The FLARE mission: deep and wide-field 1-5um imaging and spectroscopy for the early universe: a proposal for M5 cosmic vision call

NASA Astrophysics Data System (ADS)

Burgarella, D.; Levacher, P.; Vives, S.; Dohlen, K.; Pascal, S.

2016-07-01

FLARE (First Light And Reionization Explorer) is a space mission that will be submitted to ESA (M5 call). Its primary goal (~80% of lifetime) is to identify and study the universe before the end of the reionization at z > 6. A secondary objective (~20% of lifetime) is to survey star formation in the Milky Way. FLARE's strategy optimizes the science return: imaging and spectroscopic integral-field observations will be carried out simultaneously on two parallel focal planes and over very wide instantaneous fields of view. FLARE will help addressing two of ESA's Cosmic Vision themes: a) << How did the universe originate and what is it made of? » and b) « What are the conditions for planet formation and the emergence of life? >> and more specifically, << From gas and dust to stars and planets >>. FLARE will provide to the ESA community a leading position to statistically study the early universe after JWST's deep but pin-hole surveys. Moreover, the instrumental development of wide-field imaging and wide-field integral-field spectroscopy in space will be a major breakthrough after making them available on ground-based telescopes.

Witnessing the reionization history using Cosmic Microwave Background observation from Planck

NASA Astrophysics Data System (ADS)

Hazra, Dhiraj Kumar; Smoot, George F.

2017-11-01

We constrain the history of reionization using the data from Planck 2015 Cosmic Microwave Background (CMB) temperature and polarization anisotropy observations. We also use prior constraints on the reionization history at redshifts ~7-8 obtained from Lyman-α emission observations. Using the free electron fractions at different redshifts as free parameters, we construct the complete reionization history using polynomials. Our construction provides an extremely flexible framework to search for the history of reionization as a function of redshifts. We present a conservative and an optimistic constraint on reionization that are categorized by the flexibilities of the models and datasets used to constrain them, and we report that CMB data marginally favors extended reionization histories. In both the cases, we find the mean values of optical depth to be larger (≈0.09 and 0.1) than what we find in standard steplike reionization histories (0.079 ± 0.017). At the same time we also find that the maximum free electron fraction allowed by the data for redshifts more than 15 is ~0.25 at 95.4% confidence limit in the case of optimistic constraint.

Will nonlinear peculiar velocity and inhomogeneous reionization spoil 21 cm cosmology from the epoch of reionization?

PubMed

Shapiro, Paul R; Mao, Yi; Iliev, Ilian T; Mellema, Garrelt; Datta, Kanan K; Ahn, Kyungjin; Koda, Jun

2013-04-12

The 21 cm background from the epoch of reionization is a promising cosmological probe: line-of-sight velocity fluctuations distort redshift, so brightness fluctuations in Fourier space depend upon angle, which linear theory shows can separate cosmological from astrophysical information. Nonlinear fluctuations in ionization, density, and velocity change this, however. The validity and accuracy of the separation scheme are tested here for the first time, by detailed reionization simulations. The scheme works reasonably well early in reionization (≲40% ionized), but not late (≳80% ionized).

Planck intermediate results. XLVII. Planck constraints on reionization history

NASA Astrophysics Data System (ADS)

Planck Collaboration; Adam, R.; Aghanim, N.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Battye, R.; Benabed, K.; 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.; Calabrese, E.; Cardoso, J.-F.; Carron, J.; Chiang, H. C.; Colombo, L. P. L.; Combet, C.; Comis, B.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Di Valentino, E.; Dickinson, C.; Diego, J. M.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fantaye, Y.; Finelli, F.; Forastieri, F.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Gerbino, M.; Ghosh, T.; González-Nuevo, J.; Górski, K. M.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Helou, G.; Henrot-Versillé, S.; Herranz, D.; Hivon, E.; Huang, Z.; Ilić, S.; Jaffe, A. H.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Knox, L.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Langer, M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Le Jeune, M.; Levrier, F.; Lewis, A.; Liguori, M.; Lilje, P. B.; López-Caniego, M.; Ma, Y.-Z.; Macías-Pérez, J. F.; Maggio, G.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Matarrese, S.; Mauri, N.; McEwen, J. D.; Meinhold, P. R.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Naselsky, P.; Natoli, P.; Oxborrow, C. A.; Pagano, L.; Paoletti, D.; Partridge, B.; Patanchon, G.; Patrizii, L.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Plaszczynski, S.; Polastri, L.; Polenta, G.; Puget, J.-L.; Rachen, J. P.; Racine, B.; Reinecke, M.; Remazeilles, M.; Renzi, A.; Rocha, G.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Ruiz-Granados, B.; Salvati, L.; Sandri, M.; Savelainen, M.; Scott, D.; Sirri, G.; Sunyaev, R.; Suur-Uski, A.-S.; Tauber, J. A.; Tenti, M.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Valiviita, J.; Van Tent, F.; Vielva, P.; Villa, F.; Vittorio, N.; Wandelt, B. D.; Wehus, I. K.; White, M.; Zacchei, A.; Zonca, A.

2016-12-01

We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058 ± 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric or an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Δz < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z ≃ 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. We show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.

Dark-ages reionization and galaxy formation simulation V: morphology and statistical signatures of reionization

NASA Astrophysics Data System (ADS)

Geil, Paul M.; Mutch, Simon J.; Poole, Gregory B.; Angel, Paul W.; Duffy, Alan R.; Mesinger, Andrei; Wyithe, J. Stuart B.

2016-10-01

We use the Dark-ages, Reionization And Galaxy formation Observables from Numerical Simulations (DRAGONS) framework to investigate the effect of galaxy formation physics on the morphology and statistics of ionized hydrogen (H II) regions during the Epoch of Reioinization (EoR). DRAGONS self-consistently couples a semi-analytic galaxy formation model with the inhomogeneous ionizing UV background, and can therefore be used to study the dependence of morphology and statistics of reionization on feedback phenomena of the ionizing source galaxy population. Changes in galaxy formation physics modify the sizes of H II regions and the amplitude and shape of 21-cm power spectra. Of the galaxy physics investigated, we find that supernova feedback plays the most important role in reionization, with H II regions up to ≈20 per cent smaller and a fractional difference in the amplitude of power spectra of up to ≈17 per cent at fixed ionized fraction in the absence of this feedback. We compare our galaxy formation-based reionization models with past calculations that assume constant stellar-to-halo mass ratios and find that with the correct choice of minimum halo mass, such models can mimic the predicted reionization morphology. Reionization morphology at fixed neutral fraction is therefore not uniquely determined by the details of galaxy formation, but is sensitive to the mass of the haloes hosting the bulk of the ionizing sources. Simple EoR parametrizations are therefore accurate predictors of reionization statistics. However, a complete understanding of reionization using future 21-cm observations will require interpretation with realistic galaxy formation models, in combination with other observations.

Constraints on patchy reionization from Planck CMB temperature trispectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Namikawa, Toshiya

Here, we present constraints on the patchy reionization by measuring the trispectrum of the Planck 2015 cosmic microwave background (CMB) temperature anisotropies. The patchy reionization leads to anisotropies in the CMB optical depth, and the statistics of the observed CMB anisotropies is altered. Here, we estimate the trispectrum of the CMB temperature anisotropies to constrain spatial variation of the optical depth. We show that the measured trispectrum is consistent with that from the standard lensed CMB simulation at 2σ. While no evidence of the patchy reionization is found in the Planck 2015 temperature trispectrum, the CMB constraint on the patchymore » reionization is significantly improved from previous works. Assuming the analytic bubble-halo model of Wang and Hu (2006), the constraint obtained in this work rules out the typical bubble size at the ionization fraction of ~ 0.5 as R ≳ 10 Mpc. Further, our constraint implies that large-scale B -modes from the patchy reionization are not a significant contamination in detecting the primordial gravitational waves of r ≳ 0.001 if the B mode induced by the patchy reionization is described by Dvorkin et al. (2009). The CMB trispectrum data starts to provide meaningful constraints on the patchy reionization.« less

Constraints on patchy reionization from Planck CMB temperature trispectrum

NASA Astrophysics Data System (ADS)

Namikawa, Toshiya

2018-03-01

We present constraints on the patchy reionization by measuring the trispectrum of the Planck 2015 cosmic microwave background (CMB) temperature anisotropies. The patchy reionization leads to anisotropies in the CMB optical depth, and the statistics of the observed CMB anisotropies is altered. We estimate the trispectrum of the CMB temperature anisotropies to constrain spatial variation of the optical depth. We show that the measured trispectrum is consistent with that from the standard lensed CMB simulation at 2 σ . While no evidence of the patchy reionization is found in the Planck 2015 temperature trispectrum, the CMB constraint on the patchy reionization is significantly improved from previous works. Assuming the analytic bubble-halo model of Wang and Hu (2006), the constraint obtained in this work rules out the typical bubble size at the ionization fraction of ˜0.5 as R ≳10 Mpc . Further, our constraint implies that large-scale B -modes from the patchy reionization are not a significant contamination in detecting the primordial gravitational waves of r ≳0.001 if the B mode induced by the patchy reionization is described by Dvorkin et al. (2009). The CMB trispectrum data starts to provide meaningful constraints on the patchy reionization.

Constraints on patchy reionization from Planck CMB temperature trispectrum

DOE PAGES

Namikawa, Toshiya

2018-03-05

Here, we present constraints on the patchy reionization by measuring the trispectrum of the Planck 2015 cosmic microwave background (CMB) temperature anisotropies. The patchy reionization leads to anisotropies in the CMB optical depth, and the statistics of the observed CMB anisotropies is altered. Here, we estimate the trispectrum of the CMB temperature anisotropies to constrain spatial variation of the optical depth. We show that the measured trispectrum is consistent with that from the standard lensed CMB simulation at 2σ. While no evidence of the patchy reionization is found in the Planck 2015 temperature trispectrum, the CMB constraint on the patchymore » reionization is significantly improved from previous works. Assuming the analytic bubble-halo model of Wang and Hu (2006), the constraint obtained in this work rules out the typical bubble size at the ionization fraction of ~ 0.5 as R ≳ 10 Mpc. Further, our constraint implies that large-scale B -modes from the patchy reionization are not a significant contamination in detecting the primordial gravitational waves of r ≳ 0.001 if the B mode induced by the patchy reionization is described by Dvorkin et al. (2009). The CMB trispectrum data starts to provide meaningful constraints on the patchy reionization.« less

Estimating Noise in the Hydrogen Epoch of Reionization Array

NASA Astrophysics Data System (ADS)

Englund Mathieu, Philip; HERA Team

2017-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope dedicated to observing large scale structure during and prior to the epoch of reionization. Once completed, HERA will have unprecedented sensitivity to the 21-cm signal from hydrogen reionization. This poster will present time- and frequency-subtraction methods and results from a preliminary analysis of the noise characteristics of the nineteen-element pathfinder array.

Planck intermediate results: XLVII. Planck constraints on reionization history

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adam, R.; Aghanim, N.; Ashdown, M.

In this paper, we investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058 ± 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric ormore » an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Δz < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z ≃ 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. Finally, we show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.« less

Planck intermediate results: XLVII. Planck constraints on reionization history

DOE PAGES

Adam, R.; Aghanim, N.; Ashdown, M.; ...

2016-12-12

In this paper, we investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058 ± 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric ormore » an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Δz < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z ≃ 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. Finally, we show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.« less

Large 21-cm signals from AGN-dominated reionization

NASA Astrophysics Data System (ADS)

Kulkarni, Girish; Choudhury, Tirthankar Roy; Puchwein, Ewald; Haehnelt, Martin G.

2017-08-01

We present predictions for the spatial distribution of 21-cm brightness temperature fluctuations from high-dynamic-range simulations for active galactic nucleus (AGN)-dominated reionization histories that have been tested against available Lyα and cosmic microwave background (CMB) data. We model AGNs by extrapolating the observed Mbh - σ relation to high redshifts and assign them ionizing emissivities consistent with recent UV luminosity function measurements. We assess the observability of the predicted spatial 21-cm fluctuations in the late stages of reionization in the limit in which the hydrogen 21-cm spin temperature is significantly larger than the CMB temperature. Our AGN-dominated reionization histories increase the variance of the 21-cm emission by a factor of up to 10 compared to similar reionization histories dominated by faint galaxies, to values close to 100 mK2 at scales accessible to experiments (k ≲ 1 cMpc-1 h). This is lower than the sensitivity reached by ongoing experiments only by a factor of about 2 or less. When reionization is dominated by AGNs, the 21-cm power spectrum is enhanced on all scales due to the enhanced bias of the clustering of the more massive haloes and the peak in the large scale 21-cm power is strongly enhanced and moved to larger scales due to bigger characteristic bubble sizes. AGN-dominated reionization should be easily detectable by Low Frequency Array (and later Hydrogen Epoch of Reionization Array and Phase 1 of the Square Kilometre Array) at their design sensitivity, assuming successful foreground subtraction and instrument calibration. Conversely, these could become the first non-trivial reionization scenarios to be ruled out by 21-cm experiments, thereby constraining the contribution of AGNs to reionization.

Constraining Reionization with the z ˜ 5-6 Lyα Forest Power Spectrum: The Outlook after Planck

NASA Astrophysics Data System (ADS)

Oñorbe, J.; Hennawi, J. F.; Lukić, Z.; Walther, M.

2017-09-01

The latest measurements of cosmic microwave background electron-scattering optical depth reported by Planck significantly reduces the allowed space of {{H}} {{I}} reionization models, pointing toward a later ending and/or less extended phase transition than previously believed. Reionization impulsively heats the intergalactic medium (IGM) to ˜ {10}4 {{K}}, and owing to long cooling and dynamical times in the diffuse gas that are comparable to the Hubble time, memory of reionization heating is retained. Therefore, a late-ending reionization has significant implications for the structure of the z˜ 5{--}6 Lyα forest. Using state-of-the-art hydrodynamical simulations that allow us to vary the timing of reionization and its associated heat injection, we argue that extant thermal signatures from reionization can be detected via the Lyα forest power spectrum at 5< z< 6. This arises because the small-scale cutoff in the power depends not only the the IGM temperature at these epochs, but is also particularly sensitive to the pressure-smoothing scale set by the IGM full thermal history. Comparing our different reionization models with existing measurements of the Lyα forest flux power spectrum at z=5.0{--}5.4, we find that models satisfying Planck’s {τ }e constraint favor a moderate amount of heat injection consistent with galaxies driving reionization, but disfavoring quasar-driven scenarios. We study the feasibility of measuring the flux power spectrum at z≃ 6 using mock quasar spectra and conclude that a sample of ˜10 high-resolution spectra with an attainable signal-to-noise ratio will allow distinguishing between different reionization scenarios.

On modeling and measuring the temperature of the z ∼ 5 intergalactic medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lidz, Adam; Malloy, Matthew, E-mail: alidz@sas.upenn.edu

2014-06-20

The temperature of the low-density intergalactic medium (IGM) at high redshift is sensitive to the timing and nature of hydrogen and He II reionization, and can be measured from Lyman-alpha (Lyα) forest absorption spectra. Since the memory of intergalactic gas to heating during reionization gradually fades, measurements as close as possible to reionization are desirable. In addition, measuring the IGM temperature at sufficiently high redshifts should help to isolate the effects of hydrogen reionization since He II reionization starts later, at lower redshift. Motivated by this, we model the IGM temperature at z ≳ 5 using semi-numeric models of patchymore » reionization. We construct mock Lyα forest spectra from these models and consider their observable implications. We find that the small-scale structure in the Lyα forest is sensitive to the temperature of the IGM even at redshifts where the average absorption in the forest is as high as 90%. We forecast the accuracy at which the z ≳ 5 IGM temperature can be measured using existing samples of high resolution quasar spectra, and find that interesting constraints are possible. For example, an early reionization model in which reionization ends at z ∼ 10 should be distinguishable—at high statistical significance—from a lower redshift model where reionization completes at z ∼ 6. We discuss improvements to our modeling that may be required to robustly interpret future measurements.« less

The mean free path of hydrogen ionizing photons during the epoch of reionization

NASA Astrophysics Data System (ADS)

Rahmati, Alireza; Schaye, Joop

2018-05-01

We use the Aurora radiation-hydrodynamical simulations to study the mean free path (MFP) for hydrogen ionizing photons during the epoch of reionization. We directly measure the MFP by averaging the distance 1 Ry photons travel before reaching an optical depth of unity along random lines-of-sight. During reionization the free paths tend to end in neutral gas with densities near the cosmic mean, while after reionization the end points tend to be overdense but highly ionized. Despite the increasing importance of discrete, over-dense systems, the cumulative contribution of systems with NHI ≲ 1016.5 cm-2 suffices to drive the MFP at z ≈ 6, while at earlier times higher column densities are more important. After reionization the typical size of HI systems is close to the local Jeans length, but during reionization it is much larger. The mean free path for photons originating close to galaxies, {MFP_{gal}}, is much smaller than the cosmic MFP. After reionization this enhancement can remain significant up to starting distances of ˜1 comoving Mpc. During reionization, however, {MFP_{gal}} for distances ˜102 - 103 comoving kpc typically exceeds the cosmic MFP. These findings have important consequences for models that interpret the intergalactic MFP as the distance escaped ionizing photons can travel from galaxies before being absorbed and may cause them to under-estimate the required escape fraction from galaxies, and/or the required emissivity of ionizing photons after reionization.

Cosmic Reionization on Computers: Properties of the Post-reionization IGM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.; Becker, George D.; Fan, Xiaohui

Here, we present a comparison between several observational tests of the post-reionization IGM and the numerical simulations of reionization completed under the Cosmic Reionization On Computers (CROC) project. The CROC simulations match the gap distribution reasonably well, and also provide a good match for the distribution of peak heights, but there is a notable lack of wide peaks in the simulated spectra and the flux PDFs are poorly matched in the narrow redshift interval 5.5 < z < 5.7, with the match at other redshifts being significantly better, albeit not exact. Both discrepancies are related: simulations show more opacity thanmore » the data.« less

Cosmic Reionization on Computers: Properties of the Post-reionization IGM

DOE PAGES

Gnedin, Nickolay Y.; Becker, George D.; Fan, Xiaohui

2017-05-19

Here, we present a comparison between several observational tests of the post-reionization IGM and the numerical simulations of reionization completed under the Cosmic Reionization On Computers (CROC) project. The CROC simulations match the gap distribution reasonably well, and also provide a good match for the distribution of peak heights, but there is a notable lack of wide peaks in the simulated spectra and the flux PDFs are poorly matched in the narrow redshift interval 5.5 < z < 5.7, with the match at other redshifts being significantly better, albeit not exact. Both discrepancies are related: simulations show more opacity thanmore » the data.« less

The Dark Ages of the Universe and hydrogen reionization

NASA Astrophysics Data System (ADS)

Natarajan, Aravind; Yoshida, Naoki

2014-06-01

One of the milestones in cosmic history is the formation of the first luminous objects and hydrogen reionization. The standard theory of cosmic structure formation predicts that the first generation of stars were born about a few hundred million years after the Big Bang. The dark Universe was then lit up once again, and eventually filled with ultraviolet photons emitted from stars, galaxies, and quasars. The exact epoch of the cosmic reionization and the details of the process, even the dominant sources, are not known, except for the fact that the Universe was reionized early on. Signatures of reionization are expected to be imprinted in the cosmic microwave background (CMB) radiation, especially in its large-scale polarization. Future CMB experiments, together with other probes such as the H i 21 cm surveys, will provide rich information on the process of reionization. We review recent studies on reionization. The implications from available observations over a wide range of wavelengths are discussed. Results from state-of-the-art computer simulations are presented. Finally, we discuss the prospects for exploring the first few hundred million years of the cosmic history.

How online counselling can support partners of individuals with problem alcohol or other drug use.

PubMed

Wilson, Samara R; Rodda, Simone; Lubman, Dan I; Manning, Victoria; Yap, Marie B H

2017-07-01

Problematic alcohol and other drug (AOD) use impacts partners heavily, with an increased risk of experiencing domestic violence, financial stressors, health problems and relationship challenges. However, partners often do not seek help or support due to a range of barriers (e.g., shame, stigma, practical constraints). Online counselling may facilitate help-seeking by overcoming many of these barriers, however research is needed to explore what motivates partners to contact online counselling services, their experiences and needs, and how partners can be best supported online. One hundred transcripts of partners of individuals with problem AOD use were sampled from a 24-hour national AOD synchronous online chat counselling service. Descriptive content analysis was used to investigate themes related to help-seeking. Three broad themes, with seven sub-themes, were identified: (i) the reason for accessing online counselling (seeking advice, wanting to talk), (ii) discussing help-seeking and coping processes (past/present help-seeking or coping strategies, barriers and facilitators to seeking help and change), and (iii) planning for future assistance (future planning, treatment preferences). Partners wanted to talk about their concerns with a non-judgemental professional. However, the majority of help-seekers wanted advice and assistance in problem-solving, coping and the process of seeking further help. Future studies need to examine the impact of online help-seeking by partners. Copyright © 2017 Elsevier Inc. All rights reserved.

Reionization Models Classifier using 21cm Map Deep Learning

NASA Astrophysics Data System (ADS)

Hassan, Sultan; Liu, Adrian; Kohn, Saul; Aguirre, James E.; La Plante, Paul; Lidz, Adam

2018-05-01

Next-generation 21cm observations will enable imaging of reionization on very large scales. These images will contain more astrophysical and cosmological information than the power spectrum, and hence providing an alternative way to constrain the contribution of different reionizing sources populations to cosmic reionization. Using Convolutional Neural Networks, we present a simple network architecture that is sufficient to discriminate between Galaxy-dominated versus AGN-dominated models, even in the presence of simulated noise from different experiments such as the HERA and SKA.

Dark-ages reionization and galaxy formation simulation - III. Modelling galaxy formation and the epoch of reionization

NASA Astrophysics Data System (ADS)

Mutch, Simon J.; Geil, Paul M.; Poole, Gregory B.; Angel, Paul W.; Duffy, Alan R.; Mesinger, Andrei; Wyithe, J. Stuart B.

2016-10-01

We introduce MERAXES, a new, purpose-built semi-analytic galaxy formation model designed for studying galaxy growth during reionization. MERAXES is the first model of its type to include a temporally and spatially coupled treatment of reionization and is built upon a custom (100 Mpc)3 N-body simulation with high temporal and mass resolution, allowing us to resolve the galaxy and star formation physics relevant to early galaxy formation. Our fiducial model with supernova feedback reproduces the observed optical depth to electron scattering and evolution of the galaxy stellar mass function between z = 5 and 7, predicting that a broad range of halo masses contribute to reionization. Using a constant escape fraction and global recombination rate, our model is unable to simultaneously match the observed ionizing emissivity at z ≲ 6. However, the use of an evolving escape fraction of 0.05-0.1 at z ˜ 6, increasing towards higher redshift, is able to satisfy these three constraints. We also demonstrate that photoionization suppression of low-mass galaxy formation during reionization has only a small effect on the ionization history of the intergalactic medium. This lack of `self-regulation' arises due to the already efficient quenching of star formation by supernova feedback. It is only in models with gas supply-limited star formation that reionization feedback is effective at regulating galaxy growth. We similarly find that reionization has only a small effect on the stellar mass function, with no observationally detectable imprint at M* > 107.5 M⊙. However, patchy reionization has significant effects on individual galaxy masses, with variations of factors of 2-3 at z = 5 that correlate with environment.

Reionization and CMB non-Gaussianity

NASA Astrophysics Data System (ADS)

Munshi, D.; Corasaniti, P. S.; Coles, P.; Heavens, A.; Pandolfi, S.

2014-08-01

We show how cross-correlating a high-redshift external tracer field, such as the 21-cm neutral hydrogen distribution and product maps involving cosmic microwave background (CMB) temperature and polarization fields, that probe mixed bispectrum involving these fields, can help to determine the reionization history of the Universe, beyond what can be achieved from cross-spectrum analysis. Taking clues from recent studies for the detection of primordial non-Gaussianity, we develop a set of estimators that can study reionization using a power spectrum associated with the bispectrum (or skew-spectrum). We use the matched filtering inherent in this method to investigate different reionization histories. We check to what extent they can be used to rule out various models of reionization and study cross-contamination from different sources such as the lensing of the CMB. The estimators can be fine-tuned to optimize study of a specific reionization history. We consider three different types of tracers in our study, namely: proto-galaxies; 21-cm maps of neutral hydrogen; and quasars. We also consider four alternative models of reionization. We find that the cumulative signal-to-noise ratio (S/N) for detection at ℓmax = 2000 can reach O(70) for cosmic variance limited all-sky experiments. Combining 100 GHz, 143 GHz and 217 GHz channels of the Planck experiment, we find that the S/N lies in the range O(5)-O(35). The S/N depends on the specific choice of a tracer field, and multiple tracers can be effectively used to map out the entire reionization history with reasonable S/N. Contamination from weak lensing is investigated and found to be negligible, and the effects of Thomson scattering from patchy reionization are also considered.

Simulating Cosmic Reionization and Its Observable Consequences

NASA Astrophysics Data System (ADS)

Shapiro, Paul

2017-01-01

I summarize recent progress in modelling the epoch of reionization by large- scale simulations of cosmic structure formation, radiative transfer and their interplay, which trace the ionization fronts that swept across the IGM, to predict observable signatures. Reionization by starlight from early galaxies affected their evolution, impacting reionization, itself, and imprinting the galaxies with a memory of reionization. Star formation suppression, e.g., may explain the observed underabundance of Local Group dwarfs relative to N-body predictions for Cold Dark Matter. I describe CoDa (''Cosmic Dawn''), the first fully-coupled radiation-hydrodynamical simulation of reionization and galaxy formation in the Local Universe, in a volume large enough to model reionization globally but with enough resolving power to follow all the atomic-cooling galactic halos in that volume. A 90 Mpc box was simulated from a constrained realization of primordial fluctuations, chosen to reproduce present-day features of the Local Group, including the Milky Way and M31, and the local universe beyond, including the Virgo cluster. The new RAMSES-CUDATON hybrid CPU-GPU code took 11 days to perform this simulation on the Titan supercomputer at Oak Ridge National Laboratory, with 4096-cubed N-body particles for the dark matter and 4096-cubed cells for the atomic gas and ionizing radiation.

Understanding why women seek abortions in the US

PubMed Central

2013-01-01

Background The current political climate with regards to abortion in the US, along with the economic recession may be affecting women’s reasons for seeking abortion, warranting a new investigation into the reasons why women seek abortion. Methods Data for this study were drawn from baseline quantitative and qualitative data from the Turnaway Study, an ongoing, five-year, longitudinal study evaluating the health and socioeconomic consequences of receiving or being denied an abortion in the US. While the study has followed women for over two full years, it relies on the baseline data which were collected from 2008 through the end of 2010. The sample included 954 women from 30 abortion facilities across the US who responded to two open ended questions regarding the reasons why they wanted to terminate their pregnancy approximately one week after seeking an abortion. Results Women’s reasons for seeking an abortion fell into 11 broad themes. The predominant themes identified as reasons for seeking abortion included financial reasons (40%), timing (36%), partner related reasons (31%), and the need to focus on other children (29%). Most women reported multiple reasons for seeking an abortion crossing over several themes (64%). Using mixed effects multivariate logistic regression analyses, we identified the social and demographic predictors of the predominant themes women gave for seeking an abortion. Conclusions Study findings demonstrate that the reasons women seek abortion are complex and interrelated, similar to those found in previous studies. While some women stated only one factor that contributed to their desire to terminate their pregnancies, others pointed to a myriad of factors that, cumulatively, resulted in their seeking abortion. As indicated by the differences we observed among women’s reasons by individual characteristics, women seek abortion for reasons related to their circumstances, including their socioeconomic status, age, health, parity and marital status. It is important that policy makers consider women’s motivations for choosing abortion, as decisions to support or oppose such legislation could have profound effects on the health, socioeconomic outcomes and life trajectories of women facing unwanted pregnancies. PMID:23829590

The star formation histories of local group dwarf galaxies. II. Searching for signatures of reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisz, Daniel R.; Dolphin, Andrew E.; Skillman, Evan D.

We search for signatures of reionization in the star formation histories (SFHs) of 38 Local Group dwarf galaxies (10{sup 4} < M{sub *} < 10{sup 9} M{sub ☉}). The SFHs are derived from color-magnitude diagrams using archival Hubble Space Telescope/Wide Field Planetary Camera 2 imaging. Only five quenched galaxies (And V, And VI, And XIII, Leo IV, and Hercules) are consistent with forming the bulk of their stars before reionization, when full uncertainties are considered. Observations of 13 of the predicted 'true fossils' identified by Bovill and Ricotti show that only two (Hercules and Leo IV) indicate star formation quenchedmore » by reionization. However, both are within the virial radius of the Milky Way and evidence of tidal disturbance complicates this interpretation. We argue that the late-time gas capture scenario posited by Ricotti for the low mass, gas-rich, and star-forming fossil candidate Leo T is observationally indistinguishable from simple gas retention. Given the ambiguity between environmental effects and reionization, the best reionization fossil candidates are quenched low mass field galaxies (e.g., KKR 25).« less

Observing patchy reionization with future CMB polarization experiments

NASA Astrophysics Data System (ADS)

Roy, A.; Lapi, A.; Spergel, D.; Baccigalupi, C.

2018-05-01

We study the signal from patchy reionization in view of the future high accuracy polarization measurements of the Cosmic Microwave Background (CMB). We implement an extraction procedure of the patchy reionization signal analogous to CMB lensing. We evaluate the signal to noise ratio (SNR) for the future Stage IV (S4) CMB experiment. The signal has a broad peak centered on the degree angular scales, with a long tail at higher multipoles. The CMB S4 experiment can effectively constrain the properties of reionization by measuring the signal on degree scales. The signal amplitude depends on the properties of the structure determining the reionization morphology. We describe bubbles having radii distributed log-normally. The expected S/N is sensitive to the mean bubble radius: bar R=5 Mpc implies S/N ≈ 4, bar R=10 Mpc implies S/N ≈ 20. The spread of the radii distribution strongly affects the integrated SNR, that changes by a factor of 102 when σlnr goes from ln 2 to ln 3. Future CMB experiments will thus place important constraints on the physics of reionization.

Self-shielding of hydrogen in the IGM during the epoch of reionization

NASA Astrophysics Data System (ADS)

Chardin, Jonathan; Kulkarni, Girish; Haehnelt, Martin G.

2018-04-01

We investigate self-shielding of intergalactic hydrogen against ionizing radiation in radiative transfer simulations of cosmic reionization carefully calibrated with Lyα forest data. While self-shielded regions manifest as Lyman-limit systems in the post-reionization Universe, here we focus on their evolution during reionization (redshifts z = 6-10). At these redshifts, the spatial distribution of hydrogen-ionizing radiation is highly inhomogeneous, and some regions of the Universe are still neutral. After masking the neutral regions and ionizing sources in the simulation, we find that the hydrogen photoionization rate depends on the local hydrogen density in a manner very similar to that in the post-reionization Universe. The characteristic physical hydrogen density above which self-shielding becomes important at these redshifts is about nH ˜ 3 × 10-3 cm-3, or ˜20 times the mean hydrogen density, reflecting the fact that during reionization photoionization rates are typically low enough that the filaments in the cosmic web are often self-shielded. The value of the typical self-shielding density decreases by a factor of 3 between redshifts z = 3 and 10, and follows the evolution of the average photoionization rate in ionized regions in a simple fashion. We provide a simple parameterization of the photoionization rate as a function of density in self-shielded regions during the epoch of reionization.

Self-shielding of hydrogen in the IGM during the epoch of reionization

NASA Astrophysics Data System (ADS)

Chardin, Jonathan; Kulkarni, Girish; Haehnelt, Martin G.

2018-07-01

We investigate self-shielding of intergalactic hydrogen against ionizing radiation in radiative transfer simulations of cosmic reionization carefully calibrated with Lyα forest data. While self-shielded regions manifest as Lyman limit systems in the post-reionization Universe, here we focus on their evolution during reionization (redshifts z = 6-10). At these redshifts, the spatial distribution of hydrogen-ionizing radiation is highly inhomogeneous, and some regions of the Universe are still neutral. After masking the neutral regions and ionizing sources in the simulation, we find that the hydrogen photoionization rate depends on the local hydrogen density in a manner very similar to that in the post-reionization Universe. The characteristic physical hydrogen density above which self-shielding becomes important at these redshifts is about nH ˜ 3 × 10-3 cm-3, or ˜20 times the mean hydrogen density, reflecting the fact that during reionization photoionization rates are typically low enough that the filaments in the cosmic web are often self-shielded. The value of the typical self-shielding density decreases by a factor of 3 between redshifts z = 3 and 10, and follows the evolution of the average photoionization rate in ionized regions in a simple fashion. We provide a simple parametrization of the photoionization rate as a function of density in self-shielded regions during the epoch of reionization.

Cosmic Dawn Intensity Mapper (CDIM): a New Probe of Cosmic Dawn and Reionization

NASA Astrophysics Data System (ADS)

Chang, Tzu-Ching; CDIM Team

2018-01-01

The Cosmic Dawn Intensity Mapper, CDIM, is a NASA Probe-class Mission Study currently under study. CDIM is designed to be a near-IR survey instrument optimized for Cosmic Dawn and reionization sciences, answering critical questions on how and when galaxies and quasars first formed, the history of metal build-up, and the history and topology of reionization, among other questions. CDIM will provide R=300 spectroscopic imaging over ~10 sq. degree instantaneous field of view at 1 arcsecond resolution, over the wavelength range of 0.75 to 7.5 mm. A two-tiered wedding-cake survey will consist of a shallow tier spanning close to 300 deg2 and a deep tier of about 25 deg2. CDIM survey data will allow us to (i) determine spectroscopic redshifts of WFIRST-detected Lyman-break galaxies (LBGs) out to a redshift of 10; (ii) establish the environmental dependence of star formation during reionization through clustering and other environmental measurements; (iii) establish the metal abundance of first-light galaxies during reionization over two decades of stellar mass by spectrally separating NII from Hα, and detecting both Hβ and [OIII]; (iv) measure 3D tomographic intensity fluctuations during reionization in both Lyα at z > 6 and Hα at 0 < z < 10; and (v) cross-correlating intensity fluctuations with 21-cm data to establish the topology of reionization bubbles.

Constraining the Epoch of Reionization from the Observed Properties of the High-z Universe

NASA Astrophysics Data System (ADS)

Salvador-Solé, Eduard; Manrique, Alberto; Guzman, Rafael; Rodríguez Espinosa, José Miguel; Gallego, Jesús; Herrero, Artemio; Mas-Hesse, J. Miguel; Marín Franch, Antonio

2017-01-01

We combine observational data on a dozen independent cosmic properties at high-z with the information on reionization drawn from the spectra of distant luminous sources and the cosmic microwave background (CMB) to constrain the interconnected evolution of galaxies and the intergalactic medium since the dark ages. The only acceptable solutions are concentrated in two narrow sets. In one of them reionization proceeds in two phases: a first one driven by Population III stars, completed at z˜ 10, and after a short recombination period a second one driven by normal galaxies, completed at z˜ 6. In the other set both kinds of sources work in parallel until full reionization at z˜ 6. The best solution with double reionization gives excellent fits to all the observed cosmic histories, but the CMB optical depth is 3σ larger than the recent estimate from the Planck data. Alternatively, the best solution with single reionization gives less good fits to the observed star formation rate density and cold gas mass density histories, but the CMB optical depth is consistent with that estimate. We make several predictions, testable with future observations, that should discriminate between the two reionization scenarios. As a byproduct our models provide a natural explanation to some characteristic features of the cosmic properties at high-z, as well as to the origin of globular clusters.

Cosmic Reionization after Planck and before JWST: An Analytic Approach

NASA Astrophysics Data System (ADS)

Madau, Piero

2017-12-01

The reionization of cosmic hydrogen marks a critical juncture in the history of structure formation. Here we present a new formulation of the standard reionization equation for the evolution of the volume-averaged H II fraction that is more consistent with the accepted conceptual model of inhomogeneous intergalactic absorption. The revised equation explicitly accounts for the presence of the optically thick “Lyman-limit systems” that are known to determine the mean-free path of ionizing radiation after overlap. Integration of this equation provides a better characterization of the timing of reionization by smoothly linking the pre-overlap with the post-overlap phases of such a process. We confirm the validity of the quasi-instantaneous approximation as a predictor of reionization completion/maintenance and discuss new insights on the sources of cosmic reionization using the improved formalism. A constant emission rate into the intergalactic medium (IGM) of three Lyman continuum (LyC) photons per atom per gigayear leads to a reionization history that is consistent with a number of observational constraints on the ionization state of the z = 5–9 universe. While star-forming galaxies can dominate the reionization process if the luminosity-weighted fraction of LyC photons that escape into the IGM, {f}{esc}, exceeds 15% (for a faint magnitude cut-off of the galaxy UV luminosity function of {M}{lim}=-13 and a LyC photon yield per unit 1500 Å luminosity of {ξ }{ion}={10}25.3 {{erg}}-1 {Hz}), simple models where the product of the two unknowns {f}{esc}{ξ }{ion} is not evolving with redshift fail to reproduce the changing neutrality of the IGM observed at these epochs.

Constraining the contribution of active galactic nuclei to reionization

NASA Astrophysics Data System (ADS)

Hassan, Sultan; Davé, Romeel; Mitra, Sourav; Finlator, Kristian; Ciardi, Benedetta; Santos, Mario G.

2018-01-01

Recent results have suggested that active galactic nuclei (AGN) could provide enough photons to reionize the Universe. We assess the viability of this scenario using a semi-numerical framework for modelling reionization, to which we add a quasar contribution by constructing a Quasar Halo Occupancy Distribution (QHOD) based on Giallongo et al. observations. Assuming a constant QHOD, we find that an AGN-only model cannot simultaneously match observations of the optical depth τe, neutral fraction and ionizing emissivity. Such a model predicts τe too low by ∼2σ relative to Planck constraints, and reionizes the Universe at z ≲ 5. Arbitrarily increasing the AGN emissivity to match these results yields a strong mismatch with the observed ionizing emissivity at z ∼ 5. If we instead assume a redshift-independent AGN luminosity function yielding an emissivity evolution like that assumed in Madau & Haardt model, then we can match τe albeit with late reionization; however, such evolution is inconsistent with observations at z ∼ 4-6 and poorly motivated physically. These results arise because AGN are more biased towards massive haloes than typical reionizing galaxies, resulting in stronger clustering and later formation times. AGN-dominated models produce larger ionizing bubbles that are reflected in ∼×2 more 21 cm power on all scales. A model with equal part galaxies and AGN contribution is still (barely) consistent with observations, but could be distinguished using next-generation 21 cm experiments such as Hydrogen Epoch of Reionization Array and SKA-low. We conclude that, even with recent claims of more faint AGN than previously thought, AGN are highly unlikely to dominate the ionizing photon budget for reionization.

Cosmic Dawn (CoDa): the First Radiation-Hydrodynamics Simulation of Reionization and Galaxy Formation in the Local Universe

NASA Astrophysics Data System (ADS)

Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul R.; Aubert, Dominique; Iliev, Ilian T.; Teyssier, Romain; Yepes, Gustavo; Choi, Jun-Hwan; Sullivan, David; Knebe, Alexander; Gottlöber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda; Stranex, Timothy

2016-12-01

Cosmic reionization by starlight from early galaxies affected their evolution, thereby impacting reionization itself. Star formation suppression, for example, may explain the observed underabundance of Local Group dwarfs relative to N-body predictions for cold dark matter. Reionization modelling requires simulating volumes large enough [˜ (100 Mpc)3] to sample reionization `patchiness', while resolving millions of galaxy sources above ˜108 M⊙ combining gravitational and gas dynamics with radiative transfer. Modelling the Local Group requires initial cosmological density fluctuations pre-selected to form the well-known structures of the Local Universe today. Cosmic Dawn (`CoDa') is the first such fully coupled, radiation-hydrodynamics simulation of reionization of the Local Universe. Our new hybrid CPU-GPU code, RAMSES-CUDATON, performs hundreds of radiative transfer and ionization rate-solver timesteps on the GPUs for each hydro-gravity timestep on the CPUs. CoDa simulated (91Mpc)3 with 40963 particles and cells, to redshift 4.23, on ORNL supercomputer Titan, utilizing 8192 cores and 8192 GPUs. Global reionization ended slightly later than observed. However, a simple temporal rescaling which brings the evolution of ionized fraction into agreement with observations also reconciles ionizing flux density, cosmic star formation history, CMB electron scattering optical depth and galaxy UV luminosity function with their observed values. Photoionization heating suppressed the star formation of haloes below ˜2 × 109 M⊙, decreasing the abundance of faint galaxies around MAB1600 = [-10, -12]. For most of reionization, star formation was dominated by haloes between 1010-1011 M⊙ , so low-mass halo suppression was not reflected by a distinct feature in the global star formation history. Intergalactic filaments display sheathed structures, with hot envelopes surrounding cooler cores, but do not self-shield, unlike regions denser than 100 <ρ>.

Strong Lens Models for Massive Galaxy Clusters in the Reionization Lensing Cluster Survey

NASA Astrophysics Data System (ADS)

Cerny, Catherine; Sharon, Keren; Coe, Dan A.; Paterno-Mahler, Rachel; Jones, Christine; Czakon, Nicole G.; Umetsu, Keiichi; Stark, Daniel; Bradley, Larry D.; Trenti, Michele; Johnson, Traci; Bradac, Marusa; Dawson, William; Rodney, Steven A.; Strolger, Louis-Gregory; RELICS Team

2017-01-01

We present strong lensing models for five galaxy clusters from the Planck SZ cluster catalog as a part of the Reionization Lensing Cluster Survey (RELICS), a program that seeks to constrain the galaxy luminosity function past z~9 by conducting a wide field survey of massive galaxy clusters with HST (GO-14096, PI: Coe). The strong gravitational lensing effects of these clusters significantly magnify background galaxies, which enhances our ability to discover the large numbers of high redshift galaxies at z~9-12 needed to create a representative sample. We use strong lensing models for these clusters to study their mass distribution and magnification, which allows us to quantify the lensing effect on the background galaxies. These models can then be utilized in the RELICS survey in order to identify high redshift galaxy candidates that may be lensed by the clusters. The intrinsic properties of these galaxy candidates can be derived by removing the lensing effect as predicted by our models, which will meet the science goals of the RELICS survey. We use HST WFC3 and ACS imaging to create lensing models for the clusters RXC J0142.9+4438, ACO-2537, ACO-2163, RXCJ2211.7-0349, and ACT-CLJ0102-49151.

Joint Estimation of the Epoch of Reionization Power Spectrum and Foregrounds

NASA Astrophysics Data System (ADS)

Sims, Peter; Pober, Jonathan

2018-01-01

Bright astrophysical foregrounds present a significant impediment to the detection of redshifted 21-cm emission from the Epoch of Reionization on large spatial scales. In this talk I present a framework for the joint modeling of the power spectral contamination by astrophysical foregrounds and the power spectrum of the Epoch of Reionization. I show how informative priors on the power spectral contamination by astrophysical foregrounds at high redshifts, where emission from both the Epoch of Reionization and its foregrounds is present in the data, can be obtained through analysis of foreground-only emission at lower redshifts. Finally, I demonstrate how, by using such informative foreground priors, joint modeling can be employed to mitigate bias in estimates of the power spectrum of the Epoch of Reionization signal and, in particular, to enable recovery of more robust power spectral estimates on large spatial scales.

Cosmic reionization on computers. II. Reionization history and its back-reaction on early galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.; Kaurov, Alexander A., E-mail: gnedin@fnal.gov, E-mail: kaurov@uchicago.edu

We compare the results from several sets of cosmological simulations of cosmic reionization, produced under the Cosmic Reionization On Computers project, with existing observational data on the high-redshift Lyα forest and the abundance of Lyα emitters. We find good consistency with the observational measurements and previous simulation work. By virtue of having several independent realizations for each set of numerical parameters, we are able to explore the effect of cosmic variance on observable quantities. One unexpected conclusion we are forced into is that cosmic variance is unusually large at z > 6, with both our simulations and, most likely, observationalmore » measurements still not fully converged for even such basic quantities as the average Gunn-Peterson optical depth or the volume-weighted neutral fraction. We also find that reionization has little effect on the early galaxies or on global cosmic star formation history, because galaxies whose gas content is affected by photoionization contain no molecular (i.e., star-forming) gas in the first place. In particular, measurements of the faint end of the galaxy luminosity function by the James Webb Space Telescope are unlikely to provide a useful constraint on reionization.« less

Psychological Help-Seeking Attitudes and Barriers to Help-Seeking in Young People in Turkey

ERIC Educational Resources Information Center

Koydemir, Selda; Erel, Ozge; Yumurtaci, Duygu; Sahin, Gozde Nur

2010-01-01

This qualitative research sought to understand the needs of Turkish university students related to adjustment to university, the sources they seek help from, their attitudes about and barriers to psychological help-seeking. Data analysis of interview transcriptions from 15 undergraduates identified several themes. Interpersonal problems,…

Reionization and Cosmic Dawn: theory and simulations

NASA Astrophysics Data System (ADS)

Mesinger, Andrei

2018-05-01

We highlight recent progress in the sophistication and diversification of the simulations of cosmic dawn and reionization. The application of these modeling tools to recent observations has allowed us narrow down the timing of reionization. The midpoint of reionization is constrained to z = 7.6-0.7+0.8 (1 σ), with the strongest constraints coming from the optical depth to the CMB measured with the Planck satellite and the first detection of ongoing reionization from the spectra of the z = 7.1 QSOs ULASJ1120+0641. However, we still know virtually nothing about the astrophysical sources during the first billion years. The revolution in our understanding will be led by upcoming interferometric observations of the cosmic 21-cm signal. The properties of the sources and sinks of UV and X-ray photons are encoded in the 3D patterns of the signal. The development of Bayesian parameter recovery techniques, which tap into the wealth of the 21-cm signal, will soon usher in an era of precision astrophysical cosmology.

Local Group ultra-faint dwarf galaxies in the reionization era

NASA Astrophysics Data System (ADS)

Weisz, Daniel R.; Boylan-Kolchin, Michael

2017-07-01

Motivated by the stellar fossil record of Local Group (LG) dwarf galaxies, we show that the star-forming ancestors of the faintest ultra-faint dwarf galaxies (UFDs; MV ˜ -2 or M⋆ ˜ 102 at z = 0) had ultraviolet (UV) luminosities of MUV ˜ -3 to -6 during reionization (z ˜ 6-10). The existence of such faint galaxies has substantial implications for early epochs of galaxy formation and reionization. If the faint-end slopes of the UV luminosity functions (UVLFs) during reionization are steep (α ≲ -2) to MUV ˜ -3, then (I) the ancestors of UFDs produced >50 per cent of UV flux from galaxies; (II) galaxies can maintain reionization with escape fractions that are more than two times lower than currently adopted values; (III) direct Hubble Space Telescope and James Webb Space Telescope observations may detect only ˜10-50 per cent of the UV light from galaxies; and (IV) the cosmic star formation history increases by ≳ 4-6 at z ≳ 6. Significant flux from UFDs, and resultant tensions with LG dwarf galaxy counts, is reduced if the high-redshift UVLF turns over. Independent of the UVLF shape, the existence of a large population of UFDs requires a non-zero luminosity function to MUV ˜ -3 during reionization.

Interpreting HST observations with simulations of reionization: the ionizing photon budget and the decline of Lyman-alpha emission in z>6 dropouts

NASA Astrophysics Data System (ADS)

D'Aloisio, Anson

2017-08-01

In recent years, HST surveys such as CANDELS, HUDF, BoRG/HIPPIES, ERS, and the Frontier Fields, have made possible the first robust measurements of the rest-frame UV luminosity function of z =6-10 galaxies, spanning much of the redshift range over which reionization likely occurred. These measurements provide an estimate of the galactic ionizing photon output, addressing the critical question of whether these galaxies could have reionized the Universe. In addition, follow-up spectroscopy has measured the fraction of these galaxies that show Lyman-alpha emission. Interestingly, a dramatic decrease in this fraction above z 6 has been observed, and this evolution has (controversially) been interpreted as evidence that much of reionization happened over z=6-8 (as intergalactic neutral gas leads to large damping wings that scatter the Lyman-alpha line). The clumpiness of the IGM and how it self shields to ionizing photons impacts whether the observed population of galaxies can reionize the Universe, as well as the interpretation of the evolving Lyman-alpha emitter fraction. We propose to run fully coupled radiative-hydrodynamics simulations that are the first to resolve the evaporation of small structures by passing ionization fronts and, hence, to accurately assess the level of clumpiness and self-shielding from the IGM. Our study will nail down the clumping factor used to assess whether the observed population of galaxies can drive reionization, and it will address whether neutral self-shielding clumps in recently reionized regions can scatter galaxies' Lyman-alpha lines.

"We're going through a lot of struggles that people don't even know about": the need to understand African American males' help-seeking for mental health on multiple levels.

PubMed

Lindsey, Michael A; Marcell, Arik V

2012-09-01

Young adult Black males face challenges related to addressing their mental health needs, yet there is much more to know about their help-seeking experiences. Twenty-seven Black males, recruited from four community-based organizations, participated in four focus groups to explore perceptions of help-seeking for mental health. Identified themes, which function at individual, social network, community, and health care system levels, may facilitate or hinder Black males' mental health help-seeking. Themes included (a) "taking care of it oneself" as opposed to seeking help from someone; (b) issues engaging sources of help, including the ability to trust providers or the relationship closeness with social network members; and (c) "tipping points" that activate help-seeking to avert crises. Study findings provide initial evidence about the importance of addressing mental health interventions for Black males on multiple levels beyond the individual including engaging men's social supports, community, and the health care system.

Probing HeII Reionization at z>3.5 with Resolved HeII Lyman Alpha Forest Spectra

NASA Astrophysics Data System (ADS)

Worseck, Gabor

2017-08-01

The advent of GALEX and COS have revolutionized our view of HeII reionization, the final major phase transition of the intergalactic medium. COS spectra of the HeII Lyman alpha forest have confirmed with high confidence the high HeII transmission that signifies the completion of HeII reionization at z 2.7. However, the handful of z>3.5 quasars observed to date show a set of HeII transmission 'spikes' and larger regions with non-zero transmission that suggest HeII reionization was well underway by z=4. This is in striking conflict with predictions from state-of-the-art radiative transfer simulations of a HeII reionization driven by bright quasars. Explaining these measurements may require either faint quasars or more exotic sources of hard photons at z>4, with concomitant implications for HI reionization. However, many of the observed spikes are unresolved in G140L spectra and are significantly impacted by Poisson noise. Current data cannot reliably probe the ionization state of helium at z>3.5.We request 41 orbits to obtain science-grade G130M spectra of the two UV-brightest HeII-transmitting QSOs at z>3.5 to confirm and resolve their HeII transmission spikes as an unequivocal test of early HeII reionization. These spectra are complemented by recently obtained data from 8m telescopes: (1) Echelle spectra of the coeval HI Lya forest to map the underlying density field that modulates the HeII absorption, and (2) Our dedicated survey for foreground QSOs that may source the HeII transmission. Our recent HST programs revealed the only two viable targets to resolve the z>3.5 HeII Lyman alpha forest, and to conclusively solve this riddle.

Cosmic reionization after Planck II: contribution from quasars

NASA Astrophysics Data System (ADS)

Mitra, Sourav; Choudhury, T. Roy; Ferrara, Andrea

2018-01-01

In the light of the recent Planck downward revision of the electron scattering optical depth, and of the discovery of a faint active galactic nuclei (AGN) population at z > 4, we reassess the actual contribution of quasars to cosmic reionization. To this aim, we extend our previous Markov Chain Monte Carlo based data-constrained semi-analytic reionization model and study the role of quasars on global reionization history. We find that the quasars can alone reionize the Universe only for models with very high AGN emissivities at high redshift. These models are still allowed by the recent cosmic microwave background data and most of the observations related to H I reionization. However, they predict an extended and early He II reionization ending at z ≳ 4 and a much slower evolution in the mean He II Ly-α forest opacity than what the actual observation suggests. Thus, when we further constrain our model against the He II Ly-α forest data, this AGN-dominated scenario is found to be clearly ruled out at 2σ limits. The data seems to favour a standard two-component picture where quasar contributions become negligible at z ≳ 6 and a non-zero escape fraction of ∼ 10 per cent is needed from early-epoch galaxies. For such models, mean neutral hydrogen fraction decreases to ∼10-4 at z = 6.2 from ∼0.8 at z = 10.0 and helium becomes doubly ionized at much later time, z ∼ 3. We find that these models are as well in good agreement with the observed thermal evolution of IGM as opposed to models with very high AGN emissivities.

Reionization of the Milky Way, M31, and their satellites - I. Reionization history and star formation

NASA Astrophysics Data System (ADS)

Dixon, Keri L.; Iliev, Ilian T.; Gottlöber, Stefan; Yepes, Gustavo; Knebe, Alexander; Libeskind, Noam; Hoffman, Yehuda

2018-06-01

Observations of the Milky Way (MW), M31, and their vicinity, known as the Local Group (LG), can provide clues about the sources of reionization. We present a suite of radiative transfer simulations based on initial conditions provided by the Constrained Local UniversE Simulations (CLUES) project that are designed to recreate the Local Universe, including a realistic MW-M31 pair and a nearby Virgo. Our box size (91 Mpc) is large enough to incorporate the relevant sources of ionizing photons for the LG. We employ a range of source models, mimicking the potential effects of radiative feedback for dark matter haloes between {˜ }10^8 and 10^9 M_{⊙}. Although the LG mostly reionizes in an inside-out fashion, the final 40 per cent of its ionization shows some outside influence. For the LG satellites, we find no evidence that their redshift of reionization is related to the present-day mass of the satellite or the distance from the central galaxy. We find that fewer than 20 per cent of present-day satellites for MW and M31 have undergone any star formation prior to the end of global reionization. Approximately 5 per cent of these satellites could be classified as fossils, meaning the majority of star formation occurred at these early times. The more massive satellites have more cumulative star formation prior to the end of global reionization, but the scatter is significant, especially at the low-mass end. Present-day mass and distance from the central galaxy are poor predictors for the presence of ancient stellar populations in satellite galaxies.

Self-consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations

DOE PAGES

Oñorbe, Jose; Hennawi, Joseph F.; Lukić, Zarija

2017-03-08

The ultraviolet background (UVB) emitted by quasars and galaxies governs the ionization and thermal state of the intergalactic medium (IGM), regulates the formation of high-redshift galaxies, and is thus a key quantity for modeling cosmic reionization. The vast majority of cosmological hydrodynamical simulations implement the UVB via a set of spatially uniform photoionization and photoheating rates derived from UVB synthesis models. In this paper, we show that simulations using canonical UVB rates reionize and, perhaps more importantly, spuriously heat the IGM, much earlier (more » $$z\\sim 15$$) than they should. This problem arises because at $$z\\gt 6$$, where observational constraints are nonexistent, the UVB amplitude is far too high. We introduce a new methodology to remedy this issue, and we generate self-consistent photoionization and photoheating rates to model any chosen reionization history. Following this approach, we run a suite of hydrodynamical simulations of different reionization scenarios and explore the impact of the timing of reionization and its concomitant heat injection on the thermal state of the IGM. We present a comprehensive study of the pressure smoothing scale of IGM gas, illustrating its dependence on the details of both hydrogen and helium reionization, and argue that it plays a fundamental role in interpreting Lyα forest statistics and the thermal evolution of the IGM. The premature IGM heating we have uncovered implies that previous work has likely dramatically overestimated the impact of photoionization feedback on galaxy formation, which sets the minimum halo mass able to form stars at high redshifts. Finally, we make our new UVB photoionization and photoheating rates publicly available for use in future simulations.« less

New Constraints on the Hard Ionizing Photon Budget and the Lifetime and Obscuration of Quasars During the Epoch of Helium Reionization

NASA Astrophysics Data System (ADS)

Davies, Frederick

2017-08-01

The epoch of helium reionization was a major milestone in the history of the Universe, a direct consequence of supermassive black hole growth and the cumulative output of hard ionizing photons by quasars. Our observations of the He II Ly-alpha forest with HST/COS in 26 quasar sightlines show strong fluctuations at z 3, consistent with our state-of-the-art simulations of the He II reionization epoch. However, our detection of transmission at z > 3.5 is inconsistent with all He II reionization models. Resolving this puzzle requires an extensive parameter study of He II reionization, which we propose to carry out using our fast, efficient simulations. The He II Ly-alpha forest is also sensitive to the effect of quasar radiation illuminating the intergalactic medium, known as the proximity effect. We have performed an ambitious ground-based imaging and spectroscopic survey for z 3 quasars in the foreground of HeII sightlines observed with HST/COS, and statistically detected the transverse proximity effect for the first time. The strength of this effect depends on both the quasar lifetime and the opening angle of quasar emission (or the fraction of obscured quasars), and we propose to use our He II reionization simulations to interpret this new measurement. Finally, the line-of-sight proximity effect due to the background quasar provides an independent constraint on the quasar lifetime. Our preliminary comparison of He II spectra to our radiative transfer simulations suggests a quasar lifetime > 10 Myr. We propose to use our He II reionization simulations to model this diverse set of observations and fully capitalize on the far-UV legacy of HST.

Epoch of reionization 21 cm forecasting from MCMC-constrained semi-numerical models

NASA Astrophysics Data System (ADS)

Hassan, Sultan; Davé, Romeel; Finlator, Kristian; Santos, Mario G.

2017-06-01

The recent low value of Planck Collaboration XLVII integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavouring extended reionization scenarios. This will have a significant impact on the 21 cm power spectrum. Using a semi-numerical framework, we improve our model from instantaneous to include time-integrated ionization and recombination effects, and find that this leads to more sudden reionization. It also yields larger H II bubbles that lead to an order of magnitude more 21 cm power on large scales, while suppressing the small-scale ionization power. Local fluctuations in the neutral hydrogen density play the dominant role in boosting the 21 cm power spectrum on large scales, while recombinations are subdominant. We use a Monte Carlo Markov chain approach to constrain our model to observations of the star formation rate functions at z = 6, 7, 8 from Bouwens et al., the Planck Collaboration XLVII optical depth measurements and the Becker & Bolton ionizing emissivity data at z ˜ 5. We then use this constrained model to perform 21 cm forecasting for Low Frequency Array, Hydrogen Epoch of Reionization Array and Square Kilometre Array in order to determine how well such data can characterize the sources driving reionization. We find that the Mock 21 cm power spectrum alone can somewhat constrain the halo mass dependence of ionizing sources, the photon escape fraction and ionizing amplitude, but combining the Mock 21 cm data with other current observations enables us to separately constrain all these parameters. Our framework illustrates how the future 21 cm data can play a key role in understanding the sources and topology of reionization as observations improve.

Near-field limits on the role of faint galaxies in cosmic reionization

NASA Astrophysics Data System (ADS)

Boylan-Kolchin, Michael; Bullock, James S.; Garrison-Kimmel, Shea

2014-09-01

Reionizing the Universe with galaxies appears to require significant star formation in low-mass haloes at early times, while local dwarf galaxy counts tell us that star formation has been minimal in small haloes around us today. Using simple models and the ELVIS simulation suite, we show that reionization scenarios requiring appreciable star formation in haloes with Mvir ≈ 108 M⊙ at z = 8 are in serious tension with galaxy counts in the Local Group. This tension originates from the seemingly inescapable conclusion that 30-60 haloes with Mvir > 108 M⊙ at z = 8 will survive to be distinct bound satellites of the Milky Way at z = 0. Reionization models requiring star formation in such haloes will produce dozens of bound galaxies in the Milky Way's virial volume today (and 100-200 throughout the Local Group), each with ≳105 M⊙ of old stars (≳13 Gyr). This exceeds the stellar mass function of classical Milky Way satellites today, even without allowing for the (significant) post-reionization star formation observed in these galaxies. One possible implication of these findings is that star formation became sharply inefficient in haloes smaller than ˜109 M⊙ at early times, implying that the high-z luminosity function must break at magnitudes brighter than is often assumed (at MUV ≃ -14). Our results suggest that the James Webb Space Telescope (and possibly even the Hubble Space Telescope with the Frontier Fields) may realistically detect the faintest galaxies that drive reionization. It remains to be seen how these results can be reconciled with the most sophisticated simulations of early galaxy formation at present, which predict substantial star formation in Mvir ˜ 108 M⊙ haloes during the epoch of reionization.

Self-consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oñorbe, Jose; Hennawi, Joseph F.; Lukić, Zarija

The ultraviolet background (UVB) emitted by quasars and galaxies governs the ionization and thermal state of the intergalactic medium (IGM), regulates the formation of high-redshift galaxies, and is thus a key quantity for modeling cosmic reionization. The vast majority of cosmological hydrodynamical simulations implement the UVB via a set of spatially uniform photoionization and photoheating rates derived from UVB synthesis models. In this paper, we show that simulations using canonical UVB rates reionize and, perhaps more importantly, spuriously heat the IGM, much earlier (more » $$z\\sim 15$$) than they should. This problem arises because at $$z\\gt 6$$, where observational constraints are nonexistent, the UVB amplitude is far too high. We introduce a new methodology to remedy this issue, and we generate self-consistent photoionization and photoheating rates to model any chosen reionization history. Following this approach, we run a suite of hydrodynamical simulations of different reionization scenarios and explore the impact of the timing of reionization and its concomitant heat injection on the thermal state of the IGM. We present a comprehensive study of the pressure smoothing scale of IGM gas, illustrating its dependence on the details of both hydrogen and helium reionization, and argue that it plays a fundamental role in interpreting Lyα forest statistics and the thermal evolution of the IGM. The premature IGM heating we have uncovered implies that previous work has likely dramatically overestimated the impact of photoionization feedback on galaxy formation, which sets the minimum halo mass able to form stars at high redshifts. Finally, we make our new UVB photoionization and photoheating rates publicly available for use in future simulations.« less

Spatial Fluctuations of the Intergalactic Temperature-Density Relation After Hydrogen Reionization

NASA Astrophysics Data System (ADS)

Keating, Laura C.; Puchwein, Ewald; Haehnelt, Martin G.

2018-04-01

The thermal state of the post-reionization IGM is sensitive to the timing of reionization and the nature of the ionizing sources. We have modelled here the thermal state of the IGM in cosmological radiative transfer simulations of a realistic, extended, spatially inhomogeneous hydrogen reionization process, carefully calibrated with Lyα forest data. We compare these with cosmological simulations run using a spatially homogeneous ionizing background. The simulations with a realistic growth of ionized regions and a realistic spread in reionization redshifts show, as expected, significant spatial fluctuations in the temperature-density relation (TDR) of the post-reionization IGM. The most recently ionized regions are hottest and exhibit a flatter TDR. In simulations consistent with the average TDR inferred from Lyα forest data, these spatial fluctuations have a moderate but noticeable effect on the statistical properties of the Lyα opacity of the IGM at z ˜ 4 - 6. This should be taken into account in accurate measurements of the thermal properties of the IGM and the free-streaming of dark matter from Lyα forest data in this redshift range. The spatial variations of the TDR predicted by our simulations are, however, smaller by about a factor two than would be necessary to explain the observed large spatial opacity fluctuations on large (≥ 50 h-1 comoving Mpc) scales at z ≳ 5.5.

Spatial fluctuations of the intergalactic temperature-density relation after hydrogen reionization

NASA Astrophysics Data System (ADS)

Keating, Laura C.; Puchwein, Ewald; Haehnelt, Martin G.

2018-07-01

The thermal state of the post-reionization IGM is sensitive to the timing of reionization and the nature of the ionizing sources. We have modelled here the thermal state of the IGM in cosmological radiative transfer simulations of a realistic, extended, spatially inhomogeneous hydrogen reionization process, carefully calibrated with Ly α forest data. We compare these with cosmological simulations run using a spatially homogeneous ionizing background. The simulations with a realistic growth of ionized regions and a realistic spread in reionization redshifts show, as expected, significant spatial fluctuations in the temperature-density relation (TDR) of the post-reionization IGM. The most recently ionized regions are hottest and exhibit a flatter TDR. In simulations consistent with the average TDR inferred from Ly α forest data, these spatial fluctuations have a moderate but noticeable effect on the statistical properties of the Ly α opacity of the IGM at z ˜ 4-6. This should be taken into account in accurate measurements of the thermal properties of the IGM and the free-streaming of dark matter from Ly α forest data in this redshift range. The spatial variations of the TDR predicted by our simulations are, however, smaller by about a factor of 2 than would be necessary to explain the observed large spatial opacity fluctuations on large (≥50 h-1 comoving Mpc) scales atz ≳ 5.5.

Cosmic reionization on computers. Mean and fluctuating redshifted 21 CM signal

DOE PAGES

Kaurov, Alexander A.; Gnedin, Nickolay Y.

2016-06-20

We explore the mean and fluctuating redshifted 21 cm signal in numerical simulations from the Cosmic Reionization On Computers project. We find that the mean signal varies between about ±25 mK. Most significantly, we find that the negative pre-reionization dip at z ~ 10–15 only extends tomore » $$\\langle {\\rm{\\Delta }}{T}_{B}\\rangle \\sim -25\\,{\\rm{mK}}$$, requiring substantially higher sensitivity from global signal experiments that operate in this redshift range (EDGES-II, LEDA, SCI-HI, and DARE) than has often been assumed previously. We also explore the role of dense substructure (filaments and embedded galaxies) in the formation of the 21 cm power spectrum. We find that by neglecting the semi-neutral substructure inside ionized bubbles, the power spectrum can be misestimated by 25%–50% at scales k ~ 0.1–1h Mpc –1. Furthermore, this scale range is of particular interest, because the upcoming 21 cm experiments (Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization, Hydrogen Epoch of Reionization Array) are expected to be most sensitive within it.« less

Cosmic Reionization On Computers. Mean and Fluctuating Redshifted 21 cm Signal

NASA Astrophysics Data System (ADS)

Kaurov, Alexander A.; Gnedin, Nickolay Y.

2016-06-01

We explore the mean and fluctuating redshifted 21 cm signal in numerical simulations from the Cosmic Reionization On Computers project. We find that the mean signal varies between about ±25 mK. Most significantly, we find that the negative pre-reionization dip at z ˜ 10-15 only extends to < {{Δ }}{T}B> ˜ -25 {{mK}}, requiring substantially higher sensitivity from global signal experiments that operate in this redshift range (EDGES-II, LEDA, SCI-HI, and DARE) than has often been assumed previously. We also explore the role of dense substructure (filaments and embedded galaxies) in the formation of the 21 cm power spectrum. We find that by neglecting the semi-neutral substructure inside ionized bubbles, the power spectrum can be misestimated by 25%-50% at scales k ˜ 0.1-1h Mpc-1. This scale range is of particular interest, because the upcoming 21 cm experiments (Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization, Hydrogen Epoch of Reionization Array) are expected to be most sensitive within it.

IslandFAST: A Semi-numerical Tool for Simulating the Late Epoch of Reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Yidong; Chen, Xuelei; Yue, Bin

2017-08-01

We present the algorithm and main results of our semi-numerical simulation, islandFAST, which was developed from 21cmFAST and designed for the late stage of reionization. The islandFAST simulation predicts the evolution and size distribution of the large-scale underdense neutral regions (neutral islands), and we find that the late Epoch of Reionization proceeds very fast, showing a characteristic scale of the neutral islands at each redshift. Using islandFAST, we compare the impact of two types of absorption systems, i.e., the large-scale underdense neutral islands versus small-scale overdense absorbers, in regulating the reionization process. The neutral islands dominate the morphology of themore » ionization field, while the small-scale absorbers dominate the mean-free path of ionizing photons, and also delay and prolong the reionization process. With our semi-numerical simulation, the evolution of the ionizing background can be derived self-consistently given a model for the small absorbers. The hydrogen ionization rate of the ionizing background is reduced by an order of magnitude in the presence of dense absorbers.« less

Cosmic reionization on computers. Mean and fluctuating redshifted 21 CM signal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaurov, Alexander A.; Gnedin, Nickolay Y.

We explore the mean and fluctuating redshifted 21 cm signal in numerical simulations from the Cosmic Reionization On Computers project. We find that the mean signal varies between about ±25 mK. Most significantly, we find that the negative pre-reionization dip at z ~ 10–15 only extends tomore » $$\\langle {\\rm{\\Delta }}{T}_{B}\\rangle \\sim -25\\,{\\rm{mK}}$$, requiring substantially higher sensitivity from global signal experiments that operate in this redshift range (EDGES-II, LEDA, SCI-HI, and DARE) than has often been assumed previously. We also explore the role of dense substructure (filaments and embedded galaxies) in the formation of the 21 cm power spectrum. We find that by neglecting the semi-neutral substructure inside ionized bubbles, the power spectrum can be misestimated by 25%–50% at scales k ~ 0.1–1h Mpc –1. Furthermore, this scale range is of particular interest, because the upcoming 21 cm experiments (Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization, Hydrogen Epoch of Reionization Array) are expected to be most sensitive within it.« less

Illuminating the Universe's Ignition

DOE PAGES

Gedenk, Eric

2016-06-24

This paper tells the story of how a research team based at the University of Texas at Austin used supercomputing resources at the US Department of Energy's (DOE's) Oak Ridge National Laboratory to create the first fully coupled simulation of the reionization of our universe's local group. The team's models helped researchers understand how reionization helped form the universe as we know it today, predict the impact of dwarf galaxies on reionization, and set the stage for simulating larger volumes of the universe in greater detail.

Towards constraints on the epoch of reionization: A phenomenological approach

NASA Astrophysics Data System (ADS)

Malloy, Matthew

Based on observations of the early Universe, we know that shortly after the Big Bang, the Universe was composed almost entirely of neutral hydrogen and neutral helium. However, observations of nearby quasars suggest that the gas between galaxies today is neutral to less than one part in 104 . Thus, it must be the case that some process occurred that stripped the electrons from almost all atoms in the intergalactic medium. Understanding the timing and nature of this process, dubbed ''reionization'', is one of the great outstanding problems in astrophysics and cosmology today. In this thesis, we develop several methods for utilizing existing and future measurements in order to make progress toward this end. We begin by proposing two novel approaches for searching for signatures of underlying neutral hydrogen in the Lyalpha and Lybeta forest of distant quasars. We show that, if the Universe is >5% neutral at z ~ 5.5, then damping-wing absorption from neutral hydrogen and absorption from primordial deuterium should leave observable imprints in the Lyalpha and Lybeta forest, respectively. Furthermore, the presence of neutral islands should qualitatively alter the size distribution of absorbed regions. We continue by discussing the ability for the intergalactic medium to retain a thermal memory of the reionization process at redshifts z ~ 5, which in turn affects the small-scale structure in the Lyalpha forest. Motivated by this, we model the temperature of the intergalactic medium after reionization and develop a temperature measurement technique that should be able to distinguish between scenarios where reionization ends at z ~ 6 and at z ~ 10. Lastly, we turn our attention to 21-cm observations during reionization. We demonstrate that, while precise mapping of 21-cm emission from neutral hydrogen should be infeasible by first and second generation interferometers, it may be possible to make crude maps of the reionization process and identify individual ionized regions. This would provide us with direct confirmation that we are observing reionization and provide information regarding its timing and the nature of the ionizing sources.

