The Nonlinear Cosmological Matter Power Spectrum with Massive Neutrinos I: The Halo Model

Measurements of the linear power spectrum of galaxies have placed tight constraints on neutrino masses. We extend the framework of the halo model of cosmological nonlinear matter clustering to include the effect of massive neutrino infall into cold dark matter (CDM) halos. The magnitude of the effect of neutrino clustering for three degenerate mass neutrinos with m_nu=0.9 eV is of order ~1%, within the potential sensitivity of upcoming weak lensing surveys. In order to use these measurements to further constrain--or eventually detect--neutrino masses, accurate theoretical predictions of the nonlinear power spectrum in the presence of massive neutrinos will be needed, likely only possible through high-resolution multiple particle (neutrino, CDM and baryon) simulations.Comment: v2: matches PRD versio

Deconstructing Videotaped Instruction for Online Delivery: Instructional Design in Reverse

This paper examines a project in which videotaped face-to-face class sessions were converted into interactive instructional modules for Internet delivery. The development of the online class involved the challenge of teaching the advanced Microsoft Office Suite – normally skills learned hands-on – to distance learners. Sixteen interactive modules were eventually produced by using a process the authors describe as the instructional design in reverse. This paper discusses the importance of the proper application of instructional design theory, the actual production processes used for developing the modules, and important lessons learned in working with interactive multimedia course content for online delivery.This paper examines a project in which videotaped face-to-face class sessions were converted into interactive instructional modules for Internet delivery. The development of the online class involved the challenge of teaching the advanced Microsoft Office Suite – normally skills learned hands-on – to distance learners. Sixteen interactive modules were eventually produced by using a process the authors describe as the instructional design in reverse. This paper discusses the importance of the proper application of instructional design theory, the actual production processes used for developing the modules, and important lessons learned in working with interactive multimedia course content for online delivery

The Impact of Multi-Level Governance on Energy Performance in the Current Dutch Housing Stock \ud

The housing sector is responsible for 33% of total CO2 emissions in the Netherlands. As such, large reductions in CO2 emissions can be gained by increasing the energy performance in the existing housing stock. Yet, several barriers make this difficult. Renovation investments and maintenance costs are high while badly needed norms for energy improvement are absent. Furthermore, market developments and sectoral policies reflect a complex institutional environment in which many actors are interdependent, but also lack an individual sense of urgency regarding energy consumption. In this article, we try to determine how multi-level governance in Dutch housing affects the outcomes of policies aimed at CO2-reduction in the existing housing stock. We examined two housing sectors in the Netherlands: social housing and owner occupancy. We focus on policy implementation problems in the early 2000s. It turns out that the complex multi-level environment severely impedes the realization of ambitious policy goals.\ud \u

Three-Phased Wake Vortex Decay

A detailed parametric study is conducted that examines vortex decay within turbulent and stratified atmospheres. The study uses a large eddy simulation model to simulate the out-of-ground effect behavior of wake vortices due to their interaction with atmospheric turbulence and thermal stratification. This paper presents results from a parametric investigation and suggests improvements for existing fast-time wake prediction models. This paper also describes a three-phased decay for wake vortices. The third phase is characterized by a relatively slow rate of circulation decay, and is associated with the ringvortex stage that occurs following vortex linking. The three-phased decay is most prevalent for wakes imbedded within environments having low-turbulence and near-neutral stratification

Amplification of simian retroviral sequences from human recipients of baboon liver transplants

Investigations into the use of baboons as organ donors for human transplant recipients, a procedure called xenotransplantation, have raised the specter of transmitting baboon viruses to humans and possibly establishing new human infectious diseases. Retrospective analysis of tissues from two human transplant recipients with end-stage hepatic disease who died 70 and 27 days after the transplantation of baboon livers revealed the presence of two simian retroviruses of baboon origin, simian foamy virus (SFV) and baboon endogenous virus (BaEV), in multiple tissue compartments. The presence of baboon mitochondrial DNA was also detected in these same tissues, suggesting that xenogeneic 'passenger leukocytes' harboring latent or active viral infections had migrated from the xenografts to distant sites within the human recipients. The persistence of SFV and BaEV in human recipients throughout the posttransplant period underscores the potential infectious risks associated with xenotransplantation

Using BBN in cosmological parameter extraction from CMB: a forecast for Planck

Data from future high-precision Cosmic Microwave Background (CMB) measurements will be sensitive to the primordial Helium abundance $Y_p$. At the same time, this parameter can be predicted from Big Bang Nucleosynthesis (BBN) as a function of the baryon and radiation densities, as well as a neutrino chemical potential. We suggest to use this information to impose a self-consistent BBN prior on $Y_p$ and determine its impact on parameter inference from simulated Planck data. We find that this approach can significantly improve bounds on cosmological parameters compared to an analysis which treats $Y_p$ as a free parameter, if the neutrino chemical potential is taken to vanish. We demonstrate that fixing the Helium fraction to an arbitrary value can seriously bias parameter estimates. Under the assumption of degenerate BBN (i.e., letting the neutrino chemical potential $\xi$ vary), the BBN prior's constraining power is somewhat weakened, but nevertheless allows us to constrain $\xi$ with an accuracy that rivals bounds inferred from present data on light element abundances.Comment: 14 pages, 4 figures; v2: minor changes, matches published versio

Recovery of Large Angular Scale CMB Polarization for Instruments Employing Variable-delay Polarization Modulators

Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a $300$ K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residual modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating $1/f$ noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of $r=0.01$. Indeed, $r<0.01$ is achievable with commensurately improved characterizations and controls.Comment: 13 pages, 13 figures, 1 table, matches published versio

Advanced Three Level Approximation for Numerical Treatment of Cosmological Recombination

New public numerical code for fast calculations of the cosmological recombination of primordial hydrogen-helium plasma is presented. The code is based on the three-level approximation (TLA) model of recombination and allows us to take into account some fine physical effects of cosmological recombination simultaneously with using fudge factors. The code can be found at http://www.ioffe.ru/astro/QC/CMBR/atlant/atlant.htmlComment: 10 pages, 7 figures, 1 table, to be submitted to MNRA

Primordial helium recombination. I. Feedback, line transfer, and continuum opacity

Precision measurements of the cosmic microwave background temperature anisotropy on scales ℓ>500 will be available in the near future. Successful interpretation of these data is dependent on a detailed understanding of the damping tail and cosmological recombination of both hydrogen and helium. This paper and two companion papers are devoted to a precise calculation of helium recombination. We discuss several aspects of the standard recombination picture, and then include feedback, radiative transfer in He i lines with partial redistribution, and continuum opacity from H i photoionization. In agreement with past calculations, we find that He ii recombination proceeds in Saha equilibrium, whereas He i recombination is delayed relative to Saha due to the low rates connecting excited states of He i to the ground state. However, we find that at z<2200 the continuum absorption by the rapidly increasing H i population becomes effective at destroying photons in the He i 21Po-11S line, causing He i recombination to finish around z≃1800, much earlier than previously estimated

Long-term production of greenhouse gases from exposed continental shelves and oceanic islands during Quaternary glacial periods

The EPICA Dome C ice core in Antarctica has yielded an 800,000-year record of atmospheric carbon dioxide and methane composition from the Middle Pleistocene climatic transition to the present. In this record, there is a sharp increase in both carbon dioxide and methane immediately following the glacial maxima during the glacial periods which to date remains difficult to explain. We will present evidence to show that the exposed continental shelves and ...published_or_final_versio