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The adiabatic theory of galaxy formation in neutrino-dominated universes is reviewed. Collisionless damping leads to a density fluctuation spectrum with a cutoff, the nonlinear evolution of which naturally results in the formation of pancakes, strings and voids.
A general nonlinear function G(X) describing the biasing of primordial Gaussian density fluctuations is considered. Arbitrary N-point correlations of the biased field are calculated in the form of a series expansion in terms of the correlations of the Gaussian field. The observed scaling of the three point correlations in the galaxy distribution is satisfied, but the scaling coefficient Q has a nontrivial value Q = J2/J12, where Jk is the k-th term in the Hermite expansion of G(X). The three point function is always accompanied by a cubic term Q3ξ1ξ2ξ3, independent of the functional form of the biasing. Its absence in the cluster 3-point correlations may be observable, in which case it rules out biasing as the major amplification mechanism of galaxy and cluster correlations.
The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4 m telescope with a large field of view ( ~ 0.3 deg2) and fine angular resolution (0.11”). WFIRST’s Wide Field Instrument (WFI) will obtain images in the Z, Y, J, H, F184, W149 (wide) filter bands, and grism spectra of the same large field of view. The data volume of the WFIRST Science Archive is expected to reach a few Petabytes. We describe plans to enable users to find the data of interest and, if needed, to analyze the data in situ using sophisticated software tools provided by the archive. As preparation, we are building a mini-archive that will help us to define realistic science requirements and to design the full WFIRST Science Archive.
We present estimates of cosmological parameters from the application of the Karhunen-Loève transform to the analysis of the 3D power spectrum of density fluctuations using Sloan Digital Sky Survey galaxy redshifts. We use Ωmh and fb = Ωb/Ωm to describe the shape of the power spectrum, σL8g for the (linearly extrapolated) normalization, and β to parametrize linear theory redshift space distortions. on scales k ≤ 0.16hMpc--1, our maximum likelihood values are Ωmh = 0.264 ± 0.043, fb = 0.286 ± 0.065, σL8g = 0.966 ± 0.048, and β = 0.45 ± 0.12. When we take a prior on Ωb from WMAP, we find Ωmh = 0.207 ± 0.030, which is in excellent agreement with WMAP and 2dF. This indicates that we have reasonably measured the gross shape of the power spectrum but we have difficulty breaking the degeneracy between and Ωmh and fb because the baryon oscillations are not resolved in the current spectroscopic survey window function.
The next generation of spectroscopic surveys, both Galactic and extra-galactic (e.g., SDSS, 2dF), present the challenge of classifying spectra in an efficient and objective manner. The standard approach to this problem has been to visually classify spectra based on a number of spectral features (e.g., the equivalent widths of emission lines). The size of new spectral surveys (> 106 galaxies) and the desire to compare the luminosity and environments of galaxies with their spectral properties make these techniques infeasible. We describe here an automated classification scheme that is being developed for the SDSS.
Astronomy is about to undergo a major paradigm shift, with data sets becoming larger, and more homogeneous, for the first time designed in the top-down fashion. In a few years it may be much easier to “dial-up” a part of the sky, when we need a rapid observation than wait for several months to access a (sometimes quite small) telescope. With several projects in multiple wavelengths under way, like the SDSS, 2MASS, GSC-2, POSS2, ROSAT, FIRST and DENIS projects, each surveying a large fraction of the sky, the concept of having a “Digital Sky,” with multiple, TB size databases interoperating in a seamless fashion is no longer an outlandish idea. More and more catalogs will be added and linked to the existing ones, query engines will become more sophisticated, and astronomers will have to be just as familiar with mining data as with observing on telescopes.