The duration of reionization constrains the ionizing sources

NASA Astrophysics Data System (ADS)

Sharma, Mahavir; Theuns, Tom; Frenk, Carlos

2018-06-01

We investigate how the nature of the galaxies that reionized the Universe affects the duration of reionization. We contrast two sets of models: one in which galaxies on the faint side of the luminosity function dominate the ionizing emissivity, and a second in which the galaxies on the bright side of the luminosity function dominate. The faint end of the luminosity function evolves slowly, therefore the transition from mostly neutral to mostly ionized state takes a much longer time in the first set of models compared to the second. Existing observational constraints on the duration of this transition are relatively weak, but taken at face value prefer the model in which galaxies on the bright side play a major role. Measurements of the kinetic Sunyaev-Zeldovich effect in the cosmic microwave background from the epoch of reionization also point in the same direction.

Reionization and its imprint of the cosmic microwave background

NASA Technical Reports Server (NTRS)

Dodelson, Scott; Jubas, Jay M.

1995-01-01

Early reionization changes the pattern of anisotropies expected in the cosmic microwave backgrond. To explore these changes, we derive from first principles the equations governing anisotropies, focusing on the interactions of photons with electrons. Vishniac (1987) claimed that second-order terms can be large in a reionized universe, so we derive equations correct to second order in the perturbations. There are many more second-order terms than were considered by Vishniac. To understand the basic physics involved, we present a simple analytic approximation to the first-order equation. Then, turning to the second order equation, we show that the Vishniac term is indeed the only important one. We also present numerical results for a variety of ionization histories (in a standard cold dark matter universe) and show quantitatively how the signal in several experiments depends on the ionization history. The most pronounced indication of a reionized universe would be seen in very small scale experiments; the expected signal in the Owens Valley experiment is smaller by a factor of order 10 if the last scattering surface is at a redshift z approximately = 100 as it would be if the universe were reionized very early. On slightly larger scales, the expected signal in a reionized universe is smaller than it would be with standard recombination, but only a factor of 2 or so. The signal is even smaller in these experiments in the intermediate case where some photons last scattered at the standard recombination epoch.

Cosmic Dawn Intensity Mapper

NASA Astrophysics Data System (ADS)

Cooray, Asantha

2018-01-01

Cosmic Dawn Intensity Mapper (CDIM) is a 1.0m-class infrared telescope capable of three-dimensional spectro-imaging observations over the wavelength range of 0.75 to 7.5 microns, at a spectral resolving power at or better than 300. This will be achieved with linear variablefilters (LVFs) and a large field-of-view (FoV). The survey strategy using spacecraft operations following a shift and stare mode will result in more than 1300 independent narrow-band spectral images of the sky at a given location. Currently prioritized science programs, taking over three-years of a five-year mission, will be accomplished with a two-tiered wedding-cake survey with the shallowest spanning close to 300 sq. degrees and the deepest tier of about 25 sq. degrees.The remaining two-years could be used for additional survey programs (the wide tier can be expanded to 1000 sq. degrees) or for use by the astronomical community through a General Observing (GO) campaign. CDIM survey data will allow us to (i) establish the initial mass function of stars in galaxies present during reionization, (ii) definitively address AGN/quasar contribution to the reionization photon budget; (iii) establish the environmental dependence of star-formation during reionization through clustering and other environmental measurements; (iv) establish the metal abundance of first-light galaxies during reionization over two decades of stellar mass; (v) measure 3D intensity fluctuations during reionization in both Ly-alpha and H-alpha; and (vi) combine intensity fluctuations with 21-cm data to establish the topology of reionization bubbles.

On the faint-end of the high-z galaxy luminosity function

NASA Astrophysics Data System (ADS)

Yue, Bin; Ferrara, Andrea; Xu, Yidong

2016-12-01

Recent measurements of the luminosity function (LF) of galaxies in the Epoch of Reionization (EoR, z ≳ 6) indicate a very steep increase of the number density of low-mass galaxies populating the LF faint-end. However, as star formation in low-mass haloes can be easily depressed or even quenched by ionizing radiation, a turnover is expected at some faint UV magnitudes. Using a physically motivated analytical model, we quantify reionization feedback effects on the LF faint-end shape. We find that if reionization feedback is neglected, the power-law Schechter parametrization characterizing the LF faint-end remains valid up to absolute UV magnitude ˜-9. If instead radiative feedback is strong enough that quenches star formation in haloes with circular velocity smaller than 50 km s-1, the LF starts to drop at absolute UV magnitude ˜-15, I.e. slightly below the detection limits of current (unlensed) surveys at z ˜ 5. The LFs may rise again at higher absolute UV magnitude, where, as a result of interplay between reionization process and galaxy formation, most of the galaxy light is from relic stars formed before the EoR. We suggest that the galaxy number counts data, particularly in lensed fields, can put strong constraints on reionization feedback. In models with stronger reionization feedback, stars in galaxies with absolute UV magnitude higher than ˜-13 and smaller than ˜-8 are typically older. Hence, the stellar age-UV magnitude relation can be used as an alternative feedback probe.

Help seeking in a support group for recipients of implantable cardioverter defibrillators and their support persons.

PubMed

Dickerson, S S; Posluszny, M; Kennedy, M C

2000-01-01

To understand shared meanings of help-seeking experiences in support groups of people with implantable cardioverter defibrillator (ICD) and their support persons. ICD support group at an urban medical center. Fifteen individuals with ICD and 9 support persons. Six related themes and 1 constitutive pattern emerged. Themes included hearing and telling stories, help seeking encouraged by triggers, seeking meaningful information, forming a therapeutic friendship through group camaraderie, gaining assistance from the facilitator, and the sharing of a similar view by support persons. The constitutive pattern is coping with the possibility of death. Health care providers may recommend storytelling as the central mechanism of interactions in support groups that assist in coping with daily anxieties of living with an ICD. Nurses would be appropriate facilitators to guide discussion, to provide technical information, and to promote anticipatory guidance in coping with potential firing events.

A Thematic Analysis of Edwin L. Godkin's Editorials in the "Nation," 1865-1899.

ERIC Educational Resources Information Center

Lee, Richard W.

This thematic analysis of Edward L. Godkin's editorials appearing in the "Nation" seeks to reveal the major themes on which he wrote and then, by quantitative analysis, to provide some order to the themes and to study the interaction of the themes. Five hundred and twelve editorials, written over a period of 35 years and representing…

Seeking systemic change: risk and protective factors affecting low-income urban youth.

PubMed

Meyerson, David A; Grant, Kathryn E

2014-01-01

This themed issue presents five articles tackling the topic of risk and protective processes affecting children and adolescents living in urban poverty. Through their research, the authors seek understanding of the particular challenges that low-income urban youth face, with the ultimate goal of understanding how best to intervene at various levels of the ecological system. Within this broad theme, studies examine specific stressors, mediators, and moderators that impact the mental health of youth living in urban poverty. The final article presents a data-driven, community-based intervention for this population.

Probing reionization with the cross-power spectrum of 21 cm and near-infrared radiation backgrounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Xiao-Chun, E-mail: xcmao@bao.ac.cn

2014-08-01

The cross-correlation between the 21 cm emission from the high-redshift intergalactic medium and the near-infrared (NIR) background light from high-redshift galaxies promises to be a powerful probe of cosmic reionization. In this paper, we investigate the cross-power spectrum during the epoch of reionization. We employ an improved halo approach to derive the distribution of the density field and consider two stellar populations in the star formation model: metal-free stars and metal-poor stars. The reionization history is further generated to be consistent with the electron-scattering optical depth from cosmic microwave background measurements. Then, the intensity of the NIR background is estimatedmore » by collecting emission from stars in first-light galaxies. On large scales, we find that the 21 cm and NIR radiation backgrounds are positively correlated during the very early stages of reionization. However, these two radiation backgrounds quickly become anti-correlated as reionization proceeds. The maximum absolute value of the cross-power spectrum is |Δ{sub 21,NIR}{sup 2}|∼10{sup −4} mK nW m{sup –2} sr{sup –1}, reached at ℓ ∼ 1000 when the mean fraction of ionized hydrogen is x-bar{sub i}∼0.9. We find that Square Kilometer Array can measure the 21 cm-NIR cross-power spectrum in conjunction with mild extensions to the existing CIBER survey, provided that the integration time independently adds up to 1000 and 1 hr for 21 cm and NIR observations, and that the sky coverage fraction of the CIBER survey is extended from 4 × 10{sup –4} to 0.1. Measuring the cross-correlation signal as a function of redshift provides valuable information on reionization and helps confirm the origin of the 'missing' NIR background.« less

Quasars at the Cosmic Dawn: effects on Reionization properties in cosmological simulations

NASA Astrophysics Data System (ADS)

Garaldi, Enrico; Compostella, Michele; Porciani, Cristiano

2018-05-01

We study a model of cosmic reionization where quasars (QSOs) are the dominant source of ionizing photons at all relevant epochs. We employ a suite of adaptive hydrodynamical simulations post-processed with a multi-wavelength Monte Carlo radiative-transfer code and calibrate them in order to accurately reproduce the observed quasar luminosity function and emissivity evolution. Our results show that the QSO-only model fails in reproducing key observables linked to the Helium reionization, as the temperature evolution of the inter-galactic medium (IGM) and the HeII effective optical depth in synthetic Lyα spectra. Nevertheless, we find hints that an increased quasar contribution can explain recent measurements of a large inhomogeneity in the IGM at redshift z ~ 5. Finally, we devise a method capable of constraining the QSOs contribution to the reionization from the properties of the HeII Lyα forest at z ~ 3.5.

Patchy screening of the cosmic microwave background by inhomogeneous reionization

NASA Astrophysics Data System (ADS)

Gluscevic, Vera; Kamionkowski, Marc; Hanson, Duncan

2013-02-01

We derive a constraint on patchy screening of the cosmic microwave background from inhomogeneous reionization using off-diagonal TB and TT correlations in WMAP-7 temperature/polarization data. We interpret this as a constraint on the rms optical-depth fluctuation Δτ as a function of a coherence multipole LC. We relate these parameters to a comoving coherence scale, of bubble size RC, in a phenomenological model where reionization is instantaneous but occurs on a crinkly surface, and also to the bubble size in a model of “Swiss cheese” reionization where bubbles of fixed size are spread over some range of redshifts. The current WMAP data are still too weak, by several orders of magnitude, to constrain reasonable models, but forthcoming Planck and future EPIC data should begin to approach interesting regimes of parameter space. We also present constraints on the parameter space imposed by the recent results from the EDGES experiment.

Evolution of the Quasar Luminosity Function: Implications for EoR-21cm

NASA Astrophysics Data System (ADS)

Kulkarni, Girish; Choudhury, Tirthankar Roy; Puchwein, Ewald; Haehnelt, Martin G.

2018-05-01

We present predictions for the spatial distribution of 21 cm brightness temperature fluctuations from high-dynamic-range simulations for AGN-dominated reionization histories that have been tested against available Lyα and CMB data. We model AGN by extrapolating the observed Mbh-σ relation to high redshifts and assign them ionizing emissivities consistent with recent UV luminosity function measurements. AGN-dominated reionization histories increase the variance of the 21 cm emission by a factor of up to ten compared to similar reionization histories dominated by faint galaxies, to values close to 100 mK2 at scales accessible to experiments (k <~ 1 cMpc-1h). This is lower than the sensitivity reached by ongoing experiments by only a factor of about two or less. AGN dominated reionization should be easily detectable by LOFAR (and later HERA and SKA1) at their design sensitivity.

Parametrizing the Reionization History with the Redshift Midpoint, Duration, and Asymmetry

NASA Astrophysics Data System (ADS)

Trac, Hy

2018-05-01

A new parametrization of the reionization history is presented to facilitate robust comparisons between different observations and with theory. The evolution of the ionization fraction with redshift can be effectively captured by specifying the midpoint, duration, and asymmetry parameters. Lagrange interpolating functions are then used to construct analytical curves that exactly fit corresponding ionization points. The shape parametrizations are excellent matches to theoretical results from radiation-hydrodynamic simulations. The comparative differences for reionization observables are: ionization fraction | {{Δ }}{x}{{i}}| ≲ 0.03, 21 cm brightness temperature | {{Δ }}{T}{{b}}| ≲ 0.7 {mK}, Thomson optical depth | {{Δ }}τ | ≲ 0.001, and patchy kinetic Sunyaev–Zel’dovich angular power | {{Δ }}{D}{\\ell }| ≲ 0.1 μ {{{K}}}2. This accurate and flexible approach will allow parameter-space studies and self-consistent constraints on the reionization history from 21 cm, cosmic microwave background (CMB), and high-redshift galaxies and quasars.

Influence of ∼7 keV sterile neutrino dark matter on the process of reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudakovskyi, Anton; Iakubovskyi, Dmytro, E-mail: rudakovskyi@gmail.com, E-mail: iakubovskyi@nbi.ku.dk

2016-06-01

Recent reports of a weak unidentified emission line at ∼3.5 keV found in spectra of several matter-dominated objects may give a clue to resolve the long-standing problem of dark matter. One of the best physically motivated particle candidate able to produce such an extra line is sterile neutrino with the mass of ∼7 keV . Previous works show that sterile neutrino dark matter with parameters consistent with the new line measurement modestly affects structure formation compared to conventional cold dark matter scenario. In this work, we concentrate for the first time on contribution of the sterile neutrino dark matter ablemore » to produce the observed line at ∼3.5 keV, to the process of reionization. By incorporating dark matter power spectra for ∼7 keV sterile neutrinos into extended semi-analytical 'bubble' model of reionization we obtain that such sterile neutrino dark matter would produce significantly sharper reionization compared to widely used cold dark matter models, impossible to 'imitate' within the cold dark matter scenario under any reasonable choice of our model parameters, and would have a clear tendency of lowering both the redshift of reionization and the electron scattering optical depth (although the difference is still below the existing model uncertainties). Further dedicated studies of reionization (such as 21 cm measurements or studies of kinetic Sunyaev-Zeldovich effect) will thus be essential for reconstruction of particle candidate responsible the ∼3.5 keV line.« less

What Can Galaxies Tell Us About The Epoch of Reionization?

NASA Astrophysics Data System (ADS)

Mason, Charlotte; GLASS, BoRG

2018-01-01

The reionization of neutral hydrogen in the intergalactic medium (IGM) in the universe's first billion years (z>6) was likely driven by the first stars and galaxies, and its history encodes information about their properties. But the timeline of reionization is not well-measured and it is still unclear whether galaxies alone can produce the required ionizing photons. I will describe two key ways in which galaxies at our current observational frontiers can constrain reionization.One tool is the UV luminosity function (LF), which traces the evolution of star-forming galaxies and their ionizing photons. I will describe a Bayesian technique to account for gravitational lensing magnification bias in galaxy surveys to produce accurate LFs. I will then describe a simple, but powerful, model for LF evolution and its implications for reionization and z>10 galaxy surveys with JWST. Secondly, Lyman alpha (Lya) emission from galaxies is a potential probe of the IGM ionization state as Lya photons are strongly attenuated by neutral hydrogen, but requires disentangling physics on pc to Gpc scales. I will introduce a new forward-modeling Bayesian framework which combines cosmological IGM simulations with models of interstellar medium conditions to infer the IGM neutral fraction from observations of Lya emission. I will present our new measurement of the neutral fraction at z~7 and place it in the context of other constraints of the reionization history. I will describe ongoing efforts to build larger samples of Lya emitting galaxies for more accurate measurements with the HST survey GLASS, and will describe future prospects with JWST.

Using Philosophical Liberalism and Philosophical Conservatism as an Organizing Theme in the First Half of the American History Survey

ERIC Educational Resources Information Center

Morris, Richard J.

2009-01-01

Since approximately 1970, many historians have been seeking a unifying theme for the American History Survey. Early in the twentieth century, Progressive historians identified class conflict as the main theme in American History, but during the 1950s and 1960s, this view was challenged by the Consensus Schools' assertion that Americans have always…

Comparing cosmological hydrodynamic simulations with observations of high- redshift galaxy formation

NASA Astrophysics Data System (ADS)

Finlator, Kristian Markwart

We use cosmological hydrodynamic simulations to study the impact of outflows and radiative feedback on high-redshift galaxies. For outflows, we consider simulations that assume (i) no winds, (ii) a "constant-wind" model in which the mass-loading factor and outflow speed are constant, and (iii) "momentum-driven" winds in which both parameters vary smoothly with mass. In order to treat radiative feedback, we develop a moment-based radiative transfer technique that operates in both post-processing and coupled radiative hydrodynamic modes. We first ask how outflows impact the broadband spectral energy distributions (SEDs) of six observed reionization-epoch galaxies. Simulations reproduce five regardless of the outflow prescription, while the sixth suggests an unusually bursty star formation history. We conclude that (i) simulations broadly account for available constraints on reionization-epoch galaxies, (ii) individual SEDs do not constrain outflows, and (iii) SED comparisons efficiently isolate objects that challenge simulations. We next study how outflows impact the galaxy mass metallicity relation (MZR). Momentum-driven outflows uniquely reproduce observations at z = 2. In this scenario, galaxies obey two equilibria: (i) The rate at which a galaxy processes gas into stars and outflows tracks its inflow rate; and (ii) The gas enrichment rate owing to star formation balances the dilution rate owing to inflows. Combining these conditions indicates that the MZR is dominated by the (instantaneous) variation of outflows with mass, with more-massive galaxies driving less gas into outflows per unit stellar mass formed. Turning to radiative feedback, we use post-processing simulations to study the topology of reionization. Reionization begins in overdensities and then "leaks" directly into voids, with filaments reionizing last owing to their high density and low emissivity. This result conflicts with previous findings that voids ionize last. We argue that it owes to the uniqely-biased emissivity field produced by our star formation prescriptions, which have previously been shown to reproduce numerous post-reionization constraints. Finally, preliminary results from coupled radiative hydrodynamic simulations indicate that reionization suppresses the star formation rate density by at most 10-20% by z = 5. This is much less than previous estimates, which we attribute to our unique reionization topology although confirmation will have to await more detailed modeling.

Work or retirement: Exploration of the experiences of Iranian retired nurses.

PubMed

Nobahar, Monir; Ahmadi, Fazlollah; Alhani, Fatemah; Khoshknab, Masood Fallahi

2015-01-01

According to recent studies, the level of international interest in bridge employment, as return to work after retirement, has been growing. This study aimed to explore the experiences of retired nurses in Iran with regard to making a decision about whether or not to seek bridge employment. A qualitative study using a content analysis approach was conducted in an urban area of Iran. Semi-structured interviews were held with 20 Iranian male and female retired nurses chosen using purposive sampling. During the data analysis, two main themes were identified as the participants' thoughts supporting the decision of seeking bridge employment. The first theme was entitled motivational factors with categories of ``serving the society,'' ``maintaining and promoting health,'' ``tendency toward flexible work,'' and ``maintaining the role and activity.'' The second theme was entitled forcing factors with categories of ``ardent desire to work (pluralistic ignorance)'' and ``financial need.' ' While some Iranian retired nurses were not motivated to seek work for health reasons, most preferred to return to work after retirement. They were motivated to seek bridge employment out of a desire to serve the society, to promote their own physical and mental health, to continue to use their expertise and maintain the worker role, and because of financial needs and perceived societal expectations. Nurses seeking employment later in life tended to look for job flexibility and less stressful work. Therefore, the management of bridge employment by healthcare system authorities can be useful in making use of the invaluable experiences of retired nurses.

PRECISE MEASUREMENT OF THE REIONIZATION OPTICAL DEPTH FROM THE GLOBAL 21 cm SIGNAL ACCOUNTING FOR COSMIC HEATING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fialkov, Anastasia; Loeb, Abraham, E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

2016-04-10

As a result of our limited data on reionization, the total optical depth for electron scattering, τ, limits precision measurements of cosmological parameters from the Cosmic Microwave Background (CMB). It was recently shown that the predicted 21 cm signal of neutral hydrogen contains enough information to reconstruct τ with sub-percent accuracy, assuming that the neutral gas was much hotter than the CMB throughout the entire epoch of reionization (EoR). Here we relax this assumption and use the global 21 cm signal alone to extract τ for realistic X-ray heating scenarios. We test our model-independent approach using mock data for amore » wide range of ionization and heating histories and show that an accurate measurement of the reionization optical depth at a sub-percent level is possible in most of the considered scenarios even when heating is not saturated during the EoR, assuming that the foregrounds are mitigated. However, we find that in cases where heating sources had hard X-ray spectra and their luminosity was close to or lower than what is predicted based on low-redshift observations, the global 21 cm signal alone is not a good tracer of the reionization history.« less

Approaching reionization from two directions: high-redshift Lyman-alpha emitters and local analogs

NASA Astrophysics Data System (ADS)

Bagley, Micaela

2018-01-01

The dark ages that followed the recombination of the universe ended with the appearance of metal-free stars and the subsequent formation of numerous low-mass, metal-poor galaxies. The collective ionizing background from these newly-forming galaxies is thought to be responsible for the reionization of the diffuse hydrogen in the intergalactic medium between redshifts 10 and 6.5. The progression of the reionization history depends on the nature of these first sources -- their number densities, luminosities, clustering, and production rates of ionizing photons -- which is currently the subject of considerable observational and theoretical efforts.I will present results of a two-pronged approach to studying the Epoch of Reionization: a systematic search for Lyman-alpha emitting galaxies at redshifts greater than 6, and an analysis of high S/N spectra of a sample of local galaxies that are potential analogs to those responsible for the reionization. Selected for their large [OIII]/[OII] ratios and high H-alpha equivalent widths, the local galaxies have very low masses and are consistent with photoionization by stars with effective temperatures of 10^5 K. Both the emission lines and continua of the spectra are spatially extended, allowing for an analysis of galaxy properties such as gas temperature, elemental abundance, and ionizing power at different radii.

Probing Reionization at z≥7 with HST's Near-Infrared Grisms

NASA Astrophysics Data System (ADS)

Borello Schmidt, Kasper

2015-08-01

The epoch of reionization, i.e. the transition of the IGM from neutral to fully ionized, is essential for our understanding of the evolution of the Universe and the formation of the first stars and galaxies. The first results at z≤ 7 suggest that the reionization happened in a patchy, rather than smooth, fashion. It is still unclear whether galaxies at z≥7 prefer a patchy reionization scenario as well. The Grism Lens-Amplified Survey from Space (GLASS) has obtained spectra of ten thousands of objects in and behind 10 massive galaxy clusters, including the six Hubble Frontier Fields. Coaming the Hubble grism spectroscopy from GLASS results in 100s of spectra of z≥7 galaxy candidates. Taking advantage of the lensing magnification from the foreground clusters, the GLASS spectra reaches unprecedented depths in the near-infrared with flux limits below 10-18 erg/s/cm2. This has resulted in several Lyα detections at z˜7, tight limits on the emission line fluxes for non-detections, and the equivalent width distribution of Lyα in the very earlier Universe. Taking advantage of the extensive spectroscopic samples of z≥7 galaxies from GLASS, I will show how these samples can give us and unprecedented view of the cosmic reionization at z≥7.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yang; Li, Si-Yu; Li, Yong-Ping

The study of reionization history plays an important role in understanding the evolution of our universe. It is commonly believed that the intergalactic medium (IGM) in our universe are fully ionized today, however the reionizing process remains to be mysterious. A simple instantaneous reionization process is usually adopted in modern cosmology without direct observational evidence. However, the history of ionization fraction, x{sub e}(z) will influence CMB observables and constraints on optical depth τ. With the mocked future data sets based on featured reionization model, we find the bias on τ introduced by instantaneous model can not be neglected. In thismore » paper, we study the cosmic reionization history in a model independent way, the so called principle component analysis (PCA) method, and reconstruct x{sub e} (z) at different redshift z with the data sets of Planck, WMAP 9 years temperature and polarization power spectra, combining with the baryon acoustic oscillation (BAO) from galaxy survey and type Ia supernovae (SN) Union 2.1 sample respectively. The results show that reconstructed x{sub e}(z) is consistent with instantaneous behavior, however, there exists slight deviation from this behavior at some epoch. With PCA method, after abandoning the noisy modes, we get stronger constraints, and the hints for featured x{sub e}(z) evolution could become a little more obvious.« less

Sexually explicit racialised media targeting men who have sex with men online: a content analysis of high-risk behaviour depicted in online advertisements.

PubMed

White, Jaclyn M; Dunham, Emilia; Rowley, Blake; Reisner, Sari L; Mimiaga, Matthew J

2015-01-01

Sexually explicit media may perpetuate racial and sexual norms among men who have sex with men. While men may be exposed to sexually explicit media in the online settings where they seek sex with other men, no studies to our knowledge have explored the relationship between the racial and sexual content of advertisements appearing in these spaces. In 2011, using a detailed codebook, 217 sexually explicit advertisements on a male sex-seeking website were coded for themes, actor characteristics and sexual acts depicted. Multivariable logistic regression models examined the association between skin colour, theme, sexual acts and condomless sex acts. Nearly half (45%) featured a 'thug' theme (a style emphasising Black masculinity/hip-hop culture), 21% featured a college theme and 44% featured condomless sex. Advertisements featuring only Black men, advertisements featuring Black men with men of other skin tones and advertisements depicting a thug theme were positively associated with depictions of condomless sex. Online sexually explicit advertisements featuring Black themes and actors more frequently depicted condomless sex than advertisements with White men alone. Future research should examine whether depictions of Black men engaging in condomless sex in online advertisements influence the sexual norms and cognitions of Black men who have sex with men and their partners.

Sexually explicit racialised media targeting men who have sex with men online: A content analysis of high-risk behaviour depicted in online advertisements

PubMed Central

White, Jaclyn M.; Dunham, Emilia; Rowley, Blake; Reisner, Sari L.; Mimiaga, Matthew J.

2015-01-01

Sexually explicit media may perpetuate racial and sexual norms among men who have sex with men. While men may be exposed to sexually explicit media in the online settings where they seek sex with other men, no studies to our knowledge have explored the relationship between the racial and sexual content of advertisements appearing in these spaces. In 2011, 217 sexually explicit advertisements on a male sex-seeking website were coded for themes, actor characteristics, and sexual acts depicted using a detailed codebook. Multivariable logistic regression models examined the association between skin colour, theme, sexual acts, and condomless sex acts. Nearly half (45%) featured a ‘thug’ theme (style emphasising Black masculinity/hip-hop culture), 21% featured a college theme, and 44% featured condomless sex. Ads featuring only Black men, ads featuring Black men with men of other skin tones, and ads depicting a thug theme were positively associated with depictions of condomless sex. Online sexually explicit ads featuring Black themes and actors more frequently depicted risky sex than ads with White men alone. Future research should examine whether risky depictions of Black men in online ads influence the sexual norms and cognitions of Black men who have sex with men and their partners. PMID:25891135

The accuracy of seminumerical reionization models in comparison with radiative transfer simulations

NASA Astrophysics Data System (ADS)

Hutter, Anne

2018-06-01

We have developed a modular seminumerical code that computes the time and spatially dependent ionization of neutral hydrogen (H I), neutral (He I), and single-ionized helium (He II) in the intergalactic medium (IGM). The model accounts for recombinations and provides different descriptions for the photoionization rate that are used to calculate the residual H I fraction in ionized regions. We compare different seminumerical reionization schemes to a radiative transfer (RT) simulation. We use the RT simulation as a benchmark, and find that the seminumerical approaches produce similar H II and He II morphologies and power spectra of the H I 21 cm signal throughout reionization. As we do not track partial ionization of He II, the extent of the double-ionized helium (He III) regions is consistently smaller. In contrast to previous comparison projects, the ionizing emissivity in our seminumerical scheme is not adjusted to reproduce the redshift evolution of the RT simulation, but directly derived from the RT simulation spectra. Among schemes that identify the ionized regions by the ratio of the number of ionization and absorption events on different spatial smoothing scales, we find those that mark the entire sphere as ionized when the ionization criterion is fulfilled to result in significantly accelerated reionization compared to the RT simulation. Conversely, those that flag only the central cell as ionized yield very similar but slightly delayed redshift evolution of reionization, with up to 20 per cent ionizing photons lost. Despite the overall agreement with the RT simulation, our results suggest that constraining ionizing emissivity-sensitive parameters from seminumerical galaxy formation-reionization models are subject to photon nonconservation.

Reionization of Hydrogen and Helium by Early Stars and Quasars

NASA Astrophysics Data System (ADS)

Wyithe, J. Stuart B.; Loeb, Abraham

2003-04-01

We compute the reionization histories of hydrogen and helium caused by the ionizing radiation fields produced by stars and quasars. For the quasars we use a model based on halo-merger rates that reproduces all known properties of the quasar luminosity function at high redshifts. The less constrained properties of the ionizing radiation produced by stars are modeled with two free parameters: (i) a transition redshift, ztran, above which the stellar population is dominated by massive, zero-metallicity stars and below which it is dominated by a Scalo mass function; and (ii) the product of the escape fraction of stellar ionizing photons from their host galaxies and the star formation efficiency, fescf*. We constrain the allowed range of these free parameters at high redshifts on the basis of the lack of the H I Gunn-Peterson trough at z<~6 and the upper limit on the total intergalactic optical depth for electron scattering, τes<0.18, from recent cosmic microwave background (CMB) experiments. We find that quasars ionize helium by a redshift z~4, but cannot reionize hydrogen by themselves before z~6. A major fraction of the allowed combinations of fescf* and ztran leads to an early peak in the ionized fraction because of the presence of metal-free stars at high redshifts. This sometimes results in two reionization epochs, namely, an early H II or He III overlap phase followed by recombination and a second overlap phase. Even if early overlap is not achieved, the peak in the visibility function for scattering of the CMB often coincides with the early ionization phase rather than with the actual reionization epoch. Consequently, τes does not correspond directly to the reionization redshift. We generically find values of τes>~7%, which should be detectable by the MAP satellite.

Observing the Earliest Galaxies: Looking for the Sources of Reionization

NASA Astrophysics Data System (ADS)

Illingworth, Garth

2015-04-01

Systematic searches for the earliest galaxies in the reionization epoch finally became possible in 2009 when the Hubble Space Telescope was updated with a powerful new infrared camera during the final Shuttle servicing mission SM4 to Hubble. The reionization epoch represents the last major phase transition of the universe and was a major event in cosmic history. The intense ultraviolet radiation from young star-forming galaxies is increasingly considered to be the source of the photons that reionized intergalactic hydrogen in the period between the ``dark ages'' (the time before the first stars and galaxies at about 100-200 million years after the Big Bang) and the end of reionization around 800-900 million years. Yet finding and measuring the earliest galaxies in this era of cosmic dawn has proven to a challenging task, even with Hubble's new infrared camera. I will discuss the deep imaging undertaken by Hubble and the remarkable insights that have accrued from the imaging datasets taken over the last decade on the Hubble Ultra-Deep Field (HUDF, HUDF09/12) and other regions. The HUDF datasets are central to the story and have been assembled into the eXtreme Deep Field (XDF), the deepest image ever from Hubble data. The XDF, when combined with results from shallower wide-area imaging surveys (e.g., GOODS, CANDELS) and with detections of galaxies from the Frontier Fields, has provided significant insights into the role of galaxies in reionization. Yet many questions remain. The puzzle is far from being fully solved and, while much will done over the next few years, the solution likely awaits the launch of JWST. NASA/STScI Grant HST-GO-11563.

The accuracy of semi-numerical reionization models in comparison with radiative transfer simulations

NASA Astrophysics Data System (ADS)

Hutter, Anne

2018-03-01

We have developed a modular semi-numerical code that computes the time and spatially dependent ionization of neutral hydrogen (H I), neutral (He I) and singly ionized helium (He II) in the intergalactic medium (IGM). The model accounts for recombinations and provides different descriptions for the photoionization rate that are used to calculate the residual H I fraction in ionized regions. We compare different semi-numerical reionization schemes to a radiative transfer (RT) simulation. We use the RT simulation as a benchmark, and find that the semi-numerical approaches produce similar H II and He II morphologies and power spectra of the H I 21cm signal throughout reionization. As we do not track partial ionization of He II, the extent of the double ionized helium (He III) regions is consistently smaller. In contrast to previous comparison projects, the ionizing emissivity in our semi-numerical scheme is not adjusted to reproduce the redshift evolution of the RT simulation, but directly derived from the RT simulation spectra. Among schemes that identify the ionized regions by the ratio of the number of ionization and absorption events on different spatial smoothing scales, we find those that mark the entire sphere as ionized when the ionization criterion is fulfilled to result in significantly accelerated reionization compared to the RT simulation. Conversely, those that flag only the central cell as ionized yield very similar but slightly delayed redshift evolution of reionization, with up to 20% ionizing photons lost. Despite the overall agreement with the RT simulation, our results suggests that constraining ionizing emissivity sensitive parameters from semi-numerical galaxy formation-reionization models are subject to photon nonconservation.

Light cone effect on the reionization 21-cm signal - II. Evolution, anisotropies and observational implications

NASA Astrophysics Data System (ADS)

Datta, Kanan K.; Jensen, Hannes; Majumdar, Suman; Mellema, Garrelt; Iliev, Ilian T.; Mao, Yi; Shapiro, Paul R.; Ahn, Kyungjin

2014-08-01

Measurements of the H I 21-cm power spectra from the reionization epoch will be influenced by the evolution of the signal along the line-of-sight direction of any observed volume. We use numerical as well as seminumerical simulations of reionization in a cubic volume of 607 Mpc across to study this so-called light-cone effect on the H I 21-cm power spectrum. We find that the light-cone effect has the largest impact at two different stages of reionization: one when reionization is ˜20 per cent and other when it is ˜80 per cent completed. We find a factor of ˜4 amplification of the power spectrum at the largest scale available in our simulations. We do not find any significant anisotropy in the 21-cm power spectrum due to the light-cone effect. We argue that for the power spectrum to become anisotropic, the light-cone effect would have to make the ionized bubbles significantly elongated or compressed along the line of sight, which would require extreme reionization scenarios. We also calculate the two-point correlation functions parallel and perpendicular to the line of sight and find them to differ. Finally, we calculate an optimum frequency bandwidth below which the light-cone effect can be neglected when extracting power spectra from observations. We find that if one is willing to accept a 10 per cent error due to the light-cone effect, the optimum frequency bandwidth for k = 0.056 Mpc-1 is ˜7.5 MHz. For k = 0.15 and 0.41 Mpc-1, the optimum bandwidth is ˜11 and ˜16 MHz, respectively.

“An Effect That is Deeper Than Beating” Family Violence in Jordanian Women

PubMed Central

Morse, Diane S; Paldi, Yael; Egbarya, Samah Salaime; Clark, Cari Jo

2012-01-01

This study informs healthcare approaches to gender-based family violence through focus groups with Jordanian women. The authors conducted a thematic qualitative analysis of 12 focus groups among 70 married, divorced, or widowed women about their experiences and beliefs regarding family violence. Five themes relevant to healthcare providers were identified. Three of the themes addressed participant-perceived causes of gender-based family violence: 1) unmet gender role expectations, 2) stigma and social norms, and 3) extended family roles. The fourth theme reflects effects on victims. The fifth theme reflects protective qualities and help seeking behaviors. The themes identified in the analysis reveal multiple ways that gender-based family violence can contribute to health problems and that it can be kept secret by Jordanian women as patients. Potential clues are described for the violence which may not be typically explored in a medical encounter. Additional ways that Jordanian families may seek help from other family or clergy instead of police and family violence agencies are described. Implications of these results for healthcare providers who care both for Jordanians and Arab immigrants in Western cultures are discussed. PMID:22329396

Warm Dark Matter and Cosmic Reionization

DOE PAGES

Villanueva-Domingo, Pablo; Gnedin, Nickolay Y.; Mena, Olga

2018-01-10

In models with dark matter made of particles with keV masses, such as a sterile neutrino, small-scale density perturbations are suppressed, delaying the period at which the lowest mass galaxies are formed and therefore shifting the reionization processes to later epochs. In this study, focusing on Warm Dark Matter (WDM) with masses close to its present lower bound, i.e., around the 3 keV region, we derive constraints from galaxy luminosity functions, the ionization history and the Gunn–Peterson effect. We show that even if star formation efficiency in the simulations is adjusted to match the observed UV galaxy luminosity functions in bothmore » CDM and WDM models, the full distribution of Gunn–Peterson optical depth retains the strong signature of delayed reionization in the WDM model. Furthermore, until the star formation and stellar feedback model used in modern galaxy formation simulations is constrained better, any conclusions on the nature of dark matter derived from reionization observables remain model-dependent.« less

Warm Dark Matter and Cosmic Reionization

NASA Astrophysics Data System (ADS)

Villanueva-Domingo, Pablo; Gnedin, Nickolay Y.; Mena, Olga

2018-01-01

In models with dark matter made of particles with keV masses, such as a sterile neutrino, small-scale density perturbations are suppressed, delaying the period at which the lowest mass galaxies are formed and therefore shifting the reionization processes to later epochs. In this study, focusing on Warm Dark Matter (WDM) with masses close to its present lower bound, i.e., around the 3 keV region, we derive constraints from galaxy luminosity functions, the ionization history and the Gunn–Peterson effect. We show that even if star formation efficiency in the simulations is adjusted to match the observed UV galaxy luminosity functions in both CDM and WDM models, the full distribution of Gunn–Peterson optical depth retains the strong signature of delayed reionization in the WDM model. However, until the star formation and stellar feedback model used in modern galaxy formation simulations is constrained better, any conclusions on the nature of dark matter derived from reionization observables remain model-dependent.

Warm Dark Matter and Cosmic Reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villanueva-Domingo, Pablo; Gnedin, Nickolay Y.; Mena, Olga

In models with dark matter made of particles with keV masses, such as a sterile neutrino, small-scale density perturbations are suppressed, delaying the period at which the lowest mass galaxies are formed and therefore shifting the reionization processes to later epochs. In this study, focusing on Warm Dark Matter (WDM) with masses close to its present lower bound, i.e., around the 3 keV region, we derive constraints from galaxy luminosity functions, the ionization history and the Gunn–Peterson effect. We show that even if star formation efficiency in the simulations is adjusted to match the observed UV galaxy luminosity functions in bothmore » CDM and WDM models, the full distribution of Gunn–Peterson optical depth retains the strong signature of delayed reionization in the WDM model. Furthermore, until the star formation and stellar feedback model used in modern galaxy formation simulations is constrained better, any conclusions on the nature of dark matter derived from reionization observables remain model-dependent.« less

Reionization and Galaxy Formation in Warm Dark Matter Cosmologies

NASA Astrophysics Data System (ADS)

Dayal, Pratika; Choudhury, Tirthankar Roy; Bromm, Volker; Pacucci, Fabio

2017-02-01

We compare model results from a semi-analytic (merger-tree based) framework for high-redshift (z ≃ 5-20) galaxy formation against reionization indicators, including the Planck electron scattering optical depth (τ es) and the ionizing photon emissivity ({\\dot{n}}{ion}), to shed light on the reionization history and sources in Cold (CDM) and Warm Dark Matter (WDM; particle masses of {m}x = 1.5, 3, and 5 keV) cosmologies. This model includes all of the key processes of star formation, supernova feedback, the merger/accretion/ejection driven evolution of gas and stellar mass and the effect of the ultra-violet background (UVB), created during reionization, in photo-evaporating the gas content of galaxies in halos with M h ≲ 109 {M}⊙ . We find that the delay in the start of reionization in light (1.5 keV) WDM models can be compensated by a steeper redshift evolution of the ionizing photon escape fraction and a faster mass assembly, resulting in reionization ending at comparable redshifts (z ≃ 5.5) in all the dark matter models considered. We find that the bulk of the reionization photons come from galaxies with a halo mass of M h ≲ 109 {M}⊙ and a UV magnitude of -15 ≲ M UV ≲ -10 in CDM. The progressive suppression of low-mass halos with decreasing {m}x leads to a shift in the “reionization” population to larger halo masses of M h ≳ 109 {M}⊙ and -17 ≲ M UV ≲ -13 for 1.5 keV WDM. We find that current observations of τ es and the ultra violet luminosity function are equally compatible with all the (cold and warm) dark matter models considered in this work. Quantifying the impact of the UVB on galaxy observables (luminosity functions, stellar mass densities, and stellar to halo mass ratios) for different DM models, we propose that global indicators including the redshift evolution of the stellar mass density and the stellar mass-halo mass relation, observable with the James Webb Space Telescope, can be used to distinguish between CDM and WDM (1.5 keV) cosmologies.

Hydrogen Epoch of Reionization Array (HERA)

NASA Astrophysics Data System (ADS)

DeBoer, David R.; HERA

2015-01-01

The Hydrogen Epoch of Reionization Arrays (HERA - reionization.org) roadmap uses the unique properties of the neutral hydrogen (HI) 21cm line to probe our cosmic dawn: from the birth of the first stars and black holes, through the full reionization of the primordial intergalactic medium (IGM). HERA is a collaboration between the Precision Array Probing the Epoch of Reionization (PAPER - eor.berkeley.edu), the US-based Murchison Widefield Array (MWA - mwatelescope.org), and MIT Epoch of Reionization (MITEOR) teams along with the South African SKA-SA, University of KwaZulu Natal and the University of Cambridge Cavendish Laborabory. HERA has recently been awarded a National Science Foundation Mid-Scale Innovation Program grant to begin the next phase.HERA leverages the operation of the PAPER and MWA telescopes to explore techniques and designs required to detect the primordial HI signal in the presence of systematics and radio continuum foreground emission some four orders of magnitude brighter. With this understanding, we are now able to remove foregrounds to the limits of our sensitivity, culminating in the first physically meaningful upper limits. A redundant calibration algorithm from MITEOR improves the sensitivity of the approach.Building on this, the next stage of HERA incorporates a 14m diameter antenna element that is optimized both for sensitivity and for minimizing foreground systematics. Arranging these elements in a compact hexagonal grid yields an array that facilitates calibration, leverages proven foreground removal techniques, and is scalable to large collecting areas. HERA will be located in the radio quiet environment of the SKA site in the Karoo region of South Africa (where PAPER is currently located). It will have a sensitivity close to two orders of magnitude better than PAPER and the MWA to ensure a robust detection. With its sensitivity and broader frequency coverage, HERA can paint an uninterrupted picture through reionization, back to the end of the Dark Ages.This paper will present a summary of the current understanding of the signal characteristics and measurements and describe the funded and planned HERA telescope to be built to detect and characterize the EoR power spectrum.

The health-seeking behaviours of first-time mothers with persistent pelvic girdle pain after childbirth in Ireland: A descriptive qualitative study.

PubMed

Wuytack, Francesca; Curtis, Elizabeth; Begley, Cecily

2015-11-01

to explore the health-seeking behaviours of primiparous women with pelvic girdle pain persisting for more than three months post partum. a descriptive qualitative design involving face-to-face semi-structured interviews following institutional ethical approval. Transcripts were analysed using thematic analysis. an urban hospital in Ireland. a purposive sample of 23 consenting first-time mothers with pelvic girdle pain persisting for at least three months post partum. 'they didn't ask, I didn't tell' was a key theme, which included emerging categories of a perceived lack of follow-up post partum, and feeling ignored by healthcare professionals. The theme 'Seeking advice and support' describes women's role of talking to others, and triggers and barriers to getting help. 'Coping strategies' was the third theme emerging from the interviews, whereby participants described different strategies they used to deal with their symptoms, although many expressed uncertainty about what to do or who to see. our findings show the importance of appropriate information and follow-up care for women with pelvic girdle pain and highlight barriers they encounter in seeking help. They also question the duration of postnatal care as participants felt that postnatal care was stopped too early. The findings may assist maternity care providers in addressing mothers' expectations and needs related to persistent pelvic girdle pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Results From PAPER/HERA

NASA Astrophysics Data System (ADS)

Pober, Jonathan C.

2018-05-01

The Precision Array for Probing the Epoch of Reionization (PAPER) was a first-generation 21 cm cosmology experiment with the specific goal of detecting the power spectrum of the 21 cm emission from the Epoch of Reionization. Analysis of PAPER data is still ongoing, but lessons learned from PAPER to date have played a critical role in designing the next-generation Hydrogen Epoch of Reionization Array (HERA) experiment. This article reviews five key design choices made by PAPER: use of a non-imaging configuration, redundancy, short baselines, small antenna elements, and a large instantaneous bandwidth. We describe the impact of these choices and the role they played in designing HERA.

Emulating Simulations of Cosmic Dawn for 21 cm Power Spectrum Constraints on Cosmology, Reionization, and X-Ray Heating

NASA Astrophysics Data System (ADS)

Kern, Nicholas S.; Liu, Adrian; Parsons, Aaron R.; Mesinger, Andrei; Greig, Bradley

2017-10-01

Current and upcoming radio interferometric experiments are aiming to make a statistical characterization of the high-redshift 21 cm fluctuation signal spanning the hydrogen reionization and X-ray heating epochs of the universe. However, connecting 21 cm statistics to the underlying physical parameters is complicated by the theoretical challenge of modeling the relevant physics at computational speeds quick enough to enable exploration of the high-dimensional and weakly constrained parameter space. In this work, we use machine learning algorithms to build a fast emulator that can accurately mimic an expensive simulation of the 21 cm signal across a wide parameter space. We embed our emulator within a Markov Chain Monte Carlo framework in order to perform Bayesian parameter constraints over a large number of model parameters, including those that govern the Epoch of Reionization, the Epoch of X-ray Heating, and cosmology. As a worked example, we use our emulator to present an updated parameter constraint forecast for the Hydrogen Epoch of Reionization Array experiment, showing that its characterization of a fiducial 21 cm power spectrum will considerably narrow the allowed parameter space of reionization and heating parameters, and could help strengthen Planck's constraints on {σ }8. We provide both our generalized emulator code and its implementation specifically for 21 cm parameter constraints as publicly available software.

The Growth of Early Galaxies and Reionization of Hydrogen

NASA Astrophysics Data System (ADS)

Chary, Ranga Ram

2012-07-01

The reionization of the intergalactic medium about a billion years after the Big Bang was an important event which occurred due to the release of ionizing photons from the growth of stellar mass and black holes in the early Universe. By leveraging the benefits of field galaxy surveys, I will present some recent breakthroughs in our understanding of how the earliest galaxies in the Universe evolved. I will present evidence that unlike in the local Universe where galaxy growth occurs through intermittent cannibalism, star-formation in the distant Universe is a more continuous if violent process with an overabundance of massive stars. Implications for the reionization history of the Universe will also be discussed.

Detecting Patchy Reionization in the Cosmic Microwave Background.

PubMed

Smith, Kendrick M; Ferraro, Simone

2017-07-14

Upcoming cosmic microwave background (CMB) experiments will measure temperature fluctuations on small angular scales with unprecedented precision. Small-scale CMB fluctuations are a mixture of late-time effects: gravitational lensing, Doppler shifting of CMB photons by moving electrons [the kinematic Sunyaev-Zel'dovich (KSZ) effect], and residual foregrounds. We propose a new statistic which separates the KSZ signal from the others, and also allows the KSZ signal to be decomposed in redshift bins. The decomposition extends to high redshift and does not require external data sets such as galaxy surveys. In particular, the high-redshift signal from patchy reionization can be cleanly isolated, enabling future CMB experiments to make high-significance and qualitatively new measurements of the reionization era.

Winds of change: reionization by starburst galaxies

NASA Astrophysics Data System (ADS)

Sharma, Mahavir; Theuns, Tom; Frenk, Carlos; Bower, Richard G.; Crain, Robert A.; Schaller, Matthieu; Schaye, Joop

2017-06-01

We investigate the properties of the galaxies that reionized the Universe and the history of cosmic reionization using the 'Evolution and Assembly of Galaxies and their Environments' (eagle) cosmological hydrodynamical simulations. We obtain the evolution of the escape fraction of ionizing photons in galaxies assuming that galactic winds create channels through which 20 per cent of photons escape when the local surface density of star formation is greater than 0.1 M⊙ yr-1 kpc-2. Such threshold behaviour for the generation of winds is observed, and the rare local objects that have such high star formation surface densities exhibit high escape fractions of ˜10 per cent. In our model, the luminosity-weighted mean escape fraction increases with redshift as \\bar{f}_esc=0.045 ((1+z)/4)^{1.1} at z > 3, and the galaxy number weighted mean as = 2.2 × 10-3 ((1 + z)/4)4, and becomes constant ≈0.2 at redshift z > 10. The escape fraction evolves as an increasingly large fraction of stars forms above the critical surface density of star formation at earlier times. This evolution of the escape fraction, combined with that of the star formation rate density from eagle, reproduces the inferred evolution of the filling factor of ionized regions during the reionization epoch (6 < z < 8), the evolution of the post-reionization (0 ≤ z < 6) hydrogen photoionization rate and the optical depth due to Thomson scattering of the cosmic microwave background photons measured by the Planck satellite.

Probing features in inflaton potential and reionization history with future CMB space observations

NASA Astrophysics Data System (ADS)

Hazra, Dhiraj Kumar; Paoletti, Daniela; Ballardini, Mario; Finelli, Fabio; Shafieloo, Arman; Smoot, George F.; Starobinsky, Alexei A.

2018-02-01

We consider the prospects of probing features in the primordial power spectrum with future Cosmic Microwave Background (CMB) polarization measurements. In the scope of the inflationary scenario, such features in the spectrum can be produced by local non-smooth pieces in an inflaton potential (smooth and quasi-flat in general) which in turn may originate from fast phase transitions during inflation in other quantum fields interacting with the inflaton. They can fit some outliers in the CMB temperature power spectrum which are unaddressed within the standard inflationary ΛCDM model. We consider Wiggly Whipped Inflation (WWI) as a theoretical framework leading to improvements in the fit to the Planck 2015 temperature and polarization data in comparison with the standard inflationary models, although not at a statistically significant level. We show that some type of features in the potential within the WWI models, leading to oscillations in the primordial power spectrum that extend to intermediate and small scales can be constrained with high confidence (at 3σ or higher confidence level) by an instrument as the Cosmic ORigins Explorer (CORE). In order to investigate the possible confusion between inflationary features and footprints from the reionization era, we consider an extended reionization history with monotonic increase of free electrons with decrease in redshift. We discuss the present constraints on this model of extended reionization and future predictions with CORE. We also project, to what extent, this extended reionization can create confusion in identifying inflationary features in the data.

Introducing CoDa (Cosmic Dawn): Radiation-Hydrodynamics of Galaxy Formation in the Early Universe

NASA Astrophysics Data System (ADS)

Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul; Aubert, Dominique; Iliev, Ilian; Romain, Teyssier; Yepes, Gustavo; Choi, Jun-hwan; Sullivan, David; Knebe, Alexander; Gottloeber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda

2015-08-01

CoDa (Cosmic Dawn) is the largest fully coupled radiation hydrodynamics simulation of the reionization of the local Universe to date. It was performed using RAMSES-CUDATON running on 8192 nodes (i.e. 8192 GPUs) on the titan supercomputer at Oak Ridge National Laboratory to simulate a 64 h-1Mpc side box down to z=4.23. In this simulation, reionization proceeds self-consistently, driven by stellar radiation. We compare the simulation's reionization history, ionizing flux density, the cosmic star formation history and the CMB Thompson scattering optical depth with their observational values. Luminosity functions are also in rather good agreement with high redshift observations, although very bright objects (MAB1600 < -21) are overabundant in CoDa. We investigate the evolution of the intergalactic medium, and find that gas filaments present a sheathed structure, with a hot envelope surrounding a cooler core. They are however not able to self-shield, while regions denser than 10^-4.5 H atoms per comoving h^-3cm^3 are. Haloes below M ˜ 3.10^9 M⊙ are severely affected by the expanding, rising UV background: their ISM is quickly photo-heated to temperatures above our star formation threshold and therefore stop forming stars after local reionization has occured. Overall, the haloes between 10^(10-11) M⊙ dominate the star formation budget of the box for most of the Epoch of Reionization. Several additional studies will follow, looking for instance at environmental effects on galaxy properties, and the regimes of accretion.

HERA: Illuminating Our Early Universe

NASA Astrophysics Data System (ADS)

DeBoer, David

2014-06-01

The Hydrogen Epoch of Reionization Arrays (HERA) roadmap is a staged plan for using the unique properties of the 21cm line from neutral hydrogen to probe our cosmic dawn, from the birth of the first stars and black holes, through the full reionization of the primordial intergalactic medium (IGM). HERA is a collaboration between the Precision Array Probing the Epoch of Reionization (PAPER), US-Murchison Widefield Array (MWA), and MIT Epoch of Reionization (MITEOR) teams.The first phase of the HERA roadmap entailed the operation of the PAPER and MWA telescopes to explore techniques and designs required to detect the primordial HI signal in the presence of radio continuum foreground emission some four orders of magnitude brighter. Studies with PAPER and the MWA have led to a new understanding of the interplay of foreground and instrumental systematics in the context of a three-dimensional cosmological intensity-mapping experiment. We are now able to remove foregrounds to the limits of our sensitivity with these instruments, culminating in the first physically meaningful upper limits on the power spectrum of 2 cm emission from reionization.Building on this understanding, the next stage of HERA entails a new 14m diameter antenna element that is optimized both for sensitivity and for minimizing foreground systematics. Arranging these elements in a compact hexagonal grid yields an array that facilitates calibration, leverages proven foreground removal techniques, and is scalable to large collecting areas. The HERA phase II will be located in the radio quiet environment of the SKA site in Karoo, South Africa, and have a sensitivity close to two orders of magnitude better than PAPER and the MWA, with broader frequency coverage, HERA can paint an uninterrupted picture through reionization, back to the end of the Dark Ages.This paper will present a summary of the current understanding of the signal characteristics and measurements and describe this planned HERA telescope to be built to detect and characterize the EoR power spectrum.

False Fire Alarms: A Deviant Pattern of Seeking Help.

ERIC Educational Resources Information Center

Camblin, Louise; Weinland, Laura

1987-01-01

Discusses the phenomenon of false fire alarms, the deliberate, intentional false reporting of fires, by mentally troubled persons as a primitive kind of help-seeking behavior. Several common themes found by reviewing false alarm cases are presented. Suggests that identifying the intrapsychic dynamics of false alarm reporters could be useful in…

Local reionization histories with a merger tree of the HII regions

NASA Astrophysics Data System (ADS)

Chardin, Jonathan; Aubert, Dominique; Ocvirk, Pierre

2014-08-01

Aims: We investigate simple properties of the initial stage of the reionization process around progenitors of galaxies, such as the extent of the initial HII region before its fusion with the UV background, and the duration of its propagation. Methods: We used a set of four reionization simulations with different resolutions and ionizing source prescriptions. By using a merger tree of the HII regions we compiled a catalog of the HII region properties. When the ionized regions undergo a major-merger event, we considered that they belong to the global UV background. From the lifetime of the region and from their volume until this moment we drew typical local reionization histories as a function of time and investigated the relation between these histories and the halo mass progenitors of the regions. We then used an average mass accretion history model (AMAH) to extrapolate the halo mass inside the region from high z to z = 0 to predict the past reionization histories of galaxies we see today. Results: We found that the later an HII region appears during the reionization period, the shorter their related lifetime is and the smaller their volume before they merge with the global UV background. Quantitatively, the duration and extent of the initial growth of an HII region is strongly dependent on the mass of the inner halo and can be as long as ~50% of the reionization epoch. We found that the more massive a halo is today, the earlier it appears and the larger is the extension and the longer the propagation duration of its HII region. Quantitative predictions differ depending on the box size or the source model: small simulated volumes are affected by proximity effects between HII regions, and halo-based source models predict smaller regions and slower I-front expansion than models that use star particles as ionizing sources. Applying this extrapolation to Milky Way-type halos leads to a maximal extent of 1.1 Mpc/h for the initial HII region that established itself in ~150-200 ± 20 Myr. This is consistent with the prediction made using constrained Local Group simulations. For halos with masses similar to those of the Local Group (MW + M31), our result suggests that statistically it has not been influenced by an external front coming from a Virgo-like cluster.

“I Was Just Trying To Stick It Out Until I Realized That I Couldn't”: A Phenomenological Investigation of Support Seeking Among Older Adults With Complicated Grief*

PubMed Central

Ghesquiere, Angela

2014-01-01

Complicated Grief (CG) is a prolonged, impairing mental health condition affecting about 7% of the bereaved. CG may be especially prevalent in older adults. Though evidence-based treatments for CG have been developed, little is known about support-seeking in older adults with CG. This study used the descriptive phenomenological approach to explore the CG support-seeking process. In-depth interviews were conducted with 8 CG-positive older adults who had completed participation in a randomized clinical trial of CG treatment. Five primary themes arose: observing that grief was causing a great deal of distress and impairment; grief not meeting expectations of what grief “should be”; an important influence of social relationships on support-seeking; lack of effectiveness of grief support groups and/or care from mental health professionals prior to study enrollment; and strong reactions to the label of CG. Themes may hep inform efforts to engage older adults with CG in effective care. PMID:24547662

Health-seeking experience of North Korean women defectors in South Korea.

PubMed

Chung, Chong-Hee; Kang, Hee-Young; Lake, Pamela K

2018-05-01

The objective of the study was to explore and describe the health-seeking experience of North Korean women defectors settled in South Korea. A qualitative study was conducted using Colaizzi's phenomenological method. Participants were 10 North Korean women defectors. Data were collected through in-depth, unstructured interviews with individual participants. A total of 24 themes, eight theme clusters, and four categories emerged. The structure of the health-seeking experience for them was identified as 'having new opportunities to better understand my own body and protecting my own health while adapting to the health care system of the South'. The four categories were: finding out about my own body, confusion regarding the medical treatment, enjoying the health care benefits, and protecting my own health. The findings of this study will help improve the understanding of the health-seeking experience of North Korean women defectors and provide valuable resources to assist in caring for their health needs. This will contribute to preparing the groundwork to enhance the quality of their remaining life in South Korea. © 2018 Wiley Periodicals, Inc.

Themes in the Research on Preservice Teachers' Views of Cultural Diversity: Implications for Researching Millennial Preservice Teachers

ERIC Educational Resources Information Center

Castro, Antonio J.

2010-01-01

This article traces themes found in the research on preservice teachers' views of cultural diversity published in peer-reviewed journals from 1985 to 2007. The article seeks to draw insights that inform education researchers interested in interrogating and unpacking views about diversity expressed by today's millennial college students. Findings…

Reionization of the Universe Induced by Primordial Black Holes

NASA Astrophysics Data System (ADS)

Gibilisco, Marina

The history of the universe after the recombination probably involves a reionization epoch, as the Gunn-Peterson test seems to suggest: if this is the case, the consequences of such a phenomenon should be relevant, both for the induced enhancement of the cosmic microwave background (CMB) polarization and for the possible damping of the CMB fluctuations on small angular scales (θ~1º). In this paper, I will study a model of reionization at redshifts z≤60 caused by the evaporation of primordial black holes; photon emission only from nonrotating black holes is considered. A system of coupled differential equations, giving the time evolution of the ionization degree x, of the plasma temperature Te and of the photon number density nγ, is solved in an analytical way: the results obtained show that such a kind of reionization is possible, being able to increase the ionization degree of the universe from a value x=0.002 (just after the recombination) to values near 1 (when the black holes evaporation ends). In particular, taking the evaporation redshift equal to the reionization redshift zR, one obtains total reionization (i.e. x=1) for 15≤zR≤30, while only a partial effect (x~0.75÷0.90) is present for higher values of zR (40≤zR≤60). The fast increase of x seems to agree with the predictions of an exponential reionization model discussed in a previous study of the CMB polarization induced by gravitational waves. The evolution of the plasma temperature Te is also estimated: it is affected in a less important way by the primordial black holes evaporation process, as we expect from the experimental FIRAS upper limit on the comptonization parameter yc (yc<2.5×10-5). The photoionization process here studied seems generally able to maintain the plasma in a ionized state without heating it up at very high temperatures; however, an improvement in the numerical calculation of Te is necessary in order to take into account in a more satisfactory way the collisional and excitation cooling, that can limit the increase of the plasma temperature. In this model, the density of primordial black holes (PBH’s) necessary to give a nonnegligible reionization is an important parameter: here I will consider various birth times tin and various initial density for the PBH’s, showing that the most effective reionization is obtained for zR≤30 and for PBH’s formed at tin~10-28 secafter the big bang. An estimate of their present density for this formation time gives a value ρ0=2.44×10-38g cm-3, corresponding to a present density parameter ΩPBH equal to 5.20×10-9. This result agrees with the experimental upper limit ΩPBH≤(7.6±2.6)×10-9 h(-1.95±0.15) A future improvement of this work will consider also massive particle emission from both rotating and nonrotating black holes and a spectrum taking also into account quarks and gluons jets emission.

Health-seeking behaviour for schistosomiasis: a systematic review of qualitative and quantitative literature.

PubMed

Cronin, Thomas; Sheppard, James; de Wildt, Gilles

2013-01-01

Schistosomiasis is a chronic and debilitating parasitic disease acquired through contact with infested freshwater. An essential component of its control is passive case finding, which, in order to be effective, requires a detailed understanding of health-seeking behaviour. This study aimed to systematically review evidence on health-seeking behaviour for schistosomiasis, in order to determine factors influencing use or non-use of modern health services for the infection. Quantitative, qualitative and mixed method studies reporting on factors related to seeking treatment from modern health services for schistosomiasis were obtained, combining electronic and hand searching. Data extraction and quality assessment of the included articles were performed, with all studies qualitatively analysed using thematic synthesis. A total of 19 studies were included in the review. Six themes were identified from the analysis: biomedical knowledge on schistosomiasis, perceptions of modern treatment and health services, financial considerations of treatment, perceptions on the symptoms, stigma of the infection, and physical location and community. These findings were consistent across studies of different design, setting and quality. Many of the themes identified echo existing literature on health-seeking behaviour. The synthesis also highlighted the role of stigma, and aspects of the physical location and community that may affect treatment-seeking for schistosomiasis. Health education programmes that intend to improve the utilisation of modern health services for the infection need to acknowledge the multiple determinants influencing their use. Future research should move beyond describing health-seeking behaviour to identifying the factors that underlay such behaviour.

Young Men, Help-Seeking, and Mental Health Services: Exploring Barriers and Solutions.

PubMed

Lynch, Louise; Long, Maggie; Moorhead, Anne

2018-01-01

International research has identified young men as reluctant to seek help for mental health problems. This research explored barriers and solutions to professional help seeking for mental health problems among young men living in the North West of Ireland. A qualitative approach, using two focus groups with six participants each and five face-to-face interviews, was conducted with men aged 18 to 24 years (total N = 17). Data were analyzed using thematic analysis. Seven key themes of barriers to professional help seeking were identified: "acceptance from peers," "personal challenges," "cultural and environmental influences," "self-medicating with alcohol," "perspectives around seeking professional help," "fear of homophobic responses," and "traditional masculine ideals." Five key themes of solutions to these barriers included "tailored mental health advertising," "integrating mental health into formal education," "education through semiformal support services," "accessible mental health care," and "making new meaning." Interesting findings on barriers include fear of psychiatric medication, fear of homophobic responses from professionals, the legacy of Catholic attitudes, and the genuine need for care. This study offers an in-depth exploration of how young men experience barriers and uniquely offers solutions identified by participants themselves. Youth work settings were identified as a resource for engaging young men in mental health work. Young men can be encouraged to seek help if services and professionals actively address barriers, combining advertising, services, and education, with particular attention and respect to how and when young men seek help and with whom they want to share their problems.

Barriers to seeking care for accidental bowel leakage: a qualitative study

PubMed Central

Rogers, Rebecca G.; Wise, Meg E.

2016-01-01

Introduction and hypothesis Fewer than 50 % of women with urinary incontinence (UI) and 30 % of women with accidental bowel leakage (ABL) seek care. We sought to describe barriers to care seeking for ABL to inform development of an instrument to measure these barriers. Methods We recruited women with ABL with varied prior care-seeking experiences to participate in focus groups and cognitive interviews so we could understand factors that may have prevented or delayed care seeking. Focus groups continued until thematic saturation was reached using conventional content analysis. Final themes were established and characterized by comparing within and across the focus groups and with previously described UI and ABL care-seeking barriers. Cognitive interviews were confirmatory. Results Thirty-nine women (aged 46–85) participated in six focus groups and ten cognitive interviews; 89 % were white, 8 % African American, and 3 % Latina. We identified 12 barriers to seeking care for ABL: (1) Lack of knowledge about the condition; (2) Lack of knowledge about treatment; (3) Fear of testing/treatment; (4) Normative thinking; (5) Avoidance/ denial; (6) Life impact; (7) Embarrassment/shame; (8) Self-blame; (9) Stigma; (10) Isolation; (11) Provider barriers; (12) Access limitations. These 12 barriers encompassed three overarching themes: the internalized self in relation to ABL; perceptions about ABL and its treatments; and interaction with the healthcare system. Conclusions ABL care-seeking barriers are similar to those described for UI, with the notable addition of lack of knowledge that ABL is a medical condition experienced by others. Interventions to promote access to effective treatments for ABL should include information about prevalence and treatability. PMID:27844123

Barriers to seeking care for accidental bowel leakage: a qualitative study.

PubMed

Brown, Heidi Wendell; Rogers, Rebecca G; Wise, Meg E

2017-04-01

Fewer than 50 % of women with urinary incontinence (UI) and 30 % of women with accidental bowel leakage (ABL) seek care. We sought to describe barriers to care seeking for ABL to inform development of an instrument to measure these barriers. We recruited women with ABL with varied prior care-seeking experiences to participate in focus groups and cognitive interviews so we could understand factors that may have prevented or delayed care seeking. Focus groups continued until thematic saturation was reached using conventional content analysis. Final themes were established and characterized by comparing within and across the focus groups and with previously described UI and ABL care-seeking barriers. Cognitive interviews were confirmatory. Thirty-nine women (aged 46-85) participated in six focus groups and ten cognitive interviews; 89 % were white, 8 % African American, and 3 % Latina. We identified 12 barriers to seeking care for ABL: (1) Lack of knowledge about the condition; (2) Lack of knowledge about treatment; (3) Fear of testing/treatment; (4) Normative thinking; (5) Avoidance/denial; (6) Life impact; (7) Embarrassment/shame; (8) Self-blame; (9) Stigma; (10) Isolation; (11) Provider barriers; (12) Access limitations. These 12 barriers encompassed three overarching themes: the internalized self in relation to ABL; perceptions about ABL and its treatments; and interaction with the healthcare system. ABL care-seeking barriers are similar to those described for UI, with the notable addition of lack of knowledge that ABL is a medical condition experienced by others. Interventions to promote access to effective treatments for ABL should include information about prevalence and treatability.

Unravelling the Lifelong Learning Process for Canadian Workers and Adult Learners Acquiring Higher Skills

ERIC Educational Resources Information Center

Taylor, Maurice; Trumpower, David; Pavic, Ivana

2013-01-01

This article reports on a mixed methods study that investigated aspects of formal, non-formal and informal learning for workers and adult high school learners seeking literacy and essential skills. Three key themes emerged from the qualitative data: motivations for participation in various forms of learning; seeking out informal learning…

"Voices of fear and safety" women's ambivalence towards breast cancer and breast health: a qualitative study from Jordan.

PubMed

Taha, Hana; Al-Qutob, Raeda; Nyström, Lennarth; Wahlström, Rolf; Berggren, Vanja

2012-07-26

Breast cancer is the leading cause of cancer mortality among Jordanian women. Breast malignancies are detected at late stages as a result of deferred breast health-seeking behaviour. The aim of this study was to explore Jordanian women's views and perceptions about breast cancer and breast health. We performed an explorative qualitative study with purposive sampling. Ten focus groups were conducted consisting of 64 women (aged 20 to 65 years) with no previous history and no symptoms of breast cancer from four governorates in Jordan. The transcribed data was analysed using latent content analysis. Three themes were constructed from the group discussions: a) Ambivalence in prioritizing own health; b) Feeling fear of breast cancer; and c) Feeling safe from breast cancer. The first theme was seen in women's prioritizing children and family needs and in their experiencing family and social support towards seeking breast health care. The second theme was building on women's perception of breast cancer as an incurable disease associated with suffering and death, their fear of the risk of diminished femininity, husband's rejection and social stigmatization, adding to their apprehensions about breast health examinations. The third theme emerged from the women's perceiving themselves as not being in the risk zone for breast cancer and in their accepting breast cancer as a test from God. In contrast, women also experienced comfort in acquiring breast health knowledge that soothed their fears and motivated them to seek early detection examinations. Women's ambivalence in prioritizing their own health and feelings of fear and safety could be better addressed by designing breast health interventions that emphasize the good prognosis for breast cancer when detected early, involve breast cancer survivors in breast health awareness campaigns and catalyse family support to encourage women to seek breast health care.

“Voices of Fear and Safety” Women’s ambivalence towards breast cancer and breast health: a qualitative study from Jordan

PubMed Central

2012-01-01

Background Breast cancer is the leading cause of cancer mortality among Jordanian women. Breast malignancies are detected at late stages as a result of deferred breast health-seeking behaviour. The aim of this study was to explore Jordanian women’s views and perceptions about breast cancer and breast health. Methods We performed an explorative qualitative study with purposive sampling. Ten focus groups were conducted consisting of 64 women (aged 20 to 65 years) with no previous history and no symptoms of breast cancer from four governorates in Jordan. The transcribed data was analysed using latent content analysis. Results Three themes were constructed from the group discussions: a) Ambivalence in prioritizing own health; b) Feeling fear of breast cancer; and c) Feeling safe from breast cancer. The first theme was seen in women’s prioritizing children and family needs and in their experiencing family and social support towards seeking breast health care. The second theme was building on women’s perception of breast cancer as an incurable disease associated with suffering and death, their fear of the risk of diminished femininity, husband’s rejection and social stigmatization, adding to their apprehensions about breast health examinations. The third theme emerged from the women’s perceiving themselves as not being in the risk zone for breast cancer and in their accepting breast cancer as a test from God. In contrast, women also experienced comfort in acquiring breast health knowledge that soothed their fears and motivated them to seek early detection examinations. Conclusions Women’s ambivalence in prioritizing their own health and feelings of fear and safety could be better addressed by designing breast health interventions that emphasize the good prognosis for breast cancer when detected early, involve breast cancer survivors in breast health awareness campaigns and catalyse family support to encourage women to seek breast health care. PMID:22834874

Friend or foe? An exploratory study of Australian parents' use of asynchronous discussion boards in childhood obesity.

PubMed

Appleton, Jessica; Fowler, Cathrine; Brown, Nicola

2014-01-01

The use of Internet and social media is increasing in every area of life. Parents are increasingly using online mediums to seek information about their children's health. Therefore, this is becoming an increasingly important topic area for health professionals to acknowledge. Developing an understanding about the dissemination of child health information through these online mediums will assist health professional to continue to engage and support parents to seek and share accurate and safe child health information. To explore parents' use of asynchronous online discussion boards for child health information seeking, advice and social support. A qualitative descriptive approach using an a priori template analysis was used to explore 34 discussions threads sampled from two Australian based online parenting discussion forums. To contain the scope of this study the threads chosen focused on childhood obesity in the Australian context. Four major themes related to parents' use of asynchronous online discussion boards were found. These were seeking advice, sharing advice, social support and making judgement. This final theme of making judgements included parents' perceptions of health professionals' advice. Asynchronous online discussion boards are online mediums being utilised for seeking and sharing child health related information and support between parents. The notion

The Aurora radiation-hydrodynamical simulations of reionization: calibration and first results

NASA Astrophysics Data System (ADS)

Pawlik, Andreas H.; Rahmati, Alireza; Schaye, Joop; Jeon, Myoungwon; Dalla Vecchia, Claudio

2017-04-01

We introduce a new suite of radiation-hydrodynamical simulations of galaxy formation and reionization called Aurora. The Aurora simulations make use of a spatially adaptive radiative transfer technique that lets us accurately capture the small-scale structure in the gas at the resolution of the hydrodynamics, in cosmological volumes. In addition to ionizing radiation, Aurora includes galactic winds driven by star formation and the enrichment of the universe with metals synthesized in the stars. Our reference simulation uses 2 × 5123 dark matter and gas particles in a box of size 25 h-1 comoving Mpc with a force softening scale of at most 0.28 h-1 kpc. It is accompanied by simulations in larger and smaller boxes and at higher and lower resolution, employing up to 2 × 10243 particles, to investigate numerical convergence. All simulations are calibrated to yield simulated star formation rate functions in close agreement with observational constraints at redshift z = 7 and to achieve reionization at z ≈ 8.3, which is consistent with the observed optical depth to reionization. We focus on the design and calibration of the simulations and present some first results. The median stellar metallicities of low-mass galaxies at z = 6 are consistent with the metallicities of dwarf galaxies in the Local Group, which are believed to have formed most of their stars at high redshifts. After reionization, the mean photoionization rate decreases systematically with increasing resolution. This coincides with a systematic increase in the abundance of neutral hydrogen absorbers in the intergalactic medium.

