Hemispherical power asymmetries in the WMAP 7-year low-resolution temperature and polarization maps

We test the hemispherical power asymmetry of the WMAP 7-year low-resolution temperature and polarization maps. We consider two natural estimators for such an asymmetry and exploit our implementation of an optimal angular power spectrum estimator for all the six CMB spectra. By scanning the whole sky through a sample of 24 directions, we search for asymmetries in the power spectra of the two hemispheres, comparing the results with Monte Carlo simulations drawn from the WMAP 7-year best-fit model. Our analysis extends previous results to the polarization sector. The level of asymmetry on the ILC temperature map is found to be compatible with previous results, whereas no significant asymmetry on the polarized spectra is detected. Moreover, we show that our results are only weakly affected by the a posteriori choice of the maximum multipole considered for the analysis. We also forecast the capability to detect dipole modulation by our methodology at Planck sensitivity.Comment: 7 pages, 9 figures. Accepted for publication in MNRA

Residual noise covariance for Planck low-resolution data analysis

29 páginas, 16+6 figuras, 4 tablas.-- et al.[Aims]: We develop and validate tools for estimating residual noise covariance in Planck frequency maps, we also quantify signal error effects and compare different techniques to produce low-resolution maps. [Methods]: We derived analytical estimates of covariance of the residual noise contained in low-resolution maps produced using a number of mapmaking approaches. We tested these analytical predictions using both Monte Carlo simulations and by applying them to angular power spectrum estimation. We used simulations to quantify the level of signal errors incurred in the different resolution downgrading schemes considered in this work. [Results]: We find excellent agreement between the optimal residual noise covariance matrices and Monte Carlo noise maps. For destriping mapmakers, the extent of agreement is dictated by the knee frequency of the correlated noise component and the chosen baseline offset length. Signal striping is shown to be insignificant when properly dealt with. In map resolution downgrading, we find that a carefully selected window function is required to reduce aliasing to the subpercent level at multipoles, ℓ > 2Nside, where Nside is the HEALPix resolution parameter. We show that, for a polarization measurement, reliable characterization of the residual noise is required to draw reliable constraints on large-scale anisotropy. [Conclusions]: Methods presented and tested in this paper allow for production of low-resolution maps with both controlled sky signal error level and a reliable estimate of covariance of the residual noise. We have also presented a method for smoothing the residual noise covariance matrices to describe the noise correlations in smoothed, bandwidth-limited maps.Peer reviewe

New constraints on parity symmetry from a re-analysis of the WMAP-7 low-resolution power spectra

8 páginas, 6 figuras, 3 tablas.-- El Pdf del archivo es la versión pre-print: arXiv:1006.1979v2 .-- et al.The parity symmetry of the cosmic microwave background (CMB) pattern as seen by Wilkinson Microwave Anisotropy Probe 7 yr (WMAP 7 yr) is tested jointly in temperature and polarization at large angular scale. A quadratic maximum likelihood (QML) estimator is applied to the WMAP 7-yr low-resolution maps to compute all polarized CMB angular power spectra. The analysis is supported by 10 000 realistic Monte Carlo realizations. We confirm the previously reported parity anomaly for TT in the range δℓ=[2, 22] at >99.5 per cent C.L. No anomalies have been detected in TT for a wider ℓ range (up to ℓmax= 40). No violations have been found for EE, TE and BB which we test here for the first time. The cross-spectra TB and EB are found to be consistent with zero. We also forecast Planck capabilities in probing parity violations on low-resolution maps.Support for LAMBDA is provided by the NASA Office of Space Science. This work was supported by ASI through ASI/INAF Agreement I/072/09/0 for the Planck LFI Activity of Phase E2.Peer reviewe

Assessment of ab initio models of protein complexes by molecular dynamics.

Determining how proteins interact to form stable complexes is of crucial importance, for example in the development of novel therapeutics. Computational methods to determine the thermodynamically stable conformation of complexes from the structure of the binding partners, such as RosettaDock, might potentially emerge to become a promising alternative to traditional structure determination methods. However, while models virtually identical to the correct experimental structure can in some cases be generated, the main difficulty remains to discriminate correct or approximately correct models from decoys. This is due to the ruggedness of the free-energy landscape, the approximations intrinsic in the scoring functions, and the intrinsic flexibility of proteins. Here we show that molecular dynamics simulations performed starting from a number top-scoring models can not only discriminate decoys and identify the correct structure, but may also provide information on an initial map of the free energy landscape that elucidates the binding mechanism

Computational Modeling of Designed Ankyrin Repeat Protein Complexes with their Targets

