Estimating hyperparameters and instrument parameters in regularized inversion. Illustration for SPIRE/Herschel map making

We describe regularized methods for image reconstruction and focus on the question of hyperparameter and instrument parameter estimation, i.e. unsupervised and myopic problems. We developed a Bayesian framework that is based on the \post density for all unknown quantities, given the observations. This density is explored by a Markov Chain Monte-Carlo sampling technique based on a Gibbs loop and including a Metropolis-Hastings step. The numerical evaluation relies on the SPIRE instrument of the Herschel observatory. Using simulated and real observations, we show that the hyperparameters and instrument parameters are correctly estimated, which opens up many perspectives for imaging in astrophysics

Hormonal signals involved in the regulation of cambial activity, xylogenesis and vessel patterning in trees

The radial growth of plant stem is based on the development of cribro-vascular cambium tissues. It affects the transport efficiency of water, mineral nutrients and photoassimilates and, ultimately, also plant height. The rate of cambial cell divisions for the assembly of new xylem and phloem tissue primordia and the rate of differentiation of the primordia into mature tissues determine the amount of biomass produced and, in the case of woody species, the wood quality. These complex physiological processes proceed at a rate which depends on several factors, acting at various levels: growth regulators, resource availability and environmental factors. Several hormonal signals and, more recently, further regulatory molecules, have been shown to be involved in the induction and maintenance of cambium and the formation of secondary vascular tissues. The control of xylem cell patterning is of particular interest, because it determines the diameter of xylem vessels, which is central to the efficiency of water and nutrient transport from roots to leaves through the stem and may strongly influence the growth in height of the tree. Increasing scientific evidence have proved the role of other hormones in cambial cell activities and the study of the hormonal signals and their crosstalking in cambial cells may foster our understanding of the dynamics of xylogenesis and of the mechanism of vessel size control along the stem. In this article, the role of the hormonal signals involved in the control of cambium and xylem development in trees and their crosstalking are reviewed

Determining the optimal piecewise constant approximation for the nonhomogeneous Poisson process rate of Emergency Department patient arrivals

Modeling the arrival process to an Emergency Department (ED) is the first step of all studies dealing with the patient flow within the ED. Many of them focus on the increasing phenomenon of ED overcrowding, which is afflicting hospitals all over the world. Since Discrete Event Simulation models are often adopted to assess solutions for reducing the impact of this problem, proper nonstationary processes are taken into account to reproduce time–dependent arrivals. Accordingly, an accurate estimation of the unknown arrival rate is required to guarantee the reliability of results. In this work, an integer nonlinear black–box optimization problem is solved to determine the best piecewise constant approximation of the time-varying arrival rate function, by finding the optimal partition of the 24 h into a suitable number of not equally spaced intervals. The black-box constraints of the optimization problem make the feasible solutions satisfy proper statistical hypotheses; these ensure the validity of the nonhomogeneous Poisson assumption about the arrival process, commonly adopted in the literature, and prevent mixing overdispersed data for model estimation. The cost function of the optimization problem includes a fit error term for the solution accuracy and a penalty term to select an adequate degree of regularity of the optimal solution. To show the effectiveness of this methodology, real data from one of the largest Italian hospital EDs are used

Super-resolution in map-making based on a physical instrument model and regularized inversion. Application to SPIRE/Herschel

We investigate super-resolution methods for image reconstruction from data provided by a family of scanning instruments like the Herschel observatory. To do this, we constructed a model of the instrument that faithfully reflects the physical reality, accurately taking the acquisition process into account to explain the data in a reliable manner. The inversion, ie the image reconstruction process, is based on a linear approach resulting from a quadratic regularized criterion and numerical optimization tools. The application concerns the reconstruction of maps for the SPIRE instrument of the Herschel observatory. The numerical evaluation uses simulated and real data to compare the standard tool (coaddition) and the proposed method. The inversion approach is capable to restore spatial frequencies over a bandwidth four times that possible with coaddition and thus to correctly show details invisible on standard maps. The approach is also applied to real data with significant improvement in spatial resolution.Comment: Astronomy & Astrophysic

Potential impact of a nonavalent HPV vaccine on HPV related low-and high-grade cervical intraepithelial lesions: A referral hospital-based study in Sicily

