bluuebunny/crossref_metadata_2025 huggingface dataset:
Children in the Syrian Civil War: the Familial, Educational, and Public Health Impact of Ongoing Violence
Authors: Elsafti Abdallah Mohamed , van Berlaer Gerlant , Al Safadi Mohammad , Debacker Michel , Buyl Ronald , Redwan Atef , Hubloue Ives
Published: October 2016

Objective

The Syrian civil war since 2011 has led to one of the most complex humanitarian emergencies in history. The objective of this study was to document the impact of the conflict on the familial, educational, and public health state of Syrian children.

Methods

A cross-sectional observational study was conducted in May 2015. Health care workers visited families with a prospectively designed data sheet in 4 Northern Syrian governorates.

Results

The 1001 children included in this study originated from Aleppo (41%), Idleb (36%), Hamah (15%), and Lattakia (8%). The children’s median age was 6 years (range, 0-15 years; interquartile range, 3-11 years), and 61% were boys. Almost 20% of the children were internally displaced, and 5% had deceased or missing parents. Children lacked access to safe drinking water (15%), appropriate sanitation (23%), healthy nutrition (16%), and pediatric health care providers (64%). Vaccination was inadequate in 72%. More than half of school-aged children had no access to education. Children in Idleb and Lattakia were at greater risk of having unmet public health needs. Younger children were at greater risk of having an incomplete vaccination state.

Conclusions

After 4 years of civil war in Syria, children have lost parents, live in substandard life quality circumstances, and are at risk for outbreaks because of worsening vaccination states and insufficient availability of health care providers. (Disaster Med Public Health Preparedness. 2016;10:874–882)
Cold War Sewing Machines: Production and Consumption in 1950s China and Japan
Authors: Finnane Antonia
Published: October 2016

With the “consumption turn” in the humanities and the social sciences, a phenomenon evident in English-language scholarship from the 1980s onward, production ceased to command the attention it had once received from historians. A recent (2012) study of the sewing machine in modern Japan by Harvard historian Andrew Gordon demonstrates the effects: what could feasibly have been published under the title “Making Machinists” was instead marketed as “Fabricating Consumers.” What does it mean to talk about consumers in 1950s Japan, a time and place of hard work, thrift, and restraint? For Gordon an important premise was the role of women in the postwar economy. This provides a point of departure from which to explore the ideologies and practices of production and consumption across the Cold War dividing line between “consumerist” and “productionist” regimes in East Asia. The Cold War was a time of sharp differences between the two societies, but also a time of shared preoccupations with productivity and national growth. In their different political contexts, Japanese and Chinese women were acting out many of the same roles.
A School within a School of War: Workers Making, Learning and Teaching about History
Authors: Grossman Jonathan
Published: October 2016

In June 1988 hotel-workers in Cape Town were amongst many dismissed in the then biggest stay-away against planned anti-union attacks. For months they met daily, organising their struggle for reinstatement: the site of an ongoing collective process of radical worker education for liberation. Workers shared this through a process of documentation and solidarity celebrating their collective agency, reflecting on past, making current, and envisioning future history. A different capitalist market-driven education for competitiveness now dominates postapartheid South Africa. A reflection written in 1994 illuminates the denigration of working class collectivism, successfully resisted by the dismissed workers but even then developing.
Class Formation and Workers’ Attitudes toward Education:La Pensée Ouvrière(1948) by Georges Duveau
Authors: Hanagan Michael
Published: October 2016

La pensée ouvrièrere pendant la second république et le second empire,Georges Duveau's classic but largely-forgotten study of French artisanal workers, focuses on changing attitudes toward work and education between 1848 and 1870, years which Duveau himself lauded as exceptionally fertile and creative in French social thought. How to explain such extraordinary fecundity? Partly, it can be explained by intensified police repression after Napoleon III’s coup, when the educational institutions of workers were repressed and they had to design new ones under the eyes of a suspicious state. Perhaps a more important factor, one suggested by the recent work of Thomas Piketty, is the ever-growing need to produce workers capable catering to the ever more sophisticated needs of the fabulously wealthy. The highly skilled artisanal production in Paris combined with the growth of factories created the distinctive conditions of French economic growth.
Working Youth and Education in Postwar Greece: Night Schools as Arenas of Political Struggle and Cultural Practices
Authors: Lampropoulou Dimitra
Published: October 2016

The Working Pupils’ Association of High Schools was founded in 1960s’ Greece as an organization of working boys and girls who attended secondary evening schools after having finished their daily waged work. Acting simultaneously as a conventional union and as a collective that encouraged artistic activity, the association elaborated new meanings about the relation between work, education, and youth. The postwar period saw the rapid expansion of secondary schooling to the lower classes, which affected deeply both youth and the working class. However, significant attention has not yet been paid to pupils generally, let alone to those of the working class. Addressing this lacuna, this article suggests a new perspective on the relation between the histories of youth, class, political acculturation, and social change in the second half of the twentieth century.
Combination of spindle and first polar body chromosome images for the enhanced prediction of developmental potency of mouse metaphase II oocytes
Authors: Sugano Yukou , Yazawa Manami , Takino Sachio , Niimura Sueo , Yamashiro Hideaki
Published: October 2016

