Imprint of DESI fiber assignment on the anisotropic power spectrum of emission line galaxies

The Dark Energy Spectroscopic Instrument (DESI), a multiplexed fiber-fed spectrograph, is a Stage-IV ground-based dark energy experiment aiming to measure redshifts for 29 million Emission-Line Galaxies (ELG), 4 million Luminous Red Galaxies (LRG), and 2 million Quasi-Stellar Objects (QSO). The survey design includes a pattern of tiling on the sky and the locations of the fiber positioners in the focal plane of the telescope, with the observation strategy determined by a fiber assignment algorithm that optimizes the allocation of fibers to targets. This strategy allows a given region to be covered on average five times for a five-year survey, but with coverage varying between zero and twelve, which imprints a spatially-dependent pattern on the galaxy clustering. We investigate the systematic effects of the fiber assignment coverage on the anisotropic galaxy clustering of ELGs and show that, in the absence of any corrections, it leads to discrepancies of order ten percent on large scales for the power spectrum multipoles. We introduce a method where objects in a random catalog are assigned a coverage, and the mean density is separately computed for each coverage factor. We show that this method reduces, but does not eliminate the effect. We next investigate the angular dependence of the contaminated signal, arguing that it is mostly localized to purely transverse modes. We demonstrate that the cleanest way to remove the contaminating signal is to perform an analysis of the anisotropic power spectrum $P(k,\mu)$ and remove the lowest $\mu$ bin, leaving $\mu>0$ modes accurate at the few-percent level. Here, $\mu$ is the cosine of the angle between the line-of-sight and the direction of $\vec{k}$. We also investigate two alternative definitions of the random catalog and show they are comparable but less effective than the coverage randoms method.Comment: Submitted to JCA

The adoption potential of biomass transfer and improved fallow practices in Eastern Uganda : Determining profitable and feasible options from a farmer perspective

No Abstract

On the Refinement of Write-Ahead Logging

Many hackers worldwide would agree that, had it not been for Smalltalk, the synthesis of voice-over-IP might never have occurred. After years of unfortunate research into mas- sive multiplayer online role-playing games, we verify the understanding of XML. we prove not only that the UNIVAC computer and journaling file systems are always incompati- ble, but that the same is true for virtual ma- chines

Post-temporary ligation intra-operative mesenteric portovenography: comparison with computed tomographic angiography for investigation of portosystemic shunts

Objectives: Comparison of pre-operative computed tomographic angiography and post-temporary full ligation intraoperative mesenteric portovenography for the documentation of the intrahepatic portal vasculature in patients with single extrahepatic portosystemic shunts. Methods: Retrospective study of patients with extrahepatic portosystemic shunts that underwent preoperative computed tomographic angiography and intra-operative mesenteric portovenography after temporary full ligation of an identified shunt vessel. Studies were compared for appearance of the intrahepatic portal vasculature. Results: Fourteen dogs and five cats were included in the study with various single congenital extrahepatic portosystemic shunts variations. With the exception of those shunts involving the right gastric vein, the identification of the intrahepatic arborisation was similar on both modalities. Subjectively, however, there was improved contrast enhancement, as well as slight enlargement of the intrahepatic portal vasculature, on portovenography compared to computed tomographic angiography. Clinical significance: This paper shows that computed tomographic angiography cannot replace intraoperative mesenteric portovenography after temporary full ligation, which provides information regarding the development of intrahepatic portal vascularity. It is a practical and dynamic procedure providing results which are instantaneously available at the time of surgery. In addition, TFL-IOMP confirmed both that the shunting vessel had been recognised and only one vessel was present

The Global Threat of Counterfeit Drugs: Why Industry and Governments Must Communicate the Dangers

The production of substandard and fake drugs is a vast and underreported problem, particularly affecting poorer countries. Cockburn and colleagues argue that the pharmaceutical industry and governments must both take actio

