by induced visual bio-feedback. Apart from this laboratory test, a longitudinal study is necessary to investigate the long-term effect of the prisms at different powers and orientations (under both static and dynamic situations) on the patient's posture, spinal muscular activities, vision, eye-hand coordination, psychological state and other daily activities before it becomes an alternative management of AIS.

  10. On an illusion of superluminal velocities produced by gravitational lenses

    International Nuclear Information System (INIS)

    Ingel, L.Kh.

    1981-01-01

    It is noted that gravitational lenses, by focusing the radiation of an object, increase the angle which it subtends. This in turn produces the illusion of an increase in velocities at right angles to the line of sight. Preliminary estimates are made which indicate a rather high probability of strong distortion of the observed velocities

  11. Using strong nonlinearity and high-frequency vibrations to control effective properties of discrete elastic waveguides

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov; Thomsen, Jon Juel; Snaeland, Sveinn Orri

    2008-01-01

    The aim of this article is to investigate how highfrequency (HF) excitation, combined with strong nonlinear elastic material behavior, influences the effective material or structural properties for low-frequency excitation and wave propagation. The HF effects are demonstrated on discrete linear...... spring-mass chains with non-linear inclusions. The presented analytical and numerical results suggest that the effective material properties can easily be altered by establishing finite amplitude HF standing waves in the non-linear regions of the chain....

  12. Effective hadronic lagrangian in the strong coupling expansion of lattice QCD with Susskind fermions

    International Nuclear Information System (INIS)

    Azakov, S.I.; Aliev, E.S.

    1987-12-01

    The effective hadronic action in lattice QCD with U(N) and SU(N) gauge groups and with Susskind fermions is constructed in the framework of the strong coupling approximation. For arbitrary finite (odd) N (in particular N=3) we find an effective potential, vacuum expectation value of the (χ-barχ) and an effective action for the physical meson field π(x). (author). 19 refs

  13. Lensing bias to CMB polarization measurements of compensated isocurvature perturbations

    Science.gov (United States)

    Heinrich, Chen

    2018-01-01

    Compensated isocurvature perturbations (CIPs) are opposite spatial fluctuations in the baryon and dark matter (DM) densities. They arise in the curvaton model and some models of baryogenesis. While the gravitational effects of baryon fluctuations are compensated by those of DM, leaving no observable impacts on the cosmic microwave background (CMB) at first order, they modulate the sound horizon at recombination, thereby correlating CMB anisotropies at different multipoles. As a result, CIPs can be reconstructed using quadratic estimators similarly to CMB detection of gravitational lensing. Because of these similarities, however, the CIP estimators are biased with lensing contributions that must be subtracted. These lensing contributions for CMB polarization measurement of CIPs are found to roughly triple the noise power of the total CIP estimator on large scales. In addition, the cross power with temperature and E -mode polarization are contaminated by lensing-ISW (integrated Sachs-Wolfe) correlations and reionization-lensing correlations respectively. For a cosmic-variance-limited temperature and polarization experiment measuring out to multipoles lmax=2500 , the lensing noise raises the detection threshold by a factor of 1.5, leaving a 2.7 σ detection possible for the maximal CIP signal in the curvaton model.

  14. Comparative Evaluation of Ultraviolet and Visible Light Transmittance through Prescriptive Ophthalmic Minus Lenses

    Directory of Open Access Journals (Sweden)

    Mohammadreza Nazari

    2014-06-01

    Full Text Available Background: Wearing spectacles is the most common approach in correcting the refractive errors worldwide. Due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. These lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission of ultraviolet rays. This study aims to compare the transmission of ultraviolet (A and B and visible rays through coated and uncoated prescriptive ophthalmic plastic lenses.Materials and Methods: In this study, 39 minus non-photochromic multi-coated white plastic single-vision lenses; 9 similar lenses but without any coatings were assessed by spectral transmittancemeter for evaluation of the transmission of visible and ultraviolet rays.Results: The transmission of visible light was 97.9%±1.07% for coated lenses and 93.5%±0.54% for lenses without coating. Ultraviolet-A transmission was 12.15%±8.02% for coated lenses compared to 66.27%±23.92% in lenses without coating. The transmission of ultraviolet-B rays was 1.21%±0.4% and 23.0%±15.97% for lenses with and without coatings, respectively.Conclusion: The transmission of visible light was significantly higher in multi-coated lenses compared to uncoated samples; whereas the transmissions of ultraviolet rays in multi-coated lenses were significantly lower than uncoated ones. Therefore, it is recommended that, except for particular cases, prescribed lenses be equipped with this multi-layer coating.

  15. Gravitational lensing of the SNLS supernovae

    International Nuclear Information System (INIS)

    Kronborg, T.

    2011-01-01

    Type Ia supernovae have become an essential tool of modern observational cosmology. By studying the distance-redshift relation of a large number of supernovae, the nature of dark energy can be unveiled. Distances to Type Ia SNe are however affected by gravitational lensing which can induce systematic effects in the measurement of cosmology. The majority of the supernovae is slightly de-magnified whereas a small fraction is significantly magnified due to the mass distribution along the line of sight. This causes naturally an additional dispersion in the observed magnitudes. There are two different ways to estimate the magnification of a supernova. A first method consists in comparing the supernova luminosity, which is measured to about 15% precision, to the mean SN luminosity at the same redshift. Another estimate can be obtained from predicting the magnification induced by the foreground matter density modeled from the measurements of the luminosity of the galaxies with an initial prior on the mass-luminosity relation of the galaxies. A correlation between these 2 estimates will make it possible to tune the initially used mass-luminosity relation resulting in an independent measurement of the dark matter clustering based on the luminosity of SNe Ia. Evidently, this measurement depends crucially on the detection of this correlation also referred to as the lensing signal. This thesis is dedicated to the measurement of the lensing signal in the SNLS 3-year sample. (author)

  16. Electron lenses for the large hadron collider

    CERN Document Server

    Stancari†, G; Bruce, R; Redaelli, S; Rossi, A; Salvachua Ferrando, B

    2014-01-01

    Electron lenses are pulsed, magnetically confined electron beamswhose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-bybunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beamcompensation, and for the demonstration of halo scrapingwith hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. A conceptual design was recently completed, and the project is moving towards a technical design in 2014–2015 for construction in 2015–2017, if needed, after resuming LHC operations and re-assessing collimation needs and requirements at 6.5 TeV. Because of the...

  17. Planning, Instruction, and Assessment: Effective Teaching Practices. James H. Stronge Research-to-Practice Series

    Science.gov (United States)

    Grant, Leslie W.; Hindman, Jennifer; Stronge, James H.

    2010-01-01

    This entry in the James H. Stronge Research-to-Practice Series focuses on specific strategies teachers can use to improve the quality of their instruction. Studies have shown teacher quality to be the top indicator of student achievement, with the effects of good teachers apparent even as students move on to successive grades. In this book, Grant,…

  18. Engineering the Dynamics of Effective Spin-Chain Models for Strongly Interacting Atomic Gases

    DEFF Research Database (Denmark)

    Volosniev, A. G.; Petrosyan, D.; Valiente, M.

    2015-01-01

    We consider a one-dimensional gas of cold atoms with strong contact interactions and construct an effective spin-chain Hamiltonian for a two-component system. The resulting Heisenberg spin model can be engineered by manipulating the shape of the external confining potential of the atomic gas. We...

  19. Effects of interaction imbalance in a strongly repulsive one-dimensional Bose gas

    DEFF Research Database (Denmark)

    Barfknecht, Rafael Emilio; Zinner, Nikolaj Thomas; Foerster, Angela

    2018-01-01

    We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calculate...

  20. Parity violation effects in the hydrogen atom in the field of a strong electromagnetic wave

    International Nuclear Information System (INIS)

    Labzovsky, L.N.; Mitrushchenkov, A.O.

    1989-01-01

    The parity violation effects in the hydrogen atom in a strong electromagnetic laser field are considered. It is shown that there is the possibility of hyperrate measurements of different constants of the weak interaction in the hydrogen magnetic resonance experiments. (orig.)

  1. Effects of interaction imbalance in a strongly repulsive one-dimensional Bose gas

    DEFF Research Database (Denmark)

    Barfknecht, Rafael Emilio; Zinner, Nikolaj Thomas; Foerster, Angela

    2018-01-01

    We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calcula...

  2. Non-Oberbeck-Boussinesq effects in strongly turbulent Rayleigh-Bénard convection

    NARCIS (Netherlands)

    Ahlers, Günter; Brown, Eric; Fontenele Araujo Junior, F.; Funfschilling, Denis; Grossmann, Siegfried; Lohse, Detlef

    2006-01-01

    Non-Oberbeck–Boussinesq (NOB) effects on the Nusselt number $Nu$ and Reynolds number $\\hbox{\\it Re}$ in strongly turbulent Rayleigh–Bénard (RB) convection in liquids were investigated both experimentally and theoretically. In the experiments the heat current, the temperature difference, and the

  3. DETECTION OF LENSING SUBSTRUCTURE USING ALMA OBSERVATIONS OF THE DUSTY GALAXY SDP.81

    Energy Technology Data Exchange (ETDEWEB)

    Hezaveh, Yashar D.; Mao, Yao-Yuan; Morningstar, Warren; Blandford, Roger D.; Levasseur, Laurence Perreault; Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Dalal, Neal; Wen, Di; Kemball, Athol; Vieira, Joaquin D. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana IL 61801 (United States); Marrone, Daniel P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Carlstrom, John E. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Fassnacht, Christopher D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Holder, Gilbert P. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Marshall, Philip J. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Particle Physics and Astrophysics, SLAC National Accelerator Laboratory, Menlo Park, CA 94305 (United States); Murray, Norman [CITA, University of Toronto, 60 St. George St., Toronto ON M5S 3H8 (Canada)

    2016-05-20

    We study the abundance of substructure in the matter density near galaxies using ALMA Science Verification observations of the strong lensing system SDP.81. We present a method to measure the abundance of subhalos around galaxies using interferometric observations of gravitational lenses. Using simulated ALMA observations we explore the effects of various systematics, including antenna phase errors and source priors, and show how such errors may be measured or marginalized. We apply our formalism to ALMA observations of SDP.81. We find evidence for the presence of a M = 10{sup 8.96±0.12} M {sub ⊙} subhalo near one of the images, with a significance of 6.9 σ in a joint fit to data from bands 6 and 7; the effect of the subhalo is also detected in both bands individually. We also derive constraints on the abundance of dark matter (DM) subhalos down to M ∼ 2 × 10{sup 7} M {sub ⊙}, pushing down to the mass regime of the smallest detected satellites in the Local Group, where there are significant discrepancies between the observed population of luminous galaxies and predicted DM subhalos. We find hints of additional substructure, warranting further study using the full SDP.81 data set (including, for example, the spectroscopic imaging of the lensed carbon monoxide emission). We compare the results of this search to the predictions of ΛCDM halos, and find that given current uncertainties in the host halo properties of SDP.81, our measurements of substructure are consistent with theoretical expectations. Observations of larger samples of gravitational lenses with ALMA should be able to improve the constraints on the abundance of galactic substructure.

  4. Scleral lenses: a literature review.

    Science.gov (United States)

    Schornack, Muriel M

    2015-01-01

    To present a comprehensive review of current and historical literature on scleral lenses. A comprehensive search of several databases from each database's earliest inception to May 23, 2014 was conducted by an experienced librarian with input from the author to locate articles related to scleral lens design, fabrication, prescription, and management. A total of 899 references were identified, 184 of which were directly related to scleral lenses. References of interest were organized by date, topic, and study design. Most of articles published before 1983 presented lens design and fabrication techniques or indications for scleral lens therapy. Case reviews published after 1983 identified major indications for scleral lenses (corneal ectasia, ocular surface disease, and refractive error) and visual and functional outcomes of scleral lens wear. Statistically significant improvements in visual acuity, vision-related quality of life, and ocular surface integrity were reported. Reviews of ocular and systemic conditions suggested that comprehensive management strategies for these conditions could include scleral lenses. Early work investigating scleral lens fitting characteristics, optical qualities, and potential physiological impact on anterior ocular structures have been published in the past 5 years. Indications for scleral lens wear are well-established. Developing areas of research on the physiologic impact of scleral lens wear on the ocular surface, the use of technology to improve scleral lens vision and fit, and the impact of these devices on the quality of life should further enhance our understanding of scleral lenses in the future.

  5. Constraints on small-scale cosmological fluctuations from SNe lensing dispersion

    International Nuclear Information System (INIS)

    Ben-Dayan, Ido; Takahashi, Ryuichi

    2015-04-01

    We provide predictions on small-scale cosmological density power spectrum from supernova lensing dispersion. Parameterizing the primordial power spectrum with running α and running of running β of the spectral index, we exclude large positive α and β parameters which induce too large lensing dispersions over current observational upper bound. We ran cosmological N-body simulations of collisionless dark matter particles to investigate non-linear evolution of the primordial power spectrum with positive running parameters. The initial small-scale enhancement of the power spectrum is largely erased when entering into the non-linear regime. For example, even if the linear power spectrum at k>10 hMpc -1 is enhanced by 1-2 orders of magnitude, the enhancement much decreases to a factor of 2-3 at late time (z≤1.5). Therefore, the lensing dispersion induced by the dark matter fluctuations weakly constrains the running parameters. When including baryon-cooling effects (which strongly enhance the small-scale clustering), the constraint is comparable or tighter than the PLANCK constraint, depending on the UV cut-off. Further investigations of the non-linear matter spectrum with baryonic processes is needed to reach a firm constraint.

  6. Heavy quark mass effects and improved tests of the flavor independence of strong interactions

    Energy Technology Data Exchange (ETDEWEB)

    Burrows, P.N. [Univ. of Oxford (United Kingdom); SLD Collaboration

    1998-08-01

    A review is given of latest results on tests of the flavor independence of strong interactions. Heavy quark mass effects are evident in the data and are now taken into account at next-to-leading order in QCD perturbation theory. The strong-coupling ratios {alpha}{sub s}{sup b}/{alpha}{sub s}{sup uds} and {alpha}{sub s}{sup c}/{alpha}{sub s}{sup uds} are found to be consistent with unity. Determinations of the b-quark mass m{sub b} (M{sub Z}) are discussed.

  7. Strong interaction effects in high-Z K sup minus atoms

    Energy Technology Data Exchange (ETDEWEB)

    Batty, C.J.; Eckhause, M.; Gall, K.P.; Guss, P.P.; Hertzog, D.W.; Kane, J.R.; Kunselman, A.R.; Miller, J.P.; O' Brien, F.; Phillips, W.C.; Powers, R.J.; Roberts, B.L.; Sutton, R.B.; Vulcan, W.F.; Welsh, R.E.; Whyley, R.J.; Winter, R.G. (Rutherford-Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom (GB) College of William and Mary, Williamsburg, Virginia 23185 Boston University, Boston, Massachusetts 02215 University of Wyoming, Laramie, Wyoming 82071 California Institute of Technology, Pasadena, California 91125 Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213)

    1989-11-01

    A systematic experimental study of strong interaction shifts, widths, and yields from high-{ital Z} kaonic atoms is reported. Strong interaction effects for the {ital K}{sup {minus}}(8{r arrow}7) transition were measured in U, Pb, and W, and the {ital K}{sup {minus}}(7{r arrow}6) transition in W was also observed. This is the first observation of two measurably broadened and shifted kaonic transitions in a single target and thus permitted the width of the upper state to be determined directly, rather than being inferred from yield data. The results are compared with optical-model calculations.

  8. Efficacy of progressive addition lenses in the treatment of ametropia after the single eye's IOL implantation.

    Science.gov (United States)

    Chen, Lin Xing; Zeng, Ying Yu; Zeng, Jun Wen; He, Ming Guang

    2012-09-01

    To investigate the efficacy of progressive addition lenses on the treatment of ametropia and loss of accomodation after the single eye's IOL implantation. Eighty four patients undergoing IOL implantation in single eyes were prescribed with progressive addition lenses for ametropia correction and regularly followed up to observe subsequent correction effect. Among these 84 patients, 72 could comfortably adapt to the use of progressive addition lenses to improve visual acuity and accomondation, while the remaining 12 patients failed to accomodate the usage of progressive addition lenses. Wearing progressive addition lenses acts as a relatively feasible approach to improve visual acuity and alleviate disorders of accomodation for patients who underwent IOL implantation in single eyes. The patients should be prescribed with progressive lenses under professional instructions and guidance.

  9. Auger effect in the presence of strong x-ray pulses

    International Nuclear Information System (INIS)

    Liu Jicai; Sun Yuping; Wang Chuankui; Aagren, Hans; Gel'mukhanov, Faris

    2010-01-01

    We study the role of propagation of strong x-ray free-electron laser pulses on the Auger effect. When the system is exposed to a strong x-ray pulse the stimulated emission starts to compete with the Auger decay. As an illustration we present numerical results for Ar gas with the frequency of the incident x-ray pulse tuned in the 2p 3/2 -4s resonance. It is shown that the pulse propagation is accompanied by two channels of amplified spontaneous emission, 4s-2p 3/2 and 3s-2p 3/2 , which reshape the pulse when the system is inverted. The population inversion is quenched for longer propagation distances where lasing without inversion enhances the Stokes component. The results of simulations show that the propagation of the strong x-ray pulses affect intensively the Auger branching ratio.

  10. Aspheric lenses for terahertz imaging.

    Science.gov (United States)

    Lo, Yat Hei; Leonhardt, Rainer

    2008-09-29

    We present novel designs for aspheric lenses used in terahertz (THz) imaging. As different surfaces result in different beam shaping properties and in different losses from reflection and absorption, the resultant imaging resolution (i.e. the focal spot size) depends critically on the design approach. We evaluate the different lens designs using Kirchhoff's scalar diffraction theory, and test the predictions experimentally. We also show that our lenses can achieve sub-wavelength resolution. While our lens designs are tested with THz radiation, the design considerations are applicable also to other regions of the electro-magnetic spectrum.

  11. Gravitational lensing by exotic objects

    Science.gov (United States)

    Asada, Hideki

    2017-11-01

    This paper reviews a phenomenological approach to the gravitational lensing by exotic objects such as the Ellis wormhole lens, where the exotic lens objects may follow a non-standard form of the equation of state or may obey a modified gravity theory. A gravitational lens model is proposed in the inverse powers of the distance, such that the Schwarzschild lens and exotic lenses can be described in a unified manner as a one parameter family. As observational implications, the magnification, shear, photo-centroid motion and time delay in this lens model are discussed.

  12. Influence of Tear Protein Deposition on the Oxygen Permeability of Soft Contact Lenses

    Directory of Open Access Journals (Sweden)

    Se Eun Lee

    2017-01-01

    Full Text Available Purpose. To investigate the effect of tear protein deposition on the change in oxygen permeability (Dk of soft contact lenses (SCL. Methods. Three hydrogel lenses (polymacon, nelfilcon A, and etafilcon A and two silicon hydrogel lenses (lotrafilcon A and balafilcon A were investigated. Etafilcon A lenses were incubated in artificial tear solution for 1, 6, 12, and 48 h, whereas the other SCL were incubated for 1, 3, 7, and 14 days. Oxygen permeability was measured using the polarographic method, and lenses were stacked in four layers to correct the boundary effect. Results. The Dk of all investigated SCL was decreased by the protein deposition. Silicone hydrogel lenses showed a smaller deposition of artificial tear proteins than conventional hydrogel lenses. However, their Dk was reduced twofold than those of 3 conventional hydrogel lenses when compared at the same level of protein deposition. Despite a large amount of total deposited protein in etafilcon A lenses, their Dk was more stable than other SCL. Conclusions. From the results, it was revealed that the Dk of SCL is different from the value provided by manufacturers because of the tear protein deposition on surface and/or in pore of SCL; however, the degree of Dk change in SCL was not simply correlated with the amount of tear protein deposition. Thus, it is considered that the correlation between tear protein deposition and properties of lens materials affects Dk change.

  13. Fluid Lensing and Applications to Remote Sensing of Aquatic Environments

    Science.gov (United States)

    Chirayath, Ved

    2017-01-01

    The use of fluid lensing technology on UAVs is presented as a novel means for 3D imaging of aquatic ecosystems from above the water's surface at the centimeter scale. Preliminary results are presented from airborne fluid lensing campaigns conducted over the coral reefs of Ofu Island, American Samoa (2013) and the stromatolite reefs of Shark Bay, Western Australia (2014), covering a combined area of 15km2. These reef ecosystems were revealed with centimetre-scale 2D resolution, and an accompanying 3D bathymetry model was derived using fluid lensing, Structure from Motion and UAV position data. Data products were validated from in-situ survey methods including underwater calibration targets, depth measurements and millimetre-scale high-dynamic range gigapixel photogrammetry. Fluid lensing is an experimental technology that uses water transmitting wavelengths to passively image underwater objects at high-resolution by exploiting time-varying optical lensing events caused by surface waves. Fluid lensing data are captured from low-altitude, cost-effective electric UAVs to achieve multispectral imagery and bathymetry models at the centimetre scale over regional areas. As a passive system, fluid lensing is presently limited by signal-to-noise ratio and water column inherent optical properties to approximately 10 m depth over visible wavelengths in clear waters. The datasets derived from fluid lensing present the first centimetre-scale images of a reef acquired from above the ocean surface, without wave distortion. The 3D multispectral data distinguish coral, fish and invertebrates in American Samoa, and reveal previously undocumented, morphologically distinct, stromatolite structures in Shark Bay. These findings suggest fluid lensing and multirotor electric drones represent a promising advance in the remote sensing of aquatic environments at the centimetre scale, or 'reef scale' relevant to the conservation of reef ecosystems. Pending further development and validation of

  14. Impact of surface roughness on the effective dielectric constants and subwavelength image resolution of metal-insulator stack lenses.

    Science.gov (United States)

    Shivanand; Ludwig, Alon; Webb, Kevin J

    2012-10-15

    The effective parallel and perpendicular dielectric constants for a multilayer metal–insulator stack are obtained from numerical simulations and compared with analytical homogenization results as a function of wavelength and number of periods. The influence of inevitable film surface roughness on the homogenized dielectric constants, determined from numerical scattered field calculations, is evaluated as a function of roughness. The impact of this roughness on resolution in a subwavelength imaging application gives smoothness guidelines for material deposition.

  15. Strong coupling electrostatics for randomly charged surfaces: antifragility and effective interactions.

    Science.gov (United States)

    Ghodrat, Malihe; Naji, Ali; Komaie-Moghaddam, Haniyeh; Podgornik, Rudolf

    2015-05-07

    We study the effective interaction mediated by strongly coupled Coulomb fluids between dielectric surfaces carrying quenched, random monopolar charges with equal mean and variance, both when the Coulomb fluid consists only of mobile multivalent counterions and when it consists of an asymmetric ionic mixture containing multivalent and monovalent (salt) ions in equilibrium with an aqueous bulk reservoir. We analyze the consequences that follow from the interplay between surface charge disorder, dielectric and salt image effects, and the strong electrostatic coupling that results from multivalent counterions on the distribution of these ions and the effective interaction pressure they mediate between the surfaces. In a dielectrically homogeneous system, we show that the multivalent counterions are attracted towards the surfaces with a singular, disorder-induced potential that diverges logarithmically on approach to the surfaces, creating a singular but integrable counterion density profile that exhibits an algebraic divergence at the surfaces with an exponent that depends on the surface charge (disorder) variance. This effect drives the system towards a state of lower thermal 'disorder', one that can be described by a renormalized temperature, exhibiting thus a remarkable antifragility. In the presence of an interfacial dielectric discontinuity, the singular behavior of counterion density at the surfaces is removed but multivalent counterions are still accumulated much more strongly close to randomly charged surfaces as compared with uniformly charged ones. The interaction pressure acting on the surfaces displays in general a highly non-monotonic behavior as a function of the inter-surface separation with a prominent regime of attraction at small to intermediate separations. This attraction is caused directly by the combined effects from charge disorder and strong coupling electrostatics of multivalent counterions, which dominate the surface-surface repulsion due to

  16. Empty creditors and strong shareholders: The real effects of credit risk trading. Second draft

    OpenAIRE

    Colonnello, Stefano; Efing, Matthias; Zucchi, Francesca

    2016-01-01

    Credit derivatives give creditors the possibility to transfer debt cash flow rights to other market participants while retaining control rights. We use the market for credit default swaps (CDSs) as a laboratory to show that the real effects of such debt unbundling crucially hinge on shareholder bargaining power. We find that creditors buy more CDS protection when facing strong shareholders to secure themselves a valuable outside option in distressed renegotiations. After the start of CDS trad...

  17. [Effects of strong reductive approach on remediation of degraded facility vegetable soil].

    Science.gov (United States)

    Zhu, Tong-Bin; Meng, Tian-Zhu; Zhang, Jin-Bo; Cai, Zu-Cong

    2013-09-01

    High application rate of chemical fertilizers and unreasonable rotation in facility vegetable cultivation can easily induce the occurrence of soil acidification, salinization, and serious soil-borne diseases, while to quickly and effectively remediate the degraded facility vegetable soil can considerably increase vegetable yield and farmers' income. In this paper, a degraded facility vegetable soil was amended with 0, 3.75, 7.50, and 11.3 t C x hm(-2) of air-dried alfalfa and flooded for 31 days to establish a strong reductive environment, with the variations of soil physical and chemical properties and the cucumber yield studied. Under the reductive condition, soil Eh dropped quickly below 0 mV, accumulated soil NO3(-) was effectively eliminated, soil pH was significantly raised, and soil EC was lowered, being more evident in higher alfalfa input treatments. After treated with the strong reductive approach, the cucumber yield in the facility vegetable field reached 53.3-57.9 t x hm(-2), being significantly higher than that in un-treated facility vegetable field in last growth season (10.8 t x hm(-2)). It was suggested that strong reductive approach could effectively remediate the degraded facility vegetable soil in a short term.

  18. Gravitational lensing effect and polarization of the cosmic microwave background in the PLANCK Experiment and post-planckian projects; Effet de lentilles gravitationnelles et polarisation du fond diffus cosmologique dans le cadre de l'experience PLANCK et de projets post-planckiens

    Energy Technology Data Exchange (ETDEWEB)

    Perotto, Laurence [Universite Paris 7 - Denis Diderot, UFR de Physique, 75205 Paris Cedex 13 (France)

    2006-01-15

    This thesis is motivated by the upcoming high-resolution, high-sensitivity microwave background experiments, which should be sensitive to the CMB polarization and lensing. The first chapter provides a review of the CMB polarization with emphasis on future related experiments. The PLANCK experiment is described in a second chapter, where I develop a fast simulation code of PLANCK time-ordered data optimized to ease elaboration and test of data analysis methods. The two last chapters deal with gravitational lensing of the cosmic background radiation. First, I evaluate the capability of the upcoming experiments mentioned above to measure the power spectrum of Large Scale Structure by means of the extraction of weak lensing. Then I derive their sensitivity to the total neutrino mass, using the suppression of power due to free-streaming of massive neutrinos. Finally, I develop a method to estimate the foreground effects in the gravitational lensing extraction process. This method uses the best linear estimator available in the literature and is validated by numerical simulations that include non-Gaussian CMB lensed maps and extra-galactic radio sources maps. I find that sources emission reduces the sensitivity of future experiments to the weak lensing and leads to an overestimate of the convergence power spectrum. (author)

  19. ECOGIG: Oil spill effects on deep-sea corals through the lenses of natural hydrocarbon seeps and long time series

    Science.gov (United States)

    Cordes, Erik E.; Auscavitch, Steven; Baums, Iliana B.; Fisher, Charles R.; Girard, Fanny; Gomez, Carlos; McClain-Counts, Jennifer P.; Mendlovitz, Howard P.; Saunders, Miles; Smith, Styles; Vohsen, Samuel; Weinheimer, Alaina

    2016-01-01

    The 2015 Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG) expedition was a continuation of a three-year partnership between our Gulf of Mexico Research Institute-funded research consortium and the Ocean Exploration Trust to study the effects of oil and dispersant on corals and closely related communities affected by the 2010 Deepwater Horizon oil spill (White et al., 2012, 2014; Hsing et al., 2013; Fisher et al., 2014a,b; Figure 1A– C). As part of our analysis, we explored a new site to the west of the Macondo well in lease block Mississippi Canyon (MC) 462 where we examined 50 new corals for impact from the spill (Figure 1D). A total of over 250 corals were re-imaged in 2015 for this ongoing time-series study. Another goal was to initiate a study to determine how proximity to natural seeps affects corals and infauna in these communities.

  20. Gravitational Lensing of Supernova Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Mena, Olga; /Fermilab /Rome U.; Mocioiu, Irina; /Penn State U.; Quigg, Chris; /Fermilab

    2006-10-01

    The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse.

  1. The Optical Gravitational Lensing Experiment

    Science.gov (United States)

    Udalski, A.; Szymanski, M.; Kaluzny, J.; Kubiak, M.; Mateo, Mario

    1992-01-01

    The technical features are described of the Optical Gravitational Lensing Experiment, which aims to detect a statistically significant number of microlensing events toward the Galactic bulge. Clusters of galaxies observed during the 1992 season are listed and discussed and the reduction methods are described. Future plans are addressed.

  2. Scientific visualization of gravitational lenses

    International Nuclear Information System (INIS)

    Magallon, M.

    1999-01-01

    Concepts related to gravitational lenses are discussed and applied to develop an interactive visualization tool that allow us to investigate them. Optimization strategies were performed to elaborate the tool. Some results obtained from the application of the tool are shown [es

  3. Optics Demonstrations Using Cylindrical Lenses

    Science.gov (United States)

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  4. Polarization optics of GRIN lenses

    Science.gov (United States)

    Camacho, Javier; Tentori, Diana

    2001-01-01

    In this paper we show that the matrix representation for a linear retarder, given by Jones calculus, can be successfully applied to describe the birefringence properties of GRIN lenses for meridional rays. The usefulness of this description is experimentally verified by comparing the output pattern of a GRIN lens obtained in a linear polariscope with the predicted conoscopic pattern.

  5. Weak lensing and dark energy

    International Nuclear Information System (INIS)

    Huterer, Dragan

    2002-01-01

    We study the power of upcoming weak lensing surveys to probe dark energy. Dark energy modifies the distance-redshift relation as well as the matter power spectrum, both of which affect the weak lensing convergence power spectrum. Some dark-energy models predict additional clustering on very large scales, but this probably cannot be detected by weak lensing alone due to cosmic variance. With reasonable prior information on other cosmological parameters, we find that a survey covering 1000 sq deg down to a limiting magnitude of R=27 can impose constraints comparable to those expected from upcoming type Ia supernova and number-count surveys. This result, however, is contingent on the control of both observational and theoretical systematics. Concentrating on the latter, we find that the nonlinear power spectrum of matter perturbations and the redshift distribution of source galaxies both need to be determined accurately in order for weak lensing to achieve its full potential. Finally, we discuss the sensitivity of the three-point statistics to dark energy

  6. Weak lensing and cosmological investigation

    CERN Document Server

    Acquaviva, V

    2005-01-01

    In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the cosmic microwave background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l approximately=1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended t...