The objective of this study was to classify spindle and first polar body (PB1) chromosome images in ovulated mouse oocytes over time to predict the developmental competence of metaphase II (MII) oocytes. Oocytes were collected at 12, 15, 20, and 25 h after human chorionic gonadotropin (hCG) injection, and stained for spindle tubulin, chromosomes, and PB1 chromosomes. MII spindle morphology was classified as tapered type or barrel type and PB1 chromosomes were categorized as aggregated, separated, dot, or collapsed. To determine whether differences in spindle and PB1 images in MII oocytes are associated with fertilization success, we performed in vitro fertilization (IVF) at various times after hCG injection. Barrel-type spindles and aggregate-type PB1 were dominant at 12 h after hCG injection. Oocyte spindles collected 1 h after injection were tapered, and PB1 chromosomes were separated. At 20 and 25 h after treatment, spindle and PB1 images were classified as collapsed. The rate of development to 2-cell embryos after IVF did not differ between the 12 h and 15 h treatments; however, it was significantly lower for the 25 h treatment than for other treatments. The rates of development to blastocysts at 12, 15, 20, and 25 h after hCG injection were 61, 46, 42, and 9%, respectively. MII oocytes with barrel-type spindles and aggregate-type PB1 had high rates of fertilization and blastocyst development, and spindle and PB1 characteristics were correlated with the outcomes of IVF and embryo culture. These results suggested that images of spindles combined with those of PB1 chromosomes enable the prediction of oocytic and/or embryonic quality.
I Will Register and Vote, If You Teach Me How: A Field Experiment Testing Voter Registration in College Classrooms
Authors: Bennion Elizabeth A. , Nickerson David W.
Published: October 2016

College students are young, have little or no history of voting, and are residentially mobile, which makes them a population in great need of registering to vote. Universities have a civic, pedagogical, and legal obligation to register their students to vote. In 2006, we conducted a controlled experiment across 16 college campuses to test the efficacy of classroom presentations to increase voter registration. The 25,256 students across more than 1,026 classrooms were randomly assigned to one of three conditions: (1) a control group receiving no presentation; (2) a presentation by a professor; and (3) a presentation by a student volunteer. Verifying registration and voter turnout from a national voter database, we found that both types of presentations increased overall registration by 6 percentage points and turnout rates by approximately 2.6 percentage points. These results demonstrated that universities can take simple steps to engage their students in politics.
A Calamitous Compact
Authors: DeWitt Darin , Schwartz Thomas
Published: October 2016

The National Popular Vote Interstate Compact (joined so far by ten states and DC) would replace the current presidential-election system, based on the electoral college and the winner-take-all rule, with nationwide plurality rule, and it would do so by changes in state law, not a Constitutional amendment. The mischief that would create (especially procedural instability, noncompliant electors, nation-wide recounts, vote manipulation, and narrowed support), the compact’s questionable Constitutionality, the weakness of its defense, and the availability of less calamitous alternatives are reasons enough to reject it.
A Not-So-Calamitous Compact: A Response to DeWitt and Schwartz
Authors: Koza John R.
Published: October 2016

This paper answers 24 criticisms of the National Popular Vote interstate compact in Darin DeWitt and Thomas Schwartz’s paper entitled “A Calamitous Compact” (found elsewhere in this issue).
An Outsider’s Inside View of the Iowa Caucuses
Authors: Andersen David J.
Published: October 2016

Every four years the state of Iowa leads off the presidential primary season by voting in its famed First in the Nation caucuses. And every four years academics, journalists, and citizens question whether Iowa is a suitable candidate to start the primary season. As a lifelong New Jerseyan, I joined this opposition view, and favored a different system—whether regional primaries, a rotating first state, or, well, anything else. Then, just three years ago I moved from New Jersey to Iowa, providing me an inside view of the state’s role in the nominating process and forcing me to see the caucuses in a new light. What I have seen, and will discuss here, are my reasons for changing my mind.
Polling the Pollsters: A Survey of Academic Survey Organizations
Authors: Fernandez Kenneth E. , Husser Jason A. , Macdonald Mary G.
Published: October 2016

Organizations conducting survey research have remained of vital importance to the social sciences. However, these organizations increasingly face new challenges and opportunities. Survey operations housed in universities and colleges may face special challenges. We present a poll of pollsters, an original survey of leaders of academic survey organizations in the United States. Results explore the various methods used by academic survey organizations and perceptions of challenges in today’s academic and research environments. Responses provide an overview of the career path of academic survey leaders and how those leaders understand the primary missions of their organizations. We conclude with a discussion relevant to social scientists interested in the dynamics of operating these important academic research centers.
Campaign Simulation for American Government: An Active Learning Approach to Campaigns and Elections
Authors: Alberda Gayle
Published: October 2016