The mass-metallicity gradient relation of early-type galaxies

We present a newly observed relation between galaxy mass and radial metallicity gradients of early-type galaxies. Our sample of 51 early-type galaxies encompasses a comprehensive mass range from dwarf to brightest cluster galaxies. The metallicity gradients are measured out to one effective radius by comparing nearly all of the Lick absorption-line indices to recent models of single stellar populations. The relation shows very different behaviour at low and high masses, with a sharp transition being seen at a mass of ~ 3.5 x 10^10 M_sun (velocity dispersion of ~140 km/s, M_B ~ -19). Low-mass galaxies form a tight relation with mass, such that metallicity gradients become shallower with decreasing mass and positive at the very low-mass end. Above the mass transition point several massive galaxies have steeper gradients, but a clear downturn is visible marked by a broad scatter. The results are interpreted in comparison with competing model predictions. We find that an early star-forming collapse could have acted as the main mechanism for the formation of low-mass galaxies, with star formation efficiency increasing with galactic mass. The high-mass downturn could be a consequence of merging and the observed larger scatter a natural result of different merger properties. These results suggest that galaxies above the mass threshold of ~ 3.5 x 10^10 M_sun might have formed initially by mergers of gas-rich disc galaxies and then subsequently evolved via dry merger events. The varying efficiency of the dissipative merger-induced starburst and feedback processes have shaped the radial metallicity gradients in these high-mass systems.Comment: 5 pageg, 3 figures, accepted by ApJ Lette

An algorithm for the direct reconstruction of the dark matter correlation function from weak lensing and galaxy clustering

The clustering of matter on cosmological scales is an essential probe for studying the physical origin and composition of our Universe. To date, most of the direct studies have focused on shear-shear weak lensing correlations, but it is also possible to extract the dark matter clustering by combining galaxy-clustering and galaxy-galaxy-lensing measurements. In this study we develop a method that can constrain the dark matter correlation function from galaxy clustering and galaxy-galaxy-lensing measurements, by focusing on the correlation coefficient between the galaxy and matter overdensity fields. To generate a mock galaxy catalogue for testing purposes, we use the Halo Occupation Distribution approach applied to a large ensemble of N-body simulations to model pre-existing SDSS Luminous Red Galaxy sample observations. Using this mock catalogue, we show that a direct comparison between the excess surface mass density measured by lensing and its corresponding galaxy clustering quantity is not optimal. We develop a new statistic that suppresses the small-scale contributions to these observations and show that this new statistic leads to a cross-correlation coefficient that is within a few percent of unity down to 5 Mpc/h. Furthermore, the residual incoherence between the galaxy and matter fields can be explained using a theoretical model for scale-dependent bias, giving us a final estimator that is unbiased to within 1%. We also perform a comprehensive study of other physical effects that can affect the analysis, such as redshift space distortions and differences in radial windows between galaxy clustering and weak lensing observations. We apply the method to a range of cosmological models and show the viability of our new statistic to distinguish between cosmological models.Comment: 23 pages, 14 figures, accepted by PRD; minor changes to V1, 1 new figure, more detailed discussion of the covariance of the new ADSD statisti

Testing Standard Cosmology with Large Scale Structure

The galaxy power spectrum contains information on the growth of structure, the growth rate through redshift space distortions, and the cosmic expansion through baryon acoustic oscillation features. We study the ability of two proposed experiments, BigBOSS and JDEM-PS, to test the cosmological model and general relativity. We quantify the latter result in terms of the gravitational growth index \gamma, whose value in general relativity is \gamma\approx 0.55. Significant deviations from this value could indicate new physics beyond the standard model of cosmology. The results show that BigBOSS (JDEM-PS) would be capable of measuring \gamma with an uncertainty \sigma(\gamma) = 0.043 (0.054), which tightens to \sigma(\gamma) = 0.031 (0.038) if we include Stage III data priors, marginalizing over neutrino mass, time varying dark energy equation of state, and other parameters. For all dark energy parameters and related figures of merit the two experiments give comparable results. We also carry out some studies of the influence of redshift range, resolution, treatment of nonlinearities, and bias evolution to enable further improvement.Comment: 9 pages, 12 tables, 1 figure; v3 matches MNRAS accepted versio

Expression of recombinant human ceruloplasmin – an absolute requirement for splicing signals in the expression cassette

AbstractWe report the successful expression of recombinant human ceruloplasmin which was made possible by inclusion of splicing signals in the expression vector. Ceruloplasmin cDNA expressed from the vector pNUT in baby hamster kidney cells gave protein yields of 0.03 mg/l which increased to 15 mg/l with splicing signals present. The defect in expression from the intronless cDNA is due to complete retention of ceruloplasmin mRNA in cell nuclei. The block to cytoplasmic export is alleviated by splicing signals, allowing full expression of the mRNA