A tale of seven narrow spikes and a long trough: constraining the timing of the percolation of H II bubbles at the tail end of reionization with ULAS J1120+0641

NASA Astrophysics Data System (ADS)

Chardin, Jonathan; Haehnelt, Martin G.; Bosman, Sarah E. I.; Puchwein, Ewald

2018-01-01

High signal-to-noise observations of the Ly α forest transmissivity in the z = 7.085 quasi-stellar object (QSO) ULAS J1120+0641 show seven narrow transmission spikes followed by a long 240 cMpc h-1 trough. Here, we use radiative transfer simulations of cosmic reionization previously calibrated to match a wider range of Ly α forest data to show that the occurrence of seven transmission spikes in the narrow redshift range z = 5.85-6.1 is very sensitive to the exact timing of reionization. Occurrence of the spikes requires the most underdense regions of the intergalactic medium to be already fully ionized. The rapid onset of a long trough at z = 6.12 requires a strong decrease of the photoionization rate Γ at z ≳ 6.1 in this line of sight, consistent with the end of percolation at this redshift. The narrow range of reionization histories that we previously found to be consistent with a wider range of Ly α forest data have a reasonable probability of showing seven spikes and the mock absorption spectra provide an excellent match to the spikes and the trough in the observed spectrum of ULAS J1120+0641. Larger samples of high signal-to-noise searches for rare Ly α transmission spikes at z > 5.8 should therefore provide important further insights into the exact timing of the percolation of H II bubbles at the tail end of reionization.

Bubble size statistics during reionization from 21-cm tomography

NASA Astrophysics Data System (ADS)

Giri, Sambit K.; Mellema, Garrelt; Dixon, Keri L.; Iliev, Ilian T.

2018-01-01

The upcoming SKA1-Low radio interferometer will be sensitive enough to produce tomographic imaging data of the redshifted 21-cm signal from the Epoch of Reionization. Due to the non-Gaussian distribution of the signal, a power spectrum analysis alone will not provide a complete description of its properties. Here, we consider an additional metric which could be derived from tomographic imaging data, namely the bubble size distribution of ionized regions. We study three methods that have previously been used to characterize bubble size distributions in simulation data for the hydrogen ionization fraction - the spherical-average (SPA), mean-free-path (MFP) and friends-of-friends (FOF) methods - and apply them to simulated 21-cm data cubes. Our simulated data cubes have the (sensitivity-dictated) resolution expected for the SKA1-Low reionization experiment and we study the impact of both the light-cone (LC) and redshift space distortion (RSD) effects. To identify ionized regions in the 21-cm data we introduce a new, self-adjusting thresholding approach based on the K-Means algorithm. We find that the fraction of ionized cells identified in this way consistently falls below the mean volume-averaged ionized fraction. From a comparison of the three bubble size methods, we conclude that all three methods are useful, but that the MFP method performs best in terms of tracking the progress of reionization and separating different reionization scenarios. The LC effect is found to affect data spanning more than about 10 MHz in frequency (Δz ∼ 0.5). We find that RSDs only marginally affect the bubble size distributions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, Aaron R.; Liu, Adrian; Ali, Zaki S.

We present new constraints on the 21 cm Epoch of Reionization (EoR) power spectrum derived from three months of observing with a 32 antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization in South Africa. In this paper, we demonstrate the efficacy of the delay-spectrum approach to avoiding foregrounds, achieving over eight orders of magnitude of foreground suppression (in mK{sup 2}). Combining this approach with a procedure for removing off-diagonal covariances arising from instrumental systematics, we achieve a best 2σ upper limit of (41 mK){sup 2} for k = 0.27 h Mpc{sup –1}more » at z = 7.7. This limit falls within an order of magnitude of the brighter predictions of the expected 21 cm EoR signal level. Using the upper limits set by these measurements, we generate new constraints on the brightness temperature of 21 cm emission in neutral regions for various reionization models. We show that for several ionization scenarios, our measurements are inconsistent with cold reionization. That is, heating of the neutral intergalactic medium (IGM) is necessary to remain consistent with the constraints we report. Hence, we have suggestive evidence that by z = 7.7, the H I has been warmed from its cold primordial state, probably by X-rays from high-mass X-ray binaries or miniquasars. The strength of this evidence depends on the ionization state of the IGM, which we are not yet able to constrain. This result is consistent with standard predictions for how reionization might have proceeded.« less

Prediction of the 21-cm signal from reionization: comparison between 3D and 1D radiative transfer schemes

NASA Astrophysics Data System (ADS)

Ghara, Raghunath; Mellema, Garrelt; Giri, Sambit K.; Choudhury, T. Roy; Datta, Kanan K.; Majumdar, Suman

2018-05-01

Three-dimensional radiative transfer simulations of the epoch of reionization can produce realistic results, but are computationally expensive. On the other hand, simulations relying on one-dimensional radiative transfer solutions are faster but limited in accuracy due to their more approximate nature. Here, we compare the performance of the reionization simulation codes GRIZZLY and C2-RAY which use 1D and 3D radiative transfer schemes, respectively. The comparison is performed using the same cosmological density fields, halo catalogues, and source properties. We find that the ionization maps, as well as the 21-cm signal maps from these two simulations are very similar even for complex scenarios which include thermal feedback on low-mass haloes. The comparison between the schemes in terms of the statistical quantities such as the power spectrum of the brightness temperature fluctuation agrees with each other within 10 per cent error throughout the entire reionization history. GRIZZLY seems to perform slightly better than the seminumerical approaches considered in Majumdar et al. which are based on the excursion set principle. We argue that GRIZZLY can be efficiently used for exploring parameter space, establishing observations strategies, and estimating parameters from 21-cm observations.

Measuring the reionization 21 cm fluctuations using clustering wedges

NASA Astrophysics Data System (ADS)

Raut, Dinesh; Choudhury, Tirthankar Roy; Ghara, Raghunath

2018-03-01

One of the main challenges in probing the reionization epoch using the redshifted 21 cm line is that the magnitude of the signal is several orders smaller than the astrophysical foregrounds. One of the methods to deal with the problem is to avoid a wedge-shaped region in the Fourier k⊥ - k∥ space which contains the signal from the spectrally smooth foregrounds. However, measuring the spherically averaged power spectrum using only modes outside this wedge (i.e. in the reionization window) leads to a bias. We provide a prescription, based on expanding the power spectrum in terms of the shifted Legendre polynomials, which can be used to compute the angular moments of the power spectrum in the reionization window. The prescription requires computation of the monopole, quadrupole, and hexadecapole moments of the power spectrum using the theoretical model under consideration and also the knowledge of the effective extent of the foreground wedge in the k⊥ - k∥ plane. One can then calculate the theoretical power spectrum in the window which can be directly compared with observations. The analysis should have implications for avoiding any bias in the parameter constraints using 21 cm power spectrum data.

Stars and reionization: the cross-correlation of the 21 cm line and the near-infrared background

NASA Astrophysics Data System (ADS)

Fernandez, Elizabeth R.; Zaroubi, Saleem; Iliev, Ilian T.; Mellema, Garrelt; Jelić, Vibor

2014-05-01

With improving telescopes, it may now be possible to observe the Epoch of Reionization in multiple ways. We examine two of these observables - the excess light in the near-infrared background that may be due to high-redshift stars and ionized HII bubbles, and the 21 cm emission from neutral hydrogen. Because these two forms of emission should result from different, mutually exclusive regions, an anticorrelation should exist between them. We discuss the strengths of using cross-correlations between these observations to learn more about high-redshift star formation and reionization history. In particular, we create simulated maps of emission from both the near-infrared background and 21 cm emission. We find that these observations are anticorrelated, with the strongest anticorrelation originating from times when the universe is half ionized. This result is robust and does not depend on the properties of the stars themselves. Rather, it depends on the ionization history. Cross-correlations can provide redshift information, which the near-infrared background cannot provide alone. In addition, cross-correlations can help separate foreground emission from the true high-redshift component, making it possible to say with greater certainty that we are indeed witnessing the Epoch of Reionization.

The observable signature of late heating of the Universe during cosmic reionization.

PubMed

Fialkov, Anastasia; Barkana, Rennan; Visbal, Eli

2014-02-13

Models and simulations of the epoch of reionization predict that spectra of the 21-centimetre transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and the characteristic size of ionized bubbles. This is based on the assumption that the cosmic gas was heated by stellar remnants-particularly X-ray binaries-to temperatures well above the cosmic microwave background at that time (about 30 kelvin). Here we show instead that the hard spectra (that is, spectra with more high-energy photons than low-energy photons) of X-ray binaries make such heating ineffective, resulting in a delayed and spatially uniform heating that modifies the 21-centimetre signature of reionization. Rather than looking for a simple rise and fall of the large-scale fluctuations (peaking at several millikelvin), we must expect a more complex signal also featuring a distinct minimum (at less than a millikelvin) that marks the rise of the cosmic mean gas temperature above the microwave background. Observing this signal, possibly with radio telescopes in operation today, will demonstrate the presence of a cosmic background of hard X-rays at that early time.

Modelling the 21-cm Signal from the Epoch of Reionization and Cosmic Dawn

NASA Astrophysics Data System (ADS)

Choudhury, T. Roy; Datta, Kanan; Majumdar, Suman; Ghara, Raghunath; Paranjape, Aseem; Mondal, Rajesh; Bharadwaj, Somnath; Samui, Saumyadip

2016-12-01

Studying the cosmic dawn and the epoch of reionization through the redshifted 21-cm line are among the major science goals of the SKA1. Their significance lies in the fact that they are closely related to the very first stars in the Universe. Interpreting the upcoming data would require detailed modelling of the relevant physical processes. In this article, we focus on the theoretical models of reionization that have been worked out by various groups working in India with the upcoming SKA in mind. These models include purely analytical and semi-numerical calculations as well as fully numerical radiative transfer simulations. The predictions of the 21-cm signal from these models would be useful in constraining the properties of the early galaxies using the SKA data.

Themes of grief.

PubMed

Carter, S L

1989-01-01

A thematic analysis of 30 narrative accounts of bereavement revealed nine themes that included five core themes in bereavement--being stopped, hurting, missing, holding, and seeking; three meta-themes about bereavement--change, expectations, and inexpressibility; and a contextual theme--personal history. The themes were compared with three theoretical perspectives on bereavement by Freud, Kübler-Ross, and one defined as existential-phenomenological. Features of bereavement that are dissimilar or unaddressed by the theoretical perspectives were: (a) the quality of grief's changing character, including "waves" and intense pain which may be triggered years after the death; (b) holding, an individual process of preserving the fact and meaning of the loved one's existence; (c) expectations, both social and personal, as to how the bereaved should be overlaying the experience; and (d) the critical importance of personal history in affecting the quality and meaning of individual bereavement.

Leadership mindset in mental health.

PubMed

Ng, Lillian; Steane, Richard; Scollay, Natalie

2018-02-01

The objective of this study was to explore the concept of mindset for psychiatrists who are considering stepping into the leadership arena. Qualitative themes were extracted from dialogue on leadership development at a Royal Australian and New Zealand College of Psychiatrists forum for early career psychiatrists. Three key themes were identified: adapting to a professional identity as psychiatrists; developing a mindset for leadership; and acting intentionally to seek opportunities for leadership. Shifts in professional identity occur in the transition from trainee to specialist as early career psychiatrists become increasingly aware of broad systemic factors in clinical care. The concept of a mindset, distinct from a skillset of knowledge and expertise, may be an emergent quality for psychiatrists who are seeking to develop their leadership potential.

"Putting one foot in front of the other": a qualitative study of emotional experiences and help-seeking in women with multiple sclerosis.

PubMed

Blundell Jones, Joanna; Walsh, Sue; Isaac, Claire

2014-12-01

Treatments for depression and anxiety in multiple sclerosis (MS) are effective but evidence suggests that individuals do not always seek help for emotional difficulties. This study explored how ten women with MS (aged 30-64), recruited via a hospital based MS clinic, coped with and understood their emotions. The semi-structured interviews were analysed using interpretative phenomenological analysis. Eight participants discussed the analytic process and themes. Four overarching themes emerged: Disclosure stress, Uncomfortable dependence, Facing deterioration and One step at a time. The women struggled emotionally with many aspects of living with MS yet coping alone provided a way of defying MS and maintaining independence and control. The women needed emotional support but reported thinking others either did not notice or understand; their emotions often felt invisible. More holistic care from services was desired. Non help-seeking for distress was partially influenced by a desire to keep things "normal" and a lack of knowledge regarding service provision.

"I Want a Second Chance": Experiences of African American Fathers in Reentry.

PubMed

Dill, LeConté J; Mahaffey, Carlos; Mosley, Tracey; Treadwell, Henrie; Barkwell, Fabeain; Barnhill, Sandra

2016-11-01

With over 700,000 people on average released from prison each year to communities, greater attention is warranted on the experiences and needs of those who are parents and seeking to develop healthy relationships with their children and families. This study seeks to explore the experiences of African American fathers in reentry. Qualitative data from 16 African American men enrolled in a fellowship program for fathers were collected from a focus group and analyzed for common themes and using standpoint theory. Four themes emerged that focused on fathers' commitment toward healthy and successful reintegration postincarceration: redemption, employment, health care, and social support. Focus group participants actively strive to develop and rebuild healthy relationships with their children through seeking gainful employment and through bonding with like-minded peers. Barriers in accessing health care are also discussed. Research findings may inform future programs and policies related to supporting fathers and their children in reentry. © The Author(s) 2015.

CRITICAL STAR FORMATION RATES FOR REIONIZATION: FULL REIONIZATION OCCURS AT REDSHIFT z Almost-Equal-To 7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael Shull, J.; Harness, Anthony; Trenti, Michele

We assess the probable redshift (z{sub rei} Almost-Equal-To 7) for full reionization of the intergalactic medium (IGM) using a prescription for the comoving star formation rate (SFR) density ({rho}-dot{sub SFR}) required to maintain photoionization against recombination. Our newly developed online reionization simulator allows users to assess the required SFR and ionization histories, using a variety of assumptions for galactic and stellar populations, IGM clumping factor and temperature, and Lyman continuum (LyC) escape fraction. The decline in high-redshift galaxy candidates and Ly{alpha} emitters at z = 6-8 suggests a rising neutral fraction, with reionization at z {approx}> 7 increasingly difficult owingmore » to increased recombination rates and constraints from the ionizing background and LyC mean free path. The required rate is {rho}-dot{sub SFR}{approx}(.018 M{sub sun}yr{sup -1}Mpc{sup -3})[(1+z)/8]{sup 3}(C{sub H}/3)(0.2/f{sub esc})T{sub 4}{sup -0.845} scaled to fiducial values of clumping factor C{sub H} = 3, escape fraction f{sub esc} = 0.2, electron temperature T{sub e} = 10{sup 4} K, and low-metallicity initial mass functions (IMFs) and stellar atmospheres. Our hydrodynamical + N-body simulations find a mean clumping factor C{sub H} Almost-Equal-To (2.9)[(1 + z)/6]{sup -1.1} in the photoionized, photoheated filaments at z = 5-9. The critical SFR could be reduced by increasing the minimum stellar mass, invoking a top-heavy IMF, or systematically increasing f{sub esc} at high z. The cosmic microwave background optical depth, {tau}{sub e} = 0.088 {+-} 0.015, could be explained by full reionization, producing {tau}{sub e} = 0.050 back to z{sub rei} Almost-Equal-To 7, augmented by {Delta}{tau}{sub e} Almost-Equal-To 0.01-0.04 in a partially ionized IGM at z > 7. In this scenario, the strongest 21 cm signal should occur at redshifted frequencies 124-167 MHz owing to IGM heating over an interval {Delta}z Almost-Equal-To 3 in the range z Almost-Equal-To 7.5-10.5.« less

Lyman Continuum Escape Fraction of Star-forming Dwarf Galaxies at z ˜ 1

NASA Astrophysics Data System (ADS)

Rutkowski, Michael J.; Scarlata, Claudia; Haardt, Francesco; Siana, Brian; Henry, Alaina; Rafelski, Marc; Hayes, Matthew; Salvato, Mara; Pahl, Anthony J.; Mehta, Vihang; Beck, Melanie; Malkan, Matthew; Teplitz, Harry I.

2016-03-01

To date, no direct detection of Lyman continuum emission has been measured for intermediate-redshift (z˜ 1) star-forming galaxies. We combine Hubble Space Telescope grism spectroscopy with GALEX UV and ground-based optical imaging to extend the search for escaping Lyman continuum to a large (˜600) sample of z˜ 1 low-mass ({log}(\\bar{M}) ≃ 9.3{M}⊙ ), moderately star-forming (\\bar{{{\\Psi }}} ≲ 10{M}⊙ yr-1) galaxies selected initially on Hα emission. The characteristic escape fraction of LyC from star-forming galaxies (SFGs) that populate this parameter space remains weakly constrained by previous surveys, but these faint (sub-L⋆) SFGs are assumed to play a significant role in the reionization of neutral hydrogen in the intergalactic medium (IGM) at high redshift z\\gt 6. We do not make an unambiguous detection of escaping LyC radiation from this z˜ 1 sample, individual non-detections to constrain the absolute Lyman continuum escape fraction, {f}{esc} \\lt 2.1% (3σ). We measure an upper limit of {f}{esc} \\lt 9.6% from a sample of SFGs selected on high Hα equivalent width (EW \\gt 200 {{\\mathringA }}), which are thought to be close analogs of high redshift sources of reionization. For reference, we also present an emissivity-weighted escape fraction that is useful for measuring the general contribution SFGs to the ionizing UV background. In the discussion, we consider the implications of these intermediate redshift constraints for the reionization of hydrogen in the IGM at high (z\\gt 6) redshift. If we assume our z˜ 1 SFGs, for which we measure this emissivity-weighted {f}{esc}, are analogs to the high redshift sources of reionization, we find it is difficult to reconcile reionization by faint ({M}{UV}≲ -13) SFGs with a low escape fraction ({f}{esc} \\lt 3%), with constraints from independent high redshift observations. If {f}{esc} evolves with redshift, reionization by SFGs may be consistent with observations from Planck.

Focus on Infants & Toddlers (Ages 0-3): A Quarterly Newsletter for the Education Community, 1999-2000.

ERIC Educational Resources Information Center

Barry, Virginia M., Ed.; Cantor, Patricia, Ed.

2000-01-01

These four quarterly newsletter issues address various topics of interest to child caregivers. Each issue focuses on a theme and includes articles on that theme, along with regular news or vice president's columns. The Fall 1999 issue addresses family play and seeks to encourage families to regard play as a way of relaxing and finding contentment…

Designing Successful Next-Generation Instruments to Detect the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan; Hydrogen Epoch of Reionization Array (HERA) team, Murchison Widefield Array (MWA) team

2018-01-01

The Epoch of Reionization (EoR) signifies a period of intense evolution of the Inter-Galactic Medium (IGM) in the early Universe caused by the first generations of stars and galaxies, wherein they turned the neutral IGM to be completely ionized by redshift ≥ 6. This important epoch is poorly explored to date. Measurement of redshifted 21 cm line from neutral Hydrogen during the EoR is promising to provide the most direct constraints of this epoch. Ongoing experiments to detect redshifted 21 cm power spectrum during reionization, including the Murchison Widefield Array (MWA), Precision Array for Probing the Epoch of Reionization (PAPER), and the Low Frequency Array (LOFAR), appear to be severely affected by bright foregrounds and unaccounted instrumental systematics. For example, the spectral structure introduced by wide-field effects, aperture shapes and angular power patterns of the antennas, electrical and geometrical reflections in the antennas and electrical paths, and antenna position errors can be major limiting factors. These mimic the 21 cm signal and severely degrade the instrument performance. It is imperative for the next-generation of experiments to eliminate these systematics at their source via robust instrument design. I will discuss a generic framework to set cosmologically motivated antenna performance specifications and design strategies using the Precision Radio Interferometry Simulator (PRISim) -- a high-precision tool that I have developed for simulations of foregrounds and the instrument transfer function intended primarily for 21 cm EoR studies, but also broadly applicable to interferometer-based intensity mapping experiments. The Hydrogen Epoch of Reionization Array (HERA), designed in-part based on this framework, is expected to detect the 21 cm signal with high significance. I will present this framework and the simulations, and their potential for designing upcoming radio instruments such as HERA and the Square Kilometre Array (SKA).

An Accurate Measurement of the IGM HeII Lyman Alpha Forest toward a Newly Discovered UV-bright Quasar at z>3.5

NASA Astrophysics Data System (ADS)

Worseck, Gabor

2016-10-01

The advent of GALEX and COS have revolutionized our view of HeII reionization, the final major phase transition of the intergalactic medium. COS spectra of the HeII Lyman alpha forest have confirmed with high confidence the high HeII transmission that signifies the completion of HeII reionization at z 2.7. However, the handful of z>3.5 quasars observed to date show a set of HeII transmission 'spikes' and larger regions with non-zero transmission that suggest HeII reionization was well underway by z=4. This is in striking conflict with predictions from state-of-the-art radiative transfer simulations of a HeII reionization driven by bright quasars. Explaining these measurements may require either faint quasars or more exotic sources of hard photons at z>4, with concomitant implications for HI reionization. We propose here to observe J2354-2033, an FUV-bright quasar at z=3.786 that we recently discovered in a dedicated survey for likely HeII-transmitting quasars. With this COS/G140L spectrum, we would confirm that the quasar is valuable for studies of the HeII Lyman alpha forest by identifying possible interloping low-z HI absorbers, provide accurate measurements of the IGM HeII opacity, and provide only the third z>3.5 sightline that would allow for high-resolution G130M spectroscopy before the end of HST's mission. The proposed observations would mark only the fourth observation of the HeII Lyman alpha forest at z>3.7 and the source would be the 2nd-brightest known on the sky at these redshifts.

Intensity Mapping of the [CII] Fine Structure Line during the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Gong, Yan; Cooray, A.; Silva, M.; Santos, M. G.; Bock, J.; Bradford, M.; Zemcov, M.

2012-01-01

The atomic CII fine-structure line is one of the brightest lines in a typical star-forming galaxy spectrum with a luminosity 0.1% to 1% of the bolometric luminosity. It is otentially a reliable tracer of the dense gas distribution at high edshifts and could provide an additional probe to the era of reionization. By taking into account of the spontaneous, stimulated and collisional emission of the CII line, we calculate the spin temperature and the mean intensity as a function of the redshift. When averaged over a cosmologically large volume, we find that the CII emission from ionized carbon in individual galaxies is larger than the signal generated by carbon in the intergalactic medium (IGM). Assuming that the CII luminosity is proportional to the carbon mass in dark matter halos, we also compute the power spectrum of the CII line intensity at various redshifts. In order to avoid the contamination from CO rotational lines at low redshift when targeting a CII survey at high redshifts, we propose the cross-correlation of CII and 21-cm line emission from high redshifts. To explore the detectability of the CII signal from reionization, we also evaluate the expected errors on the CII power spectrum and CII-21 cm cross power spectrum based on the design of the future milimeter surveys. We note that the CII-21 cm cross power spectrum contains interesting features that captures physics during reionization, including the ionized bubble sizes and the mean ionization fraction, which are challenging to measure from 21-cm data alone. We propose an instrumental concept for the reionization CII experiment targeting the frequency range of 200 to 300 GHz with 1, 3 and 10 meter apertures and a bolometric spectrometer array with 64 independent spectral pixels with about 20,000 bolometers.

Dark-ages reionization and galaxy formation simulation - IV. UV luminosity functions of high-redshift galaxies

NASA Astrophysics Data System (ADS)

Liu, Chuanwu; Mutch, Simon J.; Angel, P. W.; Duffy, Alan R.; Geil, Paul M.; Poole, Gregory B.; Mesinger, Andrei; Wyithe, J. Stuart B.

2016-10-01

In this paper, we present calculations of the UV luminosity function (LF) from the Dark-ages Reionization And Galaxy-formation Observables from Numerical Simulations project, which combines N-body, semi-analytic and seminumerical modelling designed to study galaxy formation during the Epoch of Reionization. Using galaxy formation physics including supernova feedback, the model naturally reproduces the UV LFs for high-redshift star-forming galaxies from z ˜ 5 through to z ˜ 10. We investigate the luminosity-star formation rate (SFR) relation, finding that variable SFR histories of galaxies result in a scatter around the median relation of 0.1-0.3 dex depending on UV luminosity. We find close agreement between the model and observationally derived SFR functions. We use our calculated luminosities to investigate the LF below current detection limits, and the ionizing photon budget for reionization. We predict that the slope of the UV LF remains steep below current detection limits and becomes flat at MUV ≳ -14. We find that 48 (17) per cent of the total UV flux at z ˜ 6 (10) has been detected above an observational limit of MUV ˜ -17, and that galaxies fainter than MUV ˜ -17 are the main source of ionizing photons for reionization. We investigate the luminosity-stellar mass relation, and find a correlation for galaxies with MUV < -14 that has the form M_{ast } ∝ 10^{-0.47M_UV}, in good agreement with observations, but which flattens for fainter galaxies. We determine the luminosity-halo mass relation to be M_vir ∝ 10^{-0.35M_UV}, finding that galaxies with MUV = -20 reside in host dark matter haloes of 1011.0±0.1 M⊙ at z ˜ 6, and that this mass decreases towards high redshift.

ON THE PROPER USE OF THE REDUCED SPEED OF LIGHT APPROXIMATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y., E-mail: gnedin@fnal.gov

I show that the reduced speed of light (RSL) approximation, when used properly (i.e., as originally designed—only for local sources but not for the cosmic background), remains a highly accurate numerical method for modeling cosmic reionization. Simulated ionization and star formation histories from the “Cosmic Reionization on Computers” project are insensitive to the adopted value of the RSL for as long as that value does not fall below about 10% of the true speed of light. A recent claim of the failure of the RSL approximation in the Illustris reionization model appears to be due to the effective speed ofmore » light being reduced in the equation for the cosmic background too and hence illustrates the importance of maintaining the correct speed of light in modeling the cosmic background.« less

Sub-Saharan African migrant youths' help-seeking barriers and facilitators for mental health and substance use problems: a qualitative study.

PubMed

McCann, Terence V; Mugavin, Janette; Renzaho, Andre; Lubman, Dan I

2016-08-02

Many young migrants and their parents are reluctant to seek help for mental health and substance use problems. Help-seeking delays can result in longer duration of untreated problems and poorer outcomes. In this study, we aimed to identify the help-seeking barriers and facilitators for anxiety, depression and alcohol and drug use problems in young people from recently established sub-Saharan African migrant communities. A qualitative study, incorporating individual, in-depth interviews and focus group discussions, was undertaken in Melbourne, Australia. Twenty-eight young sub-Saharan African migrants participated in the individual interviews, and 41 sub-Saharan African-born parents and key community leaders participated in 4 focus groups. All participants were aged 16 years or over. A thematic analysis of the data was undertaken. Themes and related sub-themes were abstracted from the data, reflecting the young people's, parents' and key community leaders' beliefs about barriers and facilitators to help-seeking for mental health and substance use problems. Four help-seeking barriers were identified: stigma of mental illness, lack of mental health literacy in parents and young people, lack of cultural competency of formal help sources, and financial costs deterring access. Five help-seeking facilitators were abstracted: being open with friends and family, strong community support systems, trustworthiness and confidentiality of help-sources, perceived expertise of formal help-sources, increasing young people's and parents' mental health literacy. Programs that identify and build on help-seeking facilitators while addressing help-seeking barriers are needed to address mental health issues among young sub-Saharan African migrants. Strategies to address help-seeking barriers should consider counteracting stigma and increasing mental health literacy in sub-Saharan African communities, increasing health providers' cultural competency and perceived trustworthiness, and addressing financial barriers to accessing services.

Sensitivity of the Hydrogen Epoch of Reionization Array and its build-out stages to one-point statistics from redshifted 21 cm observations

NASA Astrophysics Data System (ADS)

Kittiwisit, Piyanat; Bowman, Judd D.; Jacobs, Daniel C.; Beardsley, Adam P.; Thyagarajan, Nithyanandan

2018-03-01

We present a baseline sensitivity analysis of the Hydrogen Epoch of Reionization Array (HERA) and its build-out stages to one-point statistics (variance, skewness, and kurtosis) of redshifted 21 cm intensity fluctuation from the Epoch of Reionization (EoR) based on realistic mock observations. By developing a full-sky 21 cm light-cone model, taking into account the proper field of view and frequency bandwidth, utilizing a realistic measurement scheme, and assuming perfect foreground removal, we show that HERA will be able to recover statistics of the sky model with high sensitivity by averaging over measurements from multiple fields. All build-out stages will be able to detect variance, while skewness and kurtosis should be detectable for HERA128 and larger. We identify sample variance as the limiting constraint of the measurements at the end of reionization. The sensitivity can also be further improved by performing frequency windowing. In addition, we find that strong sample variance fluctuation in the kurtosis measured from an individual field of observation indicates the presence of outlying cold or hot regions in the underlying fluctuations, a feature that can potentially be used as an EoR bubble indicator.

Where Are All of the Gas-bearing Local Dwarf Galaxies? Quantifying Possible Impacts of Reionization

NASA Astrophysics Data System (ADS)

Tollerud, Erik J.; Peek, J. E. G.

2018-04-01

We present an approach for comparing the detections and non-detections of Local Group (LG) dwarf galaxies in large H I surveys to the predictions of a suite of n-body simulations of the LG. This approach depends primarily on a set of empirical scaling relations to connect the simulations to the observations, rather than making strong theoretical assumptions. We then apply this methodology to the Galactic Arecibo L-band Feed Array Hi (GALFA-HI) Compact Cloud Catalog (CCC), and compare it to the suite Exploring the Local Volume In Simulations (ELVIS) of simulations. This approach reveals a strong tension between the naïve results of the model and the observations: while there are no LG dwarfs in the GALFA-HI CCC, the simulations predict ∼10. Applying a simple model of reionization can resolve this tension by preventing low-mass halos from forming gas. However, and if this effect operates as expected, the observations provide a constraint on the mass scale of the dwarf galaxy that reionization impacts. Combined with the observed properties of Leo T, the halo virial mass scale at which reionization impacts dwarf galaxy gas content is constrained to be ∼ {10}8.5 {M}ȯ , independent of any assumptions about star formation.

The Motivations of Iranian Patients With Cardiovascular Disease to Seek Health Information: A Qualitative Study

PubMed Central

Gholami, Mohammad; Fallahi Khoshknab, Masoud; Khankeh, Hamid Reza; Ahmadi, Fazlollah; Maddah, Sadat Seyed Bagher; Mousavi Arfaa, Nazila

2016-01-01

Background Cardiovascular patients need information to preserve and promote their health, but not all of them have the necessary motivation to seek relevant health knowledge. Objectives The present study analyzed experiences of patients, family caregivers, and healthcare providers to explore the motivating factors that cause cardiovascular patients to seek important health information. Patients and Methods This study was conducted using a qualitative approach and conventional qualitative content analysis method. Thirty-six people, including 18 cardiovascular patients, 7 family caregivers, and 11 healthcare providers (from multidisciplinary backgrounds) participated in the study. The data were collected through semi-structured interviews and purposeful sampling and continued until data saturation. Data collection and analysis proceeded simultaneously and with constant comparison; this study was carried out from May 2012 to May 2013. Results During the analysis process, three main themes were extracted that characterized participants’ experiences, perceptions, and motivations to seek health information. The themes were “Optimizing quality of life, “Desire for personal rights to be respected,” and “Gaining confidence through consultation.” Conclusions Our findings showed that, through seeking information, patients try to achieve well-being and realize their personal rights as well as their right to security. They should also be encouraged to enhance their quality of life by using the Knowles’ learning theory to formulate their needs and learning priorities. PMID:27437128

Self-harm as a means to manage the public and private selves: A qualitative study of help seeking by adults

PubMed Central

Ogden, Jane; Bennett, Alice

2015-01-01

Adults (n = 25) completed online free text boxes about their self-harming behaviour. Thematic analysis identified three dominant themes: ‘managing the private self’, ‘managing the public self’ and ‘moving on’. Transcending these themes was the notion of thresholds of change. Self-harm enables people to manage both their private and public selves. When thresholds of change are surpassed, the public self communicates a need for help. Self-harm exists within a precarious balance of well-being and can be a form of self-care. Help seeking is instigated when this balance is disrupted and continued if it offers a better form of self-management than the individual’s own self-harming behaviour. PMID:28070372

Building a Progressive-Situational Model of Post-Diagnosis Information Seeking for Parents of Individuals With Down Syndrome

PubMed Central

Gibson, Amelia N.

2016-01-01

This grounded theory study used in-depth, semi-structured interview to examine the information-seeking behaviors of 35 parents of children with Down syndrome. Emergent themes include a progressive pattern of behavior including information overload and avoidance, passive attention, and active information seeking; varying preferences between tacit and explicit information at different stages; and selection of information channels and sources that varied based on personal and situational constraints. Based on the findings, the author proposes a progressive model of health information seeking and a framework for using this model to collect data in practice. The author also discusses the practical and theoretical implications of a responsive, progressive approach to understanding parents’ health information–seeking behavior. PMID:28462351

Simulating pre-galactic metal enrichment for JWST deep-field observations

NASA Astrophysics Data System (ADS)

Jaacks, Jason

2017-08-01

We propose to create a new suite of mesoscale cosmological volume simulations with custom built sub-grid physics in which we independently track the contribution from Population III and Population II star formation to the total metals in the interstellar medium (ISM) of the first galaxies, and in the diffuse IGM at an epoch prior to reionization. These simulations will fill a gap in our simulation knowledge about chemical enrichment in the pre-reionization universe, which is a crucial need given the impending observational push into this epoch with near-future ground and space-based telescopes. This project is the natural extension of our successful Cycle 24 theory proposal (HST-AR-14569.001-A; PI Jaacks) in which we developed a new Pop III star formation sub-grid model which is currently being utilized to study the baseline metal enrichment of pre-reionization systems.

Cosmic Reionization On Computers III. The Clumping Factor

DOE PAGES

Kaurov, Alexander A.; Gnedin, Nickolay Y.

2015-09-09

We use fully self-consistent numerical simulations of cosmic reionization, completed under the Cosmic Reionization On Computers project, to explore how well the recombinations in the ionized intergalactic medium (IGM) can be quantified by the effective "clumping factor." The density distribution in the simulations (and, presumably, in a real universe) is highly inhomogeneous and more-or-less smoothly varying in space. However, even in highly complex and dynamic environments, the concept of the IGM remains reasonably well-defined; the largest ambiguity comes from the unvirialized regions around galaxies that are over-ionized by the local enhancement in the radiation field ("proximity zones"). This ambiguity precludesmore » computing the IGM clumping factor to better than about 20%. Furthermore, we discuss a "local clumping factor," defined over a particular spatial scale, and quantify its scatter on a given scale and its variation as a function of scale.« less

Cosmic reionization on computers: The faint end of the galaxy luminosity function

DOE PAGES

Gnedin, Nickolay Y.

2016-07-01

Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

Constraint on the abundance of primordial black holes in dark matter from Planck data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Lu; Huang, Qing-Guo; Wang, Ke, E-mail: chenlu@itp.ac.cn, E-mail: huangqg@itp.ac.cn, E-mail: wangke@itp.ac.cn

We use Planck data released in 2015 to constrain the abundance of primordial black holes (PBHs) in dark matter in two different reionization models (one is the instantaneous reionization and the other is the asymmetric reionization), and significantly improve the existing upper limits on the abundance of PBHs by around two orders of magnitude. These new limits imply that the event rates of mergers of PBH binaries (Gpc{sup −3} yr{sup −1}) are less than 0.002 for M {sub pbh} = 30 M {sub ⊙}, 5 for M {sub pbh} = 10 M {sub ⊙} and 2000 for M {sub pbh}more » = 2 M {sub ⊙} at 95% confidence level (C.L.), and thus the gravitational-wave event GW150914 is very unlikely produced by the merger of a PBH binary.« less

On the proper use of the reduced speed of light approximation

DOE PAGES

Gnedin, Nickolay Y.

2016-12-07

I show that the Reduced Speed of Light (RSL) approximation, when used properly (i.e. as originally designed - only for the local sources but not for the cosmic background), remains a highly accurate numerical method for modeling cosmic reionization. Simulated ionization and star formation histories from the "Cosmic Reionization On Computers" (CROC) project are insensitive to the adopted value of the reduced speed of light for as long as that value does not fall below about 10% of the true speed of light. Here, a recent claim of the failure of the RSL approximation in the Illustris reionization model appearsmore » to be due to the effective speed of light being reduced in the equation for the cosmic background too, and, hence, illustrates the importance of maintaining the correct speed of light in modeling the cosmic background.« less

On the proper use of the reduced speed of light approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.

I show that the Reduced Speed of Light (RSL) approximation, when used properly (i.e. as originally designed - only for the local sources but not for the cosmic background), remains a highly accurate numerical method for modeling cosmic reionization. Simulated ionization and star formation histories from the "Cosmic Reionization On Computers" (CROC) project are insensitive to the adopted value of the reduced speed of light for as long as that value does not fall below about 10% of the true speed of light. Here, a recent claim of the failure of the RSL approximation in the Illustris reionization model appearsmore » to be due to the effective speed of light being reduced in the equation for the cosmic background too, and, hence, illustrates the importance of maintaining the correct speed of light in modeling the cosmic background.« less

The X-rays of a bright QSO well within the epoch of reionization at z=7.54

NASA Astrophysics Data System (ADS)

Banados, Eduardo

2016-09-01

After almost a decade of intense search, our team has finally discovered a bright QSO well within the epoch of reionization, at z=7.54. This is by far the most distant QSO known (previous record: 7.08), at a cosmic age of 690 Myr, i.e., only 5% of our universe's current age. This is the first QSO whose spectrum shows clear evidence of an intergalactic medium that is >20% neutral and that reionization is underway. We propose Chandra observations of this unique object to (i) probe evolution of the X-ray-to-optical luminosity ratio (alpha-ox) to the highest accessible redshift; (ii) provide a more reliable estimate of the QSO's bolometric luminosity, and (iii) assess the feasibility of deeper Chandra and XMM observations for the upcoming cycles, which would allow us to test whether the first black holes are accreting at super-Eddington rates.

Cosmic Reionization On Computers III. The Clumping Factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaurov, Alexander A.; Gnedin, Nickolay Y.

We use fully self-consistent numerical simulations of cosmic reionization, completed under the Cosmic Reionization On Computers project, to explore how well the recombinations in the ionized intergalactic medium (IGM) can be quantified by the effective "clumping factor." The density distribution in the simulations (and, presumably, in a real universe) is highly inhomogeneous and more-or-less smoothly varying in space. However, even in highly complex and dynamic environments, the concept of the IGM remains reasonably well-defined; the largest ambiguity comes from the unvirialized regions around galaxies that are over-ionized by the local enhancement in the radiation field ("proximity zones"). This ambiguity precludesmore » computing the IGM clumping factor to better than about 20%. Furthermore, we discuss a "local clumping factor," defined over a particular spatial scale, and quantify its scatter on a given scale and its variation as a function of scale.« less

Cosmic reionization on computers. I. Design and calibration of simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y., E-mail: gnedin@fnal.gov

Cosmic Reionization On Computers is a long-term program of numerical simulations of cosmic reionization. Its goal is to model fully self-consistently (albeit not necessarily from the first principles) all relevant physics, from radiative transfer to gas dynamics and star formation, in simulation volumes of up to 100 comoving Mpc, and with spatial resolution approaching 100 pc in physical units. In this method paper, we describe our numerical method, the design of simulations, and the calibration of numerical parameters. Using several sets (ensembles) of simulations in 20 h {sup –1} Mpc and 40 h {sup –1} Mpc boxes with spatial resolutionmore » reaching 125 pc at z = 6, we are able to match the observed galaxy UV luminosity functions at all redshifts between 6 and 10, as well as obtain reasonable agreement with the observational measurements of the Gunn-Peterson optical depth at z < 6.« less

Cosmic reionization on computers: The faint end of the galaxy luminosity function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.

Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

COSMIC REIONIZATION ON COMPUTERS. III. THE CLUMPING FACTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaurov, Alexander A.; Gnedin, Nickolay Y., E-mail: kaurov@uchicago.edu, E-mail: gnedin@fnal.gov

We use fully self-consistent numerical simulations of cosmic reionization, completed under the Cosmic Reionization On Computers project, to explore how well the recombinations in the ionized intergalactic medium (IGM) can be quantified by the effective “clumping factor.” The density distribution in the simulations (and, presumably, in a real universe) is highly inhomogeneous and more-or-less smoothly varying in space. However, even in highly complex and dynamic environments, the concept of the IGM remains reasonably well-defined; the largest ambiguity comes from the unvirialized regions around galaxies that are over-ionized by the local enhancement in the radiation field (“proximity zones”). That ambiguity precludesmore » computing the IGM clumping factor to better than about 20%. We also discuss a “local clumping factor,” defined over a particular spatial scale, and quantify its scatter on a given scale and its variation as a function of scale.« less

The Effect of Antenna Position Errors on Redundant-Baseline Calibration of HERA

NASA Astrophysics Data System (ADS)

Orosz, Naomi; Dillon, Joshua; Ewall-Wice, Aaron; Parsons, Aaron; HERA Collaboration

2018-01-01

HERA (the Hydrogen Epoch of Reionization Array) is a large, highly-redundant radio interferometer in South Africa currently being built out to 350 14-m dishes. Its mission is to probe large scale structure during and prior to the epoch of reionization using the 21 cm hyperfine transition of neutral hydrogen. The array is designed to be calibrated using redundant baselines of known lengths. However, the dishes can deviate from ideal positions, with errors on the order of a few centimeters. This potentially increases foreground contamination of the 21 cm power spectrum in the cleanest part of Fourier space. The calibration algorithm treats groups of baselines that should be redundant, but are not due to position errors, as if they actually are. Accurate, precise calibration is critical because the foreground signals are 100,000 times stronger than the reionization signal. We explain the origin of this effect and discuss weighting strategies to mitigate it.

Planck and the reionization of the universe

NASA Astrophysics Data System (ADS)

Crill, Brendan

2016-03-01

Planck is the third-generation satellite aimed at measuring the cosmic microwave background, a relic of the hot big bang. Planck's temperature and polarization maps of the millimeter-wave sky have constrained parameters of the standard lambda-CDM model of cosmology to incredible precision, and have provided constraints on inflation in the very early universe. Planck's all-sky survey of polarization in seven frequency bands can remove contamination from nearby Galactic emission and constrain the optical depth of the reionized Universe, giving insight into the properties of the earliest star formation. The final 2016 data release from Planck will include a refined optical depth measurement using the full sensitivity of both the High Frequency and Low Frequency instruments. I present the status of the reionization measurement and discuss future prospects for further measurements of the early Universe with the CMB from Planck and future space and suborbital platforms.

Young Men, Help-Seeking, and Mental Health Services: Exploring Barriers and Solutions

PubMed Central

Lynch, Louise; Long, Maggie; Moorhead, Anne

2016-01-01

International research has identified young men as reluctant to seek help for mental health problems. This research explored barriers and solutions to professional help seeking for mental health problems among young men living in the North West of Ireland. A qualitative approach, using two focus groups with six participants each and five face-to-face interviews, was conducted with men aged 18 to 24 years (total N = 17). Data were analyzed using thematic analysis. Seven key themes of barriers to professional help seeking were identified: “acceptance from peers,” “personal challenges,” “cultural and environmental influences,” “self-medicating with alcohol,” “perspectives around seeking professional help,” “fear of homophobic responses,” and “traditional masculine ideals.” Five key themes of solutions to these barriers included “tailored mental health advertising,” “integrating mental health into formal education,” “education through semiformal support services,” “accessible mental health care,” and “making new meaning.” Interesting findings on barriers include fear of psychiatric medication, fear of homophobic responses from professionals, the legacy of Catholic attitudes, and the genuine need for care. This study offers an in-depth exploration of how young men experience barriers and uniquely offers solutions identified by participants themselves. Youth work settings were identified as a resource for engaging young men in mental health work. Young men can be encouraged to seek help if services and professionals actively address barriers, combining advertising, services, and education, with particular attention and respect to how and when young men seek help and with whom they want to share their problems. PMID:27365212

Health care seeking among Mexican American men.

PubMed

Sobralske, Mary C

2006-04-01

This focused ethnography explored health care seeking beliefs and behaviors of Mexican American men living in south central Washington State. Data collection included interviews with 36 research participants living in the community, participant observation in the research setting, and examination of ethnographic documents and cultural artifacts. Four major themes were identified: the identity of manhood dictates health care seeking, health means being able to be a man by fulfilling cultural obligations, illness means not being able to be a man, and men seek health care when their manhood is threatened or impaired. Machismo, the cultural concept of manliness, persisted among men despite the level of acculturation and other factors. Women influenced men's health care seeking behaviors. To fulfill their obligations, men must stay healthy and seek care when needed. Knowing when and why men do not seek health care enables nurses to better understand and serve the Mexican American community.

Seeking help for perinatal psychological distress: a meta-synthesis of women's experiences.

PubMed

Button, Susan; Thornton, Alexandra; Lee, Suzanne; Shakespeare, Judy; Ayers, Susan

2017-10-01

Women may not seek help for perinatal psychological distress, despite regular contact with primary care services. Barriers include ignorance of symptoms, inability to disclose distress, others' attitudes, and cultural expectations. Much of the evidence has been obtained from North American populations and may not, therefore, extrapolate to the UK. To understand the factors affecting women's decision to seek help for perinatal distress. Meta-synthesis of the available published qualitative evidence on UK women's experiences of seeking help for perinatal distress. Systematic searches were conducted in accordance with PRISMA guidelines. Databases searched were PubMed, Scopus, PsycINFO, PsycARTICLES, CINAHL, and Academic Search Complete. Searches of grey literature and references were also conducted. Studies were eligible for inclusion if they reported qualitative data on UK women's experiences of perinatal distress and contact with healthcare professionals. The synthesis was conducted using meta-ethnography. In all, 24 studies were eligible for inclusion. Metasynthesis identified three main themes: identifying a problem, the influence of healthcare professionals, and stigma. These themes build on current understanding of help seeking by identifying the need for women to be able to frame their experience, for healthcare professionals to educate women about their roles, the need for continuity of care, and the way that being seen as a 'bad mother' causes women to self-silence. Perinatal care provision needs to allow for continuity of care and for staff training that facilitates awareness of factors that influence women's help seeking. Further research is required, particularly in relation to effective means of identifying perinatal psychological distress. © British Journal of General Practice 2017.

ETHOS - an effective theory of structure formation: predictions for the high-redshift Universe - abundance of galaxies and reionization

NASA Astrophysics Data System (ADS)

Lovell, Mark R.; Zavala, Jesús; Vogelsberger, Mark; Shen, Xuejian; Cyr-Racine, Francis-Yan; Pfrommer, Christoph; Sigurdson, Kris; Boylan-Kolchin, Michael; Pillepich, Annalisa

2018-07-01

We contrast predictions for the high-redshift galaxy population and reionization history between cold dark matter (CDM) and an alternative self-interacting dark matter model based on the recently developed ETHOS framework that alleviates the small-scale CDM challenges within the Local Group. We perform the highest resolution hydrodynamical cosmological simulations (a 36 Mpc3 volume with gas cell mass of ˜ 105 M_{⊙} and minimum gas softening of ˜180 pc) within ETHOS to date - plus a CDM counterpart - to quantify the abundance of galaxies at high redshift and their impact on reionization. We find that ETHOS predicts galaxies with higher ultraviolet (UV) luminosities than their CDM counterparts and a faster build-up of the faint end of the UV luminosity function. These effects, however, make the optical depth to reionization less sensitive to the power spectrum cut-off: the ETHOS model differs from the CDM τ value by only 10 per cent and is consistent with Planck limits if the effective escape fraction of UV photons is 0.1-0.5. We conclude that current observations of high-redshift luminosity functions cannot differentiate between ETHOS and CDM models, but deep James Webb Space Telescope surveys of strongly lensed, inherently faint galaxies have the potential to test non-CDM models that offer attractive solutions to CDM's Local Group problems.

On the use of seminumerical simulations in predicting the 21-cm signal from the epoch of reionization

NASA Astrophysics Data System (ADS)

Majumdar, Suman; Mellema, Garrelt; Datta, Kanan K.; Jensen, Hannes; Choudhury, T. Roy; Bharadwaj, Somnath; Friedrich, Martina M.

2014-10-01

We present a detailed comparison of three different simulations of the epoch of reionization (EoR). The radiative transfer simulation (C2-RAY) among them is our benchmark. Radiative transfer codes can produce realistic results, but are computationally expensive. We compare it with two seminumerical techniques: one using the same haloes as C2-RAY as its sources (Sem-Num), and one using a conditional Press-Schechter scheme (CPS+GS). These are vastly more computationally efficient than C2-RAY, but use more simplistic physical assumptions. We evaluate these simulations in terms of their ability to reproduce the history and morphology of reionization. We find that both Sem-Num and CPS+GS can produce an ionization history and morphology that is very close to C2-RAY, with Sem-Num performing slightly better compared to CPS+GS. We also study different redshift-space observables of the 21-cm signal from EoR: the variance, power spectrum and its various angular multipole moments. We find that both seminumerical models perform reasonably well in predicting these observables at length scales relevant for present and future experiments. However, Sem-Num performs slightly better than CPS+GS in producing the reionization history, which is necessary for interpreting the future observations. The CPS+GS scheme, however, has the advantage that it is not restricted by the mass resolution of the dark matter density field.

The Cosmology Large Angular Scale Surveyor (CLASS)

NASA Astrophysics Data System (ADS)

Cleary, Joseph

2018-01-01

The Cosmology Large Angular Scale Surveyor (CLASS) is an array of four telescopes designed to measure the polarization of the Cosmic Microwave Background. CLASS aims to detect the B-mode polarization from primordial gravitational waves predicted by cosmic inflation theory, as well as the imprint left by reionization upon the CMB E-mode polarization. This will be achieved through a combination of observing strategy and state-of-the-art instrumentation. CLASS is observing 70% of the sky to characterize the CMB at large angular scales, which will measure the entire CMB power spectrum from the reionization peak to the recombination peak. The four telescopes operate at frequencies of 38, 93, 145, and 217 GHz, in order to estimate Galactic synchrotron and dust foregrounds while avoiding atmospheric absorption. CLASS employs rapid polarization modulation to overcome atmospheric and instrumental noise. Polarization sensitive cryogenic detectors with low noise levels provide CLASS the sensitivity required to constrain the tensor-to-scalar ratio down to levels of r ~ 0.01 while also measuring the optical depth the reionization to sample-variance levels. These improved constraints on the optical depth to reionization are required to pin down the mass of neutrinos from complementary cosmological data. CLASS has completed a year of observations at 38 GHz and is in the process of deploying the rest of the telescope array. This poster provides an overview and update on the CLASS science, hardware and survey operations.

21CMMC with a 3D light-cone: the impact of the co-evolution approximation on the astrophysics of reionization and cosmic dawn

NASA Astrophysics Data System (ADS)

Greig, Bradley; Mesinger, Andrei

2018-07-01

We extend 21CMMC, a Monte Carlo Markov Chain sampler of 3D reionization simulations, to perform parameter estimation directly on 3D light-cones of the cosmic 21 cm signal. This brings theoretical analysis closer to the tomographic 21 cm observations achievable with next generation interferometers like the Hydrogen Epoch of Reionization Array and the Square Kilometre Array. Parameter recovery can therefore account for modes that evolve with redshift/frequency. Additionally, simulated data can be more easily corrupted to resemble real data. Using the light-cone version of 21CMMC, we quantify the biases in the recovered astrophysical parameters if we use the 21 cm power spectrum from the co-evolution approximation to fit a 3D light-cone mock observation. While ignoring the light-cone effect under most assumptions will not significantly bias the recovered astrophysical parameters, it can lead to an underestimation of the associated uncertainty. However, significant biases (˜few - 10σ) can occur if the 21 cm signal evolves rapidly (i.e. the epochs of reionization and heating overlap significantly), and (i) foreground removal is very efficient, allowing large physical scales (k ≲ 0.1 Mpc-1) to be used in the analysis or (ii) theoretical modelling is accurate to within ˜10 per cent in the power spectrum amplitude.

Distinguishing models of reionization using future radio observations of 21-cm 1-point statistics

NASA Astrophysics Data System (ADS)

Watkinson, C. A.; Pritchard, J. R.

2014-10-01

We explore the impact of reionization topology on 21-cm statistics. Four reionization models are presented which emulate large ionized bubbles around overdense regions (21CMFAST/global-inside-out), small ionized bubbles in overdense regions (local-inside-out), large ionized bubbles around underdense regions (global-outside-in) and small ionized bubbles around underdense regions (local-outside-in). We show that first generation instruments might struggle to distinguish global models using the shape of the power spectrum alone. All instruments considered are capable of breaking this degeneracy with the variance, which is higher in outside-in models. Global models can also be distinguished at small scales from a boost in the power spectrum from a positive correlation between the density and neutral-fraction fields in outside-in models. Negative skewness is found to be unique to inside-out models and we find that pre-Square Kilometre Array (SKA) instruments could detect this feature in maps smoothed to reduce noise errors. The early, mid- and late phases of reionization imprint signatures in the brightness-temperature moments, we examine their model dependence and find pre-SKA instruments capable of exploiting these timing constraints in smoothed maps. The dimensional skewness is introduced and is shown to have stronger signatures of the early and mid-phase timing if the inside-out scenario is correct.

Reionization and the Abundance of Galactic Satellites

NASA Astrophysics Data System (ADS)

Bullock, James S.; Kravtsov, Andrey V.; Weinberg, David H.

2000-08-01

One of the main challenges facing standard hierarchical structure formation models is that the predicted abundance of Galactic subhalos with circular velocities vc~10-30 km s-1 is an order of magnitude higher than the number of satellites actually observed within the Local Group. Using a simple model for the formation and evolution of dark halos, based on the extended Press-Schechter formalism and tested against N-body results, we show that the theoretical predictions can be reconciled with observations if gas accretion in low-mass halos is suppressed after the epoch of reionization. In this picture, the observed dwarf satellites correspond to the small fraction of halos that accreted substantial amounts of gas before reionization. The photoionization mechanism naturally explains why the discrepancy between predicted halos and observed satellites sets in at vc~30 km s-1, and for reasonable choices of the reionization redshift (zre~5-12) the model can reproduce both the amplitude and shape of the observed velocity function of galactic satellites. If this explanation is correct, then typical bright galaxy halos contain many low-mass dark matter subhalos. These might be detectable through their gravitational lensing effects, through their influence on stellar disks, or as dwarf satellites with very high mass-to-light ratios. This model also predicts a diffuse stellar component produced by large numbers of tidally disrupted dwarfs, perhaps sufficient to account for most of the Milky Way's stellar halo.

Physicians' pharmacogenomics information needs and seeking behavior: a study with case vignettes.

PubMed

Heale, Bret S E; Khalifa, Aly; Stone, Bryan L; Nelson, Scott; Del Fiol, Guilherme

2017-08-01

Genetic testing, especially in pharmacogenomics, can have a major impact on patient care. However, most physicians do not feel that they have sufficient knowledge to apply pharmacogenomics to patient care. Online information resources can help address this gap. We investigated physicians' pharmacogenomics information needs and information-seeking behavior, in order to guide the design of pharmacogenomics information resources that effectively meet clinical information needs. We performed a formative, mixed-method assessment of physicians' information-seeking process in three pharmacogenomics case vignettes. Interactions of 6 physicians' with online pharmacogenomics resources were recorded, transcribed, and analyzed for prominent themes. Quantitative data included information-seeking duration, page navigations, and number of searches entered. We found that participants searched an average of 8 min per case vignette, spent less than 30 s reviewing specific content, and rarely refined search terms. Participants' information needs included a need for clinically meaningful descriptions of test interpretations, a molecular basis for the clinical effect of drug variation, information on the logistics of carrying out a genetic test (including questions related to cost, availability, test turn-around time, insurance coverage, and accessibility of expert support).Also, participants sought alternative therapies that would not require genetic testing. This study of pharmacogenomics information-seeking behavior indicates that content to support their information needs is dispersed and hard to find. Our results reveal a set of themes that information resources can use to help physicians find and apply pharmacogenomics information to the care of their patients.

Health-seeking behaviour in Pakistan: a narrative review of the existing literature.

PubMed

Anwar, M; Green, J; Norris, P

2012-06-01

This narrative review was carried out to collate the work of researchers on health-seeking behaviour in Pakistan, to discuss the methods used, highlight the emerging themes and identify areas that have yet to be studied. Review. An overview of studies on health-seeking behaviour in Pakistan, found via searches on scholarly databases intended to locate material of medical and anthropological relevance. In total, 29 articles were reviewed with a range of different methodologies. A retrospective approach was the most common. A variety of medical conditions have been studied in terms of health-seeking behaviour of people experiencing such conditions. However, a wide range of chronic illnesses have yet to be studied. Nevertheless, some studies highlighting unusual issues such as snake bites and health-seeking behaviour of street children were also found. In terms of geographical area, the majority of studies reviewed were performed in the provinces of Sind and Punjab, with little research targeting the people from the two other provinces (Balochistan and Khyber Pakhtunkhwa) of Pakistan. Predominant utilization of private healthcare facilities, self-medication, involvement of traditional healers in the healthcare system, women's autonomy, and superstitions and fallacies associated with health-seeking behaviour were found to be the themes that repeatedly emerged in the literature reviewed. The sociocultural and religious background of Pakistan means that health-seeking behaviour resembles a mosaic. There is a need to improve the quality of service provided by the public healthcare sector and the recruitment of female staff. Traditional healers should be trained and integrated into the mainstream to provide adequate healthcare. Serious efforts are required to increase the awareness and educational level of the public, especially women in rural areas, in order to fight against myths and superstitions associated with health-seeking behaviour. Copyright © 2012 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Defense Acquisition Research Journal. Volume 19, Number 1, Issue 61, January 2012

DTIC Science & Technology

2012-01-01

format (author-date-page number form of citation) as outlined in the Publication Manual of the American Psycho- logical Association ( 6th Edition ). For all...other style questions, please refer to the Chicago Manual of Style (15th Edition ). Contributors are encouraged to seek the advice of a reference...theme editions . Please consult the DAU home page for current themes being solicited. See print schedule below. 2012 Due Date Publication Date July 1

Relic keV sterile neutrinos and reionization.

PubMed

Biermann, Peter L; Kusenko, Alexander

2006-03-10

A sterile neutrino with a mass of several keV can account for cosmological dark matter, as well as explain the observed velocities of pulsars. We show that x rays produced by the decays of these relic sterile neutrinos can boost the production of molecular hydrogen, which can speed up the cooling of gas and the early star formation, which can, in turn, lead to a reionization of the Universe at a high enough redshift to be consistent with the Wilkinson Microwave Anisotropy Probe results.

Understanding the medicines information-seeking behaviour and information needs of South African long-term patients with limited literacy skills.

PubMed

Patel, Sonal; Dowse, Ros

2015-10-01

Although much health information-seeking behaviour (HISB) research has been reported in patients with good literacy skills, little is known about HISB in patients with limited literacy skills served by under-resourced health-care systems. To investigate medicine information-seeking behaviour and information needs in patients with limited literacy. Using a question guide, four focus group discussions (FGDs) were conducted to explore themes related to information needs, information-seeking practices and awareness of and ability to utilize information sources. Twenty-two isiXhosa-speaking long-term patients with limited formal education were recruited from a primary health-care clinic in South Africa. Discussions were audio-recorded and transcribed verbatim. NVivo(®) was used for initial coding of transcripts. Codes were analysed, and potential themes and subthemes in the entire data set were identified and refined. The results of this study reflect a passive, disempowered patient. Poor awareness of information sources, lack of health-related knowledge and stigma contributed to a lack of information-seeking practice, thus potentially adversely influencing patient-provider interactions. Patients neither asked questions nor were encouraged to ask questions. All expressed an unmet need for information and a desire for receiving the illustrated written medicines-related information displayed in the FGDs. The main sources of information were health-care professionals, followed by family and friends. The significant level of patient disempowerment and passivity reported amongst patients underpinned their inability to actively seek information. Neither sources of information nor types of appropriate medicines information could be identified. Unmet information needs and a desire for information were reported. © 2013 John Wiley & Sons Ltd.

Health care seeking behaviours in pregnancy in rural Sindh, Pakistan: a qualitative study.

PubMed

Qureshi, Rahat Najam; Sheikh, Sana; Khowaja, Asif Raza; Hoodbhoy, Zahra; Zaidi, Shujaat; Sawchuck, Diane; Vidler, Marianne; Bhutta, Zulfiqar A; von Dadeslzen, Peter

2016-06-08

Pakistan has alarmingly high numbers of maternal mortality along with suboptimal care-seeking behaviour. It is essential to identify the barriers and facilitators that women and families encounter, when deciding to seek maternal care services. This study aimed to understand health-seeking patterns of pregnant women in rural Sindh, Pakistan. A qualitative study was undertaken in rural Sindh, Pakistan as part of a large multi-country study in 2012. Thirty three focus group discussions and 26 in-depth interviews were conducted with mothers [n = 173], male decision-makers [n = 64], Lady Health Workers [n = 64], Lady Health Supervisors [n = 10], Women Medical Officers [n = 9] and Traditional Birth Attendants [n = 7] in the study communities. A set of a priori themes regarding care-seeking during pregnancy and its complications as well as additional themes as they emerged from the data were used for analysis. Qualitative analysis was done using NVivo version 10. Women stated they usually visited health facilities if they experienced pregnancy complications or danger signs, such as heavy bleeding or headache. Findings revealed the importance of husbands and mothers-in-law as decision makers regarding health care utilization. Participants expressed that poor availability of transport, financial constraints and the unavailability of chaperones were important barriers to seeking care. In addition, private facilities were often preferred due to the perceived superior quality of services. Maternal care utilization was influenced by social, economic and cultural factors in rural Pakistani communities. The perceived poor quality care at public hospitals was a significant barrier for many women in accessing health services. If maternal lives are to be saved, policy makers need to develop processes to overcome these barriers and ensure easily accessible high-quality care for women in rural communities. NCT01911494.

Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

DOE PAGES

Parham, Paul E.; Waldock, Joanna; Christophides, George K.; ...

2015-02-16

Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is due not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but, perhaps most crucially, the multitude of epidemiological, ecological, and socioeconomic factors that drive VBD transmission, and this complexity has generated considerable debate over the last 10-15 years. Inmore » this article, and Theme Issue, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions, and, crucially, offer some solutions for the field moving forwards. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems. This Theme Issue seeks to cover both, reflected in the breadth and depth of the topics and VBD-systems considered, itself strongly indicative of the challenging, but necessary, multidisciplinary nature of this research field.« less

Barriers and Facilitators to Deaf Trauma Survivors' Help-Seeking Behavior: Lessons for Behavioral Clinical Trials Research.

PubMed

Anderson, Melissa L; Wolf Craig, Kelly S; Ziedonis, Douglas M

2017-01-01

Deaf individuals experience significant obstacles to participating in behavioral health research when careful consideration is not given to accessibility during the design of study methodology. To inform such considerations, we conducted an exploratory secondary analysis of a mixed-methods study that originally explored 16 Deaf trauma survivors' help-seeking experiences. Our objective was to identify key findings and qualitative themes from consumers' own words that could be applied to the design of behavioral clinical trials methodology. In many ways, the themes that emerged were not wholly dissimilar from the general preferences of members of other sociolinguistic minority groups-a need for communication access, empathy, respect, strict confidentiality procedures, trust, and transparency of the research process. Yet, how these themes are applied to the inclusion of Deaf research participants is distinct from any other sociolinguistic minority population, given Deaf people's unique sensory and linguistic characteristics. We summarize our findings in a preliminary "Checklist for Designing Deaf Behavioral Clinical Trials" to operationalize the steps researchers can take to apply Deaf-friendly approaches in their empirical work. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Self-Injury, Help-Seeking, and the Internet: Informing Online Service Provision for Young People.

PubMed

Frost, Mareka; Casey, Leanne; Rando, Natalie

2016-01-01

Although increasing numbers of young people are seeking help online for self-injury, relatively little is known about their online help-seeking preferences. To investigate the perspectives of young people who self-injure regarding online services, with the aim of informing online service delivery. A mixed-methods exploratory analysis regarding the perspectives of a subsample of young people who reported a history of self-injury and responded to questions regarding preferences for future online help-seeking (N = 457). The sample was identified as part of a larger study (N = 1,463) exploring self-injury and help-seeking. Seven themes emerged in relation to preferences for future online help-seeking: information, guidance, reduced isolation, online culture, facilitation of help-seeking, access, and privacy. Direct contact with a professional via instant messaging was the most highly endorsed form of online support. Young people expressed clear preferences regarding online services for self-injury, supporting the importance of consumer consultation in development of online services.

Primordial non-Gaussianity and reionization

NASA Astrophysics Data System (ADS)

Lidz, Adam; Baxter, Eric J.; Adshead, Peter; Dodelson, Scott

2013-07-01

The statistical properties of the primordial perturbations contain clues about their origins. Although the Planck collaboration has recently obtained tight constraints on primordial non-Gaussianity from cosmic microwave background measurements, it is still worthwhile to mine upcoming data sets in an effort to place independent or competitive limits. The ionized bubbles that formed at redshift z˜6-20 during the epoch of reionization were seeded by primordial overdensities, and so the statistics of the ionization field at high redshift are related to the statistics of the primordial field. Here we model the effect of primordial non-Gaussianity on the reionization field. The epoch and duration of reionization are affected, as are the sizes of the ionized bubbles, but these changes are degenerate with variations in the properties of the ionizing sources and the surrounding intergalactic medium. A more promising signature is the power spectrum of the spatial fluctuations in the ionization field, which may be probed by upcoming 21 cm surveys. This has the expected 1/k2 dependence on large scales, characteristic of a biased tracer of the matter field. We project how well upcoming 21 cm observations will be able to disentangle this signal from foreground contamination. Although foreground cleaning inevitably removes the large-scale modes most impacted by primordial non-Gaussianity, we find that primordial non-Gaussianity can be separated from foreground contamination for a narrow range of length scales. In principle, futuristic redshifted 21 cm surveys may allow constraints competitive with Planck.

Constraining local reionization histories with 21 cm observations

NASA Astrophysics Data System (ADS)

Beardsley, Adam

2018-01-01

Several low-frequency radio instruments are poised to detect faint signatures of the Epoch of Reionization through the redshifted HI 21 cm line, while near-infrared (NIR) observations continue to push studies of galactic properties to higher redshifts. With ongoing upgrades to radio facilities and the imminent launch of JWST, both fields are on the verge of revolutionary advances in the characterization of the EoR. But there remains an open question of how to marry these observations in a way that will fully exploit their complementary nature. NIR observations will reveal how galaxies formed and evolved, while 21 cm observations will trace the impact early galaxies had on their large scale environments. Simultaneous observation of these two physical processes is difficult owing to the disparate scales probed by the instruments. I will present a method for using images of large-scale 21 cm brightness temperature to constrain the reionization history of a given region of cosmological volume, thereby providing environmental context to galaxy observations in the same region. This framework is complicated by foreground contamination in 21 cm EoR images, but can be mitigated with filtering techniques and useful information is still recoverable. By adding local reionization history to NIR surveys, we will be able to distinguish between galaxies in a variety of environments. This has the potential to enhance expected signatures such as the flattening of the luminosity function at high redshift, or reveal new observables altogether.

Reionization in sterile neutrino cosmologies

NASA Astrophysics Data System (ADS)

Bose, Sownak; Frenk, Carlos S.; Hou, Jun; Lacey, Cedric G.; Lovell, Mark R.

2016-12-01

We investigate the process of reionization in a model in which the dark matter is a warm elementary particle such as a sterile neutrino. We focus on models that are consistent with the dark matter decay interpretation of the recently detected line at 3.5 keV in the X-ray spectra of galaxies and clusters. In warm dark matter models, the primordial spectrum of density perturbations has a cut-off on the scale of dwarf galaxies. Structure formation therefore begins later than in the standard cold dark matter (CDM) model and very few objects form below the cut-off mass scale. To calculate the number of ionizing photons, we use the Durham semi-analytic model of galaxy formation, GALFORM. We find that even the most extreme 7 keV sterile neutrino we consider is able to reionize the Universe early enough to be compatible with the bounds on the epoch of reionization from Planck. This, perhaps surprising, result arises from the rapid build-up of high redshift galaxies in the sterile neutrino models which is also reflected in a faster evolution of their far-UV luminosity function between 10 > z > 7 than in CDM. The dominant sources of ionizing photons are systematically more massive in the sterile neutrino models than in CDM. As a consistency check on the models, we calculate the present-day luminosity function of satellites of Milky Way-like galaxies. When the satellites recently discovered in the Dark Energy Survey are taken into account, strong constraints are placed on viable sterile neutrino models.

Through the Looking GLASS: A JWST Exploration of Galaxy Formation and Evolution from Cosmic Dawn to Present Day

NASA Astrophysics Data System (ADS)

Treu, Tommaso; Abramson, L.; Bradac, M.; Brammer, G.; Fontana, A.; Henry, A.; Hoag, A.; Huang, K.; Mason, C.; Morishita, T.; Pentericci, L.; Wang, X.

2017-11-01

We propose a carefully designed set of observations of the lensing cluster Abell 2744 to study intrinsically faint magnified galaxies from the epoch of reionization to redshift of 1, demonstrating and characterizing complementary spectroscopic modes with NIRSPEC and NIRISS. The observations are designed to address the questions: 1) when did reionization happen and what were the sources of reionizing photons? 2) How do baryons cycle in and out of galaxies? This dataset with deep spectroscopy on the cluster and deep multiband NIRCAM imaging in parallel will enable a wealth of investigations and will thus be of interest to a broad section of the astronomical community. The dataset will illustrate the power and challenges of: 1) combining rest frame UV and optical NIRSPEC spectroscopy for galaxies at the epoch of reionization, 2) obtaining spatially resolved emission line maps with NIRISS, 3) combining NIRISS and NIRSPEC spectroscopy. Building on our extensive experience with HST slitless spectroscopy and imaging in clusters of galaxies as part of the GLASS, WISP, SURFSUP, and ASTRODEEP projects, we will provide the following science-enabling products to the community: 1)quantitative comparison of spatially resolved (NIRISS) and spectrally resolved (NIRSPEC) spectroscopy, 2) Object based interactive exploration tools for multi-instrument datasets, 3) Interface for easy forced extractionof slitless spectra based on coordinates, 4) UV-optical spectroscopic templates of highredshift galaxies, 5) NIRCAM parallel catalogs and a list of 26 z>=9 dropouts for spectroscopic follow-up in Cycle-2.