Instructors of American government are challenged with teaching students from a variety of disciplines. Utilizing active learning methods captures students in a manner traditional lectures cannot. For this study I employed an experimental design to assess a campaign simulation used in an Introduction to American Government course. Results show the simulation aided in students’ learning about campaigns and elections.
Yes, But Did They Learn Anything? An Experimental Investigation of Voter Decision Making on Foreign Policy Issues
Authors: Sievert Jacqueline M. , McDonald Michael K. , Fagan Charles J. , Michelsen Niall
Published: October 2016

Do non-graded, one-time, short presentations by a panel of professors on foreign policy issues affect voting behavior among students? Did the panel itself contribute to students’ understanding of the importance of foreign policy in evaluating candidates? Did presentations lead to changes in students’ candidate preferences? And, finally, did the event lead to sustained changes in students’ preferences? We find that even though issues of foreign policy tend not to be front and center in American elections, when young voters are presented with information about candidate’s foreign policy positions, as we did in this study, it does seem to have an impact on which candidate they plan on voting for.
Reflections: The Michigan Four and Their Study of American Voters: A Biography of a Collaboration
Authors: Weisberg Herbert F.
Published: October 2016

The publication ofThe American Voterin 1960 revolutionized the study of American voting behavior. Its University of Michigan authors, Angus Campbell, Philip E. Converse, Warren E. Miller, and Donald E. Stokes, were to share thousands of citations, but they were four different people, with different backgrounds, different personalities, and different career trajectories afterwards. This paper presents a chronological biography ofThe American Voter, from assembling the research team, through writing the book, to its aftermath, and ending with brief perspectives on each author.
Conditional Arbiters: The Limits of Political Party Influence in Presidential Nominations
Authors: Steger Wayne P.
Published: October 2016

The 2016 Republican presidential nomination challenges arguments about political party insiders’ influence on the outcome. This article argues, first, that party insider influence is conditional on the participation, coalescence, and timing of party stakeholders behind a front-runner during the invisible primary, and second, that party insider influence has probably declined since the 2000 presidential election. Data on endorsements by elite elected officials in open presidential nominations from 1984 to 2016 show that party insiders’ participation and convergence of support behind the front-runner is less extensive than what was found by Cohen, Karol, Noel, and Zaller (2008), though the data sets differ. Party insiders participate and unify more readily when the party coalition is stable and there is a candidate in the race who has demonstrable national support. Party elites remain on the sidelines when the party coalition is divided or when there is uncertainty about the appeal of candidates (Ryan 2011; Whitby 2014). The potency of insider endorsements likely has declined with the rise of social media, the changing campaign finance landscape, and the reemergence of populism in each party.
Dietary intakes and diet quality according to levels of organic food consumption by French adults: cross-sectional findings from the NutriNet-Santé Cohort Study
Authors: Baudry Julia , Allès Benjamin , Péneau Sandrine , Touvier Mathilde , Méjean Caroline , Hercberg Serge , Galan Pilar , Lairon Denis , Kesse-Guyot Emmanuelle
Published: October 2016

Objective

We aimed to assess dietary profiles of adults from the NutriNet-Santé cohort according to different levels of organic food consumption using detailed self-reported data on organic food intakes.

Design

Food intakes were obtained using an organic food frequency questionnaire (Org-FFQ). The participants were ranked into five groups (quintiles, Q) according to the proportion of organic foods in their diet. To determine diet quality, two scores were computed reflecting adherence to food-based recommendations (mPNNS-GS) and the probability of adequate nutrient intake (PANDiet). Relationships between levels of organic food consumption and dietary characteristics were assessed using multivariable-adjusted ANCOVA models.

Setting

The NutriNet-Santé Study.

Subjects

French adults from the NutriNet-Santé Study (n 28 245).

Results

Intakes of foods of plant origin increased along with the contribution of organic foods to the diet while a reverse trend was identified for dairy products, cookies and soda (P-trend<0·0001). The diet quality scores increased from Q1 (mPNNS-GS, 7·89 (se 0·02); PANDiet: 63·04 (se 0·11)) to Q5 (mPNNS-GS, 8·78 (se 0·02); PANDiet, 69·37 (se 0·10)). Overall, high organic food consumers exhibited better diet quality, although intermediate organic food consumers showed better adherence to specific nutritional recommendations related to animal products.

Conclusions

The study provides new insights into the understanding of organic food consumption as a part of a healthy diet and sheds some light on the dietary profiles of different categories of organic food consumers. These results underline strong dietary behaviour correlates associated with organic food consumption that should be controlled for in future aetiological studies on organic foods and health.
Yakov Zeldovich and the Cosmic Web Paradigm
Authors: Einasto Jaan
Published: October 2016

I discuss the formation of the modern cosmological paradigm. In more detail I describe the early study of dark matter and cosmic web and the role of Yakov Zeldovich in the formation of the present concepts on these subjects.
Ya. B. Zeldovich (1914-1987) Chemist, Nuclear Physicist, Cosmologist
Authors: Sahni Varun
Published: October 2016

Yakov Borisovich Zeldovich was remarkably talented.† His active scientific career included major contributions in fields as diverse as chemical physics (adsorption & catalysis), the theory of shock waves, thermal explosions, the theory of flame propogation, the theory of combustion & detonation, nuclear & particle physics, and, during the latter part of his life: gravitation, astrophysics and cosmology (Zeldovich 1992).
The Peak/Dip Picture of the Cosmic Web
Authors: Rossi Graziano
Published: October 2016

