Sub-degree CMB anisotropies from inflationary bubbles

It is well known that processes of first order phase transitions may have occurred in the inflationary era. If one or more occurred well before the end of inflation, the nucleated bubbles are stretched to large scales and the primordial power spectrum contains a scale dependent non-Gaussian component provided by the remnants of the bubbles. We predict the anisotropies in the cosmic microwave background (CMB) induced by inflationary bubbles. We build a general analytic model for describing a bubbly perturbation; we evolve each Fourier mode using the linear theory of perturbations from reheating until decoupling; we get the CMB anisotropies by considering the bubbly perturbation intersecting the last scattering surface. The CMB image of an inflationary bubble is a series of concentric isothermal rings of different color (sign of $\delta T/T$) on the scale of the sound horizon at decoupling ($\le 1^{o}$ in the sky); the resulting anisotropy is therefore strongly non-Gaussian. The mean amplitude of $\delta T/T$ for a bubble of size $L$ follows the known estimates for linear perturbations, $\delta T/T\simeq\delta\rho /\rho\cdot (L/H^{-1})^{2}$. In particular, bubbles with size corresponding to the seeds of the observed large scale voids (tens of comoving Mpc) induce an interesting pattern of CMB anisotropies on the sub-degree angular scale, to be further investigated and compared with the forthcoming high resolution CMB maps provided by the MAP and the Planck experiments.Comment: 10 pages, 5 postscript figures, accepted by Ap.

Peculiar Velocities of Nonlinear Structure: Voids in McVittie Spacetime

As a study of peculiar velocities of nonlinear structure, we analyze the model of a relativistic thin-shell void in the expanding universe. (1) Adopting McVittie (MV) spacetime as a background universe, we investigate the dynamics of an uncompensated void with negative MV mass. Although the motion itself is quite different from that of a compensated void, as shown by Haines & Harris (1993), the present peculiar velocities are not affected by MV mass. (2) We discuss how precisely the formula in the linear perturbation theory applies to nonlinear relativistic voids, using the results in (1) as well as the previous results for the homogeneous background (Sakai, Maeda, & Sato 1993). (3) We re-examine the effect of the cosmic microwave background radiation. Contrary to the results of Pim & Lake (1986, 1988), we find that the effect is negligible. We show that their results are due to inappropriate initial conditions. Our results (1)-(3) suggest that the formula in the linear perturbation theory is approximately valid even for nonlinear voids.Comment: 12 pages, aastex, 4 ps figures separate, Fig.2 added, to appear in Ap

Voids in the Large-Scale Structure

Voids are the most prominent feature of the LSS of the universe. Still, they have been generally ignored in quantitative analysis of it, essentially due to the lack of an objective tool to identify and quantify the voids. To overcome this, we present the Void-Finder algorithm, a novel tool for objectively quantifying galaxy voids. The algorithm classifies galaxies as either wall- or field-galaxies. Then it identifies voids in the wall-galaxy distribution. Voids are defined as continuous volumes that do not contain any wall-galaxies. The voids must be thicker than an adjustable limit, which is refined in successive iterations. We test the algorithm using Voronoi tessellations. By appropriate scaling of the parameters we apply it to the SSRS2 survey and to the IRAS 1.2 Jy. Both surveys show similar properties: ~50% of the volume is filled by the voids, which have a scale of at least 40 Mpc, and a -0.9 under-density. Faint galaxies populate the voids more than bright ones. These results suggest that both optically and IRAS selected galaxies delineate the same LSS. Comparison with the recovered mass distribution further suggests that the observed voids in the galaxy distribution correspond well to under-dense regions in the mass distribution. This confirms the gravitational origin of the voids.Comment: Submitted to ApJ; 33 pages, aaspp4 LaTeX file, using epsfig and natbib, 1 table, 12 PS figures. Complete gzipped version is available at http://shemesh.fiz.huji.ac.il/hagai/; uuencoded file is available at http://shemesh.fiz.huji.ac.il/papers/ep3.uu or ftp://shemesh.fiz.huji.ac.i

Comprehensive Immune Monitoring of Clinical Trials to Advance Human Immunotherapy.