  7. Strong Stability Preserving Explicit Runge--Kutta Methods of Maximal Effective Order

    KAUST Repository

    Hadjimichael, Yiannis

    2013-07-23

    We apply the concept of effective order to strong stability preserving (SSP) explicit Runge--Kutta methods. Relative to classical Runge--Kutta methods, methods with an effective order of accuracy are designed to satisfy a relaxed set of order conditions but yield higher order accuracy when composed with special starting and stopping methods. We show that this allows the construction of four-stage SSP methods with effective order four (such methods cannot have classical order four). However, we also prove that effective order five methods---like classical order five methods---require the use of nonpositive weights and so cannot be SSP. By numerical optimization, we construct explicit SSP Runge--Kutta methods up to effective order four and establish the optimality of many of them. Numerical experiments demonstrate the validity of these methods in practice.

  8. Using strong nonlinearity and high-frequency vibrations to control effective mechanical stiffness

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2008-01-01

    High-frequency excitation (HFE) can be used to change the effective stiffness of an elastic structure, and related quanti-ties such as resonance frequencies, wave speed, buckling loads, and equilibrium states. There are basically two ways to do this: By using parametrical HFE (with or without non...... the method of direct separation of motions with results of a modified multiple scales ap-proach, valid also for strong nonlinearity, the stiffening ef-fect is predicted for a generic 1-dof system, and results are tested against numerical simulation and ((it is planned)) laboratory experiments....

  9. Three-loop Standard Model effective potential at leading order in strong and top Yukawa couplings

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Stephen P. [Santa Barbara, KITP

    2014-01-08

    I find the three-loop contribution to the effective potential for the Standard Model Higgs field, in the approximation that the strong and top Yukawa couplings are large compared to all other couplings, using dimensional regularization with modified minimal subtraction. Checks follow from gauge invariance and renormalization group invariance. I also briefly comment on the special problems posed by Goldstone boson contributions to the effective potential, and on the numerical impact of the result on the relations between the Higgs vacuum expectation value, mass, and self-interaction coupling.

  10. Attosecond counter-rotating-wave effect in xenon driven by strong fields

    Science.gov (United States)

    Anand, M.; Pabst, Stefan; Kwon, Ojoon; Kim, Dong Eon

    2017-05-01

    We investigate the subfemtosecond dynamics of a highly excited xenon atom coherently driven by a strong control field at which the Rabi frequency of the system is comparable to the frequency of a driving laser. The widely used rotating-wave approximation breaks down at such fields, resulting in features such as the counter-rotating-wave (CRW) effect. We present a time-resolved observation of the CRW effect in the highly excited 4 d-1n p xenon using attosecond transient absorption spectroscopy. Time-dependent many-body theory confirms the observation and explains the various features of the absorption spectrum seen in experiment.

  11. Interaction effects in a microscopic quantum wire model with strong spin-orbit interaction

    Science.gov (United States)

    Winkler, G. W.; Ganahl, M.; Schuricht, D.; Evertz, H. G.; Andergassen, S.

    2017-06-01

    We investigate the effect of strong interactions on the spectral properties of quantum wires with strong Rashba spin-orbit (SO) interaction in a magnetic field, using a combination of matrix product state and bosonization techniques. Quantum wires with strong Rashba SO interaction and magnetic field exhibit a partial gap in one-half of the conducting modes. Such systems have attracted wide-spread experimental and theoretical attention due to their unusual physical properties, among which are spin-dependent transport, or a topological superconducting phase when under the proximity effect of an s-wave superconductor. As a microscopic model for the quantum wire we study an extended Hubbard model with SO interaction and Zeeman field. We obtain spin resolved spectral densities from the real-time evolution of excitations, and calculate the phase diagram. We find that interactions increase the pseudo gap at k = 0 and thus also enhance the Majorana-supporting phase and stabilize the helical spin order. Furthermore, we calculate the optical conductivity and compare it with the low energy spiral Luttinger liquid result, obtained from field theoretical calculations. With interactions, the optical conductivity is dominated by an excotic excitation of a bound soliton-antisoliton pair known as a breather state. We visualize the oscillating motion of the breather state, which could provide the route to their experimental detection in e.g. cold atom experiments.

  12. Charging-delay effect on longitudinal dust acoustic shock wave in strongly coupled dusty plasma

    International Nuclear Information System (INIS)

    Ghosh, Samiran; Gupta, M.R.

    2005-01-01

    Taking into account the charging-delay effect, the nonlinear propagation characteristics of longitudinal dust acoustic wave in strongly coupled collisional dusty plasma described by generalized hydrodynamic model have been investigated. In the 'hydrodynamic limit', a Korteweg-de Vries Burger (KdVB) equation with a damping term arising due to dust-neutral collision is derived in which the Burger term is proportional to the dissipation due to dust viscosity through dust-dust correlation and charging-delay-induced anomalous dissipation. On the other hand, in the 'kinetic limit', a KdVB equation with a damping term and a nonlocal nonlinear forcing term arising due to memory-dependent strong correlation effect of dust fluid is derived in which the Burger term depends only on the charging-delay-induced dissipation. Numerical solution of integrodifferential equations reveals that (i) dissipation due to dust viscosity and principally due to charging delay causes excitation of the longitudinal dust acoustic shock wave in strongly coupled dusty plasma and (ii) dust-neutral collision does not appear to play any direct role in shock formation. The condition for the generation of shock is also discussed briefly

  13. Challenges in inflationary magnetogenesis: Constraints from strong coupling, backreaction, and the Schwinger effect

    Science.gov (United States)

    Sharma, Ramkishor; Jagannathan, Sandhya; Seshadri, T. R.; Subramanian, Kandaswamy

    2017-10-01

    Models of inflationary magnetogenesis with a coupling to the electromagnetic action of the form f2Fμ νFμ ν , are known to suffer from several problems. These include the strong coupling problem, the backreaction problem and also strong constraints due to the Schwinger effect. We propose a model which resolves all these issues. In our model, the coupling function, f , grows during inflation and transits to a decaying phase post-inflation. This evolutionary behavior is chosen so as to avoid the problem of strong coupling. By assuming a suitable power-law form of the coupling function, we can also neglect backreaction effects during inflation. To avoid backreaction post-inflation, we find that the reheating temperature is restricted to be below ≈1.7 ×104 GeV . The magnetic energy spectrum is predicted to be nonhelical and generically blue. The estimated present day magnetic field strength and the corresponding coherence length taking reheating at the QCD epoch (150 MeV) are 1.4 ×10-12 G and 6.1 ×10-4 Mpc , respectively. This is obtained after taking account of nonlinear processing over and above the flux-freezing evolution after reheating. If we consider also the possibility of a nonhelical inverse transfer, as indicated in direct numerical simulations, the coherence length and the magnetic field strength are even larger. In all cases mentioned above, the magnetic fields generated in our models satisfy the γ -ray bound below a certain reheating temperature.

  14. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab; Seryi, Andrei; /SLAC; Solyak, Nikolai; /Fermilab; Sytnik, Veniamin; /Serpukhov, IHEP; Tiunov, Mikhail; /Novosibirsk, IYF; Tkachenko, Leonid; /Serpukhov, IHEP; Wildman, David; Wolff, Daniel; Zhang, Xiao-Long; /Fermilab

    2011-09-12

    Fermilab's Tevatron is currently the world's highest energy accelerator in which tightly focused beams of 980 GeV protons and antiprotons collide at two dedicated interaction points (IPs). Both beams share the same beam pipe and magnet aperture and, in order to avoid multiple detrimental head-on collisions, the beams are placed on separated orbits everywhere except the main IPs by using high-voltage (HV) electrostatic separators. The electromagnetic beam-beam interaction at the main IPs together with the long-range interactions between separated beams adversely affect the collider performance, reducing the luminosity integral per store (period of continuous collisions) by 10-30%. Tuning the collider operation for optimal performance becomes more and more cumbersome as the beam intensities and luminosity increase. The long-range effects which (besides being nonlinear) vary from bunch to bunch are particularly hard to mitigate. A comprehensive review of the beam-beam effects in the Tevatron Collider Run II can be found in Ref. [1]. The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  15. Extended Parrondo's game and Brownian ratchets: Strong and weak Parrondo effect

    Science.gov (United States)

    Wu, Degang; Szeto, Kwok Yip

    2014-02-01

    Inspired by the flashing ratchet, Parrondo's game presents an apparently paradoxical situation. Parrondo's game consists of two individual games, game A and game B. Game A is a slightly losing coin-tossing game. Game B has two coins, with an integer parameter M. If the current cumulative capital (in discrete unit) is a multiple of M, an unfavorable coin pb is used, otherwise a favorable pg coin is used. Paradoxically, a combination of game A and game B could lead to a winning game, which is the Parrondo effect. We extend the original Parrondo's game to include the possibility of M being either M1 or M2. Also, we distinguish between strong Parrondo effect, i.e., two losing games combine to form a winning game, and weak Parrondo effect, i.e., two games combine to form a better-performing game. We find that when M2 is not a multiple of M1, the combination of B (M1) and B (M2) has strong and weak Parrondo effect for some subsets in the parameter space (pb,pg), while there is neither strong nor weak effect when M2 is a multiple of M1. Furthermore, when M2 is not a multiple of M1, a stochastic mixture of game A may cancel the strong and weak Parrondo effect. Following a discretization scheme in the literature of Parrondo's game, we establish a link between our extended Parrondo's game with the analysis of discrete Brownian ratchet. We find a relation between the Parrondo effect of our extended model to the macroscopic bias in a discrete ratchet. The slope of a ratchet potential can be mapped to the fair game condition in the extended model, so that under some conditions, the macroscopic bias in a discrete ratchet can provide a good predictor for the game performance of the extended model. On the other hand, our extended model suggests a design of a ratchet in which the potential is a mixture of two periodic potentials.

  16. Strong coupling effects between a meta-atom and MIM nanocavity

    Directory of Open Access Journals (Sweden)

    San Chen

    2012-09-01

    Full Text Available In this paper, we investigate the strong coupling effects between a meta-atom and a metal-insulator-metal (MIM nanocavity. By changing the meta-atom sizes, we achieve the meta-atomic electric dipole, quadrupole or multipole interaction with the plasmonic nanocavity, in which characteristic anticrossing behaviors demonstrate the occurrence of the strong coupling. The various interactions present obviously different splitting values and behaviors of dependence on the meta-atomic position. The largest Rabi-type splittings, about 360.0 meV and 306.1 meV, have been obtained for electric dipole and quadrupole interaction, respectively. We attribute the large splitting to the highly-confined cavity mode and the large transition dipole of the meta-atom. Also the Rabi-type oscillation in time domain is given.

  17. Realization of effective super Tonks-Girardeau gases via strongly attractive one-dimensional Fermi gases

    International Nuclear Information System (INIS)

    Chen Shu; Yin Xiangguo; Guan Liming; Guan Xiwen; Batchelor, M. T.

    2010-01-01

    A significant feature of the one-dimensional super Tonks-Girardeau gas is its metastable gas-like state with a stronger Fermi-like pressure than for free fermions which prevents a collapse of atoms. This naturally suggests a way to search for such strongly correlated behavior in systems of interacting fermions in one dimension. We thus show that the strongly attractive Fermi gas without polarization can be effectively described by a super Tonks-Girardeau gas composed of bosonic Fermi pairs with attractive pair-pair interaction. A natural description of such super Tonks-Girardeau gases is provided by Haldane generalized exclusion statistics. In particular, they are equivalent to ideal particles obeying more exclusive statistics than Fermi-Dirac statistics.

  18. Effects of Strong Correlations on the Disorder-Induced Zero Bias Anomaly

    Science.gov (United States)

    Atkinson, William; Song, Yun; Bulut, Sinan; Wortis, Rachel

    2009-03-01

    In conventional metals and semiconductors, density of states anomalies result from the interplay between disorder and interactions. Motivated by a number of experiments that find zero bias anomalies (ZBA) in transition metal oxides, we have performed calculations to determine the effect of strong correlations on the ZBA in disordered interacting systems. We use a self-consistent mean-field theory that incorporates strong correlations and treats spatial fluctuations of the disorder potential exactly. We discuss both the Anderson-Hubbard model and the extended Anderson-Hubbard model. We find that, even for a zero-range interaction, nonlocal self-energy corrections lead to the formation of an Altshuler-Aronov-like ZBA. In the extended Anderson-Hubbard model, Efros-Shklovskii-like physics dominates at large disorder.

  19. Flat liquid crystal diffractive lenses with variable focus and magnification

    Science.gov (United States)

    Valley, Pouria

    Non-mechanical variable lenses are important for creating compact imaging devices. Various methods employing dielectrically actuated lenses, membrane lenses, and liquid crystal lenses were previously proposed [1-4]. In This dissertation the design, fabrication, and characterization of innovative flat tunable-focus liquid crystal diffractive lenses (LCDL) are presented. LCDL employ binary Fresnel zone electrodes fabricated on Indium-Tin-Oxide using conventional micro-photolithography. The light phase can be adjusted by varying the effective refractive index of a nematic liquid crystal sandwiched between the electrodes and a reference substrate. Using a proper voltage distribution across various electrodes the focal length can be changed between several discrete values. Electrodes are shunted such that the correct phase retardation step sequence is achieved. If the number of 2pi zone boundaries is increased by a factor of m the focal length is changed from f to f/m based on the digitized Fresnel zone equation: f = rm2/2mlambda, where r m is mth zone radius, and lambda is the wavelength. The chromatic aberration of the diffractive lens is addressed and corrected by adding a variable fluidic lens. These LCDL operate at very low voltage levels (+/-2.5V ac input), exhibit fast switching times (20-150 ms), can have large apertures (>10 mm), and small form factor, and are robust and insensitive to vibrations, gravity, and capillary effects that limit membrane and dielectrically actuated lenses. Several tests were performed on the LCDL including diffraction efficiency measurement, switching dynamics, and hybrid imaging with a refractive lens. Negative focal lengths are achieved by adjusting the voltages across electrodes. Using these lenses in combination, magnification can be changed and zoom lenses can be formed. These characteristics make LCDL a good candidate for a variety of applications including auto-focus and zoom lenses in compact imaging devices such as camera

  20. Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars

    DEFF Research Database (Denmark)

    Choi, J.-Y; Park, S.-Y; Han, C.

    2012-01-01

    -source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius...

  1. Effective action for superfluid Fermi systems in the strong-coupling limit

    International Nuclear Information System (INIS)

    Dupuis, N.

    2005-01-01

    We derive the low-energy effective action for three-dimensional superfluid Fermi systems in the strong-coupling limit, where superfluidity originates from Bose-Einstein condensation of composite bosons. Taking into account density and pairing fluctuations on the same footing, we show that the effective action involves only the fermion density ρ r and its conjugate variable, the phase θ r of the pairing order parameter Δ r . We recover the standard action of a Bose superfluid of density ρ r /2, where the bosons have a mass m B =2m and interact via a repulsive contact potential with amplitude g B =4πa B /m B ,a B =2a (a the s-wave scattering length associated to the fermion-fermion interaction in vacuum). For lattice models, the derivation of the effective action is based on the mapping of the attractive Hubbard model onto the Heisenberg model in a uniform magnetic field, and a coherent state path integral representation of the partition function. The effective description of the Fermi superfluid in the strong-coupling limit is a Bose-Hubbard model with an intersite hopping amplitude t B =J/2 and an on-site repulsive interaction U B =2Jz, where J=4t 2 /U (t and -U are the intersite hopping amplitude and the on-site attraction in the (fermionic) Hubbard model, z the number of nearest-neighbor sites)

  2. Effective action for superfluid Fermi systems in the strong-coupling limit

    Science.gov (United States)

    Dupuis, N.

    2005-07-01

    We derive the low-energy effective action for three-dimensional superfluid Fermi systems in the strong-coupling limit, where superfluidity originates from Bose-Einstein condensation of composite bosons. Taking into account density and pairing fluctuations on the same footing, we show that the effective action involves only the fermion density ρr and its conjugate variable, the phase θr of the pairing order parameter Δr . We recover the standard action of a Bose superfluid of density ρr/2 , where the bosons have a mass mB=2m and interact via a repulsive contact potential with amplitude gB=4πaB/mB,aB=2a ( a the s -wave scattering length associated to the fermion-fermion interaction in vacuum). For lattice models, the derivation of the effective action is based on the mapping of the attractive Hubbard model onto the Heisenberg model in a uniform magnetic field, and a coherent state path integral representation of the partition function. The effective description of the Fermi superfluid in the strong-coupling limit is a Bose-Hubbard model with an intersite hopping amplitude tB=J/2 and an on-site repulsive interaction UB=2Jz , where J=4t2/U ( t and -U are the intersite hopping amplitude and the on-site attraction in the (fermionic) Hubbard model, z the number of nearest-neighbor sites).

  3. Precision cluster mass determination from weak lensing

    Science.gov (United States)

    Mandelbaum, Rachel; Seljak, Uroš; Baldauf, Tobias; Smith, Robert E.

    2010-07-01

    Weak gravitational lensing has been used extensively in the past decade to constrain the masses of galaxy clusters, and is the most promising observational technique for providing the mass calibration necessary for precision cosmology with clusters. There are several challenges in estimating cluster masses, particularly (a) the sensitivity to astrophysical effects and observational systematics that modify the signal relative to the theoretical expectations, and (b) biases that can arise due to assumptions in the mass estimation method, such as the assumed radial profile of the cluster. All of these challenges are more problematic in the inner regions of the cluster, suggesting that their influence would ideally be suppressed for the purpose of mass estimation. However, at any given radius the differential surface density measured by lensing is sensitive to all mass within that radius, and the corrupted signal from the inner parts is spread out to all scales. We develop a new statistic Υ(RR0) that is ideal for estimation of cluster masses because it completely eliminates mass contributions below a chosen scale (which we suggest should be about 20 per cent of the virial radius), and thus reduces sensitivity to systematic and astrophysical effects. We use simulated and analytical profiles including shape noise to quantify systematic biases on the estimated masses for several standard methods of mass estimation, finding that these can lead to significant mass biases that range from 10 to over 50 per cent. The mass uncertainties when using the new statistic Υ(RR0) are reduced by up to a factor of 10 relative to the standard methods, while only moderately increasing the statistical errors. This new method of mass estimation will enable a higher level of precision in future science work with weak lensing mass estimates for galaxy clusters.

  4. Magnified Weak Lensing Cross Correlation Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    nights on 4-m class telescopes, which gives concrete evidence of strong community support for this project. The WLT technique is based on the dependence of the gravitational shear signal on the angular diameter distances between the observer, the lens, and the lensed galaxy to measure cosmological parameters. By taking the ratio of measured shears of galaxies with different redshifts around the same lens, one obtains a measurement of the ratios of the angular diameter distances involved. Making these observations over a large range of lenses and background galaxy redshifts will measure the history of the expansion rate of the universe. Because this is a purely geometric measurement, it is insensitive to any form of evolution of objects or the necessity to understand the physics in the early universe. Thus, WLT was identified by the Dark Energy Task Force as perhaps the best method to measure the evolution of DE. To date, however, the conjecture of the DETF has not been experimentally verified, but will be by the proposed project. The primary reason for the lack of tomography measurements is that one must have an exceptional data-set to attempt the measurement. One needs both extremely good seeing (or space observations) in order to minimize the point spread function smearing corrections on weak lensing shear measurements and deep, multi-color data, from B to z, to measure reliable photometric redshifts of the background galaxies being lensed (which are typically too faint to obtain spectroscopic redshifts). Because the entire process from multi-drizzling the HST images, and then creating shear maps, to gathering the necessary ground based observations, to generating photo-zs and then carrying out the tomography is a complicated task, until the creation of our team, nobody has taken the time to connect all the levels of expertise necessary to carry out this project based on HST archival data. Our data are being used in 2 Ph.D. theses. Kellen Murphy, at Ohio University, is

  5. Effects of strong radiation reaction and quantum-electrodynamics on relativistic transparency

    Science.gov (United States)

    Zhang, Peng; Thomas, A. G. R.; Ridgers, C. P.

    2013-10-01

    Relativistic transparency is the process that optically switches the overdense plasma from opaque to transparent and enables light propagation through the otherwise opaque plasma, when light of sufficient intensity drives the electrons in the plasma to near light speeds. We study the relativistic transparency in radiation dominant and strong quantum electrodynamic (QED) regime, for the interaction of high-intensity laser pulses with a thin foil solid target. We analytically study the simplified motion of an electron in a circularly polarized plane wave to understand the physics of the transmissivity and absorption in the presence of classical and quantum-corrected, semiclassical radiation-reaction forces and the trapping of particles in nodes of laser standing wave through radiative cooling. These arguments are supported by both one dimensional and two dimensional particle-in-cell calculations including strong field QED effects. Measurement of the transmission of these pulses would be experimentally feasible and a robust test of the strong field QED particle-in-cell framework.

  6. Drag Effect of Kompsat-1 During Strong Solar and Geomagnetic Activity

    Directory of Open Access Journals (Sweden)

    J. Park

    2007-06-01

    Full Text Available In this paper, we analyze the orbital variation of the KOrea Multi-Purpose SATellite-1(KOMPSAT-1 in a strong space environment due to satellite drag by solar and geomagnetic activities. The satellite drag usually occurs slowly, but becomes serious satellite drag when the space environment suddenly changes via strong solar activity like a big flare eruption or coronal mass ejections(CMEs. Especially, KOMPSAT-1 as a low earth orbit satellite has a distinct increase of the drag acceleration by the variations of atmospheric friction. We consider factors of solar activity to have serious effects on the satellite drag from two points of view. One is an effect of high energy radiation when the flare occurs in the Sun. This radiation heats and expands the upper atmosphere of the Earth as the number of neutral particles is suddenly increased. The other is an effect of Joule and precipitating particle heating caused by current of plasma and precipitation of particles during geomagnetic storms by CMEs. It also affects the density of neutral particles by heating the upper atmosphere. We investigate the satellite drag acceleration associated with the two factors for five events selected based on solar and geomagnetic data from 2001 to 2002. The major results can be summarized as follows. First, the drag acceleration started to increase with solar EUV radiation with the best cross-correlation (r = 0.92 for 1 day delayed F10.7. Second, the drag acceleration and Dst index have similar patterns when the geomagnetic storm is dominant and the drag acceleration abruptly increases during the strong geomagnetic storm. Third, the background variation of the drag accelerations is governed by the solar radiation, while their short term (less than a day variations is governed by geomagnetic storms.

  7. Poly-ϵ-caprolactone/chitosan nanoparticles provide strong adjuvant effect for hepatitis B antigen.

    Science.gov (United States)

    Jesus, Sandra; Soares, Edna; Borchard, Gerrit; Borges, Olga

    2017-10-01

    This work aims to investigate the adjuvant effect of poly-ϵ-caprolactone/chitosan nanoparticles (NPs) for hepatitis B surface antigen (HBsAg) and the plasmid DNA encoding HBsAg (pRC/CMV-HBs). Both antigens were adsorbed onto preformed NPs. Vaccination studies were performed in C57BL/6 mice. Transfection efficiency was investigated in A549 cell line. HBsAg-adsorbed NPs generated strong anti-HBsAg IgG titers, mainly of IgG1 isotype, and induced antigen-specific IFN-γ and IL-17 secretion by spleen cells. The addition of pRC/CMV-HBs to the HBsAg-adsorbed NPs inhibited IL-17 secretion but had minor effect on IFN-γ levels. Lastly, pRC/CMV-HBs-loaded NPs generated a weak serum antibody response. Poly-ϵ-caprolactone/chitosan NPs provide a strong humoral adjuvant effect for HBsAg and induce a Th1/Th17-mediated cellular immune responses worth explore for hepatitis B virus vaccination.

  8. Dispersion of Co/CNTs via strong electrostatic adsorption method: Thermal treatment effect

    Energy Technology Data Exchange (ETDEWEB)

    Akbarzadeh, Omid, E-mail: omid.akbarzadeh63@gmail.com; Abdullah, Bawadi, E-mail: bawadi-abdullah@petronas.com.my; Subbarao, Duvvuri, E-mail: duvvuri-subbarao@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Zabidi, Noor Asmawati Mohd, E-mail: noorasmawati-mzabidi@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    The effect of different thermal treatment temperature on the structure of multi-walled carbon nanotubes (MWCNTs) and Co particle dispersion on CNTs support is studied using Strong electrostatic adsorption (SEA) method. The samples tested by N{sub 2}-adsorption, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). N{sub 2}-adsorption results showed BET surface area increased using thermal treatment and TEM images showed that increasing the thermal treatment temperature lead to flaky CNTs and defects introduced on the outer surface and Co particle dispersion increased.

  9. Gain length fitting formula for free-electron lasers with strong space-charge effects

    Directory of Open Access Journals (Sweden)

    G. Marcus

    2011-08-01

    Full Text Available We present a power-fit formula, obtained from a variational analysis using three-dimensional free-electron laser theory, for the gain length of a high-gain free-electron laser’s fundamental mode in the presence of diffraction, uncorrelated energy spread, and longitudinal space-charge effects. The approach is inspired by the work of Xie [Nucl. Instrum. Methods Phys. Res., Sect. A 445, 59 (2000NIMAER0168-900210.1016/S0168-9002(0000114-5], and provides a useful shortcut for calculating the gain length of the fundamental Gaussian mode of a free-electron laser having strong space-charge effects in the 3D regime. The results derived from analytic theory are in good agreement with detailed numerical particle simulations that also include higher-order space-charge effects, supporting the assumptions made in the theoretical treatment and the variational solutions obtained in the single-mode limit.

  10. Contact Lenses for Keratoconus- Current Practice

    Science.gov (United States)

    Moschos, Marilita M.; Nitoda, Eirini; Georgoudis, Panagiotis; Balidis, Miltos; Karageorgiadis, Eleftherios; Kozeis, Nikos

    2017-01-01

    Background: Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs). Objective: To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs. Method: Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling. Result: The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis. Conclusion: CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is

  11. Gravitational lensing in a cold dark matter universe

    Science.gov (United States)

    Narayan, Ramesh; White, Simon D. M.

    1988-01-01

    Gravitational lensing due to mass condensations in a biased cold dark matter (CDM) universe is investigated using the Press-Schechter (1974) theory with density fluctuation amplitudes taken from previous N-body work. Under the critical assumption that CDM haloes have small core radii, a distribution of image angular separations for high-z lensed quasars with a peak at about 1 arcsec and a half-width of a factor of about 10. Allowing for selection effects at small angular separations, this is in good agreement with the observed separations. The estimated frequency of lensing is somewhat lower than that observed, but the discrepancy can be removed by invoking amplification bias and by making a small upward adjustment to the density fluctuation amplitudes assumed in the CDM model.

  12. STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS

    International Nuclear Information System (INIS)

    Wang Yan; Li Xiangdong

    2012-01-01

    If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.

  13. Gravitational Lensing in the metric theory proposed by Sobouti

    Science.gov (United States)

    Bernal, Tula; Mendoza, Sergio

    2008-12-01

    Recently, Y. Sobouti (2007) has provided a metric theory f(R) that can account for certain dynamical anomalies observed in spiral galaxies. Mendoza & Rosas-Guevara (2007) have shown that in this theory there is an extra-bending as compared to standard general relativity. In the present work we have developed in more specific detail this additional lensing effect and we have made evaluations of the α parameter used in the model adjusting the theory to observations in X-rays of 13 clusters of galaxies with gravitational lensing ([6]).

  14. Probing dark energy with lensing magnification in photometric surveys.

    Science.gov (United States)

    Schneider, Michael D

    2014-02-14

    I present an estimator for the angular cross correlation of two tracers of the cosmological large-scale structure that utilizes redshift information to isolate separate physical contributions. The estimator is derived by solving the Limber equation for a reweighting of the foreground tracer that nulls either clustering or lensing contributions to the cross correlation function. Applied to future photometric surveys, the estimator can enhance the measurement of gravitational lensing magnification effects to provide a competitive independent constraint on the dark energy equation of state.

  15. Non trivial effect of strong high-frequency excitation on a nonlinear controlled system

    DEFF Research Database (Denmark)

    Fidlin, A.; Thomsen, Jon Juel

    2004-01-01

    due to control is usually high compared to uncontrolled systems. A standard optimal controller for a standard nonlinear system (a movable cart used to balance a pendulum vertically) is shown to exhibit pronounced bias error in presence of HF-excitation. The bias increases with increased excitation......Nontrivial effects of high-frequency excitation on mechanical uncontrolled systems have been investigated intensively in the last decade. Some of these effects are usually used in controlled systems in form of dither to smoothen out undesired friction and hysteresis. However the level of damping...... intensity, but it also increases with the increased control power. Analytic prediction for the bias shows, the interaction between fast excitation and strong damping terms in the control system to be the cause of the permanent control error. A "slow observer" ignoring fast motions is shown...

  16. Trapped in the extinction vortex? Strong genetic effects in a declining vertebrate population

    Directory of Open Access Journals (Sweden)

    Larsson Mikael

    2010-02-01

    Full Text Available Abstract Background Inbreeding and loss of genetic diversity are expected to increase the extinction risk of small populations, but detailed tests in natural populations are scarce. We combine long-term population and fitness data with those from two types of molecular markers to examine the role of genetic effects in a declining metapopulation of southern dunlins Calidris alpina schinzii, an endangered shorebird. Results The decline is associated with increased pairings between related individuals, including close inbreeding (as revealed by both field observations of parentage and molecular markers. Furthermore, reduced genetic diversity seems to affect individual fitness at several life stages. Higher genetic similarity between mates correlates negatively with the pair's hatching success. Moreover, offspring produced by related parents are more homozygous and suffer from increased mortality during embryonic development and possibly also after hatching. Conclusions Our results demonstrate strong genetic effects in a rapidly declining population, emphasizing the importance of genetic factors for the persistence of small populations.

  17. Strong matrix effect in low-energy He+ ion scattering from carbon

    International Nuclear Information System (INIS)

    Mikhailov, S.N.; Van den Oetelaar, L.C.A.; Brongersma, H.H.

    1994-01-01

    In low-energy ion scattering the contribution of neutralization processes to the scattered ion yield is very important in quantification. Neutralization of low-energy (1-3.5 keV) He + ions by carbon is found to be much stronger for graphitic than for carbidic carbon. The ion fraction for graphitic carbon for 2.5 keV 3 He + scattering over 136 is about 60 times lower than that for carbidic carbon. For the 4 He + isotope the effect is even larger. Such a strong matrix effect for one element has not been measured before in low-energy (1-3.5 keV) inert-gas ion scattering. The neutralization behaviour is discussed in terms of a special quasi-resonant neutralization process for graphite. ((orig.))

  18. Strongly correlated Fermi-systems: Non-Fermi liquid behavior, quasiparticle effective mass and their interplay

    Energy Technology Data Exchange (ETDEWEB)

    Shaginyan, V.R. [Petersburg Nuclear Physics Institute, RAS, Gatchina 188300 (Russian Federation); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)], E-mail: vrshag@thd.pnpi.spb.ru; Amusia, M.Ya. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Popov, K.G. [Komi Science Center, Ural Division, RAS, Syktyvkar 167982 (Russian Federation)

    2009-06-15

    Basing on the density functional theory of fermion condensation, we analyze the non-Fermi liquid behavior of strongly correlated Fermi-systems such as heavy-fermion metals. When deriving equations for the effective mass of quasiparticles, we consider solids with a lattice and homogeneous systems. We show that the low-temperature thermodynamic and transport properties are formed by quasiparticles, while the dependence of the effective mass on temperature, number density, magnetic fields, etc., gives rise to the non-Fermi liquid behavior. Our theoretical study of the heat capacity, magnetization, energy scales, the longitudinal magnetoresistance and magnetic entropy are in good agreement with the remarkable recent facts collected on the heavy-fermion metal YbRh{sub 2}Si{sub 2}.