Is there another coincidence problem at the reionization epoch?

NASA Astrophysics Data System (ADS)

Lombriser, Lucas; Smer-Barreto, Vanessa

2017-12-01

The cosmological coincidences between the matter and radiation energy densities at recombination as well as between the densities of matter and the cosmological constant at the present time are well known. We point out that, moreover, the third intersection between the energy densities of radiation and the cosmological constant coincides with the reionization epoch. To quantify the statistical relevance of this concurrence, we compute the Bayes factor between the concordance cosmology with free Thomson scattering optical depth and a model for which this parameter is inferred from imposing a match between the time of density equality and the epoch of reionization. This is to characterize the potential explanatory gain if one were to find a parameter-free physical connection. We find a very strong preference for such a concurrence on the Jeffreys scale from current cosmological observations. We furthermore discuss the effect of the choice of priors, changes in reionization history, and free sum of neutrino masses. We also estimate the impact of adding intermediate polarization data from the Planck High Frequency Instrument and prospects for future 21 cm surveys. In the first case, the preference for the correlation remains substantial, whereas future data may give results more decisive in pro or substantial in contra of it. Finally, we provide a discussion on different interpretations of these findings. In particular, we show how a connection between the star-formation history and the cosmological background dynamics can give rise to this concurrence.

"Why do you want your child to have braces?" Investigating the motivations of Hispanic/Latino and white parents.

PubMed

Davis, Blake B; Bayirli, Burcu; Ramsay, Douglas S; Turpin, David L; Paige, Andrew; Riedy, Christine A

2015-11-01

Many psychological, social, and cultural factors influence parents' motivation to seek orthodontic care for their children. In this study, we used Q methodology to identify and categorize shared motives and determine whether cultural differences exist between Hispanic/Latino (H/L) and non-Hispanic/Latino, white (W) parents. The fundamental question posed to the parents was "Why do you want your child to have braces?" Q methodology involves 3 stages. (1) Interviews of H/L (n = 5) and W (n = 5) parents generated 35 statements that represented different motives to seek orthodontic care. (2) In the Q sort, 70 new parents (22 H/L, 48 W) ranked statements in order of relative importance using a forced distribution grid. (3) Factor analysis was performed separately for the H/L and W groups to uncover cultural differences. Four motivational profiles were described for both the H/L and W parents based on the significant factors identified in each group. More H/L parents (18 of 22 parents) than W parents (22 of 48 parents) were characterized by 1 of their group's 4 profiles. Comparisons of the motivational profiles across the groups showed 4 global themes: well-timed treatment that prevents future dental problems, parental responsibility, perceived benefits, and perceived need instilled by the dentist. Four global themes captured the motives of most parents seeking orthodontic treatment for their children. Understanding these global themes can help clinicians frame their treatment discussions with parents. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Ethnic Differences for Public Health Knowledge, Health Advocacy Skills, and Health Information Seeking Among High School Students: Community Agents of Change.

PubMed

Kratzke, Cynthia; Rao, Satya; Marquez, Ruben

2018-03-06

Although adult health advocacy programs have been examined in communities, little is known about integrated adolescent health advocacy programs in high schools. The purpose of this study was to examine the health advocacy program impact and ethnic differences among high school students. Using a cross-sectional study, high school students participating in the school-based program completed evaluation surveys. The program domains included upstream causes of health, community assets, and public health advocacy. Bivariate analyses were conducted to examine ethnic differences for public health knowledge, health advocacy skills, and health information seeking behaviors. Using thematic analysis, open-ended survey item responses were coded to identify themes for students' perceptions of community health. Non-Hispanic (n = 72) and Hispanic high school students (n = 182) in ten classes reported owning smartphones (95%) and laptops (76%). Most students (72%) reported seeking online health information. Non-Hispanic students reported significantly higher health advocacy skills for speaking with the class about health issues, identifying community services, or creating health awareness at school than Hispanic students. Non-Hispanic students were more likely to seek health information from fathers and television than Hispanic students. Hispanic students were more likely to seek health information from hospital or clinic staff than non-Hispanic students. Emergent themes included health advocacy skills, community awareness, and individual and community health changes. High schools benefit from integrating health advocacy programs into the core curriculum. Adolescents gain important skills to improve their individual health and engage in changing community health.

Cosmology and Astrophysics using the Post-Reionization HI

NASA Astrophysics Data System (ADS)

Sarkar, Tapomoy Guha; Sen, Anjan A.

2016-12-01

We discuss the prospects of using the redshifted 21-cm emission from neutral hydrogen in the post-reionization epoch to study our Universe. The main aim of the article is to highlight the efforts of Indian scientists in this area with the SKA in mind. It turns out that the intensity mapping surveys from SKA can be instrumental in obtaining tighter constraints on the dark energy models. Cross-correlation of the HI intensity maps with the Ly α forest data can also be useful in measuring the BAO scale.

The experience of initiating injection drug use and its social context: a qualitative systematic review and thematic synthesis.

PubMed

Guise, Andy; Horyniak, Danielle; Melo, Jason; McNeil, Ryan; Werb, Dan

2017-12-01

Understanding the experience of initiating injection drug use and its social contexts is crucial to inform efforts to prevent transitions into this mode of drug consumption and support harm reduction. We reviewed and synthesized existing qualitative scientific literature systematically to identify the socio-structural contexts for, and experiences of, the initiation of injection drug use. We searched six databases (Medline, Embase, PsychINFO, CINAHL, IBSS and SSCI) systematically, along with a manual search, including key journals and subject experts. Peer-reviewed studies were included if they qualitatively explored experiences of or socio-structural contexts for injection drug use initiation. A thematic synthesis approach was used to identify descriptive and analytical themes throughout studies. From 1731 initial results, 41 studies reporting data from 1996 participants were included. We developed eight descriptive themes and two analytical (higher-order) themes. The first analytical theme focused on injecting initiation resulting from a social process enabled and constrained by socio-structural factors: social networks and individual interactions, socialization into drug-using identities and choices enabled and constrained by social context all combine to produce processes of injection initiation. The second analytical theme addressed pathways that explore varying meanings attached to injection initiation and how they link to social context: seeking pleasure, responses to increasing tolerance to drugs, securing belonging and identity and coping with pain and trauma. Qualitative research shows that injection drug use initiation has varying and distinct meanings for individuals involved and is a dynamic process shaped by social and structural factors. Interventions should therefore respond to the socio-structural influences on injecting drug use initiation by seeking to modify the contexts for initiation, rather than solely prioritizing the reduction of individual harms through behavior change. © 2017 Society for the Study of Addiction.

Evidence based practice in traditional & complementary medicine: An agenda for policy, practice, education and research.

PubMed

Leach, Matthew J; Canaway, Rachel; Hunter, Jennifer

2018-05-01

To develop a policy, practice, education and research agenda for evidence-based practice (EBP) in traditional and complementary medicine (T&CM). The study was a secondary analysis of qualitative data, using the method of roundtable discussion. The sample comprised seventeen experts in EBP and T&CM. The discussion was audio-recorded, and the transcript analysed using thematic analysis. Four central themes emerged from the data; understanding evidence and EBP, drivers of change, interpersonal interaction, and moving forward. Captured within these themes were fifteen sub-themes. These themes/sub-themes translated into three broad calls to action: (1) defining terminology, (2) defining the EBP approach, and (3) fostering social movement. These calls to action formed the framework of the agenda. This analysis presents a potential framework for an agenda to improve EBP implementation in T&CM. The fundamental elements of this action plan seek clarification, leadership and unification on the issue of EBP in T&CM. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biobased Organic Chemistry Laboratories as Sustainable Experiment Alternatives

ERIC Educational Resources Information Center

Silverman, Julian R.

2016-01-01

As nonrenewable resources deplete and educators seek relevant interdisciplinary content for organic chemistry instruction, biobased laboratory experiments present themselves as potential alternatives to petroleum-based transformations, which offer themselves as sustainable variations on important themes. Following the principles of green chemistry…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, Daniel C.; Bowman, Judd; Parsons, Aaron R.

We present a catalog of spectral measurements covering a 100-200 MHz band for 32 sources, derived from observations with a 64 antenna deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in South Africa. For transit telescopes such as PAPER, calibration of the primary beam is a difficult endeavor and errors in this calibration are a major source of error in the determination of source spectra. In order to decrease our reliance on an accurate beam calibration, we focus on calibrating sources in a narrow declination range from –46° to –40°. Since sources atmore » similar declinations follow nearly identical paths through the primary beam, this restriction greatly reduces errors associated with beam calibration, yielding a dramatic improvement in the accuracy of derived source spectra. Extrapolating from higher frequency catalogs, we derive the flux scale using a Monte Carlo fit across multiple sources that includes uncertainty from both catalog and measurement errors. Fitting spectral models to catalog data and these new PAPER measurements, we derive new flux models for Pictor A and 31 other sources at nearby declinations; 90% are found to confirm and refine a power-law model for flux density. Of particular importance is the new Pictor A flux model, which is accurate to 1.4% and shows that between 100 MHz and 2 GHz, in contrast with previous models, the spectrum of Pictor A is consistent with a single power law given by a flux at 150 MHz of 382 ± 5.4 Jy and a spectral index of –0.76 ± 0.01. This accuracy represents an order of magnitude improvement over previous measurements in this band and is limited by the uncertainty in the catalog measurements used to estimate the absolute flux scale. The simplicity and improved accuracy of Pictor A's spectrum make it an excellent calibrator in a band important for experiments seeking to measure 21 cm emission from the epoch of reionization.« less

No evidence for a significant AGN contribution to cosmic hydrogen reionization

NASA Astrophysics Data System (ADS)

Parsa, Shaghayegh; Dunlop, James S.; McLure, Ross J.

2018-03-01

We reinvestigate a claimed sample of 22 X-ray detected active galactic nuclei (AGN) at redshifts z > 4, which has reignited the debate as to whether young galaxies or AGN reionized the Universe. These sources lie within the Great Observatories Origins Deep Survey-South (GOODS-S)/Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) field, and we examine both the robustness of the claimed X-ray detections (within the Chandra 4Ms imaging) and perform an independent analysis of the photometric redshifts of the optical/infrared counterparts. We confirm the reality of only 15 of the 22 reported X-ray detections, and moreover find that only 12 of the 22 optical/infrared counterpart galaxies actually lie robustly at z > 4. Combining these results we find convincing evidence for only seven X-ray AGN at z > 4 in the GOODS-S field, of which only one lies at z > 5. We recalculate the evolving far-ultraviolet (1500 Å) luminosity density produced by AGN at high redshift, and find that it declines rapidly from z ≃ 4 to z ≃ 6, in agreement with several other recent studies of the evolving AGN luminosity function. The associated rapid decline in inferred hydrogen ionizing emissivity contributed by AGN falls an order-of-magnitude short of the level required to maintain hydrogen ionization at z ≃ 6. We conclude that all available evidence continues to favour a scenario in which young galaxies reionized the Universe, with AGN making, at most, a very minor contribution to cosmic hydrogen reionization.

The globular cluster-dark matter halo connection

NASA Astrophysics Data System (ADS)

Boylan-Kolchin, Michael

2017-12-01

I present a simple phenomenological model for the observed linear scaling of the stellar mass in old globular clusters (GCs) with z = 0 halo mass in which the stellar mass in GCs scales linearly with progenitor halo mass at z = 6 above a minimum halo mass for GC formation. This model reproduces the observed MGCs-Mhalo relation at z = 0 and results in a prediction for the minimum halo mass at z = 6 required for hosting one GC: Mmin(z = 6) = 1.07 × 109 M⊙. Translated to z = 0, the mean threshold mass is Mhalo(z = 0) ≈ 2 × 1010 M⊙. I explore the observability of GCs in the reionization era and their contribution to cosmic reionization, both of which depend sensitively on the (unknown) ratio of GC birth mass to present-day stellar mass, ξ. Based on current detections of z ≳ 6 objects with M1500<-17, values of ξ > 10 are strongly disfavoured; this, in turn, has potentially important implications for GC formation scenarios. Even for low values of ξ, some observed high-z galaxies may actually be GCs, complicating estimates of reionization-era galaxy ultraviolet luminosity functions and constraints on dark matter models. GCs are likely important reionization sources if 5 ≲ ξ ≲ 10. I also explore predictions for the fraction of accreted versus in situ GCs in the local Universe and for descendants of systems at the halo mass threshold of GC formation (dwarf galaxies). An appealing feature of the model presented here is the ability to make predictions for GC properties based solely on dark matter halo merger trees.

Dark-ages reionization and galaxy formation simulation - X. The small contribution of quasars to reionization

NASA Astrophysics Data System (ADS)

Qin, Yuxiang; Mutch, Simon J.; Poole, Gregory B.; Liu, Chuanwu; Angel, Paul W.; Duffy, Alan R.; Geil, Paul M.; Mesinger, Andrei; Wyithe, J. Stuart B.

2017-12-01

Motivated by recent measurements of the number density of faint AGN at high redshift, we investigate the contribution of quasars to reionization by tracking the growth of central supermassive black holes in an update of the MERAXES semi-analytic model. The model is calibrated against the observed stellar mass function at z ∼ 0.6-7, the black hole mass function at z ≲ 0.5, the global ionizing emissivity at z ∼ 2-5 and the Thomson scattering optical depth. The model reproduces a Magorrian relation in agreement with observations at z < 0.5 and predicts a decreasing black hole mass towards higher redshifts at fixed total stellar mass. With the implementation of an opening angle of 80 deg for quasar radiation, corresponding to an observable fraction of ∼23.4 per cent due to obscuration by dust, the model is able to reproduce the observed quasar luminosity function at z ∼ 0.6-6. The stellar light from galaxies hosting faint active galactic nucleus (AGN) contributes a significant or dominant fraction of the UV flux. At high redshift, the model is consistent with the bright end quasar luminosity function and suggests that the recent faint z ∼ 4 AGN sample compiled by Giallongo et al. (2015) includes a significant fraction of stellar light. Direct application of this luminosity function to the calculation of AGN ionizing emissivity consequently overestimates the number of ionizing photons produced by quasars by a factor of 3 at z ∼ 6. We conclude that quasars are unlikely to make a significant contribution to reionization.

The Hydrogen Epoch of Reionization Array Dish. II. Characterization of Spectral Structure with Electromagnetic Simulations and Its Science Implications.

NASA Astrophysics Data System (ADS)

Ewall-Wice, Aaron; Bradley, Richard; Deboer, David; Hewitt, Jacqueline; Parsons, Aaron; Aguirre, James; Ali, Zaki S.; Bowman, Judd; Cheng, Carina; Neben, Abraham R.; Patra, Nipanjana; Thyagarajan, Nithyanandan; Venter, Mariet; de Lera Acedo, Eloy; Dillon, Joshua S.; Dickenson, Roger; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Klima, Patricia; Kohn, Saul; Schaffner, Patrick; Shelton, John; Saliwanchik, Benjamin; Taylor, H. A.; Taylor, Rusty; Tegmark, Max; Wirt, Butch

2016-11-01

We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish’s design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA’s suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA’s ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effective for increasing the sensitivity of EoR experiments at a relatively low cost. We find that electromagnetic resonances in the HERA feed’s cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below k ∥ ≲ 0.2 h Mpc-1, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.

The Universe Is Reionizing at z ∼ 7: Bayesian Inference of the IGM Neutral Fraction Using Lyα Emission from Galaxies

NASA Astrophysics Data System (ADS)

Mason, Charlotte A.; Treu, Tommaso; Dijkstra, Mark; Mesinger, Andrei; Trenti, Michele; Pentericci, Laura; de Barros, Stephane; Vanzella, Eros

2018-03-01

We present a new flexible Bayesian framework for directly inferring the fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch of Reionization (EoR, z ∼ 6–10) from detections and non-detections of Lyman Alpha (Lyα) emission from Lyman Break galaxies (LBGs). Our framework combines sophisticated reionization simulations with empirical models of the interstellar medium (ISM) radiative transfer effects on Lyα. We assert that the Lyα line profile emerging from the ISM has an important impact on the resulting transmission of photons through the IGM, and that these line profiles depend on galaxy properties. We model this effect by considering the peak velocity offset of Lyα lines from host galaxies’ systemic redshifts, which are empirically correlated with UV luminosity and redshift (or halo mass at fixed redshift). We use our framework on the sample of LBGs presented in Pentericci et al. and infer a global neutral fraction at z ∼ 7 of {\\overline{x}}{{H}{{I}}}={0.59}-0.15+0.11, consistent with other robust probes of the EoR and confirming that reionization is ongoing ∼700 Myr after the Big Bang. We show that using the full distribution of Lyα equivalent width detections and upper limits from LBGs places tighter constraints on the evolving IGM than the standard Lyα emitter fraction, and that larger samples are within reach of deep spectroscopic surveys of gravitationally lensed fields and James Webb Space Telescope NIRSpec.

Constraining SN feedback: a tug of war between reionization and the Milky Way satellites

NASA Astrophysics Data System (ADS)

Hou, Jun; Frenk, Carlos. S.; Lacey, Cedric G.; Bose, Sownak

2016-12-01

Theoretical models of galaxy formation based on the cold dark matter cosmogony typically require strong feedback from supernova (SN) explosions in order to reproduce the Milky Way satellite galaxy luminosity function and the faint end of the field galaxy luminosity function. However, too strong a SN feedback also leads to the universe reionizing too late, and the metallicities of Milky Way satellites being too low. The combination of these four observations therefore places tight constraints on SN feedback. We investigate these constraints using the semi-analytical galaxy formation model GALFORM. We find that these observations favour a SN feedback model in which the feedback strength evolves with redshift. We find that, for our best-fitting model, half of the ionizing photons are emitted by galaxies with rest-frame far-UV absolute magnitudes MAB(1500Å) < -17.5, which implies that already observed galaxy populations contribute about half of the photons responsible for reionization. The z = 0 descendants of these galaxies are mainly galaxies with stellar mass M* > 1010 M⊙ and preferentially inhabit haloes with mass Mhalo > 1013 M⊙.

Studying Cosmic Dawn with WFIRST

NASA Astrophysics Data System (ADS)

Rhoads, James; Malhotra, Sangeeta; Jansen, Rolf A.; Windhorst, Rogier; Tilvi, Vithal; Finkelstein, Steven; Wold, Isak; Papovich, Casey; Fan, Xiaohui; Mellema, Garrelt; Zackrisson, Erik; Jensen, Hannes; T

2018-01-01

Our understanding of Cosmic Dawn can be revolutionized using WFIRST's combination of wide-field, sensitive, high resolution near-infrared imaging and spectroscopy. Guest investigator studies of WFIRST's high latitude imaging survey and supernova search fields will yield orders of magnitude increases in our samples of Lyman break galaxies from z=7 to z>12. The high latitude spectrsocopic survey will enable an unprecedented search for z>7 quasars. Guest observer deep fields can extend these studies to flux levels of Hubble's deepest fields, over regions measured in square degrees. The resulting census of luminous objects in the Cosmic Dawn will provide key insights into the sources of the ultraviolet photons that powered reionization. Moreover, because WFIRST has a wide field (slitless) spectroscopic capability, it can be used to search for Lyman alpha emitting galaxies over the full history of reionization. By comparing the Lyman alpha galaxy statistics to those of continuum sources, we can directly probe the transparency of the intergalactic gas and chart reionization history.Our team is planning for both Guest Investigator and Guest Observer applications of WFIRST to studying Cosmic Dawn, and welcomes dialog with other interested members of the community.

A Search for z>6.5 Lyman-alpha Emitting Galaxies with WISP

NASA Astrophysics Data System (ADS)

Bagley, Micaela B.; Scarlata, Claudia; Dai, Yu Sophia; Rafelski, Marc; Baronchelli, Ivano; Colbert, James W.; Dominguez, Alberto; Hathi, Nimish P.; Henry, Alaina L.; Malkan, Matthew Arnold; Martin, Crystal L.; Mehta, Vihang; Pahl, Anthony; Ross, Nathaniel; Rutkowski, Michael J.; Teplitz, Harry I.; WISP Team

2016-01-01

The observed number density of Lyman-alpha emitting galaxies at z>6 provides an important probe of the reionization history of the universe. Because Lyman-alpha photons are very sensitive to the presence of neutral hydrogen, the evolution of the galaxy number density above redshift 6 can be used as a measurement on the progress of reionization. However, the Lyman-alpha luminosity function is currently poorly constrained at high-z. We present the results of a systematic search for Lyman-alpha emitters (LAEs) at redshifts of ~6.5 to 7.5 using the HST WFC3 Infrared Spectroscopic Parallels (WISP) survey. WISP's uncorrelated fields are well-suited to the study of bright LAEs, minimizing the effects of clustering introduced by a patchy reionization. From the 30 deepest WISP fields, we compile a sample of single-line emitters, confirm redshifts with broadband colors, and identify LAE candidates that have "dropped out" (are undetected at the 1 sigma level) of the WFC3 UVIS filters. By combining our results with other z~7 studies, we determine whether the number density of LAEs evolves past z~6.5.

Impact of Sommerfeld enhancement on helium reionization via WIMP dark matter

NASA Astrophysics Data System (ADS)

Bandyopadhyay, Bidisha; Schleicher, Dominik R. G.

2018-03-01

Dark matter annihilation can have a strong impact on many astrophysical processes in the Universe. In the case of Sommerfeld-enhanced annihilation cross sections, the annihilation rates are enhanced at late times, thus enhancing the potential annihilation signatures. We here calculate the Sommerfeld-enhanced annihilation signatures during the epoch of helium reionization, the epoch where helium becomes fully ionized due to energetic photons. When considering the upper limits on the energy injection from the CMB, we find that the resulting abundance of He++ becomes independent of the dark matter particle mass. The resulting enhancement compared to a standard scenario is thus 1-2 orders of magnitude higher. For realistic scenarios compatible with CMB constraints, there is no significant shift in the epoch of helium reionization, which is completed between redshifts 3 and 4. While it is thus difficult to disentangle dark matter annihilation from astrophysical contributions (active galactic nuclei), a potential detection of dark matter particles and its interactions using the Large Hadron Collider (LHC) would allow one to quantify the dark matter contribution.

PAPER: The Precision Array To Probe The Epoch Of Reionization

NASA Astrophysics Data System (ADS)

Backer, Donald C.; Parsons, A.; Bradley, R.; Parashare, C.; Gugliucci, N.; Mastrantonio, E.; Herne, D.; Lynch, M.; Wright, M.; Werhimer, D.; Carilli, C.; Datta, A.; Aguirre, J.

2007-12-01

The Precision Array to Probe the Epoch of Reionization (PAPER) is an experiment that is being designed to detect the faint HI signal from the epoch of reionization. Our instrumentation goals include: the design and building of dipole elements that are optimized for operation from 120-190 MHz with a clean beam response; amplifiers and receivers with good impedance match and overall flat gain response over a large bandpass; and an FPGA correlator capable of producing full Stokes products for the array. The array is being built and evaluated in stages at the Green Bank Observatory in West Virginia with deployment of the full instrument in Western Australia. We present results from an eight-station deployment in Green Bank and four-station deployment in Western Australia, including phase and amplitude calibration, RFI mitigation and removal, full sky maps, and wide-field snapshot imaging. We have discovered new ways to improve our system's stability and sensitivity from these early experiments, and are applying these concepts to a 16-element array in Green Bank in early 2008 and a 32-element array in Western Australia later in 2008.

Cosmic Reionization On Computers: Numerical and Physical Convergence

DOE PAGES

Gnedin, Nickolay Y.

2016-04-01

In this paper I show that simulations of reionization performed under the Cosmic Reionization On Computers (CROC) project do converge in space and mass, albeit rather slowly. A fully converged solution (for a given star formation and feedback model) can be determined at a level of precision of about 20%, but such a solution is useless in practice, since achieving it in production-grade simulations would require a large set of runs at various mass and spatial resolutions, and computational resources for such an undertaking are not yet readily available. In order to make progress in the interim, I introduce amore » weak convergence correction factor in the star formation recipe, which allows one to approximate the fully converged solution with finite resolution simulations. The accuracy of weakly converged simulations approaches a comparable, ~20% level of precision for star formation histories of individual galactic halos and other galactic properties that are directly related to star formation rates, like stellar masses and metallicities. Yet other properties of model galaxies, for example, their HI masses, are recovered in the weakly converged runs only within a factor of two.« less

RELICS: Reionization Lensing Cluster Survey

NASA Astrophysics Data System (ADS)

Coe, Dan A.; RELICS Team

2017-01-01

Hubble and Spitzer imaging programs observing galaxy cluster lenses have delivered some of the highest redshift galaxy candidates to date (z ~ 9 - 11, or 540 - 410 Myr after the Big Bang). These magnified galaxies are intrinsically faint, and thus more representative of the sources believed to be primarily responsible for reionization. Magnified galaxies are also observed brightly enough to be prime targets for detailed follow-up study with current and future observatories, including JWST. Building on the successes of CLASH and the Frontier Fields, we have begun RELICS, the Reionization Lensing Cluster Survey. By observing 41 massive clusters for the first time at infrared wavelengths, RELICS will deliver more of the best and brightest high-redshift candidates to the community in time for the November 2017 JWST GO Cycle 1 call for proposals. I will present our early results. I will also discuss prospects for JWST to follow-up known candidates and discover new galaxies at even higher redshifts (z > 11). The discovery efficiency gains from lensing will be even more pronounced at z > 11 if luminosity function faint end slopes are steeper than alpha ~ -2, as suggested by current models and observational extrapolations.

Cosmic Reionization On Computers: Numerical and Physical Convergence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.

In this paper I show that simulations of reionization performed under the Cosmic Reionization On Computers (CROC) project do converge in space and mass, albeit rather slowly. A fully converged solution (for a given star formation and feedback model) can be determined at a level of precision of about 20%, but such a solution is useless in practice, since achieving it in production-grade simulations would require a large set of runs at various mass and spatial resolutions, and computational resources for such an undertaking are not yet readily available. In order to make progress in the interim, I introduce amore » weak convergence correction factor in the star formation recipe, which allows one to approximate the fully converged solution with finite resolution simulations. The accuracy of weakly converged simulations approaches a comparable, ~20% level of precision for star formation histories of individual galactic halos and other galactic properties that are directly related to star formation rates, like stellar masses and metallicities. Yet other properties of model galaxies, for example, their HI masses, are recovered in the weakly converged runs only within a factor of two.« less

Reionization and the cosmic microwave background in an open universe

NASA Technical Reports Server (NTRS)

Persi, Fred M.

1995-01-01

If the universe was reionized at high reshift (z greater than or approximately equal to 30) or never recombined, then photon-electron scattering can erase fluctuations in the cosmic microwave background at scales less than or approximately equal to 1 deg. Peculiar motion at the surface of last scattering will then have given rise to new anisotropy at the 1 min level through the Vishniac effect. Here the observed fluctuations in galaxy counts are extrapolated to high redshifts using linear theory, and the expected anisotropy is computed. The predicted level of anisotropies is a function of Omega(sub 0) and the ratio of the density in ionized baryons to the critical density and is shown to depend strongly on the large- and small-scale power. It is not possible to make general statements about the viability of all reionized models based on current observations, but it is possible to rule out specific models for structure formation, particularly those with high baryonic content or small-scale power. The induced fluctuations are shown to scale with cosmological parameters and optical depth.

Experiences of Nigerian Internationally Educated Nurses Transitioning to United States Health Care Settings.

PubMed

Iheduru-Anderson, Kechinyere C; Wahi, Monika M

2018-04-01

Successful transition to practice of internationally educated nurses (IENs) can critically affect quality of care. The aim of this study was to characterize the facilitators and barriers to transition of Nigerian IENs (NIENs) to the United States health care setting. Using a descriptive phenomenology approach, 6 NIENs were interviewed about their transitional experiences in the United States. Thematic methods were used for data analysis. The three major themes identified from the participants' stories were "fear/anger and disappointment" (FAD), "road/journey to success/overcoming challenges" (RJO), and "moving forward" (MF). The FAD theme predominated, including experiences of racism, bullying, and inequality. The RJO theme included resilience, and the MF theme encompassed personal growth. NIENs face personal and organizational barriers to adaptation, especially fear, anger and disappointment. Future research should seek to develop a model for optimal adaptation that focuses on improving both personal and organizational facilitators and decreasing barriers.

The Experience of Women Veterans Coming Back from War.

PubMed

Maiocco, Gina; Smith, Mary Jane

2016-06-01

Issues surrounding mental health are common for women veterans who have served in Iraq and Afghanistan wars. The goal of this phenomenological study was to document themes in the stories gathered from eight women veterans who had come back from war. Themes in the stories were: arriving with mixed sentiments; evolving to a changed view of self; permeating aggravation; confounding broken relationships, frequent deployments, and change in military status; remembering war experiences; and seeking opportunity for what is possible. Mental health issues can be observed in the themes. Including story as part of the mental health visit with veterans may be beneficial to veterans as they deal with the transition of coming back. Copyright © 2016 Elsevier Inc. All rights reserved.

Math and Science. IDRA Focus.

ERIC Educational Resources Information Center

IDRA Newsletter, 1995

1995-01-01

This theme issue contains six articles on improving math and science education for minority group students, particularly language-minority students. "Accelerating Content Area Gains for English Language Learners" (Laura Chris Green) describes the Young Scientists Acquiring English project, which seeks to improve the content-area…

Counseling Taiwan Chinese in America: Training Issues for Counselors.

ERIC Educational Resources Information Center

Miller, Geri; Yang, Julia; Chen, M.

1997-01-01

Examines cultural influences (such as Confucianism, family, and immigration) on Taiwan Chinese in America who seek counseling. Addresses typical counseling struggles, effective counseling strategies and theoretical approaches, and training implications. Uses a case study to elaborate on the above themes. (RJM)

Personal experiences of people with serious mental illness when seeking, obtaining and maintaining competitive employment in Queensland, Australia.

PubMed

Gladman, Beverley; Waghorn, Geoff

2016-02-15

High non-participation in the labour force and unemployment remain challenging for adults with serious mental illness. This study examined the personal experiences of people with serious mental illness when seeking, obtaining and maintaining competitive employment. The aim was to increase understanding of personal experiences of employment and how these experiences can be used to inform the assistance provided in support of clients' competitive employment goals. Qualitative data from a two-year period were thematically analysed from one participating site in a multi-site trial of employment services integrated with public funded community mental health treatment and care. Both positive and negative themes arose. Positive themes included: Aspirations for a better life, receiving feedback on good job performance, employment displacing preoccupation with illness, and employment improving self-esteem and reducing financial stress. Negative themes included stigma experiences, stress, and health difficulties. Both positive and negative experiences did not depend on type of employment service assistance nor key client characteristics such as age, sex, and diagnostic category. Despite its many benefits, employment can also increase the risk of negative personal experiences. These findings suggest that employment service providers could do more to assist people who commence employment, to reduce the risk of negative personal experiences and to enhance the benefits of competitive employment.

Clusters of primordial black holes and reionization problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belotsky, K. M., E-mail: k-belotsky@yandex.ru; Kirillov, A. A., E-mail: kirillov-aa@yandex.ru; Rubin, S. G., E-mail: sergeirubin@list.ru

2015-05-15

Clusters of primordial black holes may cause the formation of quasars in the early Universe. In turn, radiation from these quasars may lead to the reionization of the Universe. However, the evaporation of primordial black holes via Hawking’s mechanism may also contribute to the ionization of matter. The possibility of matter ionization via the evaporation of primordial black holes with allowance for existing constraints on their density is discussed. The contribution to ionization from the evaporation of primordial black holes characterized by their preset mass spectrum can roughly be estimated at about 10{sup −3}.

21-cm lensing and the cold spot in the cosmic microwave background.

PubMed

Kovetz, Ely D; Kamionkowski, Marc

2013-04-26

An extremely large void and a cosmic texture are two possible explanations for the cold spot seen in the cosmic microwave background. We investigate how well these two hypotheses can be tested with weak lensing of 21-cm fluctuations from the epoch of reionization measured with the Square Kilometer Array. While the void explanation for the cold spot can be tested with Square Kilometer Array, given enough observation time, the texture scenario requires significantly prolonged observations, at the highest frequencies that correspond to the epoch of reionization, over the field of view containing the cold spot.

Powerful Literacies.

ERIC Educational Resources Information Center

Crowther, Jim, Ed.; Hamilton, Mary, Ed.; Tett, Lyn, Ed.

These 15 papers share a common theme: seeking to promote literacy as a powerful tool for challenging existing inequalities and dependencies. "Powerful Literacies" (Jim Crowther et al.) is an introduction. Section 1 establishes the theoretical and policy frameworks that underpin the book and shows how literacy is situated in different…

Textual Carnivals: The Politics of Composition.

ERIC Educational Resources Information Center

Miller, Susan

This book examines the status of composition in English studies and the uneasy relationship between composition and literature. The three parts of the book (entitled "Where the Carnival Has Been,""The Carnival in the Great American Theme Park: Established Composition," and "Alternative Entertainments") seek to clarify…

Life on the Oregon Trail.

ERIC Educational Resources Information Center

Middle Level Learning: Teaching and Learning Social Studies in the Middle Grades, 1998

1998-01-01

This supplement to "Social Education" and "Social Studies & the Young Learner" seeks to support creative and rigorous social studies teaching in middle schools. The articles show how students can revisit the Oregon Trail through the diaries of children, learn about the five themes of geography (location, place,…

Witches, Ghosts, and Other Apparitions (Rainbow Teachers, Rainbow Students).

ERIC Educational Resources Information Center

Cruz, MaryCarmen; Duff, Ogle Burks

1996-01-01

Describes a number of ghost stories from American cultures, all of which, despite their different origins, seek to stimulate horror, escapism, and fantastic pleasure. Suggests that the stories may be used to improve reading and writing and incorporate "rainbow" themes in the classroom. (TB)

Understanding Student Motivation

ERIC Educational Resources Information Center

Seifert, Timothy

2004-01-01

Contemporary theories of academic motivation seek to explain students' behaviours in academic settings. While each theory seems to possess its own constructs and unique explanations, these theories are actually closely tied together. In this theoretical study of motivation, several theories of motivation were described and an underlying theme of…

Early Childhood Indicators.

ERIC Educational Resources Information Center

Bartlett, Kathy; Zimanyi, Louise

2001-01-01

Recognizing the need to identify the level, nature, and impact of Early Childhood Care and Development (ECCD) programs on children and their families, this theme issue of "Coordinators' Notebook" seeks to complement and further the international efforts at collecting information on ECCD for use at national and international levels.…

How definition of mental health problems can influence help seeking in rural and remote communities.

PubMed

Fuller, J; Edwards, J; Procter, N; Moss, J

2000-06-01

The present study sought to understand the rural and remote influences on people's identification of, and response to, mental health problems. Twenty-two key informants living in northern and western South Australia were interviewed. They included mental health and generalist health professionals, other human service workers and mental health consumers. Three themes are reported here: reluctance to acknowledge mental health problems and the avoidance of appropriate help; stigma and the avoidance of mental health services; and the influence of rural and remote circumstances. Most informants considered that many mental health problems were amenable to help from generalist workers, with backup support from mental health specialists. Informants thought this intervention to be appropriate because a common view of mental health problems as 'insanity' and a culture of self-reliance created a reluctance to seek help from a mental health specialist. These themes need to be taken into account when designing mental health interventions for rural and remote communities.

Galaxy Properties and UV Escape Fractions during the Epoch of Reionization: Results from the Renaissance Simulations

NASA Astrophysics Data System (ADS)

Xu, Hao; Wise, John H.; Norman, Michael L.; Ahn, Kyungjin; O'Shea, Brian W.

2016-12-01

Cosmic reionization is thought to be primarily fueled by the first generations of galaxies. We examine their stellar and gaseous properties, focusing on the star formation rates and the escape of ionizing photons, as a function of halo mass, redshift, and environment using the full suite of the Renaissance Simulations with an eye to provide better inputs to global reionization simulations. This suite probes overdense, average, and underdense regions of the universe of several hundred comoving Mpc3, each yielding a sample of over 3000 halos in the mass range of 107-109.5 {M}⊙ at their final redshifts of 15, 12.5, and 8, respectively. In the process, we simulate the effects of radiative and supernova feedback from 5000 to 10,000 Population III stars in each simulation. We find that halos as small as 107 {M}⊙ are able to host bursty star formation due to metal-line cooling from earlier enrichment by massive Population III stars. Using our large sample, we find that the galaxy-halo occupation fraction drops from unity at virial masses above 108.5 {M}⊙ to ˜50% at 108 {M}⊙ and ˜10% at 107 {M}⊙ , quite independent of redshift and region. Their average ionizing escape fraction is ˜5% in the mass range of 108-109 {M}⊙ and increases with decreasing halo mass below this range, reaching 40%-60% at 107 {M}⊙ . Interestingly, we find that the escape fraction varies between 10%-20% in halos with virial masses of ˜3 × 109 {M}⊙ . Taken together, our results confirm the importance of the smallest galaxies as sources of ionizing radiation contributing to the reionization of the universe.

First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ˜ 7

NASA Astrophysics Data System (ADS)

Zheng, Zhen-Ya; Wang, Junxian; Rhoads, James; Infante, Leopoldo; Malhotra, Sangeeta; Hu, Weida; Walker, Alistair R.; Jiang, Linhua; Jiang, Chunyan; Hibon, Pascale; Gonzalez, Alicia; Kong, Xu; Zheng, XianZhong; Galaz, Gaspar; Barrientos, L. Felipe

2017-06-01

We present the first results from the ongoing Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) project, which is the largest narrowband survey for z ˜ 7 galaxies to date. Using a specially built narrowband filter NB964 for the superb large-area Dark Energy Camera (DECam) on the NOAO/CTIO 4 m Blanco telescope, LAGER has collected 34 hr NB964 narrowband imaging data in the 3 deg2 COSMOS field. We have identified 23 Lyα Emitter candidates at z = 6.9 in the central 2-deg2 region, where DECam and public COSMOS multi-band images exist. The resulting luminosity function (LF) can be described as a Schechter function modified by a significant excess at the bright end (four galaxies with L Lyα ˜ 1043.4±0.2 erg s-1). The number density at L Lyα ˜ 1043.4±0.2 erg s-1 is little changed from z = 6.6, while at fainter L Lyα it is substantially reduced. Overall, we see a fourfold reduction in Lyα luminosity density from z = 5.7 to z = 6.9. Combined with a more modest evolution of the continuum UV luminosity density, this suggests a factor of ˜3 suppression of Lyα by radiative transfer through the z ˜ 7 intergalactic medium (IGM). It indicates an IGM neutral fraction of x H I ˜ 0.4-0.6 (assuming Lyα velocity offsets of 100-200 km s-1). The changing shape of the Lyα LF between z ≲ 6.6 and z = 6.9 supports the hypothesis of ionized bubbles in a patchy reionization at z ˜ 7.

The little Galaxies that could (reionize the universe): predicting faint end slopes & escape fractions at z>4

NASA Astrophysics Data System (ADS)

Anderson, Lauren; Governato, F.; Karcher, M.; Quinn, T.; Wadsley, J.

2017-07-01

The sources that reionized the universe are still unknown, but likely candidates are faint but numerous galaxies. In this paper, we present results from running a high-resolution, uniform volume simulation, the Vulcan, to predict the number densities of undetectable, faint galaxies and their escape fractions of ionizing radiation, fesc, during reionization. Our approach combines a high spatial resolution, a realistic treatment of feedback and hydroprocesses, a strict threshold for minimum number of resolution elements per galaxy, and a converged measurement of fesc. We calibrate our physical model using a novel approach to create realistic galaxies at z = 0, so the simulation is predictive at high redshifts. With this approach, we can (1) robustly predict the evolution of the galaxy UV luminosity function at faint magnitudes down to MUV ˜ -15, two magnitudes fainter than observations, and (2) estimate fesc over a large range of galaxy masses based on the detailed stellar and gas distributions in resolved galaxies. We find steep faint end slopes, implying high number densities of faint galaxies, and the dependence of fesc on the UV magnitude of a galaxy, given by the power law: log fesc = (0.51 ± 0.04)MUV + 7.3 ± 0.8, with the faint population having fesc ˜ 35 per cent. Convolving the UV luminosity function with fesc(MUV), we find an ionizing emissivity that is (1) dominated by the faintest galaxies and (2) reionizes the universe at the appropriate rate, consistent with observational constraints of the ionizing emissivity and the optical depth to the decoupling surface τes, without the need for additional sources of ionizing radiation.

THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. II. CHARACTERIZATION OF SPECTRAL STRUCTURE WITH ELECTROMAGNETIC SIMULATIONS AND ITS SCIENCE IMPLICATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ewall-Wice, Aaron; Hewitt, Jacqueline; Neben, Abraham R.

We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish’s design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA’s suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA’s ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effectivemore » for increasing the sensitivity of EoR experiments at a relatively low cost. We find that electromagnetic resonances in the HERA feed’s cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below k {sub ∥} ≲ 0.2 h Mpc{sup -1}, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.« less

Chemical constraints on the contribution of population III stars to cosmic reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulkarni, Girish; Hennawi, Joseph F.; Rollinde, Emmanuel

2014-05-20

Recent studies have highlighted that galaxies at z = 6-8 fall short of producing enough ionizing photons to reionize the intergalactic medium, and suggest that Population III stars could resolve this tension, because their harder spectra can produce ∼10 × more ionizing photons than Population II. We use a semi-analytic model of galaxy formation, which tracks galactic chemical evolution, to gauge the impact of Population III stars on reionization. Population III supernovae produce distinct metal abundances, and we argue that the duration of the Population III era can be constrained by precise relative abundance measurements in high-z damped Lyα absorbersmore » (DLAs), which provide a chemical record of past star formation. We find that a single generation of Population III stars can self-enrich galaxies above the critical metallicity Z {sub crit} = 10{sup –4} Z {sub ☉} for the Population III-to-II transition, on a very short timescale t {sub self-enrich} ∼ 10{sup 6} yr, owing to the large metal yields and short lifetimes of Population III stars. This subsequently terminates the Population III era, so they contribute ≳ 50% of the ionizing photons only for z ≳ 30, and at z = 10 contribute <1%. The Population III contribution can be increased by delaying metal mixing into the interstellar medium. However, comparing the resulting metal abundance pattern to existing measurements in z ≲ 6 DLAs, we show that the observed [O/Si] ratios of absorbers rule out Population III stars being a major contributor to reionization. Future abundance measurements of z ∼ 7-8 QSOs and gamma-ray bursts should probe the era when the chemical vestiges of Population III star formation become detectable.« less

Hydrogen Epoch of Reionization Array (HERA)

NASA Astrophysics Data System (ADS)

DeBoer, David R.; Parsons, Aaron R.; Aguirre, James E.; Alexander, Paul; Ali, Zaki S.; Beardsley, Adam P.; Bernardi, Gianni; Bowman, Judd D.; Bradley, Richard F.; Carilli, Chris L.; Cheng, Carina; de Lera Acedo, Eloy; Dillon, Joshua S.; Ewall-Wice, Aaron; Fadana, Gcobisa; Fagnoni, Nicolas; Fritz, Randall; Furlanetto, Steve R.; Glendenning, Brian; Greig, Bradley; Grobbelaar, Jasper; Hazelton, Bryna J.; Hewitt, Jacqueline N.; Hickish, Jack; Jacobs, Daniel C.; Julius, Austin; Kariseb, MacCalvin; Kohn, Saul A.; Lekalake, Telalo; Liu, Adrian; Loots, Anita; MacMahon, David; Malan, Lourence; Malgas, Cresshim; Maree, Matthys; Martinot, Zachary; Mathison, Nathan; Matsetela, Eunice; Mesinger, Andrei; Morales, Miguel F.; Neben, Abraham R.; Patra, Nipanjana; Pieterse, Samantha; Pober, Jonathan C.; Razavi-Ghods, Nima; Ringuette, Jon; Robnett, James; Rosie, Kathryn; Sell, Raddwine; Smith, Craig; Syce, Angelo; Tegmark, Max; Thyagarajan, Nithyanandan; Williams, Peter K. G.; Zheng, Haoxuan

2017-04-01

The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization (z = 6-12), and to explore earlier epochs of our Cosmic Dawn (z ˜ 30). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14 m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA’s scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology.

Lyα-emitting galaxies as a probe of reionization: large-scale bubble morphology and small-scale absorbers

NASA Astrophysics Data System (ADS)

Kakiichi, Koki; Dijkstra, Mark; Ciardi, Benedetta; Graziani, Luca

2016-12-01

The visibility of Lyα-emitting galaxies during the Epoch of Reionization is controlled by both diffuse H I patches in large-scale bubble morphology and small-scale absorbers. To investigate their impacts on Lyα transfer, we apply a novel combination of analytic modelling and cosmological hydrodynamical, radiative transfer simulations to three reionization models: (I) the `bubble' model, where only diffuse H I outside ionized bubbles is present; (II) the `web' model, where H I exists only in overdense self-shielded gas; and (III) the hybrid `web-bubble' model. The three models can explain the observed Lyα luminosity function equally well, but with very different H I fractions. This confirms a degeneracy between the ionization topology of the intergalactic medium (IGM) and the H I fraction inferred from Lyα surveys. We highlight the importance of the clustering of small-scale absorbers around galaxies. A combined analysis of the Lyα luminosity function and the Lyα fraction can break this degeneracy and provide constraints on the reionization history and its topology. Constraints can be improved by analysing the full MUV-dependent redshift evolution of the Lyα fraction of Lyman break galaxies. We find that the IGM-transmission probability distribution function is unimodal for bubble models and bimodal in web models. Comparing our models to observations, we infer that the neutral fraction at z ˜ 7 is likely to be of the order of tens of per cent when interpreted with bubble or web-bubble models, with a conservative lower limit ˜1 per cent when interpreted with web models.

An Analysis of the Climate Data Initiative's Data Collection

NASA Astrophysics Data System (ADS)

Ramachandran, R.; Bugbee, K.

2015-12-01

The Climate Data Initiative (CDI) is a broad multi-agency effort of the U.S. government that seeks to leverage the extensive existing federal climate-relevant data to stimulate innovation and private-sector entrepreneurship to support national climate-change preparedness. The CDI project is a systematic effort to manually curate and share openly available climate data from various federal agencies. To date, the CDI has curated seven themes, or topics, relevant to climate change resiliency. These themes include Coastal Flooding, Food Resilience, Water, Ecosystem Vulnerability, Human Health, Energy Infrastructure, and Transportation. Each theme was curated by subject matter experts who selected datasets relevant to the topic at hand. An analysis of the entire Climate Data Initiative data collection and the data curated for each theme offers insights into which datasets are considered most relevant in addressing climate resiliency. Other aspects of the data collection will be examined including which datasets were the most visited or popular and which datasets were the most sought after for curation by the theme teams. Results from the analysis of the CDI collection will be presented in this talk.

Re-ionization and decaying dark matter

NASA Technical Reports Server (NTRS)

Dodelson, Scott; Jubas, Jay M.

1991-01-01

Gunn-Peterson tests suggest that the Universe was reionized after the standard recombination epoch. A systematic treatment is presented of the ionization process by deriving the Boltzmann equations appropriate to this regime. A compact solution for the photon spectrum is found in terms of the ionization ratio. These equations are then solved numerically for the Decaying Dark Matter scenario, wherein neutrinos with mass of order 30 eV radiatively decay producing photons which ionize the intergalactic medium. It was found that the neutrino mass and lifetime are severely constrained by Gunn-Peterson tests, observations of the diffuse photon spectrum in the ultraviolet regime, and the Hubble parameter.

Elucidating dark energy with future 21 cm observations at the epoch of reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohri, Kazunori; Oyama, Yoshihiko; Sekiguchi, Toyokazu

2017-02-01

We investigate how precisely we can determine the nature of dark energy such as the equation of state (EoS) and its time dependence by using future observations of 21 cm fluctuations at the epoch of reionization (06.8∼< z ∼<1) such as Square Kilometre Array (SKA) and Omniscope in combination with those from cosmic microwave background, baryon acoustic oscillation, type Ia supernovae and direct measurement of the Hubble constant. We consider several parametrizations for the EoS and find that future 21 cm observations will be powerful in constraining models of dark energy, especially when its EoS varies at high redshifts.

Lithographed spectrometers for tomographic line mapping of the Epoch of Reionization

NASA Astrophysics Data System (ADS)

O'Brient, R.; Bock, J. J.; Bradford, C. M.; Crites, A.; Duan, R.; Hailey-Dunsheath, S.; Hunacek, J.; LeDuc, R.; Shirokoff, E.; Staniszewski, Z.; Turner, A.; Zemcov, M.

2014-08-01

The Tomographic Ionized carbon Mapping Experiment (TIME) is a multi-phased experiment that will topographically map [CII] emission from the Epoch of Reionization. We are developing lithographed spectrometers that couple to TES bolometers in anticipation of the second generation instrument. Our design intentionally mirrors many features of the parallel SuperSpec project, inductively coupling power from a trunk-line microstrip onto half-wave resonators. The resonators couple to a rat-race hybrids that feeds TES bolometers. Our 25 channel prototype shows spectrally positioned lines roughly matching design with a receiver optical efficiency of 15-20%, a level that is dominated by loss in components outside the spectrometer.

Dark-ages reionization and galaxy formation simulation - IX. Economics of reionizing galaxies

NASA Astrophysics Data System (ADS)

Duffy, Alan R.; Mutch, Simon J.; Poole, Gregory B.; Geil, Paul M.; Kim, Han-Seek; Mesinger, Andrei; Wyithe, J. Stuart B.

2017-09-01

Using a series of high-resolution hydrodynamical simulations we show that during the rapid growth of high-redshift (z > 5) galaxies, reserves of molecular gas are consumed over a time-scale of 300 Myr, almost independent of feedback scheme. We find that there exists no such simple relation for the total gas fractions of these galaxies, with little correlation between gas fractions and specific star formation rates. The bottleneck or limiting factor in the growth of early galaxies is in converting infalling gas to cold star-forming gas. Thus, we find that the majority of high-redshift dwarf galaxies are effectively in recession, with demand (of star formation) never rising to meet supply (of gas), irrespective of the baryonic feedback physics modelled. We conclude that the basic assumption of self-regulation in galaxies - that they can adjust total gas consumption within a Hubble time - does not apply for the dwarf galaxies thought to be responsible for providing most UV photons to reionize the high-redshift Universe. We demonstrate how this rapid molecular time-scale improves agreement between semi-analytic model predictions of the early Universe and observed stellar mass functions.

Polarized Power Spectra from HERA-19 Commissioning Data: Effect of Calibration Techniques

NASA Astrophysics Data System (ADS)

Chichura, Paul; Igarashi, Amy; Fox Fortino, Austin; Kohn, Saul; Aguirre, James; HERA Collaboration

2018-01-01

Studying the Epoch of Reionization (EOR) is crucial for cosmologists as it not only provides information about the first generation of stars and galaxies, but it may also help answer any number of fundamental astrophysical questions. The Hydrogen Epoch of Reionization Array (HERA) is doing this by examining emission from the 21cm hyperfine transition of neutral hydrogen, which has been identified as a promising probe of reionization. Currently, HERA is still in its commissioning phase; 37 of the planned 350 dishes have been constructed and analysis has begun for data received from the first 19 dishes built. With the creation of fully polarized power spectra, we investigate how different data calibration techniques affect the power spectra and whether or not ordering these techniques in different ways affects the results. These calibration techniques include using both non-imaging redundant measurements within the array to calibrate, as well as more traditional approaches based on imaging and calibrating to a model of sky. We explore the degree to which the different calibration schemes affect leakage of foreground emission to regions of Fourier space where EoR the power spectrum is expected to be measurable.

Unlocking Sensitivity for Visibility-based Estimators of the 21 cm Reionization Power Spectrum

NASA Astrophysics Data System (ADS)

Zhang, Yunfan Gerry; Liu, Adrian; Parsons, Aaron R.

2018-01-01

Radio interferometers designed to measure the cosmological 21 cm power spectrum require high sensitivity. Several modern low-frequency interferometers feature drift-scan antennas placed on a regular grid to maximize the number of instantaneously coherent (redundant) measurements. However, even for such maximum-redundancy arrays, significant sensitivity comes through partial coherence between baselines. Current visibility-based power-spectrum pipelines, though shown to ease control of systematics, lack the ability to make use of this partial redundancy. We introduce a method to leverage partial redundancy in such power-spectrum pipelines for drift-scan arrays. Our method cross-multiplies baseline pairs at a time lag and quantifies the sensitivity contributions of each pair of baselines. Using the configurations and beams of the 128-element Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER-128) and staged deployments of the Hydrogen Epoch of Reionization Array, we illustrate how our method applies to different arrays and predict the sensitivity improvements associated with pairing partially coherent baselines. As the number of antennas increases, we find partial redundancy to be of increasing importance in unlocking the full sensitivity of upcoming arrays.

COSMIC REIONIZATION ON COMPUTERS: NUMERICAL AND PHYSICAL CONVERGENCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y., E-mail: gnedin@fnal.gov; Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637; Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637

In this paper I show that simulations of reionization performed under the Cosmic Reionization On Computers project do converge in space and mass, albeit rather slowly. A fully converged solution (for a given star formation and feedback model) can be determined at a level of precision of about 20%, but such a solution is useless in practice, since achieving it in production-grade simulations would require a large set of runs at various mass and spatial resolutions, and computational resources for such an undertaking are not yet readily available. In order to make progress in the interim, I introduce a weakmore » convergence correction factor in the star formation recipe, which allows one to approximate the fully converged solution with finite-resolution simulations. The accuracy of weakly converged simulations approaches a comparable, ∼20% level of precision for star formation histories of individual galactic halos and other galactic properties that are directly related to star formation rates, such as stellar masses and metallicities. Yet other properties of model galaxies, for example, their H i masses, are recovered in the weakly converged runs only within a factor of 2.« less

Meaning in life: the perspective of long-term care residents.

PubMed

Welsh, Darlene; Moore, Sharon L; Getzlaf, Beverley A

2012-07-01

A qualitative approach was used in the exploration of meaning in life for long-term care (LTC) residents. This hermeneutic phenomenological study, as described by van Manen, was conducted using semi-structured interviews with 11 LTC residents from a rural region in Atlantic Canada. Four themes emerged as enhancing meaning in life for the residents in this study: Connectedness, Survival Despite Declining Functional Capacity, Engaging in "Normal" Activities, and Seeking a Place of Refuge. In this article, we describe the emerging themes and the implications for LTC education, practice, and future research. Copyright 2012, SLACK Incorporated.

Accustomed to enduring: experiences of African-American women seeking care for cardiac symptoms.

PubMed

Banks, Angela D; Malone, Ruth E

2005-01-01

Understand the meaning of delayed treatment seeking in African-American women with unstable angina and myocardial infarction. Phenomenologic analysis of in-depth interview data and field notes on 12 African-American women hospitalized with unstable angina or myocardial infarction. Women's interpretation of and response to symptoms were informed by experiences of marginalization and their self-understanding as people who were strong and who had endured life's hardships. When hospitalized, some women experienced trivialization of their complaints by clinicians and a focus on technological procedures over respectfully attending to their concerns, which provided further disincentives to seeking care. Three major themes emerged: misrecognition and discounting of symptoms, enduring, and influence of faith. Experiences of marginalization shape responses to symptoms, care-seeking behavior, and interpretation of subsequent care experiences for African-American women with cardiac disease, who may experience different symptoms as well as interpret them differently than members of other groups.

THE PRIMEVAL POPULATIONS OF THE ULTRA-FAINT DWARF GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.

We present new constraints on the star formation histories of the ultra-faint dwarf (UFD) galaxies, using deep photometry obtained with the Hubble Space Telescope (HST). A galaxy class recently discovered in the Sloan Digital Sky Survey, the UFDs appear to be an extension of the classical dwarf spheroidals to low luminosities, offering a new front in efforts to understand the missing satellite problem. They are the least luminous, most dark-matter-dominated, and least chemically evolved galaxies known. Our HST survey of six UFDs seeks to determine if these galaxies are true fossils from the early universe. We present here the preliminarymore » analysis of three UFD galaxies: Hercules, Leo IV, and Ursa Major I. Classical dwarf spheroidals of the Local Group exhibit extended star formation histories, but these three Milky Way satellites are at least as old as the ancient globular cluster M92, with no evidence for intermediate-age populations. Their ages also appear to be synchronized to within {approx}1 Gyr of each other, as might be expected if their star formation was truncated by a global event, such as reionization.« less

Helper Therapy in an Online Suicide Prevention Community

ERIC Educational Resources Information Center

Greidanus, Elaine; Everall, Robin D.

2010-01-01

Individuals who feel comfortable using Internet-based communication often seek help online when they are feeling distressed. This study examines an online community formed to provide support for distressed adolescents. Content analysis revealed themes in a series of online postings from youth who were experiencing suicidal thoughts. Youth…

School Counselors: A Review of Contemporary Issues

ERIC Educational Resources Information Center

Bain, Steve F.

2012-01-01

This article seeks to review the topic of school counselors and the contemporary issues surrounding this profession. An introduction to the profession and overview of its history provides a comprehensive basis on which to understand today's school counseling profession. An examination of contemporary themes of school counseling will include job…

The future of arid grasslands: identifying issues, seeking solutions

Treesearch

Barbara Tallman; Deborah M. Finch; Carl Edminster; Robert Hamre

1998-01-01

This conference was designed to provide a non-confrontational setting for a variety of people from differing viewpoints to discuss the threats facing arid grasslands of the Southwest. Participants included ranchers and other private economists, scientists, and students. The sessions were organized around the major themes of understanding grasslands, identifying...

#MyDepressionLooksLike: Examining Public Discourse About Depression on Twitter

PubMed Central

Lachmar, E Megan; Bogen, Katherine W; McCauley, Heather L

2017-01-01

Background Social media provides a context for billions of users to connect, express sentiments, and provide in-the-moment status updates. Because Twitter users tend to tweet emotional updates from daily life, the platform provides unique insights into experiences of mental health problems. Depression is not only one of the most prevalent health conditions but also carries a social stigma. Yet, opening up about one’s depression and seeking social support may provide relief from symptoms. Objective The aim of this study was to examine the public discourse of the trending hashtag #MyDepressionLooksLike to look more closely at how users talk about their depressive symptoms on Twitter. Methods We captured 3225 original content tweets for the hashtag #MyDepressionLooksLike that circulated in May of 2016. Eliminating public service announcements, spam, and tweets with links to pictures or videos resulted in a total of 1978 tweets. Using qualitative content analysis, we coded the tweets to detect themes. Results The content analysis revealed seven themes: dysfunctional thoughts, lifestyle challenges, social struggles, hiding behind a mask, apathy and sadness, suicidal thoughts and behaviors, and seeking relief. Conclusions The themes revealed important information about the content of the public messages that people share about depression on Twitter. More research is needed to understand the effects of the hashtag on increasing social support for users and reducing social stigma related to depression. PMID:29046270

Dr Google and the consumer: a qualitative study exploring the navigational needs and online health information-seeking behaviors of consumers with chronic health conditions.

PubMed

Lee, Kenneth; Hoti, Kreshnik; Hughes, Jeffery David; Emmerton, Lynne

2014-12-02

The abundance of health information available online provides consumers with greater access to information pertinent to the management of health conditions. This is particularly important given an increasing drive for consumer-focused health care models globally, especially in the management of chronic health conditions, and in recognition of challenges faced by lay consumers with finding, understanding, and acting on health information sourced online. There is a paucity of literature exploring the navigational needs of consumers with regards to accessing online health information. Further, existing interventions appear to be didactic in nature, and it is unclear whether such interventions appeal to consumers' needs. Our goal was to explore the navigational needs of consumers with chronic health conditions in finding online health information within the broader context of consumers' online health information-seeking behaviors. Potential barriers to online navigation were also identified. Semistructured interviews were conducted with adult consumers who reported using the Internet for health information and had at least one chronic health condition. Participants were recruited from nine metropolitan community pharmacies within Western Australia, as well as through various media channels. Interviews were audio-recorded, transcribed verbatim, and then imported into QSR NVivo 10. Two established approaches to thematic analysis were adopted. First, a data-driven approach was used to minimize potential bias in analysis and improve construct and criterion validity. A theory-driven approach was subsequently used to confirm themes identified by the former approach and to ensure identified themes were relevant to the objectives. Two levels of analysis were conducted for both data-driven and theory-driven approaches: manifest-level analysis, whereby face-value themes were identified, and latent-level analysis, whereby underlying concepts were identified. We conducted 17 interviews, with data saturation achieved by the 14th interview. While we identified a broad range of online health information-seeking behaviors, most related to information discussed during consumer-health professional consultations such as looking for information about medication side effects. The barriers we identified included intrinsic barriers, such as limited eHealth literacy, and extrinsic barriers, such as the inconsistency of information between different online sources. The navigational needs of our participants were extrinsic in nature and included health professionals directing consumers to appropriate online resources and better filtering of online health information. Our participants' online health information-seeking behaviors, reported barriers, and navigational needs were underpinned by the themes of trust, patient activation, and relevance. This study suggests that existing interventions aimed to assist consumers with navigating online health information may not be what consumers want or perceive they need. eHealth literacy and patient activation appear to be prevalent concepts in the context of consumers' online health information-seeking behaviors. Furthermore, the role for health professionals in guiding consumers to quality online health information is highlighted.

James Webb Space Telescope: Large Deployable Cryogenic Telescope in Space

NASA Technical Reports Server (NTRS)

Lightsey, Paul A.; Atkinson, Charles; Clampin, Mark; Feinberg, Lee D.

2012-01-01

The James Webb Space Telescope (JWST) is an infrared space telescope designed to explore four major science themes: first light and reionization, the assembly of galaxies, the birth of stars and protoplanetary systems, and planetary systems and origins of life. JWST is a segmented architecture telescope with an aperture of 6.6 m. It will operate at cryogenic temperature (40 K), achieved via passive cooling, in an orbit about the Earth-Sun second Lagrange point (L2). Passive cooling is facilitated by means of a large sunshield that provides thermal isolation and protection from direct illumination from the Sun. The large size of the telescope and spacecraft systems require that they are stowed for launch in a configuration that fits the Ariane 5 fairing, and then deployed after launch. Routine wavefront sensing and control measurements are used to achieve phasing of the segmented primary mirror and initial alignment of the telescope. A suite of instruments will provide the capability to observe over a spectral range from 0.6- to 27-micron wavelengths with imaging and spectroscopic configurations. An overview is presented of the architecture and selected optical design features of JWST are described

The Enigma of Rapid Repeat Pregnancy: A Qualitative Study of Teen Mothers.

PubMed

Conroy, K N; Engelhart, T G; Martins, Y; Huntington, N L; Snyder, A F; Coletti, K D; Cox, J E

2016-06-01

Rapid repeat pregnancy accounts for 18% of teen pregnancies and leads to adverse health, economic, and developmental outcomes for teen mothers and their children. Few interventions have been successful in reducing rapid repeat pregnancy. In this qualitative study we examined adolescent mothers' perceptions of their decision-making and behaviors that helped prevent or promote a rapid repeat pregnancy. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Semistructured interviews were conducted with 31 adolescent mothers, aged 16-21 years; 15 of these subjects experienced a repeat pregnancy within a year of their first child's birth and 16 had not. Two researchers used a grounded, inductive technique to identify emergent themes; interviews were subsequently coded accordingly. Counts were tabulated of the number of times themes were endorsed among those with or without a repeat pregnancy. Four overarching themes emerged from the interviews: intentionality regarding pregnancy planning, patients' degree of independence in making contraceptive choices, sense of control over life experience, and barriers to follow-through on contraceptive planning. Teens who had not experienced a rapid repeat pregnancy more often endorsed themes of intentionality in preventing or promoting a pregnancy, independence in decision-making, and feelings of control over their experience. Ambivalence and lack of decision-making about seeking another pregnancy were frequently endorsed by mothers who had experienced a second pregnancy. Decision-making regarding seeking or preventing a rapid repeat pregnancy is complex for teen mothers; techniques to help support decision-making or to delay pregnancy until decision-repeat making is complete might be important in reducing rapid pregnancy. Copyright © 2015 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Postpartum Depression Among Asian Indian Mothers.

PubMed

Goyal, Deepika; Park, Van Ta; McNiesh, Susan

2015-01-01

To explore Asian Indian mothers' perspectives of postpartum depression (PPD) and mental health help-seeking behavior. Qualitative exploratory design. Using convenience sampling, postpartum mothers were recruited through flyers posted in public places and on social media sites. Postpartum depression risk was assessed with the Edinburgh Postnatal Depression Scale (EPDS) prior to qualitative interviews. Content analysis methods were used to extract themes from participant narratives. Twelve self-identified, married, Asian Indian mothers, aged between 29 and 40 years, living in Northern California, who gave birth to a healthy infant within the last 12 months, took part in this study. Scores on the EPDS indicated two participants were at an increased risk for developing PPD. Content analysis revealed two emerging themes: (1) Culture-specific postpartum practices and ceremonies and their role in maternal-infant postpartum recovery; and (2) Maternal mental health help-seeking behavior. Nurses taking care of women during the extended prenatal and postpartum period have the unique opportunity to build rapport with their patients which can offer a window of opportunity to educate and help dispel myths about PPD symptoms and treatment. To promote successful maternal-infant outcomes, PPD education should be initiated at the first prenatal appointment, continue during the pregnancy, and be incorporated into well-baby visits through the first postpartum year. Education should include signs and symptoms of PPD as well as importance of timely mental-health help-seeking.

Promoting and Protecting Against Stigma in Assisted Living and Nursing Homes

PubMed Central

Zimmerman, Sheryl; Dobbs, Debra; Roth, Erin G.; Goldman, Susan; Peeples, Amanda D.; Wallace, Brandy

2016-01-01

Purpose of the Study: To determine the extent to which structures and processes of care in multilevel settings (independent living, assisted living, and nursing homes) result in stigma in assisted living and nursing homes. Design and Methods: Ethnographic in-depth interviews were conducted in 5 multilevel settings with 256 residents, families, and staff members. Qualitative analyses identified the themes that resulted when examining text describing either structures of care or processes of care in relation to 7 codes associated with stigma. Results: Four themes related to structures of care and stigma were identified, including the physical environment, case mix, staff training, and multilevel settings; five themes related to processes of care and stigma, including dining, independence, respect, privacy, and care provision. For each theme, examples were identified illustrating how structures and processes of care can potentially promote or protect against stigma. Implications: In no instance were examples or themes identified that suggested the staff intentionally promoted stigma; on the other hand, there was indication that some structures and processes were intentionally in place to protect against stigma. Perhaps the most important theme is the stigma related to multilevel settings, as it has the potential to reduce individuals’ likelihood to seek and accept necessary care. Results suggest specific recommendations to modify care and reduce stigma. PMID:24928555

RELICS: Reionization Lensing Cluster Survey - Discovering Brightly Lensed Distant Galaxies for JWST

NASA Astrophysics Data System (ADS)

Coe, Dan; Bradley, Larry; Salmon, Brett; Avila, Roberto J.; Ogaz, Sara; Bradac, Marusa; Huang, Kuang-Han; Strait, Victoria; Hoag, Austin; Sharon, Keren q.; Cerny, Catherine; Paterno-Mahler, Rachel; Johnson, Traci Lin; Mahler, Guillaume; Zitrin, Adi; Sendra Server, Irene; Acebron, Ana; Cibirka, Nathália; Rodney, Steven; Strolger, Louis; Riess, Adam; Dawson, William; Jones, Christine; Andrade-Santos, Felipe; Lovisari, Lorenzo; Czakon, Nicole; Umetsu, Keiichi; Trenti, Michele; Vulcani, Benedetta; Carrasco, Daniela; Livermore, Rachael; Stark, Daniel P.; Mainali, Ramesh; Frye, Brenda; Oesch, Pascal; Lam, Daniel; Toft, Sune; Ryan, Russell; Peterson, Avery; Past, Matthew; Kikuchihara, Shotaro; Ouchi, Masami; Oguri, Masamune

2018-01-01

The Reionization Lensing Cluster Survey (RELICS) Hubble Treasury Program has completed observations of 41 massive galaxy clusters with 188 orbits of HST ACS and WFC3/IR imaging and 390 hours of Spitzer IRAC imaging. This poster presents an overview of the program and data releases. Reduced images, catalogs, and lens models for all clusters are now available on MAST. RELICS is studying the clusters, supernovae, and lensed high-redshift galaxies. A companion poster presents our high-redshift results: over 300 lensed z ~ 6 - 10 candidates, including some of the brightest known at these redshifts (Salmon et al. 2018). These will be excellent targets for detailed follow-up study in JWST Cycle 1 GO proposals.

The faint-end of galaxy luminosity functions at the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Yue, B.; Castellano, M.; Ferrara, A.; Fontana, A.; Merlin, E.; Amorín, R.; Grazian, A.; Mármol-Queralto, E.; Michałowski, M. J.; Mortlock, A.; Paris, D.; Parsa, S.; Pilo, S.; Santini, P.; Di Criscienzo, M.

2018-05-01

During the Epoch of Reionization (EoR), feedback effects reduce the efficiency of star formation process in small halos or even fully quench it. The galaxy luminosity function (LF) may then turn over at the faint-end. We analyze the number counts of z > 5 galaxies observed in the fields of four Frontier Fields (FFs) clusters and obtain constraints on the LF faint-end: for the turn-over magnitude at z ~ 6, MUVT >~-13.3 for the circular velocity threshold of quenching star formation process, vc* <~ 47 km s-1. We have not yet found significant evidence of the presence of feedback effects suppressing the star formation in small galaxies.

"Ya Me Fui" When English Learners Consider Leaving School

ERIC Educational Resources Information Center

Boone, Jeanmarie Hamilton

2013-01-01

This study examines narratives of English learners who have either dropped out or considered dropping out as a result of their experience in high school. This research seeks to determine at which point students left or considered leaving school, which often goes undetected in traditional quantitative data collection methods. The common themes that…

Introductory Guide to Africa.

ERIC Educational Resources Information Center

Wyss, Esther, Ed.

This guide seeks to be a tool for action and a resource for understanding some of the key issues concerning Africa today. Through a series of six sessions, participants focus on a particular theme or issue that links their community with the African context. The six sessions focus on: (1) "Building Connections with Africa"; (2)…

New Perspectives on Documenting Employment and Earnings Outcomes in Vocational Education.

ERIC Educational Resources Information Center

Stevens, David W.; Shi, Jinping

This guide is designed for local and state authorities who seek a better understanding of the performance of their vocational education programs. Its basic theme is management diagnostics. The first section provides a brief introduction to three decades of research that has been conducted on wage records submitted by employers under unemployment…

Child Protection Assessment in Humanitarian Emergencies: Case Studies from Georgia, Gaza, Haiti and Yemen

ERIC Educational Resources Information Center

Ager, Alastair; Blake, Courtney; Stark, Lindsay; Daniel, Tsufit

2011-01-01

Objectives: The paper reviews the experiences of conducting child protection assessments across four humanitarian emergencies where violence and insecurity, directly or indirectly, posed a major threat to children. We seek to identify common themes emerging from these experiences and propose ways to guide the planning and implementation of…

Peace Crane Project: An Interdisciplinary Approach.