While bivalent and quadrivalent HPV vaccines have been used for about 10 years, a nonavalent vaccine against HPV types 6/11/16/18/31/33/45/52 and 58 has been recently approved by FDA and EMA and is now commercially available. The objective of our study was to evaluate the potential impact of the nonavalent vaccine on HPV infection and related low- and high-grade squamous intraepithelial lesions (LSIL, HSIL), compared to the impact of the quadrivalent vaccine, in a female population living in Sicily (Italy). Low estimates of HPV vaccine impact were calculated as prevalence of HPV 6/11/16/18/31/33/45/52 and 58 genotypes, alone or in association, but excluding presence of other HPV types; high estimates were calculated as prevalence of HPV 6/11/16/18/31/33/45/52 and 58 genotypes alone or in association, in the presence of other HPV types. The nonavalent HPV vaccine showed increased impact, compared to the quadrivalent vaccine. Estimates of potential impact varied from 30.9% (low estimate) to 53.3% (high estimate) for LSIL, and from 56.9% to 81,0% for HSIL. The proportion of additional cases potentially prevented by the nonavalent vaccine was 14.4%\u201323.8% for LSIL, and 19.0%\u201332.8% for HSIL. The benefit of the nonavalent vaccine compared to the quadrivalent vaccine was more than 80% for both low and high impact estimates for LSIL and more than 50% for both low and high impact estimates for HSIL. The present study confirms that the switch from a first generation HPV vaccines to a nonavalent vaccine would increase the prevention of cervical HSIL in up to 90% of cases

DATA INVERSION FOR HYPERSPECTRAL OBJECTS IN ASTRONOMY

ABSTRACT We present an original method for reconstruction of hyperspectral objects (two spatial and one spectral dimensions) from data provided by the infrared slit spectrograph on board the Spitzer Space Telescope. The originality of the work lies in the fact that both measurement model and inversion method are tackled in continuous (spatial and spectral) variables. The method is built in a deterministic regularization framework and enable to achieve both deconvolution and over-resolution. Results show that the method is able to evidence spatial structures not detectable by means of conventional methods. The spatial resolution is shown to be improved by a factor 1.5. We discuss our data processing approach for the new generation of infrared to millimeter space observatories launched in 2009 (Herschel and Planck)

The broad-band X-ray spectrum of RE 0751+14 (PQ Gem)

RE 0751+14 is a member of the class of Soft Intermediate Polars. Unlike classical Intermediate Polars, they are characterized by the presence of a soft component in their X-ray spectra, in addition to the hard component typical of these systems. The broad-band coverage of the Narrow-Field instruments on board BeppoSAX is ideal for the study of such objects. Here we report the preliminary results of the analysis of a BeppoSAX pointing to RE 0751+14. Both components are clearly detected, and their temperature determined (~50 eV and ~40 keV), enabling the possibility of studying them simultaneously

Introduction: Deep carbon cycle through five reactions

What are the key reactions driving the global carbon cycle in Earth, the only known habitable planet in the Solar System? And how do chemical reactions govern the transformation and movement of carbon? The special collection “Earth in Five Reactions: A Deep Carbon Perspective” features review articles synthesizing knowledge and findings on the role of carbon-related reactions in Earth's dynamics and evolution. These integrative studies identify gaps in our current understanding and establish new frontiers to motivate and guide future research in deep carbon science. The collection also includes original experimental and theoretical investigations of carbon-bearing phases and the impact of chemical and polymorphic reactions on Earth's deep carbon cycle

Sunscreens Cause Coral Bleaching by Promoting Viral Infections

Background: Coral bleaching (i.e., the release of coral symbiotic zooxanthellae) has negative impacts on biodiversity and functioning of reef ecosystems and their production of goods and services. This increasing world-wide phenomenon is associated with temperature anomalies, high irradiance, pollution, and bacterial diseases. Recently, it has been demonstrated that personal can products, including sunscreens, have an impact on aquatic organisms similar to that of other contaminants. Objectives: Our goal was to evaluate the potential impact of sunscreen ingredients on hard corals and their symbiotic algae. Methods: In situ and laboratory experiments were conducted in several tropical regions (the Atlantic, Indian, and Pacific Oceans, and the Red Sea) by supplementing coral branches with aliquots of sunscreens and common ultraviolet filters contained in sunscreen formula. Zooxanthellae were checked for viral infection by epifluorescence and transmission electron microscopy analyses. Results: Sunscreens cause the rapid and complete bleaching of hard corals, even at extremely low concentrations. The effect of sunscreens is due to organic ultraviolet filters, which are able to induce the lyric viral cycle in symbiotic zooxanthellae with latent infections. Conclusions: We conclude that sunscreens, by promoting viral infection, potentially play an important role in coral bleaching in areas prone to high levels of recreational use by humans