  19. Strongly correlated Fermi-systems: Non-Fermi liquid behavior, quasiparticle effective mass and their interplay

    International Nuclear Information System (INIS)

    Shaginyan, V.R.; Amusia, M.Ya.; Popov, K.G.

    2009-01-01

    Basing on the density functional theory of fermion condensation, we analyze the non-Fermi liquid behavior of strongly correlated Fermi-systems such as heavy-fermion metals. When deriving equations for the effective mass of quasiparticles, we consider solids with a lattice and homogeneous systems. We show that the low-temperature thermodynamic and transport properties are formed by quasiparticles, while the dependence of the effective mass on temperature, number density, magnetic fields, etc., gives rise to the non-Fermi liquid behavior. Our theoretical study of the heat capacity, magnetization, energy scales, the longitudinal magnetoresistance and magnetic entropy are in good agreement with the remarkable recent facts collected on the heavy-fermion metal YbRh 2 Si 2 .

  20. A system of catoptric lenses

    International Nuclear Information System (INIS)

    McFarland, P.J.; Rambauske, W.R.

    1973-01-01

    Description is given of a system of catoptric lenses for combining energies provided by a certain number of sources, e.g. optical energies provided by a certain number of lasers. This system comprises sets of mirrors the reflecting surfaces of which have their focuses spaced from a common axis. The mirrors of all these sets are arranged on a common frame, which makes aperture-locking impossible. This can be applied to thermonuclear fusion [fr

  1. Bactericidal Effect of Strong Acid Electrolyzed Water against Flow Enterococcus faecalis Biofilms.

    Science.gov (United States)

    Cheng, Xiaogang; Tian, Yu; Zhao, Chunmiao; Qu, Tiejun; Ma, Chi; Liu, Xiaohua; Yu, Qing

    2016-07-01

    This study evaluated the bactericidal effect of strong acid electrolyzed water (SAEW) against flow Enterococcus faecalis biofilm and its potential application as a root canal irrigant. Flow E. faecalis biofilms were generated under a constant shear flow in a microfluidic system. For comparison, static E. faecalis biofilms were generated under a static condition on coverslip surfaces. Both the flow and static E. faecalis biofilms were treated with SAEW. Sodium hypochlorite (NaOCl, 5.25%) and normal saline (0.9%) were included as the controls. Bacterial reductions were evaluated using confocal laser scanning microscopy and the cell count method. Morphological changes of bacterial cells were observed using scanning electron microscopy. The confocal laser scanning microscopic and cell count results showed that SAEW had a bactericidal effect similar to that of 5.25% NaOCl against both the flow and static E. faecalis biofilms. The scanning electron microscopic results showed that smooth, consecutive, and bright bacteria surfaces became rough, shrunken, and even lysed after treated with SAEW, similar to those in the NaOCl group. SAEW had an effective bactericidal effect against both the flow and static E. faecalis biofilms, and it might be qualified as a root canal irrigant for effective root canal disinfection. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Long-term effects of the strong African American families program on youths' alcohol use.

    Science.gov (United States)

    Brody, Gene H; Chen, Yi-Fu; Kogan, Steven M; Murry, Velma McBride; Brown, Anita C

    2010-04-01

    This report extends earlier accounts by addressing the effects of the Strong African American Families (SAAF) program across 65 months. Two hypotheses were tested: (a) Rural African American youths randomly assigned to participate in SAAF would demonstrate lower rates of alcohol use than would control youths more than 5 years later, and (b) SAAF's effects on deterring the onset of alcohol use in early adolescence would carry forward to mediate the program's long-term effects. African American youths in rural Georgia (mean age at pretest = 10.8 years) were assigned randomly to the SAAF group (n = 369) or to a control group (n = 298). Past-month alcohol use was assessed at pretest and at 9, 18, 29, 53, and 65 months after pretest. SAAF participants increased their alcohol use at a slower rate than did adolescents in the control condition across the follow-up assessments. At the 65-month assessment, SAAF participants reported having drunk alcohol half as often as did youths in the control group. Consistent with the second hypothesis, SAAF's effects on deterring initiation carried forward to account for its effects on alcohol use across time. Training in protective parenting processes and self-regulatory skills during preadolescence may contribute to a self-sustaining trajectory of disinterest in and avoidance of alcohol use during adolescence when peers begin to model and sanction it. (c) 2010 APA, all rights reserved

  3. Fitness is strongly influenced by rare mutations of large effect in a microbial mutation accumulation experiment.

    Science.gov (United States)

    Heilbron, Karl; Toll-Riera, Macarena; Kojadinovic, Mila; MacLean, R Craig

    2014-07-01

    Our understanding of the evolutionary consequences of mutation relies heavily on estimates of the rate and fitness effect of spontaneous mutations generated by mutation accumulation (MA) experiments. We performed a classic MA experiment in which frequent sampling of MA lines was combined with whole genome resequencing to develop a high-resolution picture of the effect of spontaneous mutations in a hypermutator (ΔmutS) strain of the bacterium Pseudomonas aeruginosa. After ∼644 generations of mutation accumulation, MA lines had accumulated an average of 118 mutations, and we found that average fitness across all lines decayed linearly over time. Detailed analyses of the dynamics of fitness change in individual lines revealed that a large fraction of the total decay in fitness (42.3%) was attributable to the fixation of rare, highly deleterious mutations (comprising only 0.5% of fixed mutations). Furthermore, we found that at least 0.64% of mutations were beneficial and probably fixed due to positive selection. The majority of mutations that fixed (82.4%) were base substitutions and we failed to find any signatures of selection on nonsynonymous or intergenic mutations. Short indels made up a much smaller fraction of the mutations that were fixed (17.4%), but we found evidence of strong selection against indels that caused frameshift mutations in coding regions. These results help to quantify the amount of natural selection present in microbial MA experiments and demonstrate that changes in fitness are strongly influenced by rare mutations of large effect. Copyright © 2014 by the Genetics Society of America.

  4. Strong isotope effects on melting dynamics and ice crystallisation processes in cryo vitrification solutions.

    Directory of Open Access Journals (Sweden)

    Oleg Kirichek

    Full Text Available The nucleation and growth of crystalline ice during cooling, and further crystallization processes during re-warming are considered to be key processes determining the success of low temperature storage of biological objects, as used in medical, agricultural and nature conservation applications. To avoid these problems a method, termed vitrification, is being developed to inhibit ice formation by use of high concentration of cryoprotectants and ultra-rapid cooling, but this is only successful across a limited number of biological objects and in small volume applications. This study explores physical processes of ice crystal formation in a model cryoprotective solution used previously in trials on vitrification of complex biological systems, to improve our understanding of the process and identify limiting biophysical factors. Here we present results of neutron scattering experiments which show that even if ice crystal formation has been suppressed during quench cooling, the water molecules, mobilised during warming, can crystallise as detectable ice. The crystallisation happens right after melting of the glass phase formed during quench cooling, whilst the sample is still transiting deep cryogenic temperatures. We also observe strong water isotope effects on ice crystallisation processes in the cryoprotectant mixture. In the neutron scattering experiment with a fully protiated water component, we observe ready crystallisation occurring just after the glass melting transition. On the contrary with a fully deuteriated water component, the process of crystallisation is either completely or substantially supressed. This behaviour might be explained by nuclear quantum effects in water. The strong isotope effect, observed here, may play an important role in development of new cryopreservation strategies.

  5. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, D.; Omori, Y.; Benoit-Lévy, A.; Cawthon, R.; Chang, C.; Larsen, P.; Amara, A.; Bacon, D.; Crawford, T. M.; Dodelson, S.; Fosalba, P.; Giannantonio, T.; Holder, G.; Jain, B.; Kacprzak, T.; Lahav, O.; MacCrann, N.; Nicola, A.; Refregier, A.; Sheldon, E.; Story, K. T.; Troxel, M. A.; Vieira, J. D.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Becker, M. R.; Benson, B. A.; Bernstein, G. M.; Bernstein, R. A.; Bleem, L. E.; Bonnett, C.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carlstrom, J. E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reichardt, C. L.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Simard, G.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Wechsler, R. H.; Weller, J.

    2016-03-10

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg(2) of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of z(med) similar to 0.7, while the CMB lensing kernel is broad and peaks at z similar to 2. The resulting cross-correlation is maximally sensitive to mass fluctuations at z similar to 0.44. Assuming the Planck 2015 best-fitting cosmology, the amplitude of the DESxSPT cross-power is found to be A(SPT) = 0.88 +/- 0.30 and that from DESxPlanck to be A(Planck) = 0.86 +/- 0.39, where A = 1 corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of 2.9 sigma and 2.2 sigma, respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photo-z uncertainty and CMB lensing systematics. We calculate a value of A = 1.08 +/- 0.36 for DESxSPT when we correct the observations with a simple intrinsic alignment model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation. We provide forecasts for the expected signal-to-noise ratio of the combination of the five-year DES survey and SPT-3G.

  6. Effect of Floodplain Inundation on River Pollution in Taiwan's Strong Monsoonal Climate

    Science.gov (United States)

    Hester, E. T.; Lin, A. Y. C.

    2017-12-01

    River-floodplain interaction provides important benefits such as flood mitigation, provision of ecological habitat, and improved water quality. Human actions have historically reduced such interaction and associated benefits by diking, floodplain fill, and river regulation. In response, floodplain restoration has become popular in North America and Europe, but is less practiced in Asia. In Taiwan, unusually strong monsoons and steep terrain alter floodplain dynamics relative to elsewhere around the world, and provide a unique environment for floodplain management. We used numerical models of flow, transport, and reaction in river channels and floodplains to quantify the effect of river-floodplain interaction on water quality in Taiwan's strong monsoon and high topographic relief. We conducted sensitivity analyses of parameters such as river slope, monsoon severity, reservoir operation mode, degree of floodplain reconnection, contaminant reaction rate, and contaminant reaction type on floodplain connectivity and contaminant mitigation. We found significant differences in floodplain hydraulics and residence times in Taiwan's steep monsoonal environment relative to the shallower non-monsoonal environment typical of the eastern USA, with significant implications for water quality. For example, greater flashiness of floodplain inundation in Taiwan provides greater challenges for reconnecting sufficient floodplain volume to handle monsoonal runoff. Yet longer periods when floodplains are reliably dry means that such lands may have greater value for seasonal use such as parks or agriculture. The potential for floodplain restoration in Taiwan is thus significant, but qualitatively different than in the eastern USA.

  7. Mental health care and average happiness: strong effect in developed nations.

    Science.gov (United States)

    Touburg, Giorgio; Veenhoven, Ruut

    2015-07-01

    Mental disorder is a main cause of unhappiness in modern society and investment in mental health care is therefore likely to add to average happiness. This prediction was checked in a comparison of 143 nations around 2005. Absolute investment in mental health care was measured using the per capita number of psychiatrists and psychologists working in mental health care. Relative investment was measured using the share of mental health care in the total health budget. Average happiness in nations was measured with responses to survey questions about life-satisfaction. Average happiness appeared to be higher in countries that invest more in mental health care, both absolutely and relative to investment in somatic medicine. A data split by level of development shows that this difference exists only among developed nations. Among these nations the link between mental health care and happiness is quite strong, both in an absolute sense and compared to other known societal determinants of happiness. The correlation between happiness and share of mental health care in the total health budget is twice as strong as the correlation between happiness and size of the health budget. A causal effect is likely, but cannot be proved in this cross-sectional analysis.

  8. 30 CFR 18.30 - Windows and lenses.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed in...

  9. Optical quality and vision with iris-coloring soft contact lenses.

    Science.gov (United States)

    Ortiz, Carolina; Jiménez, Raimundo

    2014-05-01

    To study the influence of iris-coloring soft contact lenses, designed for changing apparent iris color, on optical quality and vision. Eighty subjects were included in this study. All participants were classified as emmetropic, with monocular best-corrected visual acuity of 20/20 or better. For 40 subjects, we measured the optical quality (aberrations, the Strehl ratio, and the objective scattering index) and visual performance before and after wearing the cosmetic soft contact lenses. We also measured the optical quality and visual performance for the other 40 subjects but with a different kind of lens (fantasy soft contact lenses). Iris-coloring soft contact lenses significantly increased coma-like and total higher-order aberrations and objective scattering index (p Iris-coloring soft contact lenses deteriorate the optical quality and worsen the contrast sensitivity function. Iris-coloring soft contact lens wearers should be informed about the effects on optical quality and visual function.

  10. Biodiversity effects in the wild are common and as strong as key drivers of productivity

    Science.gov (United States)

    Duffy, J. Emmett; Godwin, Casey M.; Cardinale, Bradley J.

    2017-09-01

    More than 500 controlled experiments have collectively suggested that biodiversity loss reduces ecosystem productivity and stability. Yet the importance of biodiversity in sustaining the world’s ecosystems remains controversial, largely because of the lack of validation in nature, where strong abiotic forcing and complex interactions are assumed to swamp biodiversity effects. Here we test this assumption by analysing 133 estimates reported in 67 field studies that statistically separated the effects of biodiversity on biomass production from those of abiotic forcing. Contrary to the prevailing opinion of the previous two decades that biodiversity would have rare or weak effects in nature, we show that biomass production increases with species richness in a wide range of wild taxa and ecosystems. In fact, after controlling for environmental covariates, increases in biomass with biodiversity are stronger in nature than has previously been documented in experiments and comparable to or stronger than the effects of other well-known drivers of productivity, including climate and nutrient availability. These results are consistent with the collective experimental evidence that species richness increases community biomass production, and suggest that the role of biodiversity in maintaining productive ecosystems should figure prominently in global change science and policy.

  11. Biodiversity effects in the wild are common and as strong as key drivers of productivity.

    Science.gov (United States)

    Duffy, J Emmett; Godwin, Casey M; Cardinale, Bradley J

    2017-09-14

    More than 500 controlled experiments have collectively suggested that biodiversity loss reduces ecosystem productivity and stability. Yet the importance of biodiversity in sustaining the world's ecosystems remains controversial, largely because of the lack of validation in nature, where strong abiotic forcing and complex interactions are assumed to swamp biodiversity effects. Here we test this assumption by analysing 133 estimates reported in 67 field studies that statistically separated the effects of biodiversity on biomass production from those of abiotic forcing. Contrary to the prevailing opinion of the previous two decades that biodiversity would have rare or weak effects in nature, we show that biomass production increases with species richness in a wide range of wild taxa and ecosystems. In fact, after controlling for environmental covariates, increases in biomass with biodiversity are stronger in nature than has previously been documented in experiments and comparable to or stronger than the effects of other well-known drivers of productivity, including climate and nutrient availability. These results are consistent with the collective experimental evidence that species richness increases community biomass production, and suggest that the role of biodiversity in maintaining productive ecosystems should figure prominently in global change science and policy.

  12. The strong specific effect of coions on micellar growth from molecular-thermodynamic theory.

    Science.gov (United States)

    Koroleva, S V; Victorov, A I

    2014-09-07

    Viscoelastic solutions of ionic surfactants with an added salt exhibit a surprisingly strong dependence of their behavior on the nature of the added coion. We apply a recently proposed molecular-thermodynamic model to elucidate the effect of a coion's specificity on the aggregation of cationic and anionic surfactants. We show that micellar growth and branching are opposed by penetration of coions inside a micelle's corona leading to an increase of the aggregate's preferential curvature. These effects result from hydration/dehydration and dispersion attraction of coions and are only important at high salinity where electrostatic repulsion of coions from the micelle is screened and where branching of micelles and viscosity maxima are observed. At low and medium salinity, the coion plays a minor role; its effect on critical micelle concentration and sphere-to-rod transitions is insignificant. Our molecular-thermodynamic approach describes the specific effects of both counterions and coions and their different roles at different salinity levels based on a unified physical picture.

  13. Planck 2015 results. XV. Gravitational lensing

    CERN Document Server

    Ade, P.A.R.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Bartolo, N.; Basak, S.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J.J.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R.C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Diego, J.M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T.A.; Eriksen, H.K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, A.H.; Jaffe, T.R.; Jones, W.C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Lewis, A.; Liguori, M.; Lilje, P.B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P.M.; Macías-Pérez, J.F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P.G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Nørgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G.W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Spencer, L.D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J.A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Wandelt, B.D.; Wehus, I.K.; White, M.; Yvon, D.; Zacchei, A.

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40 sigma), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator we detect lensing at a significance of 5 sigma. We cross-check the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40lensing potential power spectrum and that found in the best-fitting LCDM model based on the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percent-level measurement of ...

  14. The theory of stochastic cosmological lensing

    Energy Technology Data Exchange (ETDEWEB)

    Fleury, Pierre; Uzan, Jean-Philippe [Institut d' Astrophysique de Paris, UMR 7095 du CNRS, 98 bis Bd Arago, 75014 Paris (France); Larena, Julien, E-mail: fleury@iap.fr, E-mail: j.larena@ru.ac.za, E-mail: uzan@iap.fr [Department of Mathematics, Rhodes University, Grahamstown 6140 (South Africa)

    2015-11-01

    On the scale of the light beams subtended by small sources, e.g. supernovae, matter cannot be accurately described as a fluid, which questions the applicability of standard cosmic lensing to those cases. In this article, we propose a new formalism to deal with small-scale lensing as a diffusion process: the Sachs and Jacobi equations governing the propagation of narrow light beams are treated as Langevin equations. We derive the associated Fokker-Planck-Kolmogorov equations, and use them to deduce general analytical results on the mean and dispersion of the angular distance. This formalism is applied to random Einstein-Straus Swiss-cheese models, allowing us to: (1) show an explicit example of the involved calculations; (2) check the validity of the method against both ray-tracing simulations and direct numerical integration of the Langevin equation. As a byproduct, we obtain a post-Kantowski-Dyer-Roeder approximation, accounting for the effect of tidal distortions on the angular distance, in excellent agreement with numerical results. Besides, the dispersion of the angular distance is correctly reproduced in some regimes.

  15. Room temperature strong coupling effects from single ZnO nanowire microcavity

    KAUST Repository

    Das, Ayan

    2012-05-01

    Strong coupling effects in a dielectric microcavity with a single ZnO nanowire embedded in it have been investigated at room temperature. A large Rabi splitting of ?100 meV is obtained from the polariton dispersion and a non-linearity in the polariton emission characteristics is observed at room temperature with a low threshold of 1.63 ?J/cm2, which corresponds to a polariton density an order of magnitude smaller than that for the Mott transition. The momentum distribution of the lower polaritons shows evidence of dynamic condensation and the absence of a relaxation bottleneck. The polariton relaxation dynamics were investigated by timeresolved measurements, which showed a progressive decrease in the polariton relaxation time with increase in polariton density. © 2012 Optical Society of America.

  16. Global dynamics and bifurcation analysis of a host-parasitoid model with strong Allee effect.

    Science.gov (United States)

    Khan, Abdul Qadeer; Ma, Jiying; Xiao, Dongmei

    2017-12-01

    In this paper, we study the global dynamics and bifurcations of a two-dimensional discrete time host-parasitoid model with strong Allee effect. The existence of fixed points and their stability are analysed in all allowed parametric region. The bifurcation analysis shows that the model can undergo fold bifurcation and Neimark-Sacker bifurcation. As the parameters vary in a small neighbourhood of the Neimark-Sacker bifurcation condition, the unique positive fixed point changes its stability and an invariant closed circle bifurcates from the positive fixed point. From the viewpoint of biology, the invariant closed curve corresponds to the periodic or quasi-periodic oscillations between host and parasitoid populations. Furthermore, it is proved that all solutions of this model are bounded, and there exist some values of the parameters such that the model has a global attractor. These theoretical results reveal the complex dynamics of the present model.

  17. Strong-field effects in Rabi oscillations between a single state and a superposition of states

    International Nuclear Information System (INIS)

    Zhdanovich, S.; Milner, V.; Hepburn, J. W.

    2011-01-01

    Rabi oscillations of quantum population are known to occur in two-level systems driven by spectrally narrow laser fields. In this work we study Rabi oscillations induced by shaped broadband femtosecond laser pulses. Due to the broad spectral width of the driving field, the oscillations are initiated between a ground state and a coherent superposition of excited states, or a ''wave packet,'' rather than a single excited state. Our experiments reveal an intricate dependence of the wave-packet phase on the intensity of the laser field. We confirm numerically that the effect is associated with the strong-field nature of the interaction and provide a qualitative picture by invoking a simple theoretical model.

  18. Bibliometric Study of Scientific Research on Scleral Lenses.

    Science.gov (United States)

    Povedano-Montero, Francisco Javier; Álvarez-Peregrina, Cristina; Hidalgo Santa Cruz, Fernando; Villa-Collar, César; Sánchez Valverde, José

    2018-01-25

    To analyze the state of scientific publications in the field of scleral lenses applying a bibliometric study. The database used in this bibliometric study was SCOPUS, the largest abstract and citation database of peer-reviewed literature: scientific journals, books, and conference proceedings. Using remote download techniques, articles published between 1962 (year of first registrations) and 2015 were selected by entering the main descriptors: "scleral contact lenses" and "scleral lenses," limiting the field for the article, keywords, and abstract, linked with the OR tab. We applied the following bibliometric indicators: Price index, doubling time and annual growth rate, Price transience index, Lotka law of scientific productivity, and Bradford zones. The authors recovered 361 contributions (articles, reviews, letters to the editor, etc.) for 1962 to 2016. The distribution for five-year periods shows a significant increase in 2012 to 2016, with a growth of 222.22% in comparison with the previous period 2012 to 2016. The countries with the highest production are the United states with 135 contributions, United Kingdom with 46, and India with 19. The most productive institutions are Harvard Medical school, Boston Foundation for Sight, and Moorfields Eye Hospital National Health Service Foundation Trust. Classification of authors based on productivity is strongly concentrated in small producers, with a transient index of 59.03. The total number of authors is 891, representing a coauthor index of 2.47 for the 361 documents retrieved. The authors with the highest productivity are Kenneth W. Pullum, Perry Rosenthal, and Deborah S. Jacobs, with an h-index between 12 and 19 documents. The number of documents published on scleral lenses shows a significant increase in the last 5 years, and currently, they represent only 1.44% of all publications on contact lenses. Bibliometric studies have become essential tools for evaluating scientific activity, allowing an overview of

  19. Effects of oral Ginkgo biloba supplementation on cataract formation and oxidative stress occurring in lenses of rats exposed to total cranium radiotherapy

    International Nuclear Information System (INIS)

    Ertekin, M.V.; Kocer, I.; Karslioglu, I.; Taysi, S.; Gepdiremen, A.; Sezen, O.; Balci, E.; Bakan, N.

    2004-01-01

    The objective of this study was to determine the antioxidant role of Ginkgo biloba (GB) in preventing radiation-induced cataracts in the lens after total-cranium irradiation of rats with a single radiation dose of 5 Gy. Sprague-Dawley rats were randomly divided into three groups. Group 1 received neither GB nor irradiation (control group). Group 2 was exposed to total-cranium irradiation of 5 Gy in a single dose [radiation therapy (RT) group], and group 3 received total cranium irradiation from a cobalt-60 teletherapy unit, plus 40 mg/kg per day GB (RT+GB group). At the end of the tenth day, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the lipid peroxidation level [malondialdehyde (MDA)]. Irradiation significantly increased both the MDA level and the activity of GSH-Px, and significantly decreased the activity of SOD in the rat lenses. GB supplementation significantly increased the activities of SOD and GSH-Px enzymes and significantly decreased the MDA level. Total cranium irradiation of 5 Gy in a single dose promoted cataract formation, and GB supplementation protected the lenses from radiation-induced cataracts. We suggest that Grinkgo biloba is an antioxidant that protects the rat lens from radiation-induced cataracts. (author)

  20. Scleral lenses in the management of keratoconus.

    Science.gov (United States)

    Schornack, Muriel M; Patel, Sanjay V

    2010-01-01

    To describe the use of Jupiter scleral lenses (Medlens Innovations, Front Royal, VA; and Essilor Contact Lenses, Inc., Dallas, TX) in the management of keratoconus. We performed a single-center retrospective chart review of our initial 32 patients with keratoconus evaluated for scleral lens wear. All patients were referred for scleral lens evaluation after exhausting other nonsurgical options for visual correction. Diagnostic lenses were used in the initial fitting process. If adequate fit could not be achieved with standard lenses, custom lenses were designed in consultation with the manufacturers' specialists. The following measures were evaluated for each patient: ability to tolerate and handle lenses, visual acuity with scleral lenses, number of lenses, and visits needed to complete the fitting process. Fifty-two eyes of 32 patients were evaluated for scleral lens wear. Of these, 12 patients (20 eyes) decided not to pursue scleral lens wear after initial evaluation. One patient (2 eyes) abandoned the fitting process after cataract surgery. The remaining 19 patients (30 eyes) were fit successfully. The average number of lenses ordered per eye was 1.5. The fitting process required an average of 2.8 visits. Standard lenses were prescribed for 23 eyes, and custom designs were needed for 7 eyes. Median best-corrected visual acuity improved from 20/40 (mean, 20/76) before scleral lens fitting to 20/20 (mean, 20/30) after fitting. Follow-up ranged from 3 to 32 months. Jupiter scleral lenses provide acceptable visual acuity and comfort in patients with keratoconus. The availability of diagnostic lenses facilitates the fitting process.

  1. Channel-closing effects in strong-field ionization by a bicircular field

    Science.gov (United States)

    Milošević, D. B.; Becker, W.

    2018-03-01

    Channel-closing effects, such as threshold anomalies and resonantlike intensity-dependent enhancements in strong-field ionization by a bicircular laser field are analyzed. A bicircular field consists of two coplanar corotating or counter-rotating circularly polarized fields having different frequencies. For the total detachment rate of a negative ion by a bicircular field we observe threshold anomalies and explain them using the Wigner threshold law and energy and angular momentum conservation. For the corotating bicircular case, these effects are negligible, while for the counter-rotating case they are pronounced and their position depends on the magnetic quantum number of the initial state. For high-order above-threshold ionization of rare-gas atoms by a counter-rotating bicircular laser field we observe very pronounced intensity-dependent enhancements. We find all four types of threshold anomalies known from collision theory. Contrary to the case of linear polarization, channel-closing effects for a bicircular field are visible also in the cutoff region of the electron energy spectrum, which is explained using quantum-orbit theory.

  2. Strong quantum-confined stark effect in germanium quantum-well structures on silicon

    International Nuclear Information System (INIS)

    Kuo, Y.; Lee, Y. K.; Gei, Y.; Ren, S; Roth, J. E.; Miller, D. A.; Harris, J. S.

    2006-01-01

    Silicon is the dominant semiconductor for electronics, but there is now a growing need to integrate such component with optoelectronics for telecommunications and computer interconnections. Silicon-based optical modulators have recently been successfully demonstrated but because the light modulation mechanisms in silicon are relatively weak, long (for example, several millimeters) devices or sophisticated high-quality-factor resonators have been necessary. Thin quantum-well structures made from III-V semiconductors such as GaAs, InP and their alloys exhibit the much stronger Quantum-Confined Stark Effect (QCSE) mechanism, which allows modulator structures with only micrometers of optical path length. Such III-V materials are unfortunately difficult to integrate with silicon electronic devices. Germanium is routinely integrated with silicon in electronics, but previous silicon-germanium structures have also not shown strong modulation effects. Here we report the discovery of the QCSE, at room temperature, in thin germanium quantum-well structures grown on silicon. The QCSE here has strengths comparable to that in III-V materials. Its clarity and strength are particularly surprising because germanium is an indirect gap semiconductor, such semiconductors often display much weak optical effects than direct gap materials (such as the III-V materials typically used for optoelectronics). This discovery is very promising for small, high-speed, low-power optical output devices fully compatible with silicon electronics manufacture. (author)

  3. Strong mechanically induced effects in DC current-biased suspended Josephson junctions

    Science.gov (United States)

    McDermott, Thomas; Deng, Hai-Yao; Isacsson, Andreas; Mariani, Eros

    2018-01-01

    Superconductivity is a result of quantum coherence at macroscopic scales. Two superconductors separated by a metallic or insulating weak link exhibit the AC Josephson effect: the conversion of a DC voltage bias into an AC supercurrent. This current may be used to activate mechanical oscillations in a suspended weak link. As the DC-voltage bias condition is remarkably difficult to achieve in experiments, here we analyze theoretically how the Josephson effect can be exploited to activate and detect mechanical oscillations in the experimentally relevant condition with purely DC current bias. We unveil how changing the strength of the electromechanical coupling results in two qualitatively different regimes showing dramatic effects of the oscillations on the DC-voltage characteristic of the device. These include the appearance of Shapiro-type plateaus for weak coupling and a sudden mechanically induced retrapping for strong coupling. Our predictions, measurable in state-of-the-art experimental setups, allow the determination of the frequency and quality factor of the resonator using DC only techniques.

  4. Quasar lenses and galactic streams: outlier selection and Gaia multiplet detection

    Science.gov (United States)

    Agnello, Adriano

    2017-10-01

    I describe two novel techniques originally devised to select strongly lensed quasar candidates in wide-field surveys. The first relies on outlier selection in optical and mid-infrared magnitude space; the second combines mid-infrared colour selection with Gaia spatial resolution, to identify multiplets of objects with quasar-like colours. Both methods have already been applied successfully to the Sloan Digital Sky Survey, ATLAS and Dark Energy Survey footprints: besides recovering known lenses from previous searches, they have led to new discoveries, including quadruply lensed quasars, which are rare within the rare-object class of quasar lenses. As a serendipitous by-product, at least four candidate Galactic streams in the South have been identified among foreground contaminants. There is considerable scope for tailoring the WISE-Gaia multiplet search to stellar-like objects, instead of quasar-like, and to automatically detect Galactic streams.

  5. Biological effects of electromagnetic fields and recently updated safety guidelines for strong static magnetic fields

    International Nuclear Information System (INIS)

    Yamaguchi-Sekino, Sachiko; Sekino, Masaki; Ueno, Shoogo

    2011-01-01

    Humans are exposed daily to artificial and naturally occurring magnetic fields that originate from many different sources. We review recent studies that examine the biological effects of and medical applications involving electromagnetic fields, review the properties of static and pulsed electromagnetic fields that affect biological systems, describe the use of a pulsed electromagnetic field in combination with an anticancer agent as an example of a medical application that incorporates an electromagnetic field, and discuss the recently updated safety guidelines for static electromagnetic fields. The most notable modifications to the 2009 International Commission on Non-Ionizing Radiation Protection guidelines are the increased exposure limits, especially for those who work with or near electromagnetic fields (occupational exposure limits). The recommended increases in exposure were determined using recent scientific evidence obtained from animal and human studies. Several studies since the 1994 publication of the guidelines have examined the effects on humans after exposure to high static electromagnetic fields (up to 9.4 tesla), but additional research is needed to ascertain further the safety of strong electromagnetic fields. (author)

  6. Biological effects of electromagnetic fields and recently updated safety guidelines for strong static magnetic fields.

