Planck pre-launch status: High Frequency Instrument polarization calibration

The High Frequency Instrument of Planck will map the entire sky in the millimeter and sub-millimeter domain from 100 to 857 GHz with unprecedented sensitivity to polarization (ΔP/T_(cmb) ~ 4 × 10^(-6) for P either Q or U and T_(cmb) ≃ 2.7 K) at 100, 143, 217 and 353 GHz. It will lead to major improvements in our understanding of the cosmic microwave background anisotropies and polarized foreground signals. Planck will make high resolution measurements of the E-mode spectrum (up to l ~ 1500) and will also play a prominent role in the search for the faint imprint of primordial gravitational waves on the CMB polarization. This paper addresses the effects of calibration of both temperature (gain) and polarization (polarization efficiency and detector orientation) on polarization measurements. The specific requirements on the polarization parameters of the instrument are set and we report on their pre-flight measurement on HFI bolometers. We present a semi-analytical method that exactly accounts for the scanning strategy of the instrument as well as the combination of different detectors. We use this method to propagate errors through to the CMB angular power spectra in the particular case of Planck-HFI, and to derive constraints on polarization parameters. We show that in order to limit the systematic error to 10% of the cosmic variance of the E-mode power spectrum, uncertainties in gain, polarization efficiency and detector orientation must be below 0.15%, 0.3% and 1° respectively. Pre-launch ground measurements reported in this paper already fulfill these requirements

Follow-up question handling in the IMIX and Ritel systems: A comparative study

One of the basic topics of question answering (QA) dialogue systems is how follow-up questions should be interpreted by a QA system. In this paper, we shall discuss our experience with the IMIX and Ritel systems, for both of which a follow-up question handling scheme has been developed, and corpora have been collected. These two systems are each other's opposites in many respects: IMIX is multimodal, non-factoid, black-box QA, while Ritel is speech, factoid, keyword-based QA. Nevertheless, we will show that they are quite comparable, and that it is fruitful to examine the similarities and differences. We shall look at how the systems are composed, and how real, non-expert, users interact with the systems. We shall also provide comparisons with systems from the literature where possible, and indicate where open issues lie and in what areas existing systems may be improved. We conclude that most systems have a common architecture with a set of common subtasks, in particular detecting follow-up questions and finding referents for them. We characterise these tasks using the typical techniques used for performing them, and data from our corpora. We also identify a special type of follow-up question, the discourse question, which is asked when the user is trying to understand an answer, and propose some basic methods for handling it

Cell-type-specific resolution epigenetics without the need for cell sorting or single-cell biology.

High costs and technical limitations of cell sorting and single-cell techniques currently restrict the collection of large-scale, cell-type-specific DNA methylation data. This, in turn, impedes our ability to tackle key biological questions that pertain to variation within a population, such as identification of disease-associated genes at a cell-type-specific resolution. Here, we show mathematically and empirically that cell-type-specific methylation levels of an individual can be learned from its tissue-level bulk data, conceptually emulating the case where the individual has been profiled with a single-cell resolution and then signals were aggregated in each cell population separately. Provided with this unprecedented way to perform powerful large-scale epigenetic studies with cell-type-specific resolution, we revisit previous studies with tissue-level bulk methylation and reveal novel associations with leukocyte composition in blood and with rheumatoid arthritis. For the latter, we further show consistency with validation data collected from sorted leukocyte sub-types

On certain modules of covariants in exterior algebras

We study the structure of the space of covariants $B:=\left(\bigwedge (\mathfrak g/\mathfrak k)^*\otimes \mathfrak g\right)^{\mathfrak k},$ for a certain class of infinitesimal symmetric spaces $(\mathfrak g,\mathfrak k)$ such that the space of invariants $A:=\left(\bigwedge (\mathfrak g/\mathfrak k)^*\right)^{\mathfrak k}$ is an exterior algebra $\wedge (x_1,...,x_r),$ with $r=rk(\mathfrak g)-rk(\mathfrak k)$. We prove that they are free modules over the subalgebra $A_{r-1}=\wedge (x_1,...,x_{r-1})$ of rank $4r$. In addition we will give an explicit basis of $B$. As particular cases we will recover same classical results. In fact we will describe the structure of $\left(\bigwedge (M_n^{\pm})^*\otimes M_n\right)^G$, the space of the $G-$equivariant matrix valued alternating multilinear maps on the space of (skew-symmetric or symmetric with respect to a specific involution) matrices, where $G$ is the symplectic group or the odd orthogonal group. Furthermore we prove new polynomial trace identities.Comment: Title changed. Results have been generalised to other infinitesimal symmetric space