The initial shear field plays a central role in the formation of large-scale structures, and in shaping the geometry, morphology, and topology of the cosmic web. We discuss a recent theoretical framework for the shear tensor, termed the ‘peak/dip picture’, which accounts for the fact that halos/voids may form from local extrema of the density field – rather than from random spatial positions; the standard Doroshkevich's formalism is generalized, to include correlations between the density Hessian and shear field at special points in space around which halos/voids may form. We then present the ‘peak/dip excursion-set-based’ algorithm, along with its most recent applications – merging peaks theory with the standard excursion set approach.
Dynamics of The Tranquil Cosmic Web
Authors: Nusser Adi
Published: October 2016

The phase space distribution of matter out to ∼ 100 \rm Mpc is probed by two types of observational data: galaxy redshift surveys and peculiar motions of galaxies. Important information on the process of structure formation and deviations from standard gravity have been extracted from the accumulating data. The remarkably simple Zel'dovich approximation is the basis for much of our insight into the dynamics of structure formation and the development of data analyses methods. Progress in the methodology and some recent results is reviewed.
Collisionless Dynamics and the Cosmic Web
Authors: Hahn Oliver
Published: October 2016

I review the nature of three-dimensional collapse in the Zeldovich approximation, how it relates to the underlying nature of the three-dimensional Lagrangian manifold and naturally gives rise to a hierarchical structure formation scenario that progresses through collapse from voids to pancakes, filaments and then halos. I then discuss how variations of the Zeldovich approximation (based on the gravitational or the velocity potential) have been used to define classifications of the cosmic large-scale structure into dynamically distinct parts. Finally, I turn to recent efforts to devise new approaches relying on tessellations of the Lagrangian manifold to follow the fine-grained dynamics of the dark matter fluid into the highly non-linear regime and both extract the maximum amount of information from existing simulations as well as devise new simulation techniques for cold collisionless dynamics.
Statistics of Caustics in Large-Scale Structure Formation
Authors: Feldbrugge Job L. , Hidding Johan , van de Weygaert Rien
Published: October 2016

The cosmic web is a complex spatial pattern of walls, filaments, cluster nodes and underdense void regions. It emerged through gravitational amplification from the Gaussian primordial density field. Here we infer analytical expressions for the spatial statistics of caustics in the evolving large-scale mass distribution. In our analysis, following the quasi-linear Zel'dovich formalism and confined to the 1D and 2D situation, we compute number density and correlation properties of caustics in cosmic density fields that evolve from Gaussian primordial conditions. The analysis can be straightforwardly extended to the 3D situation. We moreover, are currently extending the approach to the non-linear regime of structure formation by including higher order Lagrangian approximations and Lagrangian effective field theory.
Non-linear description of massive neutrinos in the framework of large-scale structure formation
Authors: Dupuy Hélène
Published: October 2016

There is now no doubt that neutrinos are massive particles fully involved in the non-linear growth of the large-scale structure of the universe. A problem is that they are particularly difficult to include in cosmological models because the equations describing their behavior in the non-linear regime are cumbersome and difficult to handle. In this manuscript I present a new method allowing to deal with massive neutrinos in a very simple way, based on basic conservation laws. This method is still valid in the non-linear regime. The key idea is to describe neutrinos as a collection of single-flow fluids instead of seeing them as a single hot multi-flow fluid. In this framework, the time evolution of neutrinos is encoded in fluid equations describing macroscopic fields, just as what is done for cold dark matter. Although valid up to shell-crossing only, this approach is a further step towards a fully non-linear treatment of the dynamical evolution of neutrinos in the framework of large-scale structure growth.
Mapping the Cosmic Web with the largest all-sky surveys
Authors: Bilicki Maciej , Peacock John A. , Jarrett Thomas H. , Cluver Michelle E. , Steward Louise
Published: October 2016

Our view of the low-redshift Cosmic Web has been revolutionized by galaxy redshift surveys such as 6dFGS, SDSS and 2MRS. However, the trade-off between depth and angular coverage limits a systematic three-dimensional account of the entire sky beyond the Local Volume (z< 0.05). In order to reliably map the Universe to cosmologically significant depths over the full celestial sphere, one must draw on multiwavelength datasets and state-of-the-art photometric redshift techniques. We have undertaken a dedicated program of cross-matching the largest photometric all-sky surveys – 2MASS, WISE and SuperCOSMOS – to obtain accurate redshift estimates of millions of galaxies. The first outcome of these efforts – the 2MASS Photometric Redshift catalog (2MPZ, Bilickiet al. 2014a) – has been publicly released and includes almost 1 million galaxies with a mean redshift ofz=0.08. Here we summarize how this catalog was constructed and how using the WISE mid-infrared sample together with SuperCOSMOS optical data allows us to push to redshift shells ofz∼ 0.2 –0.3 on unprecedented angular scales. Our catalogs, with ∼ 20 million sources in total, provide access to cosmological volumes crucial for studies of local galaxy flows (clustering dipole, bulk flow) and cross-correlations with the cosmic microwave background such as the integrated Sachs-Wolfe effect or lensing studies.
Tracing high redshift cosmic web with quasar systems
Authors: Einasto Maret
Published: October 2016

