Design and Field Measurements of a Linear Accelerator Endowed with Single Feed with Movable Short Coupler

Field asymmetries in the rf coupler of accelerating structures degrade the projected beam transverse emittance, especially at low energy. This paper presents an alternative single feed coupler design that reduces the dipolar and the quadrupolar field components by exploiting a movable short circuit placed on the opposite waveguide. The structure has been simulated and optimized with the Ansys HFSS simulation code. RF measurements on an aluminum prototype machined in the "Elettra - Sincrotrone Trieste S.C.p.A.", are here presented. Such results are in good agreement with the simulations

Static response and Love numbers of Schwarzschild black holes

We derive the quadratic action for the physical degrees of freedom of massless spin-0, spin-1, and spin-2 perturbations on a Schwarzschild-(A)dS background in arbitrary dimensions. We then use these results to compute the static response of asymptotically flat Schwarzschild black holes to external fields. Our analysis reproduces known facts about black hole Love numbers-in particular that they vanish for all types of perturbation in four spacetime dimensions-but also leads to new results. For instance, we find that neutral Schwarzschild black holes polarize in the presence of an electromagnetic background in any number of spacetime dimensions except four. Moreover, we calculate for the first time black hole Love numbers for vector-type gravitational perturbations in higher dimensions and find that they generically do not vanish. Along the way, we shed some light on an apparent discrepancy between previous results in the literature, and clarify some aspects of the matching between perturbative calculations of static response on a Schwarzschild background and the point-particle effective theory.</p

Near-Zone Symmetries of Kerr Black Holes

We study the near-zone symmetries of a massless scalar field on four-dimensional black hole backgrounds. We provide a geometric understanding that unifies various recently discovered symmetries as part of an SO(4,2) group. Of these, a subset are exact symmetries of the static sector and give rise to the ladder symmetries responsible for the vanishing of Love numbers. In the Kerr case, we compare different near-zone approximations in the literature, and focus on the implementation that retains the symmetries of the static limit. We also describe the relation to spin-1 and 2 perturbations.Comment: 4+3 pages, 1 figur

Giving meaning to alternative methods to animal testing

The 3 rd edition of the advanced theoretical-training course \u201c Giving meaning to alternative methods to animal testing \u201d was held in Genoa on July 6-7, 2017. The theoretical modules included talks by specialists from companies engaged in the field of advanced in vitro technologies, who offered participants the possibility to try out their technologies in the training modules

Partnering with Parteras: Multi-Collaborator International Service-Learning Project Impacts on Traditional Birth Attendants in Mexico

Medical students are increasingly seeking global health service-learning opportunities; however, the impact of these interventions is often not assessed. In this article, the authors describe a model for global health service-learning programs as well as a pilot tool for assessing program impacts on populations traditionally difficult to evaluate.  Specifically, a group of medical students from the United States, in collaboration with local health officials and a global NGO, successfully implemented a training program for parteras, or traditional birth attendants, in Mexico. The training included educational objectives from the Ministry of Health.  A pilot assessment tool was developed which included oral pretest and posttest self-reported knowledge and task-specific ability in 12 program-specific categories. The assessment was administered in an effort to determine educational impact: parteras, who were receptive to students as teachers, reported increased knowledge and skill in all topics except nutrition and postpartum care. The results of the assessment suggest that undergraduate medical students, when collaborating with a facilitating organization, community-based healthcare workers, and local ministries of health, can improve lay birth attendants’ confidence in basic obstetric knowledge and skills through global service-learning. Moreover, creative assessments are required to understand impacts on difficult to access populations.

Different gene expression modulation is the major effect fue to shear stress and stent application in huvecs model: preliminary results

Although it is known that disturbed shear stress may cause endothelial damage, the mechanism by which a stent procedure may affect the endothelium is not yet fully clarify. We present the preliminary data on gene expression analysis of human endothelial cells in a laminar flow bioreactor (LFB) system submitted to different physical (flow changes) and/or mechanical (stent application) stimuli. Our preliminary results show that low shear stress together with stent procedure are the experimental conditions that mainly modulate the highest number of genes in human endothelial model. Those genes belong to pathways specifically involved in the endothelial dysfunctio

Influence of residual perfusion within the infarct zone on the natural history of left ventricular dysfunction after acute myocardial infarction.

This study used myocardial contrast echocardiography to investigate the extent of residual perfusion within the infarct zone in a select group of patients with recently reperfused myocardial infarction and evaluated its influence on the ultimate infarct size. BACKGROUND: Limited information is available on the status of myocardial perfusion within postischemic dysfunctional segments at predischarge and on its influence on late regional and global functional recovery. METHODS: Twenty patients with acute myocardial infarction were selected for the study. Patients met the following inclusion criteria: 1) single-vessel coronary artery disease; 2) patency of infarct-related artery with persistent postischemic dysfunctional segments at predischarge; 3) stable clinical condition up to 6 months after hospital discharge. All selected patients underwent coronary angiography and myocardial contrast echocardiography before hospital discharge and repeated the echocardiographic examination 6 months later. Patients were grouped according to the pattern of contrast enhancement in predischarge dysfunctional segments. RESULTS: In nine patients (group I), the length of segments showing abnormal contraction coincided with that of the contrast defect segments. In the remaining 11 patients (group II), postischemic dysfunctional segments were partly or completely reperfused. There was no difference between the two groups in asynergic segment length at predischarge (7.3 +/- 2.5 vs. 7.2 +/- 4.3 cm, p = NS). At follow-up study, asynergic segment length was significantly reduced in group II patients, whereas no changes were observed in group I patients (from 7.2 +/- 4.3 to 4.7 +/- 3.7 cm, p < 0.005; and from 7.3 +/- 2.5 to 7.5 +/- 2.9 cm, p = NS, respectively). CONCLUSIONS: Among patients with a predischarge patent infarct-related artery, further improvement in regional and global function may be expected during follow-up when residual perfusion in the infarct zone is present