    Science.gov (United States)

    Yamaguchi-Sekino, Sachiko; Sekino, Masaki; Ueno, Shoogo

    2011-01-01

    Humans are exposed daily to artificial and naturally occurring magnetic fields that originate from many different sources. We review recent studies that examine the biological effects of and medical applications involving electromagnetic fields, review the properties of static and pulsed electromagnetic fields that affect biological systems, describe the use of a pulsed electromagnetic field in combination with an anticancer agent as an example of a medical application that incorporates an electromagnetic field, and discuss the recently updated safety guidelines for static electromagnetic fields. The most notable modifications to the 2009 International Commission on Non-Ionizing Radiation Protection guidelines are the increased exposure limits, especially for those who work with or near electromagnetic fields (occupational exposure limits). The recommended increases in exposure were determined using recent scientific evidence obtained from animal and human studies. Several studies since the 1994 publication of the guidelines have examined the effects on humans after exposure to high static electromagnetic fields (up to 9.4 tesla), but additional research is needed to ascertain further the safety of strong electromagnetic fields.

  7. Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum

    Science.gov (United States)

    Fujiwara, Yoshihisa; Tomishige, Masahiko; Itoh, Yasuhiro; Fujiwara, Masao; Shibata, Naho; Kosaka, Toshikazu; Hosoya, Hiroshi; Tanimoto, Yoshifumi

    2006-05-01

    Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum was studied by using a superconducting magnet. Around a centre of a round vessel, random swimming at 0 T and aligned swimming parallel to the magnetic field (MF) of 8 T were observed. Near a wall of the vessel, however, swimming round and round along the wall at 0 T and aligned swimming of turning at right angles upon collision with the wall, which was remarkable around 1-4 T, were detected. It was experimentally revealed that the former MF-induced parallel swimming at the vessel centre was caused physicochemically by the parallel magnetic orientation of the cell itself. From magnetic field dependence of the extent of the orientation, the magnetic susceptibility anisotropy (χ ∥-χ ⊥) was first obtained to be 3.4× 10-23 emu cell-1 at 298 K for Paramecium caudatum. The orientation of the cell was considered to result from the magnetic orientation of the cell membrane. On the other hand, although mechanisms of the latter swimming near the vessel wall regardless of the absence and presence of the magnetic field are unclear at present, these experimental results indicate that whether the cell exists near the wall alters the magnetic field effect on the swimming in the horizontal magnetic field.

  8. Glutathione preservation during storage of rat lenses in optisol-GS and castor oil.

    Science.gov (United States)

    Holm, Thomas; Brøgger-Jensen, Martin Rocho; Johnson, Leif; Kessel, Line

    2013-01-01

    Glutathione concentration in the lens decreases in aging and cataractous lenses, providing a marker for tissue condition. Experimental procedures requiring unfrozen lenses from donor banks rely on transportation in storage medium, affecting lens homeostasis and alterations in glutathione levels. The aim of the study was to examine the effects of Optisol-GS and castor oil on lens condition, determined from their ability to maintain glutathione concentrations. Rat lenses were stored in the two types of storage media at varying time intervals up to 3 days. Glutathione concentration was afterwards determined in an enzymatic detection assay, specific for both reduced and oxidized forms. Lenses removed immediately after death exhibited a glutathione concentration of 4.70±0.29 mM. In vitro stored lenses in Optisol-GS lost glutathione quickly, ending with a concentration of 0.60±0.34 mM after 3 days while castor oil stored lenses exhibited a slower decline and ended at 3 times the concentration. A group of lenses were additionally stored under post mortem conditions within the host for 6 hours before its removal. Total glutathione after 6 hours was similar to that of lenses removed immediately after death, but with altered GSH and GSSG concentrations. Subsequent storage of these lenses in media showed changes similar to those in the first series of experiments, albeit to a lesser degree. It was determined that storage in Optisol-GS resulted in a higher loss of glutathione than lenses stored in castor oil. Storage for more than 12 hours reduced glutathione to half its original concentration, and was considered unusable after 24 hours.

  9. Glutathione preservation during storage of rat lenses in optisol-GS and castor oil.

    Directory of Open Access Journals (Sweden)

    Thomas Holm

    Full Text Available BACKGROUND: Glutathione concentration in the lens decreases in aging and cataractous lenses, providing a marker for tissue condition. Experimental procedures requiring unfrozen lenses from donor banks rely on transportation in storage medium, affecting lens homeostasis and alterations in glutathione levels. The aim of the study was to examine the effects of Optisol-GS and castor oil on lens condition, determined from their ability to maintain glutathione concentrations. METHODOLOGY/PRINCIPAL FINDINGS: Rat lenses were stored in the two types of storage media at varying time intervals up to 3 days. Glutathione concentration was afterwards determined in an enzymatic detection assay, specific for both reduced and oxidized forms. Lenses removed immediately after death exhibited a glutathione concentration of 4.70±0.29 mM. In vitro stored lenses in Optisol-GS lost glutathione quickly, ending with a concentration of 0.60±0.34 mM after 3 days while castor oil stored lenses exhibited a slower decline and ended at 3 times the concentration. A group of lenses were additionally stored under post mortem conditions within the host for 6 hours before its removal. Total glutathione after 6 hours was similar to that of lenses removed immediately after death, but with altered GSH and GSSG concentrations. Subsequent storage of these lenses in media showed changes similar to those in the first series of experiments, albeit to a lesser degree. CONCLUSIONS/SIGNIFICANCE: It was determined that storage in Optisol-GS resulted in a higher loss of glutathione than lenses stored in castor oil. Storage for more than 12 hours reduced glutathione to half its original concentration, and was considered unusable after 24 hours.

  10. Ultraviolet radiation for the sterilization of contact lenses.

    Science.gov (United States)

    Gritz, D C; Lee, T Y; McDonnell, P J; Shih, K; Baron, N

    1990-01-01

    Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study.

  11. Ultraviolet radiation for the sterilization of contact lenses

    International Nuclear Information System (INIS)

    Gritz, D.C.; Lee, T.Y.; McDonnell, P.J.; Shih, K.; Baron, N.

    1990-01-01

    Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study

  12. Ultraviolet radiation for the sterilization of contact lenses

    Energy Technology Data Exchange (ETDEWEB)

    Gritz, D.C.; Lee, T.Y.; McDonnell, P.J.; Shih, K.; Baron, N. (Univ. of Southern California School of Medicine, Los Angeles (USA))

    1990-10-01

    Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study.

  13. Detailed site effect estimation in the presence of strong velocity reversals within a small-aperture strong-motion array in Iceland

    KAUST Repository

    Rahpeyma, Sahar

    2016-08-11

    The rock site characterization for earthquake engineering applications in Iceland is common due to the easily exposed older bedrock and more recent volcanic lava rock. The corresponding site amplification is generally assumed to be low but has not been comprehensively quantified, especially for volcanic rock. The earthquake strong-motion of the Mw6.3 Ölfus earthquake on 29 May 2008 and 1705 of its aftershocks recorded on the first small-aperture strong-motion array (ICEARRAY I) in Iceland showed consistent and significant variations in ground motion amplitudes over short distances (<2 km) in an urban area located mostly on lava rock. This study analyses the aftershock recordings to quantify the local site effects using the Horizontal to Vertical Spectral Ratio (HVSR) and Standard Spectral Ratio (SSR) methods. Additionally, microseismic data has been collected at array stations and analyzed using the HVSR method. The results between the methods are consistent and show that while the amplification levels remain relatively low, the predominant frequency varies systematically between stations and is found to correlate with the geological units. In particular, for stations on lava rock the underlying geologic structure is characterized by repeated lava-soil stratigraphy characterized by reversals in the shear wave velocity with depth. As a result, standard modeling of HVSR using vertically incident body waves does not apply. Instead, modeling the soil structure as a two-degree-of-freedom dynamic system is found to capture the observed predominant frequencies of site amplification. The results have important implications for earthquake resistant design of structures on rock sites characterized by velocity reversals. © 2016 Elsevier Ltd

  14. The Scales of Gravitational Lensing

    Directory of Open Access Journals (Sweden)

    Francesco De Paolis

    2016-03-01

    Full Text Available After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge of supermassive black holes in the center of ours and nearby galaxies.

  15. Effective potential in the strong-coupling lattice QCD with next-to-next-to-learning order effects

    International Nuclear Information System (INIS)

    Nakano, Takashi Z.; Miura, Kohtaroh; Ohnishi, Akira

    2010-01-01

    We derive an analytic expression of the effective potential at finite temperature (T) and chemical potential (μ) in the strong-coupling lattice QCD for color SU(3) including next-to-next-to-leading order (NNLO) effects in the strong coupling expansion. NNLO effective action terms are systematically evaluated in the leading order of the large dimensional (1/d) expansion, and are found to come from some types of connected two-plaquette configurations. We apply the extended Hubbard-Stratonovich transformation and a gluonic-dressed fermion technique to the effective action, and obtain the effective potential as a function of T, μ, and two order parameters: chiral condensate and vector potential field. The next-to-leading order (NLO) and NNLO effects result in modifications of the wave function renormalization factor, quark mass, and chemical potential. We find that T c,μ =0 and μ c,T =0 are similar to the NLO results, whereas the position of the critical point is sensitive to NNLO corrections. (author)

  16. ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm

    Science.gov (United States)

    Amvrosiadis, A.; Eales, S. A.; Negrello, M.; Marchetti, L.; Smith, M. W. L.; Bourne, N.; Clements, D. L.; De Zotti, G.; Dunne, L.; Dye, S.; Furlanetto, C.; Ivison, R. J.; Maddox, S. J.; Valiante, E.; Baes, M.; Baker, A. J.; Cooray, A.; Crawford, S. M.; Frayer, D.; Harris, A.; Michałowski, M. J.; Nayyeri, H.; Oliver, S.; Riechers, D. A.; Serjeant, S.; Vaccari, M.

    2018-04-01

    With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetre-selected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ˜1013 M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro-Frenk-White profile. We show that we would need a sample of ˜500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys.

  17. ALMA observations of lensed Herschel sources : Testing the dark-matter halo paradigm

    Science.gov (United States)

    Amvrosiadis, A.; Eales, S. A.; Negrello, M.; Marchetti, L.; Smith, M. W. L.; Bourne, N.; Clements, D. L.; De Zotti, G.; Dunne, L.; Dye, S.; Furlanetto, C.; Ivison, R. J.; Maddox, S.; Valiante, E.; Baes, M.; Baker, A. J.; Cooray, A.; Crawford, S. M.; Frayer, D.; Harris, A.; Michałowski, M. J.; Nayyeri, H.; Oliver, S.; Riechers, D. A.; Serjeant, S.; Vaccari, M.

    2018-01-01

    With the advent of wide-area submillimeter surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies (DSFGs) has been revealed. Due to the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimeter surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetre-selected sources by making observations with the Atacama Large Millimetre Array (ALMA) of a sample of strongly-lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation which contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the halos formed in the EAGLE simulation and two density distributions (Singular Isothermal Sphere (SIS) and SISSA) that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ˜1013M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by an NFW profile. We show that we would need a sample of ˜500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys.

  18. Precision cosmology from future lensed gravitational wave and electromagnetic signals.

    Science.gov (United States)

    Liao, Kai; Fan, Xi-Long; Ding, Xuheng; Biesiada, Marek; Zhu, Zong-Hong

    2017-10-27

    The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts. It is limited by the calibration uncertainties in strain amplitude and relies on the fine details of the waveform. The Einstein telescope is expected to produce 10 4 -10 5 gravitational wave detections per year, 50-100 of which will be lensed. Here, we report a waveform-independent strategy to achieve precise cosmography by combining the accurately measured time delays from strongly lensed gravitational wave signals with the images and redshifts observed in the electromagnetic domain. We demonstrate that just 10 such systems can provide a Hubble constant uncertainty of 0.68% for a flat lambda cold dark matter universe in the era of third-generation ground-based detectors.

  19. Experimental studies of stable confined electron clouds using Gabor lenses

    CERN Document Server

    Meusel, O.; Glaeser, B.; Schulte, K.

    2013-04-22

    Based on the idea of D. Gabor [1] space charge lenses are under investigation to be a powerful focussing device for intense ion beams. A stable confined electron column is used to provide strong radially symmetric electrostatic focussing, e.g. for positively charged ion beams. The advantages of Gabor lenses are a mass independent focussing strength, space charge compensation of the ion beam and reduced magnetic or electric fields compared to conventional focussing devices. Collective phenomena of the electron cloud result in aberrations and emittance growth of the ion beam. The knowledge of the behaviour of the electron cloud prevents a decrease of the beam brilliance. Numerical models developed to describe the electron confinement and dynamics within a Gabor lens help to understand the interaction of the ion beam with the electron column and show the causes of non-neutral plasma instabilities. The diagnosis of the electron cloud properties helps to evaluate the numerical models and to investigate the influen...

  20. Disorder effects on helical edge transport in graphene under a strong tilted magnetic field

    Science.gov (United States)

    Huang, Chunli; Cazalilla, Miguel A.

    2015-10-01

    In a recent experiment, Young et al. [Nature (London) 505, 528 (2014), 10.1038/nature12800] observed a metal to insulator transition as well as transport through helical edge states in monolayer graphene under a strong, tilted magnetic field. Under such conditions, the bulk is a magnetic insulator which can exhibit metallic conduction through helical edges. It was found that the two-terminal conductance of the helical channels deviates from the expected quantized value (=e2/h per edge, at zero temperature). Motivated by this observation, we study the effect of disorder on the conduction through the edge channels. We show that, unlike for helical edges of topological insulators in semiconducting quantum wells, a disorder Rashba spin-orbit coupling does not lead to backscattering, at least to leading order. Instead, we find that the lack of perfect antialignment of the electron spins in the helical channels to be the most likely cause for backscattering arising from scalar (i.e., spin-independent) impurities. The intrinsic spin-orbit coupling and other time-reversal symmetry-breaking and/or sublattice parity-breaking potentials also lead to (subleading) corrections to the channel conductance.

  1. Effect of dipole polarizability on positron binding by strongly polar molecules

    International Nuclear Information System (INIS)

    Gribakin, G F; Swann, A R

    2015-01-01

    A model for positron binding to polar molecules is considered by combining the dipole potential outside the molecule with a strongly repulsive core of a given radius. Using existing experimental data on binding energies leads to unphysically small core radii for all of the molecules studied. This suggests that electron–positron correlations neglected in the simple model play a large role in determining the binding energy. We account for these by including the polarization potential via perturbation theory and non-perturbatively. The perturbative model makes reliable predictions of binding energies for a range of polar organic molecules and hydrogen cyanide. The model also agrees with the linear dependence of the binding energies on the polarizability inferred from the experimental data (Danielson et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 235203). The effective core radii, however, remain unphysically small for most molecules. Treating molecular polarization non-perturbatively leads to physically meaningful core radii for all of the molecules studied and enables even more accurate predictions of binding energies to be made for nearly all of the molecules considered. (paper)

  2. Strong gravity effects of rotating black holes: quasi-periodic oscillations

    International Nuclear Information System (INIS)

    Aliev, Alikram N; Esmer, Göksel Daylan; Talazan, Pamir

    2013-01-01

    We explore strong gravity effects of the geodesic motion in the spacetime of rotating black holes in general relativity and braneworld gravity. We focus on the description of the motion in terms of three fundamental frequencies: the orbital frequency, the radial and vertical epicyclic frequencies. For a Kerr black hole, we perform a detailed numerical analysis of these frequencies at the innermost stable circular orbits and beyond them as well as at the characteristic stable orbits, at which the radial epicyclic frequency attains its highest value. We find that the values of the epicyclic frequencies for a class of stable orbits exhibit good qualitative agreement with the observed frequencies of the twin peaks quasi-periodic oscillations (QPOs) in some black hole binaries. We also find that at the characteristic stable circular orbits, where the radial (or the vertical) epicyclic frequency has maxima, the vertical and radial epicyclic frequencies exhibit an approximate 2:1 ratio even in the case of near-extreme rotation of the black hole. Next, we perform a similar analysis of the fundamental frequencies for a rotating braneworld black hole and argue that the existence of such a black hole with a negative tidal charge, whose angular momentum exceeds the Kerr bound in general relativity, does not confront with the observations of high-frequency QPOs. (paper)

  3. Peak ground motions, effective duration of strong motions and frequency content of Iranian earthquakes

    International Nuclear Information System (INIS)

    Tehranizadeh, M.; Hamedi, F.

    2002-01-01

    The characteristics of earthquake ground motion have great influences on the response of structures to the earthquakes. Peak ground motions, duration of strong motions and frequency content are important characteristics of earthquakes, which are studied in this paper. The relation between peak ground acceleration, velocity and displacement have been taken into account and the effects of magnitude, epicentral distance and recorded duration of earthquakes on peak ground acceleration have been presented as graphs. The frequency content of ground motion can be examined by power spectral density of accel ero grams. In this study the power spectral density of the records have been determined and normalized power spectral densities are compared. There are different formulas for the smoothed power spectral density function such as Kanai-Tajimi's model. In this study, comparing with Kanai-Tajim's formula, the extreme value model is suggested for the spectral density function. This model is evaluated for accel ero grams on different soil conditions and the smoothed mean power spectral density function are determined for each soil groups. The central frequency and predominant period of earthquakes are also estimated

  4. The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chihway; et al.

    2017-10-18

    Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The cluster-centric radius at which this process occurs, r_sp, defines a halo boundary that is connected to the dynamics of the cluster, in contrast with other common halo boundary definitions such as R_200. A rapid decline in the matter density profile of the halo is expected near r_sp. We measure the galaxy number density and weak lensing mass profiles around RedMapper galaxy clusters in the first year Dark Energy Survey (DES) data. For a cluster sample with mean mass ~2.5 x 10^14 solar masses, we find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_sp=1.16 +/- 0.08 Mpc/h, consistent with earlier SDSS measurements of More et al. (2016) and Baxter et al. (2017). Moreover, our weak lensing measurement demonstrates for the first time the existence of a splashback-like steepening of the matter profile of galaxy clusters. We measure r_sp=1.28 +/- 0.18 Mpc/h from the weak lensing data, in good agreement with our galaxy density measurements. Applying our analysis to different cluster and galaxy samples, we find that consistent with LambdaCDM simulations, r_sp scales with R_200m and does not evolve with redshift over the redshift range of 0.3--0.6. We also find that potential systematic effects associated with the RedMapper algorithm may impact the location of r_sp, in particular the choice of scale used to estimate cluster richness. We discuss progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples.

  5. Modern scleral lenses part I: clinical features.

    NARCIS (Netherlands)

    Visser, E.S.; Visser, R.; Lier, H.J.J. van; Otten, H.M.

    2007-01-01

    PURPOSE: To evaluate the indications for modern scleral lenses and their clinical performance in patients who were fitted with scleral lenses at the authors' practices. METHODS: In this cross-sectional survey, all the necessary data were obtained at the first follow-up visit during the 5-month study

  6. Galaxy-galaxy lensing estimators and their covariance properties

    Science.gov (United States)

    Singh, Sukhdeep; Mandelbaum, Rachel; Seljak, Uroš; Slosar, Anže; Vazquez Gonzalez, Jose

    2017-11-01

    We study the covariance properties of real space correlation function estimators - primarily galaxy-shear correlations, or galaxy-galaxy lensing - using SDSS data for both shear catalogues and lenses (specifically the BOSS LOWZ sample). Using mock catalogues of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the lens density field instead of the lens overdensity field. While the measurement using the lens density field is unbiased (in the absence of systematics), its error is significantly larger due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the overdensity, we find that the errors are dominated by the shape noise and lens clustering, which empirically estimated covariances (jackknife and standard deviation across mocks) that are consistent with theoretical estimates, and that both the connected parts of the four-point function and the supersample covariance can be neglected for the current levels of noise. While the trade-off between different terms in the covariance depends on the survey configuration (area, source number density), the diagnostics that we use in this work should be useful for future works to test their empirically determined covariances.

  7. Strong mutagenic effects of diesel engine emissions using vegetable oil as fuel.

    Science.gov (United States)

    Bünger, Jürgen; Krahl, Jürgen; Munack, Axel; Ruschel, Yvonne; Schröder, Olaf; Emmert, Birgit; Westphal, Götz; Müller, Michael; Hallier, Ernst; Brüning, Thomas

    2007-08-01

    Diesel engine emissions (DEE) are classified as probably carcinogenic to humans. In recent years every effort was made to reduce DEE and their content of carcinogenic and mutagenic polycyclic aromatic compounds. Since 1995 we observed an appreciable reduction of mutagenicity of DEE driven by reformulated or newly designed fuels in several studies. Recently, the use of rapeseed oil as fuel for diesel engines is rapidly growing among German transportation businesses and agriculture due to economic reasons. We compared the mutagenic effects of DEE from two different batches of rapeseed oil (RSO) with rapeseed methyl ester (RME, biodiesel), natural gas derived synthetic fuel (gas-to-liquid, GTL), and a reference diesel fuel (DF). The test engine was a heavy-duty truck diesel running the European Stationary Cycle. Particulate matter from the exhaust was sampled onto PTFE-coated glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The gas phase constituents were sampled as condensates. The mutagenicity of the particle extracts and the condensates was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Compared to DF the two RSO qualities significantly increased the mutagenic effects of the particle extracts by factors of 9.7 up to 59 in tester strain TA98 and of 5.4 up to 22.3 in tester strain TA100, respectively. The condensates of the RSO fuels caused an up to factor 13.5 stronger mutagenicity than the reference fuel. RME extracts had a moderate but significant higher mutagenic response in assays of TA98 with metabolic activation and TA100 without metabolic activation. GTL samples did not differ significantly from DF. In conclusion, the strong increase of mutagenicity using RSO as diesel fuel compared to the reference DF and other fuels causes deep concern on future usage of this biologic resource as a replacement of established diesel fuels.

  8. Autler-Townes effect in a strongly driven electromagnetically induced transparency resonance

    International Nuclear Information System (INIS)

    Yang Lijun; Zhang Lianshui; Li Xiaoli; Han Li; Fu Guangsheng; Manson, Neil B.; Suter, Dieter; Wei Changjiang

    2005-01-01

    In this paper we study the nonlinear behavior of an electromagnetically induced transparency (EIT) resonance subject to a coherent driving field. The EIT is associated with a Λ three-level system where two hyperfine levels within an electronic ground state are coupled to a common excited state level by a coupling field and a probe field. In addition there is an radio-frequency (rf) field driving a hyperfine transition within the ground state. The paper contrasts two different situations. In one case the rf-driven transition shares a common level with the probed transition and in the second case it shares a common level with the coupled transition. In both cases the EIT resonance is split into a doublet and the characteristics of the EIT doublet are determined by the strength and frequency of the rf-driving field. The doublet splitting originates from the rf-field induced dynamic Stark effect and has close analogy with the Autler-Townes effect observed in three-level pump-probe spectroscopy study. The situation changes when the rf field is strong and the two cases are very different. One is analogous to two Λ three-level systems with EIT resonance associated with each. The other corresponds to a doubly driven three-level system with rf-field-induced electromagnetically induced absorption resonance. The two situations are modeled using numerical solutions of the relevant equation of motion of density matrix. In addition a physical account of their behaviors is given in terms of a dressed state picture

  9. Lensing-induced morphology changes in CMB temperature maps in modified gravity theories

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, D.; Coles, P. [Astronomy Centre, School of Mathematical and Physical Sciences, University of Sussex, Brighton BN1 9QH (United Kingdom); Hu, B. [Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E08028 Barcelona (Spain); Matsubara, T. [Kobayashi-Maskawa Institute, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Heavens, A., E-mail: D.Munshi@sussex.ac.uk, E-mail: binhu@icc.ub.edu, E-mail: taka@kmi.nagoya-u.ac.jp, E-mail: P.Coles@sussex.ac.uk, E-mail: a.heavens@imperial.ac.uk [Imperial Centre for Inference and Cosmology, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2016-04-01

    Lensing of the Cosmic Microwave Background (CMB) changes the morphology of pattern of temperature fluctuations, so topological descriptors such as Minkowski Functionals can probe the gravity model responsible for the lensing. We show how the recently introduced two-to-two and three-to-one kurt-spectra (and their associated correlation functions), which depend on the power spectrum of the lensing potential, can be used to probe modified gravity theories such as f ( R ) theories of gravity and quintessence models. We also investigate models based on effective field theory, which include the constant-Ω model, and low-energy Hořava theories. Estimates of the cumulative signal-to-noise for detection of lensing-induced morphology changes, reaches O(10{sup 3}) for the future planned CMB polarization mission COrE{sup +}. Assuming foreground removal is possible to ℓ{sub max}=3000, we show that many modified gravity theories can be rejected with a high level of significance, making this technique comparable in power to galaxy weak lensing or redshift surveys. These topological estimators are also useful in distinguishing lensing from other scattering secondaries at the level of the four-point function or trispectrum. Examples include the kinetic Sunyaev-Zel'dovich (kSZ) effect which shares, with lensing, a lack of spectral distortion. We also discuss the complication of foreground contamination from unsubtracted point sources.

  10. Class B0631+519: Last of the Class Lenses

    Energy Technology Data Exchange (ETDEWEB)

    York, Tom; Jackson, N.; Browne, I.W.A.; Koopmans, L.V.E.; McKean, J.P.; Norbury, M.A.; Biggs, A.D.; Blandford, R.D.; de Bruyn, A.G.; Fassnacht, C.D.; Myers, S.T.; Pearson, T.J.; Phillips, P.M.; Readhead, A.C.S.; Rusin, D.; Wilkinson, P.N.; /Jodrell Bank /Kapteyn Astron. Inst., Groningen /UC, Davis /JIVE, Dwingeloo /KIPAC, Menlo Park /NFRA,

    2005-05-31

    We report the discovery of the new gravitational lens system CLASS B0631+519. Imaging with the VLA, MERLIN and the VLBA reveals a doubly-imaged flat-spectrum radio core, a doubly-imaged steep-spectrum radio lobe and possible quadruply-imaged emission from a second lobe. The maximum separation between the lensed images is 1.16 arcsec. High resolution mapping with the VLBA at 5 GHz resolves the most magnified image of the radio core into a number of sub-components spread across approximately 20 mas. No emission from the lensing galaxy or an odd image is detected down to 0.31 mJy (5{sigma}) at 8.4 GHz. Optical and near-infrared imaging with the ACS and NICMOS cameras on the HST show that there are two galaxies along the line of sight to the lensed source, as previously discovered by optical spectroscopy. We find that the foreground galaxy at z=0.0896 is a small irregular, and that the other, at z=0.6196 is a massive elliptical which appears to contribute the majority of the lensing effect. The host galaxy of the lensed source is detected in the HST near-infrared imaging as a set of arcs, which form a nearly complete Einstein ring. Mass modeling using non-parametric techniques can reproduce the near-infrared observations and indicates that the small irregular galaxy has a (localized) effect on the flux density distribution in the Einstein ring at the 5-10% level.

  11. Visual management of aphakia with concomitant severe corneal irregularity by mini-scleral design contact lenses

    Directory of Open Access Journals (Sweden)

    Fateme Alipur

    2016-03-01

    Conclusion: Miniscleral contact lenses can be considered a safe and effective option in aphakia patients with concurrent corneal scarring secondary to ocular injury for whom surgical intervention would be complicated.

  12. Effects of the Coulomb potential in interference patterns of strong-field holography with photoelectrons

    Science.gov (United States)

    Shvetsov-Shilovski, N. I.; Lein, M.

    2018-01-01

    Using the semiclassical two-step model for strong-field ionization we investigate the interference structures emerging in strong-field photoelectron holography, taking into account the Coulomb potential of the atomic core. For every kind of the interference pattern predicted by the three-step model, we calculate the corresponding structure in the presence of the Coulomb field, showing that the Coulomb potential modifies the interference patterns significantly.

  13. Modeling consequences of prolonged strong unpredictable stress in zebrafish: Complex effects on behavior and physiology.

    Science.gov (United States)

    Song, Cai; Liu, Bai-Ping; Zhang, Yong-Ping; Peng, Zhilan; Wang, JiaJia; Collier, Adam D; Echevarria, David J; Savelieva, Katerina V; Lawrence, Robert F; Rex, Christopher S; Meshalkina, Darya A; Kalueff, Allan V

    2018-02-02

    Chronic stress is the major pathogenetic factor of human anxiety and depression. Zebrafish (Danio rerio) have become a novel popular model species for neuroscience research and CNS drug discovery. The utility of zebrafish for mimicking human affective disorders is also rapidly growing. Here, we present a new zebrafish model of clinically relevant, prolonged unpredictable strong chronic stress (PUCS). The 5-week PUCS induced overt anxiety-like and motor retardation-like behaviors in adult zebrafish, also elevating whole-body cortisol and proinflammatory cytokines - interleukins IL-1β and IL-6. PUCS also elevated whole-body levels of the anti-inflammatory cytokine IL-10 and increased the density of dendritic spines in zebrafish telencephalic neurons. Chronic treatment of fish with an antidepressant fluoxetine (0.1mg/L for 8days) normalized their behavioral and endocrine phenotypes, as well as corrected stress-elevated IL-1β and IL-6 levels, similar to clinical and rodent data. The CNS expression of the bdnf gene, the two genes of its receptors (trkB, p75), and the gfap gene of glia biomarker, the glial fibrillary acidic protein, was unaltered in all three groups. However, PUCS elevated whole-body BDNF levels and the telencephalic dendritic spine density (which were corrected by fluoxetine), thereby somewhat differing from the effects of chronic stress in rodents. Together, these findings support zebrafish as a useful in-vivo model of chronic stress, also calling for further cross-species studies of both shared/overlapping and distinct neurobiological responses to chronic stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Effects of strong bite force on the facial vertical dimension of pembarong performers

    Directory of Open Access Journals (Sweden)

    C. Christina

    2017-06-01

    Full Text Available Background: A pembarong performer is a reog dancer who bites on a piece of wood inserted into his/her mouth in order to support a 60 kg Barongan or Dadak Merak mask. The teeth supporting this large and heavy mask are directly affected, as the strong bite force exerted during a dance could affect their vertical and sagital facial dimensions. Purpose: This study aimed to examine the influence of the bite force of pembarong performers due to their vertical and sagital facial dimensions. Methods: The study reported here involved fifteen pembarong performers and thirteen individuals with normal occlusion (with specific criteria. The bite force of these subjects was measured with a dental prescale sensor during its centric occlusion. A cephalometric variation measurement was subsequently performed on all subjects with its effects on their vertical and sagital facial dimensions being measured. Results: The bite force value of the pembarong performers was 394.3816 ± 7.68787 Newtons, while the normal occlusion was 371.7784 ± 4.77791 Newtons. There was no correlation between the bite force and the facial sagital dimension of these subjects. However, a significant correlation did exist between bite force and lower facial height/total facial height (LFH/TFH ratio (p = 0.013. Conversely, no significant correlation between bite force and posterior facial height/total facial height (PFH/TFH ratio (p = 0.785 was detected. There was an inverse correlation between bite force and LFH/TFH ratio (r = -.464. Conclusion: Bite force is directly related to the decrease in LFH/TFH ratio. Occlusal pressure exerted by the posterior teeth on the alveolar bone may increase bone density at the endosteal surface of cortical bone.