Heterogeneous catalytic materials and electrodes are used for (electro)chemical transformations, including those important for energy storage and utilization.1, 2 Due to the heterogeneous nature of these materials, activity measurements with sufficient spatial resolution are needed to obtain structure/activity correlations across the different surface features (exposed facets, step edges, lattice defects, grain boundaries, etc.). These measurements will help lead to an understanding of the underlying reaction mechanisms and enable engineering of more active materials. Because (electro)catalytic surfaces restructure with changing environments,1 it is important to perform measurements in operando. Sub-diffraction fluorescence microscopy is well suited for these requirements because it can operate in solution with resolution down to a few nm. We have applied sub-diffraction fluorescence microscopy to a thin cell containing an electrocatalyst and a solution containing the redox sensitive dye p-aminophenyl fluorescein to characterize reaction at the solid-liquid interface. Our chosen dye switches between a nonfluorescent reduced state and a one-electron oxidized bright state, a process that occurs at the electrode surface. This scheme is used to investigate the activity differences on the surface of polycrystalline Pt, in particular to differentiate reactivity at grain faces and grain boundaries. Ultimately, this method will be extended to study other dye systems and electrode materials.
The fields of research covered by Division VIII and its two Commissions have experienced remarkable progress over the last several years. This is due at least in part to the proliferation of major new observational facilities, and the addition of the several 8-m class telescopes presently being completed and new space facilities which will have a huge impact in the years to come. Many of the important recent scientific developments are summarized on the following pages in the reports of Commission 28 and Commission 47. These reports have been prepared in the “short” form, and are intended both to present the major scientific highlights and the most important conference proceedings and reviews for further reading.
Cosmology is one of the most dynamically evolving areas of astrophysics today. Twenty years ago the estimates of the amplitude of the primordial fluctuations were about 10-3, almost a factor of 100 off of today’s measurements. Ten years ago we could only hope for high precision measurements of large scale structure, there were less than 5000 redshifts measured, and only a handful of normal galaxies with z > 1 were known. Computer models of structure formation had just begun to consider non-power-law spectra based on physical models like hot/cold dark matter. As a consequence there was considerable freedom in adjusting parameters in the various galaxy formation scenarios. In contrast, many of today’s debates are about factors of 2 and soon we will be arguing about 10% differences. The Harrison-Zeldovich shape of the primordial fluctuation spectrum, first derived from philosophical arguments can now be quantified from detections of fluctuations by COBE. The number of available redshifts is beyond 50,000, and soon we will have redshift surveys surpassing 1 million galaxies. N-body simulations are becoming more sophisticated, of higher resolution, and incorporating complex gas dynamics.
This essay examines the fascination with bodily conversion that characterizes recent HBO programming. Dramas and comedies like True Blood, Veep, Silicon Valley, and True Detective describe human forms in various states of transformation: into a menagerie of supernatural creatures, polling data, digital information and, even, the landscape of the American South. These transformations anticipate and seek to rationalize the exchange of the programs in which they appear into and out of diverse forms of Time Warner brand equity – even as they rehearse anxieties that the network's famed “quality” diminishes in the face of such exchanges. Female characters bear the brunt of this reflexivity; their forcibly contorted and monetized bodies figure the temporary material form assumed by otherwise liquid equity as it moves within Time Warner and, ultimately, over Internet lines and into the viewer's home. The network's famed misogyny is, in this respect, self-conscious and idiosyncratic, and reveals something essential about the incoherence of HBO's parent company at the moment that the network discovers new pathways for the direct distribution of its product.
We show that redshift-space distortions of galaxy correlations have a strong effect on correlation functions with the signature of the Baryon Acoustic Oscillations (BAO). Near the line of sight, the features become sharper as a result of redshift-space distortions. We analyze the SDSS DR7 main-galaxy sample (MGS), splitting the sample into slices 2.5 deg on the sky in various rotations. Measuring 2D correlation functions in each slice, we do see a sharp bump along the line of sight. Using Mexican-hat wavelets, we localize it to (110 ± 10) h − 1 Mpc and estimate its significance at about 4σ.
