University of Siena

About: University of Siena is a education organization based out in Siena, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 12179 authors who have published 33334 publications receiving 1008287 citations. The organization is also known as: Università degli studi di Siena & Universita degli studi di Siena.

The 2017 EULAR standardised procedures for ultrasound imaging in rheumatology

Abstract: Background In 2001, the European League Against Rheumatism developed and disseminated the first guidelines for musculoskeletal (MS) ultrasound (US) in rheumatology. Fifteen years later, the dramatic expansion of new data on MSUS in the literature coupled with technological developments in US imaging has necessitated an update of these guidelines. Objectives To update the existing MSUS guidelines in rheumatology as well as to extend their scope to other anatomic structures relevant for rheumatology. Methods The project consisted of the following steps: (1) a systematic literature review of MSUS evaluable structures; (2) a Delphi survey among rheumatologist and radiologist experts in MSUS to select MS and non-MS anatomic structures evaluable by US that are relevant to rheumatology, to select abnormalities evaluable by US and to prioritise these pathologies for rheumatology and (3) a nominal group technique to achieve consensus on the US scanning procedures and to produce an electronic illustrated manual (ie, App of these procedures). Results Structures from nine MS and non-MS areas (ie, shoulder, elbow, wrist and hand, hip, knee, ankle and foot, peripheral nerves, salivary glands and vessels) were selected for MSUS in rheumatic and musculoskeletal diseases (RMD) and their detailed scanning procedures (ie, patient position, probe placement, scanning method and bony/other landmarks) were used to produce the App. In addition, US evaluable abnormalities present in RMD for each anatomic structure and their relevance for rheumatology were agreed on by the MSUS experts. Conclusions This task force has produced a consensus-based comprehensive and practical framework on standardised procedures for MSUS imaging in rheumatology.

Eurozone sovereign contagion: Evidence from the CDS market (2005–2010)

Abstract: This paper analyses the dynamics of the credit default swap (CDS) market of PIIGS, France, Germany and the UK for the period of 2005–2010. The study is performed on the basis of the Datastream and DTCC data on CDS spreads and the BIS data on cross-border exposures. The analysis of the data shows that sovereign risk mainly concentrates in the EU countries. The EWMA correlation analysis and the Granger-causality test demonstrate that there was contagion effect since correlations and cross-county interdependencies increased already after August 2007. Furthermore, the IRF analysis shows that among PIIGS the CDS markets of Spain and Ireland have the biggest impact on the European CDS market, whereas the CDS market of the UK does not cause a big distress in the Eurozone. The adjusted correlation analysis confirms that Greece and other PIIGS (even Spain and Italy) have lower capacity to trigger contagion than core EU countries. Besides, Portugal is the most vulnerable country in the sample, whereas the UK is the most immune to shocks.

Prevalent vertebral deformity predicts incident hip though not distal forearm fracture: results from the European Prospective Osteoporosis Study.

Abstract: The presence of a vertebral deformity increases the risk of subsequent spinal deformities. The aim of this analysis was to determine whether the presence of vertebral deformity predicts incident hip and other limb fractures. Six thousand three hundred and forty-four men and 6788 women aged 50 years and over were recruited from population registers in 31 European centers and followed prospectively for a median of 3 years. All subjects had radiographs performed at baseline and the presence of vertebral deformity was assessed using established morphometric methods. Incident limb fractures which occurred during the follow- up period were ascertained by annual postal questionnaire and confirmed by radiographs, review of medical records and personal interview. During a total of 40348 person-years of follow-up, 138 men and 391 women sustained a limb fracture. Amongst the women, after adjustment for age, prevalent vertebral deformity was a strong predictor of incident hip fracture, (rate ratio (RR) = 4.5; 95% CI 2.1-9.4) and a weak predictor of 'other' limb fractures (RR = 1.6; 95% CI 1.1-2.4), though not distal forearm fracture (RR = 1.0; 95% CI 0.6-1.6). The predictive risk increased with increasing number of prevalent deformities, particularly for subsequent hip fracture: for two or more deformities, RR = 7.2 (95% CI 3.0-17.3). Amongst men, vertebral deformity was not associated with an increased risk of incident limb fracture though there was a nonsignificant trend toward an increased risk of hip fracture with increasing number of deformities. In summary, prevalent radiographic vertebral deformities in women are a strong predictor of hip fracture, and to a lesser extent humerus and 'other' limb fractures; however, they do not predict distal forearm fractures.

A Standard Siren Measurement of the Hubble Constant from GW170817 without the Electromagnetic Counterpart

Abstract: We perform a statistical standard siren analysis of GW170817. Our analysis does not utilize knowledge of NGC 4993 as the unique host galaxy of the optical counterpart to GW170817. Instead, we consider each galaxy within the GW170817 localization region as a potential host; combining the redshifts from all of the galaxies with the distance estimate from GW170817 provides an estimate of the Hubble constant, H 0. Considering all galaxies brighter than $0.626{L}_{B}^{\star }$ as equally likely to host a binary neutron star merger, we find ${H}_{0}={77}_{-18}^{+37}$ km s−1 Mpc−1 (maximum a posteriori and 68.3% highest density posterior interval; assuming a flat H 0 prior in the range $\left[10,220\right]$ km s−1 Mpc−1). We explore the dependence of our results on the thresholds by which galaxies are included in our sample, and we show that weighting the host galaxies by stellar mass or star formation rate provides entirely consistent results with potentially tighter constraints. By applying the method to simulated gravitational-wave events and a realistic galaxy catalog we show that, because of the small localization volume, this statistical standard siren analysis of GW170817 provides an unusually informative (top 10%) constraint. Under optimistic assumptions for galaxy completeness and redshift uncertainty, we find that dark binary neutron star measurements of H 0 will converge as $40 \% /\sqrt{(N)}$, where N is the number of sources. While these statistical estimates are inferior to the value from the counterpart standard siren measurement utilizing NGC 4993 as the unique host, ${H}_{0}={76}_{-13}^{+19}$ km s−1 Mpc−1 (determined from the same publicly available data), our analysis is a proof-of-principle demonstration of the statistical approach first proposed by Bernard Schutz over 30 yr ago.

Pollen Germination and Pollen Tube Growth

Abstract: Pollen, the male gametophyte of higher plants, is a biological system playing a central role in sexual plant reproduction (Cresti et al., 1992). The understanding of the mechanisms controlling the various aspects of pollen tube development has a direct relevance to biotechnological applications since it represents a starting point to modify crop production and it enhances the knowledge on molecular and cellular events controlling the tip growth mechanism. When pollen arrives on the surface of a compatible stigma it undergoes a complex series of regulated cytoplasmic rearrangements leading to the emergence of a cylindrical structure known as pollen tube, with the main purpose to carry and deliver sperm cells to the embryo sac for the double fertilization. In vivo, pollen tubes grow through the transmitting tissue in the style and, since they never penetrate stigmatic cells, the mechanisms involving cell-cell recognition and signalling must exist to guide pollen tubes to the ovary. For this purpose, specific molecules of the transmitting tissue acting as adhesive substrate, attractants and stimulators of pollen tube elongation (Lord and Sanders, 1992) have been identified and characterized in several angiosperms but pollen tube targets of these external stimuli and the nature of these interactions have not been fully understood at the molecular level (Frankling-Tong, 1999).