  15. Strong and nonlinear effects of fragmentation on ecosystem service provision at multiple scales

    Science.gov (United States)

    Mitchell, Matthew G. E.; Bennett, Elena M.; Gonzalez, Andrew

    2015-09-01

    Human actions, such as converting natural land cover to agricultural or urban land, result in the loss and fragmentation of natural habitat, with important consequences for the provision of ecosystem services. Such habitat loss is especially important for services that are supplied by fragments of natural land cover and that depend on flows of organisms, matter, or people across the landscape to produce benefits, such as pollination, pest regulation, recreation and cultural services. However, our quantitative knowledge about precisely how different patterns of landscape fragmentation might affect the provision of these types of services is limited. We used a simple, spatially explicit model to evaluate the potential impact of natural land cover loss and fragmentation on the provision of hypothetical ecosystem services. Based on current literature, we assumed that fragments of natural land cover provide ecosystem services to the area surrounding them in a distance-dependent manner such that ecosystem service flow depended on proximity to fragments. We modeled seven different patterns of natural land cover loss across landscapes that varied in the overall level of landscape fragmentation. Our model predicts that natural land cover loss will have strong and unimodal effects on ecosystem service provision, with clear thresholds indicating rapid loss of service provision beyond critical levels of natural land cover loss. It also predicts the presence of a tradeoff between maximizing ecosystem service provision and conserving natural land cover, and a mismatch between ecosystem service provision at landscape versus finer spatial scales. Importantly, the pattern of landscape fragmentation mitigated or intensified these tradeoffs and mismatches. Our model suggests that managing patterns of natural land cover loss and fragmentation could help influence the provision of multiple ecosystem services and manage tradeoffs and synergies between services across different human

  16. The Origin of Gravitational Lensing: A Postscript to Einstein's 1936 Science Paper

    Science.gov (United States)

    Renn; Sauer; Stachel

    1997-01-10

    Gravitational lensing, now taken as an important astrophysical consequence of the general theory of relativity, was found even before this theory was formulated but was discarded as a speculative idea without any chance of empirical confirmation. Reconstruction of some of Einstein's research notes dating back to 1912 reveals that he explored the possibility of gravitational lensing 3 years before completing his general theory of relativity. On the basis of preliminary insights into this theory, Einstein had already derived the basic features of the lensing effect. When he finally published the very same results 24 years later, it was only in response to prodding by an amateur scientist.

  17. Influence of the cosmological constant on gravitational lensing in small systems

    International Nuclear Information System (INIS)

    Sereno, Mauro

    2008-01-01

    The cosmological constant Λ affects gravitational lensing phenomena. The contribution of Λ to the observable angular positions of multiple images and to their amplification and time delay is here computed through a study of the weak deflection limit of the equations of motion in the Schwarzschild-de Sitter metric. Because of Λ the unresolved images are slightly demagnified, the radius of the Einstein ring decreases, and the time delay increases. The effect is however negligible for near lenses. In the case of a null cosmological constant, we provide some updated results on lensing by a Schwarzschild black hole

  18. Process equipped with a sloped UV lamp for the fabrication of gradient-refractive-index lenses.

    Science.gov (United States)

    Liu, Jui-Hsiang; Chiu, Yi-Hong

    2009-05-01

    In this investigation, a method for the preparation of gradient-refractive-index (GRIN) lenses by UV-energy-controlled polymerization has been developed. A glass reaction tube equipped with a sloped UV lamp was designed. Methyl methacrylate and diphenyl sulfide were used as the reactive monomer and nonreactive dopant, respectively. Ciba IRGACURE 184 (1-hydroxy-cyclohexyl-phenyl-ketone) was used as the initiator. The effects of initiator concentration, the addition of acrylic polymers, and the preparation conditions on the optical characteristics of the GRIN lenses produced by this method were also investigated. Refractive index distributions and image transmission properties were estimated for all GRIN lenses prepared.

  19. Oxygen permeability of soft contact lenses in different pH, osmolality and buffering solution

    Directory of Open Access Journals (Sweden)

    Se Eun Lee

    2015-10-01

    Full Text Available AIM: To determine the effect of pH, osmolality, and buffering system on the oxygen permeability (Dk of soft contact lenses.METHODS: Two hydrogel lenses (nelfilcon A and etafilcon A and 2 silicone hydrogel lenses (lotrafilcon A and balafilcon A were used in the study. These lenses were incubated in phosphate-buffered saline (PBS and borate-buffered saline (BBS solutions adjusted by 0.8 pH increments to a pH in the range of 5.8-9.0 or in hypotonic (280 mOsmol/kg, isotonic (310 mOsmol/kg and hypertonic (380 mOsmol/kg PBS solutions. Polarographic method was used for measuring the Dk and lenses were stacked as 4 layers to correct the boundary effect.RESULTS: Dk values of all contact lenses measured in BBS solutions were more stable than those in PBS solutions. Especially the etafilcon A lens showed a relative big change compared with other types of contact lenses at the same conditions. When the osmolality of PBS solution increased from hypotonic to hypertonic, Dk of all contact lenses decreased. Variations in Dk existed depending on lens materials, etafilcon A lens was the most affected and nelfilcon A was the least affected by osmolality.CONCLUSION:From the result obtained, it is revealed that Dk of contact lenses is changed by the pH, osmolality, and buffering condition of tear. Thus, Dk of contact lens can be varied by the lens wearers'' physiological and/or pathological conditions.

  20. Noise Estimates for Measurements of Weak Lensing from the Lyman-alpha Forest

    Science.gov (United States)

    Metcalf, R. Benton; Croft, Rupert A. C.; Romeo, Alessandro

    2018-03-01

    Lensing changes the apparent separation between pixels in the Lyman-α forest of separate quasars or high redshift objects by changing their observed positions on the sky. This changes the implied correlations in the absorption and in particular makes the Lyman-α forest correlation function, or power spectrum, locally anisotropic in the plane of the sky. We have proposed a method for measuring weak lensing using this effect. Here we estimate the noise expected in weak lensing maps and power spectra for different sets of observational parameters. We find that surveys of the size and quality of the ones being done today and ones planned for the future will be able to measure the lensing power spectrum at a source redshift of z ≃ 2.5 with high precision and even be able to image the distribution of foreground matter with high fidelity on degree scales. For example, we predict that Lyman-α forest lensing measurements from the DESI and WEAVE surveys should yield the mass fluctuation amplitude with a statistical error of ˜3%, eBOSS ˜6%. and the proposed MSE survey less than 1%. By dividing the redshift range into multiple bins some tomographic lensing information should be accessible as well. This would allow for cosmological lensing measurements at higher redshift than are accessible with galaxy shear surveys and correspondingly better constraints on the evolution of dark energy at relatively early times.

  1. Ocular Drug Delivery through pHEMA-Hydrogel Contact Lenses Co-Loaded with Lipophilic Vitamins

    Science.gov (United States)

    Lee, Dasom; Cho, Seungkwon; Park, Hwa Sung; Kwon, Inchan

    2016-09-01

    Ocular drug delivery through hydrogel contact lenses has great potential for the treatment of ocular diseases. Previous studies showed that the loading of lipophilic vitamin E to silicone-hydrogel contact lenses was beneficial in ocular drug delivery. We hypothesized that vitamin E loading to another type of popular hydrogel contact lenses, pHEMA-hydrogel contact lenses, improves ocular drug delivery by increasing the drug loading or the duration of drug release. Loading of vitamin E to pHEMA-hydrogel contact lenses significantly increased the loading of a hydrophilic drug surrogate (Alexa Fluor 488 dye) and two hydrophilic glaucoma drugs (timolol and brimonidine) to the lenses by 37.5%, 19.1%, and 18.7%, respectively. However, the release duration time was not significantly altered. Next, we hypothesized that the lipophilic nature of vitamin E attributes to the enhanced drug loading. Therefore, we investigated the effects of co-loading of another lipophilic vitamin, vitamin A, on drug surrogate delivery. We found out that vitamin A loading also increased the loading of the drug surrogate to pHEMA-hydrogel contact lenses by 30.3%. Similar to vitamin E loading, vitamin A loading did not significantly alter the release duration time of the drug or drug surrogate.

  2. MUSE spectroscopy and deep observations of a unique compact JWST target, lensing cluster CLIO

    Science.gov (United States)

    Griffiths, Alex; Conselice, Christopher J.; Alpaslan, Mehmet; Frye, Brenda L.; Diego, Jose M.; Zitrin, Adi; Yan, Haojing; Ma, Zhiyuan; Barone-Nugent, Robert; Bhatawdekar, Rachana; Driver, Simon P.; Robotham, Aaron S. G.; Windhorst, Rogier A.; Wyithe, J. Stuart B.

    2018-04-01

    We present the results of a VLT MUSE/FORS2 and Spitzer survey of a unique compact lensing cluster CLIO at z = 0.42, discovered through the GAMA survey using spectroscopic redshifts. Compact and massive clusters such as this are understudied, but provide a unique prospective on dark matter distributions and for finding background lensed high-z galaxies. The CLIO cluster was identified for follow-up observations due to its almost unique combination of high-mass and dark matter halo concentration, as well as having observed lensing arcs from ground-based images. Using dual band optical and infra-red imaging from FORS2 and Spitzer, in combination with MUSE optical spectroscopy we identify 89 cluster members and find background sources out to z = 6.49. We describe the physical state of this cluster, finding a strong correlation between environment and galaxy spectral type. Under the assumption of an NFW profile, we measure the total mass of CLIO to be M200 = (4.49 ± 0.25) × 1014 M⊙. We build and present an initial strong-lensing model for this cluster, and measure a relatively low intracluster light (ICL) fraction of 7.21 ± 1.53 per cent through galaxy profile fitting. Due to its strong potential for lensing background galaxies and its low ICL, the CLIO cluster will be a target for our 110 h James Webb Space Telescope `Webb Medium-Deep Field' (WMDF) GTO program.

  3. Predicting weak lensing statistics from halo mass reconstructions - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Spencer [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    As dark matter does not absorb or emit light, its distribution in the universe must be inferred through indirect effects such as the gravitational lensing of distant galaxies. While most sources are only weakly lensed, the systematic alignment of background galaxies around a foreground lens can constrain the mass of the lens which is largely in the form of dark matter. In this paper, I have implemented a framework to reconstruct all of the mass along lines of sight using a best-case dark matter halo model in which the halo mass is known. This framework is then used to make predictions of the weak lensing of 3,240 generated source galaxies through a 324 arcmin² field of the Millennium Simulation. The lensed source ellipticities are characterized by the ellipticity-ellipticity and galaxy-mass correlation functions and compared to the same statistic for the intrinsic and ray-traced ellipticities. In the ellipticity-ellipticity correlation function, I and that the framework systematically under predicts the shear power by an average factor of 2.2 and fails to capture correlation from dark matter structure at scales larger than 1 arcminute. The model predicted galaxy-mass correlation function is in agreement with the ray-traced statistic from scales 0.2 to 0.7 arcminutes, but systematically underpredicts shear power at scales larger than 0.7 arcminutes by an average factor of 1.2. Optimization of the framework code has reduced the mean CPU time per lensing prediction by 70% to 24 ± 5 ms. Physical and computational shortcomings of the framework are discussed, as well as potential improvements for upcoming work.

  4. Scanning Miniature Microscopes without Lenses

    Science.gov (United States)

    Wang, Yu

    2009-01-01

    The figure schematically depicts some alternative designs of proposed compact, lightweight optoelectronic microscopes that would contain no lenses and would generate magnified video images of specimens. Microscopes of this type were described previously in Miniature Microscope Without Lenses (NPO - 20218), NASA Tech Briefs, Vol. 22, No. 8 (August 1998), page 43 and Reflective Variants of Miniature Microscope Without Lenses (NPO 20610), NASA Tech Briefs, Vol. 26, No. 9 (September 1999), page 6a. To recapitulate: In the design and construction of a microscope of this type, the focusing optics of a conventional microscope are replaced by a combination of a microchannel filter and a charge-coupled-device (CCD) image detector. Elimination of focusing optics reduces the size and weight of the instrument and eliminates the need for the time-consuming focusing operation. The microscopes described in the cited prior articles contained two-dimensional CCDs registered with two-dimensional arrays of microchannels and, as such, were designed to produce full two-dimensional images, without need for scanning. The microscopes of the present proposal would contain one-dimensional (line image) CCDs registered with linear arrays of microchannels. In the operation of such a microscope, one would scan a specimen along a line perpendicular to the array axis (in other words, one would scan in pushbroom fashion). One could then synthesize a full two-dimensional image of the specimen from the line-image data acquired at one-pixel increments of position along the scan. In one of the proposed microscopes, a beam of unpolarized light for illuminating the specimen would enter from the side. This light would be reflected down onto the specimen by a nonpolarizing beam splitter attached to the microchannels at their lower ends. A portion of the light incident on the specimen would be reflected upward, through the beam splitter and along the microchannels, to form an image on the CCD. If the

  5. Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Previtali, Valentina [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Valishev, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Bruce, Roderik [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Redaelli, Stefano [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Rossi, Adriana [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Salvachua Ferrando, Belen [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2014-06-26

    Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. We are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.

  6. LENS MODEL AND TIME DELAY PREDICTIONS FOR THE SEXTUPLY LENSED QUASAR SDSS J2222+2745

    Energy Technology Data Exchange (ETDEWEB)

    Sharon, Keren; Johnson, Traci L.; Paterno-Mahler, Rachel [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Bayliss, Matthew B. [Colby College, 5800 Mayflower Hill, Waterville, 04901, Maine (United States); Dahle, Håkon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Florian, Michael K.; Gladders, Michael D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Rigby, Jane R. [Astrophysics Science Division, Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Whitaker, Katherine E. [Department of Astronomy, University of Massachusetts-Amherst, Amherst, MA 01003 (United States); Wuyts, Eva, E-mail: kerens@umich.edu [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, D-85741 Garching (Germany)

    2017-01-20

    SDSS J2222+2745 is a galaxy cluster at z = 0.49, strongly lensing a quasar at z = 2.805 into six widely separated images. In recent Hubble Space Telescope imaging of the field, we identify additional multiply lensed galaxies and confirm the sixth quasar image that was identified by Dahle et al. We used the Gemini-North telescope to measure a spectroscopic redshift of z = 4.56 of one of the lensed galaxies. These data are used to refine the lens model of SDSS J2222+2745, compute the time delay and magnifications of the lensed quasar images, and reconstruct the source image of the quasar host and a lensed galaxy at z = 2.3. This galaxy also appears in absorption in our Gemini spectra of the lensed quasar, at a projected distance of 34 kpc. Our model is in agreement with the recent time delay measurements of Dahle et al., who found τ {sub AB} = 47.7 ± 6.0 days and τ {sub AC} = −722 ± 24 days. We use the observed time delays to further constrain the model, and find that the model-predicted time delays of the three faint images of the quasar are τ {sub AD} = 502 ± 68 days, τ {sub AE} = 611 ± 75 days, and τ {sub AF} = 415 ± 72 days. We have initiated a follow-up campaign to measure these time delays with Gemini North. Finally, we present initial results from an X-ray monitoring program with Swift , indicating the presence of hard X-ray emission from the lensed quasar, as well as extended X-ray emission from the cluster itself, which is consistent with the lensing mass measurement and the cluster velocity dispersion.

  7. Efficacy of detergent and water versus bleach for disinfection of direct contact ophthalmic lenses.

    Science.gov (United States)

    Abbey, Ashkan M; Gregori, Ninel Z; Surapaneni, Krishna; Miller, Darlene

    2014-06-01

    Although manufacturers recommend cleaning ophthalmic lenses with detergent and water and then with a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus that of bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses. Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus and 2 viral strains (adenovirus and herpes simplex virus [HSV] type-1) were individually inoculated onto 20 gonioscopy and laser lenses. The lenses were washed with detergent and water and then disinfected with 10% bleach. All the lenses were cultured after inoculation, after washing with detergent and water, and after disinfecting with the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks, and viral cultures were observed for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR). All 20 lenses inoculated with S. epidermidis, C. straitum, adenovirus, and HSV-1 showed growth after inoculation but no growth after washing with detergent/water and after disinfecting with the bleach. All lenses showed positive HSV and adenovirus PCR results after inoculation and negative PCR results after washing with detergent/water and after disinfecting with bleach. All methicillin-resistant S. aureus-contaminated lenses showed growth after inoculation and no growth after washing with detergent and water. However, 1 lens showed positive growth after disinfecting with bleach. Cleaning with detergent and water seemed to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage.

  8. Modern scleral lenses part I: clinical features.

    Science.gov (United States)

    Visser, Esther-Simone; Visser, Rients; van Lier, Henk J J; Otten, Henny M

    2007-01-01

    To evaluate the indications for modern scleral lenses and their clinical performance in patients who were fitted with scleral lenses at the authors' practices. In this cross-sectional survey, all the necessary data were obtained at the first follow-up visit during the 5-month study period. There were four types of scleral lenses: spherical, front-surface toric, back-surface toric, and bitoric. The preformed scleral lens fitting technique developed at Visser Contact Lens Practice was used in all patients. The lenses were cut by precise Sub Micron Lathing from a Boston Equalens II blank at Procornea. Visual acuity and slitlamp findings were recorded. A specially designed classification for scleral lens fitting was used to investigate clinical performance. The largest proportion of the 178 patients (284 eyes) were diagnosed with keratoconus (143 [50.4%] eyes) followed by postpenetrating keratoplasty (56 [19.7%] eyes). The remaining diagnoses were irregular astigmatism, keratitis sicca, corneal dystrophy, and multiple diagnoses. The ratio of spherical to back-surface toric designs was 1:1.1. Clinical examination showed sharp increases in visual acuity (median increase, 0.45) and safe physiologic responses of the anterior eye. All the patients could continue to wear scleral lenses, with 79.2% with the same lens parameters. Several types of corneal abnormality were managed successfully with modern scleral lenses. The main indication was optical correction of an irregular corneal surface. Satisfactory clinical performance meant that all the patients could continue to wear their scleral lenses.

  9. Galaxy bias from galaxy-galaxy lensing in the DES Science Verification Data

    Energy Technology Data Exchange (ETDEWEB)

    Prat, J.; et al.

    2016-09-26

    We present a measurement of galaxy-galaxy lensing around a magnitude-limited ($i_{AB} < 22.5$) sample of galaxies selected from the Dark Energy Survey Science Verification (DES-SV) data. We split these lenses into three photometric-redshift bins from 0.2 to 0.8, and determine the product of the galaxy bias $b$ and cross-correlation coefficient between the galaxy and dark matter overdensity fields $r$ in each bin, using scales above 4 Mpc/$h$ comoving, where we find the linear bias model to be valid given our current uncertainties. We compare our galaxy bias results from galaxy-galaxy lensing with those obtained from galaxy clustering (Crocce et al. 2016) and CMB lensing (Giannantonio et al. 2016) for the same sample of galaxies, and find our measurements to be in good agreement with those in Crocce et al. (2016), while, in the lowest redshift bin ($z\\sim0.3$), they show some tension with the findings in Giannantonio et al. (2016). Our results are found to be rather insensitive to a large range of systematic effects. We measure $b\\cdot r$ to be $0.87\\pm 0.11$, $1.12 \\pm 0.16$ and $1.24\\pm 0.23$, respectively for the three redshift bins of width $\\Delta z = 0.2$ in the range $0.2strong evidence for a cross-correlation parameter significantly below one in this galaxy sample, except possibly at the lowest redshift bin ($z\\sim 0.3$), where we find $r = 0.71 \\pm 0.11$ when using TPZ, and $0.83 \\pm 0.12$ with BPZ, assuming the difference between the results from the two probes can be solely attributed to the cross-correlation parameter.

  10. Modern scleral lenses: Mini versus large.

    Science.gov (United States)

    Fadel, Daddi

    2017-08-01

    The evolution of scleral lenses has led to new formulations of scleral fitting concepts and designs. The diameters of modern scleral lenses have been overhauled too and they are smaller comparing to the original ones. Nowadays, prescription of mini-sclerals supposedly seems in major extension and it appears indeed the necessity of some practitioner to differentiate the smaller mini-scleral lenses from larger mini-scleral lenses empathizing that they are the "smaller" ones. Therefore, it is maybe, necessary a definition of mini-scleral lenses referring to the landing zone width in relation to the horizontal visible iris diameter (HVID) and the limbus extension. The choice of the total diameter is crucial for a successful fitting and it depends majorly on patient's topographic patterns and anatomic factors. However, there are other important criteria for the selection of the scleral lens diameter based on oxygen supply, bubbles formation, mechanical stress on a toric sclera, ocular surface disease protection, entity of the vault over the cornea and distribution of the lens weight on the sclera. The advantages of mini-scleral lenses are various nonetheless in some cases large lenses are necessary. This paper presents a review of the benefits and disadvantages of both mini and large scleral lenses analyzing the conditions in which it may be better to prefer one diameter to another. A suggestion may be that to start fitting the smallest lens as possible, depending on the dimension of HVID and limbus width and consider larger lenses only when issues occur. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  11. Efectividad de los lentes fáquicos Artisan en la corrección de la alta miopía Effectiveness of Artisan phakic lenses in the correction of high myopia

    Directory of Open Access Journals (Sweden)

    Yanele Ruiz Rodríguez

    2010-12-01

    Full Text Available OBJETIVO: Determinar la efectividad de los lentes intraoculares fáquicos Artisan en la corrección de la alta miopía en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer" en el período de enero del 2006 a enero del 2009. MÉTODOS: Se realizó un estudio prospectivo, descriptivo. El universo estuvo constituido por el total de ojos (120 a los cuales se les implantó estos lentes. RESULTADOS: Se encontró un componente esférico de 0,5, no astigmatismo inducido y una mejoría de la agudeza visual corregida de 0,9. No se presentaron complicaciones transoperatorias y entre las posoperatorias mediatas predominó la iritis o uveítis (3,4 % así como la atrofia iridiana (5 % entre las tardías. CONCLUSIONES: Los resultados refractivos fueron favorables. Predominaron los pacientes sin complicaciones.OBJECTIVE: To determine the effectiveness of Artisan phakic intraocular lenses in correcting high myopia at "Ramón Pando Ferrer" Cuban Institute of Ophthalmology in January 2006 to January 2009 period. METHODS: A prospective descriptive study was made in which the universe of study was 120 eyes implanted with this type of lenses. RESULTS: Spheral component of 0.5; the induced astigmatism was not found and the corrected visual acuity improvement was 0.9. There were no transoperative complications; the predominant postoperative mediate complications were iritis or uveitis (3.4 % and iridic atrophy (5 % prevailed in the late ones. CONCLUSIONS: The refractive results were favourable. The uncomplicated patients predominated.

  12. Observation of strong magnetic effects in visible-infrared sum frequency generation from magnetic structures

    NARCIS (Netherlands)

    Kirilyuk, A.; Knippels, G.M.H.; van der Meer, A. F. G.; Renard, S.; Rasing, T.; Heskamp, I. R.; Lodder, J. C.

    2000-01-01

    We have observed very strong magnetization-induced changes of the infrared-visible sum-frequency generation (SFG) intensity from thin magnetic films using a free electron laser as a tunable infrared source. With the help of a magnetic grating a clear resonance is observed due to the excitation of

  13. Flavor changing strong interaction effects on top quark physics at the CERN LHC

    International Nuclear Information System (INIS)

    Ferreira, P.M.; Santos, R.; Oliveira, O.

    2006-01-01

    We perform a model independent analysis of the flavor changing strong interaction vertices relevant to the LHC. In particular, the contribution of dimension six operators to single top production in various production processes is discussed, together with possible hints for identifying signals and setting bounds on physics beyond the standard model

  14. Detecting Gravitational Lensing of the Cosmic Microwave Background by Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Eric Jones [Univ. of Chicago, IL (United States)

    2014-08-01

    Clusters of galaxies gravitationally lens the Cosmic Microwave Background (CMB) leading to a distinct signal in the CMB on arcminute scales. Measurement of the cluster lensing effect offers the exciting possibility of constraining the masses of galaxy clusters using CMB data alone. Improved constraints on cluster masses are in turn essential to the use of clusters as cosmological probes: uncertainties in cluster masses are currently the dominant systematic affecting cluster abundance constraints on cosmology. To date, however, the CMB cluster lensing signal remains undetected because of its small magnitude and angular size. In this thesis, we develop a maximum likelihood approach to extracting the signal from CMB temperature data. We validate the technique by applying it to mock data designed to replicate as closely as possible real data from the South Pole Telescope’s (SPT) Sunyaev-Zel’dovich (SZ) survey: the effects of the SPT beam, transfer function, instrumental noise and cluster selection are incorporated. We consider the effects of foreground emission on the analysis and show that uncertainty in amount of foreground lensing results in a small systematic error on the lensing constraints. Additionally, we show that if unaccounted for, the SZ effect leads to unacceptably large biases on the lensing constraints and develop an approach for removing SZ contamination. The results of the mock analysis presented here suggest that a 4σ first detection of the cluster lensing effect can be achieved with current SPT-SZ data.

  15. 'Colored' and Decorative Contact Lenses: A Prescription Is a Must

    Science.gov (United States)

    ... these looks with decorative contact lenses (sometimes called “fashion,” “costume,” or “colored” contact lenses). These lenses don’ ... Wear Decorative or “Colored” Contact Lenses An entertainment industry artist from American Horror Story and the FDA ...

  16. A Measurement of CMB Cluster Lensing with SPT and DES Year 1 Data

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, E.J.; et al.

    2017-08-03

    Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev-Zel'dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. We detect lensing of the CMB by the galaxy clusters at 6.5$\\sigma$ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly $20\\%$ precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentering.

  17. Nanofocusing refractive X-ray lenses

    International Nuclear Information System (INIS)

    Boye, Pit

    2010-01-01

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  18. Nanofocusing refractive X-ray lenses

    Energy Technology Data Exchange (ETDEWEB)

    Boye, Pit

    2010-02-05

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  19. Thin Film Coating Technology For Ophthalmic Lenses

    Science.gov (United States)

    Guenther, K. H.

    1986-05-01

    Coating of ophthalmic lenses is an application of high-vacuum coating technology which must satisfy not only physical and technical requirements but also customer demands with respect to aesthetics, color fidelity, and exchangeability of coated ophthalmic lenses. Because this application caters specifically to the consumer market, ophthalmic lenses are subject to certain fashion trends which frequently require quick adaptation of the coating technique. The state-of-the-art of ophthalmic lens coating is reviewed in this paper, with particular emphasis on the durability requirements in daily use by untrained consumers as well as on the applicable testing methods.

  20. The massive galaxy cluster XMMU J1230.3+1339 at z ˜ 1: colour-magnitude relation, Butcher-Oemler effect, X-ray and weak lensing mass estimates

    Science.gov (United States)

    Lerchster, M.; Seitz, S.; Brimioulle, F.; Fassbender, R.; Rovilos, M.; Böhringer, H.; Pierini, D.; Kilbinger, M.; Finoguenov, A.; Quintana, H.; Bender, R.

    2011-03-01

    We present results from the multiwavelength study of XMMU J1230.3+1339 at z˜ 1. We analyse deep multiband wide-field images from the Large Binocular Telescope (LBT), multi-object spectroscopy observations from VLT, as well as space-based serendipitous observations, from the GALEX and Chandra X-ray observatories. We apply a Bayesian photometric redshift code to derive the redshifts using the far-UV (FUV), near-UV (NUV) and the deep U, B, V, r, i, z data. We make further use of spectroscopic data from FORS2 to calibrate our photometric redshifts, and investigate the photometric and spectral properties of the early-type galaxies. We achieve an accuracy of ▵z/(1 +z)= 0.07 (0.04) and the fraction of catastrophic outliers is η= 13 (0) per cent, when using all (secure) spectroscopic data, respectively. The i-z against z colour-magnitude relation of the photo-z members shows a tight red sequence with a zero-point of 0.935 mag, and slope equal to -0.027. We observe evidence for a truncation at the faint end of the red-cluster-sequence and the Butcher-Oemler effect, finding a fraction of blue galaxies fb≈ 0.5. Further, we conduct a weak lensing analysis of the deep 26 × 26 arcmin r-band LBC image. The observed shear is fitted with a Single-Isothermal-Sphere and a Navarro-Frenk-White model to obtain the velocity dispersion and the model parameters, respectively. Our best-fitting values are, for the velocity dispersion σSIS= 1308 ± 284 km s-1, concentration parameter c= 4.0+14-2 and scale radius rs= 345+50-57 kpc. From a 38 ks Chandra X-ray observation we obtain an independent estimate of the cluster mass. In addition, we create a signal-to-noise ratio (S/N) map for the detection of the matter mass distribution of the cluster using the mass-aperture technique. We find excellent agreement of the mass concentration identified with weak lensing and the X-ray surface brightness. Combining our mass estimates from the kinematic, X-ray and weak lensing analyses we obtain a

  1. Mesh-free free-form lensing - I. Methodology and application to mass reconstruction

    Science.gov (United States)

    Merten, Julian

    2016-09-01

    Many applications and algorithms in the field of gravitational lensing make use of meshes with a finite number of nodes to analyse and manipulate data. Specific examples in lensing are astronomical CCD images in general, the reconstruction of density distributions from lensing data, lens-source plane mapping or the characterization and interpolation of a point spread function. We present a numerical framework to interpolate and differentiate in the mesh-free domain, defined by nodes with coordinates that follow no regular pattern. The framework is based on radial basis functions (RBFs) to smoothly represent data around the nodes. We demonstrate the performance of Gaussian RBF-based, mesh-free interpolation and differentiation, which reaches the sub-percent level in both cases. We use our newly developed framework to translate ideas of free-form mass reconstruction from lensing on to the mesh-free domain. By reconstructing a simulated mock lens we find that strong-lensing only reconstructions achieve <10 per cent accuracy in the areas where these constraints are available but provide poorer results when departing from these regions. Weak-lensing only reconstructions give <10 per cent accuracy outside the strong-lensing regime, but cannot resolve the inner core structure of the lens. Once both regimes are combined, accurate reconstructions can be achieved over the full field of view. The reconstruction of a simulated lens, using constraints that mimics real observations, yields accurate results in terms of surface-mass density, Navarro-Frenk-White profile (NFW) parameters, Einstein radius and magnification map recovery, encouraging the application of this method to real data.