The success of immunotherapy has led to a myriad of clinical trials accompanied by efforts to gain mechanistic insight and identify predictive signatures for personalization. However, many immune monitoring technologies face investigator bias, missing unanticipated cellular responses in limited clinical material. We present here a mass cytometry (CyTOF) workflow for standardized, systems-level biomarker discovery in immunotherapy trials. To broadly enumerate immune cell identity and activity, we established and extensively assessed a reference panel of 33 antibodies to cover major cell subsets, simultaneously quantifying activation and immune checkpoint molecules in a single assay. This assay enumerates ≥98% of peripheral immune cells with ≥4 positively identifying antigens. Robustness and reproducibility are demonstrated on multiple samples types, across two research centers and by orthogonal measurements. Using automated analysis, we identify stratifying immune signatures in bone marrow transplantation-associated graft-versus-host disease. Together, this validated workflow ensures comprehensive immunophenotypic analysis and data comparability and will accelerate biomarker discovery

Quantum walks-based simple authenticated quantum cryptography protocols for secure wireless sensor networks

Wireless sensor networks play a crucial role in various applications, ranging from environmental monitoring to industrial automation that require high levels of security. With the development of quantum technologies, many security mechanisms maybe hacked due to the promising capabilities of quantum computation. To address this challenge, quantum protocols have emerged as a promising solution for enhancing the security of wireless sensor communications. One of the common types of quantum protocols is quantum key distribution (QKD) protocols, which are investigated to allow two participants with fully quantum capabilities to share a random secret key, while semi-quantum key distribution (SQKD) protocols are designed to perform the same task using fewer quantum resources to make quantum communications more realizable and practical. Quantum walk plays an essential role in quantum computing, which is a universal quantum computational paradigm. In this work, we utilize the advantages of quantum walk to design three authenticated quantum cryptographic protocols to establish secure channels for data transmission between sensor nodes: the first one is authenticated quantum key distribution (AQKD), the second one is authenticated semi quantum key distribution (ASQKD) with one of the two participants having limited quantum capabilities, and the last one is authenticated semi-quantum key distribution but both legitimate users possess limited quantum resources. The advantages of the proposed protocols are that the partners can exchange several different keys with the same exchanged qubits, and the presented protocols depend on a one-way quantum communication channel. In contrast, all previously designed SQKD protocols rely on two-way quantum communication. Security analyses prove that the presented protocols are secure against various well known attacks and highly efficient. The utilization of the presented protocols in wireless sensor communications opens up new avenues for secure and trustworthy data transmission, enabling the deployment of resilient wireless sensor networks in critical applications. This work also paves the way for future exploration of quantum-based security protocols and their integration into wireless sensor networks for enhanced data protection

Effect of Void Network on CMB Anisotropy

We study the effect of a void network on the CMB anisotropy in the Einstein-de Sitter background using Thompson &Vishniac's model. We consider comprehensively the Sacks-Wolfe effect, the Rees-Sciama effect and the gravitational lensing effect. Our analysis includes the model of primordial voids existing at recombination, which is realized in some inflationary models associated with a first-order phase transition. If there exist primordial voids whose comoving radius is larger than $\sim10h^{-1}$Mpc at recombination, not only the Sachs-Wolfe effect but also the Rees-Sciama effect is appreciable even for multipoles l\lsim1000 of the anisotropy spectrum. The gravitational lensing effect, on the other hand, slightly smoothes the primary anisotropy; quantitatively, our results for the void model are similar to the previous results for a CDM model. All the effects, together, would give some constraints on the configuration or origin of voids with high-resolution data of the CMB anisotropy.Comment: 23 pages, latex, 12 eps figures, some calculations and discussions are added, to appear in ApJ 510 (1999

The DEEP2 Galaxy Redshift Survey: The Evolution of Void Statistics from z~1 to z~0