ERIC Educational Resources Information Center

LeBert, Linda L.; Calais, Jerry; Cuevas, Phyllis; Fruge', Hugh; Gardiner, Judy Carter; Larmon, Marilyn; Rees, Jocelyn

To model collaboration and to "practice what we teach," a group of faculty members at McNeese State University in Louisiana developed a college-wide theme based on the book, "Sadako and the Thousand Paper Cranes." This book was selected because of the importance of seeking and achieving peace in a world that is struggling and,…

"White Port and Lemon Juice": Notes on Ritual in the New Black Theatre

ERIC Educational Resources Information Center

Steele, Shelby

1973-01-01

The New Black Theatre dramatizes the values it seeks to reaffirm from play to play: ritual is here achieved through the repetition of patterns, symbols and values from drama to drama, using the six literary devices of allegory, symbol, characterization, recurring themes, language styles, and repetition. (Author/JM)

Ballot Measures Reflect K-12 Funding Jitters

ERIC Educational Resources Information Center

Klein, Alyson

2010-01-01

In an election year dominated by the pitched battle for Congress and major governors' races, state ballot measures involving education are largely tied to a similar theme: the burden of funding K-12 programs when state finances are shaky. In some cases, initiatives, constitutional amendments, and other ballot measures seek to tap new sources of…

Educational Challenges of Internal Migrant Girls: A Case Study among Primary School Children in Turkey

ERIC Educational Resources Information Center

Altinyelken, Hulya Kosar

2009-01-01

This article seeks to investigate education-related challenges encountered by internal migrant girls studying at primary schools in Turkey. From the perspectives of participants, the emerging themes included adaptation, language, low socio-economic status, peer relations, discrimination and bullying. These challenges seem to have direct or…

Positing Living to Remember God: An Autoethnography

ERIC Educational Resources Information Center

Badger, Mariza A.

2015-01-01

This dissertation is a qualitative study in which I, the researcher and public school teacher, seek through writing the self in a narrative and evocative autoethnography to explore three emergent themes: My family's six year and six month circumnavigation, spirituality, and important literature that I have shared with other readers that direct our…

Resourcing Change in Small Schools

ERIC Educational Resources Information Center

Anderson, Michelle; White, Simone

2011-01-01

The theme of this article is the challenge that school leaders face in creating the conditions for learning in small schools. We draw on the concepts of "social capital" and "social entrepreneurship" to identify tensions and possibilities for school leaders in a case study of a small rural school as they seek to find resources…

Recognising Change and Seeking Affirmation: Themes for Embedding Indigenous Knowledges on Teaching Practicum

ERIC Educational Resources Information Center

McLaughlin, Juliana M.; Whatman, Susan L.

2015-01-01

The imperative for Indigenous education in Australia is influenced by national political, social and economic discourses as Australian education systems continue to grapple with an agreed aspiration of full participation for Aboriginal and Torres Strait Islander students. Innovations within and policies guiding our education systems are often…

Highlights in the History of the Education of Women.

ERIC Educational Resources Information Center

Zuelow, Margo J.

The history of the education of women from prehistory through the 1960s reveals constant themes. In every period, obstacles reflecting the prevalent social attitudes were placed in the paths of women seeking education. Economic conditions directly affected the status and scope of women's education, although certain disciplines such as religion and…

Information-seeking at a caregiving website: a qualitative analysis.

PubMed

Kernisan, Leslie P; Sudore, Rebecca L; Knight, Sara J

2010-07-28

The Internet is widely used for health information, yet little is known about the online activity of family caregivers of elders, a rapidly growing group. In order to better understand the online information-seeking activity of "e-caregivers" and other visitors at a caregiving website, we undertook a qualitative analysis of survey data from a website marketed as a comprehensive resource for adults caring for aging parents. The objectives were to better understand what types of information are sought by those visiting a website focused on elder-care issues and to identify overarching themes that might inform future development of Internet resources related to caregiving and aging. From March 2008 to March 2009, a 5-question pop-up survey was offered 9662 times and completed 2161 times. For 1838 respondents, included was a free text answer to the question "What were you looking for?" and 1467 offered relevant and detailed responses. The survey also asked about satisfaction with the site, gender of the respondent, and relationship to the individual being cared for. Content analysis was used to develop a coding dictionary, to code responses into information-seeking categories, and to identify overarching themes. Of the respondents (76% of whom were female), 50% indicated they were caring for parents, 17% for themselves only, and 31% for others. Over half (57%) reported finding what they were looking for, and 46% stated they were extremely likely to recommend the website. Frequently mentioned information-seeking categories included "health information," "practical caregiving," and "support." Respondents also requested information related to housing, legal, insurance, and financial issues. Many responses referred to multiple comorbid conditions and complex caregiving situations. Overarching themes included (1) a desire for assistance with a wide range of practical skills and information and (2) help interpreting symptoms and behavior, such as knowing what life impacts to expect over the course of a health condition or treatment. Visitors to a website targeting adults caring for aging parents reported seeking both general information on caregiving and specific assistance with the complex custodial, medical, emotional, and financial aspects of caregiving. Visitors requested both information to build caregiving skills as well as assistance in interpreting and knowing what to expect from symptoms, health conditions, and changes in behavior and relationships. Many desired communication with and support from other caregivers. Health care providers and eHealth developers should expect that many caregivers of elders are using the Internet as a resource. Further research and development is needed to fully realize the Internet's potential for education and support of caregivers.

FY16 Strategic Themes White Paper.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leland, Robert W.

The Science and Technology (S&T) Division 1000 Strategic Plan includes the Themes, Goals, and Actions for FY16. S&T will continue to support the Labs Strategic plan, Mission Areas and Program Management Units by focusing on four strategic themes that align with the targeted needs of the Labs. The themes presented in this plan are Mission Engagement, Bold Outcomes, Collaborative Environment, and the Safety Imperative. Collectively they emphasize diverse, collaborative teams and a self-reliant culture of safety that will deliver on our promise of exceptional service in the national interest like never before. Mission Engagement focuses on increasing collaboration at allmore » levels but with emphasis at the strategic level with mission efforts across the labs. Bold Outcomes seeks to increase the ability to take thoughtful risks with the goal of achieving transformative breakthroughs more frequently. Collaborative environment strives for a self-aware, collaborative working environment that bridges the many cultures of Sandia. Finally, Safety Imperative aims to minimize the risk of serious injury and to continuously strengthen the safety culture. Each of these themes is accompanied by a brief vision statement, several goals, and planned actions to support those goals throughout FY16 and leading into FY17.« less

Religion and the Psychotherapeutic Relationship: Transferential and Countertransferential Dimensions

PubMed Central

Abernethy, Alexis D.; Lancia, Joseph J.

1998-01-01

The salience of religion in society and health care has received increased attention. Recent developments in psychiatry reflect a broader view of religion that includes an appreciation of its adaptive and maladaptive dimensions. An examination of religious counter- transferential and transferential reactions provides a framework for examining religious themes. Case examples illustrate the following critical factors that increase therapists' skill in working with religious themes: 1) monitoring the therapist's own attitude toward religious content, 2) attending to religious content, 3) seeking consultation, and 4) using religious content in interpretations. (The Journal of Psychotherapy Practice and Research 1998; 7:281–289) PMID:9752639

The effects of Dark Matter annihilation on cosmic reionization

DOE PAGES

Kaurov, Alexander A.; Hooper, Dan; Gnedin, Nickolay Y.

2016-12-15

We revisit the possibility of constraining the properties of dark matter (DM) by studying the epoch of cosmic reionization. Previous studies have shown that DM annihilation was unlikely to have provided a large fraction of the photons that ionized the universe, but instead played a subdominant role relative to stars and quasars. The DM, however, begins to efficiently annihilate with the formation of primordial microhalos atmore » $$z\\sim100-200$$, much earlier than the formation of the first stars. Therefore, if DM annihilation ionized the universe at even the percent level over the interval $$z \\sim 20-100$$, it can leave a significant imprint on the global optical depth, $$\\tau$$. Moreover, we show that cosmic microwave background (CMB) polarization data and future 21 cm measurements will enable us to more directly probe the DM contribution to the optical depth. In order to compute the annihilation rate throughout the epoch of reionization, we adopt the latest results from structure formation studies and explore the impact of various free parameters on our results. Here, we show that future measurements could make it possible to place constraints on the dark matter's annihilation cross section that are at a level comparable to those obtained from the observations of dwarf galaxies, cosmic ray measurements, and studies of recombination.« less

The Cosmology Large Angular Scale Surveyor

NASA Technical Reports Server (NTRS)

Harrington, Kathleen; Marriage, Tobias; Ali, Aamir; Appel, John; Bennett, Charles; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe;

EDGES result versus CMB and low-redshift constraints on ionization histories

NASA Astrophysics Data System (ADS)

Witte, Samuel; Villanueva-Domingo, Pablo; Gariazzo, Stefano; Mena, Olga; Palomares-Ruiz, Sergio

2018-05-01

We examine the results from the Experiment to Detect the Global Epoch of Reionization Signature (EDGES), which has recently claimed the detection of a strong absorption in the 21 cm hyperfine transition line of neutral hydrogen, at redshifts demarcating the early stages of star formation. More concretely, we study the compatibility of the shape of the EDGES absorption profile, centered at a redshift of z ˜17.2 , with measurements of the reionization optical depth, the Gunn-Peterson optical depth, and Lyman-α emission from star-forming galaxies, for a variety of possible reionization models within the standard Λ CDM framework (that is, a Universe with a cosmological constant Λ and cold dark matter CDM). When, conservatively, we only try to accommodate the location of the absorption dip, we identify a region in the parameter space of the astrophysical parameters that successfully explains all of the aforementioned observations. However, one of the most abnormal features of the EDGES measurement is the absorption amplitude, which is roughly a factor of 2 larger than the maximum allowed value in the Λ CDM framework. We point out that the simple considered astrophysical models that produce the largest absorption amplitudes are unable to explain the depth of the dip and of reproducing the observed shape of the absorption profile.

Preheating of the Universe by cosmic rays from primordial supernovae at the beginning of cosmic reionization

NASA Astrophysics Data System (ADS)

Sazonov, S.; Sunyaev, R.

2015-12-01

The 21-cm signal from the cosmic reionization epoch can shed light on the history of heating of the primordial intergalactic medium (IGM) at z ˜ 30-10. It has been suggested that X-rays from the first accreting black holes could significantly heat the Universe at these early epochs. Here we propose another IGM heating mechanism associated with the first stars. As known from previous work, the remnants of powerful supernovae (SNe) ending the lives of massive Population III stars could readily expand out of their host dark matter minihaloes into the surrounding IGM, aided by the preceding photo-evaporation of the halo's gas by the UV radiation from the progenitor star. We argue that during the evolution of such a remnant, a significant fraction of the SN kinetic energy can be put into low-energy (E ≲ 30 MeV) cosmic rays that will eventually escape into the IGM. These subrelativistic cosmic rays could propagate through the Universe and heat the IGM by ˜10-100 K by z ˜ 15, before more powerful reionization/heating mechanisms associated with the first galaxies and quasars came into play. Future 21-cm observations could thus constrain the energetics of the first SNe and provide information on the magnetic fields in the primordial IGM.

The Use of the Time Average Visibility for Analyzing HERA-19 Commissioning Data: Effects of Non-Redundancy

NASA Astrophysics Data System (ADS)

Benefo, Roshan; Gallardo, Samavarti; Aguirre, James; La Plante, Paul; HERA Collaboration

2018-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope situated in South Africa designed to observe the universe from redshifts 13 through 6, in order to detect the emission of the 21 cm line from the hydrogen spin-flip transition. We perform 21 cm cosmology due to its relation with reionization; by detecting this emission line, we can identify the timing of reionization, and understand more about the nature of the universe during the birth of the first stars and galaxies. With that, we can understand the heating conditions of the initial universe, providing us a larger picture of the conditions that created the large-scale structure of the universe we observe today. The HERA array currently consists of 19 antennas, spaced in a hexagonal grid pattern. We consider a robust observable, the time-averaged visibility (TAV), which is in principle sensitive to variations in the beam pattern between antenna elements and is easier to measure than the beam pattern itself. We use this TAV to explore the non-redundancy of baselines in the HERA array due either to cross-coupling between antennas (probed by antenna location in the array) or non-uniformity in their manufacture. The TAV may provide a simple way of verifying improvements in antenna element redundancy.

Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Sathyanarayana Rao, Mayuri; Subrahmanyan, Ravi; Udaya Shankar, N.; Chluba, Jens

2017-05-01

Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30-6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal. We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes’ integration.

Emission line galaxies at high redshift and analogs of the sources of cosmic reionization

NASA Astrophysics Data System (ADS)

Schaerer, D.

2017-11-01

We present recent work on emission line galaxies at high redshift and searches for analogs of the sources of cosmic reionization at low redshift. The VIMOS Ultra-Deep Survey (VUDS) carried out at the VLT has assembled more than 7000 spectra of galaxies from z 1.5 to 6 allowing us to address a wide diversity of questions with statistically meaningful samples. From VUDS we have recently identified a sample of CIII] and CIV] emitters at z 2-4 whose properties we present and discuss here (cf. Nakajima et al. 2017; Le Fevre et al. 2017). These objects provide interesting insight into the C/O ratio at high-z, the nature and hardness of their ionizing source, the ionizing photon production, and others. Targeting compact strong emission line galaxies with high [OIII]/[OII] ratios with the COS spectrograph on-board HST, we have recently been able to find several relatively strong Lyman continuum emitters at z 0.3 (Izotov et al. 2016ab). We describe the physical properties of these unique, rare low-z sources, which are found to be comparable to those of typical z>6 galaxies and thus currently the best analogs for the sources of cosmic reionization (cf. Schaerer et al. 2016). We also briefly discuss open questions and future steps.

SARAS 2 Constraints on Global 21 cm Signals from the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Singh, Saurabh; Subrahmanyan, Ravi; Udaya Shankar, N.; Sathyanarayana Rao, Mayuri; Fialkov, Anastasia; Cohen, Aviad; Barkana, Rennan; Girish, B. S.; Raghunathan, A.; Somashekar, R.; Srivani, K. S.

2018-05-01

Spectral distortions in the cosmic microwave background over the 40–200 MHz band are imprinted by neutral hydrogen in the intergalactic medium prior to the end of reionization. This signal, produced in the redshift range z = 6–34 at the rest-frame wavelength of 21 cm, has not been detected yet; and a poor understanding of high-redshift astrophysics results in a large uncertainty in the expected spectrum. The SARAS 2 radiometer was purposely designed to detect the sky-averaged 21 cm signal. The instrument, deployed at the Timbaktu Collective (Southern India) in 2017 April–June, collected 63 hr of science data, which were examined for the presence of the cosmological 21 cm signal. In our previous work, the first-light data from the SARAS 2 radiometer were analyzed with Bayesian likelihood-ratio tests using 264 plausible astrophysical scenarios. In this paper we reexamine the data using an improved analysis based on the frequentist approach and forward-modeling. We show that SARAS 2 data reject 20 models, out of which 15 are rejected at a significance >5σ. All the rejected models share the scenario of inefficient heating of the primordial gas by the first population of X-ray sources, along with rapid reionization. Joint Astronomy Program, Indian Institute of Science, Bangalore 560012, India.

Older partner selection in young African-American men who have sex with men.

PubMed

Arrington-Sanders, Renata; Leonard, Lori; Brooks, Durryle; Celentano, David; Ellen, Jonathan

2013-06-01

Young African-American (AA) men who have sex with men (YAAMSM) have experienced the greatest proportional increase in new HIV cases compared with other groups. Bridging sexual partnerships between YAAMSM and older aged cohorts with higher rates of primary HIV infection has emerged as an important independent risk factor for the development of HIV. We explored reasons young AAMSM cite for being attracted to and seeking an older partner and the interpersonal needs met within older sexual partnerships. Seventeen in-depth semistructured qualitative interviews were conducted in YAAMSM residing in a midsized urban city with high HIV prevalence. Two coders independently evaluated transcribed data to identify/collapse codes that emerged. We analyzed data using categorical and contextualizing analytic methods. Two themes emerged from the text for seeking an older sexual partner: the emotional maturity the older partner represented and the ability of the older partner to expose the younger partner to more life experiences. In addition, two themes emerged around attraction: support and physical attractiveness of the older partner. Few men described seeking age-discordant relationships for the sole purpose of exchange sex. Older partners during first same-sex experience helped younger partners sort through sexual position and how to perform in relationships. These interviews suggest that YAAMSM may be seeking older partners to fulfill desires to be in a stable, emotionally mature relationship and for exposure in the larger community. Prevention strategies aimed at targeting adolescent MSM age-discordant relationships will need to address the interpersonal needs met within older sexual partnerships. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Patients' perceptions and attitudes on recurrent prostate cancer and hormone therapy: Qualitative comparison between decision-aid and control groups.

PubMed

Gorawara-Bhat, Rita; O'Muircheartaigh, Siobhan; Mohile, Supriya; Dale, William

2017-09-01

To compare patients' attitudes towards recurrent prostate cancer (PCa) and starting hormone therapy (HT) treatment in two groups-Decision-Aid (DA) (intervention) and Standard-of-care (SoC) (Control). The present research was conducted at three academic clinics-two in the Midwest and one in the Northeast U.S. Patients with biochemical recurrence of PCa (n=26) and follow-up oncology visits meeting inclusion criteria were randomized to either the SoC or DA intervention group prior to their consultation. Analysts were blinded to group assignment. Semi-structured phone interviews with patients were conducted 1-week post consultation. Interviews were audio-taped and transcribed. Qualitative analytic techniques were used to extract salient themes and conduct a comparative analysis of the two groups. Four salient themes emerged-1) knowledge acquisition, 2) decision-making style, 3) decision-making about timing of HT, and 4) anxiety-coping mechanisms. A comparative analysis showed that patients receiving the DA intervention had a better comprehension of Prostate-specific antigen (PSA), an improved understanding of HT treatment implications, an external locus-of-control, participation in shared decision-making and, support-seeking for anxiety reduction. In contrast, SoC patients displayed worse comprehension of PSA testing and HT treatment implications, internal locus-of-control, unilateral involvement in knowledge-seeking and decision-making, and no support-seeking for anxiety-coping. The DA was more effective than the SoC group in helping PCa patients understand the full implications of PSA testing and treatment; motivating shared decision-making, and support-seeking for anxiety relief. DA DVD interventions can be a useful patient education tool for bringing higher quality decision-making to prostate cancer care. Copyright © 2017 Elsevier Ltd. All rights reserved.

Perceived Barriers and Enablers of Help-Seeking for Substance Use Problems During Adolescence.

PubMed

Berridge, Bonita J; McCann, Terence V; Cheetham, Ali; Lubman, Dan I

2018-01-01

Receiving professional help early can reduce long-term harms associated with substance use. However, little is known about the factors that influence help-seeking for substance use problems during early-mid adolescence, prior to the emergence of disorder. Given that beliefs regarding help-seeking are likely to develop early, understanding adolescent views of help-seeking during this period is likely to provide important information for prevention and intervention efforts. The current study identifies perceptions that would facilitate or prevent adolescents from seeking support for substance use problems from formal and informal help sources. Thirty-four 12- to 16-year-olds from two schools in Melbourne, Victoria, Australia, were recruited. A qualitative interpretative design was used, incorporating semistructured, audio-recorded interviews. Three overlapping themes that reflected barriers or enablers to help-seeking were identified: approachability, confidentiality and trustworthiness, and expertise. Help-seeking was facilitated when adolescents believed that the help source would be supportive and understanding, would keep information confidential, and had expertise in the alcohol and drug field. Conversely, adolescents were reluctant to seek help from sources they believed would be judgmental, lacked expertise, or would inform their parents. These findings highlight perceptions that may influence help-seeking for alcohol and drug problems during adolescence. Further research is needed to determine if help-seeking can be facilitated by improving parents' and peers' knowledge and promoting health professionals' expertise in working with young people's alcohol and drug issues.

A low Lyman Continuum escape fraction of <10 per cent for extreme [O III] emitters in an overdensity at z ˜ 3.5

NASA Astrophysics Data System (ADS)

Naidu, Rohan P.; Forrest, Ben; Oesch, Pascal A.; Tran, Kim-Vy H.; Holden, Bradford P.

2018-07-01

Recent work has suggested that extreme [O III] emitting star-forming galaxies are important to reionization. Relatedly, [O III]/[O II] has been put forward as an indirect estimator of the Lyman Continuum (LyC) escape fraction (fesc) at z ≳ 4.5 when the opaque IGM renders LyC photons unobservable. Using deep archival U-band (VLT/VIMOS) imaging of a recently confirmed overdensity at z˜ 3.5, we calculate tight constraints on fesc for a sample (N = 73) dominated by extreme [O III] emitters. We find no LyC signal (f_esc^rel < 6.3^{+0.7}_{-0.7} per cent at 1σ) in a deep U-band stack of our sample (31.98 mag at 1σ). This constraint is in agreement with recent studies of star-forming galaxies spanning z ˜ 1-4 that have found very low average fesc. Despite the galaxies in our study having an estimated average rest-frame EW([O III]λ5007) ˜ 400 Å and [O III]/[O II] ˜ 4 from composite SED fitting, we find no LyC detection, which brings into question the potential of [O III]/[O II] as an effective probe of the LyC - a majority of LyC emitters have [O III]/[O II] > 3, but we establish here that [O III]/[O II] > 3 does not guarantee significant LyC leakage for a population. Since even extreme star-forming galaxies are unable to produce the f_esc˜ 10-15 per cent required by most theoretical calculations for star-forming galaxies to drive reionization, there must either be a rapid evolution of fesc between z˜ 3.5 and the epoch of reionization, or hitherto observationally unstudied sources [e.g. ultrafaint low-mass galaxies with log (M/M⊙) ˜ 7-8.5] must make an outsized contribution to reionization.

A Low Lyman Continuum Escape Fraction of <10% for Extreme [O III] Emitters in an Overdensity at z˜3.5

NASA Astrophysics Data System (ADS)

Naidu, Rohan P.; Forrest, Ben; Oesch, Pascal A.; Tran, Kim-Vy H.; Holden, Bradford P.

2018-04-01

Recent work has suggested extreme [O III] emitting star-forming galaxies are important to reionization. Relatedly, [O III]/[O II] has been put forward as an indirect estimator of the Lyman Continuum (LyC) escape fraction (fesc) at z ≳ 4.5 when the opaque IGM renders LyC photons unobservable. Using deep archival U-band (VLT/VIMOS) imaging of a recently confirmed overdensity at z ˜ 3.5 we calculate tight constraints on fesc for a sample (N=73) dominated by extreme [O III] emitters. We find no Lyman Continuum signal (f_{esc}^{rel} < 6.3^{+0.7}_{-0.7} % at 1σ) in a deep U-band stack of our sample (31.98 mag at 1σ). This constraint is in agreement with recent studies of star-forming galaxies spanning z ˜ 1 - 4 that have found very low average fesc. Despite the galaxies in our study having an estimated average rest-frame EW([O III]λ5007) ˜ 400Å and [O III]/[O II]˜4 from composite SED-fitting, we find no LyC detection, which brings into question the potential of [O III]/[O II] as an effective probe of the LyC-a majority of LyC emitters have [O III]/[O II]>3, but we establish here that [O III]/[O II]>3 does not guarantee significant LyC leakage for a population. Since even extreme star-forming galaxies are unable to produce the fesc ˜ 10 - 15% required by most theoretical calculations for star-forming galaxies to drive reionization, there must either be a rapid evolution of fesc between z ˜ 3.5 and the Epoch of Reionization, or hitherto observationally unstudied sources (e.g. ultra-faint low-mass galaxies with log (M/M⊙) ˜ 7 - 8.5) must make an outsized contribution to reionization.

Fully coupled simulation of cosmic reionization. I. numerical methods and tests

DOE PAGES

Norman, Michael L.; Reynolds, Daniel R.; So, Geoffrey C.; ...

2015-01-09

Here, we describe an extension of the Enzo code to enable fully coupled radiation hydrodynamical simulation of inhomogeneous reionization in large similar to(100 Mpc)(3) cosmological volumes with thousands to millions of point sources. We solve all dynamical, radiative transfer, thermal, and ionization processes self-consistently on the same mesh, as opposed to a postprocessing approach which coarse-grains the radiative transfer. But, we employ a simple subgrid model for star formation which we calibrate to observations. The numerical method presented is a modification of an earlier method presented in Reynolds et al. differing principally in the operator splitting algorithm we use tomore » advance the system of equations. Radiation transport is done in the gray flux-limited diffusion (FLD) approximation, which is solved by implicit time integration split off from the gas energy and ionization equations, which are solved separately. This results in a faster and more robust scheme for cosmological applications compared to the earlier method. The FLD equation is solved using the hypre optimally scalable geometric multigrid solver from LLNL. By treating the ionizing radiation as a grid field as opposed to rays, our method is scalable with respect to the number of ionizing sources, limited only by the parallel scaling properties of the radiation solver. We test the speed and accuracy of our approach on a number of standard verification and validation tests. We show by direct comparison with Enzo's adaptive ray tracing method Moray that the well-known inability of FLD to cast a shadow behind opaque clouds has a minor effect on the evolution of ionized volume and mass fractions in a reionization simulation validation test. Finally, we illustrate an application of our method to the problem of inhomogeneous reionization in a 80 Mpc comoving box resolved with 3200(3) Eulerian grid cells and dark matter particles.« less

Complementing the ground-based CMB-S4 experiment on large scales with the PIXIE satellite

NASA Astrophysics Data System (ADS)

Calabrese, Erminia; Alonso, David; Dunkley, Jo

2017-03-01

We present forecasts for cosmological parameters from future cosmic microwave background (CMB) data measured by the stage-4 (S4) generation of ground-based experiments in combination with large-scale anisotropy data from the PIXIE satellite. We demonstrate the complementarity of the two experiments and focus on science targets that benefit from their combination. We show that a cosmic-variance-limited measurement of the optical depth to reionization provided by PIXIE, with error σ (τ )=0.002 , is vital for enabling a 5 σ detection of the sum of the neutrino masses when combined with a CMB-S4 lensing measurement and with lower-redshift constraints on the growth of structure and the distance-redshift relation. Parameters characterizing the epoch of reionization will also be tightly constrained; PIXIE's τ constraint converts into σ (zre)=0.2 for the mean time of reionization, and a kinematic Sunyaev-Zel'dovich measurement from S4 gives σ (Δ zre)=0.03 for the duration of reionization. Both PIXIE and S4 will put strong constraints on primordial tensor fluctuations, vital for testing early-Universe models, and will do so at distinct angular scales. We forecast σ (r )≈5 ×10-4 for a signal with a tensor-to-scalar ratio r =10-3, after accounting for diffuse foreground removal and delensing. The wide and dense frequency coverage of PIXIE results in an expected foreground-degradation factor on r of only ≈25 %. By measuring large and small scales PIXIE and S4 will together better limit the energy injection at recombination from dark matter annihilation, with pann<0.09 ×10-6 m3/s /kg projected at 95% confidence. Cosmological parameters measured from the damping tail with S4 will be best constrained by polarization, which has the advantage of minimal contamination from extragalactic emission.

Observable Signatures of Cosmic Reionization and the End of the Dark Ages

NASA Astrophysics Data System (ADS)

Shapiro, Paul R.; Iliev, I. T.; Mellema, G.; Pen, U. L.; McDonald, P.; Bond, J. R.; Alvarez, M.; Ahn, K.

2007-12-01

Reionization exerted a strong feedback effect which left its imprint on all scales and on radiation backgrounds at all wavelengths. When the first stars formed inside minihalos of mass 106 solar masses at z > 20, ionizing radiation heated and expelled the gas inside their minihalos and escaped to create intergalactic H II regions. As these H II regions grew, their ionization fronts encountered other minihalos, which blocked their path and trapped them, causing this minihalo gas, too, to escape in a photoevaporative wind. Further star formation inside minihalos was affected not only by these I-fronts, but also by the rising dissociating background. Eventually, hierarchical clustering formed dwarf galaxies > 108 solar masses, where atomic cooling was effective enough to trigger more star formation, and intergalactic H II regions grew and merged to become 10's of comoving Mpc's in size. Inside these H II regions, gas pressure inhibited gravitational collapse, so the minimum mass of newly-formed galaxies jumped above 109 solar masses. Reionization ended when the intergalactic H II regions finally overlapped everywhere. We have studied this process by a variety of techniques, on a hierarchy of mass- and length-scales. The latter span the range from interiors of minihalos, to giant H II regions produced by the clustered formation of galaxies, to large-scale structure of the patchy distribution of neutral and ionized gas during the epoch of reionization. These results lead to predictions of a fluctuating background of redshifted 21-cm line radiation, temperature and polarization anisotropy of the CMB, gaps in the Gunn-Peterson absorption spectra of high-z quasars, and distortion of the luminosity function and spatial clustering of Lyman alpha emission-line galaxies during this epoch, among other things. I will summarize the latest theoretical developments in this talk. This work supported by NASA grants NNX07AH09G and NNG04GI77G and NSF AST-0708176.

Full-data Results of Hubble Frontier Fields: UV Luminosity Functions at z ∼ 6–10 and a Consistent Picture of Cosmic Reionization

NASA Astrophysics Data System (ADS)

Ishigaki, Masafumi; Kawamata, Ryota; Ouchi, Masami; Oguri, Masamune; Shimasaku, Kazuhiro; Ono, Yoshiaki

2018-02-01

We present UV luminosity functions of dropout galaxies at z∼ 6{--}10 with the complete Hubble Frontier Fields data. We obtain a catalog of ∼450 dropout-galaxy candidates (350, 66, and 40 at z∼ 6{--}7, 8, and 9, respectively), with UV absolute magnitudes that reach ∼ -14 mag, ∼2 mag deeper than the Hubble Ultra Deep Field detection limits. We carefully evaluate number densities of the dropout galaxies by Monte Carlo simulations, including all lensing effects such as magnification, distortion, and multiplication of images as well as detection completeness and contamination effects in a self-consistent manner. We find that UV luminosity functions at z∼ 6{--}8 have steep faint-end slopes, α ∼ -2, and likely steeper slopes, α ≲ -2 at z∼ 9{--}10. We also find that the evolution of UV luminosity densities shows a non-accelerated decline beyond z∼ 8 in the case of {M}trunc}=-15, but an accelerated one in the case of {M}trunc}=-17. We examine whether our results are consistent with the Thomson scattering optical depth from the Planck satellite and the ionized hydrogen fraction Q H II at z≲ 7 based on the standard analytic reionization model. We find that reionization scenarios exist that consistently explain all of the observational measurements with the allowed parameters of {f}esc}={0.17}-0.03+0.07 and {M}trunc}> -14.0 for {log}{ξ }ion}/[{erg}}-1 {Hz}]=25.34, where {f}esc} is the escape fraction, M trunc is the faint limit of the UV luminosity function, and {ξ }ion} is the conversion factor of the UV luminosity to the ionizing photon emission rate. The length of the reionization period is estimated to be {{Δ }}z={3.9}-1.6+2.0 (for 0.1< {Q}{{H}{{II}}}< 0.99), consistent with the recent estimate from Planck.

First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ∼ 7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Zhen-Ya; Jiang, Chunyan; Wang, Junxian

2017-06-20

We present the first results from the ongoing Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) project, which is the largest narrowband survey for z ∼ 7 galaxies to date. Using a specially built narrowband filter NB964 for the superb large-area Dark Energy Camera (DECam) on the NOAO/CTIO 4 m Blanco telescope, LAGER has collected 34 hr NB964 narrowband imaging data in the 3 deg{sup 2} COSMOS field. We have identified 23 Ly α Emitter candidates at z = 6.9 in the central 2-deg{sup 2} region, where DECam and public COSMOS multi-band images exist. The resulting luminosity function (LF)more » can be described as a Schechter function modified by a significant excess at the bright end (four galaxies with L {sub Lyα∼} 10{sup 43.4±0.2} erg s{sup −1}). The number density at L {sub Ly} {sub α} ∼ 10{sup 43.4±0.2} erg s{sup −1} is little changed from z = 6.6, while at fainter L {sub Lyα} it is substantially reduced. Overall, we see a fourfold reduction in Ly α luminosity density from z = 5.7 to z = 6.9. Combined with a more modest evolution of the continuum UV luminosity density, this suggests a factor of ∼3 suppression of Ly α by radiative transfer through the z ∼ 7 intergalactic medium (IGM). It indicates an IGM neutral fraction of x {sub Hi} ∼ 0.4–0.6 (assuming Ly α velocity offsets of 100–200 km s{sup −1}). The changing shape of the Ly α LF between z ≲ 6.6 and z = 6.9 supports the hypothesis of ionized bubbles in a patchy reionization at z ∼ 7.« less

Hubble space telescope/cosmic origins spectrograph observations of the quasar Q0302–003: Probing the He II reionization epoch and QSO proximity effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syphers, David; Shull, J. Michael, E-mail: David.Syphers@colorado.edu

2014-03-20

Q0302–003 (z = 3.2860 ± 0.0005) was the first quasar discovered that showed a He II Gunn-Peterson trough, a sign of incomplete helium reionization at z ≳ 2.9. We present its Hubble Space Telescope/Cosmic Origins Spectrograph far-UV medium-resolution spectrum, which resolves many spectral features for the first time, allowing study of the quasar itself, the intergalactic medium, and quasar proximity effects. Q0302–003 has a harder intrinsic extreme-UV spectral index than previously claimed, as determined from both a direct fit to the spectrum (yielding α{sub ν} ≈ –0.8) and the helium-to-hydrogen ion ratio in the quasar's line-of-sight proximity zone. Intergalactic absorptionmore » along this sightline shows that the helium Gunn-Peterson trough is largely black in the range 2.87 < z < 3.20, apart from ionization due to local sources, indicating that helium reionization has not completed at these redshifts. However, we tentatively report a detection of nonzero flux in the high-redshift trough when looking at low-density regions, but zero flux in higher-density regions. This constrains the He II fraction to be about 1% in the low-density intergalactic medium (IGM) and possibly a factor of a few higher in the IGM as a whole, suggesting helium reionization has progressed substantially by z ∼ 3.1. The Gunn-Peterson trough recovers to a He II Lyα forest at z < 2.87. We confirm a transmission feature due to the ionization zone around a z = 3.05 quasar just off the sightline, and resolve the feature for the first time. We discover a similar such feature possibly caused by a luminous z = 3.23 quasar further from the sightline, which suggests that this quasar has been luminous for >34 Myr.« less

Dark-ages reionization and galaxy-formation simulation- VI. The origins and fate of the highest known redshift galaxy

NASA Astrophysics Data System (ADS)

Mutch, Simon J.; Liu, Chuanwu; Poole, Gregory B.; Geil, Paul M.; Duffy, Alan R.; Trenti, Michele; Oesch, Pascal A.; Illingworth, Garth D.; Mesinger, Andrei; Wyithe, J. Stuart B.

2016-12-01

Using Hubble data, including new grism spectra, Oesch et al. recently identified GN-z11, an MUV = -21.1 galaxy at z = 11.1 (just 400 Myr after the big bang). With an estimated stellar mass of ˜109 M⊙, this galaxy is surprisingly bright and massive, raising questions as to how such an extreme object could form so early in the Universe. Using MERAXES, a semi-analytic galaxy-formation model developed as part of the Dark-ages Reionization And Galaxy-formation Observables from Numerical Simulations (DRAGONS) programme, we investigate the potential formation mechanisms and eventual fate of GN-z11. The volume of our simulation is comparable to that of the discovery observations and possesses two analogue galaxies of similar luminosity to this remarkably bright system. Existing in the two most massive subhaloes at z = 11.1 (Mvir = 1.4 × 1011 M⊙ and 6.7 × 1010 M⊙), our model analogues show excellent agreement with all available observationally derived properties of GN-z11. Although they are relatively rare outliers from the full galaxy population at high-z, they are no longer the most massive or brightest systems by z = 5. Furthermore, we find that both objects possess relatively smooth, but extremely rapid mass growth histories with consistently high star formation rates and UV luminosities at z > 11, indicating that their brightness is not a transient, merger-driven feature. Our model results suggest that future wide-field surveys with the James Webb Space Telescope may be able to detect the progenitors of GN-z11 analogues out to z ˜ 13-14, pushing the frontiers of galaxy-formation observations to the early phases of cosmic reionization and providing a valuable glimpse of the first galaxies to reionize the Universe on large scales.

Over-reassurance and undersupport after a 'false alarm': a systematic review of the impact on subsequent cancer symptom attribution and help seeking.

PubMed

Renzi, Cristina; Whitaker, Katriina L; Wardle, Jane

2015-02-04

This literature review examined research into the impact of a previous 'all-clear' or non-cancer diagnosis following symptomatic presentation ('false alarm') on symptom attribution and delays in help seeking for subsequent possible cancer symptoms. The comprehensive literature review included original research based on quantitative, qualitative and mixed data collection methods. We used a combination of search strategies, including in-depth searches of electronic databases (PubMed, EMBASE, PsychInfo), searching key authors and articles listed as 'related' in PubMed, and reference lists. We performed a narrative synthesis of key themes shared across studies. The review included studies published after 1990 and before February 2014 reporting information on adult patients having experienced a false alarm following symptomatic presentation. We excluded false alarms in the context of screening. We evaluated the effect of a 'false alarm' on symptom attribution and help seeking for new or recurrent possible cancer symptoms. Overall, 1442 papers were screened and 121 retrieved for full-text evaluation. Among them, 19 reported on false alarms and subsequent symptom attribution or help seeking. They used qualitative (n=14), quantitative (n=3) and mixed methods (n=2). Breast (n=7), gynaecological (n=3), colorectal (n=2), testicular (n=2), and head and neck cancers (n=2) were the most studied. Two broad themes emerged underlying delays in help seeking: (1) over-reassurance from the previous 'all-clear' diagnosis leading to subsequent symptoms being interpreted as benign, and (2) unsupportive healthcare experiences in which symptoms were dismissed, leaving patients concerned about appearing hypochondriacal or uncertain about the appropriate next actions. The evidence suggested that the effect of a false alarm can persist for months and even years. In conclusion, over-reassurance and undersupport of patients after a false alarm can undermine help seeking in the case of new or recurrent potential cancer symptoms, highlighting the need for appropriate patient information when investigations rule out cancer. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Online information seeking practices of biology teachers and the perceived influences on instructional planning

NASA Astrophysics Data System (ADS)

Perrault, Anne Marie

The purpose of this study was to examine biology teachers' perceptions of how their online information seeking practices influence their instructional planning. When teachers engage in activities to locate, evaluate, and use online information and resources, a myriad of inter-related and often inseparable consequences follows. These influences may be any combination of direct/indirect, desirable/undesirable, or anticipated/unanticipated (Rogers, 2003). This exploratory study collected baseline data regarding teachers' online practices and its influence on their practice. There were two phases of data collection in this study. Phase I was an online survey of more than seventy New York State biology teachers. The survey was intended to capture (1) a snapshot of the biology teachers' online information seeking practices during the summer and fall 2004, and (2) their perceptions regarding how their online practices influenced their instructional planning. In Phase II, ten study participants were interviewed in order to explore in greater detail the consequences of their online information seeking practices on their instructional planning. Four themes reflecting the consequences of teachers' information seeking practices emerged from the data analysis: Currency of Information; Sparking of Ideas and Gaining Personal Knowledge; Resource Management and the Role of Time; and Webs of Sharing. Each theme encompassed both the purposeful and the indirect actions by teachers to access knowledge and resources to refine and improve their instructional planning. This study's findings show that teachers are using a greater number and wider range of current and multi-modal resources than pre-Internet and they perceive this as an advantage in creating authentic, inquiry-based learning experiences. A notable discovery was of the under-use by teachers of educational online resources specifically designed to support teaching and learning activities (e.g., digital libraries, online databases, and listservs). This study's findings point to a recursive process in which teachers are engaged in ongoing online information seeking practices; continually learning and fostering new knowledge; integrating the learning into their instructional planning practices; changing their teaching strategies; and going back online to search for information and resources and begin the cycle again.

The rise of the first stars: Supersonic streaming, radiative feedback, and 21-cm cosmology

NASA Astrophysics Data System (ADS)

Barkana, Rennan

2016-07-01

Understanding the formation and evolution of the first stars and galaxies represents one of the most exciting frontiers in astronomy. Since the universe was filled with hydrogen atoms at early times, the most promising method for observing the epoch of the first stars is to use the prominent 21-cm spectral line of hydrogen. Current observational efforts are focused on the cosmic reionization era, but observations of the pre-reionization cosmic dawn are also beginning and promise exciting discoveries. While observationally unexplored, theoretical studies predict a rich variety of observational signatures from the astrophysics of the early galaxies that formed during cosmic dawn. As the first stars formed, their radiation (plus that from stellar remnants) produced feedback that radically affected both the intergalactic medium and the character of newly-forming stars. Lyman- α radiation from stars generated a strong 21-cm absorption signal, observation of which is currently the only feasible method of detecting the dominant population of galaxies at redshifts as early as z ∼ 25. Another major player is cosmic heating; if due to soft X-rays, then it occurred fairly early (z ∼ 15) and produced the strongest pre-reionization signal, while if it is due to hard X-rays, as now seems more likely, then it occurred later and may have dramatically affected the 21-cm sky even during reionization. In terms of analysis, much focus has gone to studying the angle-averaged power spectrum of 21-cm fluctuations, a rich dataset that can be used to reconstruct the astrophysical information of greatest interest. This does not, however, diminish the importance of finding additional probes that are complementary or amenable to a more model-independent analysis. Examples include the global (sky-averaged) 21-cm spectrum, and the line-of-sight anisotropy of the 21-cm power spectrum. Another striking feature may result from a recently recognized effect of a supersonic relative velocity between the dark matter and gas. This effect enhanced large-scale clustering and, if early 21-cm fluctuations were dominated by small galactic halos, it produced a prominent pattern on 100 Mpc scales. Work in this field, focused on understanding the whole era of reionization and cosmic dawn with analytical models and numerical simulations, is likely to grow in intensity and importance, as the theoretical predictions are finally expected to confront 21-cm observations in the coming years.

X-Ray Background from Early Binaries

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-11-01

What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different observed X-ray energy (and the total X-ray background is given by the sum of the curves). The two panels show results from two different calculation methods. [Xu et al. 2016]Xu and collaborators have now attempted to model to the impact of this X-ray production from Pop III binaries on the intergalactic medium and determine how much it could have contributed to reionization and the diffuse X-ray background we observe today.Generating a BackgroundThe authorsestimated the X-ray luminosities from Pop III binaries using the results of a series of galaxy-formation simulations, beginning at a redshift of z 25 and evolving up to z = 7.6. They then used these luminosities to calculate the resulting X-ray background.Xu and collaborators find that Pop III binaries can produce significant X-ray radiation throughout the period of reionization, and this radiation builds up gradually into an X-ray background. The team shows that X-rays from Pop III binaries might actually dominate more commonly assumed sources of the X-ray background at high redshifts (such as active galactic nuclei), and this radiation isstrong enough to heat the intergalactic medium to 1000K and ionize a few percent of the neutral hydrogen.If Pop III binaries are indeed this large of a contributor to the X-ray background and to the local and global heating of the intergalactic medium, then its important that we follow up with more detailed modeling to understand what this means for our interpretation of cosmological observations.CitationHao Xu et al 2016 ApJL 832 L5. doi:10.3847/2041-8205/832/1/L5

The faces of breastfeeding support: Experiences of mothers seeking breastfeeding support online.

PubMed

Bridges, Nicole

2016-03-01

The aim of this study was to advance understanding of the experiences of mothers using closed Facebook groups attached to the Australian Breastfeeding Association (ABA) and how these mothers find and share breastfeeding support and information using this forum. The study involved members of three closed Facebook groups that were chosen as interesting cases for study, based on the volume and nature of their posts. Members of these three groups then participated in online depth interviews and online semi-structured focus groups. The overarching theme identified was support, with four sub-themes that describe the nature of online breastfeeding support within the Facebook environment. These sub-themes are: community, complementary, immediate and information. It was found that social networking sites (SNSs) provide support from the trusted community. It is immediate, it complements existing support or services that ABA provides and also provides practical and valuable information for its users.

Designing a leadership development program for surgeons.

PubMed

Jaffe, Gregory A; Pradarelli, Jason C; Lemak, Christy Harris; Mulholland, Michael W; Dimick, Justin B

2016-01-01

Although numerous leadership development programs (LDPs) exist in health care, no programs have been specifically designed to meet the needs of surgeons. This study aimed to elicit practicing surgeons' motivations and desired goals for leadership training to design an evidence-based LDP in surgery. At a large academic health center, we conducted semistructured interviews with 24 surgical faculty members who voluntarily applied and were selected for participation in a newly created LDP. Transcriptions of the interviews were analyzed using analyst triangulation and thematic coding to extract major themes regarding surgeons' motivations and perceived needs for leadership knowledge and skills. Themes from interview responses were then used to design the program curriculum specifically to meet the leadership needs of surgical faculty. Three major themes emerged regarding surgeons' motivations for seeking leadership training: (1) Recognizing key gaps in their formal preparation for leadership roles; (2) Exhibiting an appetite for personal self-improvement; and (3) Seeking leadership guidance for career advancement. Participants' interviews revealed four specific domains of knowledge and skills that they indicated as desired takeaways from a LDP: (1) leadership and communication; (2) team building; (3) business acumen/finance; and (4) greater understanding of the health care context. Interviews with surgical faculty members identified gaps in prior leadership training and demonstrated concrete motivations and specific goals for participating in a formal leadership program. A LDP that is specifically tailored to address the needs of surgical faculty may benefit surgeons at a personal and institutional level. Copyright © 2016 Elsevier Inc. All rights reserved.

Insomnia patients' help-seeking experiences.

PubMed

Cheung, Janet M Y; Bartlett, Delwyn J; Armour, Carol L; Glozier, Nicholas; Saini, Bandana

2014-03-04

Timely access to appropriate treatment is important for optimizing insomnia management. To date, little is known about insomnia patients' treatment experiences or how they access and engage with the available health care resources. This study sought to capture the help-seeking experiences and behavioral patterns of patients with insomnia who are seeking or receiving specialist care. A purposive sample of 26 insomnia patients from specialist sleep and mental health clinics located in metropolitan New South Wales, Australia was recruited. Participants completed a brief questionnaire, followed by an in-depth, semi-structured interview. Interviews were digitally recorded, transcribed verbatim, and analyzed using framework analysis. Three key themes emerged from the data: patients' sleep beliefs, treatment beliefs, and accessing specialized care. The findings show that daytime symptoms arising from insomnia serve as important illness cues for patients to seek medical help. In addition, participants' treatment pathways highlight factors that prevent the widespread use of cognitive behavioral therapy for insomnia (CBT-I), including limited awareness about CBT-I, tentative referral mechanisms, limited service providers, and the high cost of CBT-I.

Stigma Experiences in Marginalized People Living With HIV Seeking Health Services and Resources in Canada.

PubMed

Donnelly, Leeann R; Bailey, Lauren; Jessani, Abbas; Postnikoff, Jonathan; Kerston, Paul; Brondani, Mario

HIV stigma may prevent people from obtaining a timely diagnosis and engaging in life-saving care. It may also prevent those who are HIV infected from seeking health and education resources, particularly if they are from marginalized communities. We inductively explored the roots of stigma and its impact on health services and resource seeking as experienced by HIV-infected members of marginalized communities in Vancouver, British Columbia, Canada, using a community-based participatory research framework. Five peer-facilitated focus groups were conducted with 33 Aboriginal, Latino, Asian, and African participants. Thematic analysis of the experiences revealed four dominant themes: beginnings of stigma, tensions related to disclosure, experiences of service seeking, and beyond HIV stigma and discrimination. Persons living with HIV from Aboriginal and refugee communities continue to experience disproportionate rates of stigma and discrimination. Fear remains a prime obstacle influencing these groups' abilities and willingness to access care in various settings. Copyright © 2016 Association of Nurses in AIDS Care. Published by Elsevier Inc. All rights reserved.

The Neutral Islands during the Late Epoch of Reionization

NASA Astrophysics Data System (ADS)

Xu, Yidong; Yue, Bin; Chen, Xuelei

2018-05-01

The large-scale structure of the ionization field during the epoch of reionization (EoR) can be modeled by the excursion set theory. While the growth of ionized regions during the early stage are described by the ``bubble model'', the shrinking process of neutral regions after the percolation of the ionized region calls for an ``island model''. An excursion set based analytical model and a semi-numerical code (islandFAST) have been developed. The ionizing background and the bubbles inside the islands are also included in the treatment. With two kinds of absorbers of ionizing photons, i.e. the large-scale under-dense neutral islands and the small-scale over-dense clumps, the ionizing background are self-consistently evolved in the model.

Mean Energy Density of Photogenerated Magnetic Fields Throughout the EoR

NASA Astrophysics Data System (ADS)

Durrive, Jean-Baptiste; Tashiro, Hiroyuki; Langer, Mathieu; Sugiyama, Naoshi

2018-05-01

There seems to be magnetic fields at all scales and epochs in our Universe, but their origin at large scales remains an important open question of cosmology. In this work we focus on the generation of magnetic fields in the intergalactic medium due to the photoionizations by the first galaxies, all along the Epoch of Reionization. Based on previous studies which considered only isolated sources, we develop an analytical model to estimate the mean magnetic energy density accumulated in the Universe by this process. In our model, without considering any amplification process, the Universe is globally magnetized by this mechanism to the order of, at least, several 10-18 G during the Epoch of Reionization (i.e. a few 10-20 G comoving).

Linking Developmental Themes to Theories in the Autobiographical Narratives of Life-Span Development Students

ERIC Educational Resources Information Center

Mayo, Joseph A.

2017-01-01

Prior research findings point to the efficacy of using autobiographical life-story narration as a learning tool in undergraduate classes. The current study seeks to add to the existing literature on this topic by performing a qualitative analysis across events recorded in students' autobiographical narratives. The purpose of this analysis is to…

Improving University Principal Preparation Programs: Five Themes from the Field

ERIC Educational Resources Information Center

Mendels, Pamela, Ed.

2016-01-01

What is the state of university-based principal preparation programs? How are these essential training grounds of future school leaders viewed--by themselves as well as by the school districts that hire their graduates? Do the programs need to improve? If so, by what means? This publication seeks to help answer those questions by bringing together…

Ohio Geographers: Recent Research Themes. Volume Number 2: 1974.

ERIC Educational Resources Information Center

Roder, Wolf, Ed.; Shelton, Marlyn L., Ed.

Ten professional geography research papers presented at the Geography Section of the 1974 annual meeting of the Ohio Academy of Science are provided. Six of the papers may be considered to fall under the broad classification of human geography, two others are about physical geography, while the remaining two seek to improve the craft of modern…

Faculty Best Practices to Support Students in the "Virtual Doctoral Land"

ERIC Educational Resources Information Center

Deshpande, Anant

2017-01-01

Online students face numerous challenges in successfully completing doctoral programmes. The aim of this article is to explore the best practices that can be employed by faculty to support students in achieving this. It also seeks to categorize and identify the best practices emerging from literature into themes. An exploratory research method was…

Exemplar: A Model for Social Studies Curriculum Development in Delaware, K-12.

ERIC Educational Resources Information Center

Delaware State Dept. of Public Instruction, Dover.

GRADES OR AGES: Grades K-12. SUBJECT MATTER: Social studies. ORGANIZATION AND PHYSICAL APPEARANCE: The subject matter is divided into the following five themes: 1) Man develops within his physical and cultural environment. 2) Man functions within an interdependent society. 3) Man seeks justice and order. 4) Man experiences conflict and change. 5)…

Using Fiction to Teach American History in Middle School: Affects on Student Engagement

ERIC Educational Resources Information Center

Elias, Anjuli Rose

2010-01-01

This research highlights the effects of using literature and relevant curriculum to teach history in grade levels 6 through 8, and analyzes how students respond when learning complicated themes and events through the medium of historic fiction. Specifically, my research seeks to inform secondary educators concerning the use of the narrative and…

At This Time and in This Place: Vocation and Higher Education

ERIC Educational Resources Information Center

Cunningham, David S., Ed.

2015-01-01

Seeking to deepen current scholarly engagement with vocational exploration in both theory and practice, "At This Time and In This Place" champions the themes of calling and vocation as key elements of effective undergraduate education. Growing out of a year-long seminar sponsored by the Council of Independent Colleges and its Network for…

Great Valley Riparian Habitats and the National Registry of Natural Landmarks

Treesearch

Robert F. Holland; Cynthia L. Roye

1989-01-01

The National Registry of Natural Landmarks is a program established by the National Park Service that seeks to recognize nationally significant examples of the Nation's natural history. Nearly 100 Great Valley riparian sites were evaluated using Park Service criteria. Three sites illustrative of the range of this biotic theme were recommended to the National Park...

Valuing autonomy, struggling for an identity and a collective voice, and seeking role recognition: community mental health nurses' perceptions of their roles.

PubMed

White, Jane H; Kudless, Mary

2008-10-01

Leaders in this community mental health system approached the problem of job frustration, morale issues, and turnover concerns of their Community Mental Health Nurses (CMHNs) by designing a qualitative study using Participant Action Research (PAR) methodology based on the philosophy of Habermas. Six focus groups were conducted to address the nurses' concerns. The themes of Valuing Autonomy, Struggling for an Identity and Collective Voice, and Seeking Role Recognition best explained the participants' concerns. The study concluded with an action plan, the implementation of the plan, and a discussion of the plan's final outcomes.

Intrinsic factors influencing help-seeking behaviour in an acute stroke situation.

PubMed

Zock, Elles; Kerkhoff, Henk; Kleyweg, Ruud Peter; van de Beek, Diederik

2016-09-01

The proportion of stroke patients eligible for intravenous or intra-arterial treatment is still limited because many patients do not seek medical help immediately after stroke onset. The aim of our study was to explore which intrinsic factors and considerations influence help-seeking behaviour of relatively healthy participants, confronted with stroke situations. Semi-structured interviews were conducted with 25 non-stroke participants aged 50 years or older. We presented 5 clinical stroke situations as if experienced by the participants themselves. Recognition and interpretation of symptoms were evaluated and various factors influencing help-seeking behaviour were explored in-depth. We used the thematic synthesis method for data analysis. Five themes influencing help-seeking behaviour in a stroke situation were identified: influence of knowledge, views about seriousness, ideas about illness and health, attitudes towards others and beliefs about the emergency medical system. A correct recognition of stroke symptoms or a correct interpretation of the stroke situations did not automatically result in seeking medical help. Interestingly, similar factors could lead to different types of actions between participants. Many intrinsic, as well as social and environmental factors are of influence on help-seeking behaviour in an acute stroke situation. All these factors seem to play a complex role in help-seeking behaviour with considerable inter-individual variations. Accomplishing more patients eligible for acute stroke treatment, future research should focus on better understanding of all factors at various levels grounded in a theory of help-seeking behaviour.

Experiences of experts about the instances of plagiarism.

PubMed

Keyvanara, Mahmod; Ojaghi, Rezvan; Sohrabi, Mozafar Cheshmeh; Papi, Ahmad

2013-01-01

Plagiarism is defined as intentional deceiving or lack of honesty, which deprives others from both material and spiritual possessions. Ethics is considered as one of the most important aspects of evaluating the quality of higher education. Moreover, scientific ethics should be reflected from university values, as a specialized institution, rather than being a reflection of the others cares. Therefore, the main aim of the present study is explore of expert experiences about plagiarism in Isfahan University of Medical Sciences. This study employed qualitative method with using in-deep interview. The research participants consisted of 21, who tend to this work. Semi structure interview were conducted and recorded. The method of analyzing data was 'thematic analysis'. The data were transcribed and saved on computer after each interview. Themes and sub-themes were extracted. Finally, relevant sub-themes were arranged in a category and suggested were presented. Analyzing data showed 600 primary codes, 40 sub-themes and 6 themes. The main themes included repeated works, non-normative adoption, non-normative adaptation, shares distribution, forging, and profit-seeking, each of which consisted of one or several subgroups. The findings of this study show that since, there are numerous ways of cheating, the universities' research committees must create institutions in order to educate the individuals how to avoid plagiarism. In addition, providing information about different types of scientific violations, as well as their following punishments might lead to the decrease of such misbehaviors.

Promoting and Protecting Against Stigma in Assisted Living and Nursing Homes.

PubMed

Zimmerman, Sheryl; Dobbs, Debra; Roth, Erin G; Goldman, Susan; Peeples, Amanda D; Wallace, Brandy

2016-06-01

To determine the extent to which structures and processes of care in multilevel settings (independent living, assisted living, and nursing homes) result in stigma in assisted living and nursing homes. Ethnographic in-depth interviews were conducted in 5 multilevel settings with 256 residents, families, and staff members. Qualitative analyses identified the themes that resulted when examining text describing either structures of care or processes of care in relation to 7 codes associated with stigma. Four themes related to structures of care and stigma were identified, including the physical environment, case mix, staff training, and multilevel settings; five themes related to processes of care and stigma, including dining, independence, respect, privacy, and care provision. For each theme, examples were identified illustrating how structures and processes of care can potentially promote or protect against stigma. In no instance were examples or themes identified that suggested the staff intentionally promoted stigma; on the other hand, there was indication that some structures and processes were intentionally in place to protect against stigma. Perhaps the most important theme is the stigma related to multilevel settings, as it has the potential to reduce individuals' likelihood to seek and accept necessary care. Results suggest specific recommendations to modify care and reduce stigma. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Silence of male child sexual abuse in India: Qualitative analysis of barriers for seeking psychiatric help in a multidisciplinary unit in a general hospital

PubMed Central

Subramaniyan, Vyjayanthi Kanugodu Srinivasa; Reddy, Praveen; Chandra, Girish; Rao, Chandrika; Rao, T. S. Sathyanarayana

2017-01-01

Introduction: In 2007, Ministry of Women and Child Welfare, supported by United Nations Children's Fund, save the children and Prayas conducted a study to understand the magnitude of child abuse in India, they found that 53.22% children faced one or more forms of sexual abuse; among them, the number of boys abused was 52.94%. Aim: The aim of this study was to explore the barriers for seeking psychiatric help by qualitative analysis of stake holders of male victims of child abuse. Materials and Methods: All the statements made by the stakeholders regarding psychiatric assessment and treatment were recorded in each referral made to the psychiatrist. Semistructured interviews and in-depth interviews were conducted to explore the topic of understanding the need for psychiatric treatment to the victims. Results: Collaborative child response unit, a multidisciplinary team, to tackle child sexual abuse in a general hospital received three referrals of male child abuse among the 27 referrals in 20 months. The main theme of the barrier that was generated by interviewing the stakeholders of male child victims of abuse was the misconception of superiority of a male victim due to gender (patriarchy) an expectation that he will outgrow the experience. In-depth interviews of three cases of homosexual abuse explored the theme. Conclusion: Patriarchy is oppressing male children and acts as a barrier to seek psychiatric help in collaborative child response unit. PMID:28827868

Numerical Radiative Transfer and the Hydrogen Reionization of the Universe

NASA Astrophysics Data System (ADS)

Petkova, M.

2011-03-01

One of the most interesting questions in cosmology is to understand how the Universe evolved from its nearly uniform and simple state briefly after the Big Bang to the complex state we see around us today. In particular, we would like to explain how galaxies have formed, and why they have the properties that we observe in the local Universe. Computer simulations play a highly important role in studying these questions, because they allow one to follow the dynamical equations of gravity and hydrodynamics well into the non-linear regime of the growth of cosmic structures. The current generation of simulation codes for cosmological structure formation calculates the self-gravity of dark matter and cosmic gas, and the fluid dynamics of the cosmic gas, but radiation processes are typically not taken into account, or only at the level of a spatially uniform, externally imposed background field. However, we know that the radiation field has been highly inhomogeneous during certain phases of the growth of structure, and may have in fact provided important feedback effects for galaxy formation. In particular, it is well established that the diffuse gas in the universe was nearly fully neutral after recombination at very high redshift, but today this gas is highly ionized. Sometime during the evolution, a transition to the ionized state must have occurred, a process we refer to as reionization. The UV radiation responsible for this reionization is now permeating the universe and may in part explain why small dwarf galaxies have so low luminosities. It is therefore clear that accurate and self-consistent studies of galaxy formation and of the dynamics of the reionization process should ideally be done with simulation codes that directly include a treatment of radiative transfer, and that account for all relevant source and sink terms of the radiation. We present a novel numerical implementation of radiative transfer in the cosmological smoothed particle hydrodynamics (SPH) simulation code GADGET. It is based on a fast, robust and photon-conserving integration scheme where the radiation transport problem is approximated in terms of moments of the transfer equation and by using a variable Eddington tensor as a closure relation, following the "OTVET"-suggestion of Gnedin & Abel. We derive a suitable anisotropic diffusion operator for use in the SPH discretization of the local photon transport, and we combine this with an implicit solver that guarantees robustness and photon conservation. This entails a matrix inversion problem of a huge, sparsely populated matrix that is distributed in memory in our parallel code. We solve this task iteratively with a conjugate gradient scheme. Finally, to model photon sink processes we consider ionization and recombination processes of hydrogen, which is represented with a chemical network that is evolved with an implicit time integration scheme. We present several tests of our implementation, including single and multiple sources in static uniform density fields with and without temperature evolution, shadowing by a dense clump, and multiple sources in a static cosmological density field. All tests agree quite well with analytical computations or with predictions from other radiative transfer codes, except for shadowing. However, unlike most other radiative transfer codes presently in use for studying reionization, our new method can be used on-the-fly during dynamical cosmological simulations, allowing simultaneous treatments of galaxy formation and the reionization process of the Universe. We carry out hydrodynamical simulations of galaxy formation that simultaneously follow radiative transfer of hydrogen-ionizing photons, based on the optically-thin variable Eddington tensor approximation as implemented in the GADGET code. We consider only star-forming galaxies as sources and examine to what extent they can yield a reasonable reionization history and thermal state of the intergalactic medium at redshifts around z~3. This serves as an important benchmark for our self-consistent methodology to simulate galaxy formation and reionization, and for future improvements through accounting of other sources and other wavelength ranges. We find that star formation alone is sufficient for rinsing the Universe by redshift z~6. For a suitable choice of the escape fraction and the heating efficiency, our models are approximately able to account at the same time for the one-point function and the power spectrum of the Lyman-Forest. The radiation field has an important impact on the star formation rate density in our simulations and significantly lowers the gaseous and stellar fractions in low-mass dark matter halos. Our results thus directly demonstrate the importance of radiative feedback for galaxy formation. In search for even better and more accurate methods we introduce a numerical implementation of radiative transfer based on an explicitly photon conserving advection scheme, where radiative fluxes over the cell interfaces of a structured or unstructured mesh are calculated with a second-order reconstruction of the intensity field. The approach employs a direct discretization of the radiative transfer equation in Boltzmann form with adjustable angular resolution that in principle works equally well in the optically thin and optically thick regimes. In our most general formulation of the scheme, the local radiation field is decomposed into a linear sum of directional bins of equal solid-angle, tessellating the unit sphere. Each of these "cone-fields" is transported independently, with constant intensity as a function of direction within the cone. Photons propagate at the speed of light (or optionally using a reduced speed of light approximation to allow larger timesteps), yielding a fully time-dependent solution of the radiative transfer equation that can naturally cope with an arbitrary number of sources, as well as with scattering. The method casts sharp shadows, subject to the limitations induced by the adopted angular resolution. If the number of point sources is small and scattering is unimportant, our implementation can alternatively treat each source exactly in angular space, producing shadows whose sharpness is only limited by the grid resolution. A third hybrid alternative is to treat only a small number of the locally most luminous point sources explicitly, with the rest of the radiation intensity followed in a radiative diffusion approximation. We have implemented the method in the moving-mesh code AREPO, where it is coupled to the hydrodynamics in an operator splitting approach that subcycles the radiative transfer alternatingly with the hydrodynamical evolution steps. We also discuss our treatment of basic photon sink processes relevant for cosmological reionization, with a chemical network that can accurately deal with non-equilibrium effects. We discuss several tests of the new method, including shadowing configurations in two and three dimensions, ionized sphere expansion in static and dynamic density field and the ionization of a cosmological density field. The tests agree favorably with analytic expectations and results based on other numerical radiative transfer approximations. We compare how our schemes perform in a simulation of hydrogen reionization, excluding stellar winds due to development issues. The underlying cosmological simulation codes produce different star formation rate histories, which results in a different total photon budget. As a consequence reionization in GADGET happens at a higher redshift, i.e. sooner, than in AREPO. The lower number of ionizing photons in the latter code results in a higher volume-averaged neutral fraction at redshift z = 3 and a different temperature state of the baryonic gas. We find that in both reionization scenarios the baryon fraction of low mass dark matter halos is reduced due to photoheating processes and observe that the change is bigger in the GADGET simulation than in the AREPO one, which is due to the higher ionized fractions we find the in former. Both simulations compare marginally well with the Lyman-poorest observations at redshift z = 3, but results are not expected to be in very good agr! eement due the lack of the essential feedback from stellar winds in the simulations. Finally, we can conclude that despite the differences between the two realizations, both codes perform well at the given problem and are suitable for studying the process of reionization because they produce sensible results in the limits of observations. We emphasize that the reionization history depends strongly on the star formation rate density in the simulations and which should therefore be accurately reproduced.

Postpartum depression among African-American women.

PubMed

Amankwaa, Linda Clark

2003-01-01

The purpose of this qualitative study was to describe the nature of postpartum depression (PPD) among African-American women. Twelve women, who had experienced PPD within the last three years, were interviewed for approximately one hour at two intervals. Nudist-4 software and the constant comparative method were used to analyze the data. Five themes "Stressing Out," "Feeling Down," "Losing It," "Seeking Help," and "Feeling Better" represented aspects of PPD as experienced by the participants. The last theme, "Dealing with It," represented the cultural ways in which African-American mothers managed their depression. These included Keeping the Faith, Trying to Be a Strong Black Woman, Living with Myths, and Keeping Secrets. Suggestions for future directions in nursing research are included.

Acceptance of spousal death: the factor of time in bereaved older adults' search for meaning.

PubMed

Chan, Wallace Chi Ho; Chan, Cecilia L W

2011-02-01

Response to the death of a spouse was examined by focusing on acceptance, which was conceptualized as both a process and an outcome. Grounded theory was applied to analyze the experience of 15 bereaved Hong Kong Chinese older adults. The main theme that emerged was time. Acceptance of spousal death was found to be related to the search for meaning in 2 time-related themes: timing of spousal death and paradoxical time perception. For paradoxical time perception, 2 subthemes were identified: truncation and daily isolation in time. For bereaved older adults, time-related meaning seeking may be best fostered by self-transcendence, (e.g., participation in volunteer work and social activities).

Can Low-Luminosity Galaxies Reionize the Universe?

NASA Astrophysics Data System (ADS)

Ferguson, Harry

2017-08-01

The prevailing wisdom is that low-luminosity galaxies are responsible for cosmic reionization. If this is true, then low-luminosity galaxies at high redshift have to be different from most of the low-luminosity galaxies studied to date at low redshift, which absorb too much of their ionizing radiation. While it is possible that high-z dwarf galaxies have the same metallicity at fixed mass and star-formation rate as low-redshift galaxies, they are different in one key respect. At fixed dark-halo mass, they are probably much denser (having collapsed earlier). This could lead to higher star-formation surface densities more capable of creating cavities in the ISM. But the denser halos of surrounding gas could be harder to clear. There is a critical need for further observations to validate and test physical models for the trends of escaping ionizing continuum with redshift, luminosity, and surface density. JWST will not be able to measure ionizing radiation during the epoch of reionization because the IGM absorbs most of the photons. To prepare for JWST, we need to use the ultraviolet capabilities of HST to measure diverse samples of galaxies at z<3, where we can see the photons and quantify the trends with other galaxy properties. As a complement to other studies, we propose to constrain the Lyman-continuum emission from 8 relatively low-luminosity strongly-lensed galaxies at 1

The Cosmology Large Angular Scale Surveyor

NASA Astrophysics Data System (ADS)

Harrington, Kathleen; Marriage, Tobias; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe; Dahal, Sumit; Denis, Kevin; Dünner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Fluxa, Pedro; Halpern, Mark; Hilton, Gene; Hinshaw, Gary F.; Hubmayr, Johannes; Iuliano, Jeffrey; Karakla, John; McMahon, Jeff; Miller, Nathan T.; Moseley, Samuel H.; Palma, Gonzalo; Parker, Lucas; Petroff, Matthew; Pradenas, Bastián.; Rostem, Karwan; Sagliocca, Marco; Valle, Deniz; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

2016-07-01

The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).

The Hydrogen Epoch of Reionization Array Dish. I. Beam Pattern Measurements and Science Implications

NASA Astrophysics Data System (ADS)

Neben, Abraham R.; Bradley, Richard F.; Hewitt, Jacqueline N.; DeBoer, David R.; Parsons, Aaron R.; Aguirre, James E.; Ali, Zaki S.; Cheng, Carina; Ewall-Wice, Aaron; Patra, Nipanjana; Thyagarajan, Nithyanandan; Bowman, Judd; Dickenson, Roger; Dillon, Joshua S.; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Jacobs, Daniel C.; Kohn, Saul A.; Klima, Patricia J.; Moodley, Kavilan; Saliwanchik, Benjamin R. B.; Schaffner, Patrick; Shelton, John; Taylor, H. A.; Taylor, Rusty; Tegmark, Max; Wirt, Butch; Zheng, Haoxuan

2016-08-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. In this paper, we focus on the angular response (I.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m2 in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ˜ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.

The Cosmology Large Angular Scale Surveyor (CLASS)

NASA Technical Reports Server (NTRS)

Harrington, Kathleen; Marriange, Tobias; Aamir, Ali; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe;

THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. I. BEAM PATTERN MEASUREMENTS AND SCIENCE IMPLICATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neben, Abraham R.; Hewitt, Jacqueline N.; Ewall-Wice, Aaron

2016-08-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish withmore » simulations and measurements. In this paper, we focus on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m{sup 2} in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ∼ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.« less

Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sathyanarayana Rao, Mayuri; Subrahmanyan, Ravi; Shankar, N Udaya

Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30–6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal.more » We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes’ integration.« less

LOW-MASS SUPPRESSION OF THE SATELLITE LUMINOSITY FUNCTION DUE TO THE SUPERSONIC BARYON-COLD-DARK-MATTER RELATIVE VELOCITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bovy, Jo; Dvorkin, Cora

We study the effect of the supersonic baryon-cold-dark-matter (CDM) flow, which has recently been shown to have a large effect on structure formation during the dark ages 10 {approx}< z {approx}< 1000, on the abundance of luminous, low-mass satellite galaxies around galaxies like the Milky Way. As the supersonic baryon-CDM flow significantly suppresses both the number of halos formed and the amount of baryons accreted onto such halos of masses 10{sup 6} < M{sub halo}/M{sub Sun} < 10{sup 8} at z {approx}> 10, a large effect results on the stellar luminosity function before reionization. As halos of these masses aremore » believed to have very little star formation after reionization due to the effects of photoheating by the ultraviolet background, this effect persists to the present day. We calculate that the number of low-mass 10{sup 6} < M{sub halo}/M{sub Sun} < 5 Multiplication-Sign 10{sup 7} halos that host luminous satellite galaxies today is typically suppressed by 50%, with values ranging up to 90% in regions where the initial supersonic velocity is high. We show that this previously ignored cosmological effect resolves some of the tension between the observed and predicted number of low-mass satellites in the Milky Way, reducing the need for other mass-dependent star-formation suppression before reionization.« less

Film in the College Classroom: Using "Twilight" to Examine Adolescent Development

ERIC Educational Resources Information Center

Tagsold, Jennifer T.; Decuir-Gunby, Jessica

2012-01-01

The hit movie saga "Twilight" has made an impact on viewers of all ages. This article seeks to explore the uses of film in psychology classes with a focus on ways in which instructors may find scenes from the "Twilight" series helpful and engaging for students. The authors describe scenes and themes from the first three movies…

Defining Fun and Seeking Flow in English Language Arts

ERIC Educational Resources Information Center

Romano, Tom

2009-01-01

Students have fun with Facebook, MySpace, YouTube, and video games. They have fun text messaging, talking on cell phones, listening to iPods. They have fun at theme parks and hanging out with friends. As their teacher the author wants to introduce students to another kind of fun. This fun can be time consuming, rigorous, and fulfilling. It's the…

Australia seeks free science debate

NASA Astrophysics Data System (ADS)

Pockley, Peter

2008-04-01

A major theme of the Australian election last November was the conflicting views of the competing parties on climate change. The former Conservative government under Prime Minister John Howard stuck to its refusal, alone with US President George Bush, to ratify the Kyoto accord. However, it was heavily criticized for suppressing the evidence for global warming from scientists who were dependent on government support.