  2. A search for z= 7.3 Lyα emitters behind gravitationally lensing clusters

    Science.gov (United States)

    Ota, Kazuaki; Richard, Johan; Iye, Masanori; Shibuya, Takatoshi; Egami, Eiichi; Kashikawa, Nobunari

    2012-07-01

    We searched for z= 7.3 Lyα emitters (LAEs) behind two gravitationally lensing clusters, Abell 2390 and CL 0024, using the Subaru Telescope Suprime-Cam and a narrow-band filter NB1006 (λc˜ 1005 nm and full width at half-maximum of about 21 nm). The combination of the fully depleted CCDs of the Suprime-Cam, sensitive to z˜ 7 Lyα emission at ˜ 1 μm, and the magnification by the lensing clusters can be potentially a powerful tool to detect faint distant LAEs. Using the NB1006 and deep optical to mid-infrared images of the clusters taken with the Hubble Space Telescope and Spitzer Space Telescope, we investigated if there exist objects consistent with the colour of z= 7.3 LAEs behind the clusters. We could not detect any LAEs to the unlensed Lyα line flux limit of FLyα≃ 6.9 × 10-18 erg s-1 cm-2. Using several z=7 Lyα luminosity functions (LFs) from the literature, we estimated and compared the expected detection numbers of z˜ 7$ LAEs in lensing and blank field surveys in the case of using an 8-m class ground-based telescope. Given the steep bright-end slope of the LFs, when the detector field of view (FOV) is comparable to the angular extent of a massive lensing cluster, imaging cluster(s) is (are) more efficient in detecting z˜ 7 LAEs than imaging a blank field. However, the gain is expected to be modest, a factor of 2 at most and likely much less depending on the adopted LFs. The main advantage of lensing survey, therefore, remains the gain in depth and not necessarily in detection efficiency. For much larger detectors, the lensing effect becomes negligible and the efficiency of LAE detection is proportional to the instrumental FOV. We also investigated the NB1006 images of the three z˜ 7 z-dropout galaxy candidates previously detected in Abell 2390 and found that none of them is detected in NB1006. Two of them are consistent with the predictions from previous studies that they would be at lower redshifts. The other one has a photometric redshift of z

  3. On Using a Space Telescope to Detect Weak-lensing Shear

    Science.gov (United States)

    Tung, Nathan; Wright, Edward

    2017-11-01

    Ignoring redshift dependence, the statistical performance of a weak-lensing survey is set by two numbers: the effective shape noise of the sources, which includes the intrinsic ellipticity dispersion and the measurement noise, and the density of sources that are useful for weak-lensing measurements. In this paper, we provide some general guidance for weak-lensing shear measurements from a “generic” space telescope by looking for the optimum wavelength bands to maximize the galaxy flux signal-to-noise ratio (S/N) and minimize ellipticity measurement error. We also calculate an effective galaxy number per square degree across different wavelength bands, taking into account the density of sources that are useful for weak-lensing measurements and the effective shape noise of sources. Galaxy data collected from the ultra-deep UltraVISTA Ks-selected and R-selected photometric catalogs (Muzzin et al. 2013) are fitted to radially symmetric Sérsic galaxy light profiles. The Sérsic galaxy profiles are then stretched to impose an artificial weak-lensing shear, and then convolved with a pure Airy Disk PSF to simulate imaging of weak gravitationally lensed galaxies from a hypothetical diffraction-limited space telescope. For our model calculations and sets of galaxies, our results show that the peak in the average galaxy flux S/N, the minimum average ellipticity measurement error, and the highest effective galaxy number counts all lie around the K-band near 2.2 μm.

  4. Interference effects at photoionization of Rydberg atoms by a strong electromagnetic field

    International Nuclear Information System (INIS)

    Movsesyan, A.M.; Fedorov, M.V.

    1989-01-01

    The photoionization of Rydberg atoms in a strong electromagnetic field is considered. Degeneration of the levels with respect to the orbital moment, their Stark splitting and the possibility of resonant interaction with levels of lower energy are taken into account. The complex quasi-energies of the system, photoelectron spectrum in the limit of an infinite duration of interaction and the time dependence of the total ionization probability are found. It is shown that a narrowing of the quasi-energy levels occurs in a strong field. Against a background of the quasi- continuum the quasi-energy spectrum consists of more or less narrow levels. In this case the photoelectron spectrum acquires a multi-peak form. With increasing field strength the height of the peaks increases, whereas their width decreases. The ionization rate decreases with increasing field strength. The presence of a quasi-continuum is the cause of the partially non-exponential nature of the atomic disintegration

  5. Detection of brown dwarfs by the micro-lensing of unresolved stars

    CERN Document Server

    Baillon, Paul; Giraud-Héraud, Yannick; Kaplan, J; Baillon, Paul; Bouquet, Alain; Giraud-Héraud, Yannick; Kaplan, Jean

    1993-01-01

    The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the photon flux from a galaxy is measured with a good precision, it is not necessary to resolve the stars and besides more events could be observed.

  6. Glutathione Preservation during Storage of Rat Lenses in Optisol-GS and Castor Oil

    DEFF Research Database (Denmark)

    Holm, Thomas; Brøgger-Jensen, Martin Rocho; Johnson, Leif

    2013-01-01

    Glutathione concentration in the lens decreases in aging and cataractous lenses, providing a marker for tissue condition. Experimental procedures requiring unfrozen lenses from donor banks rely on transportation in storage medium, affecting lens homeostasis and alterations in glutathione levels. ....... The aim of the study was to examine the effects of Optisol-GS and castor oil on lens condition, determined from their ability to maintain glutathione concentrations....

  7. Constraining the neutrino emission of gravitationally lensed Flat-Spectrum Radio Quasars with ANTARES data

    OpenAIRE

    Adrian-Martinez, S.; Albert, A.; Andre, M.; Anton, G.; Ardid, M.; Aubert, J. J.; Baret, B.; Barrios-Marti, J.; Basa, S.; Bertin, V.; Biagii, S.; Bogazzi, C.; Bormuth, R.; Bou-Cabo, M.; Bouwhuis, M. C.

    2014-01-01

    This paper proposes to exploit gravitational lensing effects to improve the sensitivity of neutrino telescopes to the intrinsic neutrino emission of distant blazar populations. This strategy is illustrated with a search for cosmic neutrinos in the direction of four distant and gravitationally lensed Flat-Spectrum Radio Quasars. The magnification factor is estimated for each system assuming a singular isothermal profile for the lens. Based on data collected from 2007 to 2012 by the ANTARES neu...

  8. Carrier envelope phase effects in molecular dissociation by few-cycle strong laser fields

    Energy Technology Data Exchange (ETDEWEB)

    Dimitriou, K I [Hellenic Army Academy, Department of Natural Science and Applications, Vari (Greece); Constantoudis, V [Institute of Microelectronics, NCSR ' Demokritos' , Athens (Greece); Mercouris, Th [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens (Greece); Nicolaides, C A, E-mail: dimi@eie.g [Physics Department, National Technical University, Athens (Greece)

    2009-11-01

    Multiphoton molecular dissociation produced by few-cycle strong laser fields of mid-infrared wave lengths is studied theoretically. The dependence of the carrier envelope phase (CEP) on the photodissociation dynamics is investigated using both quantum and classical nonperturbative approaches. Our results show that dissociation is affected by the changes of the CEP. A detailed analysis shows that this dependence is sensitive to the duration and to the shape of the pulse.

  9. Effects of strong cathodic polarization of the Ni-YSZ interface

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Chen, Ming; Jacobsen, Torben

    2016-01-01

    Long-term strong cathodic polarization experiments of down to -2.4 V vs. E°(O2) of the Ni-YSZ interface were performed at 900°C in 97% H2/3% H2O on model electrodes. The Ni-YSZ interface underwent extensive changes and a large affected volume with a complex microstructure and phase distribution r...

  10. Users' and nonusers' evaluations of the CPF 550 lenses.

    Science.gov (United States)

    Morrissette, D L; Mehr, E B; Keswick, C W; Lee, P N

    1984-11-01

    Thirty-six subjects completed questionnaires on their experiences wearing the CPF 550 lenses. Twenty-six subjects [21 with retinitis pigmentosa (RP)] were users of the 550's and 10 subjects (6 with RP) were nonusers who had rejected the 550's after a trial period. Subjects were asked about such factors as effects on adaptation time, ocular comfort, visual functioning, acceptability of tint strength in various lighting conditions, cosmetic appearance, effects of weather, and replacement intent. Users reported reduced adaptation time in changes of illumination, increased ocular comfort, improved visual functioning with the exception of poor color discrimination, and cosmetic acceptability. Satisfaction with tint strength varied with degree of illumination; usefulness in different types of weather also varied depending on the condition. Nonusers' responses were mixed; they were less likely to report improvements with the CPF 550 lenses compared to the users' group.

  11. An integral-field spectroscopic strong lens survey

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Adam S [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. MS-20, Cambridge, MA 02138 (United States); Burles, Scott [Department of Physics and Kavli Institute, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)

    2007-12-15

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction.

  12. An integral-field spectroscopic strong lens survey

    International Nuclear Information System (INIS)

    Bolton, Adam S; Burles, Scott

    2007-01-01

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction

  13. Characterisation of adaptive fluidic silicone membrane lenses

    CSIR Research Space (South Africa)

    Schneider, F

    2009-09-01

    Full Text Available In this paper the auhtors compare the performance and optical quality of two types of adaptive fluidic silicone-membrane lenses. The membranes feature either a homogeneous thickness, or they are shaped resulting in an inhomogeneous cross...

  14. Disposable contact lenses in penetrating keratoplasty.

    Science.gov (United States)

    Arora, R; Gupta, S; Taneja, M; Raina, U K; Mehta, D K

    2000-07-01

    To evaluate the therapeutic efficacy of disposable contact lenses in management of complications after keratoplasty. Twenty-eight patients with various post keratoplasty complications were fit with disposable contact lenses (45% Vifilcon A and 55% water content). Indications for lens use included persistent epithelial defects, wound leak, graft edema, dry eye and protection of normal corneal epithelium. Success was obtained with the therapeutic use of disposable lenses in 20 of the 28 cases. The best results were seen in maintenance and restoration of healthy ocular surface and small wound leaks. Stromal graft edema with no epithelial involvement was the major area of therapeutic failure. Disposable contact lenses are an attractive low cost option in the management of complications after keratoplasty. They are particularly useful in maintaining a healthy ocular surface, providing symptomatic relief and avoiding resurgery in patients with small wound leaks.

  15. Gravitational Lensing Mass Mapping with Gaussian Processes

    Science.gov (United States)

    Schneider, Michael; Ng, Karen; Dawson, William; Marshall, Phil; Meyers, Joshua; Bard, Deborah

    2018-01-01

    We infer gravitational lensing shear and convergence fields from galaxy ellipticity catalogs under a Gaussian Process prior for the lensing potential. We demonstrate the performance of our algorithm with simulated Gaussian-distributed cosmological lensing shear maps and a reconstruction of the mass distribution of the merging galaxy cluster Abell 781 using galaxy ellipticities measured with the Deep Lens Survey. Given interim posterior samples of lensing shear or convergence fields on the sky, we describe an algorithm to infer cosmological parameters via lens field marginalization. In the most general formulation of our algorithm we make no assumptions about weak shear orGaussian-distributed shape noise or shears. Because we require solutions and matrix determinants of a linear system of dimension that scales with the number of galaxies, we present computational performance metrics with approximate algorithms that introduce sparsity in the Gaussian Process kernel.

  16. A dark matter component decaying after recombination: lensing constraints with Planck data

    Directory of Open Access Journals (Sweden)

    Chudaykin Anton

    2016-01-01

    Full Text Available It was recently proposed [1] that the model with a fraction of decaying cold dark matter is able to reconcile measurements in high redshift (CMB and low redshift (probes of cluster abundance and the Hubble constant. We check this statement employing the full likelihood of CMB Planck data. We find that the lensing effect calculated from anisotropy spectra measured by Planck imposes the strong constraint on the fraction of unstable dark matter as F < 8% (2σ. However, combining the CMB data with conflicting measurements in low redshift we obtain that the model with F ≈ 2 − 5% improves the goodness-of-fit by 1.5 − 2σ depending on As and τ priors in comparison with the concordance ΛCDM model.

  17. Effect of a strong, DC-induced magnetic field on circadian singing activity of the house cricket (orthoptera:gryllidae)

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, K.C.; Bitzer, R.J.; Galliart, L. [Iowa State Univ., Ames, IA (United States)] [and others

    1995-05-01

    We investigated the effect of a strong, DC-induced electromagnetic field (EMF) on the circadian singing activity of the house cricket, Acheta domesticus (L.). Groups of 10 crickets were exposed to strong, DC-induced EMFs under two light regimes, 12:12 (L:D) h and 0:24 (L:D) h. Exposure to the strong EMF resulted in an increase in mean time per hour during which one or more crickets were singing and in number of crickets singing per hour. Correcting for phase shift during O:24 (L:D) h, the daily pattern of singing was apparently unaffected by any treatment. The greatest percentage of singing and number of crickets singing per hour occurred during actual or expected scotophase. This is the first report of an increase in insect activity during exposure to a strong DC-induced EMF.

  18. Some aspects of powerful lasers and aspheric lenses design

    International Nuclear Information System (INIS)

    Metz, Jean de

    1976-01-01

    Gigawatt power glass lasers are described. Geometrical, interferometric, coherence and focusing aspects of the beam are measured. Design of disc amplifier is shown with high gain glass. Aspheric lenses are designed and tested for focussing these beams. Experiments of multi-breakdown in gas are done. We get fusion in plasma made by second harmonic frequency of our 1.06 μ beam. Effect of self-focussing on laser beam quality is studied. (author) [fr

  19. Absorption of ammonia by high water content hydrogel lenses: an inexpensive method of analysis.

    Science.gov (United States)

    LaMotte, J; Smith, G; Chang-Smith, A

    1995-09-01

    Few studies have been done on the absorption and release of chemical vapors by high water content hydrogel lenses. In this study we investigated the absorption of ammonia vapors by this type of contact lens (CL). Ten high water content hydrogel lenses were exposed to vapor generated in a cuvette by 1 drop of aqueous ammonia. The contact lens was transferred to a 0.9% saline solution containing a colorometric indicator for ammonia and the amount of ammonia released into the saline was measured. We found that significant quantities of ammonia were absorbed into the lenses and the relation between average concentration of ammonia vapor and amount absorbed per contact lens was nearly linear from 50 parts per million (ppm) to 250 ppm ammonia vapor. For concentrations greater than 250 ppm there appears to be a saturation effect. Our findings indicate that high water contact lenses will absorb ammonia and release it into a solution similar to tears.

  20. Thirty Meter Telescopes and Gravitational Lensing

    OpenAIRE

    Carlberg, R. G.

    2004-01-01

    Diffraction limited 30m class telescopes will play an important role in gravitational lensing studies, coming online in approximately 2015. As imaging telescopes they will complement the ~6m JWST, probing to smaller angular scales in greatly magnified objects near critical lines and for measuring shear of objects below the JWST angular scale, such as luminous super-star clusters at high redshift. The high source density will allow more detailed mass mapping in the weak lensing regime and will...

  1. Comments on the Gravitational lensing Magnification

    OpenAIRE

    Takashi, HAMANA; Astronomical Institute, Tohoku University

    1998-01-01

    We rederive a relation between gravitational lensing magnification relative to the standard Friedmann distance and one relative to the Dyer-Roeder distance by investigating the null geodesic deviation equation. We show that the relation comes from a natural consequence of the definition of the lensing magnification matrices and is not based on the averaging of the magnifications, which has conventionally been used to derive it. We therefore conclude that the relation is true for each individu...

  2. Comments on the gravitational lensing magnification

    OpenAIRE

    Hamana, Takashi

    1998-01-01

    We rederive a relation between gravitational lensing magnification relative to the standard Friedmann distance and one relative to the Dyer-Roeder distance by investigating the null geodesic deviation equation. We show that the relation comes from a natural consequence of the definition of the lensing magnification matrices and is not based on the averaging of the magnifications, which has conventionally been used to derive it. We therefore conclude that the relation is true for each individu...

  3. Planck 2015 results: XV. Gravitational lensing

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40σ), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator, we detect lensing at a significance of 5σ. We......-scale temperature anisotropies, detecting a cross-correlation at the 3σ level, as expected because of dark energy in the concordance ΛCDM model....

  4. Revised Unfilling Procedure for Solid Lithium Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Leveling, A.; /Fermilab

    2003-06-03

    A procedure for unfilling used lithium lenses to has been described in Pbar Note 664. To date, the procedure has been used to disassemble lenses 20, 21, 17, 18, and 16. As a result of this work, some parts of the original procedure were found to be time consuming and ineffective. Modifications to the original procedure have been made to streamline the process and are discussed in this note. The revised procedure is included in this note.

  5. THE THIRD GRAVITATIONAL LENSING ACCURACY TESTING (GREAT3) CHALLENGE HANDBOOK

    International Nuclear Information System (INIS)

    Mandelbaum, Rachel; Kannawadi, Arun; Simet, Melanie; Rowe, Barnaby; Kacprzak, Tomasz; Bosch, James; Miyatake, Hironao; Chang, Chihway; Gill, Mandeep; Courbin, Frederic; Jarvis, Mike; Armstrong, Bob; Lackner, Claire; Leauthaud, Alexie; Nakajima, Reiko; Rhodes, Jason; Zuntz, Joe; Bridle, Sarah; Coupon, Jean; Dietrich, Jörg P.

    2014-01-01

    The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation of very small galaxy shape distortions, in the presence of far larger intrinsic galaxy shapes and distortions due to the blurring kernel caused by the atmosphere, telescope optics, and instrumental effects. The GREAT3 challenge is posed to the astronomy, machine learning, and statistics communities, and includes tests of three specific effects that are of immediate relevance to upcoming weak lensing surveys, two of which have never been tested in a community challenge before. These effects include many novel aspects including realistically complex galaxy models based on high-resolution imaging from space; a spatially varying, physically motivated blurring kernel; and a combination of multiple different exposures. To facilitate entry by people new to the field, and for use as a diagnostic tool, the simulation software for the challenge is publicly available, though the exact parameters used for the challenge are blinded. Sample scripts to analyze the challenge data using existing methods will also be provided. See http://great3challenge.info and http://great3.projects.phys.ucl.ac.uk/leaderboard/ for more information

  6. An experimental study of nanoparticle focusing with aerodynamic lenses

    Science.gov (United States)

    Wang, Xiaoliang; McMurry, Peter H.

    2006-12-01

    High sampling efficiencies of analyte ions, molecules or particles are needed to maximize the sensitivity of mass spectrometers. "Ion funnels", which utilize electrodynamic focusing, have been shown to effectively focus ions with mass-to-charge ratio (m/z) ranging from ~100 to 5000. Focusing efficiencies of ion funnels drop for higher m/z values because very high voltages are needed to overcome the particle inertia. Conventional "aerodynamic lenses" utilize inertia to focus down to 25 nm in diameter (~5 MDa); to date, Brownian diffusion has prevented the effective focusing of particles smaller than this. We recently reported a design procedure that should, in principle, extend focusing with aerodynamic lenses to particles as small as 3 nm (~10 kDa), thereby bridging the gap between the ion funnel and the conventional aerodynamic lenses. In this paper, we report for the first time experimental results for the performance of these new "nanolenses". Measurements were done using spherical oil droplets, proteins, and sodium chloride particles ranging in size from 3 to 30 nm diameter. We found that particle transport efficiencies from atmospheric pressure to vacuum through the aerodynamic lens system were greater than 80% for 10-30 nm particles, and greater than 50% for a ~3.8 nm protein (Lysozyme from chicken egg white, molecular weight 14.3 kDa). Particle beam diameters were about a factor of two greater than predicted by our numerical simulations, but provide clear evidence that the nanolenses effectively focus all three particle types.

  7. Predicting gravitational lensing by stellar remnants

    Science.gov (United States)

    Harding, Alexander J.; Stefano, R. Di; Lépine, S.; Urama, J.; Pham, D.; Baker, C.

    2018-03-01

    Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this paper, we describe the prospects for predicting lensing events generated by the local population of compact objects, consisting of 250 neutron stars, five black holes, and ≈35 000 white dwarfs. By focusing on a population of nearby compact objects with measured proper motions and known distances from us, we can measure their masses by studying the characteristics of any lensing event they generate. Here, we concentrate on shifts in the position of a background source due to lensing by a foreground compact object. With Hubble Space Telescope, JWST, and Gaia, measurable centroid shifts caused by lensing are relatively frequent occurrences. We find that 30-50 detectable events per decade are expected for white dwarfs. Because relatively few neutron stars and black holes have measured distances and proper motions, it is more difficult to compute realistic rates for them. However, we show that at least one isolated neutron star has likely produced detectable events during the past several decades. This work is particularly relevant to the upcoming data releases by the Gaia mission and also to data that will be collected by JWST. Monitoring predicted microlensing events will not only help to determine the masses of compact objects, but will also potentially discover dim companions to these stellar remnants, including orbiting exoplanets.

  8. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, D.; Omori, Y.; Benoit-Lévy, A.; Cawthon, R.; Chang, C.; Larsen, P.; Amara, A.; Bacon, D.; Crawford, T. M.; Dodelson, S.; Fosalba, P.; Giannantonio, T.; Holder, G.; Jain, B.; Kacprzak, T.; Lahav, O.; MacCrann, N.; Nicola, A.; Refregier, A.; Sheldon, E.; Story, K. T.; Troxel, M. A.; Vieira, J. D.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Becker, M. R.; Benson, B. A.; Bernstein, G. M.; Bernstein, R. A.; Bleem, L. E.; Bonnett, C.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carlstrom, J. E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reichardt, C. L.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Simard, G.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Wechsler, R. H.; Weller, J.

    2016-03-10

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photometric redshift uncertainty and CMB lensing systematics. Significant intrinsic alignment of galaxy shapes would increase the cross-correlation signal inferred from the data; we calculate a value of $A = 1.08 \\pm 0.36$ for DES$\\times$SPT when we correct the observations with a simple IA model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation, given the size of the statistical uncertainties and the significant impact of systematic errors, particularly IAs. We provide forecasts for the expected signal-to-noise of the combination of the five-year DES survey and SPT-3G.

  9. The effect of regional variation of seismic wave attenuation on the strong ground motion from earthquakes

    International Nuclear Information System (INIS)

    Chung, D.H.; Bernreuter, D.L.

    1981-10-01

    Attenuation is caused by geometric spreading and absorption. Geometric spreading is almost independent of crustal geology and physiographic region, but absorption depends strongly on crustal geology and the state of the earth's upper mantle. Except for very high frequency waves, absorption does not affect ground motion at distances less than about 25 to 50 km. Thus, in the near-field zone, the attenuation in the eastern United States is similar to that in the western United States. Beyond the near field, differences in ground motion can best be accounted for by differences in attenuation caused by differences in absorption. The stress drop of eastern earthquakes may be higher than for western earthquakes of the same seismic moment, which would affect the high-frequency spectral content. But we believe this factor is of much less significance than differences in absorption in explaining the differences in ground motion between the East and the West. The characteristics of strong ground motion in the conterminous United States are discussed in light of these considerations, and estimates are made of the epicentral ground motions in the central and eastern United States. (author)

  10. Efflux and hydrolysis of phosphorylethanolamine and phosphorylcholine in stressed cultured rat lenses.

    Science.gov (United States)

    Jernigan, H M; Desouky, M A; Geller, A M; Blum, P S; Ekambaram, M C

    1993-01-01

    Phosphorylcholine (P-choline), and phosphorylethanolamine (P-ethanolamine) are among the organic phosphate compounds that decrease in concentration in some cataracts and in lenses that have been subjected to cataractogenic osmotic or oxidative stresses. Decreases in the lenticular concentrations of these compounds could be caused by decreased synthesis, increased utilization or hydrolysis, or increased efflux, or by a combination of these mechanisms. To distinguish between these possibilities, the P-choline and P-ethanolamine pools of intact cultured rat lenses were radiolabeled with [3H]choline or [3H]ethanolamine, and the lenses were then subjected to oxidative or osmotic stress. The efflux and hydrolysis of P-[3H]choline and P-[3H]ethanolamine were then followed for up to 48 hr. Osmotic stress induced by incubation with 30 mM xylose caused increased P-choline and P-ethanolamine efflux from the lenses, but had little effect on the rate of hydrolysis of these compounds. For example, xylose-treated lenses lost 26% of their initial P-[3H]ethanolamine content into the medium during a 24 hr incubation, compared with only 6% for control lenses. Oxidative stress from singlet oxygen (generated by rose bengal and light) also increased lenticular P-choline efflux three to four-fold, with minimal effects on hydrolysis, and the increased efflux was accompanied by a decrease in the P-choline concentration. Permeability increases also were observed in lenses oxidatively stressed by H2O2 or by riboflavin and light. These results show that a variety of cataractogenic stresses, both oxidative and osmotic, cause increased permeability of rat lenses to organic phosphate compounds, including P-choline and P-ethanolamine.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Thermal lensing compensation for AIGO high optical power test facility

    International Nuclear Information System (INIS)

    Degallaix, Jerome; Zhao Chunnong; Ju Li; Blair, David

    2004-01-01

    We present finite element modelling of thermal lensing occurring in an interferometer test mass. Our simulations include the thermo-optic effect and mechanical expansion of the optics. For the High Optical Power Test Facility (HOPTF) operated by the Australian International Gravitational Observatory (AIGO), the optical path length measured across the laser beam radius is 45 nm for 1.2 W absorbed power for the input sapphire test mass. The AIGO thermal lens is much stronger than the one in Advanced LIGO and will degrade the interferometer performance. Direct thermal compensation and the use of an external compensation plate were investigated to minimize thermal lensing consequences in the interferometer. For the AIGO situation, a fused silica external plate is the most practical solution to correct thermally induced wavefront distortions. The compensation plate requires lower thermal power than direct compensation and does not increase the test mass temperature

  12. Gravitational Lensing as a Probe of Cold Dark Matter Subhalos

    Directory of Open Access Journals (Sweden)

    Erik Zackrisson

    2010-01-01

    Full Text Available In the cold dark matter scenario, dark matter halos are assembled hierarchically from smaller subunits. Some of these subunits are disrupted during the merging process, whereas others survive temporarily in the form of subhalos. A long-standing problem with this picture is that the number of subhalos predicted by simulations exceeds the number of luminous dwarf galaxies seen in the vicinity of large galaxies like the Milky Way. Many of the subhalos must therefore have remained dark or very faint. If cold dark matter subhalos are as common as predicted, gravitational lensing may in principle offer a promising route to detection. In this paper, we describe the many ways through which lensing by subhalos can manifest itself, and summarize the results from current efforts to constrain the properties of cold dark matter subhalos using such effects.

  13. Dark-Matter in Galaxies from Gravitational Lensing and Stellar Dynamics Studies

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Corbett, IF

    2010-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary methods in the study of the mass distribution of dark matter in galaxies out to redshift of unity. They are particularly powerful in the determination of the total mass and the density profile of mass early-type galaxies on

  14. arXiv Strong reduction of the effective radiation length in an oriented PWO scintillator crystal

    CERN Document Server

    Bandiera, L.; Romagnoni, M.; Argiolas, N.; Bagli, E.; Ballerini, G.; Berra, A.; Brizzolani, C.; Camattari, R.; De Salvador, D.; Haurylavets, V.; Mascagna, V.; Mazzolari, A.; Prest, M.; Soldani, M.; Sytov, A.; Vallazza, E.

    We measured a considerable increase of the emitted radiation by 120 GeV/c electrons in an axially oriented lead tungstate scintillator crystal, if compared to the case in which the sample was not aligned with the beam direction. This enhancement resulted from the interaction of particles with the strong crystalline field. The data collected at the external lines of CERN SPS were critically compared to Monte Carlo simulations based on the Baier Katkov quasiclassical method, highlighting a reduction of the scintillator radiation length by a factor of five in case of beam alignment with the [001] crystal axes. As a consequence, oriented scintillator crystals may be profitably exploited to reduce the amount of material in electromagnetic calorimeters/detectors for fixed-target experiments in high-energy physics, as well as for satellite-borne gamma-telescopes in astrophysics.

  15. Effects of weak and strong localization in tunnel characteristics of contacts on HTSC base

    International Nuclear Information System (INIS)

    Revenko, Yu.V.; Svistunov, V.M.; Grigut', O.V.; Belogolovskij, M.A.; Khachaturov, A.I.

    1992-01-01

    It is found that a phenomena governed by the electronic processes in the disordered surface normal layer of material are observed in the tunnel contatcs bases on metal oxide superconductors of 1-2-3 group. Measured characteristics σ(U)=dI/dU ore determined both by contact's barrier properties and conductivity in the disordered region of metal oxides in the vicinity of a barrier. As regards high-temperature contacts σ(U) value at high temperatures us determined by the Schottky barrier and at low temperatures - by activation processes of charge transfer over strongly localized states in near-the-barrier region of the contact. Crossing over towards logarithmic dependence in the tunnel conductuvity σ(U) of low-Ohmic transitions are attributed to the occurrence of 2D state density conditions in the tunnel surface layers of metal oxides

  16. Electrically controllable ionic polymeric gels as adaptive optical lenses

    Science.gov (United States)

    Salehpoor, Karim; Shahinpoor, Mohsen; Mojarrad, Mehran

    1996-02-01

    Reversible change in optical properties of ionic polymeric gels, 2-acrylamido-2-methylpropane sulfonic acid (PAMPS) and polyacrylic acid plus sodium acrylate cross-linked with bisacrylamide (PAAM), under the effect of an electric field is reported. The shape of a cylindrical piece of the gel, with flat top and bottom surfaces, changed when affected by an electric field. The top surface became curved and the sense of the curvature (whether concave or convex) depended on the polarity of the applied electric field. The curvature of the surface changed from concave to convex and vice versa by changing the polarity of the electric field. By the use of an optical apparatus, focusing capability of the curved surface was verified and the focal length of the deformed gel was measured. The effect of the intensity of the applied electric field on the surface curvature and thus, on the focal length of the gel are tested. Different mechanisms are discussed; either of them or their combination may explain the surface deformation and curvature. Practical difficulties in the test procedure and the future potential of the electrically adaptive and active optical lenses are also discussed. These adaptive lenses may be considered as smart adaptive lenses for contact lens or other optical applications requiring focal point undulation.

  17. Strong control and squeezing effects of radiation states in a slab waveguide sandwiched between two omnidirectional mirrors

    NARCIS (Netherlands)

    van Driel, H.M.; Hoekstra, Hugo; Stoffer, Remco; Yudistira, D.

    The effect of sandwiching a slab waveguide in air between two omnidirectional mirrors on the local density of modes is investigated theoretically. Design aspects of such a structure are considered, and it is shown that the local density of modes other than the slab-guided mode can be strongly

  18. Modeling fine-scale geological heterogeneity-examples of sand lenses in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Comunian, Alessandro; Oriani, Fabio

    2013-01-01

    . However, two-dimensional training images acquired by outcrop mapping are of limited use to generate three-dimensional realizations with MPS. One can use a technique that consists in splitting the 3D domain into a set of slices in various directions that are sequentially simulated and reassembled into a 3D...... on till outcrops producing binary images of geological cross-sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non-stationary patterns on section images...

  19. Image formation in weak gravitational lensing by tidal charged black holes

    International Nuclear Information System (INIS)

    Horvath, Zsolt; Gergely, Laszlo Arpad; Hobill, David

    2010-01-01

    We derive a generic weak lensing equation and apply it for the study of images produced by tidal charged brane black holes. We discuss the similarities and point out the differences with respect to the Schwarzschild black hole weak lensing, to both first- and second-order accuracy, when either the mass or the tidal charge dominates. In the case of mass-dominated weak lensing, we analyze the position of the images, the magnification factors and the flux ratio, as compared to the Schwarzschild lensing. The most striking modification appears in the flux ratio. When the tidal charge represents the dominating lensing effect, the number and orientation of the images with respect to the optical axis resembles the lensing properties of a Schwarzschild geometry, where the sign associated with the mass is opposite to that for the tidal charge. Finally it is found that the ratio of the brightness of the images as a function of image separation in the case of tidal charged black holes obeys a power-law relation significantly different from that of Schwarzschild black holes. This might provide a means for determining the underlying spacetime structure.