Vietnam enjoys the richest natural resources and favourable conditions for agricultural development including poultry production. Backyard chicken production is considered as a traditional system in Vietnam, as it has a short production cycle and requires low investment. Despite the increase of semi-intensive and intensive farming, the self-sufficient backyard farming system is still practised by 84-85% of rural families in the Northeast-Northwest of Vietnam and approximately 42-71% of those in the Southeast-Mekong River Delta regions. Breeds raised in such systems are mostly popular local chicken breeds which accounted for over 70% of the country's total chicken population in 2007. In this paper, more than 30 native Vietnamese chicken breeds with their origin and endangered status are listed and the breeding traditions related to these native breeds are discussed. Moreover, some proposals are given for a particular conservation strategy regarding the possibilities to utilise the native Vietnamese chicken breeds in sustainable rural farming. It has been concluded that governmental conservation efforts should meet the natural way to save the local native breeds by local inhabitants. In this way, a sustainable on-farm chicken conservation pattern can be elaborated not only for Vietnam but also for the countries or regions which have similarly rich, valuable biodiversity, agro-biodiversity and agricultural traditions. For this, local researchers should be encouraged to study economic traits, veterinary status, and all special characteristics of the local breeds in the frames of an official, national gene conservation programme.
Extreme value statistics (EVS) is applied to the pixelized distribution of galaxy luminosities in the Sloan Digital Sky Survey (SDSS). We analyze the DR8 Main Galaxy Sample (MGS) as well as the Luminous Red Galaxy Sample (LRGS). A non-parametric comparison of the EVS of the luminosities with the Fisher-Tippett-Gumbel distribution (limit distribution for independent variables distributed by the Press-Schechter law) indicates a good agreement provided uncertainties arising both from the finite size of the samples and from the sample size distribution are accounted for. This effectively rules out the possibility of having a finite maximum cutoff luminosity.
We present the results of space-based photometric and ground-based spectroscopic observing campaigns on the γ-ray binary LS 5039. The new orbital and physical parameters of the system are similar to former results, except we found a lower eccentricity. Our MOST-data show that any broad-band optical photometric variability at the orbital period is below the 2 mmag level. Light curve simulations support the lower value of eccentricity and imply that the mass of the compact object is higher than 1.8 M⊙.
We present detailed analysis of mid-infrared (MIR) data for 9 type II-P supernovae from the public Spitzer database. Spectral energy distributions (SEDs) from observed fluxes are fitted with simple models to get basic information about the dust as the presumed source of MIR radiation. We found two SNe, 2005ad and 2005af, which likely have newly-formed dust in their environment, while in the other seven cases the observed MIR flux may originate from pre-existing circumstellar or interstellar dust.
A synthesis is presented of two recent studies on modelling the nonlinear neuro-mechanical hearing processes in mosquitoes and in mammals. In each case, a hierarchy of models is considered in attempts to understand data that shows nonlinear amplification and compression of incoming sound signals. The insect’s hearing is tuned to the vicinity of a single input frequency. Nonlinear response occurs via an arrangement of many dual capacity neuro-mechanical units called scolopidia within the Johnston’s organ. It is shown how the observed data can be captured by a simple nonlinear oscillator model that is derived from homogenization of a more complex model involving a radial array of scolopidia. The physiology of the mammalian cochlea is much more complex, with hearing occurring via a travelling wave along a tapered, compartmentalized tube. Waves travel a frequency-dependent distance along the tube, at which point they are amplified and “heard”. Local models are reviewed for the pickup mechanism, within the outer hair cells of the organ of Corti. The current debate in the literature is elucidated, on the relative importance of two possible nonlinear mechanisms: active hair bundles and somatic motility. It is argued that the best experimental agreement can be found when the nonlinear terms include longitudinal coupling, the physiological basis of which is described. A discussion section summarizes the lessons learnt from both studies and attempts to shed light on the more general question of what constitutes a good mathematical model of a complex physiological process.