We study the cosmic web at redshifts 1.0 ≤ ≤ 1.8 using quasar systems based on quasar data from the SDSS DR7 QSO catalogue. Quasar systems were determined with a friend-of-friend (FoF) algorithm at a series of linking lengths. At the linking lengths l ≤ 30h-1Mpc the diameters of quasar systems are smaller than the diameters of random systems, and are comparable to the sizes of galaxy superclusters in the local Universe. The mean space density of quasar systems is close to the mean space density of local rich superclusters. At larger linking lengths the diameters of quasar systems are comparable with the sizes of supercluster complexes in our cosmic neighbourhood. The richest quasar systems have diameters exceeding 500hMpc. Very rich systems can be found also in random distribution but the percolating system which penetrate the whole sample volume appears in quasar sample at smaller linking length than in random samples showing that the large-scale distribution of quasar systems differs from random distribution. Quasar system catalogues at our web pages (http://www.aai.ee/maret/QSOsystems.html) serve as a database to search for superclusters of galaxies and to trace the cosmic web at high redshifts.
Dynamics of galaxy structures in the Local Volume
Authors: Karachentsev I. D.
Published: October 2016

I consider a sample of ‘Updated Nearby Galaxy Catalog’ that contains eight hundred objects within 11 Mpc. Environment of each galaxy is characterized by a tidal index Θ1 depending on separation and mass of the galaxy Main Disturber (=MD). The UNGC galaxies with a common MD are ascribed to its ‘suite’ and ranked according to their Θ1. Fifteen the most populated suites contain more than half of the UNGC sample. The fraction of MDs among the brightest galaxies is almost 100% and drops to 50% at M_B = -18 mag. The observational properties of galaxies accumulated in UNGC are used to derive orbital masses of giant galaxies via motions of their satellites. The average orbital-to-stellar mass ratio for them is MorbM* ≃ 30, corresponding to the mean local density of matter Ωm ≃ 0.09, i.e 1/3 of the global cosmic one. The dark-to-stellar mass ratio for the Milky Way and M31 is typical for other neighboring giant galaxies.
The Dark Matter filament between Abell 222/223
Authors: Dietrich Jörg P. , Werner Norbert , Clowe Douglas , Finoguenov Alexis , Kitching Tom , Miller Lance , Simionescu Aurora
Published: October 2016

Weak lensing detections and measurements of filaments have been elusive for a long time. The reason is that the low density contrast of filaments generally pushes the weak lensing signal to unobservably low scales. To nevertheless map the dark matter in filaments exquisite data and unusual systems are necessary. SuprimeCam observations of the supercluster system Abell 222/223 provided the required combination of excellent seeing images and a fortuitous alignment of the filament with the line-of-sight. This boosted the lensing signal to a detectable level and led to the first weak lensing mass measurement of a large-scale structure filament. The filament connecting Abell 222 and Abell 223 is now the only one traced by the galaxy distribution, dark matter, and X-ray emission from the hottest phase of the warm-hot intergalactic medium. The combination of these data allows us to put the first constraints on the hot gas fraction in filaments.
Studying structure formation and evolution with strong-lensing galaxy groups
Authors: Foëx Gaël , Motta Veronica , Limousin Marceau , Verdugo Tomas , Gastaldello Fabio
Published: October 2016

We present the analysis of a sample of strong-lensing galaxy group candidates. Our main findings are: confirmation of group-scale systems, complex light distributions, presence of large-scale structures in their surroundings, and evidence of a strong-lensing bias in the mass-concentration relation. We also report the detection of the first 'Bullet group'.
The Evolving Shape of Galaxy Clusters
Authors: Just Dennis W. , Yee H. K. C. , Muzzin Adam , Wilson Gillian , Gilbank David G. , Gladders Michael
Published: October 2016

We present the first measurement of the evolution of the apparent projected shape of galaxy clusters from 0.2≲ z≲2. We measure the ellipticities (εcl) of homogeneously selected galaxy clusters over this wide redshift range. We confirm the predictions of N-body simulations that clusters are more elongated at higher redshift, finding the mean projected ellipticity changes linearly from 0.36±0.01 to 0.25±0.01 over that range. The fraction of relaxed clusters (defined as having εcl<0.2) is 9+5-3% at z∼1.8, steadily increasing to 42+7-6% by z∼0.3. Because more spherical clusters have a higher degree of virialization, our result shows significant evolution in the degree of cluster virialization over cosmic time.
Evolution of the galaxy correlation function at redshifts 0.2 < z < 3
Authors: Sołtan Andrzej M.
Published: October 2016