Seeking Refuge in Literacy from a Scorpion Bite

ERIC Educational Resources Information Center

Sarroub, Loukia K.

2007-01-01

The purpose of this study is to examine a refugee boy's experiences with literacy in and out of school in the US. Within these contexts, I explore this youth's literacy development in light of his identity as a poor Yezidi Kurdish refugee from Iraq. Central to the article are two main themes. The first, life as a scorpion sting, explicates the…

Next Generation Communications: Making IT Work. Pacific Telecommunications Council Annual Conference Proceedings (24th, Honolulu, Hawaii, January 13-17, 2002).

ERIC Educational Resources Information Center

Pacific Telecommunications Council, Honolulu, HI.

This proceedings includes the papers presented at the 2002 conference of the Pacific Telecommunications Council (PTC), with its theme "Next Generation Communications: Making IT Work." The PTC2002 annual conference seeks to focus on harnessing the complexities of the broadest range of communications technologies and services for the user.…

Invited Review: Challenges of Residential and Community Care--"The Times They Are a-Changin"

ERIC Educational Resources Information Center

Jackson, R.

2011-01-01

This paper seeks to examine a number of issues which relate to the provision of appropriate and high-quality residential and community care for people with an intellectual disability. A number of key themes emerging from this Special Issue of the "Journal of Intellectual Disability Research" are identified and explored: (1) normalisation; (2)…

Stress Management among Parents of Neonates Hospitalized in NICU: A Qualitative Study.

PubMed

Heidari, Haydeh; Hasanpour, Marzieh; Fooladi, Marjan

2017-03-01

Introduction: Infant hospitalization is stressful event for parent in NICU. Parents think that they have lost control because of unfamiliar environment. Therefore, stress management is very important in this period. The family as the main factor of strength and protection for infant is required as the bases of standard care in NICU. Therefore the aim of this study was to investigate stress management in Iranian NICU Parents. Methods: Using qualitative content analysis approach helped to collect and analysis data for open coding, classification, and theme abstraction. Twenty one parents with hospitalized neonates, physicians and nurses in the city of Isfahan were purposely recruited and selected for in-depth interviews. Results: The analyzed content revealed unique stress management approaches among the parents. The main themes were: 1) spirituality, 2) seeking information, 3) Seeking hope, 4) maintaining calm, 5) attachment to infant, and 6) communicating with the medical team Conclusion: Findings of this study highlights the importance of medical team's attention to stressed parents who are trying to make adjustment or adapt to the hospitalization of their infant. A revised management approach to address the emotional needs of parents of neonates in Iran seems essential for improving communication with physicians and nurses.

Autism Narratives in Media Coverage of the MMR Vaccine-Autism Controversy under a Crip Futurism Framework.

PubMed

Mann, Benjamin W

2018-03-09

While previous studies in health communication have examined online news media regarding autism, there is a lack of research that critically examines how such media representations may stigmatize autism and seeks to eliminate the condition, particularly in the context of the resurging measles, mumps, and rubella (MMR) vaccine-autism controversy. To address this gap in the literature, this study analyzes 153 articles that engage the MMR vaccine-autism controversy from the top 10 online news sources in the U.S. from September 2015 through July 2017. It draws from Kafer's (2013) work in Feminist, Crip, Queer, using a lens of crip futurism to interpret three major narrative themes: a death and survival narrative that purports autism as a worst-case scenario, a societal problem narrative, and a preventative narrative that seeks to eliminate the condition. These themes suggest that online news media narratives about autism surrounding the autism-MMR controversy play into stereotypes about autism, including stigmatization and prioritization of preventive behaviors and cures over supporting the lived experiences of autistic individuals. Continued research on the impact of online media portrayals of autism specifically, and disability in health contexts generally, is called for.

Stress Management among Parents of Neonates Hospitalized in NICU: A Qualitative Study

PubMed Central

Heidari, Haydeh; Hasanpour, Marzieh; Fooladi, Marjan

2017-01-01

Introduction: Infant hospitalization is stressful event for parent in NICU. Parents think that they have lost control because of unfamiliar environment. Therefore, stress management is very important in this period. The family as the main factor of strength and protection for infant is required as the bases of standard care in NICU. Therefore the aim of this study was to investigate stress management in Iranian NICU Parents. Methods: Using qualitative content analysis approach helped to collect and analysis data for open coding, classification, and theme abstraction. Twenty one parents with hospitalized neonates, physicians and nurses in the city of Isfahan were purposely recruited and selected for in-depth interviews. Results: The analyzed content revealed unique stress management approaches among the parents. The main themes were: 1) spirituality, 2) seeking information, 3) Seeking hope, 4) maintaining calm, 5) attachment to infant, and 6) communicating with the medical team Conclusion: Findings of this study highlights the importance of medical team’s attention to stressed parents who are trying to make adjustment or adapt to the hospitalization of their infant. A revised management approach to address the emotional needs of parents of neonates in Iran seems essential for improving communication with physicians and nurses. PMID:28299295

Ultraviolet luminosity density of the universe during the epoch of reionization

PubMed Central

Mitchell-Wynne, Ketron; Cooray, Asantha; Gong, Yan; Ashby, Matthew; Dolch, Timothy; Ferguson, Henry; Finkelstein, Steven; Grogin, Norman; Kocevski, Dale; Koekemoer, Anton; Primack, Joel; Smidt, Joseph

2015-01-01

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be . This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys. PMID:26348033

Search for Efficient Foreground Subtraction Method in 21cm Cosmology

NASA Astrophysics Data System (ADS)

Datta, Abhirup; Choudhury, Madhurima; Chakraborty, Arnab

2017-06-01

Observations of the HI 21 cm transition line promises to be an important probe into the cosmic Dark Ages and Epoch of Reionization. Detection of this redshifted 21 cm signal is one of the key science goal for several upcoming and future low frequency radio telescopes like Hydrogen Epoch of Reionization Array (HERA), Square Kilometer Array (SKA) and Dark Ages Radio Explorer (DARE). One of the challenges for the detection of this signal is the accuracy of the foreground source removal. Several novel techniques have been explored already to remove bright foregrounds from both interferometric as well as total power experiments. Here, we present preliminary results from our investigation on application of Artificial Neural Networks to detect faint 21cm global signal amidst the sea of bright galactic foreground.

Dipole of the Epoch of reionization 21-cm signal

DOE PAGES

Slosar, Anze

2017-04-10

The motion of the Solar System with respect to the cosmic rest frame modulates the monopole of the epoch of reionization 21-cm signal into a dipole. This dipole has a characteristic frequency dependence that is dominated by the frequency derivative of the monopole signal. We argue that although the signal is weaker by a factor of ~100, there are significant benefits in measuring the dipole. Most importantly, the direction of the cosmic velocity vector is known exquisitely well from the cosmic microwave background and is not aligned with the galaxy velocity vector that modulates the foreground monopole. Furthermore, an experimentmore » designed to measure a dipole can rely on differencing patches of the sky rather than making an absolute signal measurement, which helps with some systematic effects.« less

Ultraviolet luminosity density of the universe during the epoch of reionization

NASA Astrophysics Data System (ADS)

Mitchell-Wynne, Ketron; Cooray, Asantha; Gong, Yan; Ashby, Matthew; Dolch, Timothy; Ferguson, Henry; Finkelstein, Steven; Grogin, Norman; Kocevski, Dale; Koekemoer, Anton; Primack, Joel; Smidt, Joseph

2015-09-01

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be . This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys.

Beyond CMB cosmic variance limits on reionization with the polarized Sunyaev-Zel'dovich effect

NASA Astrophysics Data System (ADS)

Meyers, Joel; Meerburg, P. Daniel; van Engelen, Alexander; Battaglia, Nicholas

2018-05-01

Upcoming cosmic microwave background (CMB) surveys will soon make the first detection of the polarized Sunyaev-Zel'dovich effect, the linear polarization generated by the scattering of CMB photons on the free electrons present in collapsed objects. Measurement of this polarization along with knowledge of the electron density of the objects allows a determination of the quadrupolar temperature anisotropy of the CMB as viewed from the space-time location of the objects. Maps of these remote temperature quadrupoles have several cosmological applications. Here we propose a new application: the reconstruction of the cosmological reionization history. We show that with quadrupole measurements out to redshift 3, constraints on the mean optical depth can be improved by an order of magnitude beyond the CMB cosmic variance limit.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Qing-Guo; Wang, Ke, E-mail: huangqg@itp.ac.cn, E-mail: wangke@itp.ac.cn

The early reionization (ERE) is supposed to be a physical process which happens after recombination, but before the instantaneous reionization caused by the first generation of stars. We investigate the effect of the ERE on the temperature and polarization power spectra of cosmic microwave background (CMB), and adopt principal components analysis (PCA) to model-independently reconstruct the ionization history during the ERE. In addition, we also discuss how the ERE affects the cosmological parameter estimates, and find that the ERE does not impose any significant influences on the tensor-to-scalar ratio r and the neutrino mass at the sensitivities of current experiments.more » The better CMB polarization data can be used to give a tighter constraint on the ERE and might be important for more precisely constraining cosmological parameters in the future.« less

The variance of dispersion measure of high-redshift transient objects as a probe of ionized bubble size during reionization

NASA Astrophysics Data System (ADS)

Yoshiura, Shintaro; Takahashi, Keitaro

2018-01-01

The dispersion measure (DM) of high-redshift (z ≳ 6) transient objects such as fast radio bursts can be a powerful tool to probe the intergalactic medium during the Epoch of Reionization. In this paper, we study the variance of the DMs of objects with the same redshift as a potential probe of the size distribution of ionized bubbles. We calculate the DM variance with a simple model with randomly distributed spherical bubbles. It is found that the DM variance reflects the characteristics of the probability distribution of the bubble size. We find that the variance can be measured precisely enough to obtain the information on the typical size with a few hundred sources at a single redshift.

Reionization in a cold dark matter universe: The feedback of galaxy formation on the intergalactic medium

NASA Technical Reports Server (NTRS)

Shapiro, Paul R.; Giroux, Mark L.; Babul, Arif

1994-01-01

We study the coupled evolution of the intergalactic medium (IGM) and the emerging structure in the universe in the context of the cold dark matter (CDM) model, with a special focus on the consequences of imposing reionization and the Gunn-Peterson constraint as a boundary condition on the model. We have calculated the time-varying density of the IGM by coupling our detailed, numerical calculations of the thermal and ionization balance and radiative transfer in a uniform, spatially averaged IGM of H and He, including the mean opacity of an evolving distribution of gas clumps which correspond to quasar absorption line clouds, to the linearized equations for the growth of density fluctuations in both the gaseous and dark matter components in a CDM universe. We use the linear growth equations to identify the fraction of the gas which must have collapsed out at each epoch, an approach similar in spirit to the so-called Press-Schechter formalism. We identify the IGM density with the uncollapsed baryon fraction. The collapsed fraction is postulated to be a source of energy injection into the IGM, by radiation or bulk hydrodynamical heating (e.g., via shocks) or both, at a rate which is marginally enough to satisfy the Gunn-Peterson constraint at z less than 5. Our results include the following: (1) We find that the IGM in a CDM model must have contained a substantial fraction of the total baryon density of the universe both during and after its reionization epoch. (2) As a result, our previous conclusion that the observed Quasi-Stellar Objects (QSOs) at high redshift are not sufficient to ionize the IGM enough to satisfy the Gunn-Peterson constraint is confirmed. (3) We predict a detectable He II Gunn-Peterson effect at 304(1 + z) A in the spectra of quasars at a range of redshift z greater than or approx. 3, depending on the nature of the sources of IGM reionization. (4) We find, moreover, that a CDM model with high bias parameter b (i.e., b greater than or approx. 2) cannot account for the baryon content of the universe at z approximately 3 observed in quasar absorption line gas unless Omega (sub B) significantly exceeds the maximum value allowed by big bang nucleocynthesis. (5) For a CDM model with bias parameter within the allowed range of (lower) values, the lower limit to Omega(sub B) imposed by big bang nucleosynthesis (Omega(sub B) h(sup 2) greater than or equal to 0.01) combines with our results to yield the minimum IGM density for the CDM fodel. For CDM with b = 1 (Cosmic Background Explorer (COBE) normalization), we find Omega(sub IGM)(sup min) (z approximately 4) approx. equal 0.02-0.03, and Omega(sub IGM)(sup min)(z approximately 0) approx. equal 0.005-0.03, depending upon the nature of the sources of IGM reionization. (6) In general, we find that self-consistent reionization of the IGM by the collapsed baryon fraction has a strong effect on the rate of collapse. (7) As a further example, we show that the feedback effect on the IGM of energy release by the collapsed baryon fraction may explain the slow evolution of the observed comoving QSO number density between z = 5 and z = 2, followed by the sharp decline after z = 2.

Desistance and Treatment Seeking Among Women With Substance Use Disorders.

PubMed

Rhodes, Blythe E; Gottfredson, Nisha C; Hill, Lauren M

2018-04-01

Addiction rates are rising faster among women than men. However, women with substance use disorders are less likely to enter treatment than males. This study seeks to understand how turning-point events and other maturational processes affect "life course persistent" women's motivations for seeking treatment for their disorder. We conducted semi-structured in-depth interviews with 30 women who were receiving treatment for addiction using thematic analysis. Recurring themes were as follows: experiences of rock-bottom events prior to entering treatment, feeling "sick and tired" in regard to both their physical and mental health, and shifting identities or perceptions of themselves. We discuss the importance of motivating shifts in identity to prevent women from entering treatment as a result of more traumatic mechanisms as well as the possibility of intercepting women with substance dependence and chronic health conditions in primary care or hospital settings with the aim of encouraging treatment.

Why people seek advice from community pharmacies about skin problems.

PubMed

Tucker, Rod; Stewart, Derek

2015-04-01

The objective of this study was to explore the reasons why patients with undiagnosed skin problems seek advice at pharmacies. Semi-structured telephone interviews were conducted with patients presenting at pharmacies requesting advice for their own (or their child's) undiagnosed skin problem. Twenty-five patients were interviewed. Key themes around choice of pharmacy were convenience of professional advice, triage to general practitioner (GP) care if warranted, inaccessibility of GP care and perceived non-serious nature of the condition. Interviewees also described high levels of trust in their pharmacists. Few concerns were noted, but those that were centred on lack of privacy and the potential for misdiagnosis. Almost all participants felt positive about their pharmacy care and would re-visit for future skin problems. Patients with undiagnosed skin problems seek advice from pharmacies for reasons of professional advice, accessibility, familiarity and trust and because they perceive their conditions as non-serious. © 2014 Royal Pharmaceutical Society.

Foucault on targets.

PubMed

Lynch, John

2004-01-01

This paper seeks to gain an insight into the behavior of a large NHS trust, in its attempt to meet a 90 percent patient access target, in a week long national audit in March 2003. Why did individuals act in dramatically different ways to their norm over this period. The work of Michel Foucault is used to explore these issues. The discourses of power, knowledge, discipline and governmentality are identified as key foucaudian themes that offer an alternative interpretation of how individuals behave in their place of work. The importance of the historical context of discourse within the NHS cannot be underestimated in shaping the behavior of individuals and groups today. Power and knowledge permeate NHS organizations through disciplinary practices and dressage. Governmentality seeks to maintain the status quo through disciplinary processes such as national healthcare targets. The natural response of NHS organizations is therefore, to seek order and conformity rather than disorder and conflict.

Medical Anthropology in Africa: The Trouble with a Single Story.

PubMed

Mkhwanazi, Nolwazi

2016-01-01

In the growing number of publications in medical anthropology about sub-Saharan Africa, there is a tendency to tell a single story of medicine, health, and health-seeking behavior. The heavy reliance on telling this singular story means that there is very little exposure to other stories. In this article, I draw on five books published in the past five years to illustrate the various components that make up this dominant narrative. I then provide examples of two accounts about medicine, health, and health-seeking behavior in Africa that deviate from this dominant narrative, in order to show the themes that alternative accounts have foregrounded. Ultimately, I make a plea to medical anthropologists to be mindful of the existence of this singular story and to resist the tendency to use its components as scaffolding in their accounts of medicine, health, and health-seeking behavior in Africa.

The Transient High Energy Sky and Early Universe Surveyor

NASA Astrophysics Data System (ADS)

O'Brien, P. T.

2016-04-01

The Transient High Energy Sky and Early Universe Surveyor is a mission which will be proposed for the ESA M5 call. THESEUS will address multiple components in the Early Universe ESA Cosmic Vision theme:4.1 Early Universe,4.2 The Universe taking shape, and4.3 The evolving violent Universe.THESEUS aims at vastly increasing the discovery space of the high energy transient phenomena over the entire cosmic history. This is achieved via a unique payload providing an unprecedented combination of: (i) wide and deep sky monitoring in a broad energy band(0.3 keV-20 MeV; (ii) focusing capabilities in the soft X-ray band granting large grasp and high angular resolution; and (iii) on board near-IR capabilities for immediate transient identification and first redshift estimate.The THESEUS payload consists of: (i) the Soft X--ray Imager (SXI), a set of Lobster Eye (0.3--6 keV) telescopes with CCD detectors covering a total FOV of 1 sr; (ii) the X--Gamma-rays spectrometer (XGS), a non-imaging spectrometer (XGS) based on SDD+CsI, covering the same FOV than the Lobster telescope extending the THESEUS energy band up to 20 MeV; and (iii) a 70cm class InfraRed Telescope (IRT) observing up to 2 microns with imaging and moderate spectral capabilities.The main scientific goals of THESEUS are to:(a) Explore the Early Universe (cosmic dawn and reionization era) by unveiling the Gamma--Ray Burst (GRBs) population in the first billion years}, determining when did the first stars form, and investigating the re-ionization epoch, the interstellar medium (ISM) and the intergalactic medium (IGM) at high redshifts.(b) Perform an unprecedented deep survey of the soft X-ray transient Universe in order to fill the present gap in the discovery space of new classes of transient; provide a fundamental step forward in the comprehension of the physics of various classes of Galactic and extra--Galactic transients, and provide real time trigger and accurate locations of transients for follow-up with next-generation facilities.(c) Provide IR survey capabilities in space and strong guest observer possibilities, thus allowing a strong community involvement. All transient alerts will be public.

Assembling the Infrared Extragalactic Background Light with CIBER-2: Probing Inter-Halo Light and the Epoch of Reionization.

NASA Astrophysics Data System (ADS)

Bock, James

We propose to carry out a program of observations with the Cosmic Infrared Background Experiment (CIBER-2). CIBER-2 is a near-infrared sounding rocket experiment designed to measure spatial fluctuations in the extragalactic background light. CIBER-2 scientifically follows on the detection of fluctuations with the CIBER-1 imaging instrument, and will use measurement techniques developed and successfully demonstrated by CIBER-1. With high-sensitivity, multi-band imaging measurements, CIBER-2 will elucidate the history of interhalo light (IHL) production and carry out a deep search for extragalactic background fluctuations associated with the epoch of reionization (EOR). CIBER-1 has made high-quality detections of large-scale fluctuations over 4 sounding rocket flights. CIBER-1 measured the amplitude and spatial power spectrum of fluctuations, and observed an electromagnetic spectrum that is close to Rayleigh-Jeans, but with a statistically significant turnover at 1.1 um. The fluctuations cross-correlate with Spitzer images and are significantly bluer than the spectrum of the integrated background derived from galaxy counts. We interpret the CIBER-1 fluctuations as arising from IHL, low-mass stars tidally stripped from their parent galaxies during galaxy mergers. The first generation of stars and their remnants are likely responsible for the for the reionization of the intergalactic medium, observed to be ionized out to the most distant quasars at a redshift of 6. The total luminosity produced by first stars is uncertain, but a lower limit can be placed assuming a minimal number of photons to produce and sustain reionization. This 'minimal' extragalactic background component associated with reionization is detectable in fluctuations at the design sensitivity of CIBER-2. The CIBER-2 instrument is optimized for sensitivity to surface brightness in a short sounding rocket flight. The instrument consists of a 28 cm wide-field telescope operating in 6 spectral bands between 0.5 and 2.0 um, cooled to a temperature of 77 K with a liquid nitrogen cryostat. Images are composed using 3 focal plane assemblies operating H2RG detector arrays. The instrument is currently being fabricated with expected delivery during summer 2014, and will be ready for its first flight in 2015. CIBER-2 will extend the CIBER-1 observations from the near-infrared into the optical, where the EOR and IHL components of the extragalactic background can be cleanly distinguished and separated. We will study the history of IHL production by implementing a multi-band cross-correlation analysis, and use this information to carry out a deep search for an EOR component. In subsequent flights we plan joint observations with weak lensing maps, with an optimized set of filter bands to measure spectral cross-correlations, to fully elucidate the history of IHL light production.

Concerns, attitudes, beliefs and information seeking practices with respect to nutrition-related issues: a qualitative study in French pregnant women.

PubMed

Bianchi, Clélia M; Huneau, Jean-François; Le Goff, Gaëlle; Verger, Eric O; Mariotti, François; Gurviez, Patricia

2016-10-12

From a life course perspective, pregnancy leads to a rise in nutrition awareness and an increase in information flow in favour of adopting healthier eating behaviours. This qualitative study was designed to better understand the determinants of eating behaviours in French pregnant women by focusing on their concerns, attitudes and beliefs and their nutrition-related information seeking practices. Seven focus groups were conducted, involving a total of 40 French pregnant women. An inductive thematic approach, adapted from the grounded theory, was adopted to analyse the data. Two major themes were identified: eating behaviour and nutrition-related information behaviour. The eating behaviour theme was divided into four sub-themes using the attribution theory. Three external causes affected the eating behaviour of pregnant women (food restrictions, physiological changes and weight gain), and led to frustration and a perceived loss of control. By contrast the adoption of a healthier diet was perceived as internal by pregnant women, and resulted in self-fulfilment and empowerment regarding the health and the well-being of their baby and themselves, and their weight gain management. Greater attention was paid to nutrition-related information obtained from healthcare providers, the social environment and the mass media. Information was passively absorbed or actively sought by pregnant women, but most was perceived as contradictory, which led to confusion. Pregnancy is accompanied by a rise in nutrition awareness, substantiated by eating behaviour modifications due to external and internal causes. However, conflicts between and within information sources result in confusion that can limit the adoption of healthier eating behaviour.

Lived experience of epilepsy from the perspective of children in Taiwan.

PubMed

Chen, Hsiu-Jung; Chen, Yueh-Chih; Yang, Hui-Chuan; Chi, Ching-Shiang

2010-05-01

The purpose of this study was to explore the lived experiences of school-aged children with epilepsy in Taiwan. Epilepsy affects many people worldwide, especially school-aged children, but few studies have examined children's viewpoints of their experiences with epilepsy. An exploratory, phenomenological interview design was used. Children (ages 7-12 years) with well-controlled epilepsy and no developmental delay were recruited from a hospital in central Taiwan. Data were collected from 15 children using a semi-structured interview guide. Interviews were tape-recorded with permission from parents and children. Verbatim transcripts were analysed using Colazzi's phenomenological method. Two themes emerged from the analysis. The first theme, 'living with epilepsy', had two subthemes: disease-related experiences and school-related issues. The second theme, 'coping with epilepsy', had two subthemes: developing strategies to manage or reduce seizures and seeking support from family members. Taiwanese children with epilepsy had similar lived experiences as their counterparts in Western culture, e.g. unpleasant somatic symptoms, difficulty learning and troubled peer relationships. Taiwanese children also coped similarly with epilepsy by taking medications to control seizures, but they differed from their Western counterparts in trying to self-manage seizures and seeking support from family members. Public health and school nurses can apply our findings to educate school teachers and parents about epilepsy and encourage activities that allow children with and without epilepsy to interact, thus improving peer relationships and reducing stigmatisation. Children with and without epilepsy would also benefit from an age-appropriate education manual that includes causes of epilepsy, treatment, dealing with seizures and psychological and social adaptation.

Designing a Leadership Development Program for Surgeons

PubMed Central

Jaffe, Gregory A.; Pradarelli, Jason C.; Lemak, Christy Harris; Mulholland, Michael W.; Dimick, Justin B.

2015-01-01

Background Although numerous leadership development programs exist in healthcare, no programs have been specifically designed to meet the needs of surgeons. This study aimed to elicit practicing surgeons’ motivations and desired goals for leadership training in order to design an evidence-based Leadership Development Program (LDP) in surgery. Materials and Methods At a large academic health center, we conducted semi-structured interviews with 24 surgical faculty members who voluntarily applied and were selected for participation in a newly created LDP. Transcriptions of the interviews were analyzed using analyst triangulation and thematic coding in order to extract major themes regarding surgeons’ motivations and perceived needs for leadership knowledge and skills. Themes from interview responses were then used to design the program curriculum specifically to meet the leadership needs of surgical faculty. Results Three major themes emerged regarding surgeons’ motivations for seeking leadership training: 1) Recognizing key gaps in their formal preparation for leadership roles; 2) Exhibiting an appetite for personal self-improvement; and 3) Seeking leadership guidance for career advancement. Participants’ interviews revealed four specific domains of knowledge and skills that they indicated as desired takeaways from a leadership development program: 1) leadership and communication; 2) team building; 3) business acumen/finance; and 4) greater understanding of the healthcare context. Conclusions Interviews with surgical faculty members identified gaps in prior leadership training and demonstrated concrete motivations and specific goals for participating in a formal leadership program. A Leadership Development Program that is specifically tailored to address the needs of surgical faculty may benefit surgeons at a personal and institutional level. PMID:26323368

Living with the health and social inequities of a disability: a critical feminist study.

PubMed

Bethune-Davies, Patricia; McWilliam, Carol L; Berman, Helene

2006-03-01

Clients living at home with chronic disabling conditions together with their caregivers, service providers, and policymakers face major challenges in optimizing health care. In this critical feminist interpretive study we examined the experiences of women receiving home care for chronic disabling conditions. Five themes emerged: struggling with the embodied limitations of disabling chronic conditions; actively seeking health; struggling with service limitations; seeking ways to manage; and living with isolation and marginalization. Having done this study, we learned that home care services do not always contribute sufficiently to the overall health and well-being of women living with chronic disabling conditions and, in fact, may negatively impact upon their health.

Comparing Help-Seeking Behavior of Male and Female Survivors of Sexual Assault: A Content Analysis of a Hotline.

PubMed

Young, Stephen M; Pruett, Jana A; Colvin, Marianna L

2018-06-01

This content analysis examines written documentation of telephone calls to a regional sexual assault hotline over a 5-year period. All male callers identified as primary victims were selected for analysis ( n = 58) and a corresponding sample of female primary victims ( n = 58) were randomly selected for comparison to better understand the help-seeking behavior of sexual assault survivors and inform services accordingly. A summative content analysis revealed significant contrasting themes between male and female victims, including females significantly receiving more referrals and males accessing the hotline to tell their experience of being sexually assaulted due to perceived limited support. Implications for training, practice, and future research are discussed.

A New Method to Measure the Post-reionization Ionizing Background from the Joint Distribution of Lyα and Lyβ Forest Transmission

NASA Astrophysics Data System (ADS)

Davies, Frederick B.; Hennawi, Joseph F.; Eilers, Anna-Christina; Lukić, Zarija

2018-03-01

The amplitude of the ionizing background that pervades the intergalactic medium (IGM) at the end of the epoch of reionization provides a valuable constraint on the emissivity of the sources that reionized the universe. While measurements of the ionizing background at lower redshifts rely on a simulation-calibrated mapping between the photoionization rate and the mean transmission of the Lyα forest, at z ≳ 6 the IGM becomes increasingly opaque and transmission arises solely in narrow spikes separated by saturated Gunn–Peterson troughs. In this regime, the traditional approach of measuring the average transmission over large ∼50 Mpc/h regions is less sensitive and suboptimal. In addition, the five times smaller oscillator strength of the Lyβ transition implies that the Lyβ forest is considerably more transparent at z ≳ 6, even in the presence of contamination by foreground z ∼ 5 Lyα forest absorption. In this work we present a novel statistical approach to analyze the joint distribution of transmission spikes in the cospatial z ∼ 6 Lyα and Lyβ forests. Our method relies on approximate Bayesian computation (ABC), which circumvents the necessity of computing the intractable likelihood function describing the highly correlated Lyα and Lyβ transmission. We apply ABC to mock data generated from a large-volume hydrodynamical simulation combined with a state-of-the-art model of ionizing background fluctuations in the post-reionization IGM and show that it is sensitive to higher IGM neutral hydrogen fractions than previous techniques. As a proof of concept, we apply this methodology to a real spectrum of a z = 6.54 quasar and measure the ionizing background from 5.4 ≤ z ≤ 6.4 along this sightline with ∼0.2 dex statistical uncertainties. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Experiences of experts about the instances of plagiarism

PubMed Central

Keyvanara, Mahmod; Ojaghi, Rezvan; Sohrabi, Mozafar Cheshmeh; Papi, Ahmad

2013-01-01

Introduction: Plagiarism is defined as intentional deceiving or lack of honesty, which deprives others from both material and spiritual possessions. Ethics is considered as one of the most important aspects of evaluating the quality of higher education. Moreover, scientific ethics should be reflected from university values, as a specialized institution, rather than being a reflection of the others cares. Therefore, the main aim of the present study is explore of expert experiences about plagiarism in Isfahan University of Medical Sciences. Materials and Methods: This study employed qualitative method with using in-deep interview. The research participants consisted of 21, who tend to this work. Semi structure interview were conducted and recorded. The method of analyzing data was ‘thematic analysis’. The data were transcribed and saved on computer after each interview. Themes and sub-themes were extracted. Finally, relevant sub-themes were arranged in a category and suggested were presented. Result: Analyzing data showed 600 primary codes, 40 sub-themes and 6 themes. The main themes included repeated works, non-normative adoption, non-normative adaptation, shares distribution, forging, and profit-seeking, each of which consisted of one or several subgroups. Conclusion: The findings of this study show that since, there are numerous ways of cheating, the universities’ research committees must create institutions in order to educate the individuals how to avoid plagiarism. In addition, providing information about different types of scientific violations, as well as their following punishments might lead to the decrease of such misbehaviors. PMID:24083282

What's eating the internet? Content and perceived harm of pro-eating disorder websites.

PubMed

Steakley-Freeman, Diana M; Jarvis-Creasey, Zachary L; Wesselmann, Eric D

2015-12-01

The internet is a popular tool for information dissemination and community building, serving many purposes from social networking to support seeking. However, there may be a downside to using some online support communities. For individuals with eating disorders (EDs), it is possible that certain online communities may reinforce the negative social aspects that encourage these disorders, rather than positive aspects that would facilitate treatment and recovery. Previous research identified several linguistic themes present on pro-eating disorder websites in an attempt to better understand the web-based conversation in the pro-eating disorder movement. We hypothesized that differences in theme presentation may predict changes in perceived harm. The present study sought to understand the perceived harm, and presentation patterns of pro-eating disorder (Pro-ED) website content. We replicated and extended previous research by having laypersons code these websites' content using previously identified linguistic themes and rate perceived harm. Our data replicate and extend the previous research by finding the same associations between co-occurring themes, and investigating associated perceived harm. We found that themes of Sacrifice, Control, Deceit, and Solidarity were associated with the highest perceived harm scores. In addition, we suggest an initial conceptualization of the "Eating Disorder Lifestyle", and its associations with the themes of Isolation, Success, and Solidarity. This research may provide clinicians with information to better understand the potential influence these sites have on eating disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sociostructural factors influencing health behaviors of urban African-American men.

PubMed

Plowden, Keith O; Young, Anthony E

2003-06-01

African-American men are suffering disproportionately from most illnesses. Seemingly, action is needed if health disparities that disproportionately affect African-American men as compared to their White and female counterparts are to be reduced or eliminated. An important step in decreasing common health disparities evidenced among African-American men is to understand social factors that act as motivators and barriers to seeking care for most of this vulnerable population. Following a constructionist epistemology, this study used ethnography to explore social structure factors that motivate urban African-American men to seek care. Leininger's Culture Care Diversity and Universality Theory guided this study. Qualitative interviews were conducted with urban African-American men and other individuals in the community to explore understanding, attitudes, and beliefs about health. Critical issues examined included social factors associated with health seeking behaviors. Themes that emerged from these data indicated that critical social factors include: 1) Kinship/significant others; 2) accessibility of resources; 3) ethnohealth belief; and 4) accepting caring environment. The data also indicated a relationship between these social factors and health seeking behaviors of urban African-American men.

Parental professional help-seeking for infant sleep.

PubMed

Hsu, Pei-Wen; Wu, Wei-Wen; Tung, Yi-Ching; Thomas, Karen A; Tsai, Shao-Yu

2017-12-01

To explore the perceptions and experiences of parental professional help-seeking for infant sleep and sleep-related concerns. Infant sleep is a frequent concern for parents. However, very little is known about the reasons parents seek, do not seek or delay seeking professional attention about their concerns related to infant sleep. A qualitative study design was used. Twenty audio-taped interviews with parents of healthy 12-month-old infants were conducted at a university-affiliated hospital or parents' homes depending on where parents felt more comfortable discussing their personal views and medical help-seeking experiences. Thematic content analysis was performed to determine specific patterns and similarities within and between interview data. Three main themes developed from the interviews were as follows: (i) uncertainty about infant sleep; (ii) I can handle infant sleep; and (iii) I am not satisfied with the professional services provided for infant sleep. Overall, parents knew little about or misunderstood infant sleep behaviours. Lack of proper information and knowledge about infant sleep influenced parents' motivation for professional help-seeking and help-receiving. Parents who have consulted a healthcare professional but received unsatisfactory responses, such as an ambivalent attitude or insufficient assessment, reported being less motivated or unwilling to seek medical help again. Our study demonstrates the complexity of parental professional help-seeking and receiving for infant sleep. Findings suggest that parents perceive a wide range of barriers that influence the likelihood that they will seek professional advice for infant sleep. Reducing knowledge barriers and providing adequate attention at all well-infant visits would facilitate parental use of healthcare services to manage problematic infant sleep behaviours. © 2017 John Wiley & Sons Ltd.

Redefining self: patients' decision making about treatment for multiple sclerosis.

PubMed

Lowden, Diane; Lee, Virginia; Ritchie, Judith A

2014-08-01

The treatment of multiple sclerosis (MS) has become possible with the advent of disease-modifying therapies, but little is known about patients' experiences when faced with a complex array of treatment options. The purpose of this phenomenological study was to explore the lived experience of making a first decision about treatment with disease-modifying therapies for relapsing-remitting MS. Nine participants shared their perspectives on negotiating the decision to accept, refuse, or delay treatment. All individuals described a core theme in which decision making about treatment was part of a process of coming to a "redefined self." This core theme included reflections about self-image, quality of life, goals, and being a person with MS. Six common themes supporting this core theme were (a) weighing and deciding what's important, (b) acknowledging the illness as part of oneself, (c) playing the mental game, (d) seeking credible resources, (e) evaluating symptoms and fit with quality of life, and (f) managing the roles and involvement of family. The findings of this study provide a greater understanding about the experience of making a therapeutic choice for those with MS and offer insights for nurses when supporting patients faced with options about treatment.

User Experience and Care Integration in Transitional Care for Older People From Hospital to Home: A Meta-Synthesis.

PubMed

Allen, Jacqueline; Hutchinson, Alison M; Brown, Rhonda; Livingston, Patricia M

2017-01-01

This meta-synthesis aimed to improve understanding of user experience of older people, carers, and health providers; and care integration in the care of older people transitioning from hospital to home. Following our systematic search, we identified and synthesized 20 studies, and constructed a comprehensive framework. We derived four themes: (1) 'Who is taking care of what? Trying to work together"; (2) 'Falling short of the mark'; (3) 'A proper discharge'; and (4) 'You adjust somehow.' The themes that emerged from the studies reflected users' experience of discharge and transitional care as a social process of 'negotiation and navigation of independence (older people/carers), or dependence (health providers).' Users engaged in negotiation and navigation through the interrogative strategies of questioning, discussion, information provision, information seeking, assessment, and translation. The derived themes reflected care integration that facilitated, or a lack of care integration that constrained, users' experiences of negotiation and navigation of independence/dependence. © The Author(s) 2016.

Object relations perspectives on "Phantom of the Opera" and its demon lover theme: the modern film.

PubMed

Kavaler-Adler, Susan

2009-06-01

This study of the modern film version of "Phantom of the Opera" employs a mythic theme to illustrate how women can involve themselves with charismatic and eroticized narcissistic men, who are unavailable for true relationship within the conscious world of societal connection. How can the healthy-heroic woman extricate herself from the seductive web of such men, men who seek to own the women--not through sexual relations--but through ownership and control of the women's creative talents? What are the developmental, internal world, dynamics that spell out the muse turned demon/lover theme in British and American Object Relations terms? Similar to the mythic vampire who entrances women to suck their blood, the male muse haunts the female artist to possess her talents. The "demon lover" creates himself to woo the unsuspecting female with potential but yet unrealized creative talents. He woos through entrancement, like so many psychologically wounded narcissistic characters who require mirroring to have any sense of existence!

Exploring awareness and help-seeking intentions for testicular symptoms among heterosexual, gay, and bisexual men in Ireland: A qualitative descriptive study.

PubMed

Saab, Mohamad M; Landers, Margaret; Hegarty, Josephine

2017-02-01

The incidence of malignant and benign testicular disorders among young men is on the rise. Evidence from three reviews suggest that men's knowledge of these disorders is lacking and their help-seeking intention for testicular symptoms is suboptimal. Qualitative studies have addressed men's awareness of testicular cancer, with none exploring their awareness of non-malignant diseases such as epididymitis, testicular torsion, and varicocele and none including sexual minorities. To explore, in-depth, heterosexual, gay, and bisexual men's awareness of testicular disorders and their help-seeking intentions for testicular symptoms in the Irish context. This study used a qualitative descriptive approach. Data were collected via face-to-face individual interviews and focus groups. Participation was sought from a number of community and youth organisations and one university in Southern Ireland. Maximum variation and snowball sampling were used to recruit a heterogeneous sample. A total of 29 men partook in this study. Participants were men, aged between 18 and 50 years, and residents of the Republic of Ireland. All interviews were audio-recorded and transcribed verbatim. Reflective field notes were taken following each interview. A summary of the interview was shared with selected participants for member-check. Data were analysed and validated by three researchers. Inductive qualitative analysis of manifest content was used. Latent content was captured in the field notes. Data analysis yielded two key themes. The themes that emerged from the interviews were: Awareness of testicular disorders and their screening, and help-seeking intentions for testicular symptoms. Although most participants heard of testicular cancer, most did not know the different aspects of this malignancy including its risk factors, symptoms, treatments, and screening. Several men had a number of misconceptions around testicular disorders which negatively impacted their intentions to seek prompt help. Intentions to delay help-seeking for testicular symptoms were often linked to a number of emotional factors including fear and embarrassment, and social normative factors such as machoism and stoicism. In this study, culture was perceived by some participants as a barrier to awareness and help-seeking. In contrast, many believed that young men, especially those who self-identify as gay, are becoming increasingly interested in their own health. Findings suggest the need to educate young men about testicular disorders and symptoms. This could be achieved through conducting health promotion campaigns that appeal to younger men, drafting national men's health policies, and normalising open discussions about testicular health at a young age. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nurses' attitudes to assisted suicide: sociodemographic factors.

PubMed

Evans, Luke

This literature review seeks to explore the factors that influence nurses' attitudes towards assisted suicide. A poll conducted by the Royal College of Nursing (RCN) showed that 49% of nurses supported assisted suicide while 40% were opposed to it. A literature review resulted in 16 articles being identified for data synthesis using a recognised critiquing framework. The articles revealed four key themes: nursing specialty, level of education, geographical location and religion. It was concluded that these four themes are key to understanding a nurse's attitude towards assisted suicide. Nursing staff need to be aware of their own influences on this topic, since they will inevitably be involved in the process in some way or another, in countries where assisted suicide has been legalised.

[Mercosur's regional health agenda: architecture and themes].

PubMed

Queiroz, Luisa Guimaraes; Giovanella, Ligia

2011-08-01

This article describes the shaping of institutional health spaces in the Mercosur, with analysis of themes and results and considerations on the construction of the regional agenda and on the effects of regional economic integration processes on health policies and systems. We discuss the organization, operation, focus topics, and results achieved in specific health forums (Meeting of Ministers of Health and Sub-Working Group 11), seeking to analyze the architecture and issues addressed by the regional agenda and drawing parallels with the European experience. The aim of this reflection is to identify how the work done by Mercosur structures contributes to building a regional agenda, with the expectation that the integration can contribute to reducing inequalities in access to health care in the region.

Decision making processes in people with symptoms of acute myocardial infarction: qualitative study

PubMed Central

Pattenden, Jill; Watt, Ian; Lewin, Robert J P; Stanford, Neil

2002-01-01

Objective To identify the themes that influence decision making processes used by patients with symptoms of acute myocardial infarction. Design Qualitative study using semistructured interviews. Setting Two district hospitals in North Yorkshire. Participants 22 patients admitted to hospital with confirmed second, third, or fourth acute myocardial infarction. Main outcome measure Patients' perceptions of their experience between the onset of symptoms and the decision to seek medical help. Results Six main themes that influence the decision making process were identified: appraisal of symptoms, perceived risk, previous experience, psychological and emotional factors, use of the NHS, and context of the event. Conclusions Knowledge of symptoms may not be enough to promote prompt action in the event of an acute myocardial infarction. Cognitive and emotional processes, individual beliefs and values, and the influence of the context of the event should also be considered in individual interventions designed to reduce delay in the event of symptoms of acute myocardial infarction. What is already known on this topicIndividual sociodemographic and clinical characteristics affect the time to seeking medical care in patients with symptoms of acute myocardial infarctionAppraisal of symptoms is difficult; people with classic and severe symptoms are more likely to take prompt actionWhat this study addsThe decision to seek medical help in patients who have had one or more previous myocardial infarctions is a complex processSimply providing patients with information on symptoms of acute myocardial infarction, and what to do in the event of these symptoms, may not be sufficient to promote prompt action PMID:11976241

Strategies for Faith Engagement within One's Career: The Role of Uganda Christian University in Preparing Students for Postgraduation Life

ERIC Educational Resources Information Center

Rugyendo, Medard

2015-01-01

This article examines the role of Uganda Christian University (UCU) in devising strategies for the sustenance of Christian faith in one's career for the betterment of the society despite its social ills. The current theme of UCU is "A Complete Education for a Complete Person." As a Christian university, UCU seeks to provide a positive…

In Search of Excellence: The 2015 Notable Children's Books in the Language Arts

ERIC Educational Resources Information Center

Journal of Children's Literature, 2015

2015-01-01

As readers, we often seek out books that will help us find our way or will provide us with new insights. We select books for classrooms and children based on their interests, questions, and life situations. With this in mind, the selections this year are organized around the theme of searching. We search for peace around the world, among our own…

Distancing at Close Range: Making Strange Devices in Dorothy Heathcote's Process Drama "Teaching Political Awareness through Drama"

ERIC Educational Resources Information Center

Eriksson, Stig A.

2011-01-01

By refocusing traditions preoccupied with stimulating critical reflection, the article seeks to contribute to a rekindling of a socially oriented drama teaching and to add to the reservoir of teacher reflection in the field. A passage of a drama by Dorothy Heathcote is analysed, in which the theme of pollution is the concrete starting point,…

"A steep learning curve": junior doctor perspectives on the transition from medical student to the health-care workplace.

PubMed

Sturman, Nancy; Tan, Zachary; Turner, Jane

2017-05-26

The transition from medical student to hospital-based first year junior doctor (termed "intern" in Australia) is known to be challenging, and recent changes in clinical learning environments may reduce graduate preparedness for the intern workplace. Although manageable challenges and transitions are a stimulus to learning, levels of burnout in junior medical colleagues are concerning. In order to prepare and support medical graduates, educators need to understand contemporary junior doctor perspectives on this transition. Final-year University of Queensland medical students recruited junior doctors working in diverse hospital settings, and videorecorded individual semi-structured interviews about their transition from medical student to working as a junior doctor. Two clinical academics (NS and JT) and an intern (ZT) independently conducted a descriptive analysis of interview transcripts, and identified preliminary emerging concepts and themes, before reaching agreement by consensus on the major overarching themes. Three key themes emerged from the analysis of 15 interviews: internship as a "steep learning curve"; relationships and team; and seeking help. Participants described the intern transition as physically, mentally and emotionally exhausting. They learned to manage long days, administrative and clinical tasks, frequent interruptions and time pressures; identify priorities; deal with criticism without compromising key relationships; communicate succinctly; understand team roles (including their own status within hospital hierarchies); and negotiate conflict. Participants reported a drop in self-confidence, and difficulty maintaining self-care and social relationships. Although participants emphasised the importance of escalating concerns and seeking help to manage patients, they appeared more reluctant to seek help for personal issues and reported a number of barriers to doing so. Findings may assist educators in refining their intern preparation and intern training curricula, and ensuring that medical school and intern preparation priorities are not seen as competing. Insights from non-medical disciplines into the organisational and relational challenges facing junior doctors and their health-care teams may enhance inter-professional learning opportunities. Workplace support and teaching, especially from junior colleagues, is highly valued during the demanding intern transition.

Neutral hydrogen in the post-reionization universe

NASA Astrophysics Data System (ADS)

Padmanabhan, Hamsa

2018-05-01

The evolution of neutral hydrogen (HI) across redshifts is a powerful probe of cosmology, large scale structure in the universe and the intergalactic medium. Using a data-driven halo model to describe the distribution of HI in the post-reionization universe (z ~ 5 to 0), we obtain the best-fitting parameters from a rich sample of observational data: low redshift 21-cm emission line studies, intermediate redshift intensity mapping experiments, and higher redshift Damped Lyman Alpha (DLA) observations. Our model describes the abundance and clustering of neutral hydrogen across redshifts 0 - 5, and is useful for investigating different aspects of galaxy evolution and for comparison with hydrodynamical simulations. The framework can be applied for forecasting future observations with neutral hydrogen, and extended to the case of intensity mapping with molecular and other line transitions at intermediate redshifts.

A Magnified View of the Epoch of Reionization with the Hubble Frontier Fields

NASA Astrophysics Data System (ADS)

Livermore, Rachael C.; Finkelstein, Steven L.; Lotz, Jennifer M.

2017-06-01

The Hubble Frontier Fields program has obtained deep optical and near-infrared Hubble Space Telescope imaging of six galaxy clusters and associated parallel fields. The depth of the imaging (m_AB ~ 29) means we can identify faint galaxies at z >6, and those in the cluster fields also benefit from magnification due to strong gravitational lensing. Using wavelet decomposition to subtract the foreground cluster galaxies, we can reach intrinsic absolute magnitudes of M_UV ~ -12.5 at z ~ 6. Here, we present the UV luminosity functions at 6

The Use of the Time Average Visibility for Analyzing HERA-19 Commissioning Data

NASA Astrophysics Data System (ADS)

Gallardo, Samavarti; Benefo, Roshan; La Plante, Paul; Aguirre, James; HERA Collaboration

2018-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope that will be observing large structure throughout the cosmic reionzation epoch. This will allow us to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. We develop a simple and robust observable for the HERA-19 commissioning data, the Time Average Visibility (TAV). We compare both redundantly and absolutely calibrated visibilities to detailed instrument simulations and to analytical expectations, and explore the signal present in the TAV. The TAV has already been demonstrated as a method to reject poorly performing antennas, and may be improved with this work to allow a simple cross-check of the calibration solutions without imaging.

Detection of an oxygen emission line from a high-redshift galaxy in the reionization epoch.

PubMed

Inoue, Akio K; Tamura, Yoichi; Matsuo, Hiroshi; Mawatari, Ken; Shimizu, Ikkoh; Shibuya, Takatoshi; Ota, Kazuaki; Yoshida, Naoki; Zackrisson, Erik; Kashikawa, Nobunari; Kohno, Kotaro; Umehata, Hideki; Hatsukade, Bunyo; Iye, Masanori; Matsuda, Yuichi; Okamoto, Takashi; Yamaguchi, Yuki

2016-06-24

The physical properties and elemental abundances of the interstellar medium in galaxies during cosmic reionization are important for understanding the role of galaxies in this process. We report the Atacama Large Millimeter/submillimeter Array detection of an oxygen emission line at a wavelength of 88 micrometers from a galaxy at an epoch about 700 million years after the Big Bang. The oxygen abundance of this galaxy is estimated at about one-tenth that of the Sun. The nondetection of far-infrared continuum emission indicates a deficiency of interstellar dust in the galaxy. A carbon emission line at a wavelength of 158 micrometers is also not detected, implying an unusually small amount of neutral gas. These properties might allow ionizing photons to escape into the intergalactic medium. Copyright © 2016, American Association for the Advancement of Science.

Neural Network Emulation of Reionization Simulations

NASA Astrophysics Data System (ADS)

Schmit, Claude J.; Pritchard, Jonathan R.

2018-05-01

Next generation radio experiments such as LOFAR, HERA and SKA are expected to probe the Epoch of Reionization and claim a first direct detection of the cosmic 21cm signal within the next decade. One of the major challenges for these experiments will be dealing with enormous incoming data volumes. Machine learning is key to increasing our data analysis efficiency. We consider the use of an artificial neural network to emulate 21cmFAST simulations and use it in a Bayesian parameter inference study. We then compare the network predictions to a direct evaluation of the EoR simulations and analyse the dependence of the results on the training set size. We find that the use of a training set of size 100 samples can recover the error contours of a full scale MCMC analysis which evaluates the model at each step.

Dark-ages Reionization and Galaxy Formation Simulation - XIV. Gas accretion, cooling, and star formation in dwarf galaxies at high redshift

NASA Astrophysics Data System (ADS)

Qin, Yuxiang; Duffy, Alan R.; Mutch, Simon J.; Poole, Gregory B.; Geil, Paul M.; Mesinger, Andrei; Wyithe, J. Stuart B.

2018-06-01

We study dwarf galaxy formation at high redshift (z ≥ 5) using a suite of high-resolution, cosmological hydrodynamic simulations and a semi-analytic model (SAM). We focus on gas accretion, cooling, and star formation in this work by isolating the relevant process from reionization and supernova feedback, which will be further discussed in a companion paper. We apply the SAM to halo merger trees constructed from a collisionless N-body simulation sharing identical initial conditions to the hydrodynamic suite, and calibrate the free parameters against the stellar mass function predicted by the hydrodynamic simulations at z = 5. By making comparisons of the star formation history and gas components calculated by the two modelling techniques, we find that semi-analytic prescriptions that are commonly adopted in the literature of low-redshift galaxy formation do not accurately represent dwarf galaxy properties in the hydrodynamic simulation at earlier times. We propose three modifications to SAMs that will provide more accurate high-redshift simulations. These include (1) the halo mass and baryon fraction which are overestimated by collisionless N-body simulations; (2) the star formation efficiency which follows a different cosmic evolutionary path from the hydrodynamic simulation; and (3) the cooling rate which is not well defined for dwarf galaxies at high redshift. Accurate semi-analytic modelling of dwarf galaxy formation informed by detailed hydrodynamical modelling will facilitate reliable semi-analytic predictions over the large volumes needed for the study of reionization.

Effects of Antenna Beam Chromaticity on Redshifted 21 cm Power Spectrum and Implications for Hydrogen Epoch of Reionization Array

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan; Parsons, Aaron R.; DeBoer, David R.; Bowman, Judd D.; Ewall-Wice, Aaron M.; Neben, Abraham R.; Patra, Nipanjana

2016-07-01

Unaccounted for systematics from foregrounds and instruments can severely limit the sensitivity of current experiments from detecting redshifted 21 cm signals from the Epoch of Reionization (EoR). Upcoming experiments are faced with a challenge to deliver more collecting area per antenna element without degrading the data with systematics. This paper and its companions show that dishes are viable for achieving this balance using the Hydrogen Epoch of Reionization Array (HERA) as an example. Here, we specifically identify spectral systematics associated with the antenna power pattern as a significant detriment to all EoR experiments which causes the already bright foreground power to leak well beyond ideal limits and contaminate the otherwise clean EoR signal modes. A primary source of this chromaticity is reflections in the antenna-feed assembly and between structures in neighboring antennas. Using precise foreground simulations taking wide-field effects into account, we provide a generic framework to set cosmologically motivated design specifications on these reflections to prevent further EoR signal degradation. We show that HERA will not be impeded by such spectral systematics and demonstrate that even in a conservative scenario that does not perform removal of foregrounds, HERA will detect the EoR signal in line-of-sight k-modes, {k}\\parallel ≳ 0.2 h Mpc-1, with high significance. Under these conditions, all baselines in a 19-element HERA layout are capable of detecting EoR over a substantial observing window on the sky.

Simultaneously constraining the astrophysics of reionization and the epoch of heating with 21CMMC

NASA Astrophysics Data System (ADS)

Greig, Bradley; Mesinger, Andrei

2017-12-01

The cosmic 21 cm signal is set to revolutionize our understanding of the early Universe, allowing us to probe the 3D temperature and ionization structure of the intergalactic medium (IGM). It will open a window on to the unseen first galaxies, showing us how their UV and X-ray photons drove the cosmic milestones of the epoch of reionization (EoR) and epoch of heating (EoH). To facilitate parameter inference from the 21 cm signal, we previously developed 21CMMC: a Monte Carlo Markov Chain sampler of 3D EoR simulations. Here, we extend 21CMMC to include simultaneous modelling of the EoH, resulting in a complete Bayesian inference framework for the astrophysics dominating the observable epochs of the cosmic 21 cm signal. We demonstrate that second-generation interferometers, the Hydrogen Epoch of Reionization Array and Square Kilometre Array will be able to constrain ionizing and X-ray source properties of the first galaxies with a fractional precision of the order of ∼1-10 per cent (1σ). The ionization history of the Universe can be constrained to within a few percent. Using our extended framework, we quantify the bias in EoR parameter recovery incurred by the common simplification of a saturated spin temperature in the IGM. Depending on the extent of overlap between the EoR and the EoH, the recovered astrophysical parameters can be biased by ∼3σ-10σ.

Fossils of reionization in the local group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.; /Fermilab /KICP, Chicago /Chicago U., EFI; Kravtsov, Andrey V.

We use a combination of high-resolution gas dynamics simulations of high-redshift dwarf galaxies and dissipationless simulations of a Milky Way sized halo to estimate the expected abundance and spatial distribution of the dwarf satellite galaxies that formed most of their stars around z {approx} 8 and evolved only little since then. Such galaxies can be considered as fossils of the reionization era, and studying their properties could provide a direct window into the early, pre-reionization stages of galaxy formation. We show that 5-15% of the objects existing at z {approx} 8 do indeed survive until the present in the MWmore » like environment without significant evolution. This implies that it is plausible that the fossil dwarf galaxies do exist in the Local Group. Because such galaxies form their stellar systems early during the period of active merging and accretion, they should have spheroidal morphology regardless of their current distance from the host galaxy. We show that both the expected luminosity function and spatial distribution of dark matter halos which are likely to host fossil galaxies agree reasonably well with the observed distributions of the luminous (L{sub V} > 10{sup 6} Lsun) Local Group fossil candidates near the host galaxy (d<200 kpc). However, the predicted abundance is substantially larger (by a factor of 2-3) for fainter galaxies (L{sub V} < 10{sup 6} Lsun) at larger distances (d>300 kpc). We discuss several possible explanations for this discrepancy.« less

A Census of the LyC Photons that Form the UV Background During Reionization

NASA Astrophysics Data System (ADS)

Katz, Harley; Kimm, Taysun; Haehnelt, Martin; Sijacki, Debora; Rosdahl, Joakim; Blaizot, Jeremy

2018-05-01

We present a new, on-the-fly photon flux and absorption tracer algorithm designed to directly measure the contribution of different source populations to the metagalactic UV background and to the ionisation fraction of gas in the Universe. We use a suite of multifrequency radiation hydrodynamics simulations that are carefully calibrated to reproduce a realistic reionization history and galaxy properties at z ≥ 6, to disentangle the contribution of photons emitted by different mass haloes and by stars with different metallicities and ages to the UV background during reionization. While at very early cosmic times low mass, metal poor haloes provide most of the LyC photons, their contribution decreases steadily with time. At z = 6 it is the photons emitted by massive systems (Mhalo/M⊙ > 1010 h-1) and by the metal enriched stars (10-3 < Z/Z⊙ < 10-1.5) that provide the largest contribution to the ionising UV background. We demonstrate that there are large variations in the escape fraction depending on the source, with the escape fraction being highest (˜45 - 60%) for photons emitted by the oldest stars that penetrate into the IGM via low opacity channels carved by the ionising photons and supernova from younger stars. Before HII regions begin to overlap, the photoionisation rate strongly fluctuates between different, isolated HII bubbles, depending on the embedded ionising source, which we suggest may result in spatial variations in the properties of dwarf galaxies.

Lyman-α emitters gone missing: the different evolution of the bright and faint populations

NASA Astrophysics Data System (ADS)

Weinberger, Lewis H.; Kulkarni, Girish; Haehnelt, Martin G.; Choudhury, Tirthankar Roy

2018-06-01

We model the transmission of the Lyman-α line through the circum- and intergalactic media around dark matter haloes expected to host Lyman-alpha emitters (LAEs) at z ≥ 5.7, using the high-dynamic-range Sherwood simulations. We find very different CGM environments around more massive haloes (˜1011M⊙) compared to less massive haloes (˜109M⊙) at these redshifts, which can contribute to a different evolution of the Lyα transmission from LAEs within these haloes. Additionally we confirm that part of the differential evolution could result from bright LAEs being more likely to reside in larger ionized regions. We conclude that a combination of the CGM environment and the IGM ionization structure is likely to be responsible for the differential evolution of the bright and faint ends of the LAE luminosity function at z ≥ 6. More generally, we confirm the suggestion that the self-shielded neutral gas in the outskirts of the host halo can strongly attenuate the Lyα emission from high redshift galaxies. We find that this has a stronger effect on the more massive haloes hosting brighter LAEs. The faint-end of the LAE luminosity function is thus a more reliable probe of the average ionization state of the IGM. Comparing our model for LAEs with a range of observational data we find that the favoured reionization histories are our previously advocated `Late' and `Very Late' reionization histories, in which reionization finishes rather rapidly at around z ≃ 6.

Spectroscopic confirmation of an ultra-faint galaxy at the epoch of reionization

NASA Astrophysics Data System (ADS)

Hoag, Austin; Bradač, Maruša; Trenti, Michele; Treu, Tommaso; Schmidt, Kasper B.; Huang, Kuang-Han; Lemaux, Brian C.; He, Julie; Bernard, Stephanie R.; Abramson, Louis E.; Mason, Charlotte A.; Morishita, Takahiro; Pentericci, Laura; Schrabback, Tim

2017-04-01

Within one billion years of the Big Bang, intergalactic hydrogen was ionized by sources emitting ultraviolet and higher energy photons. This was the final phenomenon to globally affect all the baryons (visible matter) in the Universe. It is referred to as cosmic reionization and is an integral component of cosmology. It is broadly expected that intrinsically faint galaxies were the primary ionizing sources due to their abundance in this epoch1,2. However, at the highest redshifts (z > 7.5 lookback time 13.1 Gyr), all galaxies with spectroscopic confirmations to date are intrinsically bright and, therefore, not necessarily representative of the general population3. Here, we report the unequivocal spectroscopic detection of a low luminosity galaxy at z > 7.5. We detected the Lyman-α emission line at ˜10,504 Å in two separate observations with MOSFIRE4 on the Keck I Telescope and independently with the Hubble Space Telescope's slitless grism spectrograph, implying a source redshift of z = 7.640 ± 0.001. The galaxy is gravitationally magnified by the massive galaxy cluster MACS J1423.8+2404 (z = 0.545), with an estimated intrinsic luminosity of MAB = -19.6 ± 0.2 mag and a stellar mass of M⊙=3.0-0.8+1.5×108 solar masses. Both are an order of magnitude lower than the four other Lyman-α emitters currently known at z > 7.5, making it probably the most distant representative source of reionization found to date.

Using artificial neural networks to constrain the halo baryon fraction during reionization

NASA Astrophysics Data System (ADS)

Sullivan, David; Iliev, Ilian T.; Dixon, Keri L.

2018-01-01

Radiative feedback from stars and galaxies has been proposed as a potential solution to many of the tensions with simplistic galaxy formation models based on Λcold dark matter, such as the faint end of the ultraviolet (UV) luminosity function. The total energy budget of radiation could exceed that of galactic winds and supernovae combined, which has driven the development of sophisticated algorithms that evolve both the radiation field and the hydrodynamical response of gas simultaneously, in a cosmological context. We probe self-feedback on galactic scales using the adaptive mesh refinement, radiative transfer, hydrodynamics, and N-body code RAMSES-RT. Unlike previous studies which assume a homogeneous UV background, we self-consistently evolve both the radiation field and gas to constrain the halo baryon fraction during cosmic reionization. We demonstrate that the characteristic halo mass with mean baryon fraction half the cosmic mean, Mc(z), shows very little variation as a function of mass-weighted ionization fraction. Furthermore, we find that the inclusion of metal cooling and the ability to resolve scales small enough for self-shielding to become efficient leads to a significant drop in Mc when compared to recent studies. Finally, we develop an artificial neural network that is capable of predicting the baryon fraction of haloes based on recent tidal interactions, gas temperature, and mass-weighted ionization fraction. Such a model can be applied to any reionization history, and trivially incorporated into semi-analytical models of galaxy formation.

Probing the end of reionization with the near zones of z ≳ 6 QSOs

NASA Astrophysics Data System (ADS)

Keating, Laura C.; Haehnelt, Martin G.; Cantalupo, Sebastiano; Puchwein, Ewald

2015-11-01

QSO near zones are an important probe of the ionization state of the intergalactic medium (IGM) at z ˜ 6-7, at the end of reionization. We present here high-resolution cosmological 3D radiative transfer simulations of QSO environments for a wide range of host halo masses, 1010-12.5 M⊙. Our simulated near zones reproduce both the overall decrease of observed near-zone sizes at 6 < z < 7 and their scatter. The observable near-zone properties in our simulations depend only very weakly on the mass of the host halo. The size of the H II region expanding into the IGM is generally limited by (super-)Lyman Limit systems loosely associated with (low-mass) dark matter haloes. This leads to a strong dependence of near-zone size on direction and drives the large observed scatter. In the simulation centred on our most massive host halo, many sightlines show strong red damping wings even for initial volume averaged neutral hydrogen fractions as low as ˜10-3. For QSO lifetimes long enough to allow growth of the central supermassive black hole while optically bright, we can reproduce the observed near zone of ULAS J1120+0641 only with an IGM that is initially neutral. Our results suggest that larger samples of z > 7 QSOs will provide important constraints on the evolution of the neutral hydrogen fraction and thus on how late reionization ends.

AGN-driven helium reionization and the incidence of extended He III regions at redshift z > 3

NASA Astrophysics Data System (ADS)

Compostella, Michele; Cantalupo, Sebastiano; Porciani, Cristiano

2014-12-01

We use hydrodynamic simulations post-processed with the radiative-transfer code RADAMESH to assess recent claims that the low He II opacity observed in z > 3 quasar spectra may be incompatible with models of He II reionization driven by the observed population of active galactic nuclei (AGNs). In particular, building upon our previous work, we consider an early population of sources and start the radiative-transfer calculation at redshifts z ≥ 5. Our model faithfully reproduces the emissivity of optically selected AGNs as inferred from measurements of their luminosity function. We find that He II reionization is very extended in redshift (Δz ≥ 2) and highly spatially inhomogeneous. In fact, mock spectra extracted from the simulations show a large variability in the evolution of the He II effective optical depth within chunks of size Δz = 0.04. Regions with low opacity (τ_ {He {II}}^eff < 3) can be found at high redshift, in agreement with the most recent observations of UV-transmitting quasars. At the highest redshift currently probed by observations (z ˜ 3.4), our updated model predicts a much lower He II effective optical depth than previous simulations in the literature relieving most of the tension with the current data, that, however, still persists at about the (Gaussian) 1σ to 2σ level. Given the very small number of observed lines of sight, our analysis indicates that current data cannot rule out a purely AGN-driven scenario with high statistical significance.

A magnified young galaxy from about 500 million years after the Big Bang.

PubMed

Zheng, Wei; Postman, Marc; Zitrin, Adi; Moustakas, John; Shu, Xinwen; Jouvel, Stephanie; Høst, Ole; Molino, Alberto; Bradley, Larry; Coe, Dan; Moustakas, Leonidas A; Carrasco, Mauricio; Ford, Holland; Benítez, Narciso; Lauer, Tod R; Seitz, Stella; Bouwens, Rychard; Koekemoer, Anton; Medezinski, Elinor; Bartelmann, Matthias; Broadhurst, Tom; Donahue, Megan; Grillo, Claudio; Infante, Leopoldo; Jha, Saurabh W; Kelson, Daniel D; Lahav, Ofer; Lemze, Doron; Melchior, Peter; Meneghetti, Massimo; Merten, Julian; Nonino, Mario; Ogaz, Sara; Rosati, Piero; Umetsu, Keiichi; van der Wel, Arjen

2012-09-20

Re-ionization of the intergalactic medium occurred in the early Universe at redshift z ≈ 6-11, following the formation of the first generation of stars. Those young galaxies (where the bulk of stars formed) at a cosmic age of less than about 500 million years (z ≲ 10) remain largely unexplored because they are at or beyond the sensitivity limits of existing large telescopes. Understanding the properties of these galaxies is critical to identifying the source of the radiation that re-ionized the intergalactic medium. Gravitational lensing by galaxy clusters allows the detection of high-redshift galaxies fainter than what otherwise could be found in the deepest images of the sky. Here we report multiband observations of the cluster MACS J1149+2223 that have revealed (with high probability) a gravitationally magnified galaxy from the early Universe, at a redshift of z = 9.6 ± 0.2 (that is, a cosmic age of 490 ± 15 million years, or 3.6 per cent of the age of the Universe). We estimate that it formed less than 200 million years after the Big Bang (at the 95 per cent confidence level), implying a formation redshift of ≲14. Given the small sky area that our observations cover, faint galaxies seem to be abundant at such a young cosmic age, suggesting that they may be the dominant source for the early re-ionization of the intergalactic medium.

DISCOVERY OF A FAINT QUASAR AT z ∼ 6 AND IMPLICATIONS FOR COSMIC REIONIZATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Yongjung; Im, Myungshin; Jeon, Yiseul

2015-11-10

Recent studies suggest that faint active galactic nuclei may be responsible for the reionization of the universe. Confirmation of this scenario requires spectroscopic identification of faint quasars (M{sub 1450} > −24 mag) at z ≳ 6, but only a very small number of such quasars have been spectroscopically identified so far. Here, we report the discovery of a faint quasar IMS J220417.92+011144.8 at z ∼ 6 in a 12.5 deg{sup 2} region of the SA22 field of the Infrared Medium-deep Survey (IMS). The spectrum of the quasar shows a sharp break at ∼8443 Å, with emission lines redshifted to zmore » = 5.944 ± 0.002 and rest-frame ultraviolet continuum magnitude M{sub 1450} = −23.59 ± 0.10 AB mag. The discovery of IMS J220417.92+011144.8 is consistent with the expected number of quasars at z ∼ 6 estimated from quasar luminosity functions based on previous observations of spectroscopically identified low-luminosity quasars. This suggests that the number of M{sub 1450} ∼ −23 mag quasars at z ∼ 6 may not be high enough to fully account for the reionization of the universe. In addition, our study demonstrates that faint quasars in the early universe can be identified effectively with a moderately wide and deep near-infrared survey such as the IMS.« less

Information sought, information shared: exploring performance and image enhancing drug user-facilitated harm reduction information in online forums.

PubMed

Tighe, Boden; Dunn, Matthew; McKay, Fiona H; Piatkowski, Timothy

2017-07-21

There is good evidence to suggest that performance and image enhancing drug (PIED) use is increasing in Australia and that there is an increase in those using PIEDs who have never used another illicit substance. Peers have always been an important source of information in this group, though the rise of the Internet, and the increased use of Internet forums amongst substance consumers to share harm reduction information, means that PIED users may have access to a large array of views and opinions. The aim of this study was to explore the type of information that PIED users seek and share on these forums. An online search was conducted to identify online forums that discussed PIED use. Three discussion forums were included in this study: aussiegymjunkies.com, bodybuildingforums.com.au, and brotherhoodofpain.com. The primary source of data for this study was the 'threads' from the online forums. Threads were thematically analysed for overall content, leading to the identification of themes. One hundred thirty-four threads and 1716 individual posts from 450 unique avatars were included in this analysis. Two themes were identified: (1) personal experiences and advice and (2) referral to services and referral to the scientific literature. Internet forums are an accessible way for members of the PIED community to seek and share information to reduce the harms associated with PIED use. Forum members show concern for both their own and others' use and, where they lack information, will recommend seeking information from medical professionals. Anecdotal evidence is given high credence though the findings from the scientific literature are used to support opinions. The engagement of health professionals within forums could prove a useful strategy for engaging with this population to provide harm reduction interventions, particularly as forum members are clearly seeking further reliable information, and peers may act as a conduit between users and the health and medical profession.

Spotlight on equality of employment opportunities: A qualitative study of job seeking experiences of graduating nurses and physiotherapists from black and minority ethnic backgrounds.

PubMed

Hammond, John; Marshall-Lucette, Sylvie; Davies, Nigel; Ross, Fiona; Harris, Ruth

2017-09-01

There is growing attention in the UK and internationally to the representation of black and minority ethnic groups in healthcare education and the workplace. Although the NHS workforce is very diverse, ethnic minorities are unevenly spread across occupations, and considerably underrepresented in senior positions. Previous research has highlighted that this inequality also exists at junior levels with newly qualified nurses from non-White/British ethnic groups being less likely to get a job at graduation than their White/British colleagues. Although there is better national data on the scale of inequalities in the healthcare workforce, there is a gap in our understanding about the experience of job seeking, and the factors that influence disadvantage in nursing and other professions such as physiotherapy. This qualitative study seeks to fill that gap and explores the experience of student nurses (n=12) and physiotherapists (n=6) throughout their education and during the first 6-months post qualification to identify key experiences and milestones relating to successful employment particularly focusing on the perspectives from different ethnic groups. Participants were purposively sampled from one university to ensure diversity in ethnic group, age and gender. Using a phenomenological approach, in-depth semi-structured interviews were conducted at course completion and 6 months later. Two main themes were identified. The 'proactive self' ('It's up to me') theme included perceptions of employment success being due to student proactivity and resilience; qualities valued by employers. The second theme described the need to 'fit in' with organisational culture. Graduates described accommodating strategies where they modified aspects of their identity (clothing, cultural markers) to fit in. At one extreme, rather than fitting in, participants from minority ethnic backgrounds avoided applying to certain hospitals due to perceptions of discriminatory cultures, 'I wouldn't apply there 'cos you know, it's not really an ethnic hospital'. In contrast, some participants recognised that other graduates (usually white) did not need to change and aspects of their identity brought unsolicited rewards 'if your face fits then the barriers are reduced'. The findings indicate that success in getting work is perceived as determined by individual factors, and fitting in is enabled by strategies adopted by the individual rather than the workplace. Demands for change are more acute for graduates from black and minority ethnic backgrounds. This is an issue for healthcare organisations seeking to be inclusive and challenges employers and educators to acknowledge inequalities and take action to address them. Copyright © 2017 Elsevier Ltd. All rights reserved.