We present measurements of the void probability function (VPF) at z~1 using data from the DEEP2 Redshift Survey and its evolution to z~0 using data from the Sloan Digital Sky Survey (SDSS). We measure the VPF as a function of galaxy color and luminosity in both surveys and find that it mimics trends displayed in the two-point correlation function, $\xi$; namely that samples of brighter, red galaxies have larger voids (i.e. are more strongly clustered) than fainter, blue galaxies. We also clearly detect evolution in the VPF with cosmic time, with voids being larger in comoving units at z~0. We find that the reduced VPF matches the predictions of a `negative binomial' model for galaxies of all colors, luminosities, and redshifts studied. This model lacks a physical motivation, but produces a simple analytic prediction for sources of any number density and integrated two-point correlation function, \bar{\xi}. This implies that differences in the VPF across different galaxy populations are consistent with being due entirely to differences in the population number density and \bar{\xi}. The robust result that all galaxy populations follow the negative binomial model appears to be due to primarily to the clustering of dark matter halos. The reduced VPF is insensitive to changes in the parameters of the halo occupation distribution, in the sense that halo models with the same \bar{\xi} will produce the same VPF. For the wide range of galaxies studied, the VPF therefore does not appear to provide useful constraints on galaxy evolution models that cannot be gleaned from studies of \bar{\xi} alone. (abridged)Comment: 17 pages, 15 figures, ApJ accepte

Voids in the PSCz Survey and the Updated Zwicky Catalog

We describe an algorithm to detect voids in galaxy redshift surveys. The method is based on the void finder algorithm of El-Ad & Piran. We apply a series of tests to determine how accurately we are able to recover the volumes of voids using our detection method. We simulate voids of different ellipticity and find that if voids are approximately spherical, our algorithm will recover 100% of the volume of the void. The more elliptical the void, the smaller the fraction of the volume we can recover. We insist that voids lie completely within the survey. Voids close to the edge of the survey will therefore be underestimated in volume. By considering a deeper sample, we estimate the maximal sphere diameters are correct to within 30%. We apply the algorithm to the Point Source Catalogue Survey (PSCz) and the Updated Zwicky Catalog (UZC). The PSCz survey is an almost all-sky survey with objects selected from the IRAS catalog. The UZC covers a smaller area of sky but is optically selected and samples the structures more densely. We detect 35 voids in the PSCz and 19 voids in the UZC with diameter larger than 20h^{-1}Mpc. Using this minimum size threshold, voids have an average effective diameter of 29.8+-3.5 h^{-1}Mpc (PSCz) and 29.2+-2.7 h^{-1}Mpc (UZC) and that they are underdense regions with delta rho /rho values of -0.92+-0.03 (PSCz) and -0.96+-0.01(UZC) respectively. Using this quite stringent threshold for void definition, voids fill up to 40% of the volume of the universe.Comment: Accepted by ApJ to appear in the Feb 20th, 2002 issue. For a version with better resolution of Figures 4 and 5 see http://star-www.dur.ac.uk/~fhoyle/papers.htm

Improving the use of research evidence in guideline development: 15. Disseminating and implementing guidelines

BACKGROUND: The World Health Organization (WHO), like many other organisations around the world, has recognised the need to use more rigorous processes to ensure that health care recommendations are informed by the best available research evidence. This is the 15(th )of a series of 16 reviews that have been prepared as background for advice from the WHO Advisory Committee on Health Research to WHO on how to achieve this. OBJECTIVES: In this review we address strategies for the implementation of recommendations in health care. METHODS: We examined overviews of systematic reviews of interventions to improve health care delivery and health care systems prepared by the Cochrane Effective Practice and Organisation of Care (EPOC) group. We also conducted searches using PubMed and three databases of methodological studies for existing systematic reviews and relevant methodological research. We did not conduct systematic reviews ourselves. Our conclusions are based on the available evidence, consideration of what WHO and other organisations are doing and logical arguments. KEY QUESTIONS AND ANSWERS: What should WHO do to disseminate and facilitate the uptake of recommendations? • WHO should choose strategies to implement their guidelines from among those which have been evaluated positively in the published literature on implementation research • Because the evidence base is weak and modest to moderate effects, at best, can be anticipated, WHO should promote rigorous evaluations of implementation strategies. What should be done at headquarters, by regional offices and in countries? • Adaptation and implementation of WHO guidelines should be done locally, at the national or sub-national level. • WHO headquarters and regional offices should support the development and evaluation of implementation strategies by local authorities