We determine the auto-correlation function (ACF) of galaxies using massive deep galaxy surveys for which distances to individual objects are assessed using photometric redshifts. The method is applied to the 2deg COSMOS survey of ~ 300000 galaxies with i + < 25 and zph ≲ 3. The distance estimates based on photometric redshifts are not sufficiently accurate to be directly used to determine the ACF. Nevertheless, the photometric redshifts carry statistical information on the data distribution on (very) large scales. The investigation of the surface distribution of galaxies in several redshift (=distance) bins allows us to determine the spatial (3D) ACF over the redshift range of 0.2 - 3.2 or look back time of 2.4 - 11.5 Gy.
Local Large-Scale Structure and the Assumption of Homogeneity
Authors: Keenan Ryan C. , Barger Amy J. , Cowie Lennox L.
Published: October 2016

Our recent estimates of galaxy counts and the luminosity density in the near-infrared (Keenan et al. 2010, 2012) indicated that the local universe may be under-dense on radial scales of several hundred megaparsecs. Such a large-scale local under-density could introduce significant biases in the measurement and interpretation of cosmological observables, such as the inferred effects of dark energy on the rate of expansion. In Keenan et al. (2013), we measured the K-band luminosity density as a function of distance from us to test for such a local under-density. We made this measurement over the redshift range 0.01 < z < 0.2 (radial distances D ~ 50 - 800 h70−1 Mpc). We found that the shape of the K-band luminosity function is relatively constant as a function of distance and environment. We derive a local (z < 0.07, D < 300 h70−1 Mpc) K-band luminosity density that agrees well with previously published studies. At z > 0.07, we measure an increasing luminosity density that by z ~ 0.1 rises to a value of ~ 1.5 times higher than that measured locally. This implies that the stellar mass density follows a similar trend. Assuming that the underlying dark matter distribution is traced by this luminous matter, this suggests that the local mass density may be lower than the global mass density of the universe at an amplitude and on a scale that is sufficient to introduce significant biases into the measurement of basic cosmological observables. At least one study has shown that an under-density of roughly this amplitude and scale could resolve the apparent tension between direct local measurements of the Hubble constant and those inferred by Planck team. Other theoretical studies have concluded that such an under-density could account for what looks like an accelerating expansion, even when no dark energy is present.
Constraints on radio source clustering towards galaxy clusters: application for cm-wavelength simulations of blind sky surveys
Authors: Lew Bartosz
Published: October 2016

We derive constraints on radio source clustering towards Planck-selected galaxy clusters using the NVSS point source catalog. The constraint can be used for making a more realistic Sunyaev-Zeldovich effect (SZE) mocks, calculating predictions of detectable clusters count and for quantifying source confusion in radio surveys.
Cosmicflows-2
Authors: Tully R. Brent , Courtois Hélène M. , Hoffman Yehuda , Pomarède Daniel
Published: October 2016

A compendium of over 8000 galaxy distances has been accumulated. Distance measurements permit the separation of observed velocities into cosmic expansion and peculiar velocity components. Only the radial component of peculiar velocities can be measured and individual errors are large, but a Wiener Filter procedure permits the reconstruction of three-dimensional motions and the density field that is responsible for these motions. A coherent flow pervades the entire domain of ± 15,000 km/s. Techniques are discussed for the separation of local and tidal components of the flow. Laniakea supercluster is identified as a region of contiguous infalling flows.
Re-examination of Large Scale Structure & Cosmic Flows
Authors: Davis Marc , Nusser Adi
Published: October 2016

Comparison of galaxy flows with those predicted from the local galaxy distribution ended as an active field after two analyses came to vastly different conclusions 25 years ago, but that was due to faulty data. All the old results are therefore suspect. With new data collected in the last several years, the problem deserves another look. The goal is to explain the 640 km/s dipole anisotropy of the CMBR. For this we analyze the gravity field inferred from the enormous data set derived from the 2MASS collection of galaxies (Huchra et al. 2005), and compare it to the velocity field derived from the well calibrated SFI++ Tully-Fisher catalog (Springob et al. 2007). Using the “Inverse Method” to minimize Malmquist biases, within 10,000 km/s the gravity field is seen to predict the velocity field (Davis et al. 2011) to remarkable consistency. This is a beautiful demonstration of linear perturbation theory and is fully consistent with standard values of the cosmological variables.
Towards an accurate model of redshift-space distortions: a bivariate Gaussian description for the galaxy pairwise velocity distributions
Authors: Bianchi Davide , Chiesa Matteo , Guzzo Luigi
Published: October 2016

As a step towards a more accurate modelling of redshift-space distortions (RSD) in galaxy surveys, we develop a general description of the probability distribution function of galaxy pairwise velocities within the framework of the so-called streaming model. For a given galaxy separation , such function can be described as a superposition of virtually infinite local distributions. We characterize these in terms of their moments and then consider the specific case in which they are Gaussian functions, each with its own mean μ and variance σ2. Based on physical considerations, we make the further crucial assumption that these two parameters are in turn distributed according to a bivariate Gaussian, with its own mean and covariance matrix. Tests using numerical simulations explicitly show that with this compact description one can correctly model redshift-space distorsions on all scales, fully capturing the overall linear and nonlinear dynamics of the galaxy flow at different separations. In particular, we naturally obtain Gaussian/exponential, skewed/unskewed distribution functions, depending on separation as observed in simulations and data. Also, the recently proposed single-Gaussian description of redshift-space distortions is included in this model as a limiting case, when the bivariate Gaussian is collapsed to a two-dimensional Dirac delta function. More work is needed, but these results indicate a very promising path to make definitive progress in our program to improve RSD estimators.
Redshift-Space Distortions and f(z) from Group-Galaxy Correlations
Authors: Mohammad F. G. , de la Torre S. , Guzzo L. , Bianchi D. , Peacock J. A.
Published: October 2016