Women Empowerment through Health Information Seeking: A Qualitative Study

PubMed Central

Nikbakht Nasrabadi, Alireza; Sabzevari, Sakineh; Negahban Bonabi, Tayebeh

2015-01-01

Background Today, women empowering is an important issue.  Several methods have been introduced to empower women. Health information seeking is one of the most important activities in this regard. A wide range of capabilities have been reported as outcomes of health information seeking in several studies. As health information seeking is developed within personal-social interactions and also the health system context, it seems that the qualitative paradigm is appropriate to use in studies in this regard. This study aimed to explore how women’s empowerment through health information seeking is done. Methods In this qualitative content analysis study, data collection was done with regard to inclusion criteria, through purposive sampling by semi-structured interviews with 17 women and using documentation and field notes until data saturation. Qualitative data analysis was done constantly and simultaneous with data collection. Results Four central themes were emerged to explain women’s empowerment through health information seeking that included: a) Health concerns management with three subcategories of Better coping, Stress management, Control of situation, b) Collaborative care with two subcategories of Effective interaction with health professions and Participation in health decision making c) Individual development d) Self-protection with four sub- categories of Life style modification,  Preventive behaviors promoting, Self-care promoting, and  medication adherence. Conclusion The results of this study indicate the importance of women empowerment through foraging their health information seeking rights and comprehensive health information management. PMID:26005690

"Why doesn't she seek help for partner abuse?" An exploratory study with South Asian immigrant women.

PubMed

Ahmad, Farah; Driver, Natasha; McNally, Mary Jane; Stewart, Donna E

2009-08-01

This study explores why South Asian immigrant women with experiences of partner abuse delay seeking help from professionals. Three focus groups were conducted in Hindi language with South Asian immigrant women in Toronto. Twenty-two women participated with a mean age of 46 years (range 29-68 years). Thematic analysis was conducted on the transcribed data using constant comparison techniques within and across the groups. We found that three major themes emerged from the discussions: reasons for delayed help-seeking, turning points and talking to professionals. Women expressed delaying help-seeking to the point when "Pani sar se guzar jata he" (water crosses over your head). Their dominant reasons for delayed help-seeking were social stigma, rigid gender roles, marriage obligations, expected silence, loss of social support after migration and limited knowledge about available resources and myths about partner abuse. Women usually turned for help only after experiencing pronounced mental and physical health problems. The findings are interpreted in light of participants' immigration context and the socio-cultural norms of patriarchy, collectivism and familism. Prevention approaches to address partner abuse and delayed help-seeking among South Asian immigrant women should include tailored community education, social services to reduce vulnerability, and cultural competency of professionals. Further research and program evaluation is needed to advance the field.

Extinction and Reinstatement of Cocaine-seeking in Self-administering Mice is Associated with Bidirectional AMPAR-mediated Plasticity in the Nucleus Accumbens Shell.

PubMed

Ebner, Stephanie R; Larson, Erin B; Hearing, Matthew C; Ingebretson, Anna E; Thomas, Mark J

2018-06-07

Experience-dependent synaptic plasticity is an important component of both learning and motivational disturbances found in addicted individuals. Here, we investigated the role of cocaine experience-dependent plasticity at excitatory synapses in the nucleus accumbens shell (NAcSh) in relapse-related behavior in mice with a history of volitional cocaine self-administration. Using an extinction/reinstatement paradigm of cocaine-seeking behavior, we demonstrate that cocaine-experienced mice with extinguished cocaine-seeking behavior show potentiation of synaptic strength at excitatory inputs onto NAcSh medium spiny neurons (MSNs). Conversely, we found that exposure to various distinct types of reinstating stimuli (cocaine, cocaine-associated cues, yohimbine "stress") after extinction can produce a relative depotentiation of NAcSh synapses that is strongly associated with the magnitude of cocaine-seeking behavior exhibited in response to these challenges. Furthermore, we show that these effects are due to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-specific mechanisms that differ depending on the nature and context of the reinstatement-inducing stimuli. Together, our findings identify common themes as well as differential mechanisms that are likely important for the ability of diverse environmental stimuli to drive relapse to addictive-like cocaine-seeking behavior. Copyright © 2018. Published by Elsevier Ltd.

Healthcare-seeking behaviour in relation to sexual and reproductive health among Thai-born women in Sweden: a qualitative study.

PubMed

Åkerman, Eva; Essén, Birgitta; Westerling, Ragnar; Larsson, Elin

2017-02-01

Thailand is one of the most common countries of origin among immigrants in Sweden and Thai immigrants comprise the immigrant group most frequently diagnosed with HIV. Little is known about their healthcare-seeking behaviour and views on HIV prevention. This study explored Thai women's healthcare-seeking behaviour in relation to sexual and reproductive health and their views on HIV prevention. Nineteen in-depth interviews were conducted with Thai-born women in the Stockholm area. Three themes were identified: (1) poor access to healthcare in Sweden, preferring to seek care in Thailand; (2) partners playing a key role in women's access to healthcare; (3) no perceived risk of HIV, but a positive attitude towards prevention. Despite expressing sexual and reproductive healthcare needs, most women had not sought this type of care, except for the cervical cancer screening programme to which they had been invited. Identified barriers for poor access to healthcare were lack of knowledge about the healthcare system and language difficulties. To achieve 'healthcare on equal terms', programmes and interventions must meet Thai women's healthcare needs and consider what factors influence their care-seeking behaviour. Integrating HIV prevention and contraceptive counselling into the cervical screening programme might be one way to improve access.

A qualitative study of determinants of PTSD treatment initiation in veterans.

PubMed

Sayer, Nina A; Friedemann-Sanchez, Greta; Spoont, Michele; Murdoch, Maureen; Parker, Louise E; Chiros, Christine; Rosenheck, Robert

2009-01-01

Although there are effective treatments for Posttraumatic Stress Disorder (PTSD), many PTSD sufferers wait years to decades before seeking professional help, if they seek it at all. An understanding of factors affecting treatment initiation for PTSD can inform strategies to promote help-seeking. We conducted a qualitative study to identify determinants of PTSD treatment initiation among 44 U.S. military veterans from the Vietnam and Afghanistan/Iraq wars; half were and half were not receiving treatment. Participants described barriers to and facilitators of treatment initiation within themselves, the post-trauma socio-cultural environment, the health care and disability systems, and their social networks. Lack of knowledge about PTSD was a barrier that occurred at both the societal and individual levels. Another important barrier theme was the enduring effect of experiencing an invalidating socio-cultural environment following trauma exposure. In some cases, system and social network facilitation led to treatment initiation despite individual-level barriers, such as beliefs and values that conflicted with help-seeking. Our findings expand the dominant model of service utilization by explicit incorporation of factors outside the individual into a conceptual framework of PTSD treatment initiation. Finally, we offer suggestions regarding the direction of future research and the development of interventions to promote timely help-seeking for PTSD.

Online women-seeking-women personal ads and the deployment of "tomboy" identities.

PubMed

Farr, Daniel

2011-01-01

This article examines online women-seeking-women (WSW) personal ads that engage with tomboy identities and ideologies. This research demonstrates the importance of body and physicality among lesbian personal ads and the diversity of women using online personal ads. The meaning of "tomboy" in the language of WSW personal ads suggests major themes of use including: as an intermediate identity distinct within a butch/femme dichotomy, as a tempering agent for traditional femininity, as a fluid construct of personality, physicality, and body, as an understood descriptor of a particular aesthetic or physicality, and as synonymous with butch. To be a tomboy is to be simultaneously understood as a social stereotype, but also as complex, fluid, and of multiple meanings.

Influences to ADHD Problem Recognition: Mixed-Method Investigation and Recommendations to Reduce Disparities for Latino Youth.

PubMed

Haack, Lauren M; Meza, Jocelyn; Jiang, Yuanyuan; Araujo, Eva Jimenez; Pfiffner, Linda

2018-05-16

ADHD problem recognition serves as the first step of help seeking for ethnic minority families, such as Latinos, who underutilize ADHD services. The current mixed-method study explores underlying factors influencing recognition of ADHD problems in a sample of 159 school-aged youth. Parent-teacher informant discrepancy results suggest that parent ethnicity, problem domain, and child age influence ADHD problem recognition. Emerging themes from semi-structured qualitative interviews/focus groups conducted with eighteen Spanish-speaking Latino parents receiving school-based services for attention and behavior concerns support a range of recognized ADHD problems, beliefs about causes, and reactions to ADHD identification. Findings provide recommendations for reducing disparities in ADHD problem recognition and subsequent help seeking.

The experience of stigma among Black mental health consumers.

PubMed

Alvidrez, Jennifer; Snowden, Lonnie R; Kaiser, Dawn M

2008-08-01

Little is known about how stigma affects Black people receiving mental health treatment. For a project to develop a consumer-based stigma intervention, qualitative interviews were conducted with public-sector Black mental health consumers (N=34). Primary themes from the interviews regarding stigma concerns, experiences, and coping strategies were examined. Concerns about stigma prompted most consumers initially to avoid or delay treatment; once in treatment, consumers commonly faced stigmatizing reactions from others. Consumers identified numerous strategies to deal with stigma, including seeking support from accepting members of their existing social networks, and viewing their own health as more important than the reaction of others. These consumer perspectives may be valuable to Black individuals who are contemplating seeking mental health treatment.

Parents who use drugs: accounting for damage and its limitation.

PubMed

Rhodes, Tim; Bernays, Sarah; Houmoller, Kathrin

2010-10-01

Parents who use drugs parent in a context of heightened concern regarding the damaging effects of parental drug use on child welfare and family life. Yet there is little research exploring how parents who use drugs account for such damage and its limitation. We draw here upon analyses of audio-recorded depth qualitative interviews, conducted in south-east England between 2008 and 2009, with 29 parents who use drugs. Our approach to thematic analysis treated accounts as co-produced and socially situated. An over-arching theme of accounts was 'damage limitation'. Most damage limitation work centred on efforts to create a sense of normalcy of family life, involving keeping drug use secret from children, and investing heavily in strategies to maintain ambiguity regarding children's awareness. Our analysis highlights that damage limitation strategies double-up in accounts as resources of child protection as well as self protection. This illuminates tensions in the multiple functions that accounts of damage limitation can serve. We draw a distinction between accounts in which damage is qualified and those in which damage is accepted. Accounts of damage qualification highlight a theme of 'good enough' parenting. Accounts of damage acceptance highlight a theme of 'recovery'. We find that the interview accounts operate in response to a regulative norm of 'good parenting' in which one strives to deflect damaged identity through narratives of damage qualification and to seek understanding and acceptance through narratives of recovery. Noting the absence of space for parents who use drugs to openly reflect or talk about the challenges they face, we identify the need for social change interventions to create enabling environments for earlier help seeking and talking. Copyright © 2010 Elsevier Ltd. All rights reserved.

Responsible gambling among older adults: a qualitative exploration.

PubMed

Subramaniam, Mythily; Satghare, Pratika; Vaingankar, Janhavi A; Picco, Louisa; Browning, Colette J; Chong, Siow Ann; Thomas, Shane A

2017-04-04

Responsible gambling (RG) is defined as gambling for pleasure and entertainment but with an awareness of the likelihood of losing, an understanding of the associated risks and the ability to exercise control over one's gambling activity. The current study describes a qualitative approach to explore RG among older adults (aged 60 years and above) in Singapore and reports on the cognitive and behavioural strategies employed by them to regulate their gambling. Inclusion criteria included Singapore residents aged 60 years and above, who could speak in English, Chinese, Malay or Tamil and were current or past regular gamblers. Participants were recruited using a combination of network and purposive sampling. Socio-demographic information on age, age of onset of gambling, gender, ethnicity, marital status, education and employment was collected. The South Oaks Gambling Screen (SOGS) was used to collect information on gambling activities and problems associated with gambling behaviour. Qualitative interviews were conducted with 25 older adults (60 years and above) who currently gambled. The data was analyzed using thematic network analysis. This global theme of RG comprised two organising themes: self -developed strategies to limit gambling related harm and family interventions to reduce gambling harm. The basic themes included delayed gratification, perception of futility of gambling, setting limits, maintaining balance, help-seeking and awareness of disordered gambling in self or in others. Family interventions included pleading and threatening, compelling help-seeking as well as family exclusion order. The study highlights the significant role that families play in Asian societies in imposing RG. Education of family members both in terms of the importance of RG, and communication of the ways in which older adults can incorporate RG behaviours including the use of exclusion in specific scenarios is important.

Celebrate Your Freedom--Assuring Equal Justice for All. Law Day 2002 Planning Guide.

ERIC Educational Resources Information Center

White, Charles, Ed.

The theme for Law Day 2002 was set long before the tragic events of September 11, 2001, and its aftermath. The vision of Law Day planners was to plan programs on how the courts and legal system seek to assure equal access to justice for all people. This guide gives planners the tools for programs and discussions on legal aid, the "pro bono…

Materials Development in Three Italian CALL Projects: Seeking an Optimal Mix between In-Class and Out-of-Class Learning

ERIC Educational Resources Information Center

Levy, Mike; Kennedy, Claire

2010-01-01

This paper considers the design and development of CALL materials with the aim of achieving an optimal mix between in-class and out-of-class learning in the context of teaching Italian at an Australian university. The authors discuss three projects in relation to the following themes: (a) conceptions of the in-class/out-of-class relationship, (b)…

20 Years of EUROCALL: Learning from the Past, Looking to the Future. Proceedings [of the] 2013 EUROCALL Conference (Évora, Portugal, September 11-14, 2013)

ERIC Educational Resources Information Center

Bradley, Linda, Ed.; Thouësny, Sylvie, Ed.

2013-01-01

EUROCALL 2013's theme was "20 Years of EUROCALL: Learning from the Past, Looking to the Future." The conference seeked to establish an overview of EUROCALL's twentieth anniversary. As a professional organization, EUROCALL has been aiming, along its 20 years of existence, to promote innovative research, development and practice in the…

The Gaze or the Groove? Emerging Themes from the "New Meanings and Pathways: Community Dance and Dance Education Symposium" in Beijing

ERIC Educational Resources Information Center

Rowe, Nicholas; Buck, Ralph; Martin, Rosemary

2015-01-01

Established in 1954 and drawing heavily on dance conservatory models from Russia, the Beijing Dance Academy (BDA) has become a predominant influence on dance education in East Asia. As it addresses the artistic, cultural and educational needs of China into the twenty-first century, the BDA is now negotiating a new terrain and seeking new…

A Thousand Writers Writing: Seeking Change through the Radical Practice of Writing as a Way of Being

ERIC Educational Resources Information Center

Yagelski, Robert P.

2009-01-01

In this frankly utopian essay, Robert Yagelski's theme is the transformative power of writing as an act in and of itself. He makes us reevaluate our motivation and point for teaching writing in schools and asks us to consider an agenda that will quite frankly scare teachers as he explains why we need an ontology of writing. (Contains 6 notes.)

Reclaiming the everyday world: how long-term ventilated patients in critical care seek to gain aspects of power and control over their environment.

PubMed

Johnson, Patricia

2004-08-01

Critical care nurses are increasingly seeking to base patient care on evidence derived from research studies. The purpose of this study was to explore the meanings former patients attributed to being on long-term mechanical ventilation in a critical care unit (CCU) in Australia. Using Heideggerian phenomenology, unstructured interviews were undertaken with nine participants. Data were analysed thematically using the method developed by van Manen. Thematic analysis revealed four major themes. This article presents the findings from the theme titled: Reclaiming the everyday world, which describes how the study participants gained comfort from the presence of nurses and their families, sought control over their treatments, and questioned and interpreted the environment, in order to reclaim self. The study highlighted the central role of nurses in patient care, and served as a basis for a number of recommendations, which include recognising the significant role of nurses and family in patient care, and being aware that patients may want more control over their environment and instigate ways to facilitate this. Further research is warranted to examine CCU patients' perceived level of control and power, and to investigate the extent and type of involvement CCU patients would like to have in their care.

The experiences of frequent users of crisis helplines: A qualitative interview study.

PubMed

Middleton, Aves; Gunn, Jane; Bassilios, Bridget; Pirkis, Jane

2016-11-01

To understand why some users call crisis helplines frequently. Nineteen semi-structured telephone interviews were conducted with callers to Lifeline Australia who reported calling 20 times or more in the past month and provided informed consent. Interviews were audio-recorded and transcribed verbatim. Inductive thematic analysis was used to generate common themes. Approval was granted by The University of Melbourne Human Research Ethics Committee. Three overarching themes emerged from the data and included reasons for calling, service response and calling behaviours. Respondents called seeking someone to talk to, help with their mental health issues and assistance with negative life events. When they called, they found short-term benefits in the unrestricted support offered by the helpline. Over time they called about similar issues and described reactive, support-seeking and dependent calling behaviours. Frequent users of crisis helplines call about ongoing issues. They have developed distinctive calling behaviours which appear to occur through an interaction between their reasons for calling and the response they receive from the helpline. The ongoing nature of the issues prompting frequent users to call suggests that a service model that includes a continuity of care component may be more efficient in meeting their needs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Uncovering the unknown: A grounded theory study exploring the impact of self-awareness on the culture of feedback in residency education.

PubMed

Ramani, Subha; Könings, Karen; Mann, Karen V; van der Vleuten, Cees

2017-10-01

Self-assessment and reflection are essential for meaningful feedback. We aimed to explore whether the well-known Johari window model of self-awareness could guide feedback conversations between faculty and residents and enhance the institutional feedback culture. We had previously explored perceptions of residents and faculty regarding sociocultural factors impacting feedback. We re-analyzed data targeting themes related to self-assessment, reflection, feedback seeking and acceptance, aiming to generate individual and institutional feedback strategies applicable to each quadrant of the window. We identified the following themes for each quadrant: (1) Behaviors known to self and others - Validating the known; (2) Behaviors unknown to self but known to others - Accepting the blind; (3) Behaviors known to self and unknown to others - Disclosure of hidden; and (4) Behaviors unknown to self and others - Uncovering the unknown. Normalizing self-disclosure of limitations, encouraging feedback seeking, training in nonjudgmental feedback and providing opportunities for longitudinal relationships could promote self-awareness, ultimately expanding the "open" quadrant of the Johari window. The Johari window, a model of self-awareness in interpersonal communications, could provide a robust framework for individuals to improve their feedback conversations and institutions to design feedback initiatives that enhance its quality and impact.

A Qualitative Study of Young Adult Experiences in the Bariatric Healthcare System: Psychosocial Challenges and Developmental Difficulties.

PubMed

Taube-Schiff, Marlene; Yufe, Shira; Kastanias, Patti; Weiland, Mary; Sockalingam, Sanjeev

2017-08-01

Bariatric surgery is an evidence-based treatment for severe obesity; however, the unique developmental and psychosocial needs of young adults often complicate care and, as yet, are not well understood. We sought to identify themes in young adult patients undergoing bariatric surgery regarding: 1) the psychosocial experiences of obese young adults (18 to 24) seeking bariatric surgery; 2) the experiences during the preoperative bariatric surgery process and 3) the postoperative experiences of young adult patients. In-depth, semistructured individual interviews were conducted with 13 young adult bariatric patients who were seeking or had undergone bariatric surgery within the past 5 years. Interviews were analyzed using a qualitative methodology. We found the following themes in our analyses: 1) the impact of relationships (with families and healthcare providers) on the bariatric healthcare experience; 2) preoperative experiences by young adults prior to undergoing surgery and 3) postoperative reflections and challenges experienced by young adult patients. Results revealed that patients' experiences appear to encompass impact on familial relationships, needs sought to be fulfilled by healthcare providers, and various preoperative and postoperative psychosocial concerns. By understanding the experiences of young adults, healthcare providers might be able to provide better care for these patients. Copyright © 2017 Diabetes Canada. Published by Elsevier Inc. All rights reserved.

Ultraviolet luminosity density of the universe during the epoch of reionization.

PubMed

Mitchell-Wynne, Ketron; Cooray, Asantha; Gong, Yan; Ashby, Matthew; Dolch, Timothy; Ferguson, Henry; Finkelstein, Steven; Grogin, Norman; Kocevski, Dale; Koekemoer, Anton; Primack, Joel; Smidt, Joseph

2015-09-08

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be log ρ(UV) = 27.4(+0.2)(-1.2) ergs(-1) Hz(-1) Mpc(-3) (1σ). This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaurov, Alexander A., E-mail: kaurov@uchicago.edu

We explore a time-dependent energy dissipation of the energetic electrons in the inhomogeneous intergalactic medium (IGM) during the epoch of cosmic reionization. In addition to the atomic processes, we take into account the inverse Compton (IC) scattering of the electrons on the cosmic microwave background photons, which is the dominant channel of energy loss for electrons with energies above a few MeV. We show that: (1) the effect on the IGM has both local (atomic processes) and non-local (IC radiation) components; (2) the energy distribution between hydrogen and helium ionizations depends on the initial energy of an electron; (3) themore » local baryon overdensity significantly affects the fractions of energy distributed in each channel; and (4) the relativistic effect of the atomic cross-section becomes important during the epoch of cosmic reionization. We release our code as open source for further modification by the community.« less

A Lyman Break Galaxy in the Epoch of Reionization from Hubble Space Telescope (HST) Grism Spectroscopy

NASA Technical Reports Server (NTRS)

Rhoads, James E.; Malhotra, Sangeeta; Stern, Daniel K.; Gardner, Jonathan P.; Dickinson, Mark; Pirzkal, Norbert; Spinrad, Hyron; Reddy, Naveen; Dey, Arjun; Hathi, Nimish;

Brute-force mapmaking with compact interferometers: a MITEoR northern sky map from 128 to 175 MHz

NASA Astrophysics Data System (ADS)

Zheng, H.; Tegmark, M.; Dillon, J. S.; Liu, A.; Neben, A. R.; Tribiano, S. M.; Bradley, R. F.; Buza, V.; Ewall-Wice, A.; Gharibyan, H.; Hickish, J.; Kunz, E.; Losh, J.; Lutomirski, A.; Morgan, E.; Narayanan, S.; Perko, A.; Rosner, D.; Sanchez, N.; Schutz, K.; Valdez, M.; Villasenor, J.; Yang, H.; Zarb Adami, K.; Zelko, I.; Zheng, K.

2017-03-01

We present a new method for interferometric imaging that is ideal for the large fields of view and compact arrays common in 21 cm cosmology. We first demonstrate the method with the simulations for two very different low-frequency interferometers, the Murchison Widefield Array and the MIT Epoch of Reionization (MITEoR) experiment. We then apply the method to the MITEoR data set collected in 2013 July to obtain the first northern sky map from 128 to 175 MHz at ∼2° resolution and find an overall spectral index of -2.73 ± 0.11. The success of this imaging method bodes well for upcoming compact redundant low-frequency arrays such as Hydrogen Epoch of Reionization Array. Both the MITEoR interferometric data and the 150 MHz sky map are available at http://space.mit.edu/home/tegmark/omniscope.html.

Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fialkov, A.; Loeb, A., E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

2016-05-01

The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we showmore » that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.« less

Studying Lyman-alpha escape and reionization in Green Pea galaxies

NASA Astrophysics Data System (ADS)

Yang, Huan; Malhotra, Sangeeta; Rhoads, James E.; Gronke, Max; Leitherer, Claus; Wofford, Aida; Dijkstra, Mark

2017-01-01

Green Pea galaxies are low-redshift galaxies with extreme [OIII]5007 emission line. We built the first statistical sample of Green Peas observed by HST/COS and used them as analogs of high-z Lyman-alpha emitters to study Ly-alpha escape and Ly-alpha sizes. Using the HST/COS 2D spectra, we found that Ly-alpha sizes of Green Peas are larger than the UV continuum sizes. We found many correlations between Ly-alpha escape fraction and galactic properties -- dust extinction, Ly-alpha kinematic features, [OIII]/[OII] ratio, and gas outflow velocities. We fit an empirical relation to predict Ly-alpha escape fraction from dust extinction and Ly-alpha red-peak velocity. In the JWST era, we can use this relation to derive the IGM HI column density along the line of sight of each high-z Ly-alpha emitter and probe the reionization process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, David F.; Aguirre, James E.; Parsons, Aaron R.

Experiments aimed at detecting highly-redshifted 21 cm emission from the epoch of reionization (EoR) are plagued by the contamination of foreground emission. A potentially important source of contaminating foregrounds may be Faraday-rotated, polarized emission, which leaks into the estimate of the intrinsically unpolarized EoR signal. While these foregrounds' intrinsic polarization may not be problematic, the spectral structure introduced by the Faraday rotation could be. To better understand and characterize these effects, we present a simulation of the polarized sky between 120 and 180 MHz. We compute a single visibility, and estimate the three-dimensional power spectrum from that visibility using themore » delay spectrum approach presented in Parsons et al. Using the Donald C. Backer Precision Array to Probe the Epoch of Reionization as an example instrument, we show the expected leakage into the unpolarized power spectrum to be several orders of magnitude above the expected 21 cm EoR signal.« less

Health-Seeking Challenges Among Homeless Youth

PubMed Central

Hudson, Angela L.; Nyamathi, Adeline; Greengold, Barbara; Slagle, Alexandra; Koniak-Griffin, Deborah; Khalilifard, Farinaz; Getzoff, Daniel

2010-01-01

Background Approximately 1.5 to 2 million homeless young persons live on the streets in the United States. With the current economic situation, research is needed on quality of services geared toward homeless young adults. Objectives The objective of this study was to explore homeless young adults' perspectives on barriers and facilitators of health-care-seeking behavior and their perspectives on improving existing programs for homeless persons. Methods This article is a descriptive qualitative study using focus groups, with a purposeful sample of 24 homeless drug-using young adults. Results Identified themes were failing access to care based on perceived structural barriers (limited clinic sites, limited hours of operation, priority health conditions, and long wait times) and social barriers (perception of discrimination by uncaring professionals, law enforcement, and society in general). Discussion Results provide insight into programmatic and agency resources that facilitate health-seeking behaviors among homeless young adults and include implications for more research with providers of homeless health and social services. PMID:20404776

Between modern and traditional values: Informal mental health help-seeking attitudes according to Israeli Arab women, primary care patients and their providers.

PubMed

Ayalon, Liat; Karkabi, Khaled; Bleichman, Igor; Fleischmann, Silvia; Goldfracht, Margalit

2015-06-01

Israeli Arab women under-utilize mental health services. The present study evaluated the use of alternative services for dealing with depression and anxiety among Israeli Arab women and primary care providers. Four focus groups with primary care patients and two focus groups with primary care providers were conducted. Constant comparisons were employed in order to identify major themes related to informal help-seeking behaviors. Three informal help-seeking behaviors were identified: (a) social support, divided into extended family and neighbors versus nuclear family and close friends; (b) religiosity, divided into inner, direct practices and beliefs versus externally mediated ones; and (c) self-help techniques, such as engagement in activities and distancing oneself from the situation. Both social support and religiosity were viewed with ambivalence by primary care patients and providers. The findings suggest that the Arab population in Israel might be lacking informal sources of support at times of mental health needs. © The Author(s) 2014.

Contrasting beliefs about screening for mental disorders among UK military personnel returning from deployment to Afghanistan.

PubMed

Keeling, M; Knight, T; Sharp, D; Fertout, M; Greenberg, N; Chesnokov, M; Rona, R J

2012-12-01

The objective of the study was to elicit beliefs and experiences of the value of a screening programme for mental illness among UK military personnel. Three months after returning from Afghanistan 21 army personnel participated in a qualitative study about mental health screening. One-to-one interviews were conducted and recorded. Data-driven thematic analysis was used. Researchers identified master themes represented by extracts of text from the 21 complete transcripts. Participants made positive remarks on the advantages of screening. Noted barriers to seeking help included: unwillingness to receive advice, a wish to deal with any problems themselves and a belief that military personnel should be strong enough to cope with any difficulties. Participants believed that overcoming barriers to participating in screening and seeking help would be best achieved by making screening compulsory. Although respondents were positive about a screening programme for mental illness, the barriers to seeking help for mental illness appear deep rooted and reinforced by the value ascribed to hardiness.

'Stress, anger, fear and injustice': An international qualitative survey of women's experiences planning a vaginal breech birth.

PubMed

Petrovska, Karolina; Watts, Nicole P; Catling, Christine; Bisits, Andrew; Homer, Caroline Se

2017-01-01

the outcomes of the Term Breech Trial had a profound impact on women's options for breech birth, with caesarean section now seen as the default method for managing breech birth by many clinicians. Despite this, the demand for planned vaginal breech birth from women does exist. This study aimed to examine the experiences of women who sought a vaginal breech birth to increase understanding as to how to care for women seeking this birth option. an electronic survey was distributed to women online via social media. The survey consisted of qualitative and quantitative questions, with the qualitative data being the focus of this paper. Open ended questions sought information on the ways in which woman sourced a clinician skilled in vaginal breech birth and the level of support and quality of information provided from clinicians regarding vaginal breech birth. Thematic analysis was used to analyse and code the qualitative data into major themes. in total, 204 women from over seven countries responded to the survey. Written responses to the open ended questions were categorised into seven themes: Seeking the chance to try for a VBB; Encountering coercion and fear; Putting the birth before the baby?; Dealing with emotional wounds; Searching for information and support; Traveling across boundaries; Overcoming obstacles in the system. for women seeking vaginal breech birth, limited system and clinical support can impede access to balanced information and options for care. Recognition of existing evidence on the safety of vaginal breech birth, as well as the presence of clinical guidelines that support it, may assist in promoting vaginal breech birth as a legitimate option that should be available to women. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum

NASA Astrophysics Data System (ADS)

Majumdar, Suman; Pritchard, Jonathan R.; Mondal, Rajesh; Watkinson, Catherine A.; Bharadwaj, Somnath; Mellema, Garrelt

2018-05-01

The epoch of reionization (EoR) 21-cm signal is expected to be highly non-Gaussian in nature and this non-Gaussianity is also expected to evolve with the progressing state of reionization. Therefore the signal will be correlated between different Fourier modes (k). The power spectrum will not be able capture this correlation in the signal. We use a higher order estimator - the bispectrum - to quantify this evolving non-Gaussianity. We study the bispectrum using an ensemble of simulated 21-cm signal and with a large variety of k triangles. We observe two competing sources driving the non-Gaussianity in the signal: fluctuations in the neutral fraction (x_{H I}) field and fluctuations in the matter density field. We find that the non-Gaussian contribution from these two sources varies, depending on the stage of reionization and on which k modes are being studied. We show that the sign of the bispectrum works as a unique marker to identify which among these two components is driving the non-Gaussianity. We propose that the sign change in the bispectrum, when plotted as a function of triangle configuration cos θ and at a certain stage of the EoR can be used as a confirmative test for the detection of the 21-cm signal. We also propose a new consolidated way to visualize the signal evolution (with evolving \\bar{x}_{H I} or redshift), through the trajectories of the signal in a power spectrum and equilateral bispectrum i.e. P(k) - B(k, k, k) space.

Galactic wind X-ray heating of the intergalactic medium during the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Meiksin, Avery; Khochfar, Sadegh; Paardekooper, Jan-Pieter; Dalla Vecchia, Claudio; Kohn, Saul

2017-11-01

The diffuse soft X-ray emissivity from galactic winds is computed during the Epoch of Reionization (EoR). We consider two analytic models, a pressure-driven wind and a superbubble model, and a 3D cosmological simulation including gas dynamics from the First Billion Years (FiBY) project. The analytic models are normalized to match the diffuse X-ray emissivity of star-forming galaxies in the nearby Universe. The cosmological simulation uses physically motivated star formation and wind prescriptions, and includes radiative transfer corrections. The models and the simulation all are found to produce sufficient heating of the intergalactic medium to be detectable by current and planned radio facilities through 21 cm measurements during the EoR. While the analytic models predict a 21 cm emission signal relative to the cosmic microwave backgroundsets in by ztrans ≃ 8-10, the predicted signal in the FiBY simulation remains in absorption until reionization completes. The 21 cm absorption differential brightness temperature reaches a minimum of ΔT ≃ -130 to -200 mK, depending on model. Allowing for additional heat from high-mass X-ray binaries pushes the transition to emission to ztrans ≃ 10-12, with shallower absorption signatures having a minimum of ΔT ≃ -110 to -140 mK. The 21 cm signal may be a means of distinguishing between the wind models, with the superbubble model favouring earlier reheating. While an early transition to emission may indicate X-ray binaries dominate the reheating, a transition to emission as early as ztrans > 12 would suggest the presence of additional heat sources.

LSST and the Epoch of Reionization Experiments

NASA Astrophysics Data System (ADS)

Ivezić, Željko

2018-05-01

The Large Synoptic Survey Telescope (LSST), a next generation astronomical survey, sited on Cerro Pachon in Chile, will provide an unprecedented amount of imaging data for studies of the faint optical sky. The LSST system includes an 8.4m (6.7m effective) primary mirror and a 3.2 Gigapixel camera with a 9.6 sq. deg. field of view. This system will enable about 10,000 sq. deg. of sky to be covered twice per night, every three to four nights on average, with typical 5-sigma depth for point sources of r = 24.5 (AB). With over 800 observations in the ugrizy bands over a 10-year period, these data will enable coadded images reaching r = 27.5 (about 5 magnitudes deeper than SDSS) as well as studies of faint time-domain astronomy. The measured properties of newly discovered and known astrometric and photometric transients will be publicly reported within 60 sec after closing the shutter. The resulting hundreds of petabytes of imaging data for about 40 billion objects will be used for scientific investigations ranging from the properties of near-Earth asteroids to characterizations of dark matter and dark energy. For example, simulations estimate that LSST will discover about 1,000 quasars at redshifts exceeding 7; this sample will place tight constraints on the cosmic environment at the end of the reionization epoch. In addition to a brief introduction to LSST, I review the value of LSST data in support of epoch of reionization experiments and discuss how international participants can join LSST.

Origins Space Telescope: Cosmology and Reionization

NASA Astrophysics Data System (ADS)

Vieira, Joaquin D.; Origins Space Telescope Study Team

2017-01-01

The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its imagers and spectrographs will enable a variety of surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu.A core science goal of the OST mission is to study the the cosmological history of star, galaxy, and structure formation into the epoch of reionization (EoR). OST will probe the birth of galaxies through warm molecular hydrogen emission during the cosmic dark ages. Utilizing the unique power of the infrared fine-structure emission lines, OST will trace the rise of metals from the first galaxies until today. It will quantify the dust enrichment history of the Universe, uncover its composition and physical conditions, reveal the first cosmic sources of dust, and probe the properties of the earliest star formation. OST will provide a detailed astrophysical probe into the condition of the intergalactic medium at z > 6 and the galaxies which dominate the epoch of reionization.

Origins Space Telescope: Cosmology and Reionization

NASA Astrophysics Data System (ADS)

Vieira, Joaquin Daniel; Origins Space Telescope

2018-01-01

The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its imagers and spectrographs will enable a variety of surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu.A core science goal of the OST mission is to study the the cosmological history of star, galaxy, and structure formation into the epoch of reionization (EoR). OST will probe the birth of galaxies through warm molecular hydrogen emission during the cosmic dark ages. Utilizing the unique power of the infrared fine-structure emission lines, OST will trace the rise of metals from the first galaxies until today. It will quantify the dust enrichment history of the Universe, uncover its composition and physical conditions, reveal the first cosmic sources of dust, and probe the properties of the earliest star formation. OST will provide a detailed astrophysical probe into the condition of the intergalactic medium at z > 6 and the galaxies which dominate the epoch of reionization.

Measuring the Largest Angular Scale CMB B-mode Polarization with Galactic Foregrounds on a Cut Sky

NASA Astrophysics Data System (ADS)

Watts, Duncan J.; Larson, David; Marriage, Tobias A.; Abitbol, Maximilian H.; Appel, John W.; Bennett, Charles L.; Chuss, David T.; Eimer, Joseph R.; Essinger-Hileman, Thomas; Miller, Nathan J.; Rostem, Karwan; Wollack, Edward J.

2015-12-01

We consider the effectiveness of foreground cleaning in the recovery of Cosmic Microwave Background (CMB) polarization sourced by gravitational waves for tensor-to-scalar ratios in the range 0\\lt r\\lt 0.1. Using the planned survey area, frequency bands, and sensitivity of the Cosmology Large Angular Scale Surveyor (CLASS), we simulate maps of Stokes Q and U parameters at 40, 90, 150, and 220 GHz, including realistic models of the CMB, diffuse Galactic thermal dust and synchrotron foregrounds, and Gaussian white noise. We use linear combinations (LCs) of the simulated multifrequency data to obtain maximum likelihood estimates of r, the relative scalar amplitude s, and LC coefficients. We find that for 10,000 simulations of a CLASS-like experiment using only measurements of the reionization peak ({\\ell }≤slant 23), there is a 95% C.L. upper limit of r\\lt 0.017 in the case of no primordial gravitational waves. For simulations with r=0.01, we recover at 68% C.L. r={0.012}-0.006+0.011. The reionization peak corresponds to a fraction of the multipole moments probed by CLASS, and simulations including 30≤slant {\\ell }≤slant 100 further improve our upper limits to r\\lt 0.008 at 95% C.L. (r={0.010}-0.004+0.004 for primordial gravitational waves with r = 0.01). In addition to decreasing the current upper bound on r by an order of magnitude, these foreground-cleaned low multipole data will achieve a cosmic variance limited measurement of the E-mode polarization’s reionization peak.

The Lyman continuum escape fraction of low mass star-forming galaxies at z~1.

NASA Astrophysics Data System (ADS)

Rutkowski, Michael J.; Scarlata, Claudia; Haardt, Francesco; Siana, Brian D.; Rafelski, Marc; Henry, Alaina L.; Hayes, Matthew; Salvato, Mara; Pahl, Anthony; Mehta, Vihang; Beck, Melanie; Malkan, Matthew Arnold; Teplitz, Harry I.

2016-01-01

Star-forming galaxies (SFGs) in the high redshift universe (z>6) are believed to ionize neutral hydrogen in the intergalactic medium during the epoch of reionization. We tested this assumption by studying likely analogs of these SFGs in archival HST grism spectroscopy with GALEX UV and ground-based optical images at the redshift range in which we can directly measure the rest-frame Lyman continuum (λ<912Å, LyC) emission. We selected ~1400 SFGs for study on the presence of strong Hα emission and strongly selected against those SFGs whose GALEX FUV photometry could be contaminated by low redshift interlopers along the line of sight to produce a sample of ~600 z~1 SFGs. We made no unambiguous detection of escaping Lyman continuum radiation in individual galaxies in this sample, and stacked the individual non-detections in order to constrain the absolute Lyman continuum escape fraction, fesc<2% (3σ). We sub-divided this sample and stacked SFGs to measure upper limits to fesc with respect to stellar mass,luminosity and relative orientation. For z~1 high Hα equivalent width (EW>200Å) SFGs, we found for the first time an upper limit to fesc<9%. We discuss the implications of these limits for the ionizing emissivity of high redshift SFGs during the epoch of reionization. We conclude that reionization by SFGs is only marginally consistent with independent Planck observations of the CMB electron scattering opacity unless the LyC escape fraction of SFGs increases with redshift and an unobserved population of faint (MUV<-13 AB) SFGs contributes significantly to the UV background.

The concerted impact of galaxies and QSOs on the ionization and thermal state of the intergalactic medium

NASA Astrophysics Data System (ADS)

Kakiichi, Koki; Graziani, Luca; Ciardi, Benedetta; Meiksin, Avery; Compostella, Michele; Eide, Marius B.; Zaroubi, Saleem

2017-07-01

We present a detailed analysis of the ionization and thermal structure of the intergalactic medium (IGM) around a high-redshift (z = 10) QSO, using a large suite of cosmological, multifrequency radiative transfer simulations, exploring the contribution from galaxies as well as the QSO, and the effect of X-rays and secondary ionization. We show that in high-z QSO environments both the central QSO and the surrounding galaxies concertedly control the reionization morphology of hydrogen and helium and have a non-linear impact on the thermal structure of the IGM. A QSO imprints a distinctive morphology on H II regions if its total ionizing photon budget exceeds that of the surrounding galaxies since the onset of hydrogen reionization; otherwise, the morphology shows little difference from that of H II regions produced only by galaxies. In addition, the spectral shape of the collective radiation field from galaxies and QSOs controls the thickness of the I-fronts. While a UV-obscured QSO can broaden the I-front, the contribution from other UV sources, either galaxies or unobscured QSOs, is sufficient to maintain a sharp I-front. X-ray photons from the QSO are responsible for a prominent extended tail of partial ionization ahead of the I-front. QSOs leave a unique imprint on the morphology of He II/He III regions. We suggest that, while the physical state of the IGM is modified by QSOs, the most direct test to understand the role of galaxies and QSOs during reionization is to perform galaxy surveys in a region of sky imaged by 21 cm tomography.

RELICS of the Cosmic Dawn

NASA Astrophysics Data System (ADS)

Bradac, Marusa; Coe, Dan; Huang, Kuang-Han; Salmon, Brett; Hoag, Austin; Bradley, Larry; Ryan, Russell; Dawson, Will; Zitrin, Adi; Jones, Christine; Sharon, Keren; Trentu, Michele; Stark, Daniel; Bouwens, Rychard; Oesch, Pascal; Lam, Daniel; Patricia Carasco Nunez, Daniela; Paterno-Mahler, Rachel; Strait, Victoria

2017-10-01

When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and epoch of reionization? Recent observations indicate at least two critical puzzles in these studies. (1) First galaxies might have started forming stars earlier than previously thought (<400Myr after the Big Bang). (2) It is still unclear what is their star formation history and whether these galaxies can reionize the Universe. Accurate knowledge of stellar masses, ages, and star formation rates at this epoch requires measuring both rest-frame UV and optical light, which only Spitzer and HST can probe at z 6-11 for a large enough sample of typical galaxies. To address this cosmic puzzle, we propose Spitzer imaging of the fields behind the most powerful cosmic telescopes selected using HST, Spitzer, and Planck data from the RELICS and SRELICS programs (Reionization Lensing Cluster Survey; 41 clusters, 190 HST orbits, 550 Spitzer hours). This proposal will be a valuable Legacy complement to the existing IRAC deep surveys, and it will open up a new parameter space by probing the ordinary yet magnified population with much improved sample variance. The program will allow us to study stellar properties of a large number, 20 galaxies at z 6-11. Deep Spitzer data will be crucial to unambiguously measure their stellar properties (age, SFR, M*). Finally this proposal is a unique opportunity to establish the presence (or absence) of an unusually early established stellar population, as was recently observed in MACS1149JD at z 9. If confirmed, this result will require a paradigm shift in our understanding of the earliest star formation.

RELICS of the Cosmic Dawn

NASA Astrophysics Data System (ADS)

Bradac, Marusa; Coe, Dan; Huang, Kuang-Han; Salmon, Brett; Hoag, Austin; Bradley, Larry; Ryan, Russell; Dawson, Will; Zitrin, Adi; Jones, Christine; Sharon, Keren; Trenti, Michele; Stark, Daniel; Bouwens, Rychard; Oesch, Pascal; Lam, Daniel; Carrasco Nunez, Daniela Patricia

2017-04-01

When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and epoch of reionization? Recent observations indicate at least two critical puzzles in these studies. (1) First galaxies might have started forming stars earlier than previously thought (<400Myr after the Big Bang). (2) It is still unclear what is their star formation history and whether these galaxies can reionize the Universe. Accurate knowledge of stellar masses, ages, and star formation rates at this epoch requires measuring both rest-frame UV and optical light, which only Spitzer and HST can probe at z 6-11 for a large enough sample of typical galaxies. To address this cosmic puzzle, we propose Spitzer imaging of the fields behind 3 most powerful cosmic telescopes selected using HST, Spitzer, and Planck data from the RELICS and SRELICS programs (Reionization Lensing Cluster Survey; 41 clusters, 190 HST orbits, 390 Spitzer hours). This proposal will be a valuable Legacy complement to the existing IRAC deep surveys, and it will open up a new parameter space by probing the ordinary yet magnified population with much improved sample variance. The program will allow us to study stellar properties of a large number, 30 galaxies at z 6-11. Deep Spitzer data will be crucial to unambiguously measure their stellar properties (age, SFR, M*). Finally this proposal will establish the presence (or absence) of an unusually early established stellar population, as was recently observed in MACS1149JD at z 9. If confirmed in a larger sample, this result will require a paradigm shift in our understanding of the earliest star formation.

Fabrication of FORTIS

NASA Astrophysics Data System (ADS)

McCandliss, Stephan R.; Fleming, Brian; Kaiser, Mary Elizabeth; Kruk, Jeffrey; Feldman, Paul D.; Kutyrev, Alexander S.; Li, Mary J.; Goodwin, Phillip A.; Rapchun, David; Lyness, Eric; Brown, Ari D.; Moseley, Harvey; Siegmund, Oswald; Vallerga, John

2010-07-01

The Johns Hopkins University sounding rocket group is building the Far-ultraviolet Off Rowland-circle Telescope for Imaging and Spectroscopy (FORTIS), which is a Gregorian telescope with rulings on the secondary mirror. FORTIS will be launched on a sounding rocket from White Sand Missile Range to study the relationship between Lyman alpha escape and the local gas-to-dust ratio in star forming galaxies with non-zero redshifts. It is designed to acquire images of a 30' x 30' field and provide fully redundant "on-the-fly" spectral acquisition of 43 separate targets in the field with a bandpass of 900 - 1800 Angstroms. FORTIS is an enabling scientific and technical activity for future cutting edge far- and near-uv survey missions seeking to: search for Lyman continuum radiation leaking from star forming galaxies, determine the epoch of He II reionization and characterize baryon acoustic oscillations using the Lyman forest. In addition to the high efficiency "two bounce" dual-order spectro-telescope design, FORTIS incorporates a number of innovative technologies including: an image dissecting microshutter array developed by GSFC; a large area (~ 45 mm x 170 mm) microchannel plate detector with central imaging and "outrigger" spectral channels provided by Sensor Sciences; and an autonomous targeting microprocessor incorporating commercially available field programable gate arrays. We discuss progress to date in developing our pathfinder instrument.

Insights into the Experiences of Treatment for An Eating Disorder in Men: A Qualitative Study of Autobiographies

PubMed Central

Thapliyal, Priyanka; Mitchison, Deborah; Hay, Phillipa

2017-01-01

Eating disorders are increasingly recognized as a problem for men but help-seeking is low and little is known about their treatment experiences. This paper sought to determine the treatment experiences of men who have suffered from an eating disorder using autobiographical data. Inclusion criteria were autobiographies of men who had experienced an eating disorder and sought any form of treatment for this, written in the English language, published between 1995 and 2015, and available for purchase in 2016. The search resulted in six books that were thematically analyzed. Analysis of data resulted in two broad themes (1. Positive experiences; 2. Negative experiences) with sub-themes. With regards to the first theme, factors such as concern of staff members, therapist’s expertise (in treating eating disorders in men), and a collaborative treatment approach were considered favorable for treatment. In contrast to the first theme, apathy of staff members, the authors’ own negative preconceptions, treatment providers being perceived as prioritizing financial concerns, perceived as incompetent and judgmental behavior of therapist(s), and time limitations of sessions were considered unfavorable treatment experiences. In this study, the perceived success of treatment depended on therapist’s features and the form of treatment provided. Further research examining these is indicated. PMID:28621727

The workers role in knowledge management and sustainability policies.

PubMed

Bolis, Ivan; Brunoro, Claudio; Sznelwar, Laerte Idal

2012-01-01

Based on the concepts of sustainability and knowledge management, this article seeks to identify points of contact between the two themes through an exploratory study of existing literature. The first objective is to find, in international literature, the largest number of papers jointly related to the theme of knowledge management and sustainability. In these documents, the authors looked at the kind of relationship existing between the two themes and what the benefits introduced in organizations are. Based on an ergonomic point of view, the second objective of this article is to analyze the role of the worker (whether at the strategic or operational level) and his importance in this context. The results demonstrate that there is very little literature that addresses the two themes together. The few papers found, however, can be said to show the many advantages of introducing sustainability policies supported by adequate knowledge management. Very little has been studied with regards to the role of workers, which could be interpreted as meaning that little importance is given to the proactive role they may play. On the other hand, there is a high potential for future research in these areas, based on the high level of consideration of workers in knowledge management and sustainability literature, as well as in literature in the areas of ergonomics and sociology.

A Community-Engaged Research Approach to Improve Mental Health Among Latina Immigrants: ALMA Photovoice.

PubMed

Perez, Georgina; Della Valle, Pamela; Paraghamian, Sarah; Page, Rachel; Ochoa, Janet; Palomo, Fabiana; Suarez, Emilia; Thrasher, Angela; Tran, Anh N; Corbie-Smith, Giselle

2016-05-01

Recent Latina immigrants are at increased risk of poor mental health due to stressors associated with adapting to life in the United States. Existing social and health care policies often do not adequately address the mental health concerns of new Latino populations. Amigas Latinas Motivando el Alma, a community-partnered research project, seeks to improve immigrant Latinas' mental health outcomes. Using Photovoice methodology, promotoras (lay health advisors) reflected on community factors affecting mental health through photography and guided discussion. Discussions were audio-recorded, transcribed, and coded using content analysis to identify salient themes. Promotoras reviewed codes to develop themes that they presented in community forums to reach local policy makers and to increase community awareness. These forums included an exhibit of the promotoras' photographs and discussion of action steps to address community concerns. Themes included transitioning to life in the United States, parenting, education, and combating racism. Nearly 150 stakeholders attended the community forums and proposed responses to promotoras' photographic themes. Our findings suggest that Photovoice provides an opportunity for Latinas and the larger community to identify issues that they find most important and to explore avenues for action and change by creating sustainable partnerships between the community and forum attendees. © 2015 Society for Public Health Education.

Male nurses and chemical dependency: masterminding the nursing environment.

PubMed

Dittman, Patricia Welch

2008-01-01

Florida men in nursing who are chemically dependent represent a greater percentage of the total number of male nurses than female nurses who are chemically dependent. This study identifies characteristics of 9 men who completed the Florida Intervention Project for Nurses. All participants were interviewed independently and data were analyzed to determine common themes in their behaviors and relationships and how they successfully manipulated professional nursing systems to remain professionally active for prolonged period of time while impaired. A model of caring for nurses with professional impairment graphically depicted the interaction of 2 overarching themes of person and profession. The person theme had 3 subthemes of predetermined risk, altered values, and sensation-seeking behaviors. The profession theme had 6 subthemes of masterminding, professional heteronomy, getting caught, rehabilitation, spirituality, and the nurse becoming the nursed. Findings imply that chemical dependency among male nurses starts in childhood in an abusive family environment and continues throughout the educational process and into the work environment. Findings supporting diversion success include a lack of awareness of the signs and symptoms of impairment by supervisors, poor compliance to drug control procedures, and a common acceptance by peers that impaired men are clinically competent and clinical leaders. When these 3 situations are present, there is greater success in masterminding daily events to maintain undetected drug access.

Understanding the Health Needs and Barriers to Seeking Health Care of Veteran Students in the Community.

PubMed

Misra-Hebert, Anita D; Santurri, Laura; DeChant, Richard; Watts, Brook; Rothberg, Michael; Sehgal, Ashwini R; Aron, David C

2015-08-01

Access to care at Veterans Affairs facilities may be limited by long wait times; however, additional barriers may prevent US military veterans from seeking help at all. We sought to understand the health needs of veterans in the community to identify possible barriers to health-seeking behavior. Focus groups were conducted with veteran students at a community college until thematic saturation was reached. Qualitative data analysis involved both an inductive content analysis approach and deductive elements. A total of 17 veteran students participated in 6 separate focus groups. Health needs affecting health-seeking behavior were identified. Themes included lack of motivation to improve health, concern about social exclusion and stigma, social interactions and behavior, limited access to affordable and convenient health care, unmet basic needs for self and family, and academics competing with health needs. Veterans face a range of personal, societal, and logistical barriers to accessing care. In addition to decreasing wait times for appointments, efforts to improve the transition to civilian life; reduce stigma; and offer assistance related to work, housing, and convenient access to health care may improve health in veteran students.

Midlife crisis perceptions, experiences, help-seeking, and needs among multi-ethnic malaysian women.

PubMed

Wong, Li Ping; Awang, Halimah; Jani, Rohana

2012-01-01

In the present study, researchers explored attitudes toward midlife crises, experience with midlife crises, help-seeking, and needs among multi-ethnic Malaysian women. A total of 14 focus group discussions were conducted with 89 Malaysian women of different ages and socioeconomic backgrounds. Women expressed concern over physical aging and decline in their physical functional health. Having a midlife crisis was frequently reported. Issues that were frequently reported to trigger a midlife crisis, such as empty nest syndrome, impact of aging on sexual and reproductive function, extended parenthood, caring for aging or ill parents, and career challenges were noted by the study participants (listed here in order of most to least frequently reporting of these themes across the group discussions). Overall, these issues were associated with attitudes about aging. A comparatively less open attitude toward sexual attitudes and help-seeking for sexual problems were found among the Malay and Indian women. This may imply that intervention to increase positive attitudes concerning both sexuality and help-seeking intentions should be culturally specific. The use of religious coping for comfort and consolation was frequently reported; therefore, those providing midlife crisis prevention and intervention programs should consider involving faith-based interventions in the Malaysian setting.

Understanding the Health Needs and Barriers to Seeking Health Care of Veteran Students in the Community

PubMed Central

Misra-Hebert, Anita D.; Santurri, Laura; DeChant, Richard; Watts, Brook; Rothberg, Michael; Sehgal, Ashwini R.; Aron, David C.

2015-01-01

Objectives Access to care at Veterans Affairs facilities may be limited by long wait times; however, additional barriers may prevent US military veterans from seeking help at all. We sought to understand the health needs of veterans in the community to identify possible barriers to health-seeking behavior. Methods Focus groups were conducted with veteran students at a community college until thematic saturation was reached. Qualitative data analysis involved both an inductive content analysis approach and deductive elements. Results A total of 17 veteran students participated in 6 separate focus groups. Health needs affecting health-seeking behavior were identified. Themes included lack of motivation to improve health, concern about social exclusion and stigma, social interactions and behavior, limited access to affordable and convenient health care, unmet basic needs for self and family, and academics competing with health needs. Conclusions Veterans face a range of personal, societal, and logistical barriers to accessing care. In addition to decreasing wait times for appointments, efforts to improve the transition to civilian life, reduce stigma, and offer assistance related to work, housing, and convenient access to health care may improve health in veteran students. PMID:26280777

'The bloke can be a bit hazy about what's going on': men and cross-border reproductive treatment.

PubMed

Hudson, Nicky; Culley, Lorraine

2013-09-01

While social science research has begun to demonstrate the significant impact of infertility and involuntary childlessness for men, far fewer studies have specifically explored the male experience of, or men's involvement in, infertility treatment-seeking and there are few published studies which specifically describe men's experiences with cross-border reproduction. This paper presents data from the first UK study of transnational treatment-seeking and specifically explores men's involvement in this process. Data from interviews with 10 men and 34 women who were seeking treatment abroad are organized according to three themes: 'going along with it'; 'being a rock'; and 'doing their bit'. The paper argues that gender is an important aspect of the cross-border treatment experience and that both traditional and emergent gender identities are expressed in the process of treatment-seeking. Healthcare providers need to actively explore men's perspectives of the treatment process in all locations, to improve quality of care by reducing men's feelings of marginalization and enhancing their experience of treatment, especially but not exclusively, around the issue of semen collection. Copyright © 2013 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

A Qualitative Study on Coping Strategies among Women from Food Insecurity Households in Selangor and Negeri Sembilan.

PubMed

Norhasmah, S; Zalilah, M S; Mohd Nasir, M T; Kandiah, M; Asnarulkhadi, A S

2010-04-01

Understanding the experiences of household food insecurity is essential for better measurement and assessment of its nutritional, physical and psychological consequences. This qualitative study explored coping strategies and their perceived severity in relation to household food insecurity. Women (n=57; 20-50 years old) from rural and urban areas in Selangor and Negeri Sembilan participated in this study. These women were interviewed using a semi-structured questionnaire. The questionnaire was divided into two parts, that is, demographic and socio-economic information and women's experiences of coping with household food insecurity. Women were chosen since they were primarily responsible for food acquisition and preparation for the all household members. Thematic analysis was utilized in data analysis. Thematic analysis is a method for identifying, analysing and reporting patterns and themes of the qualitative data. Themes capture something important related to the study objectives and describe an integrating as well as relational idea from the data. Results showed that households displayed a variety of non-food related coping strategies and food-related coping strategies. Women's descriptions of non-food related coping strategies to food insecurity were categorised into five themes i.e. cloth purchasing behaviors, reduce school-going children's expenditure, delay the payment of bills, adjust lifestyle and increase cash and income earning. Food related coping strategies were categorised into four themes i.e. food stretching, food rationing, food seeking and food anxiety. Food stretching is a strategy of food insecurity that affects the quality of diet. Food rationing comprises coping strategies of food insecurity related to the quantity of food available for household's consumption. Food seeking is a strategy of acquiring food through socially unacceptable ways and food anxiety is a strategy that indicates households allocating money to buy staple food in order to prevent food insecurity. Each coping strategy showed a different level of perceived severity, that is, less severe, quite severe, severe and very severe. In conclusion, the qualitative data provide valuable information for understanding the experiences of food insecurity that can be used as a basis to develop direct indicators that can capture the core behaviours and their level of severity to measure household food insecurity.

Attributions and private theories of mental illness among young adults seeking psychiatric treatment in Nairobi: an interpretive phenomenological analysis.

PubMed

Mbuthia, Judy Wanjiru; Kumar, Manasi; Falkenström, Fredrik; Kuria, Mary Wangari; Othieno, Caleb Joseph

2018-01-01

Mental illness affects every segment of population including young adults. The beliefs held by young patients regarding the causes of mental illness impact their treatment-seeking behaviour. It is pertinent to know the commonly held attributions around mental illness so as to effectively provide psychological care, especially in a resource constrained context such as Kenya. This helps in targeting services around issues such as stigma and extending youth-friendly services. Guided by the private theories interview (PTI-P) and attributional framework, individual semi-structured interviews were carried out with ten young adults of ages 18-25 years about their mental health condition for which they were undergoing treatment. Each interview took 30-45 min. We mapped four attributions (locus of control, stability, controllability and stigma) on PTI-P questions. Data was transcribed verbatim to produce transcripts coded using interpretive phenomenological analysis. These codes were then broken down into categories that could be used to understand various attributions. We found PTI-P to be a useful tool and it elicited three key themes: (a) psychosocial triggers of distress (with themes of negative thoughts, emotions around mental health stigma and negative childhood experiences, parents' separation or divorce, death of a loved one etc.), (b) biological conditions and psychopathologies limiting intervention, and (c) preferences and views on treatment. Mapping these themes on our attributional framework, PTI-P themes presented as causal attributions explaining stigma, locus of control dimensions and stability. External factors were mainly ascribed to be the cause of unstable and uncontrollable attributions including persistent negative emotions and thoughts further exacerbating psychological distress. Nine out of the ten participants expressed the need for more intense and supportive therapy. Our study has provided some experiential evidence in understanding how stigma, internal vs external locus of control, stability vs instability attributions play a role in shaping attitudes young people have towards their mental health. Our study points to psychosocial challenges such as stigma, poverty and lack of social support that continue to undermine mental well-being of Kenyan youth. These factors need to be considered when addressing mental health needs of young people in Kenya.

Seeking Help in Domestic Violence Among Muslim Women in Muslim-Majority and Non-Muslim-Majority Countries: A Literature Review.

PubMed

Afrouz, Rojan; Crisp, Beth R; Taket, Ann

2018-01-01

Women from different backgrounds and cultures are at risk of domestic violence. Disclosing the abusive experience and seeking help is not straightforward and easy and might be a complicated and long-term process. Muslim women, like other groups of women, may face various barriers to disclose abusive relationships and for seeking help. Some of the barriers may be common for the majority of Muslim women in different contexts, while others might be related to women's situations and the wider society they live. To identify these barriers and make recommendations for future studies, this article reviews related papers conducted in both Muslim-majority and non-Muslim-majority countries. A critical systematic review of the literature was conducted for identifying Muslim women's barriers in disclosing abuse and seeking help. Twenty-one studies met the inclusion criteria. The main identified barriers are discussed into under four themes: social context, family context, individual factors, and expectations of service providers. Although the researchers tried to investigate various barriers in seeking help, many of them have not focused on structural obstacles. Besides, in many Muslim-majority countries, the issue has not been explored. Therefore, the results of the current article will not apply to those countries. Recommendation for future research comprises more qualitative research compatible with the women's cultures and backgrounds in different societies, focusing more on structural and cultural factors to explore and find women's barriers to seek help.

A meta-summary of qualitative findings on the lived experience among culturally diverse domestic violence survivors.

PubMed

Childress, Saltanat

2013-09-01

This meta-summary study explores, extracts, and summarizes themes from related qualitative studies on the lived experiences and coping mechanisms among culturally diverse domestic violence survivors. Using Sandelowski and Barroso's meta-summary strategy, a systematic literature review of articles published between 1990 and 2010 was conducted using a qualitative approach. Of a total of 802 studies, nine met the study inclusion criteria. This meta-summary of nine studies confirms the recurring themes in primary qualitative studies in the literature that illustrate women's experiences of domestic violence. These themes include (a) the effects of violence, (b) the cyclical nature of violence, (c) normalizing and tolerating violence, (d) the strength and resilience of victims, (e) barriers to help-seeking, and (f) the role of substance use in domestic violence. The review shows key cross-cultural differences in women's perceptions of abuse and the causes and strategies for responding to abuse. The review also reveals the lack of studies on domestic violence among women from Central Asia and the former Soviet Union.

Pediatric to Adult Care Transition: Perspectives of Young Adults With Sickle Cell Disease.

PubMed

Porter, Jerlym S; Wesley, Kimberly M; Zhao, Mimi S; Rupff, Rebecca J; Hankins, Jane S

2017-10-01

The aim of this study was to explore perspectives of transition and transition readiness of young adult patients (YAs) with sickle cell disease (SCD) who have transitioned to adult health care. In all, 19 YAs with SCD (ages 18-30 years) participated in one of three focus groups and completed a brief questionnaire about transition topics. Transcripts were coded and emergent themes were examined using the social-ecological model of adolescent and young adult readiness for transition (SMART). Themes were consistent with most SMART components. Adult provider relationships and negative medical experiences emerged as salient factors. YAs ranked choosing an adult provider, seeking emergency care, understanding medications/medication adherence, knowing SCD complications, and being aware of the impact of health behaviors as the most important topics to include in transition programming. The unique perspectives of YAs can inform the development and evaluation of SCD transition programming by incorporating the identified themes. © The Author 2017. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

What support do health visitor mentors need?

PubMed

Morton, Sarah

2013-08-01

This paper seeks to explore and understand the role of health visitor mentors undertaking a mentoring responsibility for specialist community public health nurses. During the unprecedented round of health visitor training, responsibility for the direct management of this role has been devolved from practice teachers to mentors. A qualitative approach using a purposive sample of eight participants and a semi-structured interview was the chosen method. Simple qualitative analysis was undertaken allowing data to be compared and themes identified. The overarching theme within this study was 'powerlessness'; mentors felt they had no say in adopting this role which was imposed upon them. Sub-themes included 'preparedness' relating to their perceived lack of appropriate training, and 'emotional support', which identified inadequate support from managers, while good levels of support were experienced by most mentors from their colleagues. Finally, 'compromising' related to difficulties associated with managing client care, student education and family responsibilities, achieved through prioritising and working overtime. In conclusion, the paper suggests that mentors need further support that acknowledges the pressure of the dual role, and standards for professional development of mentors need to be developed.

'I stayed with my illness': a grounded theory study of health seeking behaviour and treatment pathways of patients with obstetric fistula in Kenya.

PubMed

Khisa, Anne M; Omoni, Grace M; Nyamongo, Isaac K; Spitzer, Rachel F

2017-09-29

Obstetric fistula classic symptoms of faecal and urinary incontinence cause women to live with social stigma, isolation, psychological trauma and lose their source of livelihoods. There is a paucity of studies on the health seeking behaviour trajectories of women with fistula illness although women live with the illness for decades before surgery. We set out to establish the complete picture of women's health seeking behaviour using qualitative research. We sought to answer the question: what patterns of health seeking do women with obstetric fistula display in their quest for healing? We used grounded theory methodology to analyse data from narratives of women during inpatient stay after fistula surgery in 3 hospitals in Kenya. Emergent themes contributed to generation of substantive theory and a conceptual framework on the health seeking behaviour of fistula patients. We recruited 121 participants aged 17 to 62 years whose treatment pathways are presented. Participants delayed health seeking, living with fistula illness after their first encounter with unresponsive hospitals. The health seeking trajectory is characterized by long episodes of staying home with illness for decades and consulting multiple actors. Staying with fistula illness entailed health seeking through seven key actions of staying home, trying home remedies, consulting with private health care providers, Non-Governmental organisations, prayer, traditional medicine and formal hospitals and clinics. Long treatment trajectories at hospital resulted from multiple hospital visits and surgeries. Seeking treatment at hospital is the most popular step for most women after recognizing fistula symptoms. We conclude that the formal health system is not responsive to women's needs during fistula illness. Women suffer an illness with a chronic trajectory and seek alternative forms of care that are not ideally placed to treat fistula illness. The results suggest that a robust health system be provided with expertise and facilities to treat obstetric fistula to shorten women's treatment pathways.

Changing Needs for Information and Support in an Online System for Parents of Children With Kidney Disease

PubMed Central

Pinsk, Maury; Nicholas, David

2017-01-01

Background: Pediatric chronic kidney disease is psychologically, financially, and physically demanding on parents providing care. Parents often feel isolated because of the rarity of the condition, and geographic isolation often compounds this perception in Canada. Many parents seek assistance online for both information and social support. Objective: This study examines an online portal, titled “Ability Online,” which was designed to provide support and information to a diverse group of parents using chat facilities, bulletin boards, and e-mail. Specifically, we sought to identify how the technologies offered in this system related to the support and information seeking needs for parents. Secondary aims of determining possible reasons for attrition over time were explored as well. Design: Mixed methodology sequential exploratory design using the qualitative methodology of descriptive interpretation. Setting: Telephone interviews. Patients: Twenty parents of pediatric patients with chronic kidney disease from four Canadian centers who engaged in an online social support system “Ability Online.” Measurements: Interview transcripts generated from 20 taped phone conversations were reviewed from parents who engaged in the online system, and the themes derived from these transcripts served to generate semistructured interview questions that focused on their use of, and perceived benefit from, this technology for social support. Follow-up telephone interviews were then conducted with a 6-person subset of the original group in an effort to further define the impact of technology on their experience. This same smaller cohort provided data on social supports, caregiver satisfaction, and caregiver stress. Results: Many parents experience a progression through which their needs for knowledge and support change over time. Specifically, parents describe a transition from pure information seeking, to seeking parental interaction, mutual support and collaboration, and ultimately to advocacy. Parents described how technology could be used to address those needs. Limitations: Our cohort was slightly more educated and representative of more urban populations than published data reflecting the population of North American pediatric patients living with kidney disease. Conclusions: Our data suggest themes of technology use influencing the goals of online support seeking. While our findings are preliminary, further study may inform Web designers to identify the changing needs of participants in designing such online support networks, and minimize the reasons that participants fail to adopt, or terminate their online experiences. PMID:28717515

The experiences of security industry contractors working in Iraq: an interpretative phenomenological analysis.

PubMed

Messenger, Katy; Farquharson, Lorna; Stallworthy, Pippa; Cawkill, Paul; Greenberg, Neil

2012-07-01

To explore the occupational experiences of private security contractors working in a war zone and how it impacts on their mental health. Semistructured interviews were conducted with seven contractors employed by a large UK-based private security company. Interpretative phenomenological analysis was used to analyze the interview transcripts. Participants also completed the 12-item General Health Questionnaire and the Posttraumatic Stress Disorder Checklist. Four overarching themes emerged: the appeal of the job; vulnerability; keep going; and seeking help for stress in the workplace. No clinically significant levels of distress were reported. Contractors are frequently exposed to stressors known to increase risk of psychiatric difficulty in military personnel. A number of potential protective factors were identified. Only a minority of participants were open to seeking help for mental health difficulties.

Advancing the literature on designing audit and feedback interventions: identifying theory-informed hypotheses.

PubMed

Colquhoun, Heather L; Carroll, Kelly; Eva, Kevin W; Grimshaw, Jeremy M; Ivers, Noah; Michie, Susan; Sales, Anne; Brehaut, Jamie C

2017-09-29

Audit and feedback (A&F) is a common strategy for helping health providers to implement evidence into practice. Despite being extensively studied, health care A&F interventions remain variably effective, with overall effect sizes that have not improved since 2003. Contributing to this stagnation is the fact that most health care A&F interventions have largely been designed without being informed by theoretical understanding from the behavioral and social sciences. To determine if the trend can be improved, the objective of this study was to develop a list of testable, theory-informed hypotheses about how to design more effective A&F interventions. Using purposive sampling, semi-structured 60-90-min telephone interviews were conducted with experts in theories related to A&F from a range of fields (e.g., cognitive, health and organizational psychology, medical decision-making, economics). Guided by detailed descriptions of A&F interventions from the health care literature, interviewees described how they would approach the problem of designing improved A&F interventions. Specific, theory-informed hypotheses about the conditions for effective design and delivery of A&F interventions were elicited from the interviews. The resulting hypotheses were assigned by three coders working independently into themes, and categories of themes, in an iterative process. We conducted 28 interviews and identified 313 theory-informed hypotheses, which were placed into 30 themes. The 30 themes included hypotheses related to the following five categories: A&F recipient (seven themes), content of the A&F (ten themes), process of delivery of the A&F (six themes), behavior that was the focus of the A&F (three themes), and other (four themes). We have identified a set of testable, theory-informed hypotheses from a broad range of behavioral and social science that suggest conditions for more effective A&F interventions. This work demonstrates the breadth of perspectives about A&F from non-healthcare-specific disciplines in a way that yields testable hypotheses for healthcare A&F interventions. These results will serve as the foundation for further work seeking to set research priorities among the A&F research community.

What Is Career Success for Academic Hospitalists? A Qualitative Analysis of Early-Career Faculty Perspectives.