  20. Ability of silver-impregnated contact lenses to control microbial growth and colonisation

    Science.gov (United States)

    Willcox, Mark D.P.; Hume, Emma B.H.; Vijay, Ajay K.; Petcavich, Robert

    2010-01-01

    Purpose To examine the ability of silver nano-particles to prevent the growth of Pseudomonas aeruginosa and Staphylococcus aureus in solution or when adsorbed into contact lenses. To examine the ability of silver nano-particles to prevent the growth of Acanthamoeba castellanii. Methods Etafilcon A lenses were soaked in various concentrations of silver nano-particles. Bacterial cells were then exposed to these lenses, and numbers of viable cells on lens surface or in solution compared to etafilcon A lenses not soaked in silver. Acanthamoeba trophozoites were exposed to silver nano-particles and their ability to form tracks was examined. Results Silver nano-particle containing lenses reduced bacterial viability and adhesion. There was a dose-dependent response curve, with 10 ppm or 20 ppm silver showing > 5 log reduction in bacterial viability in solution or on the lens surface. For Acanthamoeba, 20 ppm silver reduced the ability to form tracks by approximately 1 log unit. Conclusions Silver nanoparticles are effective antimicrobial agents, and can reduce the ability of viable bacterial cells to colonise contact lenses once incorporated into the lens.

  1. Survey of strong motion earthquake effects on thermal power plants in California with emphasis on piping systems. Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.D. [Stevenson and Associates, Cleveland, OH (United States)

    1995-11-01

    Volume 2 of the ``Survey of Strong Motion Earthquake Effects on Thermal Power Plants in California with Emphasis on Piping Systems`` contains Appendices which detail the detail design and seismic response of several power plants subjected to strong motion earthquakes. The particular plants considered include the Ormond Beach, Long Beach and Seal Beach, Burbank, El Centro, Glendale, Humboldt Bay, Kem Valley, Pasadena and Valley power plants. Included is a typical power plant piping specification and photographs of typical power plant piping specification and photographs of typical piping and support installations for the plants surveyed. Detailed piping support spacing data are also included.

  2. Photogeneration of neutrino and axions under stimulating effect of strong magnetic field

    CERN Document Server

    Skobelev, V V

    2001-01-01

    The processes of the neutrino and axions photoproduction on the gamma(Ze) -> gamma(nu nu-bar), gamma alpha nuclei, as well as the photon inelastic scattering on the gamma gamma -> gamma(nu nu-bar), gamma alpha photon are considered within the frames of the developed two-dimensional co-variant theory for calculating the matrix of the Feynman diagrams in the strong magnetic field. The contribution of the neutrino radiative photoproduction on the nuclei to the luminosity of the magnetic neutron stars on the early stages of their evolution may compete with the URCA-processes, because the matrix elements in the four-pole diagram depend linearly on the induction of B magnetic field by the B values approx 10 sup 3 -10 sup 4 B sub 0 (B sub 0 = m sub e sup 2 /|e| = 4.41 x 10 sup 1 sup 3 Gs). The evaluation of the axion mass upper boundary, compatible with other independent results, is obtained from the condition of the neutrino luminosity prevailing over the axion one at supposed temperature and magnetic field inducti...

  3. Efficient lensing element for x-rays

    International Nuclear Information System (INIS)

    Ceglio, N.M.; Smith, H.I.

    1977-01-01

    An efficient x-ray lens with an effective speed of order less than approximately f/50 for lambda greater than approximately 10 A x-rays is described. Fabrication of this lensing element appears feasible using existing microfabrication technology. Diffraction and refraction are coupled in a single element to achieve efficient x-ray concentration into a single order focal spot. Diffraction is used to produce efficient ray bending (without absorption) while refraction is used only to provide appropriate phase adjustment among the various diffraction orders to insure what is essentially a single order output. The mechanism for ray bending (diffraction) is decoupled from the absorption mechanism. Refraction is used only to achieve small shifts in phase so that the associated attenuation need not be prohibitive. The x-ray lens might be described as a Blazed Fresnel Phase Plate (BFPP) with a spatially distributed phase shift within each Fresnel zone. The spatial distribution of the phase shifts is chosen to concentrate essentially all of the unabsorbed energy into a single focal spot. The BFPP transforms the incident plane wave into a converging spherical wave having an amplitude modulation which is periodic in r 2 . As a result of the periodic amplitude modulation, the BFPP will diffract energy into foci other than the first order real focus. In cases of small absorption such effects are negligible and practically all the unabsorbed energy is directed into the first order real focus

  4. Bayesian galaxy shape measurement for weak lensing surveys - III. Application to the Canada-France-Hawaii Telescope Lensing Survey

    Science.gov (United States)

    Miller, L.; Heymans, C.; Kitching, T. D.; van Waerbeke, L.; Erben, T.; Hildebrandt, H.; Hoekstra, H.; Mellier, Y.; Rowe, B. T. P.; Coupon, J.; Dietrich, J. P.; Fu, L.; Harnois-Déraps, J.; Hudson, M. J.; Kilbinger, M.; Kuijken, K.; Schrabback, T.; Semboloni, E.; Vafaei, S.; Velander, M.

    2013-03-01

    A likelihood-based method for measuring weak gravitational lensing shear in deep galaxy surveys is described and applied to the Canada-France-Hawaii Telescope (CFHT) Lensing Survey (CFHTLenS). CFHTLenS comprises 154 deg2 of multi-colour optical data from the CFHT Legacy Survey, with lensing measurements being made in the i' band to a depth i'AB noise ratio νSN ≳ 10. The method is based on the lensfit algorithm described in earlier papers, but here we describe a full analysis pipeline that takes into account the properties of real surveys. The method creates pixel-based models of the varying point spread function (PSF) in individual image exposures. It fits PSF-convolved two-component (disc plus bulge) models to measure the ellipticity of each galaxy, with Bayesian marginalization over model nuisance parameters of galaxy position, size, brightness and bulge fraction. The method allows optimal joint measurement of multiple, dithered image exposures, taking into account imaging distortion and the alignment of the multiple measurements. We discuss the effects of noise bias on the likelihood distribution of galaxy ellipticity. Two sets of image simulations that mirror the observed properties of CFHTLenS have been created to establish the method's accuracy and to derive an empirical correction for the effects of noise bias.

  5. Transgenerational effects of mild heat in Arabidopsis thaliana show strong genotype specificity that is explained by climate at origin.

    Science.gov (United States)

    Groot, Maartje P; Kubisch, Alexander; Ouborg, N Joop; Pagel, Jörn; Schmid, Karl J; Vergeer, Philippine; Lampei, Christian

    2017-08-01

    Transgenerational environmental effects can trigger strong phenotypic variation. However, it is unclear how cues from different preceding generations interact. Also, little is known about the genetic variation for these life history traits. Here, we present the effects of grandparental and parental mild heat, and their combination, on four traits of the third-generation phenotype of 14 Arabidopsis thaliana genotypes. We tested for correlations of these effects with climate and constructed a conceptual model to identify the environmental conditions that favour the parental effect on flowering time. We observed strong evidence for genotype-specific transgenerational effects. On average, A. thaliana accustomed to mild heat produced more seeds after two generations. Parental effects overruled grandparental effects in all traits except reproductive biomass. Flowering was generally accelerated by all transgenerational effects. Notably, the parental effect triggered earliest flowering in genotypes adapted to dry summers. Accordingly, this parental effect was favoured in the model when early summer heat terminated the growing season and environments were correlated across generations. Our results suggest that A. thaliana can partly accustom to mild heat over two generations and genotype-specific parental effects show non-random evolutionary divergence across populations that may support climate change adaptation in the Mediterranean. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  6. The effect of whole body irradiation on the action of strong analgesics of mice

    International Nuclear Information System (INIS)

    Cvetkovicj, M.; Milovanovicj, A.; Tanasijevicj, D.

    1987-01-01

    The effect of whole body irradiation of male mice with single doses of 3 and 7 Gy ( 60 Co source) on analgesic action of three morphine-like drugs was studied. Over the first 6 days after irradiation, the analgesic effect of alfentanil and fentanyl was significantly less pronounced in irradiated animals than in control ones. During the subsequent period of 24 days till the end of experiment, the analgesic effect in irradiated animals gradually increased reaching and exceeding the control values. On the contrary, the analgesic effect of butorphanole was less pronounced in irradiated animals than in control ones, although the difference was not significantly. The difference between butorphanole and other two drugs are probably due to chemical structure and the metabolic fate in the body. (author) 8 refs.; 2 figs

  7. 3D weak lensing with spin wavelets on the ball

    Science.gov (United States)

    Leistedt, Boris; McEwen, Jason D.; Kitching, Thomas D.; Peiris, Hiranya V.

    2015-12-01

    We construct the spin flaglet transform, a wavelet transform to analyze spin signals in three dimensions. Spin flaglets can probe signal content localized simultaneously in space and frequency and, moreover, are separable so that their angular and radial properties can be controlled independently. They are particularly suited to analyzing cosmological observations such as the weak gravitational lensing of galaxies. Such observations have a unique 3D geometrical setting since they are natively made on the sky, have spin angular symmetries, and are extended in the radial direction by additional distance or redshift information. Flaglets are constructed in the harmonic space defined by the Fourier-Laguerre transform, previously defined for scalar functions and extended here to signals with spin symmetries. Thanks to various sampling theorems, both the Fourier-Laguerre and flaglet transforms are theoretically exact when applied to bandlimited signals. In other words, in numerical computations the only loss of information is due to the finite representation of floating point numbers. We develop a 3D framework relating the weak lensing power spectrum to covariances of flaglet coefficients. We suggest that the resulting novel flaglet weak lensing estimator offers a powerful alternative to common 2D and 3D approaches to accurately capture cosmological information. While standard weak lensing analyses focus on either real- or harmonic-space representations (i.e., correlation functions or Fourier-Bessel power spectra, respectively), a wavelet approach inherits the advantages of both techniques, where both complicated sky coverage and uncertainties associated with the physical modeling of small scales can be handled effectively. Our codes to compute the Fourier-Laguerre and flaglet transforms are made publicly available.

  8. Strong-field ionization of xenon dimers: The effect of two-equivalent-center interference and of driving ionic transitions

    Science.gov (United States)

    Zhang, C.; Feng, T.; Raabe, N.; Rottke, H.

    2018-02-01

    Strong-field ionization (SFI) of the homonuclear noble gas dimer Xe2 is investigated and compared with SFI of the Xe atom and of the ArXe heteronuclear dimer by using ultrashort Ti:sapphire laser pulses and photoelectron momentum spectroscopy. The large separation of the two nuclei of the dimer allows the study of two-equivalent-center interference effects on the photoelectron momentum distribution. Comparing the experimental results with a new model calculation, which is based on the strong-field approximation, actually reveals the influence of interference. Moreover, the comparison indicates that the presence of closely spaced gerade and ungerade electronic state pairs of the Xe2 + ion at the Xe2 ionization threshold, which are strongly dipole coupled, affects the photoelectron momentum distribution.

  9. Impact of the strong electromagnetic field on the QCD effective potential for homogeneous Abelian gluon field configurations

    International Nuclear Information System (INIS)

    Galilo, Bogdan V.; Nedelko, Sergei N.

    2011-01-01

    The one-loop quark contribution to the QCD effective potential for the homogeneous Abelian gluon field in the presence of an external strong electromagnetic field is evaluated. The structure of extrema of the potential as a function of the angles between chromoelectric, chromomagnetic, and electromagnetic fields is analyzed. In this setup, the electromagnetic field is considered as an external one while the gluon field represents domain structured nonperturbative gluon configurations related to the QCD vacuum in the confinement phase. Two particularly interesting gluon configurations, (anti-)self-dual and crossed orthogonal chromomagnetic and chromoelectric fields, are discussed specifically. Within this simplified framework it is shown that the strong electromagnetic fields can play a catalyzing role for a deconfinement transition. At the qualitative level, the present consideration can be seen as a highly simplified study of an impact of the electromagnetic fields generated in relativistic heavy ion collisions on the strongly interacting hadronic matter.

  10. Combining Galaxy-Galaxy Lensing and Galaxy Clustering

    Energy Technology Data Exchange (ETDEWEB)

    Park, Youngsoo [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Krause, Elisabeth [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Jain, Bhuvnesh [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Amara, Adam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Becker, Matt [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Bridle, Sarah [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Clampitt, Joseph [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Crocce, Martin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gaztanaga, Enrique [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Sanchez, Carles [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wechsler, Risa [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-01-01

    Combining galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth rate of large scale structure, a quantity that will shed light on the mechanism driving the acceleration of the Universe. The Dark Energy Survey (DES) is a prime candidate for such an analysis, with its measurements of both the distribution of galaxies on the sky and the tangential shears of background galaxies induced by these foreground lenses. By constructing an end-to-end analysis that combines large-scale galaxy clustering and small-scale galaxy-galaxy lensing, we also forecast the potential of a combined probes analysis on DES datasets. In particular, we develop a practical approach to a DES combined probes analysis by jointly modeling the assumptions and systematics affecting the different components of the data vector, employing a shared halo model, HOD parametrization, photometric redshift errors, and shear measurement errors. Furthermore, we study the effect of external priors on different subsets of these parameters. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/ optimistically constraining the growth function to 8%/4.9% with its first-year data covering 1000 square degrees, and to 4%/2.3% with its full five-year data covering 5000 square degrees.

  11. Origami with negative refractive index to generate super-lenses

    International Nuclear Information System (INIS)

    Guenneau, Fanny; Chakrabarti, Sangeeta; Guenneau, Sebastien; Ramakrishna, S Anantha

    2014-01-01

    Negative refractive index materials (NRIM) enable unique effects including superlenses with a high degree of sub-wavelength image resolution, a capability that stems from the ability of NRIM to support a host of surface plasmon states. Using a generalized lens theorem and the powerful tools of transformational optics, a variety of focusing configurations involving complementary positive and negative refractive index media can be generated. A paradigm of such complementary media are checkerboards that consist of alternating cells of positive and negative refractive index, and are associated with very singular electromagnetics. We present here a variety of multi-scale checkerboard lenses that we call origami lenses and investigate their electromagnetic properties both theoretically and computationally. Some of these meta-structures in the plane display thin bridges of complementary media, and this highly enhances their plasmonic response. We demonstrate the design of three-dimensional checkerboard meta-structures of complementary media using transformational optics to map the checkerboard onto three-dimensional corner lenses, the only restriction being that the corresponding unfolded structures in the plane are constrained by the four color-map theorem. (paper)

  12. Detection techniques for the H.E.S.S. II telescope, data modeling of gravitational lensing and emission of blazars in HE-VHE astronomy

    International Nuclear Information System (INIS)

    Barnacka, Anna

    2013-01-01

    This thesis presents the study of four aspects of high energy astronomy. The first part of my thesis is dedicated to an aspect of instrument development for imaging atmospheric Cherenkov telescopes, namely the Level 2 trigger system of the High Energy Stereoscopic System (H.E.S.S.). My work on the project focused on the algorithm development and the Monte Carlo simulations of the trigger system and overall instrument. The hardware implementation of the system is described and its expected performances are then evaluated. The H.E.S.S. array has been used to observe the blazar PKS 1510-089. The second part of my thesis deals with the data analysis and modeling of broad-band emission of this particular blazar. In part II of my thesis, I am presenting the analysis of the H.E.S.S. data: the light curve and spectrum of PKS 1510-089, together with the FERMI data and a collection of multi-wavelength data obtained with various instruments. I am presenting the model of PKS 1510-089 observations carried out during a flare recorded by H.E.S.S.. The model is based on a single zone internal shock scenario. The third part of my thesis deals with blazars observed by the FERMI-LAT, but from the point of view of other phenomena: a strong gravitational lensing. This part of my thesis shows the first evidence for gravitational lensing phenomena in high energy gamma-rays. This evidence comes from the observation of a gravitational lens system induced echo in the light curve of the distant blazar PKS 1830-211. Traditional methods for the estimation of time delays in gravitational lensing systems rely on the cross-correlation of the light curves from individual images. In my thesis, I used 300 MeV-30 GeV photons detected by the Fermi-LAT instrument. The FERMI-LAT instrument cannot separate the images of known lenses. The observed light curve is thus the superposition of individual image light curves. The FERMI-LAT instrument has the advantage of providing long, evenly spaced, time series

  13. Gravitationally Lensed Quasars in Gaia: II. Discovery of 24 Lensed Quasars

    Science.gov (United States)

    Lemon, Cameron A.; Auger, Matthew W.; McMahon, Richard G.; Ostrovski, Fernanda

    2018-04-01

    We report the discovery, spectroscopic confirmation and preliminary characterisation of 24 gravitationally lensed quasars identified using Gaia observations. Candidates were selected in the Pan-STARRS footprint with quasar-like WISE colours or as photometric quasars from SDSS, requiring either multiple detections in Gaia or a single Gaia detection near a morphological galaxy. The Pan-STARRS grizY images were modelled for the most promising candidates and 60 candidate systems were followed up with the William Herschel Telescope. 13 of the lenses were discovered as Gaia multiples and 10 as single Gaia detections near galaxies. We also discover 1 lens identified through a quasar emission line in an SDSS galaxy spectrum. The lenses have median image separation 2.13″ and the source redshifts range from 1.06 to 3.36. 4 systems are quadruply-imaged and 20 are doubly-imaged. Deep CFHT data reveal an Einstein ring in one double system. We also report 12 quasar pairs, 10 of which have components at the same redshift and require further follow-up to rule out the lensing hypothesis. We compare the properties of these lenses and other known lenses recovered by our search method to a complete sample of simulated lenses to show the lenses we are missing are mainly those with small separations and higher source redshifts. The initial Gaia data release only catalogues all images of ˜ 30% of known bright lensed quasars, however the improved completeness of Gaia data release 2 will help find all bright lensed quasars on the sky.

  14. Perspective has a strong effect on the calculation of historical contributions to global warming

    Science.gov (United States)

    Skeie, Ragnhild B.; Fuglestvedt, Jan; Berntsen, Terje; Peters, Glen P.; Andrew, Robbie; Allen, Myles; Kallbekken, Steffen

    2017-02-01

    The politically contentious issue of calculating countries’ contributions to climate change is strongly dependent on methodological choices. Different principles can be applied for distributing efforts for reducing human-induced global warming. According to the ‘Brazilian Proposal’, industrialized countries would reduce emissions proportional to their historical contributions to warming. This proposal was based on the assumption that the political process would lead to a global top-down agreement. The Paris Agreement changed the role of historical responsibilities. Whereas the agreement refers to equity principles, differentiation of mitigation efforts is delegated to each country, as countries will submit new national contributions every five years without any international negotiation. It is likely that considerations of historical contributions and distributive fairness will continue to play a key role, but increasingly so in a national setting. Contributions to warming can be used as a background for negotiations to inform and justify positions, and may also be useful for countries’ own assessment of what constitutes reasonable and fair contributions to limiting warming. Despite the fact that the decision from COP21 explicitly rules out compensation in the context of loss and damage, it is likely that considerations of historical responsibility will also play a role in future discussions. However, methodological choices have substantial impacts on calculated contributions to warming, including rank-ordering of contributions, and thus support the view that there is no single correct answer to the question of how much each country has contributed. There are fundamental value-related and ethical questions that cannot be answered through a single set of calculated contributions. Thus, analyses of historical contributions should not present just one set of results, but rather present a spectrum of results showing how the calculated contributions vary with a

  15. Strong synergistic effects in PLA/PCL blends: Impact of PLA matrix viscosity.

    Science.gov (United States)

    Ostafinska, Aleksandra; Fortelný, Ivan; Hodan, Jiří; Krejčíková, Sabina; Nevoralová, Martina; Kredatusová, Jana; Kruliš, Zdeněk; Kotek, Jiří; Šlouf, Miroslav

    2017-05-01

    Blends of two biodegradable polymers, poly(lactic acid) (PLA) and poly(ϵ-caprolactone) (PCL), with strong synergistic improvement in mechanical performance were prepared by melt-mixing using the optimized composition (80/20) and the optimized preparation procedure (a melt-mixing followed by a compression molding) according to our previous study. Three different PLA polymers were employed, whose viscosity decreased in the following order: PLC ≈ PLA1 > PLA2 > PLA3. The blends with the highest viscosity matrix (PLA1/PCL) exhibited the smallest PCL particles (d∼0.6μm), an elastic-plastic stable fracture (as determined from instrumented impact testing) and the strongest synergistic improvement in toughness (>16× with respect to pure PLA, exceeding even the toughness of pure PCL). According to the available literature, this was the highest toughness improvement in non-compatiblized PLA/PCL blends ever achieved. The decrease in the matrix viscosity resulted in an increase in the average PCL particle size and a dramatic decrease in the overall toughness: the completely stable fracture (for PLA1/PCL) changed to the stable fracture followed by unstable crack propagation (for PLA2/PCL) and finally to the completely brittle fracture (for PLA3/PCL). The stiffness of all blends remained at well acceptable level, slightly above the theoretical predictions based on the equivalent box model. Despite several previous studies, the results confirmed that PLA and PCL could behave as compatible polymers, but the final PLA/PCL toughness is extremely sensitive to the PCL particle size distribution, which is influenced by both processing conditions and PLA viscosity. PLA/PCL blends with high stiffness (due to PLA) and toughness (due to PCL) are very promising materials for medical applications, namely for the bone tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Effects of a parental program for preventing underage drinking - The NGO program strong and clear

    Directory of Open Access Journals (Sweden)

    Eriksson Charli

    2011-04-01

    Full Text Available Abstract Background The present study is an evaluation of a 3-year parental program aiming to prevent underage drinking. The intervention was implemented by a non-governmental organization and targeted parents with children aged 13-16 years old and included recurrent activities during the entire period of secondary school. The program consisted of four different types of group and self-administered activities: parent meetings, family dialogues, friend meetings, and family meetings. Methods A quasi-experimental design was used following parents and children with questionnaires during the three years of secondary school. The analytic sample consisted of 509 dyads of parents and children. Measures of parental attitudes and behaviour concerning underage drinking and adolescents' lifetime alcohol consumption and drunkenness were used. Three socio-demographic factors were included: parental education, school, and gender of the child. A Latent Growth Modelling (LGM approach was used to examine changes in parental behaviour regarding youth drinking and in young people's drinking behaviour. To test for the pre-post test differences in parental attitudes repeated measures ANOVA were used. Results The results showed that parents in the program maintained their restrictive attitude toward underage drinking to a higher degree than non-participating parents. Adolescents of participants were on average one year older than adolescents with non-participating parents when they made their alcohol debut. They were also less likely to have ever been drunk in school year 9. Conclusion The results of the study suggested that Strong and Clear contributed to maintaining parents' restrictive attitude toward underage drinking during secondary school, postponing alcohol debut among the adolescents, and significantly reducing their drunkenness.

  17. Problems with small area surveys: lensing covariance of supernova distance measurements.

    Science.gov (United States)

    Cooray, Asantha; Huterer, Dragan; Holz, Daniel E

    2006-01-20

    While luminosity distances from type Ia supernovae (SNe) are a powerful probe of cosmology, the accuracy with which these distances can be measured is limited by cosmic magnification due to gravitational lensing by the intervening large-scale structure. Spatial clustering of foreground mass leads to correlated errors in SNe distances. By including the full covariance matrix of SNe, we show that future wide-field surveys will remain largely unaffected by lensing correlations. However, "pencil beam" surveys, and those with narrow (but possibly long) fields of view, can be strongly affected. For a survey with 30 arcmin mean separation between SNe, lensing covariance leads to a approximately 45% increase in the expected errors in dark energy parameters.

  18. The skewed weak lensing likelihood: why biases arise, despite data and theory being sound.

    Science.gov (United States)

    Sellentin, Elena; Heymans, Catherine; Harnois-Déraps, Joachim

    2018-04-01

    We derive the essentials of the skewed weak lensing likelihood via a simple Hierarchical Forward Model. Our likelihood passes four objective and cosmology-independent tests which a standard Gaussian likelihood fails. We demonstrate that sound weak lensing data are naturally biased low, since they are drawn from a skewed distribution. This occurs already in the framework of ΛCDM. Mathematically, the biases arise because noisy two-point functions follow skewed distributions. This form of bias is already known from CMB analyses, where the low multipoles have asymmetric error bars. Weak lensing is more strongly affected by this asymmetry as galaxies form a discrete set of shear tracer particles, in contrast to a smooth shear field. We demonstrate that the biases can be up to 30% of the standard deviation per data point, dependent on the properties of the weak lensing survey and the employed filter function. Our likelihood provides a versatile framework with which to address this bias in future weak lensing analyses.

  19. How strong is the edge effect in the adsorption of anticancer drugs on a graphene cluster?

    Science.gov (United States)

    Rungnim, Chompoonut; Chanajaree, Rungroj; Rungrotmongkol, Thanyada; Hannongbua, Supot; Kungwan, Nawee; Wolschann, Peter; Karpfen, Alfred; Parasuk, Vudhichai

    2016-04-01

    The adsorption of nucleobase-analog anticancer drugs (fluorouracil, thioguanine, and mercaptopurine) on a graphene flake (C54H18) was investigated by shifting the site at which adsorption occurs from one end of the sheet to the other end. The counterpoise-corrected M06-2X/cc-pVDZ binding energies revealed that the binding stability decreases in the sequence thioguanine > mercaptopurine > fluorouracil. We found that adsorption near the middle of the sheet is more favorable than adsorption near the edge due to the edge effect. This edge effect is stronger for the adsorption of thioguanine or mercaptopurine than for fluorouracil adsorption. However, the edge effect reduces the binding energy of the drug to the flake by only a small amount, <5 kcal/mol, depending on the adsorption site and the alignment of the drug at this site.

  20. Seawater intrusion vulnerability indicators for freshwater lenses in strip islands

    Science.gov (United States)

    Morgan, L.; Werner, A. D.

    2014-12-01

    Freshwater lenses on small islands have been described as some of the most vulnerable aquifer systems in the world. Yet, little guidance is available regarding methods for rapidly assessing the vulnerability of freshwater lenses to the potential effects of climate change. To address this gap we employ a steady-state analytic modelling approach to develop seawater intrusion (SWI) vulnerability indicator equations. The vulnerability indicator equations quantify the propensity for SWI to occur in strip islands due to both recharge change and sea-level rise (SLR) (incorporating the effect of land surface inundation (LSI)). This work extends that of Werner et al. (2012) who developed SWI vulnerability indicator equations for unconfined and confined continental aquifers, and did not consider LSI. Flux-controlled and head-controlled conceptualisations of freshwater lenses are adopted. Under flux-controlled conditions the water table is able to rise unencumbered by land surface effects. Under head-controlled conditions the head is fixed at the centre of the lens due to, for example, centrally located topographic controls, surface water features or pumping. A number of inferences about SWI vulnerability in freshwater lenses can be made from the analysis: (1) SWI vulnerability indicators for SLR (under flux-controlled conditions) are proportional to lens thickness (or volume) and the rate of LSI and inversely proportional to island width; (2) SWI vulnerability indicators for recharge change (under flux-controlled conditions) are proportional to lens thickness (or volume) and inversely proportional to recharge; (3) SLR has greater impact under head-controlled conditions rather than flux-controlled conditions, whereas the opposite is the case for LSI and recharge change. Example applications to several case studies illustrate use of the method for rapidly ranking lenses according to vulnerability, thereby allowing for prioritisation of areas where further and more detailed SWI

  1. Strong excitonic effects in CuAlO2 delafossite transparent conductive oxides

    DEFF Research Database (Denmark)

    Laskowski, Robert; Christensen, Niels Egede; Blaha, Peter

    2009-01-01

    The imaginary part of the dielectric function of CuAlO2 has been calculated including the electron-hole correlation effects within Bethe-Salpeter formalism (BSE). In the initial step of the BSE solver the band structure was calculated within density-functional theory plus an orbital field (LDA/GG...

  2. Rapid Transition of the Hole Rashba Effect from Strong Field Dependence to Saturation in Semiconductor Nanowires.

    Science.gov (United States)

    Luo, Jun-Wei; Li, Shu-Shen; Zunger, Alex

    2017-09-22

    The electric field manipulation of the Rashba spin-orbit coupling effects provides a route to electrically control spins, constituting the foundation of the field of semiconductor spintronics. In general, the strength of the Rashba effects depends linearly on the applied electric field and is significant only for heavy-atom materials with large intrinsic spin-orbit interaction under high electric fields. Here, we illustrate in 1D semiconductor nanowires an anomalous field dependence of the hole (but not electron) Rashba effect (HRE). (i) At low fields, the strength of the HRE exhibits a steep increase with the field so that even low fields can be used for device switching. (ii) At higher fields, the HRE undergoes a rapid transition to saturation with a giant strength even for light-atom materials such as Si (exceeding 100 meV Å). (iii) The nanowire-size dependence of the saturation HRE is rather weak for light-atom Si, so size fluctuations would have a limited effect; this is a key requirement for scalability of Rashba-field-based spintronic devices. These three features offer Si nanowires as a promising platform for the realization of scalable complementary metal-oxide-semiconductor compatible spintronic devices.

  3. Effect of strong electrolytes on edible oils part 1: viscosity of ...

    African Journals Online (AJOL)

    The energy of activation (ΔEv), latent heat of vapourization (ΔLv) and molar volume of oil (Vm) were also calculated. Effect of electrolytes show that, the concentration of electrolytes increases the value of (ΔEv) and (ΔLv) whereas the value of molar volume (Vm) decrease with the concentration of oil and electrolytes. In brief ...

  4. Effect of strong electrolytes on edible oils part II: vViscosity of maize ...

    African Journals Online (AJOL)

    The electrolytes behave as structure breaker. The effect of temperature was also determined in terms of fluidity parameters, energy of activation, latent heat of vaporization, molar volume of oil and free energy change of activation for viscous flow. Journal of Applied Sciences and Environmental Management Vol. 10 (3) 2006: ...

  5. Faraday effect in rare-earth ferrite garnets located in strong magnetic fields

    International Nuclear Information System (INIS)

    Valiev, U.V.; Zvezdin, A.K.; Krinchik, G.S.; Levitin, R.Z.; Mukimov, K.M.; Popov, A.I.

    1983-01-01

    The Faraday effect is investigated experimentally in single crystal specimens of rare earth iron garnets (REIG) R 3 Fe 5 O 12 (R=Y, Gd, Tb, Dy, Er, Tm, Yb, Eu, Sm and Ho) and also in mixed iron garnets Rsub(x)Ysub(3-x)Fesub(5)Osub(12) (R=Tb, Dy). The m.easurements are carried out in pulsed magnetic fields of intensity up to 200 kOe, in a temperature range from 4.2 to 300 K and at a wavelength of the light lambda=1.15 μm. The field dependence of the Faraday effect observed in the REIG cannot be explained if only the usually considered ''paramagnetic'' contribution to the Faraday effect is taken into account. A theory is developed which, besides the paramagnetic mechanism, takes into account a diamagnetic mechanism and also the mixing of the wave functions of the ground and excited multiplets. The contributions of each of these three mechanisms to the angle of rotation of the plane of polarization by the rare earth sublattice of the iron garnet are estimated theoretically. It is concluded that the mixing mechanism contributes significantly to the field and temperature dependences of the Faraday effect in REIG

  6. Effect of inter-fibre bonding on the fracture of fibrous networks with strong interactions

    DEFF Research Database (Denmark)

    Goutianos, Stergios; Mao, Rui; Peijs, Ton

    2017-01-01

    Abstract The mechanical response of cellulose nanopaper composites is investigated using a three-dimensional (3D) finite element fibrous network model with focus on the effect of inter-fibre bonds. It is found that the Young’s modulus and strength, for fixed fibre properties, are mainly controlle...