We investigate the accuracy achievable on measurements of the the growth rate of structure f(z) using redshift-space distortions (RSD), when (a) these are measured on the group-galaxy cross correlation function; (b) the latter is expanded over a modified version of the conventional spherical armonics, “truncated multipole moments”. Simulation results give first indications that this combination can push systematic errors on f(z) below 3%, using scales r ⩾ 10h−1 Mpc.
Quasars as tracers of cosmic flows
Authors: Modzelewska J. , Czerny B. , Bilicki M. , Hryniewicz K. , Krupa M. , Petrogalli F. , Pych W. , Kurcz A. , Udalski A.
Published: October 2016

Quasars, as the most luminous persistent sources in the Universe, have broad applications for cosmological studies. In particular, they can be employed to directly measure the expansion history of the Universe, similarly to SNe Ia. The advantage of quasars is that they are numerous, cover a broad range of redshifts, up to z = 7, and do not show significant evolution of metallicity with redshift. The idea is based on the relation between the time delay of an emission line and the continuum, and the absolute monochromatic luminosity of a quasar. For intermediate redshift quasars, the suitable line is Mg II. Between December 2012 and March 2014, we performed five spectroscopic observations of the QSO CTS C30.10 (z = 0.900) using the South African Large Telesope (SALT), supplemented with photometric monitoring, with the aim of determining the variability of the line shape, changes in the total line intensity and in the continuum. We show that the method is very promising.
The Lyα forest and the Cosmic Web
Authors: Meiksin Avery
Published: October 2016

The accurate description of the properties of the Lyman-α forest is a spectacular success of the Cold Dark Matter theory of cosmological structure formation. After a brief review of early models, it is shown how numerical simulations have demonstrated the Lyman-α forest emerges from the cosmic web in the quasi-linear regime of overdensity. The quasi-linear nature of the structures allows accurate modeling, providing constraints on cosmological models over a unique range of scales and enabling the Lyman-α forest to serve as a bridge to the more complex problem of galaxy formation.
Finding and characterising WHIM structures using the luminosity density method
Authors: Nevalainen Jukka , Liivamägi L. J. , Tempel E. , Branchini E. , Roncarelli M. , Giocoli C. , Heinämäki P. , Saar E. , Bonamente M. , Einasto M. , Finoguenov A. , Kaastra J. , Lindfors E. , Nurmi P. , Ueda Y.
Published: October 2016

We have developed a new method to approach the missing baryons problem. We assume that the missing baryons reside in a form of Warm Hot Intergalactic Medium, i.e. the WHIM. Our method consists of (a) detecting the coherent large scale structure in the spatial distribution of galaxies that traces the Cosmic Web and that in hydrodynamical simulations is associated to the WHIM, (b) mapping its luminosity into a galaxy luminosity density field, (c) using numerical simulations to relate the luminosity density to the density of the WHIM, (d) applying this relation to real data to trace the WHIM using the observed galaxy luminosities in the Sloan Digital Sky Survey and 2dF redshift surveys. In our application we find evidence for the WHIM along the line of sight to the Sculptor Wall, at redshifts consistent with the recently reported X-ray absorption line detections. Our indirect WHIM detection technique complements the standard method based on the detection of characteristic X-ray absorption lines, showing that the galaxy luminosity density is a reliable signpost for the WHIM. For this reason, our method could be applied to current galaxy surveys to optimise the observational strategies for detecting and studying the WHIM and its properties. Our estimates of the WHIM hydrogen column density NH in Sculptor agree with those obtained via the X-ray analysis. Due to the additional NH estimate, our method has potential for improving the constrains of the physical parameters of the WHIM as derived with X-ray absorption, and thus for improving the understanding of the missing baryons problem.
Magnetogenesis at Cosmic Dawn
Authors: Durrive J-B. , Langer M.
Published: October 2016

We present a mechanism for generating cosmological magnetic fields during the Epoch of Reionization, based on the photoionization of intergalactic hydrogen. A general formula is presented, together with an example numerical application which yields magnetic field strengths between 10−23 to 10−19 G on intersource scales. This mechanism, which operates all along Reionization around any ionizing source, participates to the premagnetization of the whole intergalactic medium. Also, the spatial configuration of these fields may help discriminate them from those produced by other mechanisms in future observations.
Hierarchical formation of Dark Matter Halos near the Free Streaming Scale, and Their Implications on Indirect Dark Matter Search
Authors: Ishiyama Tomoaki
Published: October 2016