Total knee arthroplasty in valgus knee

SummaryTotal knee arthroplasty (TKA) in valgus knee has the reputation of being more difficult than in well aligned or varus knee, and there is no management consensus. Results on a continuous series of 100 TKAs on valgus knee were compared to the literature data, to define surgical strategy adapted to the various types of valgus knee

Numerical size estimates of inclusions in Kirchhoff-Love elastic plates

The size estimates approach for Kirchhoff--Love elastic plates allows to determine upper and lower bounds of the area of an unknown elastic inclusion by measuring the work developed by applying a couple field on the boundary of the plate. Although the analytical process by which such bounds are determined is of constructive type, it leads to rather pessimistic evaluations. In this paper we show by numerical simulations how to obtain such bounds for practical applications of the method. The computations are developed for a square plate under various boundary loads and for inclusions of different position, shape and stiffness. The sensitivity of the results with respect to the relevant parameters is also analyzed

Paleogeographic Interpretation of a Peat Layer at Torson di Sotto (Lagoon of Venice, Italy)

Ein 3,3 m langer Kern aus dem zentralen Bereich der Lagune von Venedig enthielt eine Torflage zwischen 1,3 und 2,0 m unter dem mittleren Meeresspiegel. Pollenanalysen zeigen ein Vorherrschen von Quercus und Alnus und eine transgressive Phase an: der untere Teil des Torfes (nach 14C-Daten 1730±80 v.h.) ist in einem Süßwasser-Environment gebildet worden, der obere Teil (nach 14C-Daten 1140 + 80 v.h.) in einem brackischen. Foraminiferenanalysen zeigen an, daß der Transgression eine Regression vorangegangen ist. Die gesamte Abfolge enthält von unten nach oben (Abb. 3): (1) ein oligohalines bis mesohalines Environment (von —3,3 bis —2,5 m) mit sehr zahlreichen Foraminiferen; (2) ein Süßwasser-Environment (von —2,5 bis —2,0 m); (3) die 0,7 m mächtige Torflage, die fortschreitend brackisch wird; (4) ein mesohalines Environment (oberhalb —1,3 m).Korrelationen mit benachbarten Lokalitäten (Abb. 1) weisen darauf hin, daß vergleichbare Erscheinungen zu gleicher Zeit im Zentralteil der Lagune, aber nicht in ihrem Nordteil, aufgetreten sind. Diese Regressions-Transgressions-Abfolge wird auf eine Periode erhöhter Niederschläge um das Ende der Römerzeit zurückgeführt, die zur Überflutung und zu einer Verlagerung des Laufes zahlreicher Flüsse geführt hat; dabei ist das ökologische Gleichgewicht dieses Marschengebietes zeitweilig verändert worden. Im Verlauf der vergangenen 100 Jahre hat sich die Transgression beschleunigt, überwiegend infolge anthropogener Eingriffe. Die „Barene" werden jetzt erodiert und verschwinden rasch (Abb. 2). Sie werden durch weite Meerwasserbecken eingenommen.researc

Gas fields and large shallow seismogenic reverse faults are anticorrelated

We investigated the spatial relationships among 18 known seismogenic faults and 1651 wells drilled for gas exploitation in the main hydrocarbon province of northern-central Italy, a unique dataset worldwide. We adopted a GIS approach and a robust statistical technique, and found a significant anticorrelation between the location of productive wells and of the considered seismogenic faults, which are often overlain or encircled by unproductive wells. Our observations suggest that (a) earthquake ruptures encompassing much of the upper crust may cause gas to be lost to the atmosphere over geological time, and that (b) reservoirs underlain by smaller or aseismic faults are more likely to be intact. These findings, which are of inherently global relevance, have crucial implications for future hydrocarbon exploitation, for assessing the seismic-aseismic behaviour of large reverse faults, and for the public acceptance of underground energy and CO2 storage facilities-a pillar of future low carbon energy systems-in tectonically active areas