  7. DESIGN OF THE MULTIORDER INTRAOCULAR LENSES

    Directory of Open Access Journals (Sweden)

    V. G. Kolobrodov

    2015-01-01

    Full Text Available Intraocular lenses (IOLs are used to replace the natural crystalline lens of the eye. Just few basic designs of IOLs are used clinically. Multiorder diffractive lenses (MODL which operate simultaneously in several diffractive orders were proposed to decrease the chromatic aberration. Properties analysis of MODL showed a possibility to use them to develop new designs of IOLs. The purpose of this paper was to develop a new method of designing of multiorder intraocular lenses with decreased chromatic aberration. The theoretical research of the lens properties was carried out. The diffraction efficiency dependence with the change of wavelength was studied. A computer simulation of MODL in a schematic model of the human eye was carried out. It is found the capability of the multiorder diffractive lenses to focus polychromatic light into a segment on the optical axis with high diffraction efficiency. At each point of the segment is present each component of the spectral range, which will build a color image in combination. The paper describes the new design method of intraocular lenses with reduced chromaticism and with endless adaptation. An optical system of an eye with an intraocular lens that provides sharp vision of objects located at a distance of 700 mm to infinity is modeled.

  8. Modern scleral contact lenses: A review.

    Science.gov (United States)

    van der Worp, Eef; Bornman, Dina; Ferreira, Daniela Lopes; Faria-Ribeiro, Miguel; Garcia-Porta, Nery; González-Meijome, José M

    2014-08-01

    Scleral contact lenses (ScCL) have gained renewed interest during the last decade. Originally, they were primarily used for severely compromised eyes. Corneal ectasia and exposure conditions were the primary indications. However, the indication range of ScCL in contact lens practices seems to be expanding, and it now increasingly includes less severe and even non-compromised eyes, too. All lenses that partly or entirely rest on the sclera are included under the name ScCL in this paper; although the Scleral Lens Education Society recommends further classification. When a lens partly rests on the cornea (centrally or peripherally) and partly on the sclera, it is called a corneo-scleral lens. A lens that rests entirely on the sclera is classified as a scleral lens (up to 25 mm in diameter maximum). When there is full bearing on the sclera, further distinctions of the scleral lens group include mini-scleral and large-scleral lenses. This manuscript presents a review of the current applications of different ScCL (all types), their fitting methods, and their clinical outcomes including potential adverse events. Adverse events with these lenses are rare, but the clinician needs to be aware of them to avoid further damage in eyes that often are already compromised. The use of scleral lenses for non-pathological eyes is discussed in this paper. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  9. Plasma lenses for focusing relativistic electron beams

    International Nuclear Information System (INIS)

    Govil, R.; Wheeler, S.; Leemans, W.

    1997-01-01

    The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a plasma focusing scheme has been proposed. Plasma lenses can be overdense (plasma density, n p much greater than electron beam density, n b ) or underdense (n p less than 2 n b ). In overdense lenses the space-charge force of the electron beam is canceled by the plasma and the remaining magnetic force causes the electron beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the electron beam cancel, allowing the plasma ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by plasma ions. The underdense lens can be improved by tapering the density of the plasma for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic plasma lenses to avoid the Oide limit on spot size due to synchrotron radiation by the electron beam. The plasma lens experiment at the Beam Test Facility (BTF) is designed to study the properties of plasma lenses in both overdense and underdense regimes. In particular, important issues such as electron beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated

  10. HerMES: A DEFICIT IN THE SURFACE BRIGHTNESS OF THE COSMIC INFRARED BACKGROUND DUE TO GALAXY CLUSTER GRAVITATIONAL LENSING

    International Nuclear Information System (INIS)

    Zemcov, M.; Cooray, A.; Bock, J.; Dowell, C. D.; Nguyen, H. T.; Blain, A.; Béthermin, M.; Clements, D. L.; Conley, A.; Glenn, J.; Conversi, L.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Griffin, M.; Halpern, M.; Marsden, G.; Jullo, E.; Kneib, J.-P.; Richard, J.

    2013-01-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I 250μm >0.69 -0.03 +0.03 (stat.) -0.06 +0.11 (sys.) MJy sr –1 , with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe this effect in existing high angular resolution data at other wavelengths where the CIB is bright, which would allow tests of models of the faint source component of the CIB.

  11. Fourier heat conduction as a strong kinetic effect in one-dimensional hard-core gases

    Science.gov (United States)

    Zhao, Hanqing; Wang, Wen-ge

    2018-01-01

    For a one-dimensional (1D) momentum conserving system, intensive studies have shown that generally its heat current autocorrelation function (HCAF) tends to decay in a power-law manner and results in the breakdown of the Fourier heat conduction law in the thermodynamic limit. This has been recognized to be a dominant hydrodynamic effect. Here we show that, instead, the kinetic effect can be dominant in some cases and leads to the Fourier law for finite-size systems. Usually the HCAF undergoes a fast decaying kinetic stage followed by a long slowly decaying hydrodynamic tail. In a finite range of the system size, we find that whether the system follows the Fourier law depends on whether the kinetic stage dominates. Our Rapid Communication is illustrated by the 1D hard-core gas models with which the HCAF is derived analytically and verified numerically by molecular dynamics simulations.

  12. Biological Maturity Status Strongly Intensifies the Relative Age Effect in Alpine Ski Racing.

    Directory of Open Access Journals (Sweden)

    Lisa Müller

    Full Text Available The relative age effect (RAE is a well-documented phenomenon in youth sports. This effect exists when the relative age quarter distribution of selected athletes shows a biased distribution with an over-representation of relatively older athletes. In alpine ski racing, it exists in all age categories (national youth levels up to World Cup. Studies so far could demonstrate that selected ski racers are relatively older, taller and heavier. It could be hypothesized that relatively younger athletes nearly only have a chance for selection if they are early maturing. However, surprisingly this influence of the biological maturity status on the RAE could not be proven, yet. Therefore, the aim of the present study was to investigate the influence of the biological maturity status on the RAE in dependence of the level of competition. The study investigated 372 elite youth ski racers: 234 provincial ski racers (P-SR; high level of competition and 137 national ski racers (N-SR; very high level of competition. Anthropometric characteristics were measured to calculate the age at peak height velocity (APHV as an indicator of the biological maturity status. A significant RAE was present among both P-SR and N-SR, with a larger effect size among the latter group. The N-SR significantly differed in APHV from the P-SR. The distribution of normal, early and late maturing athletes significantly differed from the expected normal distribution among the N-SR, not among the P-SR. Hardly any late maturing N-SR were present; 41.7% of the male and 34% of the female N-SR of the last relative age quarter were early maturing. These findings clearly demonstrate the significant influence of the biological maturity status on the selection process of youth alpine ski racing in dependence of the level of competition. Relatively younger athletes seem to have a chance of selection only if they are early maturing.

  13. Biological Maturity Status Strongly Intensifies the Relative Age Effect in Alpine Ski Racing.

    Science.gov (United States)

    Müller, Lisa; Müller, Erich; Hildebrandt, Carolin; Raschner, Christian

    2016-01-01

    The relative age effect (RAE) is a well-documented phenomenon in youth sports. This effect exists when the relative age quarter distribution of selected athletes shows a biased distribution with an over-representation of relatively older athletes. In alpine ski racing, it exists in all age categories (national youth levels up to World Cup). Studies so far could demonstrate that selected ski racers are relatively older, taller and heavier. It could be hypothesized that relatively younger athletes nearly only have a chance for selection if they are early maturing. However, surprisingly this influence of the biological maturity status on the RAE could not be proven, yet. Therefore, the aim of the present study was to investigate the influence of the biological maturity status on the RAE in dependence of the level of competition. The study investigated 372 elite youth ski racers: 234 provincial ski racers (P-SR; high level of competition) and 137 national ski racers (N-SR; very high level of competition). Anthropometric characteristics were measured to calculate the age at peak height velocity (APHV) as an indicator of the biological maturity status. A significant RAE was present among both P-SR and N-SR, with a larger effect size among the latter group. The N-SR significantly differed in APHV from the P-SR. The distribution of normal, early and late maturing athletes significantly differed from the expected normal distribution among the N-SR, not among the P-SR. Hardly any late maturing N-SR were present; 41.7% of the male and 34% of the female N-SR of the last relative age quarter were early maturing. These findings clearly demonstrate the significant influence of the biological maturity status on the selection process of youth alpine ski racing in dependence of the level of competition. Relatively younger athletes seem to have a chance of selection only if they are early maturing.

  14. A systematic review of drug treatment of vulvodynia: evidence of a strong placebo effect.

    Science.gov (United States)

    Varella Pereira, Glaucia Miranda; Marcolino, Milena Soriano; Nogueira Reis, Zilma Silveira; de Castro Monteiro, Marilene Vale

    2018-03-23

    Vulvodynia is the most common type of chronic pelvic pain and dyspareunia in premenopausal women. The effect of drugs for the treatment of vulvodynia remains poorly discussed. To conduct a systematic review of randomised controlled studies which assess medications used to treat vulvar pain in vulvodynia. Web of Science, Cochrane Library, EBSCO Academic, LILACS and MEDLINE were searched from 1985 to September 2016. Randomised controlled trials comparing any kind of medication for vulvodynia treatment with placebo or with another medication in adult patients were included. The two investigators independently conducted data extraction. The synthesis was provided by the pain reduction index. Study quality assessment was performed using the Cochrane Handbook for Systematic Reviews of Intervention and analysis of publication bias was conducted. Five studies were included in qualitative synthesis with a number of the participants varied from 30 to 133 among the eligible studies resulting 297. The pain reduction rates of patients with vulvodynia assessed by Q-tipped Cotton Test and visual analogue scale varied between studies. Placebo was shown to be as effective as any medication. There is a need for further studies evaluating topical monotherapy for the treatment of vulvodynia, since they are the main drugs used in clinical practice. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. <strong>Dimensional asymptotics of effective actions on S^n, and proof of Bär-Schopka's conjecturestrong>

    DEFF Research Database (Denmark)

    Møller, Niels Martin

    We study the dimensional asymptotics of the effective actions, or functional determinants, for the Dirac operator D and Laplacians \\Delta +\\beta R on round S^n. For Laplacians the behavior depends on ``the coupling strength'' \\beta, and one cannot in general expect a finite limit of \\zeta'(0), an...... spheres to unit volume, since \\lim_{k\\to\\infty}\\det(\\Delta, S_\\mathrm{rescaled}^{2k+1})=\\frac{1}{2\\pi e}....

  16. Gravitational Lensing from a Spacetime Perspective

    Directory of Open Access Journals (Sweden)

    Perlick Volker

    2004-09-01

    Full Text Available The theory of gravitational lensing is reviewed from a spacetime perspective, without quasi-Newtonian approximations. More precisely, the review covers all aspects of gravitational lensing where light propagation is described in terms of lightlike geodesics of a metric of Lorentzian signature. It includes the basic equations and the relevant techniques for calculating the position, the shape, and the brightness of images in an arbitrary general-relativistic spacetime. It also includes general theorems on the classification of caustics, on criteria for multiple imaging, and on the possible number of images. The general results are illustrated with examples of spacetimes where the lensing features can be explicitly calculated, including the Schwarzschild spacetime, the Kerr spacetime, the spacetime of a straight string, plane gravitational waves, and others.

  17. Effects of strong network modifiers on Fe3+/Fe2+ in silicate melts: an experimental study

    Science.gov (United States)

    Borisov, Alexander; Behrens, Harald; Holtz, Francois

    2017-05-01

    The effect of CaO, Na2O, and K2O on ferric/ferrous ratio in model multicomponent silicate melts was investigated in the temperature range 1450-1550 °C at 1-atm total pressure in air. It is demonstrated that the addition of these network modifier cations results in an increase of Fe3+/Fe2+ ratio. The influence of network modifier cations on the ferric/ferrous ratio increases in the order Ca SiO2-TiO2-Al2O3-FeO-Fe2O3-MgO-CaO-Na2O-K2O-P2O5 melts at air conditions.

  18. In-medium covariant propagator of baryons under a strong magnetic field: Effect of the intrinsic magnetic moments

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, R.M.; Paoli, A.L. de [Universidad Nacional de La Plata, and IFLP, Departamento de Fisica, Facultad de Ciencias Exactas, La Plata (Argentina)

    2016-11-15

    We obtain the covariant propagator at finite temperature for interacting baryons immersed in a strong magnetic field. The effect of the intrinsic magnetic moments on the Green function are fully taken into account. We make an expansion in terms of eigenfunctions of a Dirac field, which leads us to a compact form of its propagator. We present some simple applications of these propagators, where the statistical averages of nuclear currents and energy density are evaluated. (orig.)

  19. Absence of strong strain effects in behavioral analyses of Shank3-deficient mice

    Directory of Open Access Journals (Sweden)

    Elodie Drapeau

    2014-06-01

    Full Text Available Haploinsufficiency of SHANK3, caused by chromosomal abnormalities or mutations that disrupt one copy of the gene, leads to a neurodevelopmental syndrome called Phelan-McDermid syndrome, symptoms of which can include absent or delayed speech, intellectual disability, neurological changes and autism spectrum disorders. The SHANK3 protein forms a key structural part of the post-synaptic density. We previously generated and characterized mice with a targeted disruption of Shank3 in which exons coding for the ankyrin-repeat domain were deleted and expression of full-length Shank3 was disrupted. We documented specific deficits in synaptic function and plasticity, along with reduced reciprocal social interactions, in Shank3 heterozygous mice. Changes in phenotype owing to a mutation at a single locus are quite frequently modulated by other loci, most dramatically when the entire genetic background is changed. In mice, each strain of laboratory mouse represents a distinct genetic background and alterations in phenotype owing to gene knockout or transgenesis are frequently different across strains, which can lead to the identification of important modifier loci. We have investigated the effect of genetic background on phenotypes of Shank3 heterozygous, knockout and wild-type mice, using C57BL/6, 129SVE and FVB/Ntac strain backgrounds. We focused on observable behaviors with the goal of carrying out subsequent analyses to identify modifier loci. Surprisingly, there were very modest strain effects over a large battery of analyses. These results indicate that behavioral phenotypes associated with Shank3 haploinsufficiency are largely strain-independent.

  20. Effects of strong electron correlations in Ti8C12 Met-Car

    International Nuclear Information System (INIS)

    Varganov, Sergey A.; Gordon, Mark S.

    2006-01-01

    The results of multireference configuration interaction (MRCI) with single and double excitations and single reference coupled cluster (CCSD(T)) calculations on Ti 8 C 12 metallocarbohedryne (Met-Car) are reported. The distortions of the T d structure to D 2d and C 3v structures due to the Jahn-Teller effect are studied. It is shown that the Ti 8 C 12 wave function has significant multireference character. The choice of the active space for multireference self-consistent field (MCSCF) calculations is discussed. The failure of multireference perturbation theory with a small active space is attributed to multiple intruder states. A new, novel type of MCSCF calculation, ORMAS (occupation restricted multiple active spaces) with a large active space are carried out for several electronic states of Ti 8 C 12 . The Jahn-Teller distorted D 2d 1 A 1 (nearly T d ) structure is predicted to be the Ti 8 C 12 ground state. Predictions of the Ti 8 C 12 ionization potential with different ab initio methods are presented

  1. Noise-induced effects on multicellular biopacemaker spontaneous activity: Differences between weak and strong pacemaker cells

    Science.gov (United States)

    Aghighi, Alireza; Comtois, Philippe

    2017-09-01

    Self-organization of spontaneous activity of a network of active elements is important to the general theory of reaction-diffusion systems as well as for pacemaking activity to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes, consisting of resting and pacemaker cells, exhibit spontaneous activation of their electrical activity. Similarly, one proposed approach to the development of biopacemakers as an alternative to electronic pacemakers for cardiac therapy is based on heterogeneous cardiac cells with resting and spontaneously beating phenotypes. However, the combined effect of pacemaker characteristics, density, and spatial distribution of the pacemaker cells on spontaneous activity is unknown. Using a simple stochastic pattern formation algorithm, we previously showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of pacemaker cells. In this study, we show that this behavior is dependent on the pacemaker cell characteristics, with weaker pacemaker cells requiring higher density and larger clusters to sustain multicellular activity. These multicellular structures also demonstrated an increased sensitivity to voltage noise that favored spontaneous activity at lower density while increasing temporal variation in the period of activity. This information will help researchers overcome the current limitations of biopacemakers.

  2. Lense-Thirring precession around neutron stars with known spin

    Science.gov (United States)

    Van Doesburgh, Marieke; van der Klis, Michiel

    2016-07-01

    Quasi periodic oscillations (QPOs) between 300 and 1200 Hz in the X-ray emission from low mass X-ray binaries have been linked to Keplerian orbital motion at the inner edge of accretion disks. Lense-Thirring precession is precession of the line of nodes of inclined orbits with respect to the equatorial plane of a rotating object due to the general relativistic effect of frame dragging. The Lense-Thirring model of Stella and Vietri (1998) explains QPOs observed in neutron star low mass X-ray binaries at frequencies of a few tens of Hz by the nodal precession of the orbits at the inner disk edge at a precession frequency, ν_{LT} , identical to the Lense-Thirring precession of a test particle orbit. A quadratic relation between ν_{LT} and the Keplerian orbital frequency, and a linear dependence on spin frequency are predicted. In early work (van Straaten et al., 2003) this quadratic relation was confirmed to remarkable precision in three objects of uncertain spin. Since the initial work, many neutron star spin frequencies have been measured in X-ray sources that show QPOs at both low and high frequency. Using archival data from the Rossi X-ray Timing Explorer, we compare the Lense-Thirring prediction to the properties of quasi periodic oscillations measured in a sample of 14 low mass X-ray binaries of which the neutron star spin frequencies can be inferred from their bursting behaviour. We find that in the range predicted for the precession frequency, we can distinguish two different oscillations that often occur simultaneously. In previous works, these two oscillations have often been confused. For both frequencies, we find correlations with inferred Keplerian frequency characterized by power laws with indices that differ significantly from the prediction of 2.0 and therefore inconsistent with the Lense-Thirring model. Also, the specific moment of inertia of the neutron star required by the observed frequencies exceeds values predicted for realistic equations of

  3. Myopia control in children through refractive therapy gas permeable contact lenses: is it for real?

    Science.gov (United States)

    Koffler, Bruce H; Sears, James J

    2013-12-01

    To compare the safety and efficacy of orthokeratology as a nonsurgical treatment for myopia in children with alternate methods, such as soft contact lenses, rigid gas permeable lenses, and spectacles, throughout multiple studies. Perspective with literature review. Analysis of recent studies to determine the safety and effectiveness of orthokeratology versus soft contact lenses, rigid gas permeable lenses, and spectacles in children. In all of the studies reviewed, the use of orthokeratology lenses proved to reduce myopia, to improve visual acuity, and, with the exception of the SMART study, to reduce the rate of axial elongation. Orthokeratology has been shown to be as effective as other methods in treating myopia and to be more effective at treating axial elongation. There were no major adverse events in any of the studies comparing orthokeratology with other methods of myopia treatment. Studies show that the use of orthokeratology is a safe and efficacious nonsurgical treatment for myopia and that it is capable of slowing axial elongation, making it an effective myopic treatment for children. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Gravitational Lensing Signatures of Long Cosmic Strings

    CERN Document Server

    De Laix, A A; Vachaspati, T; Laix, Andrew A. de; Krauss, Lawrence M.; Vachaspati, Tanmay

    1997-01-01

    The gravitational lensing by long, wiggly cosmic strings is shown to produce a large number of lensed images of a background source. In addition to pairs of images on either side of the string, a number of small images outline the string due to small-scale structure on the string. This image pattern could provide a highly distinctive signature of cosmic strings. Since the optical depth for multiple imaging of distant quasar sources by long strings may be comparable to that by galaxies, these image patterns should be clearly observable in the next generation of redshift surveys such as the Sloan Digital Sky Survey.

  5. Achromatic Cooling Channel with Li Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Balbekov, V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2002-04-29

    A linear cooling channel with Li lenses, solenoids, and 201 MHz RF cavities is considered. A special lattice design is used to minimize chromatic aberrations by suppression of several betatron resonances. Transverse emittance of muon beam decreases from 2 mm to 0.5 mm at the channel of about 110 m length. Longitudinal heating is modest, therefore transmission of the channel is rather high: 96% without decay and 90% with decay. Minimal beam emittance achievable by similar channel estimated as about 0.25 mm at surface field of Li lenses 10 T.

  6. Rigid gas permeable lenses and patient management.

    Science.gov (United States)

    Terry, R; Schnider, C; Holden, B A

    1989-01-01

    The introduction of new rigid gas permeable (RGP) contact lens materials provides the practitioner with a number of alternatives for patient management. But whatever the lens materials used, problems related to the lenses, care and maintenance solutions, and patients may arise. This paper examines concerns such as parameter instability, durability of lenses, compatibility of materials and solutions, patient education and compliance, 3 and 9 o'clock staining, corneal distortion, and lid changes. Suggestions are made on ways to avoid or minimize problems related to RGP lens wear.

  7. Modern scleral contact lenses : a review

    OpenAIRE

    van der Worp, Eef; Bornman, Dina; Ferreira, Daniela Lopes; Ribeiro, Miguel Faria; Garcia-Porta, Nery; González-Méijome, José Manuel

    2014-01-01

    Scleral contact lenses (ScCL) have gained renewed interest during the last decade. Originally, they wereprimarily used for severely compromised eyes. Corneal ectasia and exposure conditions were the primaryindications. However, the indication range of ScCL in contact lens practices seems to be expanding, andit now increasingly includes less severe and even non-compromised eyes, too.All lenses that partly or entirely rest on the sclera are included under the name ScCL in this paper;although th...

  8. <strong>EFFECTS OF HYALURONAN ON THREE-DIMENSIONAL MICROARCHITECTURE OF SUBCHONDRAL BONE TISSUES IN GUINEA PIG PRIMARY OSTEOARTHROSISstrong>

    DEFF Research Database (Denmark)

    Ding, Ming

    ; and the control groups received vehicle. After sacrifice, the left tibiae were harvested and micro-CT scanned, followed by mechanical testing and collagen and mineral determination. Results: The HA-treated groups had almost normal cartilage, whereas the control groups had typical osteoarthrosis (OA......-term study, these latter changes were more pronounced, with an additionally significant decrease in connectivity and bone surface density. HA groups had greater bone mineral concentration and mineral density, lower collagen to mineral ratio, and preserved the mechanical properties of cancellous bone...... level, and effectively changes the subchondral bone tissue microarchitecture, collagen and mineral content and density without altering the mechanical properties of cancellous bone. The most striking features are the microarchitectural changes in the subchondral cancellous bone that lead to lower bone...

  9. A Solar Eruption from a Weak Magnetic Field Region with Relatively Strong Geo-Effectiveness

    Science.gov (United States)

    Wang, R.

    2017-12-01

    A moderate flare eruption giving rise to a series of geo-effectiveness on 2015 November 4 caught our attentions, which originated from a relatively weak magnetic field region. The associated characteristics near the Earth are presented, which indicates that the southward magnetic field in the sheath and the ICME induced a geomagnetic storm sequence with a Dst global minimum of 90 nT. The ICME is indicated to have a small inclination angle by using a Grad-Shafranov technique, and corresponds to the flux rope (FR) structure horizontally lying on the solar surface. A small-scale magnetic cancelling feature was detected which is beneath the FR and is co-aligned with the Atmospheric Imaging Assembly (AIA) EUV brightening prior to the eruption. Various magnetic features for space-weather forecasting are computed by using a data product from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) called Space-weather HMI Active Region Patches (SHARPs), which help us identify the changes of the photospheric magnetic fields during the magnetic cancellation process and prove that the magnetic reconnection associated with the flux cancellation is driven by the magnetic shearing motion on the photosphere. An analysis on the distributions at different heights of decay index is carried out. Combining with a filament height estimation method, the configurations of the FR is identified and a decay index critical value n = 1 is considered to be more appropriate for such a weak magnetic field region. Through a comprehensive analysis to the trigger mechanisms and conditions of the eruption, a clearer scenario of a CME from a relatively weak region is presented.

  10. Maturity Status Strongly Influences the Relative Age Effect in International Elite Under-9 Soccer

    Directory of Open Access Journals (Sweden)

    Lisa Müller, Josef Gehmaier, Christoph Gonaus, Christian Raschner, Erich Müller

    2018-06-01

    Full Text Available The aim of the study was to assess the role of the relative age effect (RAE and to investigate the influence of the biological maturity status on the RAE in international under-9 soccer. The birth dates of 222 male participants of the U9 Eurochampionship Soccer Tournament in Vienna in 2016 were analyzed and divided into four relative age quarters (Q1-Q4 and the biological maturity status was assessed with the age at peak height velocity (APHV method. Based on the mean±standard deviation of the APHV, the athletes were divided into three groups of maturity: early, normal and late maturing. Chi-Square-tests were used to assess the difference between the observed and the expected even relative age quarter distribution and to evaluate the difference between the observed distribution of early, normal and late maturing athletes and the expected normal distribution. A univariate analysis of variance was performed to assess differences in the APHV between the relative age quarters. A RAE was present (χ2 = 23.87; p < 0.001; ω = 0.33. A significant difference was found in APHV between the four relative age quarters (F = 9.906; p < 0.001; relatively older athletes were significantly less mature. A significant difference was found between the distribution of early, normal and late maturing athletes and the expected normal distribution for athletes of Q1 (high percentage of late maturing athletes: 27%; χ2 = 17.69; p < 0.001; ω = 0.46 and of Q4 (high percentage of early maturing soccer players: 31%; χ2 = 12.08; p = 0.002; ω = 0.58. These findings demonstrated that the selection process in international soccer, with athletes younger than 9 years, seems to be associated with the biological maturity status and the relative age. Relatively younger soccer players seem to have a better chance for selection for international tournaments, if they enter puberty at an earlier age, whereas relatively older athletes seem to have an increased likelihood for

  11. High-speed optical signal processing using time lenses

    DEFF Research Database (Denmark)

    Galili, Michael; Hu, Hao; Guan, Pengyu

    2015-01-01

    This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

  12. Self-assembly of a novel beta-In2S3 nanostructure exhibiting strong quantum confinement effects.

    Science.gov (United States)

    Zhang, Wu; Ma, Dekun; Huang, Zhen; Tang, Qun; Xie, Qin; Qian, Yitai

    2005-05-01

    The 3D beta-In2S3 flowerlike architecture assembled from nanoflakes was prepared via a novel complex-precursor assisted (CPA) solvothermal route. The as-prepared beta-In2S3 powder was characterized by X-ray diffraction pattern (XRD), X-ray photoelectron spectra (XPS), transition electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), ultraviolet-visible light (UV-vis) spectra, and photoluminescence spectrum. The novel 3D beta-In2S3 nanostructure exhibit a strong quantum confinement effect. FT-IR spectra were used to investigate the coordinative chemical effect in the complex. A possible mechanism was discussed.

  13. Hall effect in a strong magnetic field: Direct comparisons of compressible magnetohydrodynamics and the reduced Hall magnetohydrodynamic equations

    International Nuclear Information System (INIS)

    Martin, L. N.; Dmitruk, P.; Gomez, D. O.

    2010-01-01

    In this work we numerically test a model of Hall magnetohydrodynamics in the presence of a strong mean magnetic field: the reduced Hall magnetohydrodynamic model (RHMHD) derived by [Gomez et al., Phys. Plasmas 15, 102303 (2008)] with the addition of weak compressible effects. The main advantage of this model lies in the reduction of computational cost. Nevertheless, up until now the degree of agreement with the original Hall MHD system and the range of validity in a regime of turbulence were not established. In this work direct numerical simulations of three-dimensional Hall MHD turbulence in the presence of a strong mean magnetic field are compared with simulations of the weak compressible RHMHD model. The results show that the degree of agreement is very high (when the different assumptions of RHMHD, such as spectral anisotropy, are satisfied). Nevertheless, when the initial conditions are isotropic but the mean magnetic field is maintained strong, the results differ at the beginning but asymptotically reach a good agreement at relatively short times. We also found evidence that the compressibility still plays a role in the dynamics of these systems, and the weak compressible RHMHD model is able to capture these effects. In conclusion the weak compressible RHMHD model is a valid approximation of the Hall MHD turbulence in the relevant physical context.

  14. Probing strong-field general relativity near black holes

    CERN Multimedia

    CERN. Geneva; Alvarez-Gaumé, Luís

    2005-01-01

    Nature has sprinkled black holes of various sizes throughout the universe, from stellar mass black holes in X-ray sources to supermassive black holes of billions of solar masses in quasars. Astronomers today are probing the spacetime near black holes using X-rays, and gravitational waves will open a different view in the near future. These tools give us an unprecedented opportunity to test ultra-strong-field general relativity, including the fundamental theorem of the uniqueness of the Kerr metric and Roger Penrose's cosmic censorship conjecture. Already, fascinating studies of spectral lines are showing the extreme gravitational lensing effects near black holes and allowing crude measurements of black hole spin. When the ESA-NASA gravitational wave detector LISA begins its observations in about 10 years, it will make measurements of dynamical spacetimes near black holes with an accuracy greater even than that which theoreticians can reach with their computations today. Most importantly, when gravitational wa...

  15. Temperature changes in contact lenses in connection with radiation from welding arcs.

    Science.gov (United States)

    Lövsund, P; Nilsson, S E; Lindh, H; Oberg, P A

    1979-09-01

    Because of reports of risks associated with the use of contact lenses during exposure to welding arcs, the temperature changes in soft contact lenses were recorded in connection with certain types of welding [manual metal arc (MMA) welding, tungsten inert-gas (TIG) welding, and metal inert-gas (MIG) welding], both with free-hanging lenses and lenses applied to the eyes of anesthetized rabbits. A great increase in temperature was noted, especially with MMA welding. At a distance of 0.4 m the temperature of a lens on a rabbit eye rose from about 35 to 50 degrees C within 6 min, whereas the air temperature only increased from 23 to 30 degrees C. The increase was the greatest at the beginning of the welding period. Most of the lenses completely dried out during the experiment, and there would seem to be a potential risk that the lens would adhere to the cornea. One safety glass screen (DIN 10 A) proved effective in preventing the rise in temperature in contact lenses during MMA welding. Even though it is impossible to direct the eyes at the arc for a prolonged period of time, the use of contact lenses in connection with at least certain types of welding is not to be recommended without the use of a suitable safety glass screen (or safety glasses). With regard to the large number of particles in the welding environment, also a risk factor for contact lens wearers, it is doubtful whether even safety glasses or screens are satisfactory unless they fit closely.

  16. Low-energy beam transport using space-charge lenses

    International Nucle