The smallest dark matter halos are formed first in the early universe. According to recent studies, the central density cusp is much steeper in these halos than in larger halos and scales as ρ ∝ r−(1.5−1.3). We present results of very large cosmological N-body simulations of the hierarchical formation and evolution of halos over a wide mass range, beginning from the formation of the smallest halos. We confirmed early studies that the inner density cusps are steeper in halos at the free streaming scale. The cusp slope gradually becomes shallower as the halo mass increases. The slope of halos 50 times more massive than the smallest halo is approximately -1.3. The concentration parameter is nearly independent of halo mass, and ruling out simple power law mass-concentration relations. The steeper inner cusps of halos near the free streaming scale enhance the annihilation luminosity of a Milky Way sized halo between 12 to 67%.
How do galaxies build up their spin in the cosmic web?
Authors: Welker Charlotte , Dubois Yohan , Pichon Christophe , Devriendt Julien , Peirani Sebastien
Published: October 2016

Using the Horizon-AGN simulation we find a mass dependent spin orientation trend for galaxies: the spin of low-mass, rotation-dominated, blue, star-forming galaxies are preferentially aligned with their closest filament, whereas high-mass, velocity dispersion- supported, red quiescent galaxies tend to possess a spin perpendicular to these filaments. We explore the physical mechanisms driving galactic spin swings and quantify how much mergers and smooth accretion re-orient them relative to their host filaments.
Gaseous discs at intermediate redshifts from kinematic data modelling
Authors: Kipper R. , Tamm A. , Tenjes P. , Tempel E.
Published: October 2016

Our purpose is to measure thickness of gaseous discs in 0 < z < 1.2 galaxies. As gas dispersions are sensitive to scale height of gaseous discs, we model the kinematics of galaxies using Jeans equations. The resulting thicknesses of gaseous discs at higher redshifts are more thicker (and arbitrary) while nearby ones are thinner. We also found that clumpiness of galaxy is a possible indicator of the gas disc thickness.
Alignments of galaxies and halos in hydrodynamical simulations
Authors: Pahwa Isha , Libeskind Noam I.
Published: October 2016

We use a 200 h−1Mpc cosmological hydrodynamical simulation to examine the alignments of galaxies with respect to the host halo. We do separate study for the different components of the halo, such as stars, gas and dark matter. We show that angular momentum of gas is more aligned with the angular momentum of host halo compared with the stellar component.
Metallicity evolution in mergers of disk galaxies with black holes
Authors: Rantala Antti , Johansson Peter H.
Published: October 2016

We use the TreeSPH simulation code Gadget-3 including a recently improved smoothed particle hydrodynamics (SPH) module, a detailed metallicity evolution model and sophisticated subresolution feedback models for supernovae and supermassive black holes in order to study the metallicity evolution in disk galaxy mergers. In addition, we examine the simulated morphology, star formation histories, metallicity gradients and kinematic properties of merging galaxies and merger remnants. We will compare our simulation results with observations of the early-type Centaurus A galaxy and the currently colliding Antennae galaxies.
Void Dynamics
Authors: Padilla Nelson D. , Paz Dante , Lares Marcelo , Ceccarelli Laura , Lambas Diego Garcí a , Cai Yan-Chuan , Li Baojiu
Published: October 2016

Cosmic voids are becoming key players in testing the physics of our Universe.
Here we concentrate on the abundances and the dynamics of voids as these are among the best candidates
to provide information on cosmological parameters. Cai, Padilla & Li (2014)
use the abundance of voids to tell apart Hu & Sawicki f(R) models from General Relativity. An interesting
result is that even though, as expected, voids in the dark matter field are emptier in f(R) gravity due to the fifth force expelling
away from the void centres, this result is reversed when haloes are used to find voids. The abundance of voids in this case
becomes even lower in f(R) compared to GR for large voids. Still, the differences are significant and this
provides a way to tell apart these models. The velocity field differences between f(R) and GR, on the other hand, are
the same for halo voids and for dark matter voids.
Paz et al. (2013), concentrate on the velocity profiles around voids. First they show the necessity
of four parameters to describe the density profiles around voids given two distinct void
populations, voids-in-voids and voids-in-clouds. This profile is used to predict peculiar velocities around voids,
and the combination of the latter with void density profiles allows the construction of model
void-galaxy cross-correlation functions with redshift space distortions. When these models
are tuned to fit the measured correlation functions for voids and galaxies in the Sloan
Digital Sky Survey, small voids are found to be of the void-in-cloud type, whereas larger
ones are consistent with being void-in-void. This is a novel result that is obtained
directly from redshift space data around voids. These profiles can be used to
remove systematics on void-galaxy Alcock-Pacinsky tests coming from redshift-space distortions.
Measuring the growth rate of structure around cosmic voids
Authors: Hawken A. J. , Michelett D. , Granett B. , Iovino A. , Guzzo L.
Published: October 2016

Using an algorithm based on searching for empty spheres we identified 245 voids in the VIMOS Public Extragalactic Redshift Survey (VIPERS). We show how by modelling the anisotropic void-galaxy cross correlation function we can probe the growth rate of structure.