PubMed

Cumbler, Ethan; Yirdaw, Essey; Kneeland, Patrick; Pierce, Read; Rendon, Patrick; Herzke, Carrie; Jones, Christine D

2018-06-01

Understanding the concept of career success is critical for hospital medicine groups seeking to create sustainably rewarding faculty positions. Conceptual models of career success describe both extrinsic (compensation and advancement) and intrinsic (career satisfaction and job satisfaction) domains. How hospitalists define career success for themselves is not well understood. In this study, we qualitatively explore perspectives on how early-career clinician-educators define career success. We developed a semistructured interview tool of open-ended questions validated by using cognitive interviewing. Transcribed interviews were conducted with 17 early-career academic hospitalists from 3 medical centers to thematic saturation. A mixed deductiveinductive, qualitative, analytic approach was used to code and map themes to the theoretical framework. The single most dominant theme participants described was "excitement about daily work," which mapped to the job satisfaction organizing theme. Participants frequently expressed the importance of "being respected and recognized" and "dissemination of work," which were within the career satisfaction organizing theme. The extrinsic organizing themes of advancement and compensation were described as less important contributors to an individual's sense of career success. Ambivalence toward the "academic value of clinical work," "scholarship," and especially "promotion" represented unexpected themes. The future of academic hospital medicine is predicated upon faculty finding career success. Clinician-educator hospitalists view some traditional markers of career advancement as relevant to success. However, early-career faculty question the importance of some traditional external markers to their personal definitions of success. This work suggests that the selfconcept of career success is complex and may not be captured by traditional academic metrics and milestones. © 2018 Society of Hospital Medicine

A Thematic Analysis of Online Discussion Boards for Brachial Plexus Injury.

PubMed

Morris, Marie T; Daluiski, Aaron; Dy, Christopher J

2016-08-01

Patients with brachial plexus injury (BPI) and their family members contribute to Internet discussion groups dedicated to BPI. We hypothesized that a thematic analysis of posts from BPI Internet discussion groups would reveal common themes related to the BPI patient experience, providing topics for patient education and counseling. Internet discussion boards were identified using the search term "brachial plexus injury support group" in Google, Bing, and Yahoo! search engines. Two discussion boards had substantially more posts than other Web sites and were chosen for analyses. Posts from January 1, 2015, through January 1, 2016, were examined. Using an iterative and established process, 2 investigators (M.T.M. and C.J.D) independently analyzed each post using thematic analysis in 3 steps (open coding, axial coding, and selective coding) to determine common themes. In this process, each post was reviewed 3 times. A total of 328 posts from the 2 leading discussion boards were analyzed. Investigators reached a consensus on themes for all posts. One central theme focused on emotional aspects of BPI. Four other central themes regarding information support were identified: BPI disease, BPI treatment, recovery after BPI treatment, and process of seeking care for BPI. Examination of posts on Internet support groups for BPI revealed recurring concerns, questions, and opinions of patients and their family members. The most common themes related to disease information, treatment, recovery, and the emotional element of BPI. These findings provide a helpful starting point in refining topics for patient education and support that are targeted on patients' interests and concerns. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Seeking, accepting and declining help for emotional distress in cancer: A systematic review and thematic synthesis of qualitative evidence.

PubMed

Carolan, C M; Smith, A; Davies, G R; Forbat, L

2018-03-01

Many individuals affected by cancer who experience emotional distress report not wanting help. This review aims to understand why individuals affected by cancer seek, accept or decline help for emotional distress and what influences these actions. A systematic review and thematic synthesis of the qualitative literature was conducted. Using pre-defined search terms, four electronic databases were searched from January 2000 to May 2016. Pre-determined inclusion and exclusion criteria were then applied. Identified papers were quality appraised. In total, 32 papers were included in the synthesis. Four themes emerged from data synthesis: attaining normality-the normality paradox; being emotionally literate; perceptions of help; needs-support gap. Attaining normality is ideographic, context dependent and temporally situated; some individuals maintain normality by not seeking/declining help whereas others seek/accept help to achieve a new normality. Thus, attaining normality paradoxically functions to explain both why individuals sought/accepted help or did not seek/declined help. Data indicate that a context dependent, systems thinking approach is merited to enhance psychosocial care. In particular, clinicians must actively explore the personal context of an individual's distress to ensure that help desired and help offered are mutually understood. Further research must address the limitations of the current evidence base to advance theoretical understanding. © 2017 John Wiley & Sons Ltd.

Meaningful lives: elders in treatment for depression.

PubMed

Ragan, Meredith; Kane, Catherine F

2010-12-01

Depression among elderly persons is common. Major depression is disabling, highly prevalent, and adversely affects daily function and quality of life. Although studies have demonstrated that interpersonal psychotherapy (IPT) and medication can relieve the symptoms of depression, many elders do not seek treatment. Of those elders who do participate in treatment experience, 20% to 50% do not experience partial or full relief from depressive symptoms. Improvements in treatment strategies are needed to better serve this population. In this study, 20 elders in treatment for depression with IPT and medication were interviewed to better understand their day-to-day lives. These interviews provided insights and perspectives to inform clinical practice and improve treatment strategies. The major themes identified were independence, spirituality, family, depression, medical comorbidities, and motivation. Potential treatment strategies were derived from these themes. Copyright © 2010 Elsevier Inc. All rights reserved.

The clinical nurse educator as leader.

PubMed

Adelman-Mullally, Theresa; Mulder, Cindy K; McCarter-Spalding, Deborah E; Hagler, Debra A; Gaberson, Kathleen B; Hanner, Mary Beth; Oermann, Marilyn H; Speakman, Elizabeth T; Yoder-Wise, Patricia S; Young, Patricia K

2013-01-01

The National League for Nursing recognizes leadership as an important aspect of the educator role. The purpose of this article is to describe leadership in the context of clinical nursing education and how clinical nurse educators enact leadership. The article identifies particular nursing practice skills and strengths that clinicians bring to nursing education that enhance leadership knowledge, skills, and abilities. After review of several leadership models, we identified five overarching themes that demonstrate how clinical nurse educators exemplify the various models including role modeling, providing vision, helping students to learn, challenging the system or status quo, and seeking relational integrity. We explicate the themes with examples affirming the leadership potential of clinical nurse educators, and suggest ways in which nursing faculty members and administrators might draw on the leadership capital of clinical nurse educators. Copyright © 2012 Elsevier Ltd. All rights reserved.

Galactic Teamwork Makes Distant Bubbles

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-03-01

During the period of reionization that followed the dark ages of our universe, hydrogen was transformed from a neutral state, which is opaque to radiation, to an ionized one, which is transparent to radiation. But what generated the initial ionizing radiation? The recent discovery of multiple distant galaxies offers evidence for how this process occurred.Two Distant GalaxiesWe believe reionization occurred somewhere between a redshift of z = 6 and 7, because Ly-emitting galaxies drop out at roughly this redshift. Beyond this distance, were generally unable to see the light from these galaxies, because the universe is no longer transparent to their emission. This is not always the case, however: if a bubble of ionized gas exists around a distant galaxy, the radiation can escape, allowing us to see the galaxy.This is true of two recently-discovered Ly-emitting galaxies, confirmed to be at a redshift of z~7 and located near one another in a region known as the Bremer Deep Field. The fact that were able to see the radiation from these galaxies means that they are in an ionized HII region presumably one of the earlier regions to have become reionized in the universe.But on their own, neither of these galaxies is capable of generating an ionized bubble large enough for their light to escape. So what ionized the region around them, and what does this mean for our understanding of how reionization occurred in the universe?A Little Help From FriendsLocation in different filters of the objects in the Hubble Bremer Deep Field catalog. The z~7 selection region is outlined by the grey box. BDF-521 and BDF-3299 were the two originally discovered galaxies; the remaining red markers indicate the additional six galaxies discovered in the same region. [Castellano et al. 2016]A team of scientists led by Marco Castellano (Rome Observatory, INAF) investigated the possibility that there are other, faint galaxies near these two that have helped to ionize the region. Performing a survey using deep field Hubble observations, Castellano and collaborators found an additional 6 galaxies in the same region as the first two, also at a redshift of z~7!The authors believe these galaxies provide a simple explanation of the ionized bubble: each of these faint, normal galaxies produced a small ionized bubble. The overlap of these many small bubbles provided the larger ionized region from which the light of the two originally discovered galaxies was able to escape.How normal is this clustering of galaxies found by Castellano and collaborators? The team demonstrates via cosmological modeling that the number density of galaxies in this region is a factor of 34 greater than would be expected at this distance in a random pointing of the same size.These results greatly support the theoretical prediction that the first ionization fronts in the universe were formed in regions with significant galaxy overdensities. The discovery of this deep-field collection of galaxies strongly suggests that reionization was driven by faint, normal star-forming galaxies in a clumpy process.CitationM. Castellano et al 2016 ApJ 818 L3. doi:10.3847/2041-8205/818/1/L3

From Cosmic Dusk till Dawn with RELICS

NASA Astrophysics Data System (ADS)

Bradac, Marusa

When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and the epoch of reionization? What are the conditions in typical lowmass, star-forming galaxies at z 4? Why is galaxy evolution dependent on environment? Recent observations indicate several critical puzzles in studies that address these questions. Chief among these, galaxies might have started forming stars earlier than previously thought (<400Myr after the Big Bang) and their star formation history differs from what is predicted from simulations. Furthermore, the details of the mechanisms that regulate star formation and morphological transformation in dense environments are still unknown. To solve these puzzles of galaxy evolution, we will use 41 galaxy clusters from the RELICS program (Reionization Lensing Cluster Survey) that are among the most powerful cosmic telescopes. Their magnification will allow us to study stellar properties of a large number of galaxies all the way to the reionization era. Accurate knowledge of stellar masses, ages, and star formation rates (SFRs) requires measuring both rest-frame UV and optical light, which only Spitzer can probe at z>0.5-11 for a sufficiently large sample of typical galaxies. This program will combine Spitzer imaging from two large programs, Director Discretionary Time (DDT) and the SRELICS program led by the PI.The main challenge in a study such as this is the capability to perform reliable photometry in crowded fields. Our team recently helped develop TPHOT, which is a much improved and much faster version of previously available codes. TPHOT is specifically designed to extract fluxes in crowded fields with very different PSFs. We will combine Spitzer photometry with ground based imaging and spectroscopy to obtain robust measurements of galaxy star formation rates, stellar masses, and stellar ages. This program will be a crucial legacy complement to previous Spitzer/IRAC deep blank field surveys and cluster studies, and will open up new parameter space by probing intrinsically fainter objects than most current surveys with a significantly improved sample variance over deep field surveys. It will allow us to study the properties (e.g. SFRs and stellar masses) of a large number of galaxies (200 at z=6-10), thus meeting our goal of reconstructing the cosmic SFR density with sufficient precision to better understand the role of galaxies in the reionization process. We will measure the presence (or absence) of established stellar populations with Spitzer for the largest sample to date. Furthermore this proposal will allow us to study the SFRs of the intrinsically faint (and magnified) intermediate redshift (z 4) galaxies, as well as the stellar mass function of z=0.3-0.7 galaxy members of our cluster sample, thereby expanding our understanding of star formation from reionization to the epoch of galaxy formation and dense environments. Many of the science goals of this proposal are main science drivers for JWST. Due to magnification our effective depth and resolution match those of the JWST blank fields and affords us a sneak preview of JWST sources with Spitzer now. This program will thus provide a valuable test-bed for simulations, observation planning and source selection just in time for JWST Cycle 1.

A model of adaptation of overseas nurses: exploring the experiences of Japanese nurses working in Australia.

PubMed

Kishi, Yuka; Inoue, Kumiyo; Crookes, Patrick; Shorten, Allison

2014-04-01

The purpose of the study was to investigate the experiences of Japanese nurses and their adaptation to their work environment in Australia. Using a qualitative research method and semistructured interviews, the study aimed to discover, describe, and analyze the experiences of 14 Japanese nurses participating in the study. A qualitative study. Fourteen Japanese registered nurses working in Australian hospitals participated in the study. Individual semistructured interviews were conducted from April to June in 2008. Thematic analysis was used to identify themes within the data. Analysis of qualitative open-ended questions revealed the participants' adaptation process. It consists of three themes or phases: seeking (S), acclimatizing (A), and settling (S), subsequently named the S.A.S. model. The conceptual model of the adaptation processes of 14 Japanese nurses working in Australia includes the seeking, acclimatizing, and settling phases. Although these phases are not mutually exclusive and the process is not necessarily uniformly linear, all participants in this study passed through this S.A.S. model in order to adapt to their new environment. The S.A.S. model of adaptation helps to describe the experiences of Japanese overseas qualified nurses working in Australian hospitals. Future research is needed to examine whether this model can be applied to nurses from other countries and in other settings outside Australia.

Internet discussion forums, an information and support resource for orthognathic patients.

PubMed

Bhamrah, Gurprit; Ahmad, Sofia; NiMhurchadha, Sinead

2015-01-01

Orthognathic patients appear to be increasingly using the Internet to obtain information about their proposed treatment. The aim of this study was to investigate the information that orthognathic patients share and discuss with peers away from the clinical environment to improve the provision of information for orthognathic patients. Posts made by persons in a large publicly accessible online orthognathic discussion forum were analyzed; 1912 randomly selected forum posts were evaluated using a qualitative analysis technique known as "thematic analysis" that involves coding the posts and collating them into meaningful and distinct themes. The main themes identified were (1) reasons for undergoing orthognathic treatment, (2) presurgery and postsurgery treatment stages including orthodontics, (3) surgery including postsurgical complications and difficulties, (4) expected and actual end of treatment changes, and (5) seeking and sharing information. This study demonstrates that orthognathic patients look to the Internet to supplement information regarding their proposed treatment. This may suggest a possible gap in the provision of information by health care professionals. However, it is clear that patients use Internet forums to seek additional information, support, and reassurance from peers undergoing similar treatment. Therefore, there is a need for clinicians to ensure that patients have access and are guided to appropriate and relevant Internet resources. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Perceptions of Mindfulness in a Low-income, Primarily African American Treatment-Seeking Sample.

PubMed

Spears, Claire Adams; Houchins, Sean C; Bamatter, Wendy P; Barrueco, Sandra; Hoover, Diana Stewart; Perskaudas, Rokas

2017-12-01

Individuals with low socioeconomic status (SES) and members of racial/ethnic minority groups often experience profound disparities in mental health and physical well-being. Mindfulness-based interventions show promise for improving mood and health behaviors in higher-SES and non-Latino White populations. However, research is needed to explore what types of adaptations, if any, are needed to best support underserved populations. This study used qualitative methods to gain information about a) perceptions of mindfulness, b) experiences with meditation, c) barriers to practicing mindfulness, and d) recommendations for tailoring mindfulness-based interventions in a low-income, primarily African American treatment-seeking sample. Eight focus groups were conducted with 32 adults (16 men and 16 women) currently receiving services at a community mental health center. Most participants (91%) were African American. Focus group data were transcribed and analyzed using NVivo 10. A team of coders reviewed the transcripts to identify salient themes. Relevant themes included beliefs that mindfulness practice might improve mental health (e.g., managing stress and anger more effectively) and physical health (e.g., improving sleep and chronic pain, promoting healthier behaviors). Participants also discussed ways in which mindfulness might be consistent with, and even enhance, their religious and spiritual practices. Results could be helpful in tailoring mindfulness-based treatments to optimize feasibility and effectiveness for low-SES adults receiving mental health services.

The Lived Experience of Iranian Women Confronting Breast Cancer Diagnosis.

PubMed

Mehrabi, Esmat; Hajian, Sepideh; Simbar, Masoomeh; Hoshyari, Mohammad; Zayeri, Farid

2016-03-01

The populations who survive from breast cancer are growing; nevertheless, they mostly encounter with many cancer related problems in their life, especially after early diagnosis and have to deal with these problems. Except for the disease entity, several socio-cultural factors may affect confronting this challenge among patients and the way they deal with. Present study was carried out to prepare clear understanding of Iranian women's lived experiences confronting breast cancer diagnosis and coping ways they applied to deal with it. This study was carried out by using qualitative phenomenological design. Data gathering was done through purposive sampling using semi-structured, in-depth interviews with 18 women who survived from breast cancer. The transcribed interviews were analyzed using Van Manen's thematic analysis approach. Two main themes were emerged from the interviews including "emotional turbulence" and "threat control". The first, comprised three sub themes including uncertainty, perceived worries, and living with fears. The second included risk control, recurrence control, immediate seeking help, seeking support and resource to spirituality. Emotional response was the immediate reflection to cancer diagnosis. However, during post-treatment period a variety of emotions were not uncommon findings, patients' perceptions have been changing along the time and problem-focused coping strategies have replaced. Although women may experience a degree of improvement and adjustment with illness, the emotional problems are not necessarily resolved, they may continue and gradually engender positive outcomes.

A High-Resolution Study of the IGM at 5 < z < 6.4

NASA Astrophysics Data System (ADS)

Becker, G. D.; Sargent, W. L. W.; Rauch, M.; Simcoe, R. A.

2005-12-01

The complete Lyman-alpha absorption seen in the spectra of z > 6 quasars suggest that the reionization of the IGM may have completed as late as z = 6.2. However, this late reionization scenario remains controversial due in part to studies of galaxy luminosity functions, which favor a highly-ionized IGM out to z > 6.5. In order to improve our understanding of the IGM at these redshifts, we have acquired Keck/HIRES spectra of nine quasars at 4.8 < z < 6.4. These are the first high-resolution spectra ever taken at z > 4.6, and are providing the first detailed look at the very high-redshift IGM. We will present the first results from this data set, highlighting the evolution of the Lyman-alpha forest and the quasar proximity regions. The high-resolution data also reveal an overabundance of O I systems at z > 6 towards SDSS J1148+5251. These O I absorbers may represent the last pockets of neutral gas to be reionized at z ˜ 6. Alternatively, they may be caused by enriched galaxy halos physically similar to those observed at lower redshift. For these systems we are able to measure accurate column densities of O I, C II, and Si II. The relative abundances are consistent with the yields of ordinary Type II supernovae, with at most ˜ 30% of the silicon contributed by very massive stars. GDB and WLWS have been supported by the NSF through grants AST 99-00733 and AST 02-06067. MR has been supported by the NSF under grant AST 00-98492. RAS has been supported by the MIT Pappalardo Fellowship program.

Simulations for 21 cm radiation lensing at EoR redshifts

NASA Astrophysics Data System (ADS)

Romeo, Alessandro; Metcalf, Robert Benton; Pourtsidou, Alkistis

2018-02-01

We introduce simulations aimed at assessing how well weak gravitational lensing of 21cm radiation from the Epoch of Reionization (z ˜ 8) can be measured by a Square Kilometre Array (SKA)-like radio telescope. A simulation pipeline has been implemented to study the performance of lensing reconstruction techniques. We show how well the lensing signal can be reconstructed using the 3D quadratic lensing estimator in Fourier space assuming different survey strategies. The numerical code introduced in this work is capable of dealing with issues that cannot be treated analytically such as the discreteness of visibility measurements and the inclusion of a realistic model for the antennas distribution. This paves the way for future numerical studies implementing more realistic re-ionization models, foreground subtraction schemes, and testing the performance of lensing estimators that take into account the non-Gaussian distribution of HI after re-ionization. If multiple frequency channels covering z ˜ 7-11.6 are combined, Phase 1 of SKA-Low should be able to obtain good quality images of the lensing potential with a total resolution of ˜1.6 arcmin. The SKA-Low Phase 2 should be capable of providing images with high fidelity even using data from z ˜ 7.7 to 8.3. We perform tests aimed at evaluating the numerical implementation of the mapping reconstruction. We also discuss the possibility of measuring an accurate lensing power spectrum. Combining data from z ˜ 7 to 11.6 using the SKA2-Low telescope model, we find constraints comparable to sample variance in the range L < 1000, even for survey areas as small as 25 deg2.

Extreme Wolf-Rayet Galaxies with HST/COS: Understanding CIII] Emission in the Reionization Era

NASA Astrophysics Data System (ADS)

Stark, Daniel

2017-08-01

The first deep spectra of reionization-era galaxies have revealed strong UV nebular emission in high-ionization lines. This is in striking contrast to massive galaxies at lower redshifts, where emission from CIII], OIII], HeII, and CIV is rarely seen. These lines will likely be the only probe available for the most distant galaxies JWST will detect; but we are still unprepared to interpret them. Modeling predicts that intense UV nebular emission can only be produced below a tenth solar metallicity. However, recent HST/COS observations of local galaxies suggest that extreme populations of Wolf-Rayet (WR) stars, the hot exposed cores of massive O stars, may be capable of powering CIII] at metallicities as high as a half-solar. If these moderately metal-poor extreme WR galaxies are indeed a viable source of strong CIII] emission, our interpretation of CIII] detections in the reionization era will be dramatically altered; but we presently have sufficient UV coverage for only three examples. Here, we propose HST/COS G160M and G185M observations of an additional seven extreme WR galaxies spanning 0.5 dex in metallicity around half-solar. These observations will constrain the maximum CIII] equivalent width these galaxies can power as a function of metallicity. The moderate resolution gratings will robustly characterize the massive O and WR star populations, allowing us to link the nebular emission directly to the massive stars responsible. These data will provide a stringent test for the population synthesis codes which will be applied to JWST observations. Without this empirical baseline, our understanding of the most distant galaxies JWST finds will be severely limited.

Connecting the First Galaxies with Ultrafaint Dwarfs in the Local Group: Chemical Signatures of Population III Stars

NASA Astrophysics Data System (ADS)

Jeon, Myoungwon; Besla, Gurtina; Bromm, Volker

2017-10-01

We investigate the star formation history (SFH) and chemical evolution of isolated analogs of Local Group (LG) ultrafaint dwarf galaxies (UFDs; stellar mass range of {10}2 {M}⊙ < {M}* < {10}5 {M}⊙ ) and gas-rich, low-mass dwarfs (Leo P analogs; stellar mass range of {10}5 {M}⊙ < {M}* < {10}6 {M}⊙ ). We perform a suite of cosmological hydrodynamic zoom-in simulations to follow their evolution from the era of the first generation of stars down to z = 0. We confirm that reionization, combined with supernova (SN) feedback, is primarily responsible for the truncated star formation in UFDs. Specifically, halos with a virial mass of {M}{vir}≲ 2× {10}9 {M}⊙ form ≳ 90 % of stars prior to reionization. Our work further demonstrates the importance of Population III stars, with their intrinsically high [{{C}}/{Fe}] yields and the associated external metal enrichment, in producing low-metallicity stars ([{Fe}/{{H}}]≲ -4) and carbon-enhanced metal-poor (CEMP) stars. We find that UFDs are composite systems, assembled from multiple progenitor halos, some of which hosted only Population II stars formed in environments externally enriched by SNe in neighboring halos, naturally producing extremely low metallicity Population II stars. We illustrate how the simulated chemical enrichment may be used to constrain the SFHs of true observed UFDs. We find that Leo P analogs can form in halos with {M}{vir}˜ 4× {10}9 {M}⊙ (z = 0). Such systems are less affected by reionization and continue to form stars until z = 0, causing higher-metallicity tails. Finally, we predict the existence of extremely low metallicity stars in LG UFD galaxies that preserve the pure chemical signatures of Population III nucleosynthesis.

The hydrogen epoch of reionization array dish III: measuring chromaticity of prototype element with reflectometry

NASA Astrophysics Data System (ADS)

Patra, Nipanjana; Parsons, Aaron R.; DeBoer, David R.; Thyagarajan, Nithyanandan; Ewall-Wice, Aaron; Hsyu, Gilbert; Leung, Tsz Kuk; Day, Cherie K.; de Lera Acedo, Eloy; Aguirre, James E.; Alexander, Paul; Ali, Zaki S.; Beardsley, Adam P.; Bowman, Judd D.; Bradley, Richard F.; Carilli, Chris L.; Cheng, Carina; Dillon, Joshua S.; Fadana, Gcobisa; Fagnoni, Nicolas; Fritz, Randall; Furlanetto, Steve R.; Glendenning, Brian; Greig, Bradley; Grobbelaar, Jasper; Hazelton, Bryna J.; Jacobs, Daniel C.; Julius, Austin; Kariseb, MacCalvin; Kohn, Saul A.; Lebedeva, Anna; Lekalake, Telalo; Liu, Adrian; Loots, Anita; MacMahon, David; Malan, Lourence; Malgas, Cresshim; Maree, Matthys; Martinot, Zachary; Mathison, Nathan; Matsetela, Eunice; Mesinger, Andrei; Morales, Miguel F.; Neben, Abraham R.; Pieterse, Samantha; Pober, Jonathan C.; Razavi-Ghods, Nima; Ringuette, Jon; Robnett, James; Rosie, Kathryn; Sell, Raddwine; Smith, Craig; Syce, Angelo; Tegmark, Max; Williams, Peter K. G.; Zheng, Haoxuan

2018-04-01

Spectral structures due to the instrument response is the current limiting factor for the experiments attempting to detect the redshifted 21 cm signal from the Epoch of Reionization (EoR). Recent advances in the delay spectrum methodology for measuring the redshifted 21 cm EoR power spectrum brought new attention to the impact of an antenna's frequency response on the viability of making this challenging measurement. The delay spectrum methodology provides a somewhat straightforward relationship between the time-domain response of an instrument that can be directly measured and the power spectrum modes accessible to a 21 cm EoR experiment. In this paper, we derive the explicit relationship between antenna reflection coefficient ( S 11) measurements made by a Vector Network Analyzer (VNA) and the extent of additional foreground contaminations in delay space. In the light of this mathematical framework, we examine the chromaticity of a prototype antenna element that will constitute the Hydrogen Epoch of Reionization Array (HERA) between 100 and 200 MHz. These reflectometry measurements exhibit additional structures relative to electromagnetic simulations, but we find that even without any further design improvement, such an antenna element will support measuring spatial k modes with line-of-sight components of k ∥ > 0.2 h Mpc- 1. We also find that when combined with the powerful inverse covariance weighting method used in optimal quadratic estimation of redshifted 21 cm power spectra the HERA prototype elements can successfully measure the power spectrum at spatial modes as low as k ∥ > 0.1 h Mpc- 1. This work represents a major step toward understanding the HERA antenna element and highlights a straightforward method for characterizing instrument response for future experiments designed to detect the 21 cm EoR power spectrum.

RELICS of the Cosmic Dawn

NASA Astrophysics Data System (ADS)

Bradac, Marusa; Coe, Dan; Strait, Victoria; Salmon, Brett; Hoag, Austin; Bradley, Larry; Ryan, Russell; Dawson, Will; Zitrin, Adi; Jones, Christine; Sharon, Keren; Trenti, Michele; Stark, Daniel; Oesch, Pascal; Lam, Danel; Carrasco Nunez, Daniela Patricia; Paterno-Mahler, Rachel; Frye, Brenda

2018-05-01

When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and epoch of reionization? Recent observations indicate at least two critical puzzles in these studies. (1) First galaxies might have started forming stars earlier than previously thought (<400Myr after the Big Bang). (2) It is still unclear what is their star formation history and whether these galaxies can reionize the Universe. Accurate knowledge of stellar masses, ages, and star formation rates at this epoch requires measuring both rest-frame UV and optical light, which only Spitzer and HST can probe at z 6-11 for a large enough sample of typical galaxies. To address this cosmic puzzle, we propose to complete deep Spitzer imaging of the fields behind the 10 most powerful cosmic telescopes selected using HST, Spitzer, and Planck data from the RELICS and SRELICS programs (Reionization Lensing Cluster Survey; 41 clusters, 190 HST orbits, 440 Spitzer hours). 6 clusters out of 10 are still lacking deep data. This proposal will be a valuable Legacy complement to the existing IRAC deep surveys, and it will open up a new parameter space by probing the ordinary yet magnified population with much improved sample variance. The program will allow us to study stellar properties of a large number, 60 galaxies at z 6-11. Deep Spitzer data will be crucial to unambiguously measure their stellar properties (age, SFR, M*). Finally this proposal will establish the presence (or absence) of an unusually early established stellar population, as was recently observed in MACS1149JD at z 9. If confirmed in a larger sample, this result will require a paradigm shift in our understanding of the earliest star formation.

Planck intermediate results: XLVI. Reduction of large-scale systematic effects in HFI polarization maps and estimation of the reionization optical depth

DOE PAGES

Aghanim, N.; Ashdown, M.; Aumont, J.; ...

2016-12-12

This study describes the identification, modelling, and removal of previously unexplained systematic effects in the polarization data of the Planck High Frequency Instrument (HFI) on large angular scales, including new mapmaking and calibration procedures, new and more complete end-to-end simulations, and a set of robust internal consistency checks on the resulting maps. These maps, at 100, 143, 217, and 353 GHz, are early versions of those that will be released in final form later in 2016. The improvements allow us to determine the cosmic reionization optical depth τ using, for the first time, the low-multipole EE data from HFI, reducingmore » significantly the central value and uncertainty, and hence the upper limit. Two different likelihood procedures are used to constrain τ from two estimators of the CMB E- and B-mode angular power spectra at 100 and 143 GHz, after debiasing the spectra from a small remaining systematic contamination. These all give fully consistent results. A further consistency test is performed using cross-correlations derived from the Low Frequency Instrument maps of the Planck 2015 data release and the new HFI data. For this purpose, end-to-end analyses of systematic effects from the two instruments are used to demonstrate the near independence of their dominant systematic error residuals. The tightest result comes from the HFI-based τ posterior distribution using the maximum likelihood power spectrum estimator from EE data only, giving a value 0.055 ± 0.009. Finally, in a companion paper these results are discussed in the context of the best-fit PlanckΛCDM cosmological model and recent models of reionization.« less

Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites

NASA Astrophysics Data System (ADS)

Wheeler, Coral; Oñorbe, Jose; Bullock, James S.; Boylan-Kolchin, Michael; Elbert, Oliver D.; Garrison-Kimmel, Shea; Hopkins, Philip F.; Kereš, Dušan

2015-10-01

We present Feedback in Realistic Environment (FIRE)/GIZMO hydrodynamic zoom-in simulations of isolated dark matter haloes, two each at the mass of classical dwarf galaxies (Mvir ≃ 1010 M⊙) and ultra-faint galaxies (Mvir ≃ 109 M⊙), and with two feedback implementations. The resulting central galaxies lie on an extrapolated abundance matching relation from M⋆ ≃ 106 to 104 M⊙ without a break. Every host is filled with subhaloes, many of which form stars. Each of our dwarfs with M⋆ ≃ 106 M⊙ has 1-2 well-resolved satellites with M⋆ = 3-200 × 103 M⊙. Even our isolated ultra-faint galaxies have star-forming subhaloes. If this is representative, dwarf galaxies throughout the Universe should commonly host tiny satellite galaxies of their own. We combine our results with the Exploring the Local Volume in Simulations (ELVIS) simulations to show that targeting ˜ 50 kpc regions around nearby isolated dwarfs could increase the chances of discovering ultra-faint galaxies by ˜35 per cent compared to random pointings, and specifically identify the region around the Phoenix dwarf galaxy as a good potential target. The well-resolved ultra-faint galaxies in our simulations (M⋆ ≃ 3-30 × 103 M⊙) form within Mpeak ≃ 0.5-3 × 109 M⊙ haloes. Each has a uniformly ancient stellar population ( > 10 Gyr) owing to reionization-related quenching. More massive systems, in contrast, all have late-time star formation. Our results suggest that Mhalo ≃ 5 × 109 M⊙ is a probable dividing line between haloes hosting reionization `fossils' and those hosting dwarfs that can continue to form stars in isolation after reionization.

Filling the Void: A Comprehensive Survey of the Intergalactic Medium at z 1 Using STIS/COS Archival Spectra

NASA Astrophysics Data System (ADS)

Khaire, Vikram

2017-08-01

There exists a large void in our understanding of the intergalactic medium (IGM) at z=0.5-1.5, spanning a significant cosmic time of 4 Gyr. This hole resulted from a paucity of near-UV QSO spectra, which were historically very expensive to obtain. However, with the advent of COS and the HST UV initiative, sufficient STIS/COS NUV spectra have finally become available, enabling the first statistical analyses. We propose a comprehensive study of the z 1 IGM using the Ly-alpha forest of 26 archival QSO spectra. This analysis will: (1) measure the distribution of HI absorbers to several percent precision down to log NHI < 13 to test our model of the IGM, and determine the extragalactic UV background (UVB) at that epoch; (2) measure the Ly-alpha forest power spectrum to 12%, providing another precision test of LCDM and our theory of the IGM; (3) measure the thermal state of the IGM, which reflects the balance of heating (photoheating, HI/HeII reionization) and cooling (Hubble expansion) of cosmic baryons, and directly verify the predicted cooldown of IGM gas after reionization for the first time; (4) generate high-quality reductions, coadds, and continuum fits that will be released to the public to enable other science cases. These results, along with our state-of-the-art hydrodynamical simulations, and theoretical models of the UVB, will fill the 4 Gyr hole in our understanding of the IGM. When combined with existing HST and ground-based data from lower and higher z, they will lead to a complete, empirical description of the IGM from HI reionization to the present, spanning more than 10 Gyr of cosmic history, adding substantially to Hubble's legacy of discovery on the IGM.

Wilkinson Microwave Anisotropy Probe (WMAP) First Year Observations: TE Polarization

NASA Technical Reports Server (NTRS)

Kogut, A.; Spergel, D. N.; Barnes, C.; Bennett, C. L.; Halpern, M.; Hinshaw, G.; Jarosik, N.; Limon, M.; Meyer, S. S.; Page, L.;

On the contribution of active galactic nuclei to the high-redshift metagalactic ionizing background

NASA Astrophysics Data System (ADS)

D'Aloisio, Anson; Upton Sanderbeck, Phoebe R.; McQuinn, Matthew; Trac, Hy; Shapiro, Paul R.

2017-07-01

Motivated by the claimed detection of a large population of faint active galactic nuclei (AGNs) at high redshift, recent studies have proposed models in which AGNs contribute significantly to the z > 4 H I ionizing background. In some models, AGNs are even the chief sources of reionization. If proved true, these models would make necessary a complete revision to the standard view that galaxies dominated the high-redshift ionizing background. It has been suggested that AGN-dominated models can better account for two recent observations that appear to be in conflict with the standard view: (1) large opacity variations in the z ˜ 5.5 H I Ly α forest, and (2) slow evolution in the mean opacity of the He II Ly α forest. Large spatial fluctuations in the ionizing background from the brightness and rarity of AGNs may account for the former, while the earlier onset of He II reionization in these models may account for the latter. Here we show that models in which AGN emissions source ≳50 per cent of the ionizing background generally provide a better fit to the observed H I Ly α forest opacity variations compared to standard galaxy-dominated models. However, we argue that these AGN-dominated models are in tension with constraints on the thermal history of the intergalactic medium (IGM). Under standard assumptions about the spectra of AGNs, we show that the earlier onset of He II reionization heats up the IGM well above recent temperature measurements. We further argue that the slower evolution of the mean opacity of the He II Ly α forest relative to simulations may reflect deficiencies in current simulations rather than favour AGN-dominated models as has been suggested.

Implications of z ~ 6 Quasar Proximity Zones for the Epoch of Reionization and Quasar Lifetimes

DOE PAGES

Eilers, Anna-Christina; Davies, Frederick B.; Hennawi, Joseph F.; ...

2017-05-02

In this paper, we study quasar proximity zones in the redshift rangemore » $$5.77\\leqslant z\\leqslant 6.54$$ by homogeneously analyzing 34 medium-resolution spectra, encompassing both archival and newly obtained data, and exploiting recently updated systemic redshift and magnitude measurements. Whereas previous studies found strong evolution of proximity zone sizes with redshift and argued that this provides evidence for a rapidly evolving intergalactic medium (IGM) neutral fraction during reionization, we measure a much shallower trend $$\\propto {(1+z)}^{-1.44}$$. We compare our measured proximity zone sizes to predictions from hydrodynamical simulations post-processed with one-dimensional radiative transfer and find good agreement between observations and theory, irrespective of the ionization state of the ambient IGM. This insensitivity to IGM ionization state has been previously noted, and results from the fact that the definition of proximity zone size as the first drop of the smoothed quasar spectrum below the 10% flux transmission level probes locations where the ionizing radiation from the quasar is an order of magnitude larger than the expected ultraviolet ionizing background that sets the neutral fraction of the IGM. Our analysis also uncovered three objects with exceptionally small proximity zones (two have $${R}_{p}\\lt 1$$ proper Mpc), which constitute outliers from the observed distribution and are challenging to explain with our radiative transfer simulations. Finally, we consider various explanations for their origin, such as strong absorption line systems associated with the quasar or patchy reionization, but find that the most compelling scenario is that these quasars have been shining for ≲10 5 years.« less

Planck intermediate results: XLVI. Reduction of large-scale systematic effects in HFI polarization maps and estimation of the reionization optical depth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aghanim, N.; Ashdown, M.; Aumont, J.

This study describes the identification, modelling, and removal of previously unexplained systematic effects in the polarization data of the Planck High Frequency Instrument (HFI) on large angular scales, including new mapmaking and calibration procedures, new and more complete end-to-end simulations, and a set of robust internal consistency checks on the resulting maps. These maps, at 100, 143, 217, and 353 GHz, are early versions of those that will be released in final form later in 2016. The improvements allow us to determine the cosmic reionization optical depth τ using, for the first time, the low-multipole EE data from HFI, reducingmore » significantly the central value and uncertainty, and hence the upper limit. Two different likelihood procedures are used to constrain τ from two estimators of the CMB E- and B-mode angular power spectra at 100 and 143 GHz, after debiasing the spectra from a small remaining systematic contamination. These all give fully consistent results. A further consistency test is performed using cross-correlations derived from the Low Frequency Instrument maps of the Planck 2015 data release and the new HFI data. For this purpose, end-to-end analyses of systematic effects from the two instruments are used to demonstrate the near independence of their dominant systematic error residuals. The tightest result comes from the HFI-based τ posterior distribution using the maximum likelihood power spectrum estimator from EE data only, giving a value 0.055 ± 0.009. Finally, in a companion paper these results are discussed in the context of the best-fit PlanckΛCDM cosmological model and recent models of reionization.« less

The Precision Array for Probing the Epoch of Re-ionization: Eight Station Results

NASA Astrophysics Data System (ADS)

Parsons, Aaron R.; Backer, Donald C.; Foster, Griffin S.; Wright, Melvyn C. H.; Bradley, Richard F.; Gugliucci, Nicole E.; Parashare, Chaitali R.; Benoit, Erin E.; Aguirre, James E.; Jacobs, Daniel C.; Carilli, Chris L.; Herne, David; Lynch, Mervyn J.; Manley, Jason R.; Werthimer, Daniel J.

2010-04-01

We are developing the Precision Array for Probing the Epoch of Re-ionization (PAPER) to detect 21 cm emission from the early universe, when the first stars and galaxies were forming. We describe the overall experiment strategy and architecture and summarize two PAPER deployments: a four-antenna array in the low radio frequency interference (RFI) environment of Western Australia and an eight-antenna array at a prototyping site at the NRAO facilities near Green Bank, WV. From these activities we report on system performance, including primary beam model verification, dependence of system gain on ambient temperature, measurements of receiver and overall system temperatures, and characterization of the RFI environment at each deployment site. We present an all-sky map synthesized between 139 MHz and 174 MHz using data from both arrays that reaches down to 80 mJy (4.9 K, for a beam size of 2.15e-5 sr at 156 MHz), with a 10 mJy (620 mK) thermal noise level that indicates what would be achievable with better foreground subtraction. We calculate angular power spectra (C ell) in a cold patch and determine them to be dominated by point sources, but with contributions from galactic synchrotron emission at lower radio frequencies and angular wavemodes. Although the sample variance of foregrounds dominates errors in these power spectra, we measure a thermal noise level of 310 mK at ell = 100 for a 1.46 MHz band centered at 164.5 MHz. This sensitivity level is approximately 3 orders of magnitude in temperature above the level of the fluctuations in 21 cm emission associated with re-ionization.

Planck intermediate results. XLVI. Reduction of large-scale systematic effects in HFI polarization maps and estimation of the reionization optical depth

NASA Astrophysics Data System (ADS)

Planck Collaboration; Aghanim, N.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Battye, R.; Benabed, K.; 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.; Carron, J.; Challinor, A.; Chiang, H. C.; Colombo, L. P. L.; Combet, C.; Comis, B.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Di Valentino, E.; Dickinson, C.; Diego, J. M.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fantaye, Y.; Finelli, F.; Forastieri, F.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Gerbino, M.; Ghosh, T.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Helou, G.; Henrot-Versillé, S.; Herranz, D.; Hivon, E.; Huang, Z.; Ilić, S.; Jaffe, A. H.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Knox, L.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Langer, M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Le Jeune, M.; Leahy, J. P.; Levrier, F.; Liguori, M.; Lilje, P. B.; López-Caniego, M.; Ma, Y.-Z.; Macías-Pérez, J. F.; Maggio, G.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Matarrese, S.; Mauri, N.; McEwen, J. D.; Meinhold, P. R.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Mottet, S.; Naselsky, P.; Natoli, P.; Oxborrow, C. A.; Pagano, L.; Paoletti, D.; Partridge, B.; Patanchon, G.; Patrizii, L.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Plaszczynski, S.; Polastri, L.; Polenta, G.; Puget, J.-L.; Rachen, J. P.; Racine, B.; Reinecke, M.; Remazeilles, M.; Renzi, A.; Rocha, G.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Ruiz-Granados, B.; Salvati, L.; Sandri, M.; Savelainen, M.; Scott, D.; Sirri, G.; Sunyaev, R.; Suur-Uski, A.-S.; Tauber, J. A.; Tenti, M.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Valiviita, J.; Van Tent, F.; Vibert, L.; Vielva, P.; Villa, F.; Vittorio, N.; Wandelt, B. D.; Watson, R.; Wehus, I. K.; White, M.; Zacchei, A.; Zonca, A.

2016-12-01

This paper describes the identification, modelling, and removal of previously unexplained systematic effects in the polarization data of the Planck High Frequency Instrument (HFI) on large angular scales, including new mapmaking and calibration procedures, new and more complete end-to-end simulations, and a set of robust internal consistency checks on the resulting maps. These maps, at 100, 143, 217, and 353 GHz, are early versions of those that will be released in final form later in 2016. The improvements allow us to determine the cosmic reionization optical depth τ using, for the first time, the low-multipole EE data from HFI, reducing significantly the central value and uncertainty, and hence the upper limit. Two different likelihood procedures are used to constrain τ from two estimators of the CMB E- and B-mode angular power spectra at 100 and 143 GHz, after debiasing the spectra from a small remaining systematic contamination. These all give fully consistent results. A further consistency test is performed using cross-correlations derived from the Low Frequency Instrument maps of the Planck 2015 data release and the new HFI data. For this purpose, end-to-end analyses of systematic effects from the two instruments are used to demonstrate the near independence of their dominant systematic error residuals. The tightest result comes from the HFI-based τ posterior distribution using the maximum likelihood power spectrum estimator from EE data only, giving a value 0.055 ± 0.009. In a companion paper these results are discussed in the context of the best-fit PlanckΛCDM cosmological model and recent models of reionization.

Results from EDGES High-band. I. Constraints on Phenomenological Models for the Global 21 cm Signal

NASA Astrophysics Data System (ADS)

Monsalve, Raul A.; Rogers, Alan E. E.; Bowman, Judd D.; Mozdzen, Thomas J.

2017-09-01

We report constraints on the global 21 cm signal due to neutral hydrogen at redshifts 14.8≥slant z≥slant 6.5. We derive our constraints from low-foreground observations of the average sky brightness spectrum conducted with the EDGES High-band instrument between 2015 September 7 and October 26. Observations were calibrated by accounting for the effects of antenna beam chromaticity, antenna and ground losses, signal reflections, and receiver parameters. We evaluate the consistency between the spectrum and phenomenological models for the global 21 cm signal. For tanh-based representations of the ionization history during the epoch of reionization, we rule out, at ≥slant 2σ significance, models with duration of up to {{Δ }}z=1 at z≈ 8.5 and higher than {{Δ }}z=0.4 across most of the observed redshift range under the usual assumption that the 21 cm spin temperature is much larger than the temperature of the cosmic microwave background during reionization. We also investigate a “cold” intergalactic medium (IGM) scenario that assumes perfect Lyα coupling of the 21 cm spin temperature to the temperature of the IGM, but that the latter is not heated by early stars or stellar remants. Under this assumption, we reject tanh-based reionization models of duration {{Δ }}z≲ 2 over most of the observed redshift range. Finally, we explore and reject a broad range of Gaussian models for the 21 cm absorption feature expected in the First Light era. As an example, we reject 100 mK Gaussians with duration (full width at half maximum) {{Δ }}z≤slant 4 over the range 14.2≥slant z≥slant 6.5 at ≥slant 2σ significance.

IDENTIFYING IONIZED REGIONS IN NOISY REDSHIFTED 21 cm DATA SETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malloy, Matthew; Lidz, Adam, E-mail: mattma@sas.upenn.edu

One of the most promising approaches for studying reionization is to use the redshifted 21 cm line. Early generations of redshifted 21 cm surveys will not, however, have the sensitivity to make detailed maps of the reionization process, and will instead focus on statistical measurements. Here, we show that it may nonetheless be possible to directly identify ionized regions in upcoming data sets by applying suitable filters to the noisy data. The locations of prominent minima in the filtered data correspond well with the positions of ionized regions. In particular, we corrupt semi-numeric simulations of the redshifted 21 cm signalmore » during reionization with thermal noise at the level expected for a 500 antenna tile version of the Murchison Widefield Array (MWA), and mimic the degrading effects of foreground cleaning. Using a matched filter technique, we find that the MWA should be able to directly identify ionized regions despite the large thermal noise. In a plausible fiducial model in which {approx}20% of the volume of the universe is neutral at z {approx} 7, we find that a 500-tile MWA may directly identify as many as {approx}150 ionized regions in a 6 MHz portion of its survey volume and roughly determine the size of each of these regions. This may, in turn, allow interesting multi-wavelength follow-up observations, comparing galaxy properties inside and outside of ionized regions. We discuss how the optimal configuration of radio antenna tiles for detecting ionized regions with a matched filter technique differs from the optimal design for measuring power spectra. These considerations have potentially important implications for the design of future redshifted 21 cm surveys.« less

National Aeronautics and Space Administration Biological and Physical Research Enterprise Strategy

NASA Technical Reports Server (NTRS)

2003-01-01

As the 21st century begins, NASA's new Vision and Mission focuses the Agency's Enterprises toward exploration and discovery.The Biological and Physical Research Enterprise has a unique and enabling role in support of the Agency's Vision and Mission. Our strategic research seeks innovations and solutions to enable the extension of life into deep space safely and productively. Our fundamental research, as well as our research partnerships with industry and other agencies, allow new knowledge and tech- nologies to bring improvements to life on Earth. Our interdisciplinary research in the unique laboratory of microgravity addresses opportunities and challenges on our home planet as well as in space environments. The Enterprise maintains a key role in encouraging and engaging the next generation of explorers from primary school through the grad- uate level via our direct student participation in space research.The Biological and Physical Research Enterprise encompasses three themes. The biological sciences research theme investigates ways to support a safe human presence in space. This theme addresses the definition and control of physiological and psychological risks from the space environment, including radiation,reduced gravity, and isolation. The biological sciences research theme is also responsible for the develop- ment of human support systems technology as well as fundamental biological research spanning topics from genomics to ecologies. The physical sciences research theme supports research that takes advantage of the space environment to expand our understanding of the fundamental laws of nature. This theme also supports applied physical sciences research to improve safety and performance of humans in space. The research partnerships and flight support theme establishes policies and allocates space resources to encourage and develop entrepreneurial partners access to space research.Working together across research disciplines, the Biological and Physical Research Enterprise is performing vital research and technology development to extend the reach of human space flight.

Barriers and facilitators of help-seeking among unemployed persons with mental health problems: a qualitative study.

PubMed

Staiger, Tobias; Waldmann, Tamara; Rüsch, Nicolas; Krumm, Silvia

2017-01-17

Unemployed people with mental health problems often do not use mental health services and therefore do not benefit from available therapies. As unemployed individuals outside the healthcare system are a hard-to-reach group, barriers to and facilitators of mental health service use are poorly understood. The purpose of this study was to identify barriers to and facilitators of help-seeking and service use based on experiences of unemployed people with mental health problems. Fifteen qualitative semi-structured individual interviews were conducted with unemployed persons who reported mental health problems. Interview topics included individual experience with help-seeking and mental health service use with a focus on barriers and facilitators. Transcripts were analysed using qualitative content analysis and major themes were identified. Participants reported being treated as "different" within their social environment as well as by health care professionals because of their mental health problems, which resulted in a lack of self-esteem and avoidance of help-seeking. Interviewees associated negative attributes with help-seeking such as helplessness and weakness. They equated psychiatric medication with illegal drugs and worried about the risk of addiction. However, social support and a desire for change on the other hand increased the motivation to search for help. Employment agency staff were mostly perceived as supportive by individuals seeking mental health services. Unemployed individuals with mental health problems faced barriers and facilitators when seeking help on three different levels: (1) mental health literacy; (2) stigma and discrimination; and (3) structures and conditions of health care. Awareness and attitudes of health care professionals concerning mental health issues should be improved. Stigmatisation of people with mental illnesses should be reduced in health care settings. Training for employment agency staff concerning mental health problems and services is recommended.

Barriers and benefits associated with nurses information seeking related to patient education needs on clinical nursing units.

PubMed

Jones, Josette; Schilling, Katherine; Pesut, Daniel

2011-01-01

The purpose of this study was to answer the following two questions: What are clinical nurses' rationales for their approaches to finding patient educational materials on the web? What are perceived barriers and benefits associated with the use of web-based information resources for patient education in the context of nursing clinical practice?Over 179 individual data units were analyzed to understand clinical nurses' rationales for their approaches to find patient educational materials on the web. Rationales were defined as those underlying catalysts or activators leading to an information need. Analyses found that the primary reasons why clinical nurses conducted web-based information searches included direct patient requests ( 9 requests), colleague requests (6 requests), building patient materials collections (4), patients' family requests (3), routine teaching (1), personal development (1), or staff development (1). From these data, four broad themes emerged: professional reasons, personal reasons, technology reasons, and organization reasons for selecting information resources. Content analysis identified 306 individual data units representing either 'benefits' (178 units) or 'barriers' (128) to the nurses' use of web resources for on-unit patient care. Inter-rater reliability was assessed and found to be excellent (r = 0.943 to 0.961). The primary themes that emerged as barriers to the used of web-based resources included: 1) time requirements to perform a search, 2) nurses' experience and knowledge about the resources or required technology, 3) specific characteristics of individuals electronic information resources, and 4) organizational procedures and policies. Three primary themes that represented the benefits of using web-based resources were also identified: 1) past experiences and knowledge of a specific resource or the required technologies, 2) availability and accessibility on the unit, and 3) specific characteristics of individual information tool. In many cases, nurses commented on specific characteristics or features of favorite information resources. Favorite sites included a variety or reputable health care organizations that displayed context in text, audio, and/or video. In addition such sites were described as easy-to read and provided content related to patient-focused information or specific content such as toll free telephone contact numbers.Information searching is the interaction between and among information users and computer-based information systems. Information seeking is becoming an important part of the knowledge work of nurses. Information seeking and searching intersects with the field of human computer interaction (HCI), which focuses on all aspects of human, and computer interactions. Users of an information system are understood as "actors" in situations, with a set of skills and shared practices based on work experiences with others. Designing better tools and developing information searching strategies that support, extend, and transform practices, begins by asking: Who are the users? What are the tasks? What is the interplay between the technology and the organization of the task? This study contributes fundamental data and information about the rationales nurses use in information seeking tasks. In addition it provides empirical evidences regarding barriers and benefits of information seeking in the context of patient education needs in inpatient clinical settings.

'Just because she's young, it doesn't mean she has to die': exploring the contributing factors to high maternal mortality in adolescents in Eastern Freetown; a qualitative study.

PubMed

November, Lucy; Sandall, Jane

2018-02-21

In Sierra Leone, 34% of pregnancies and 40% of maternal deaths are in the adolescent population. Risks are known to be higher for younger adolescents, this being borne out by a household survey in Eastern Freetown in 2015. This current qualitative study, funded by Wellbeing of Women's international midwifery fellowship, was conducted to explore the causes of this high incidence of maternal death for younger teenagers, and to identify possible interventions to improve outcomes. This qualitative study used semi-structured interviews (n = 19) and focus groups (n = 6), with a wide range of professional and lay participants, recorded with consent. Recordings were transcribed by the first author and a Krio-speaking colleague where necessary, and Nvivo software was used to assist with theming of the data around the three main research questions. Themes from discussions on vulnerability to teenage pregnancy focused on transactional sex, especially for girls living outside of their birth family. They included sex for school fees, sex with teachers for grades, sex for food and clothes, and sex to lessen the impact of the time-consuming duties of water collection and petty trading. In addition, the criminal justice system and the availability and accessibility of contraception and abortion were included within this major theme. Within the major theme of vulnerability to death once pregnant, abandonment, delayed care seeking, and being cared for by a non-parental adult were identified. Several obstetric risks were discussed by midwives, but were explicitly related to the socio-economic factors already mentioned. A cross-cutting theme throughout the data was of gendered social norms for sexual behaviour, for both boys and girls, being reinforced by significant adults such as parents and teachers. Findings challenge the notion that adolescent girls have the necessary agency to make straightforward choices about their sexual behaviour and contraceptive use. For girls who do become pregnant, risks are believed to be related more to stigma and abandonment than to physical maturity, leading to lack of family-based support and delayed care-seeking for antenatal and delivery care. Two potential interventions identified within the research are a mentoring scheme for the most vulnerable pregnant girls and a locally managed blood donation register. A feasibility study of a pilot mentoring scheme is currently underway, run by the first author and a local partner.

Status of Foreground and Instrument Challenges for 21cm EoR experiments - Design Strategies for SKA and HERA

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan

2018-05-01

Direct detection of the Epoch of Reionization (EoR) via redshifted 21 cm line of H i will reveal the nature of the first stars and galaxies as well as revolutionize our understanding of a poorly explored evolutionary phase of the Universe. Projects such as the MWA, LOFAR, and PAPER commenced in the last decade with the promise of high significance statistical detection of the EoR, but have so far only weakly constrained models owing to unforeseen challenges from bright foreground sources and instrument systematics. It is essential for next generation instruments like the HERA and SKA to have these challenges addressed. I present an analysis of these challenges - wide-field measurements, antenna beam chromaticity, reflections in the instrument, and antenna position errors - along with performance specifications and design solutions that will be critical to designing successful next-generation instruments in enabling the first detection and also in placing meaningful constraints on reionization models.

A Century of Progress in Molecular Mass Spectrometry

NASA Astrophysics Data System (ADS)

McLafferty, Fred W.

2011-07-01

The first mass spectrum of a molecule was measured by J.J. Thomson in 1910. Mass spectrometry (MS) soon became crucial to the study of isotopes and atomic weights and to the development of atomic weapons for World War II. Its notable applications to molecules began with the quantitative analysis of light hydrocarbons during World War II. When I joined the Dow Chemical Company in 1950, MS was not favored by organic chemists. This situation improved only with an increased understanding of gaseous ion chemistry, which was obtained through the use of extensive reference data. Gas chromatography-MS was developed in 1956, and tandem MS was first used a decade later. In neutralization-reionization MS, an unusual, unstable species is prepared by ion-beam neutralization and characterized by reionization. Electrospray ionization of a protein mixture produces its corresponding ionized molecules. In top-down proteomics, ions from an individual component can be mass separated and subjected to collision-activated and electron-capture dissociation to provide extensive sequence information.

First Polarized Power Spectra from HERA-19 Commissioning Data: Comparison with Simulations

NASA Astrophysics Data System (ADS)

Igarashi, Amy; Chichura, Paul; Fox Fortino, Austin; Kohn, Saul; Aguirre, James; HERA Collaboration, CHAMP

2018-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope whose primary goal is the detection of redshifted 21-cm line radiation produced from the spin-flip transition of HI during the Epoch of Reionization (EoR). HERA is currently under construction in South Africa, and will eventually be an array of 350 14-m antennas. HERA aims for a statistical detection of the power spectrum of this emission, using the so-called delay spectrum technique (Parsons et al 2012). We examine a first season of commissioning data from the first 19 elements (HERA-19) to characterize Galactic and extragalactic foregrounds. We compare the delay spectrum for HERA-19 constructed from data to those constructed from simulations done using a detailed instrument electromagnetic model and using the unpolarized Global Sky Model (GSM2008). We compare the data and simulations to explore the effects of Stokes-I to Q and U leakage, and further examine whether statistical models of polarization match the observed polarized power spectra.

Cosmic reionization on computers. Ultraviolet continuum slopes and dust opacities in high redshift galaxies

DOE PAGES

Khakhaleva-Li, Zimu; Gnedin, Nickolay Y.

2016-03-30

In this study, we compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are notmore » fully sufficient. While the discrepancies with the exiting data are marginal, the future JWST data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.« less

Reionization during the dark ages from a cosmic axion background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evoli, Carmelo; Leo, Matteo; Mirizzi, Alessandro

2016-05-01

Recently it has been pointed out that a cosmic background of relativistic axion-like particles (ALPs) would be produced by the primordial decays of heavy fields in the post-inflation epoch, contributing to the extra-radiation content in the Universe today. Primordial magnetic fields would trigger conversions of these ALPs into sub-MeV photons during the dark ages. This photon flux would produce an early reionization of the Universe, leaving a significant imprint on the total optical depth to recombination τ. Using the current measurement of τ and the limit on the extra-radiation content Δ N {sub eff} by the Planck experiment we putmore » a strong bound on the ALP-photon conversions. Namely we obtain upper limits on the product of the photon-ALP coupling constant g {sub a} {sub γ} times the magnetic field strength B down to g {sub a} {sub γ} B ∼> 6 × 10{sup −18} GeV{sup −1} nG for ultralight ALPs.« less

Redshifts for Spitzer-detected galaxies at z 6 - old stars in the first Gyr

NASA Astrophysics Data System (ADS)

Lacy, Mark; Stanway, Elizabeth; Chiu, Kuenley; Douglas, Laura; Eyles, Laurence; Bunker, Andrew

2008-02-01

We have identified a population of star-forming galaxies at z 6 through the i-drop Lyman-break technique using HST/ACS. Using Spitzer/IRAC imaging (tracing the rest-frame optical), we discovered from SED-fitting that some of this population harbour relatively old stars (300-500Myr) with significant Balmer breaks, implying formation epochs of z 10. Our work suggests that UV photons from star formation at z 10 may play a key role in reionizing the Universe. However, these conclusions are drawn from the only field (GOODS-South) which has both deep Spitzer/IRAC imaging and many i-drop spectroscopic redshifts. Hence the global conclusions are compromised by cosmic variance. We have 72-hours on Spitzer to image 6 other sight-lines with deep ACS data; we propose to use GMOS multiobject mode to obtain spectroscopic redshifts, which are crucial to reduce the large uncertainties in fitting the stellar ages and masses, and hence inferring the preceding star formation history and the contribution to reionization.

Cosmological Parameters From Pre-Planck CMB Measurements: A 2017 Update

NASA Technical Reports Server (NTRS)

Calabrese, Erminia; Hlolzek, Renee A.; Bond, J. Richard; Devlin, Mark J.; Dunkley, Joanna; Halpern, Mark; Hincks, Adam D.; Irwin, Kent D.; Kosowsky, Arthur; Moodley, Kavilan;

Signal Processing for a Lunar Array: Minimizing Power Consumption

NASA Technical Reports Server (NTRS)

D'Addario, Larry; Simmons, Samuel

2011-01-01

Motivation for the study is: (1) Lunar Radio Array for low frequency, high redshift Dark Ages/Epoch of Reionization observations (z =6-50, f=30-200 MHz) (2) High precision cosmological measurements of 21 cm H I line fluctuations (3) Probe universe before first star formation and provide information about the Intergalactic Medium and evolution of large scale structures (5) Does the current cosmological model accurately describe the Universe before reionization? Lunar Radio Array is for (1) Radio interferometer based on the far side of the moon (1a) Necessary for precision measurements, (1b) Shielding from earth-based and solar RFI (12) No permanent ionosphere, (2) Minimum collecting area of approximately 1 square km and brightness sensitivity 10 mK (3)Several technologies must be developed before deployment The power needed to process signals from a large array of nonsteerable elements is not prohibitive, even for the Moon, and even in current technology. Two different concepts have been proposed: (1) Dark Ages Radio Interferometer (DALI) (2)( Lunar Array for Radio Cosmology (LARC)

Cosmic reionization on computers. Ultraviolet continuum slopes and dust opacities in high redshift galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khakhaleva-Li, Zimu; Gnedin, Nickolay Y.

In this study, we compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are notmore » fully sufficient. While the discrepancies with the exiting data are marginal, the future JWST data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaurov, Alexander A., E-mail: kaurov@uchicago.edu

The methods for studying the epoch of cosmic reionization vary from full radiative transfer simulations to purely analytical models. While numerical approaches are computationally expensive and are not suitable for generating many mock catalogs, analytical methods are based on assumptions and approximations. We explore the interconnection between both methods. First, we ask how the analytical framework of excursion set formalism can be used for statistical analysis of numerical simulations and visual representation of the morphology of ionization fronts. Second, we explore the methods of training the analytical model on a given numerical simulation. We present a new code which emergedmore » from this study. Its main application is to match the analytical model with a numerical simulation. Then, it allows one to generate mock reionization catalogs with volumes exceeding the original simulation quickly and computationally inexpensively, meanwhile reproducing large-scale statistical properties. These mock catalogs are particularly useful for cosmic microwave background polarization and 21 cm experiments, where large volumes are required to simulate the observed signal.« less

Lived Experiences of "Illness Uncertainty" of Iranian Cancer Patients: A Phenomenological Hermeneutic Study.

PubMed

Sajjadi, Moosa; Rassouli, Maryam; Abbaszadeh, Abbas; Brant, Jeannine; Majd, Hamid Alavi

2016-01-01

For cancer patients, uncertainty is a pervasive experience and a major psychological stressor that affects many aspects of their lives. Uncertainty is a multifaceted concept, and its understanding for patients depends on many factors, including factors associated with various sociocultural contexts. Unfortunately, little is known about the concept of uncertainty in Iranian society and culture. This study aimed to clarify the concept and explain lived experiences of illness uncertainty in Iranian cancer patients. In this hermeneutic phenomenological study, 8 cancer patients participated in semistructured in-depth interviews about their experiences of uncertainty in illness. Interviews continued until data saturation was reached. All interviews were recorded, transcribed, analyzed, and interpreted using 6 stages of the van Manen phenomenological approach. Seven main themes emerged from patients' experiences of illness uncertainty of cancer. Four themes contributed to uncertainty including "Complexity of Cancer," "Confusion About Cancer," "Contradictory Information," and "Unknown Future." Two themes facilitated coping with uncertainty including "Seeking Knowledge" and "Need for Spiritual Peace." One theme, "Knowledge Ambivalence," revealed the struggle between wanting to know and not wanting to know, especially if bad news was delivered. Uncertainty experience for cancer patients in different societies is largely similar. However, some experiences (eg, ambiguity in access to medical resources) seemed unique to Iranian patients. This study provided an outlook of cancer patients' experiences of illness uncertainty in Iran. Cancer patients' coping ability to deal with uncertainty can be improved.

Breast cancer patients' information seeking during surgical consultations: A qualitative, videotape-based analysis of patients' questions.

PubMed

Robinson, Jeffrey D; Venetis, Maria; Street, Richard L; Kearney, Thomas

2016-12-01

Despite data on breast cancer patients' information needs and their association with patient outcomes, there are currently no data on what U.S. patients actually ask surgeons during primary consultations. Working from transcripts of videotaped, treatment decision making consultations between breast cancer patients and surgeons, we identify all questions (by patients and companions) and then use grounded theory techniques to determine the most recurrent question-asking themes. Sample includes 132 recently diagnosed (M = 8.9 days), late-middle-aged (M = 61.2 years), female patients with predominantly early stage (0-1; 78%), first-time breast cancer (92.4%) consulting with one of nine surgeons in community based offices. Transcripts contained 2,781 questions (1,929 by patients, 852 by companions; Cohen's Kappa = 0.90), which generated 15 patient question asking themes that were represented (i.e., asked about) at least once in >20% of all consultations. Question asking themes are a concrete index of what patients want to know more about prior to treatment. Identified themes specify, modify, and extend prior findings based on self-report data. Findings potentially increase surgeons' levels of patient centered care by improving surgeons' abilities to satisfactorily address patients' information needs, which has the potential to improve both patient outcomes and clinical practice guidelines. J. Surg. Oncol. 2016;114:922-929. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Reasons identified for seeking the American Physical Therapy Association-Credentialed Clinical Instructor Program (CCIP) in Florida.

PubMed

Musolino, Gina M; van Duijn, Jacqueline; Noonan, Ann C; Eargle, Linda K; Gray, Debra L

2013-01-01

The American Physical Therapy Association's (APTA) Strategic Plan strives to increase the number of APTA credentialed clinical instructors. Available to all health care providers, as of 2012, there were 39,851 credentialed clinical instructors. Study purposes were threefold: to determine participants' a. reasons to attend the APTA Credentialed Clinical Instructor Program (CCIP); b. pre-CCIP learning goals; and c. related post-CCIP learning outcomes. This IRB-approved study was completed with informed consent procedures followed. APTA CCIP credentialed trainers (n=5) developed a survey and pilot tested for face and content validity. The instrument included demographics, forced choice and open-ended questions. The pre/post survey was administered to 301 participants of 21 Florida APTA CCIP courses with 5 trainers from 2009-2011. Quantitative survey data were collated, tabulated, and summarized comparing pre/post data. Narrative data was analyzed for codes and themes, synthesized, re-contextualized and triangulated by trainers then cross-compared with APTA CCIP objectives and trainer expertise. The qualitative insights were presented with resulting primary themes and subthemes. Results informed the study purposes with a clear determination of the reasons participants attend the APTA CCIP, the pre-course goals and post learning outcomes. Participants overwhelmingly recommend the APTA CCIP and most receive support from employers with geographic course location being a prime reason for course selection. Precourse learning goals included 5 over-arching themes, with few sub-themes; while post learning outcomes generated 12 specific themes with numerous subthemes. APTA CCIP-credentialed clinical instructors are achieving numerous learning outcomes immediately applicable for clinical education.

The advantages and limitations of seeking sex online: a comparison of reasons given for online and offline sexual liaisons by men who have sex with men.

PubMed

Ross, Michael W; Rosser, B R Simon; McCurdy, Sheryl; Feldman, Jamie

2007-02-01

The Internet has developed as a major site for sexual activity, both cybersex and for making contacts for sex in real life (IRL). As part of a major study of HIV-risk behavior on the Internet and IRL , we obtained on-line responses from 1,017 Latino men who have sex with men (MSM) in the U.S. Open-ended questions solicited responses regarding whether respondents preferred to meet sexual partners first IRL (48.4%), on the Internet (31.6%), or "it depends" (20%), and "why?". Data were analyzed by theme, with themes grouped into overarching domains. Data indicate that for those preferring the Internet, themes represented were ease of Internet use, its advantages for people who were shy, and its anonymity, safety, the excitement and opportunity for experimentation of Internet contact, ability to avoid interpersonal contact, and control of visuals and the environment. Reasons for preferring meeting IRL included some of the same themes, but emphasizing the importance of a "real presence" and the possibility to build a relationship. Where "it depends", key themes were contextual: mood, time, setting, alcohol and drug use, sexual needs and urgency, and relationship intentions. Antagonistic advantages were often noted for cybersex and IRL. These data suggest that motivations for making Internet sexual contact in MSM are complex, depend on the context and nature of the relationship sought, and that the Internet has allowed the development of a class of sexual contacts located between IRL and fantasy.

From will to live to will to die: oncologists, nurses, and social workers identification of suicidality in cancer patients.

PubMed

Granek, Leeat; Nakash, Ora; Ariad, Samuel; Chen, Wendy; Birenstock-Cohen, Shira; Shapira, Shahar; Ben-David, Merav

2017-12-01

The purpose of this research was to examine how oncologists, nurses, and social workers identify suicidality in cancer patients. Sixty-one healthcare professionals (23 oncologists, 18 social workers, and 20 nurses) at two academic cancer centers were interviewed using an in-depth interview guide. This was a qualitative study based on grounded theory methodology. Analysis involved line-by-line coding, with categories and themes emerging from participants' narratives. Suicidality in cancer patients exists on a wide spectrum that ranges from an active will to live to an active will to die. Four phases were identified that included: (A) a strong will to live expressed in themes of active treatments, seeking second opinions, overtreatment, and alternative treatments; (B) a decreasing will to live indicated in themes of mental health distress and physical pain and suffering; (C) a readiness to die expressed in themes of mental health distress, previous mental health diagnoses, physical pain, avoiding more suffering, preserving quality of life in old age, nearing end of life, lack of social support, and maintaining a sense of control; and (D) a will to die indicated in themes of euthanasia and active suicidality. Suicidality in cancer patients exists on a continuum. Cancer patients fluctuate on this spectrum depending on circumstances such as degree of suffering, their personalities and life circumstances, and whether they are nearing the end of life. Results of the study emphasize the need to collect more context specific data on suicidality among cancer patients and the importance of early integration of psychosocial and palliative care in the cancer treatment trajectory.

'Sharing things with people that I don't even know': help-seeking for psychological symptoms in injured Black men in Philadelphia.

PubMed

Jacoby, Sara F; Rich, John A; Webster, Jessica L; Richmond, Therese S

2018-04-01

Psychological distress is common in survivors of traumatic injury, yet across United States' trauma systems, it is rare that standard injury care integrates psychological evaluation and professional mental healthcare. The purpose of this study was to explore help-seeking for psychological symptoms in injured Black men living in Philadelphia. A subset of a cohort of 551 injured Black men admitted to a Trauma Center in Philadelphia participated in qualitative interviews that explored their perceptions of psychological symptoms after injury and the factors that guided their decision to seek professional mental health help. Data from 32 participants were analyzed for narrative and thematic content. Three overarching themes emerged: (1) facilitators of help-seeking, (2) barriers to help-seeking, and (3) factors underlying the decision not to consider professional help. Five participants felt that their injury-related psychological distress was severe enough to merit professional help despite any perceived barriers. Seventeen participants identified systemic and interpersonal obstacles to professional help that prevented them from seeking this kind of care. These included: financial constraints, limited access to mental healthcare services, and fear of the judgments of mental healthcare professionals. Ten participants would not consider professional help; these men perceived a lack of need and sufficiency in their existing social support networks. Research is needed to inform or identify interventions that diminish the impact of barriers to care, and identify from whom, where, and how professional mental health help might be more effectively offered to injured Black men in recovery environments like Philadelphia.

A Systematic Literature Review of the Information-Seeking Behavior of Dentists in Developed Countries.

PubMed

Isham, Amy; Bettiol, Silvana; Hoang, Ha; Crocombe, Leonard

2016-05-01

Understanding the information-seeking behavior of dentists may inform ways to increase the dentist uptake of evidence-based research for clinical decision making and the practice of evidence-based dentistry, but no systematic review of dentist information-seeking behavior has been conducted. This review aimed to synthesize the best available evidence on where and how dentists seek information. A literature search of Web of Science, Scopus, PubMed, and reference lists of English language studies from the Organization for Economic Cooperation and Development countries of dentists' information-seeking behavior published between 2002 and 2014 was conducted. Selected articles were assessed using mixed methods analysis, and the data extracted were thematically synthesized. Nine studies met the inclusion criteria, and four main themes were identified: dentists' difficulty translating evidence-based resources into clinical practice; dentists' preference for face-to-face meetings, collegial discussion, and print materials over evidence-based resources; dentists' perceptions of the validity of evidence-based resources and the role of specialist and experienced dentists as information sources for general and less experienced dentists; and differences between early and late adopters of research evidence. Dentists in these studies tended to adopt new materials/techniques after discussion with a colleague, a dental specialist, or a respected dental expert. These dentists also reported lacking time, experience, skills, and confidence to find and use evidence-based resources. Many of the dentists studied were cautious about making decisions based on documentary sources like literature reviews and preferred to seek advice from an experienced or specialist colleague or to participate in face-to-face meetings.