Recombinant therapeutic proteins are playing an ever-increasing role in the clinic. High-affinity binding candidates can be produced in a high-throughput manner through the process of selection and evolution from large libraries, but the structures of the complexes with target protein can only be determined for a small number of them in a costly, low-throughput manner, typically by x-ray crystallography. Reliable modeling of complexes would greatly help to understand their mode of action and improve them by further engineering, for example, by designing bi-paratopic binders. Designed ankyrin repeat proteins (DARPins) are one such class of antibody mimetics that have proven useful in the clinic, in diagnostics and research. Here we have developed a standardized procedure to model DARPin–target complexes that can be used to predict the structures of unknown complexes. It requires only the sequence of a DARPin and a structure of the unbound target. The procedure includes homology modeling of the DARPin, modeling of the flexible parts of a target, rigid body docking to ensembles of the target and docking with a partially flexible backbone. For a set of diverse DARPin–target complexes tested it generated a single model of the complex that well approximates the native state of the complex. We provide a protocol that can be used in a semi-automated way and with tools that are freely available. The presented concepts should help to accelerate the development of novel bio-therapeutics for scaffolds with similar properties

Evaluation of some habitat improvement actions in a Mediterranean area through observation of reared pheasant and red-legged partridge land uses

Red-legged partridge (Alectoris rufa) and pheasant (Phasianus colchicus) have suffered population decline in the last decades. Research suggested that decline is mainly related to the intensification of agricultural techniques and land abandonment. We evaluated habitat use and distribution of reared red-legged partridge pairs and cock pheasants in an estate representative of most of the agricultural Mediterranean areas from 2007 to 2012. Particular attention has been addressed to the effect of artificial habitat improvement actions (HIAs) and other management options such as supplemental feeding and hedgerows maintenance. We compared habitat use with its availability and analyzed spatial distribution by comparing points with pheasant cocks and partridge pairs with random ones. HIAs were used more than their availability by both species and resulted to have an important role in their distribution like hedgerows. Feeders resulted to have a strong effect on pheasant distribution, but not on pairs of red-legged partridges. Our results show that habitat management could be a fundamental tool for game-bird conservation, though the effects of feeders on red-legged partridge distribution need to be further investigated

Cosmological birefringence constraints from CMB and astrophysical polarization data

Cosmological birefringence is a rotation of the polarization plane of photons coming from sources of astrophysical and cosmological origin. The rotation can also depend on the energy of the photons and not only on the distance of the source and on the cosmological evolution of the underlying theoretical model. In this work, we constrain few selected models for cosmological birefringence, combining CMB and astrophysical data at radio, optical, X and gamma wavelengths, taking into account the specific energy and distance dependences.Comment: 12 pages, 2 figure

Survey on HIV risk perception and sexual behaviours among seafarers

Because the nature of their work seafarers spend long periods of time away from their families and therefore represent a group at risk for sexually transmitted diseases, including HIV infection. This paper reports the results of a survey to evaluate awareness and knowledge of the risk of HIV infection among seafarers. Risky behaviours for HIV transmission were also assessed. The survey was conducted using anonymous questionnaires on 197 workers of 9 vessels and 26 office employees of an Italian shipping company (FINAVAL S.p.A., Rome). The respondents considered HIV/AIDS as one of the diseases with a high risk of transmission. Most respondents had a good general knowledge of HIV/AIDS and on the ways of its transmission. However, there is still lack of knowledge on the basics of this disease. On the other hand, in spite of knowledge and awareness about the risks of the disease, only 56.35% of the interviewed crewmembers used protection in sexual intercourse with occasional partners. Compared to data available in literature, the percentage of self-protecting people is increasing, but the number of seafarers exposing themselves to risky behaviours is still high. As expected, condoms are used with regular partners with lower frequency compared to occasional intercourse. The results of this survey indicate that adequate prevention campaigns and major attention paid to seafarers health is useful for stimulating responsible conduct for the prevention of infectious diseases, including HIV infection. Nevertheless, it is still necessary to increase information about the risk of sexually transmitted diseases and how to reduce it. (Int Marit Health 2011; 62, 2: 131–137

A new, evidence-based, theory for knowledge reuse in security risk analysis

Security risk analysis (SRA) is a key activity in software engineering but requires heavy manual effort. Community knowledge in the form of security patterns or security catalogs can be used to support the identification of threats and security controls. However, no evidence-based theory exists about the effectiveness of security catalogs when used for security risk analysis. We adopt a grounded theory approach to propose a conceptual, revised and refined theory of SRA knowledge reuse. The theory refinement is backed by evidence gathered from conducting interviews with experts (20) and controlled experiments with both experts (15) and novice analysts (18). We conclude the paper by providing insights into the use of catalogs and managerial implications